Bacteriophage Ecology Group Reference Abstracts (1998)
	Dedicated to the ecology and evolutionary biology of the parasites of unicellular organisms (UOPs)
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© Phage et al.	last updated on Wednesday, December 26, 2001

1. Horizontal Gene Transfer. Anonymous (1998). Chapman & Hall, New York.[TOP OF PAGE]

2. A phage DNA injection-blocking type resistance mechanism encoded by chromosomal DNA in Lactococcus lactis subsp. lactis PLM-18. ??? (1998). Milchwissenschaft 53:619-622. Lactococcus lactis subsp. lactis strain PLM-18 has a phage resistance activity against variant f la2 which resulted in phage DNA injection-blocking. After adsorption of variant f la2 to PLM-18 and its plasmid free derivative MA-12 cells with the same adsorption rate (98.4%), phage DNA was detected in neither PLM-18 nor MA-12 cells while detecting variant f la2 DNA in sensitive host LLA-111 after 5 min. following phage adsorption. However, electrotransformation of phage DNA into resistant hosts, PLM-18 and MA-12, resulted in release of phage progeny on the contrary of conventional infection assays. [TOP OF PAGE]

3. In vivo transduction with Shiga toxin 1-encoding phage. Acheson, D.W.K., Reidl, J., Zhang, X., Keusch, G.T., Mekalanos, J.J., Waldor, M.K. (1998). Infect. Immun. 66:4496-4498. [TOP OF PAGE]

4. Tailed bacteriophages: the order caudovirales. Ackermann, H.-W. (1998). Advances in Virus Research 51:135-201. Tailed bacteriophages have a common origin and constitute an order with three families, named Caudovirales. Their structured tail is unique. Tailed phages share a series of high-level taxonomic properties and show many facultative features that are unique or rare in viruses, for example, tail appendages and unusual bases. They share with other viruses, especially herpesviruses, elements of morphogenesis and life-style that are attributed to convergent evolution. Tailed phages present three types of lysogeny, exemplified by phages lambda, Mu, and P1. Lysogeny appears as a secondary property acquired by horizontal gene transfer. Amino acid sequence alignments (notably of DNA polymerases, integrases, and peptidoglycan hydrolases) indicate frequent events of horizontal gene transfer in tailed phages. Common capsid and tail proteins have not been detected. Tailed phages possibly evolved from small protein shells with a few genes sufficient for some basal level of productive infection. This early stage can no longer be traced. At one point, this precursor phage became perfected. Some of its features were perfect enough to be transmitted until today. It is tempting to list major present-day properties of tailed phages in the past tense to construct a tentative history of these viruses: 1. Tailed phages originated in the early Precambrian, long before eukaryotes and their viruses. 2. The ur-tailed phage, already a quite evolved virus, had an icosahedral head of about 60 nm in diameter and a long non-contractile tail with sixfold symmetry. The capsid contained a single molecule of dsDNA of about 50 kb, and the tail was probably provided with a fixation apparatus. Head and tail were held together by a connector. a. The particle contained no lipids, was heavier than most viruses to come, and had a high DNA content proportional to its capsid size (about 50%). b. Most of its DNA coded for structural proteins. Morphopoietic genes clustered at one end of the genome, with head genes preceding tail genes. Lytic enzymes were probably coded for. A part of the phage genome was nonessential and possibly bacterial. Were tailed phages general transductants since the beginning? 3. The virus infected its host from the outside, injecting its DNA. Replication involved transcription in several waves and formation of DNA concatemers. Novel phages were released by burst of the infected cell after lysis of host membranes by a peptidoglycan hydrolase (and a holin?). a. Capsids were assembled from a starting point, the connector, and around a scaffold. They underwent an elaborate maturation process involving protein cleavage and capsid expansion. Heads and tails were assembled separately and joined later. b. The DNA was cut to size and entered preformed capsids by a headful mechanism. 4. Subsequently, tailed phages diversified by: a. Evolving contractile or short tails and elongated heads. b. Exchanging genes or gene fragments with other phages. c. Becoming temperate by acquiring an integrase-excisionase complex, plasmid parts, or transposons. d. Acquiring DNA and RNA polymerases and other replication enzymes. e. Exchanging lysin genes with their hosts. f. Losing the ability to form concatemers as a consequence of acquiring transposons (Mu) or proteinprimed DNA polymerases (phi 29). Present-day tailed phages appear as chimeras, but their monophyletic origin is still inscribed in their morphology, genome structure, and replication strategy. It may also be evident in the three-dimensional structure of capsid and tail proteins. It is unlikely to be found in amino acid sequences because constitutive proteins must be so old that relationships were obliterated and most or all replication-, lysogeny-, and lysis-related proteins appear to have been borrowed. However, the sum of tailed phage properties and behavior is so characteristic that tailed phages cannot be confused with other viruses. [TOP OF PAGE]

5. Dissolved esterase activity as a tracer of physoplankton lysis: Evidence of high phytoplankton lysis rates in the northwestern Mediteranean. Agustí, S., Satta, M.P., Mura, M.P., Benavent, E. (1998). Limnol. Oceanogr. 43:1836-1849. Phytoplankton cell lysis is perceived to be an important loss process in the sea, although a quantification of this process has proved elusive. A recently developed method, based on the measurement of dissolved esterase activity (EA), was used to estimate the release of esterases following phytoplankton cell lysis in an effort to evaluate the importance of this process as a loss factor in the summer phytoplankton of the northwestern Mediterranean Sea. Implicit in this method was the assumption that only the lysis of phytoplankton cells caused these enzymes to be released to the medium. This assumption was tested by analyzing the presence and release of esterases by marine bacteria, heterotrophic flagellates, and heterotrophic ciliates, all isolated from the Blanes Bay (northwestern Mediterranean, Spain), and by phytoplankton grown in culture (Synechococcus elongatus, Dunaliella sp., Chlorella sp., Phaeodactyllum tricornutum, and Chaetoceros decipiens). The dissolved EA found during the growth, stationary, and decay phases of microheterotrophs (bacteria, flagellate, and ciliate) was negligible when compared to that found for phytoplanktonic cultures. Differences in cell volume explained the differences in cell EA among the organisms, but heterotrophs showed lower cell EA (10-50-fold) than phytoplanktonic cells of similar cell size. These results support the assumption that microheterotrophs do not contribute significant amounts of EA to the dissolved pear, allowing the use of the method to estimate phytoplankton lysis. Independent estimates of cell, loss in phytoplankton cultures, derived from cell cycle analysis, confirmed the estimates of cell lysis obtained from the measurement of dissolved EA.
   
   During the study conducted in the Mediterranean Sea, the water column was strongly stratified, showing a deep (40-55 m) chlorophyll a (Chl a) maximum (DCM; 1.25 +/- 0.09 mu g liter^-1) and low surface Chl a concentrations (0.09 +/- 0.008 mu g liter(-1)). Phytoplankton lysis rates ranged between 0.026 d^-1 and 1.9 d^-1, and they declined significantly with depth; the fastest rates were found in surface waters and the slowest ones at the DCM. Despite the fast gross growth rates of surface phytoplankton las calculated from phytoplankton biovolume and oxygen production), the calculated lysis rates represented a considerable proportion of gross phytoplankton growth rate (50%) at the surface, whereas they were comparatively less important at the DCM (7%). These results provide strong evidence that phytoplankton lysis can be an important loss factor in the surface waters of this stratified, oligotrophic sea. Phytoplankton lysis could provide the loss factor needed to explain the low phytoplankton biomass despite fast growth and low grazing rates in the northwestern Mediterranean surface waters. The high lysis rate of phytoplankton in surface waters represents an important path by which primary production may fuel the growth of microheterophic organisms, consistent with the high respiration rate of the surface community examined. The conclusion that phytoplankton lysis rates can occur at rates high enough to influence food web dynamics and biogeochemical cycles in the oligotrophic ocean should stimulate research on this largely neglected loss factor in phytoplankton ecology. [TOP OF PAGE]

6. Construction of multiple phage resistance in Lactococcus lactis subsp. lactis. Akcelik, M. (1998). Advances in Food Sciences 20:101-104. The conjugative 37.5 Kb plasmid encodes inhibition of phage adsorption (Ads+) in Lactococcus lactis subsp. lactis P25, transferred into L. lactis subsp. lactis MA12 carrying chromosomally encoded inhibition of phage DNA injection (f⁺) type resistance. The Lac⁺, Strr, Kmr, Phi⁺ and Ads⁺ representative transconjugant PMA3 strain demonstrated full resistance to the prolate-headed phages which were not inhibited by f⁺ mechanism in the recipient strain MA12. Plasmid p2520L was found to be completely stable in the transconjugant strain PMA3 after growing this strain in 10% RSM for 75 generations. [TOP OF PAGE]

7. Rekominatsionnoe proiskhozhdenie prirodnykh fagov-transpozonov rodstvennykh vidov gruppy B3, aktivnykh na bakteriiakh vida Pseudomonas aeruginosa [Recombinational origin of natural transposable phages of related species belonging to group B3, active in Pseudomonas aeruginosa species]. Akhverdian, V.Z., Lobanov, A.O., Khrenova, E.A., Krylov, V.N. (1998). Genetika 34:697-700. A heteroduplex analysis of four related transposable phages--B3, PM57, PM62, and Hw12--of the Pseudomonas aeruginosa B3 group was performed. Heteroduplex structures, restriction maps, and data on DNA-DNA hybridization obtained upon hybridization of phage DNA restriction fragments with labeled probes representing different regions of the phage genomes are in good agreement. The data obtained strongly confirmed the recombinational origin of the analyzed phages. Thus, all natural transposable phages of P. aeruginosa, including phages from both group B3 and species D3112, were shown to have a recombinational origin. [TOP OF PAGE]

8. Vyiavlenie roli divergentsii v evoliutsii fagov-transpozonov gruppy B3 Pseudomonas aeruginosa [Role of divergence in evolution of group B3 Pseudomonas aeruginosa transposable phage evolution]. Akhverdian, V.Z., Khrenova, E.A., Lobanov, A.O., Krylov, V.N. (1998). Genetika 34:846-849. A heteroduplex analysis was performed to identify and map divergent DNA sequences in the genomes of the P. aeruginosa transposable phages (TPs) of group B3 using different formamide concentrations (30, 50, and 70%). Six PTs were classified into three related species--B3, PM681, and PM57. The role of DNA divergence in the evolution of TPs within one species is insignificant: the genomes of phages pM105 and PM681 (species PM681) and phages Hw12 and pM57 (species pM57) were shown to contain either homologous (98%) or nonhomologous DNA (2%). Homologous, divergent, and nonhomologous DNA regions (modules) were identified in the genomes of the TP of different species. Homologous modules with a level of DNA homology higher than 86% constitute approximately 30% of the phage genome; they are located at the left (1-5 kb) and right (29-38 kb) ends of the phage genome. Divergent modules with a DNA homology level between 50 and 67% and nonhomologous modules represent 30 to 35% and 25 to 30% of the phage genome, respectively. These regions form a mosaic structure in a 5-29-kb region. Thus, the key role of DNA divergence in the evolution of the natural TPs of three related species of group B3 was shown. A single region containing a 5-11-kb divergent DNA sequence was detected in the pM62 phage genome (species pM57). As shown by our previous data, this region was integrated into phage pM62 via interspecific recombination with a phage of species B3. [TOP OF PAGE]

9. Practical use of adapted Salmonella bacteriophage for the treatment and prophylaxis of nosocomial salmonellosis. Akimkin, V.G., Bondarenko, V.M., Voroshilova, N.N., Darbeeva, O.S., Baiguzina, F.A. (1998). Zhurnal Mikrobiologii Epidemiologii i Immunobiologii 85-86. [TOP OF PAGE]

10. Ispol'zovanie adaptirovannogo sal'monelleznogo bakteriofaga v praktike lecheniia i profilaktiki nozokomial'nogo sal'monelleza [Practical use of adapted Salmonella bacteriophage for the treatment and prevention of nosocomial infections]. Akimkin, V.G., Bondarenko, V.M., Voroshilova, N.N., Darbeeva, O.S., Baiguzina, F.A. (1998). Zhurnal Mikrobiologii, Epidemiologii i Immunobiologii 85-86. [TOP OF PAGE]

11. Use of processed solid residue of olive mill products to absorb Escherichia coli and bacteriophage T3 from drinking water. Al-Momani, F., Meqdam, M.M.M., Saadoun, I., Gharaibeh, S.H., Abu-El-Sha'r, W.Y. (1998). Cytobios 95:37-41. The removal of bacteria and viruses from drinking water is of increasing interest particularly if the purification system is inexpensive and readily available. A new material obtained by locally processing the solid residues from olive mill products was investigated as a potential sorbent for removing micro-organisms from drinking water. Indicator micro-organisms, namely Escherichia coli and bacteriophage T3 were used in equilibrium batch mode experiments. Results indicated that the processed solid residue of olive mill products effectively removed 92.8% E. coli and bacteriophage T3 from the water. It is suggested that the olive mill products can be used successfully in treatment of drinking water containing microbial contaminants. [TOP OF PAGE]

12. Polyvirulent rhizobiophage from a soybean rhizosphere soil. Ali, F.S., Hammand, A.M.M., Loynachan, T.E. (1998). Soil Biol. Biochem. 30:2171-2175. [no abstract?]. [TOP OF PAGE]

13. Phage-encoded genes and Salmonella virulence [letter]. Ali, T.R., Pallen, M.J. (1998). Molecular Microbiology 28:1039-1041. [TOP OF PAGE]

14. Bacteriophages show promise as antimicrobial agents. Alisky, J., Iczkowski, K., Rapoport, A., Troitsky, N. (1998). J. Infect. 36:5-15. The emergence of antibiotic-resistant bacteria has prompted interest in alternatives to conventional drugs. One possible option is to use bacteriophages (phage) as antimicrobial agents. We have conducted a literature review of all Medline citations from 1966-1996 that dealt with the therapeutic use of phage. There were 27 papers from Poland, the Soviet Union, Britain and the U.S.A. The Polish and Soviets administered phage orally, topically or systemically to treat a wide variety of antibiotic-resistant pathogens in both adults and children. Infections included suppurative wound infections, gastroenteritis, sepsis, osteomyelitis, dermatitis, empyemas and pneumonia; pathogens included Staphylococcus, Streptococcus, Klebsiella, Escherichia, Proteus, Pseudomonas, Shigella and Salmonella spp. Overall, the Polish and Soviets reported success rates of 80-95% for phage therapy, with rare, reversible gastrointestinal or allergic side effects. However, efficacy of phage was determined almost exclusively by qualitative clinical assessment of patients, and details of dosages and clinical criteria were very sketchy. There were also six British reports describing controlled trials of phage in animal models (mice, guinea pigs and livestock), measuring survival rates and other objective criteria. All of the British studies raised phage against specific pathogens then used to create experimental infections. Demonstrable efficacy against Escherichia, Acinetobacter, Pseudomonas and Staphylococcus spp. was noted in these model systems. Two U.S. papers dealt with improving the bioavailability of phage. Phage is sequestered in the spleen and removed from circulation. This can be overcome by serial passage of phage through mice to isolate mutants that resist sequestration. In conclusion, bacteriophages may show promise for treating antibiotic resistant pathogens. To facilitate further progress, directions for future research are discussed and a directory of authors from the reviewed papers is provided. [TOP OF PAGE]

15. Phage resistance mechanisms in lactic acid bacteria. Allison, G.E., Klaenhammer, T.R. (1998). International Dairy Journal 8:207-226. Dairy fermentations involving Lactococcus lactis and more recently Streptococcus thermophilus, are commonly attacked by bacteriophages. Efforts to protect these dairy starter cultures have resulted in a significant body of knowledge about the bacteriophages, their interactions with the host, and natural phage defense mechanisms that have evolved within bacteria operating under the most dynamic and devastating phage environment faced by industrial fermentations. This paper will overview this area and discuss the novel genetic approaches that are now being investigated in an effort to provide long term phage protection to dairy starter cultures that are used extensively in the industry. [TOP OF PAGE]

16. Microbiological and chemical quality of sludges from domestic wastewater plants. Aulicino, F.A., Colombi, A., Calcaterra, E., Carere, M., Mastrantonio, A., Orsini, P. (1998). International Journal of Environmental Health Research 8:137-144. Digested sludge samples from domestic wastewater treatment plants located in Northern Italy were tested as far as the presence of viruses (enteric viruses and coliphages), bacteria (faecal coliforms, salmonella) and helminth eggs is concerned. Heavy metals were also analysed. Escherichia coli bacteriophages and faecal coliforms were isolated from all samples, while salmonellae and helminth eggs were isolated only from four and three out of 27 total samples, respectively. The 66% of sludge samples, 46 and 82% of aerobic and anaerobic digested sludges respectively, showed the presence of enteric viruses (enteroviruses and reoviruses). The virus concentrations ranged from 0.6 to 123 MPNCU/g. Results of this study suggest that significant concentrations of pathogens such as enteric viruses can be present in digested sludge. which showed compliance with Italian legislation. As suggested by other authors, there is the need for surveillance and reference indications both in EU (European Union) and Italian regulations concerning the use of sludge in agriculture. [TOP OF PAGE]

17. Peptide-guided cancer drugs show promise in mice. Barinaga, M. (1998). Science 279, 323-324. [This Research News item is on drugs developed using phages which were injected into mammalian blood streams. There is only a one sentence reference to the technique, however, and no references cited. Furthermore, the phages did not do any infecting while in the host. Instead, these were phages which displayed peptides on their capsids: "Phages were injected into an animal . . . to identify peptides that stuck to specific tissues."]. [TOP OF PAGE]

18. Induction Studies on Thermophilic Phage. BARRIDGE, B.D. (1998). The University of Nebraska - Lincoln. [TOP OF PAGE]

19. Use of lytic bacteriophage for control of experimental Escherichia coli septicemia and meningitis in chickens and calves. Barrow, P., Lovell, M., Berchieri, A.jr. (1998). Clin. Diag. Lab. Immunol. 5:294-298. A lytic bacteriophage, which was previously isolated from sewage and which attaches to the K1 capsular antigen, has been used to prevent septicemia and a meningitis-like infection in chickens caused by a K1⁺ bacteremic strain of Escherichia coli. Protection was obtained even when administration of the phage was delayed until signs of disease appeared. The phage was able to multiply in the blood. In newly borne colostrum-deprived calves given the E. coli orally, intramuscular inoculation of phage delayed appearance of the bacterium in the blood and lengthened life span. With some provisos there is considerable potential for this approach to bacterial-disease therapy. [TOP OF PAGE]

20. His1, and archaeal virus of the Fuselloviridae family that infects Haloarcula hispanica. Bath, C., Dyall-Smith, M.L. (1998). J. Virol. 72:9392-9395. A novel archaeal virus, His1, was isolated from hypersaline waters in south-eastern Australia. It was lytic, grew only on Ha. hispanica (up to titres of 1011p.f.u./ml), and displayed a "lemon-shaped" morphology (74nm x 44nm) previously reported only for a virus of the extreme thermophiles (SSV1). The density of His1 was approximately 1.28g/ml - similar to that of SSV1 (1.24g/ml). Purified particles were resistant to low salt. The genome was linear, dsDNA and 14.9kb in size, which was similar in size to the genome of the SSV1 (ie. 15.5kb). Morphologically, this isolate clearly belongs to the recently proposed Fuselloviridae family of archaeal viruses. It represents the first member from the extremely halophilic archaea, and its host, Ha. hispanica, is one that can be readily manipulated genetically. [TOP OF PAGE]

21. Molecular evolution of viruses - past and present, Part 2 - An introduction. Becker, Y. (1998). Virus Genes 16:7-11. The evolution of viruses is reviewed within the perspective of the concepts on the evolution of the lipid membrane bound vesicular structures in the prebiotic soup through the ideas on evolution of cells during the RNA World and the transition into the DNA World. The ancient Archeae bacteria and their retrons that carry the bacterial reverse transcriptase gene and their unique protein splicing capability provide an indication of the evolutionary path for retroviruses and, independently, for RNA and DNA viruses of the prokaryotic Archeae bacteria and the eukaryotic yeast and fungi. [TOP OF PAGE]

22. Virus removal from bioproducts using ultrafiltration membranes modified with latex particle pretreatment. Bellara, S.R., Cui, Z., MacDonald, S.L., Pepper, D.S. (1998). Bioseparation 7:79-88. Ultrafiltration is an attractive process for virus removal from bioproducts owing to its high throughput as well as the fact that the operation is carried out under ambient conditions (damage to proteins is highly limited). The principal concern regarding the adoption of conventional ultrafiltration membranes for virus removal is the possibility of the virus passing through abnormally large pores or surface imperfections on the membrane surface. The chief principle behind the present work is to pretreat the membrane by blocking the abnormally large pores using latex particles. Experimental work was conducted to validate this pretreatment using the bacteriophage phi x 174 as a model virus. The results attained were highly encouraging. Different sizes of latex particles were tested by treating a 100 KD molecular weight cut-off membrane, and the transmission of phage (suspended in buffer) through this membrane assessed. In the absence of any particle pretreatment, a virus clearance of 4.78 log reduction value was observed for this membrane. The transmission of phage through the membrane could be reduced by an order of magnitude using 0.11 micron latex particles, or two orders of magnitude using a combination of 0.11 and 0.50 micron particles. The application of latex particles did not hinder the transport of protein through the 100 KD membrane. Protein sieving coefficients obtained using this membrane were 91%, 16% and 2%, for lysozyme, HSA and IgG, respectively. [TOP OF PAGE]

23. Comparison of elimination of bacteriophages MS2 and variant phiX-174 during sewage treatment by natural lagooning or activated sludges: A study on laboratory-scale pilot plants. Benyahya, M., Bohatier, J., Laveran, H., Senaud, J., Ettayebi, M. (1998). Environmental Technology 19:513-519. Using appropriate laboratory pilot plants we studied phage elimination during sewage treatment by lagooning and activated sludges. Sewage fed into two types of pilot plant was seeded with a somatic coliphage (variant phiX-174) or an F-specific RNA phage (MS2). Samples were taken from inside the biological treatment tanks to follow phages disappearance. The kinetics of their elimination were compared with that of an inert tracer, rhodamine B. Other samples were taken at the outflow to evaluate the efficiencies of phage removal for the two treatment processes. The elimination of MS2 in the absence of any specific solid phase was also studied. Results show that rapid adsorption on solid particles was less marked for rhodamine than for the phages. The regression coefficients calculated for MS2 and variant phiX-174 were, respectively, 0.46 day-1 and 0.37 day^-1 for lagooning, and 0.13 h-1 and 0.128 h-1 for activated sludges, whereas those of rhodamine were 0.069 day-1 and 0.024 h^-1. Thus elimination of the phages was faster than that of the tracer. This reflects the influence of factors acting exclusively on the viral particles. The phages do not therefore behave as inert molecules. The efficiencies of removal of the two types of phage were comparable for the two treatment processes. The extent of elimination was of the order of 2 log. The study of the elimination of MS2 in the absence of any specific solid phase showed that the floc of the activated sludges system favoured elimination more than the sediments in the lagooning system. [TOP OF PAGE]

24. Modeling and analysis of a marine bacteriophage infection. Beretta, E., Kuang, Y. (1998). Math. Biosci. 149:57-76. A mathematical model for the marine bacteriophage infection is proposed and its essential mathematical features are analyzed. Since bacteriophage infection induces bacterial lysis which releases into the marine environment, on the average, 'b' viruses per cell, the parameter b epsilon (1, t infinity) or 'virus replication factor' is chosen as the main parameter on which the dynamics of the infection depends. We proved that a threshold b* exists beyond which the endemic equilibrium bifurcates from the free disease one. Still, for increasing b values the endemic equilibrium bifurcates toward a periodic solution. We proved that a compact attractor set omega within the positive cone exists and within omega the free disease equilibrium is globally stable whenever b < or = b*, whereas it becomes a strong uniform repeller for b > b*. A concluding discussion with numerical simulation is then presented. [TOP OF PAGE]

25. Bioluminescence-based assays for detection and characterization of bacteria and chemicals in clinical laboratories. Billard, P., DuBow, M.S. (1998). Clinical Biochemistryy 31:1-14. OBJECTIVES: To survey recent advances in the application of bioluminescence to public health problems. The usefulness of bacterial (lux) and eucaryotic (luc) luciferase genes is presented, along with several examples that demonstrate their value as "reporters" of many endpoints of clinical concern. CONCLUSIONS: The development of new technologies for monitoring biological and chemical contaminants is in continuous progress. Recent excitement in this area has come from the use of genes encoding enzymes for bioluminescence as reporter systems. Applications of the recombinant luciferase reporter phage concept now provide a sensitive approach for bacterial detection, their viability, and sensitivity to antimicrobial agents. Moreover, a number of fusions of the lux and luc genes to stress inducible genes in different bacteria can allow a real-time measurement of gene expression and determination of cellular viability, and also constitute a new tool to detect toxic chemicals and their bioavailability. [TOP OF PAGE]

26. Microscale nutrient patches in planktonic habitats shown by chemotactic bacteria. Blackburn, N., Fenchel, T., Mitchell, J. (1998). Science 282:2254-2256. Are nutrients available to microbial communities in micropatches long enough to influence growth and competition? And what are the sources of such patches? To answer these questions, the swimming behavior of chemotactic bacteria in seawater samples was examined. Clusters of bacteria formed in conjunction with cell lysis and excretion by protozoa. These point sources of nutrients spread into spherical patches a few millimeters in diameter and sustained swarms of bacteria for about 10 minutes. Within that time, a large proportion of the nutrients was encountered by bacteria, chemotactic and nonchemotactic alike. Chemotaxis is adventageous for bacteria using patches over a certain size. [TOP OF PAGE]

27. Transduction of imipenem resistance by wild-type bacteriophages carried by three strains of Pseudomonas aeruginosa isolated from a single source. Blahova, J., Kralikova, K., Krcmery, V., Mlynarcik, D., Trupl, J. (1998). J. Antimicrob. Chemother. 41:660-662. letter (no abstract). [TOP OF PAGE]

28. Two high-frequency-transduction phage isolates from lysogenic strains of Pseudomonas aeruginosa transducing antibiotic resistance. Blahova, J., Kralikova, K., Krcmery, V.Sr., Mikovicova, A., Bartonicova, N. (1998). Acta Virol. 42:175-179. Two high frequency transduction (HFT) phage isolates, obtained from seriously ill patients, transducing individual determinants of antibiotic resistance with a frequency of 10(-5) (phage isolate AP-103) and 10(-6) (phage isolate AP-343), are described. The frequency of transduction depended on the transduced determinant(s) of resistance used for the detection of transductants and on the individual recipient antibiotic-susceptible strain of Pseudomonas aeruginosa (PAO and/or ML series). A multiple-antibiotic resistance was transduced by the phage isolate AP-343 to all tested recipient strains. The appearance of such phages in clinical conditions with an unusually high frequency of transduction might contribute to the dissemination of antibiotic resistance genes among nosocomial strains of P. aeruginosa. The existence of HFT phages might reflect an increased efficiency of transduction of antibiotic resistance among P. aeruginosa strains, and thus an increased risk of spread of antibiotic resistance even to recently introduced anti-pseudomonadal antibiotics among pseudomonads with unfavourable and unwanted epidemiological consequences in hospital conditions. [TOP OF PAGE]

29. Specific assays for bacteria using phage mediated release of adenylate kinase. Blasco, R., Murphy, M.J., Sanders, M.F., Squirrell, D.J. (1998). Journal of Applied Microbiology 84:661-666. [TOP OF PAGE]

30. Response of model microbial communities to increased productivity. Bohannan, B.J.M. (1998). Michigan State Univeristy. [TOP OF PAGE]

31. Human enteric viruses in the water environment: a minireview. Bosch, A. (1998). Int Microbiol 1:191-196. Water virology started around half a century ago, with scientists attempting to detect poliovirus in water samples. Since that time, other enteric viruses responsible for gastroenteritis and hepatitis, among a great variety of virus strains, have replaced enteroviruses as the main target for detection in the water environment. Technical molecular developments, polymerase-chain reaction (PCR) amplification being the method of choice, enable the detection of fastidious health-significant viruses. However, shortcomings of molecular procedures include their potential incompatibility with concentration methods, indispensable to reduce the water sample volume to assay for viruses, the inability to discern between infectious and non infectious material. On the other hand, these procedures are restrained to sophisticated laboratories and detection of alternative indicator organisms has been proposed. Bacterial indicators fail to give a reliable clue of the virological quality of water. Selected bacteriophage groups appear as a better choice for their use as virus indicators. [TOP OF PAGE]

32. Virus production in Phaeocystis pouchetii and its relation to host cell growth and nutrition. Bratbak, G., Jacobsen, A., Heldal, M., Nagasaki, K., Thingstad, T.F. (1998). Aquat. Microb. Ecol. 16:1-9. [TOP OF PAGE]

33. Viral lysis of Phaeocystis pouchetii and bacterial secondary production. Bratbak, G., Jacobsen, A., Heldal, M. (1998). Aquat. Microb. Ecol. 16:11-16. In this experimental study we investigated the effect of viral infection on primary production and carbon now in a phytoplankton-DOC-bacteria food chain during viral lysis of the phytoplankton population. The phytoplankter host-virus system used was Phaeocystis pouchetii (Prymnesiophyceae) and the virus PpV01. Viral infection allowed primary production in the cells to continue throughout most of the lytic cycle. In non-infected algal cultures, net production of DOC and bacterial biomass was low and at the end of the experiment the DOC concentration was 10 to 20%, and the bacterial biomass 0.5 to 4 % of the algal carbon biomass. The amount of DOC released during viral lysis of the algal cells implies that the entire algal biomass was converted to DOG. Growth of bacteria succeeding cell lysis and release of DOC in Virus infected cultures demonstrated that the net effect of the virus infection was an efficient conversion of algal biomass into bacterial biomass. [TOP OF PAGE]

34. Description of two bacteriophages active against Lotus rhizobia. Bruch, C.W., Allen, O.N. (1998). Proc. Am. Soil Sci. Soc. 19:175-??? [TOP OF PAGE]

35. A natural longer glycine-rich region in IKe filamentous phage confers no selective advantage. Bruno, R., Bradbury, A. (1998). Gene 184:121-123. Filamentous phage infect bacteria bearing pili. The phage protein involved in the recognition of pili and subsequent penetration of the phage into bacteria is the gene 3 protein (g3p). This is a multi-domain protein with glycine-rich regions separating some of the domains. Here we have found an insertion within the glycine-rich domain of the g3p of IKe, a filamentous phage which infects bacteria bearing N pili. Although this insertion considerably increases the length of the glycine-rich domain it has no selective advantage or disadvantage in infection or production of phage, and can therefore be considered a neutral mutation. [TOP OF PAGE]

36. Molecular ecology and evolution of Streptococcus thermophilus bacteriophages--a review. Brussow, H., Bruttin, A., Desiere, F., Lucchini, S., Foley, S. (1998). Virus Genes 16:95-109. Bacteriophages attacking Streptococcus thermophilus, a lactic acid bacterium used in milk fermentation, are a threat to the dairy industry. These small isometric-headed phages possess double-stranded DNA genomes of 31 to 45 kb. Yoghurt-derived phages exhibit a limited degree of variability, as defined by restriction pattern and host range, while a large diversity of phage types have been isolated from cheese factories. Despite this diversity all S. thermophilus phages, virulent and temperate, belong to a single DNA homology group. Several mechanisms appear to create genetic variability in this phage group. Site-specific deletions, one type possibly mediated by a viral recombinase/integrase, which transformed a temperate into a virulent phage, were observed. Recombination as a result of superinfection of a lysogenic host has been reported. Comparative DNA sequencing identified up to 10% sequence diversity due to point mutations. Genome sequencing of the prototype temperate phage f Sfi21 revealed many predicted proteins which showed homology with phages from Lactococcus lactis suggesting horizontal gene transfer. Homology with phages from evolutionary unrelated bacteria like E. coli (e.g. lambdoid phage 434 and P1) and Mycobacterium f L5 was also found. Due to their industrial importance, the existence of large phage collections, and the whole phage genome sequencing projects which are currently underway, the S. thermophilus phages may present an interesting experimental system to study bacteriophage evolution. [References: 48]. [TOP OF PAGE]

37. Viral escape from antisense RNA. Bull, J.J., Jacoboson, A., Badgett, M.R., Molineux, I.J. (1998). Molecular Microbiology 28:835-846. RNA coliphage SP was propagated for several generations on a host expressing an inhibitory antisense RNA complementary to bases 31-270 of the positive-stranded genome. Phages evolved that escaped inhibition. Typically, these escape mutants contained 3-4 base substitutions, but different sequences were observed among different isolates. The mutations were located within three different types of structural features within the predicted secondary structure of SP genomic RNA: (i) hairpin loops; (ii) hairpin stems; and (iii) the 5' region of the phage genome complementary to the antisense molecule. Computer modelling of the mutant genomic RNAs showed that all of the substitutions within hairpin stems improved the Watson-Crick pairing of the stem. No major structural rearrangements were predicted for any of the mutant genomes, and most substitutions in coding regions did not alter the amino acid sequence. Although the evolved phage populations were polymorphic for substitutions, many substitutions appeared independently in two selected lines. The creation of a new, perfect, antisense RNA against an escape mutant resulted in the inhibition of that mutant but not of other escape mutants nor of the ancestral, unevolved phage. Thus, at least in this system, a population of viruses that evolved to escape from a single antisense RNA would require a cocktail of several antisense RNAs for inhibition. [TOP OF PAGE]

38. Occurrence of male-specific bacteriophage in feral and domestic animal wastes, human feces, and human-associated
    wastewaters. Calci, K.R., Burkhardt, W.3., Watkins, W.D., Rippey, S.R. (1998). Appl. Environ. Microbiol. 64:5027-5029. Male-specific bacteriophage (MSB) densities were determined in animal and human fecal wastes to assess their potential impact on aquatic environments. Fecal samples (1,031) from cattle, chickens, dairy cows, dogs, ducks, geese, goats, hogs, horses, seagulls, sheep, and humans as well as 64 sewerage samples were examined for MSB. All animal species were found to harbor MSB, although the great majority excreted these viruses at very low levels. The results from this study demonstrate that in areas affected by both human and animal wastes, wastewater treatment plants are the principal contributors of MSB to fresh, estuarine, and marine waters. [TOP OF PAGE]

39. Search for bacteriophages spontaneously occurring in cultures of haemolytic intestinal spirochaetes of human and animal origin. Calderaro, A., Dettori, G., Grillo, R., Plaisant, P., Amalfitano, G., Chezzi, C. (1998). Journal of Basic Microbiology 38:313-322. An electron microscopic survey of the occurrence of bacteriophages which appear spontaneously in cultures of haemolytic intestinal spirochaetes of human and animal origin was made. Excluding one isometric tailed phage particle which was observed in the form of free particle in proximity to a spirochaete of the w beta HIS strain HRM18, bacteriophages were never observed while examining cells of 21 weakly beta-haemolytic human intestinal spirochaetes (w beta HIS), swine Serpulina pilosicoli strain P43/6/78, and the avian strain 1380, although 50-100 cells of each spirochaetal strain were analysed. Isometric tailed bacteriophages were found associated with only three out of the 100 cells of strongly beta-haemolytic swine Serpulina hyodysenteriae strain P18A comparatively analysed. According to our results and previous published reports, the occurrence of bacteriophages which appear spontaneously in cultures of intestinal spirochaetes is a rare event. [TOP OF PAGE]

40. Bacteriophages induced from weakly beta-haemolytic human intestinal spirochaetes by mitomycin C. Calderaro, A., Dettori, G., Collini, L., Ragni, P., Grillo, R., Cattani, P., Fadda, G., Chezzi, C. (1998). Journal of Basic Microbiology 38:323-335. A comparative electron microscopic analysis of weakly beta-haemolytic spirochaetes related to human and animal intestinal spirochaetosis was done in order to search for the presence of inducible bacteriophages associated with these spirochaetes. Bacteriophages were detected at the electron microscope after experimental induction with mitomycin C in 4 strains of weakly beta-haemolytic spirochaetes related to human intestinal spirochaetosis, in Serpulina pilosicoli strain P43/6/78, the causative agent of swine intestinal spirochaetosis, in a spirochaetal strain related to avian intestinal spirochaetosis, and in Serpulina hyodysenteriae, strain P18A, the causative agent of swine dysentery, which was comparatively analysed as control. All phage-particles observed in both human and animal intestinal spirochaetes were morphologically similar with an isometric head of 45 nm diameter and a tail 63-70 nm long and 7-12 nm width. The presence of morphologically similar phages in all the haemolytic intestinal spirochaetes of human and animal origin analysed in this study opens some important questions, about the genetic relationship of phages present in pathogenic intestinal spirochaetes, their host range, and the possibility of natural gene transfer among pathogenic haemolytic intestinal spirochaetes of human and animal origin. [TOP OF PAGE]

41. Fecal coliform-related bacterial and coliphage populations in five lakes of southeastern Spain. Calvo, C., Gomez, M.A., Gonzalez-Lopez, J. (1998). Microbiological Research 153:283-288. Aerobic heterotrophic bacteria, fecal and total coliforms, fecal streptococci and coliphages were isolated from five protected lakes in the Antequera area of Spain over the time from January to March (1994-96). The water samples contained large number of heterotrophic bacteria (mean counts 0.2 to 5.0 x 10(7) cfu per 100 ml). Most of the lakes contained fecal streptococci and a relationship between streptococci and salinity of the water samples was established. Coliphages were isolated from lakes containing fecal coliform and these bacteria were taxonomically identified as E. coli. Coliform bacilli do not seem to be an adequate indicator of fecal pollution for these ephemeral small lakes. [TOP OF PAGE]

42. The pleasures of pond scum. Carlson, S. (1998). Scientific American March, 96-98. [TOP OF PAGE]

43. New cholera phages for Vibrio cholerae serovar O139. Chakrabarti, A.K., Ghosh, A.N., Sarkar, B.L. (1998). J. Infect. 36:131-132. [TOP OF PAGE]

44. The bacteriophages. Champagne, C.P., Moineau, S. (1998). pp. 89-116. In In Champagne, C.P. (ed.), Production of Dairy Starter Cultures (in French). [TOP OF PAGE]

45. Filamentous bacteriophages of Vibrio parahaemolyticus as a possible clue to genetic transmission. Chang, B., Taniguchi, H., Miyamaoto, H., Yoshida, S.I. (1998). J. Bacteriol. 180:5094-5101. We have previously reported the isolation and characterization of two filamentous bacteriophages of Vibrio parahaemolyticus, designated Vf12 and Vf33. In this study, to understand the potential of these phages as tools for genetic transmission, we investigated the gene structures of replicative-form (RF) DNAs of their genomes and the distribution of these DNAs on chromosomal and extrachromosomal DNAs. The 7,965-bp nucleotide sequences of Vf12 and Vf33 were determined. An analysis of the overall gene structures revealed that Vf12 and Vf33 had conserved regions and distinctive regions. The gene organization of their conserved regions was similar to that of CTX phage of Vibrio cholerae and coliphage Ff of Escherichia coli, while their distinctive regions were characteristic of Vf12 and Vf33 phage genomes. Southern blot hybridization testing revealed that the filamentous phage genomes integrated into chromosomal DNA of V. parahaemolyticus at the distinctive region of the phage genome and were also distributed on some plasmids of V. parahaemolyticus and total cellular DNAs of one Vibrio damsela and one nonagglutinable Vibrio strain tested. These results strongly suggest the possibilities of genetic interaction among the bacteriophage Vf12 and Vf33 genomes and chromosomal and plasmid-borne DNAs of V. parahaemolyticus strains and of genetic transmission among strains through these filamentous phages. [TOP OF PAGE]

46. The use of affinity adsorbents in expanded bed adsorption. Chase, H.A. (1998). Journal of Molecular Recognition 11:217-221. The potential for the use of affinity ligands in expanded bed adsorption (EBA) procedures is reviewed. The use of affinity ligands in EBA may improve its use in direct recovery operations, as the enhanced selectivity of the adsorbent permits selective capture of the target from complex feedstocks and high degrees of purification. The properties of ligands suitable for use in EBA processes are identified and illustrated with examples. In addition to its use in the recovery of soluble products, such as proteins and nucleic acids, from particulate feedstocks, EBA can also be used to recover particulate entities, such as cells and packaged DNA (viruses and phages), from feedstocks. Affinity ligands coupled to appropriate chosen support materials will be required for such processes in order to achieve the necessary selectivity for the required particulate entity. The latter point is illustrated by the use of proteinaceous ligands immobilized to perfluorocarbon emulsions to achieve separations of microbial cells. [TOP OF PAGE]

47. The fate and transport of viruses through surface water constructed wetlands. Chendorian, M., Yates, M., Villegas, F. (1998). Journal of Environmental Quality 27:1451-1458. Coliphage removal efficiency and the effects of wetland hydrology on virus transport were determined for constructed wetlands in San Jacinto, CA. Mathematical models were used to further characterize virus transport. MS2, an F-specific RNA (FRNA) coliphage was used as a model for human enteric viral behavior. Two wetland types were studied, a one-phase cell and three-phase cell. These wetlands received unchlorinated secondary effluent at a constant rate. The mean residence time in the wetlands was 9 +- 3 d as determined using bromide as a conservative tracer. Assuming 100% porosity, a plug flow model predicts this mean residence time within the experimental standard deviation (8 d). This suggests that a negligible volume was occupied by vegetation and settled solids. The convection-dispersion equation adequately simulated the residence time distribution of the conservative tracer. MS2 removal in the wetlands was experimentally determined to be 97 +- 3%. There was no distinction between the two wetland types in terms of removal efficiency. The average coliphage decay rate was calculated to be 0.44 per day. However, the error involved with using the first order decay rate was high, 83 +- 12%. Therefore, first order decay does not adequately describe removal processes within the wetland. Most virus removal occurred within the first 3 m (k = 4.0 +- 1.8 d-1) with a removal efficiency of 85.3 +- 0.6%. The remainder had a decay rate of 0.20 +- 0.17 d-1 with a removal efficiency of 56 +- 33%. [TOP OF PAGE]

48. Lysogenic bacteriophage M1 from Selenomonas ruminantium: isolation, characterization and DNA sequence analysis of the integration site. Cheong, J.P., Brooker, J.D. (1998). Microbiology 144:2195-2202. Bacteriophage M1 from the ruminal bacterium Selenomonas ruminantium strain ML12 comprises a 30 nm icosahedral capsid, a 25 nm tail and 48 kb of linear dsDNA with cohesive ends. A restriction map of the phage genome has been constructed. The presence of bacteriophage M1 in the rumen has been demonstrated by PCR amplification and Southern blot analysis of DNA from rumen bacterial samples obtained from ten different sheep. Lysogeny was demonstrated by hybridization of M1 DNA to host chromosomal DNA and by identification and cloning of a 2.3 kb region of the phage containing the predicted attP domain which promotes chromosomal integration. DNA sequencing of the attP region demonstrated two major ORFs surrounding the predicted attP site and structural analysis of this region revealed a motif comprising three different inverted repeats surrounding a 12 bp palindrome. Analysis of the translated amino acid sequence upstream of the attP site demonstrated the presence of conserved residues found within integrase proteins of several temperate phages of different bacterial species. [TOP OF PAGE]

49. Virus-like particles in microbial population control and horizontal gene transfer in the aquatic environment. Chiura, H.X., Velimirov, B., Kogure, K. (1998). p. ???-??? In Bell, C.R., Brylinsky, M., and Johnson-Green, P. (eds.), Proceedings of the Eighth International Symposium on Microbial Ecology. Atlantic Canada Society for Microbial Ecology, Halifax, Canada. [TOP OF PAGE]

50. Gene transfer mediated by virus of novel thermophilic bacteria in hot spring sulfur-turf microbial mats. Chiura, H.X., Kato, K., Hiraishi, A., Maki, Y. (1998). p. 124?? In Bell, C.R., Brylinsky, M., and Johnson-Green, P. (eds.), Proceedings of the Eighth International Symposium on Microbial Ecology. Atlantic Canada Society for Microbial Ecology, Halifax, Canada. [TOP OF PAGE]

51. Bacteriophages and bacteria as indicators of enteric viruses in oysters and their harvest waters. Chung, H., Jaykus, L.A., Lovelace, G., Sobsey, M.D. (1998). Water Science and Technology 38:37-44. Reliable indicators are needed to detect enteric virus contamination of bivalve molluscan shellfish and their harvest waters. Concentrations of male-specific (F+) coliphages, Bacteroides fragilis phages, Salmonella phages and several indicator bacteria in wastewater, estuarine receiving water and its oysters were examined for their ability to predict the presence and levels of faecal contamination and enteric viruses in oysters. Enteric viruses in oysters were detected by cell culture and RT-PCR methods. F+ coliphages, Salmonella phages, B. fragilis phages and faecal indicator bacteria (faecal coliforms, E. coli, enterococci and Clostridium perfringens) were generally positively associated and were highest in raw sewage and progressively lower in sewage effluent and in receiving waters at increasing distance from the wastewater discharge. Indicator levels in oysters were highest for F+ coliphages and C. perfringens. One F+ RNA coliphage serotype (Group II) predominated in the wastewater, receiving water and oysters. Human enteric viruses were detected in 17/31 oyster samples. The levels of most indicators in oysters and water were higher when oysters were enteric virus-positive and lower when oysters were enteric virus-negative. F+ coliphages and C. perfringens were the only indicators significantly associated with the presence of enteric viruses in oysters. F+ coliphages and their serotypes are promising indicators of human enteric virus contamination in oysters and their harvest waters. [TOP OF PAGE]

52. Virus particle production in lysogenic bacteria exposed to protozoan grazing. Clarke, K.J. (1998). FEMS Microbiol. Let. 166:177-180. Electron microscopy was used to investigate the apparent induction of virus particle production in bacteria undergoing digestion by ciliates. Results showed that numbers of bacteria containing virus particles increased by a factor of 25 when enclosed within ciliate food vacuoles. It was also found that 10% of these particles survived the digestion process to be released back into the aquatic habitat within faecal pellets. The possibility of virus gene transfer occurring between lysogenically infected bacteria that survive the ciliate digestive processes, is also considered. [TOP OF PAGE]

53. Removal of waterborne human enteric viruses and coliphages with oxidized coal. Cloete, T.E., Da, S.E., Nel, L.H. (1998). Current Microbiology 37:23-27. Human enteric viruses and coliphages have been detected in water that has undergone what is generally considered adequate treatment, including chlorination. Because small numbers of virus particles are needed for the initiation of a productive virus infection, the presence of any number of virus particles in water resources will always be of concern. In this investigation the ability of oxidized coal to remove viruses from water was investigated. The oxicoal product was found to be able to remove not only coliphages, but also various pathogenic human viruses from seeded water sources. Removal was dependent upon the type of virus, the period of exposure, and the concentration of oxidized coal. [TOP OF PAGE]

54. Prophage induction of indigenous marine lysogenic bacteria by environmental pollutants. Cochran, P.K., Kellogg, C.A., Paul, J.H. (1998). Mar. Ecol. Prog. Ser. 164:124-133. Lysogenic bacteria may be abundant components of bacterial assemblages in marine waters. The tremendous number of viruses found in estuarine and other eutrophic environments may be the result in part of induction of prophages. Mitomycin C is the inducing agent of choice for prophage induction; however this is not naturally found in the marine environment. We determined the capability of environmentally important pollutants to effect prophage induction in natural populations of marine bacteria. We investigated Aroclor 1248, a PCB mixture, bunker C fuel oil No. 6, and a pesticide mixture as inducing agents for natural bacterial communities from the Gulf of Mexico. Mitomycin C was also employed as a positive control for induction. Induction was determined as a significant increase in viral direct counts compared to control and ranged from 149 to 1336% of the controls. Two-thirds of the environments sampled showed prophage induction by one of the methods utilized, with the PCB mixture and Aroclor 1248 giving the highest percent efficiency (75%) of induction. This study shows that many environmentally important pollutants may be inducing agents for natural lysogenic viral production in the marine environment. [TOP OF PAGE]

55. Seasonal abundance of lysogenic bacteria in a subtropical estuary. Cochran, P.K., Paul, J.H. (1998). Appl. Environ. Microbiol. 64:2308-2312. Seasonal changes in the abundance of inducible lysogenic bacteria in a eutrophic estuarine environment were investigated over a 13-month period. Biweekly water samples were collected from Tampa Bay, Fla., and examined for prophage induction by mitomycin C treatment. At the conclusion of the study, we determined that 52.2% of the samples displayed prophage induction, as indicated by significant increases in viral direct counts compared with uninduced controls. Samples that displayed prophage induction occurred during the warmer months (February through October), when surface water temperatures were above 19 degree C, and no induction was observed in November, December, or January. This study presents clear evidence that there is seasonal variation in the number of inducible lysogenic bacteria in an estuarine environment. [TOP OF PAGE]

56. Increasing phage resistance of cheese starters: A case study using Lactococcus lactis DPC4268. Coffey, A., Coakley, M., McGarry, A., Fitzgerald, G.F., Ross, R.P. (1998). Letters in Applied Microbiology 26:51-55. This study serves as an example of strategies used to increase the phage resistance of an important Irish Cheddar cheese starter, Lactococcus lactis DPC4268. It describes the emergence and persistence of a lytic bacteriophage, 4268, that has a relatively large burst size and exhibits no homology to the most common phage types encountered in Irish cheese plants. Inherent difficulties were encountered that prevented the effective introduction of conjugative phage-resistance plasmids pNP40 and pMRCO1 to strain DPC4268. In fact, pNP40-associated Abi systems were naturally present in six of 19 starters. Control of phage 4268 was eventually achieved by generating a mutant of DPC4268, which was subsequently used for cheese manufacture. [TOP OF PAGE]

57. Increasing the phage resistance of cheese starter Lactococcus lactis DPC4268 in response to the emergence of a novel highly virulent phage in industry. Coffey, A., Coakley, M., McGarry, A., Fitzgerald, G.F., Ross, R.P. (1998). pp. 460-481. In In ??? (ed.), Actes du Colloque LACTIC-97 Lactic Acid Bacteria: Which strains? For which products? Villers Bocage, Cedex, France. [TOP OF PAGE]

58. Effect of Environmental Factors upon a Staphylococcus Host-Phage System. Countryman, J.L. (1998). Stanford University. [TOP OF PAGE]

59. Technological and health benefits of dairy starter cultures. Daly, C., Fitzgerald, G.F., O'Connor, L., Davis, R. (1998). International Dairy Journal 8:195-205. Lactic acid bacteria are the focus of research efforts world-wide because of their central role in commercially important dairy fermentations. Significant advances have been made in elucidating the genetic, biochemical and physiological basis of many of the key technological traits of these bacteria. This review examines the recent progress that has been made in the areas of bacteriophage resistance, bacteriocins, proteolysis and carbohydrate metabolism, in the light of their industrial applications. In addition, the increasingly important role of lactic acid bacteria in the production of probiotic products and their potential as vaccine delivery vehicles are discussed. [TOP OF PAGE]

60. Virulence of phage populations infecting Halobacterium cutirubrum. Daniels, L.L., Wais, A.C. (1998). FEMS Microbiol. Ecol. 25:129-134. Phages of low virulence predominated culturable phage populations in a naturally occurring Jamaican salt pond with Halobacterium cutirubrum as host. These mutated rapidly in culture to higher virulence due to more rapid adsorption to host cells. Wild-type phages of low virulence, S50.2 and S41, with adsorption rate constants (K) of 1.15 and 1.21 times 10^-11 ml min^-1 mutated to produce highly virulent derivatives S50.2Vm and S41Vm with K= 2.60 and 2.61 times 10^-11 ml min-1, values similar to the most virulent wild-type phages S5100 and S4100, K= 2.61 and 2.55 times 10^-11 ml min^-1 respectively. Quantitative measures of intracellular phage development were constant among low and high virulence wild-type and mutant phages S50.2, S5100 and S50.2Vm with eclipse periods of 5.5 h, latent periods of 9 h and average apparent burst sizes of 60-65. We propose that the natural environment may select for slow adsorption to reduce the frequency of release of DNA from phage particles in response to encounters with non-host material. [TOP OF PAGE]

61. Coliphage prevalence in high school septic effluent and associated ground water. DeBorde, D.C., Woessner, W.W., Lauerman, B., Ball, P. (1998). Water Res. 32:3781-3785. At the present time, somatic and male-specific coliphage and human enterovirus groups are being considered as indicators of possible pathogenic human enteric virus contamination from fecal contamination. A primary attribute for any indicator of fecal contamination is its prevalence at the source and in associated ground water. It must be consistently found in the source material at concentrations that are measurable with available techniques. Over a period of ten months, male-specific and somatic coliphage ranged from apprx7000 to apprx4,000,000 PFU/L in the effluent from a multi-user septic-tank. Unlike the values determined for septic-tank effluent, coliphage concentrations measured in ground water over this same period only varied by five-fold. Coliphage concentration in ground water under the down-gradient edge of the drainfield contained apprx1000 PFU/L. This concentration decreased at -1 log10/5 m during 17.4 m of ground-water transport. From these data, coliphage concentrations in septic-tank effluent seem sufficient to allow their use as indicators of fecal contamination in ground water. [TOP OF PAGE]

62. Virus occurrence and transport in a school septic system and unconfined aquifer. DeBorde, D.C., Ball, P.N., Lauerman, B., Woessner, W.W. (1998). Ground Water 36:825-834. Federal efforts to establish reliable natural disinfection criteria for ground water supplies require the identification of appropriate indicator viruses to represent pathogenic viruses and an understanding of parameters affecting virus survival and transport in a variety of hydrogeologic settings. A high school septic system and the associated fecal waste-impacted unconfined sand and gravel aquifer were instrumented to: (1) evaluate if the concentrations of enterovirus and coliphage in this system were sufficient to allow their use as indicator viruses; (2) establish viral transport rates, transport distances, and concentrations in a highly conductive cold water aquifer. Enteroviruses were found in only two of eight assays of the septic tank effluent (0.26 and 4.4 virus/L) and were below detection in eight ground water samples. Male-specific and somatic coliphage were detectable in both the septic tank effluent (averaging 674,000 and 466,000 coliphage/L, respectively) and in the impacted underlying ground water, decreasing to detection limits beyond 38 m of the drainfield. Virus transport parameters in this aquifer were measured by seeding high numbers of MS2 and OX174 coliphage into the ground water and documenting their transport over 17.4 m. A portion of the seeded virus traveled at least as fast as the bromide tracer (1 to 2.9 m/d). Proposed natural disinfection criteria would not be met in this aquifer using standard 30.5 m setback distances. In addition, the virus sorption processes and long survival times resulted in presence of viable seed virus for more than nine months. [TOP OF PAGE]

63. Phages infecting Vibrio vulnificus are abundant and diverse in oysters (Crassostrea virginica) collected from the Gulf of Mexico. Depaola, A., Motes, M.L., Chan, A.M., Suttle, C.A. (1998). Appl. Environ. Microbiol. 64:346-351. Phages infecting Vibrio vulnificus were abundant (10^-4 phages g of oyster tissue^-1) throughout the year in oysters (Crassostrea virginica) collected from estuaries adjacent to the Gulf of Mexico (Apalachicola Bay, Fla.; Mobile Bay, Ala.; and Black Bay, La.). Estimates of abundance ranged from 10^-1 to 10^-5 phages g of oyster tissue^-1 and were dependent on the bacterial strain used to assay the sample. V. vulnificus was near or below detection limits ( lt 0.3 cell g^-1) from January through March and was most abundant (10^-3 to 10^-4 cells g^-1) during the summer and fall, when phage abundances also tended to be greatest. The phages isolated were specific to strains of V. vulnificus, except for one isolate that caused lysis in a few strains of V. parahaemolyticus. Based on morphological evidence obtained by transmission electron microscopy, the isolates belonged to the Podoviridae, Styloviridae, and Myoviridae, three families of double-stranded DNA phages. One newly described morphotype belonging to the Podoviridae appears to be ubiquitous in Gulf Coast oysters. Isolates of this morphotype have an elongated capsid (mean, 258 nm; standard deviation, 4 nm; n = 35), with some isolates having a relatively broad host range among strains of V. vulnificus. Results from this study indicate that a morphologically diverse group of phages which infect V. vulnificus is abundant and widely distributed in oysters from estuaries bordering the northeastern Gulf of Mexico. [TOP OF PAGE]

64. Evolution of Streptococcus thermophilus bacteriophage genomes by modular exchanges followed by point mutations and small deletions and insertions. Desiere, F., Lucchini, S., Brussow, H. (1998). Virology 241:345-356. Comparative sequence analysis of 40 % of the genomes from two prototype Streptococcus thermophilus bacteriophages (lytic group I phage fSfi19 and the cos-site containing temperate phage fSfi21) suggested two processes in the evolution of their genomes. In a first evolutionary distant phase the basic genome structure was apparently constituted by modular exchanges. Over the 17 kb long DNA segment analyzed in the present report we observed clusters of genes with similarity to genes from Leuconostoc oenos phage L10, Lactococcus lactis phage BK5-T and Streptococcus pneumoniae phage Dp-1. A chimeric protein was predicted for orf 1291 which showed similarity both to phage BK5-T and phage Dp-1. The very large orf 1626 gene product showed similarity to two adjacent genes from the Lactobacillus delbrueckii phage LL-H and further phage proteins (Lactococcus lactis, Bacillus subtilis). The similarities were localized to distinct parts of this apparently multifunctional protein. The putative fSfi19 lysin showed similarity both to lysins of phages and cellular enzymes. In a second evolutionary more recent phase the S. thermophilus phage genomes apparently diversified by point mutations and small deletions/insertions. Over the investigated 17 kb DNA region fSfi19 differed from fSfi21 by 10 % base pair changes, the majority of which were point mutations (mainly at the third codon position), while a third of the bp differences were contributed by small deletions/insertions. The bp changes were unevenly distributed: Over the Leuconostoc phage-related DNA the change rate was high, while over the Lactococcus and S. pneumoniae phage-related DNA the change rate was low. We speculate that the degree of bp changes could provide relative time scales for the modular exchange reactions observed in S. thermophilus phages. [TOP OF PAGE]

65. A leucine repeat motif in AbiA is required for resistance of Lactococcus lactis to phages representing three species. Dinsmore, P.K., O'Sullivan, D.J., Klaenhammer, T.R. (1998). Gene 212:5-11. The abiA gene encodes an abortive bacteriophage infection mechanism that can protect Lactococcus species from infection by a variety of bacteriophages including three unrelated phage species. Five heptad leucine repeats suggestive of a leucine zipper motif were identified between residues 232 and 266 in the predicted amino acid sequence of the AbiA protein. The biological role of residues in the repeats was investigated by incorporating amino acid substitutions via site-directed mutagenesis. Each mutant was tested for phage resistance against three phages, phi 31, sk1, and c2, belonging to species P335, 936, and c2, respectively. The five residues that comprise the heptad repeats were designated L234, L242, A249, L256, and L263. Three single conservative mutations of leucine to valine in positions L235, L242, and L263 and a double mutation of two leucines (L235 and L242) to valines did not affect AbiA activity on any phages tested. Non-conservative single substitutions of charged amino acids for three of the leucines (L235, L242, and L256) virtually eliminated AbiA activity on all phages tested. Substitution of the alanine residue in the third repeat (A249) with a charged residue did not affect AbiA activity. Replacement of L242 with an alanine elimination phage resistance against phi 31, but partial resistance to sk1 and c2 remained. Two single proline substitutions for leucines L242 and L263 virtually eliminated AbiA activity against all phages, indicating that the predicted alpha-helical structure of this region is important. Mutations in an adjacent region of basic amino acids had various effects on phage resistance, suggesting that these basic residues are also important for AbiA activity. This directed mutagenesis analysis of AbiA indicated that the leucine repeat structure is essential for conferring phage resistance against three species of lactococcal bacteriophages. [TOP OF PAGE]

66. E. coli's double life. Dixon, B. (1998). ASM News 64:616-617. [TOP OF PAGE]

67. The development of management strategies for control of virological quality in oysters. Dore, W.J., Henshilwood, K., Lees, D.N. (1998). Water Science and Technology 38:29-35. This laboratory has previously described the development of a PCR method for the detection of small round structured viruses (SRSVs) in shellfish and the use of male-specific RNA bacteriophages as "viral" indicators to predict the occurrence and behaviour of such viruses in shellfish. We now describe the application of these procedures to monitor oyster harvesting areas, shellfish treatment processes and products sold to the consumer. Oysters are traditionally consumed raw and can be treated to enable them to meet the legislative end-product standard of < 0.4), correlations with all microbiological parameters. Somatic coliphages also revealed highly significant (0.32 < r < 0.66) correlations (P = < 0.33). The equations obtained using a multiple regression analysis with a view to predicting microbiological, viral, and Salmonella indicator density demonstrated that environmental variables facilitate the construction of highly significant equations, but that these have low predictive capability (R2 = < 5 mg/L iodine doses, losing 6 logs (99.9999%) of infectivity within less than 3 min contact time. The effect of pH on MS2 inactivation within the range of 6 to 8 was not statistically significant. However, in the presence of dissolved organic substances, such as detergents and proteins, the inactivation of MS2 viruses decreased significantly to less than 4 logs (99.99%). Of special interest was that in the presence of beef extract proteins, an apparent reversal of MS2 inactivation, dubbed rebound, was observed. It was observed that after an initial 5 to 6 log reduction in infectivity, a consistent and statistically significant increase in the number of plaque forming units (PFU), as much as 2 logs, was measured. MS2 rebound occurred only when the oxidized iodine residual had been quickly consumed by beef extract proteins in solution. Neither virus particle aggregation nor water salinity were found to account for the increase in PFU values. Based on other investigators' suggestions that iodine disinfection caused changes to viral protein coats, it was hypothesized that conformational changes in MS2's protein coat caused by iodine would result in a change in the isoelectric focusing point of whole MS2 virions. A shift in isoelectric focusing point from an acidic pH value of 3.9 to more basic values, and a dispersion of the virus band after exposure to high levels of iodine was observed, supporting the hypothesis that iodine caused changes in the charge distribution characteristics of the protein coat. [TOP OF PAGE]

68. Sequence and analysis of the 60 kb conjugative, bacteriocin-producing plasmid pMRC01 from Lactococcus lactis DPC3147. Dougherty, B.A., Hill, C., Weidman, J.F., Richardson, D.R., Venter, J.C., Ross, R.P. (1998). Molecular Microbiology 29:1029-1038. The complete sequence of pMRC01, a large conjugative plasmid from Lactococcus lactis ssp. lactis DPC3147, has been determined. Using a shotgun sequencing approach, the 60,232 bp plasmid sequence was obtained by the assembly of 1056 underlying sequences (sevenfold average redundancy). Sixty-four open reading frames (ORFs) were identified. Analysis of the gene organization of pMRC01 suggests that the plasmid can be divided into three functional domains, with each approximately 20 kb region separated by insertion sequence (IS) elements. The three regions are (i) the conjugative transfer region, including a 16-gene Tra (transfer) operon; (ii) the bacteriocin production region, including an operon responsible for the synthesis of the novel bacteriocin lacticin 3147; and (iii) the phage resistance and plasmid replication region of the plasmid. The complete sequence of pMRC01 provides important information about these industrially relevant phenotypes and gives insight into the structure, function and evolution of large gram-positive conjugative plasmids in general. The completely sequenced pMRC01 plasmid should also provide a useful framework for the design of novel plasmids to be incorporated into starter strain improvement programmes for the dairy industry. [TOP OF PAGE]

69. Delineating the specific influence of virus isoelectric point and size on virus adsorption and transport through sandy soils. Dowd, S.E., Pillai, S.D., Wang, S., Corapcioglu, M.Y. (1998). Appl. Environ. Microbiol. 64:405-410. Many of the factors controlling viral transport and survival within the subsurface are still poorly understood. In order to identify the precise influence of viral isoelectric point on viral adsorption onto aquifer sediment material, we employed five different spherical bacteriophages (MS2, PRD1, Q beta, phi X174, and PM2) having differing isoelectric points (pI 3.9, 4.2, 5.3, 6.6, and 7.3 respectively) in laboratory viral transport studies. We employed conventional batch flowthrough columns, as well as a novel continuously recirculating column, in these studies. In a 0.78-m batch flowthrough column, the smaller phages (MS2, phi X174, and Q beta), which had similar diameters, exhibited maximum effluent concentration/initial concentration values that correlated exactly with their isoelectric points. In the continuously recirculating column, viral adsorption was negatively correlated with the isoelectric points of the viruses. A model of virus migration in the soil columns was created by using a one-dimensional transport model in which kinetic sorption was used. The data suggest that the isoelectric point of a virus is the predetermining factor controlling viral adsorption within aquifers. The data also suggest that when virus particles are more than 60 nm in diameter, viral dimensions become the overriding factor. [TOP OF PAGE]

70. Rates of spontaneous mutation. Drake, J.W., Charlesworth, B., Charlesworth, D., Crow, J.F. (1998). Genetics 148:1667-1686. [TOP OF PAGE]

71. Effectiveness of membrane-filtration for phage technique for the detection of Xanthomonas campestris pv. citri. Ebisugi, H., Ooishi, S., Goda, T., Kubo, H., Sakiyama, K. (1998). Research Bulletin of the Plant Protection Service Japan 113-115. The plaque count method test for the detection of Xanthomonas campestris pv. citri was reexamined. The membrane-filter (pore size 0.22 mum) was used after centrifugation process of test solution in the phage count method in order to exclude the contaminated bacteria in phage suspension. The use of membrane filter was effective in plaque-counting. [TOP OF PAGE]

72. Evolutionary dynamics of fitness recovery from the debilitating effects of Muller's ratchet. Elena, S.F., Davila, M., Novella, I.S., Holland, J.J., Domingo, E., Moya, A. (1998). Evolution 52:309-314. The great adaptability shown by RNA viruses is a consequence of their high mutation rates. The evolution of fitness in a severely debilitated, clonal population of the nonsegmented ribovirus vesicular stomatitis virus (VSV) has been compared under five different demographic regimes, ranging from severe serial bottleneck passages tone virion) to large population passages (10(6) virions or more) under similar environmental conditions (cell culture type and temperature). No matter how small the bottleneck, the fitness of the evolved populations was always higher than the fitness of the starting population; this result is clearly different from that previously reported for viruses with higher fitness. The reattainment of fitness under a regime of serial population passages showed two main characteristics: (1) the rate of adaptation was higher during early passages; and (2) a maximum fitness value was reached after a large number of passages. The maximum fitness reached by this initially debilitated clone was similar to the fitness of wild-type virus. The practical implications of these findings in the design of vaccines using attenuated viruses are also discussed. [TOP OF PAGE]

73. AbiQ, an abortive infection mechanism from Lactococcus lactis. Emond, E., Dion, E., Walker, S.A., Vedamuthu, E.R., Kondo, J.K., Moineau, S. (1998). Appl. Environ. Microbiol. 64:4748-4756. Lactococcus lactis W-37 is highly resistant to phage infection. The cryptic plasmids from this strain were coelectroporated, along with the shuttle vector pSA3, into the plasmid-free host L. lactis LM0230. In addition to pSA3, erythromycin- and phage-resistant isolates carried pSRQ900, an 11-kb plasmid from L. lactis W-37. This plasmid made the host bacteria highly resistant (efficiency of plaquing <10^-8) to c2- and 936-like phages. pSRQ900 did not confer any resistance to phages of the P335 species. Adsorption, cell survival, and endonucleolytic activity assays showed that pSRQ900 encodes an abortive infection mechanism. The phage resistance mechanism is limited to a 2.2-kb EcoRV/BclI fragment. Sequence analysis of this fragment revealed a complete open reading frame (abiQ), which encodes a putative protein of 183 amino acids. A frameshift mutation within abiQ completely abolished the resistant phenotype. The predicted peptide has a high content of positively charged residues (pI = 10.5) and is, in all likelihood, a cytosolic protein. AbiQ has no homology to known or deduced proteins in the databases. DNA replication assays showed that phage c21 (c2-like) and phage p2 (936-like) can still replicate in cells harboring AbiQ. However, phage DNA accumulated in its concatenated form in the infected AbiQ⁺ cells, whereas the AbiQ^- cells contained processed (mature) phage DNA in addition to the concatenated form. The production of the major capsid protein of phage c21 was not hindered in the cells harboring AbiQ. [TOP OF PAGE]

74. rexB of bacteriophage lambda is an anti-cell death gene. Engelberg-Kulka, H., Reches, M., Narasimhan, S., Schoulaker-Shwarz, R., Klemes, Y., Aizenman, E., Glaser, G. (1998). Proc. Natl. Acad. Sci. USA 95:15481-15486. In Escherichia coli, programmed cell death is mediated through "addiction modules" consisting of two genes; the product of one gene is long-lived and toxic, whereas the product of the other is short-lived and antagonizes the toxic effect. Here we show that the product of lambdarexB, one of the few genes expressed in the lysogenic state of bacteriophage lambda, prevents cell death directed by each of two addiction modules, phd-doc of plasmid prophage P1 and the rel mazEF of E. coli, which is induced by the signal molecule guanosine 3',5'-bispyrophosphate (ppGpp) and thus by amino acid starvation. lambdaRexB inhibits the degradation of the antitoxic labile components Phd and MazE of these systems, which are substrates of ClpP proteases. We present a model for this anti-cell death effect of lambdaRexB through its action on the ClpP proteolytic subunit. We also propose that the lambdarex operon has an additional function to the well known phenomenon of exclusion of other phages; it can prevent the death of lysogenized cells under conditions of nutrient starvation. Thus, the rex operon may be considered as the "survival operon" of phage lambda. [TOP OF PAGE]

75. Epidemiology, genetics, and ecology of toxigenic Vibrio cholerae. Faruque, S.M., Albert, M.J., Mekalanos, J.J. (1998). Microbiology and Molecular Biology Reviews 62:1301-314. Cholera caused by toxigenic Vibrio cholerae is a major public health problem confronting developing countries, where outbreaks occur in a regular seasonal pattern and are particularly associated with poverty and poor sanitation. The disease is characterized by a devastating watery diarrhea which leads to rapid dehydration, and death occurs in 50 to 70% of untreated patients. Cholera is a waterborne disease, and the importance of water ecology is suggested by the close association of V. cholerae with surface water and the population interacting with the water. Cholera toxin (CT), which is responsible for the profuse diarrhea, is encoded by a lysogenic bacteriophage designated CTXPhi. Although the mechanism by which CT causes diarrhea is known, it is not clear why V. cholerae should infect and elaborate the lethal toxin in the host. Molecular epidemiological surveillance has revealed clonal diversity among toxigenic V. cholerae strains and a continual emergence of new epidemic clones. In view of lysogenic conversion by CTXPhi as a possible mechanism of origination of new toxigenic clones of V. cholerae, it appears that the continual emergence of new toxigenic strains and their selective enrichment during cholera outbreaks constitute an essential component of the natural ecosystem for the evolution of epidemic V. cholerae strains and genetic elements that mediate the transfer of virulence genes. The ecosystem comprising V. cholerae, CTXPhi, the aquatic environment, and the mammalian host offers an understanding of the complex relationship between pathogenesis and the natural selection of a pathogen. [TOP OF PAGE]

76. Induction of the lysogenic phage encoding Cholera toxin in naturally occurring strains of toxigenic Vibrio cholerae O1 and O139. Faruque, S.M., Asadulghani, Abdul, A., Albert, M.J., Nasirul, I., Mekalanos, J.J. (1998). Infect. Immun. 66:3752-3757. [TOP OF PAGE]

77. Assessment of the effects of various UV sources on inactivation and photoproduct induction in phage T7 dosimeter. Fekete, A., Vink, A.A., Gaspar, S., Berces, A., Modos, K., Ronto, G., Roza, L. (1998). PHOTOCHEMISTRY AND PHOTOBIOLOGY 68:527-531. The correlation between the biologically effective dose (BED) of a phage T7 biological dosimeter and the induction of cyclobutane pyrimidine dimers (CPD) and (6-4) photoproducts ((6-4)PD) in the phage DNA was determined using seven various UV sources. The BED is the inactivation rate of phage T7 expressed in HT7 units. The CPD and (6-4)PD were determined by lesion-specific monoclonal antibodies in an immunodot-blot assay. The various lamps induced these lesions at different rates; the relative induction ratios of CPD to (6-4)PD increased with increasing effective wavelength of irradiation source. The amount of total adducts per phage was compared to the BED of phage T7 dosimeter, representing the average number of UV lesions in phage. For UVC (200-280 nm radiation) and unfiltered TL01 the number of total adducts approximates the reading; however, UV sources having longer effective wavelengths produced fewer CPD and (6-4)PD. A possible explanation is that although the most relevant lesions by UVC are the CPD and (6-4)PD, at longer wavelengths other photoproducts can contribute to the lethal damage of phages. The results emphasize the need to study the biological effects of solar radiation because the lesions responsible for the lethal effect may be different from those produced by various UV sources. [TOP OF PAGE]

78. A short noncoding viral DNA element showing characteristics of a replication origin confers bacteriophage resistance to Streptococcus thermophilus. Foley, S., Lucchini, S., Zwahlen, M.C., Brussow, H. (1998). Virology 250:377-387. A 302-bp noncoding DNA fragment from the DNA replication module of phage fSfi21 was shown to protect the Streptococcus thermophilus strain Sfi1 from infection by 17 of 25 phages. The phage-inhibitory DNA possesses two determinants, each of which individually mediated phage resistance. The phage-inhibitory activity was copy number dependent and operates by blocking the accumulation of phage DNA. Furthermore, when cloned on a plasmid, the fSfi21 DNA acts as an origin of replication driven by phage infection. Protein or proteins in the fSfi21-infected cells were shown to interact with this phage-inhibitory DNA fragment, forming a retarded protein-DNA complex in gel retardation assays. A model in which phage proteins interact with the inhibitory DNA such that they are no longer available for phage propagation can be used to explain the observed bacteriophage resistance. Genome analysis of fSfi19, a phage that is insensitive to the inhibitory activity of the fSfi21fSfi21-derived DNA, led to the characterisation of a variant putative phage replication origin that differed in 14 of 302 nucleotides from that of fSfi21. The variant origin was cloned and exhibited an inhibitory activity toward phages that were insensitive to the fSfi21-derived DNA. Copyright 1998 Academic Press. [TOP OF PAGE]

79. Genome structure of mycobacteriophage D29: implications for phage evolution. Ford, M.E., Sarkis, G.J., Belanger, A.E., Hendrix, R.W., Hatfull, G.F. (1998). J. Mol. Biol. 279:143-164. Mycobacteriophage D29 is a lytic phage that infects both fast and slow-growing mycobacterial species. The complete genome sequence of D29 reveals that it is a close relative of the temperate mycobacteriophage L5, whose sequence has been described previously. The overall organization of the D29 genome is similar to that of L5, although a 3.6 kb deletion removing the repressor gene accounts for the inability of D29 to form lysogens. Comparison of the two genomes shows that they are punctuated by a large number of insertions, deletions, and substitutions of genes, consistent with the genetic mosaicism of lambdoid phages. [TOP OF PAGE]

80. Characterization of Lactobacillus fermentum bacteriophage Z63-B2. Foschino, R., Castiglioni, E., Galli, A. (1998). Annali di Microbiologia ed Enzimologia 48:151-159. This communication reports physiologic and structural characteristics of phage Z63-B2 active on Lactobacillus fermentum strain ATCC 9338; a comparison with phage Z63-B1, previously isolated from the same kind of environment (sourdoughs for bread-making) was discussed. Z63-B2 showed a multiplicative cycle with a burst size of 100 PFU per infectious centre and a latent period of 150 min. Its electrophoretical profile of proteins differed from that of phage Z63-B1 only for one minor protein. DNA fragments obtained with different restriction enzymes resulted very similar and a high homology between the viruses was confirmed by hybridization tests. Two phages prove to be variants each other. Resistant clones to phage Z63-B2 isolated after lysis of the host strain, showed costantly a different cell morphology and colony growth in comparison with the original host strain; however resistance was not imputable to a lysogenic state. [TOP OF PAGE]

81. Occurrence of a sequence in marine cyanophages similar to that of T4 gp20 and its application to PCR-based detection and quantification techniques. Fuller, N.J., Wilson, W.H., Joint, I.R., Mann, N.H. (1998). Appl. Environ. Microbiol. 64:2051-2060. Viruses are ubiquitous components of marine ecosystems and are known to infect unicellular phycoerythrin-containing cyanobacteria belonging to the genus Synechococcus. A conserved region from cyanophage genome was identified in three genetically distinct cyanomyoviruses, and a sequence analysis revealed that this region exhibited significant similarity to a gene encoding a capsid assembly protein (gp20) from the enteric coliphage T4. The results of a comparison of gene 20 sequences from three cyanomyoviruses and T4 allowed us to design two degenerate PCR primers, CPS1 and CPS2, which specifically amplified a 165-bp region from the majority of cyanomyoviruses tested. A competitive PCR (cPCR) analysis revealed that cyanomyovirus strains should be accurately enumerated, and it was demonstrated that quantification was log-linear over ca. 3 orders of magnitude. Different calibration curves were obtained for each of the three cyanomyovirus strains tested; consequently, cPCR performed with primers CPS1 and CPS2 could lead to substantial inaccuracies in estimates of phage abundance in natural assemblages. Further sequence analysis of cyanomyovirus gene 20 homologs would be necessary in order to design primers which do not exhibit phage-to-phage variability in priming efficiency. It was demonstrated that PCR products of the correct size could be amplified from seawater samples following 100x concentration and even directly without any prior concentration. Hence, the use of degenerate primers in PCR analysis of cyanophage populations should provide valuable data on the diversity of cyanophages in natural assemblages. Further optimization of procedures may ultimately lead to a sensitive assay which can be used to analyze natural cyanophage populations both quantitatively (by cPCR) and qualitatively following phylogenetic analysis of amplified products. [TOP OF PAGE]

82. [Comparative study of Morganella and Providencia bacteriophages]. Gabrilovich, I.M., Zarochentsev, M.V., Saimov, S.R. (1998). Zhurnal Mikrobiologii, Epidemiologii i Immunobiologii ???:20-22. 7 strains of M.morganii phages and 7 strains of P.rettgeri phages were isolated from lysogenic cultures and the environment. The main biological properties of these phages were studied. The phages under study formed independent taxonomic groups. These phages were found to be highly specific and capable of being used for the identification of bacteria. [TOP OF PAGE]

83. Sravnitel'noe izuchenie bakteriofagov Morganella i Providencia [Comparative study of Morganella and Providencia bacteriophages]. Gabrilovich, I.M., Zarochensev, M.V., Saimov, S.R. (1998). Zhurnal Mikrobiologii, Epidemiologii i Immunobiologii 5:20-22. 7 strains of M.morganii phages and 7 strains of P.rettgeri phages were isolated from lysogenic cultures and the environment. The main biological properties of these phages were studied. The phages under study formed independent taxonomic groups. These phages were found to be highly specific and capable of being used for the identification of bacteria. [TOP OF PAGE]

84. Phage restriction and the presence of small plasmids in Salmonella enteritidis. Gado, I., Laszlo, V.G., Nagy, B., Milch, H., Drin, I., Awad-Masalmeh, M., Horvath, J. (1998). Zentralblatt Fur Bakteriologie 287:509-519. Between 1990-1994, a total of 16,505 S. enteritidis strains of human, animal and food origin were phage-typed, using the Hungarian scheme and the changes of incidence of the dominant phage types were monitored. The incidence of PT1 (corresponding to Ward's PT1 was very high between 1990 and 1992 (67.9-71.0% of the total S. enteritidis isolates), later, it decreased. The prevalence of PT6 (corresponding to Ward's PT4) was rare until 1992, then it gradually increased. The phage type and plasmid content of 78 Salmonella enteritidis strains were determined. Small plasmids were present in 59% of the isolates, together with a serotype-specific (38 MDa) plasmid. A correlation was found between the presence of the small plasmid and phage restriction to two phages used for subdividing the Hungarian phage types 1 (PT1) and 6 (PT6) of S. enteritidis (corresponding to PT1 and PT4 in Ward's typing scheme, respectively). [TOP OF PAGE]

85. Detection of infectious enteroviruses, enterovirus genomes, somatic coliphages, and Bacteroides fragilis phages in treated wastewater. Gantzer, C., Maul, A., Audic, J.M., Schwartzbrod, L. (1998). Appl. Environ. Microbiol. 64:4307-4312. In this study, three types of treated wastewater were tested for infectious enteroviruses, the enterovirus genome, somatic coliphages, and Bacteroides fragilis phages. The aim of this work was to determine whether the presence of the two types of bacteriophages or of the enterovirus genome was a good indicator of infectious enterovirus contamination. The enterovirus genome was detected by reverse transcription-polymerase chain reaction. Infectious enteroviruses were quantified by cell culturing (BGM cells), and the bacteriophages were quantified by plaque formation on the host bacterium (Escherichia coli or B. fragilis) in agar medium. Forty-eight samples of treated wastewater were analyzed. Sixteen samples had been subjected to a secondary treatment for 8 to 12 h (A), 16 had been subjected to a secondary treatment for 30 h (B1), and 16 had been subjected to both secondary and tertiary treatments (B2). The mean concentrations of somatic coliphages were 4.9 x 10(4) PFU . liter-1 for treatment line A, 9.8 x 10(3) PFU . liter-1 for B1, and 1.4 x 10(3) PFU . liter-1 for B2, with all the samples testing positive (100%). The mean concentrations of B. fragilis phages were 1.7 x 10(3) PFU . liter-1 for A (100% positive samples), 17 to 24 PFU . liter-1 for B1 (44% positive samples), and 0.8 to 13 PFU . liter-1 for B2 (6% positive samples). The mean concentrations of infectious enteroviruses were 4 most probable number of cytopathogenic units (MPNCU) . liter-1 for A (31% positive samples) and <1 MPNCU . liter-1 for B1 and B2 (0% positive samples). The percentages of samples testing positive for the enterovirus genome were 100% for A, 56% for B1, and 19% for B2. The percentages of samples testing positive for the enterovirus genome were significantly higher than those for infectious enteroviruses. This finding may have been due to the presence of noninfectious enteroviruses or to the presence of infectious enteroviruses that do not multiply in BGM cell cultures. However, under our experimental conditions, nondetection of the genome implies the absence of infectious viruses. There was a significant correlation between the concentration of somatic coliphages or B. fragilis phages and the presence of infectious enteroviruses or the presence of the enterovirus genome. However, the somatic coliphage concentration did not lead to fluctuations in the infectious enterovirus concentration, whereas the B. fragilis phage concentration did. [TOP OF PAGE]

86. Characterization of a lytic virus infectious to the bloom-forming microalga Aureococcus anophagefferens (Pelagophyceae). Garry, R.T., Hearing, P., Cosper, E.M. (1998). Journal of Phycology 34:616-621. Aureococcus anophagefferens Hargraves and Sieburth has caused recurring monospecific blooms in Long Island embayments since it was first described in 1985. It was termed the "brown tide," due to the resulting water color, and has had a devastating effect on Long Island's (New York) marine ecosystem. In 1992, a virus that was capable of causing lysis of A. anophagefferens was isolated and maintained in culture. We report on the further characterization of this virus, Aureococcus anophagefferens virus-1 (AaV-1), indicated by a buoyant density of 1.2776 g times mL super(-1) in a CsCl equilibrium gradient. Electron microscopy revealed a phage with a hexagonal head and tail similar to previously described phages. By using adenovirus for calibration, the virus was found to have a head 50-55 nm wide and a tail 70-75 nm long. The viral band was infectious to A. anophagefferens after dialysis. The virus was composed of at least 16 distinct polypeptides ranging in molecular weight from 20 to 230 kDa. The adsorption coefficient for the virus was 7.2 x 10 super(-9) mL times min super(-1), and the burst size was calculated to be 9.4 viruses per A. anophagefferens cell at 20 degree C. Complete lysis of A. anophagefferens occurred with a titer as low as 893 viruses times mL super(-1), and the lower limit of infectivity was 93 viruses times mL super(-1). The virus lost its infectivity between 30 degree and 40 degree C. These results suggest that AaV-1 is highly infectious and that the role of the virus in preventing or ending A. anophagefferens blooms needs further investigation. [TOP OF PAGE]

87. A species barrier between bacteriophages T2 and T4: exclusion, join-copy and join-cut-copy recombination and mutagenesis in the dCTPase genes. Gary, T.P., Colowick, N.E., Mosig, G. (1998). Genetics 148:1461-1473. Bacteriophage T2 alleles are excluded in crosses between T2 and T4 because of genetic isolation between these two virus species. The severity of exclusion varies in different genes, with gene 56, encoding an essential dCT(D)Pase/dUT(D)Pase of these phages, being most strongly affected. To investigate reasons for such strong exclusion, we have (1) sequenced the T2 gene 56 and an adjacent region, (2) compared the sequence with the corresponding T4 DNA, (3) constructed chimeric phages in which T2 and T4 sequences of this region are recombined, and (4) tested complementation, recombination, and exclusion with gene 56 cloned in a plasmid and in the chimeric phages in Escherichia coli CR63, in which growth of wild-type T2 is not restricted by T4. Our results argue against a role of the dCTPase protein in this exclusion and implicate instead DNA sequence differences as major contributors to the apparent species barrier. This sequence divergence exhibits a remarkable pattern: a major heterologous sequence counter-clockwise from gene 56 (and downstream of the gene 56 transcripts) replaces in T2 DNA the T4 gene 69. Gene 56 base sequences bordering this substituted region are significantly different, whereas sequences of the dam genes, adjacent in the clockwise direction, are similar in T2 and in T4. The gene 56 sequence differences can best be explained by multiple compensating frameshifts and base substitutions, which result in T2 and T4 dCTPases whose amino acid sequences and functions remain similar. Based on these findings we propose a model for the evolution of multiple sequence differences concomitant with the substitution of an adjacent gene by foreign DNA: invasion by the single-stranded segments of foreign DNA, nucleated from a short DNA sequence that was complementary by chance, has triggered recombination-dependent replication by "join-copy" and "join-cut-copy" pathways that are known to operate in the T-even phages and are implicated in other organisms as well. This invasion, accompanied by heteroduplex formation between partially similar sequences, and perhaps subsequent partial heteroduplex repair, simultaneously substituted T4 gene 69 for foreign sequences and scrambled the sequence of the dCTPase gene 56. We suggest that similar mechanisms can mobilize DNA segments for horizontal transfer without necessarily requiring transposase or site-specific recombination functions. [TOP OF PAGE]

88. The effect of cyanophages on the morality of Synechococcus spp. and selection for UV resistant viral communities. Garza, D.R., Suttle, C.A. (1998). Microb. Ecol. 36:281-??? [TOP OF PAGE]

89. Ultrastructural analysis of viral invection in the brown-tide alga, Aureococcus anophagefferens (Pelagophyceae). Gastrich, M.D., Anderson, O.R., Benmayor, S.S., Cosper, E.M. (1998). Phycologia 37:300-306. The DNA-containing virus (BtV) is known to lyse laboratory cultures of Aureococcus anophagefferens Hargraves et Sieburth, an alga known to cause blooms devastating to shellfish and eelgrass beds. Ultrastructural study of the infection of A. anophagefferens by this virus shows a progressive degradation of host algal cells. Healthy uninfected algal cells (c. 2.0 mu m) exhibit organelles typical of the Pelagophyceae and are surrounded by a prominent fibrous glycocalyx. All laboratory cultures of A. anophagefferens inoculated with the BtV virus were lysed within 24-48 h, leaving no living cells. Infected brown-ride cells had an unusually electron-dense, crenated plasma membrane and lacked a glycocalyx. During early stages of infection, the vacuole disappeared, and the nucleus was disrupted by the formation of viroplasm. The organelles disappeared, with the chloroplast being the last to degrade. A few intracellular viral capsids (c. 140-160 nm) were observed during the degeneration of the organelles. In the final stages of infection, the entire host cell was filled with viroplasm and viral capsids, and no organelles remained. [TOP OF PAGE]

90. High titer, phage-neutralizing antibodies in bovine colostrum that prevent lytic infection of Lactococcus lactis in fermentations of phage-contaminated milk. Geller, B.L., Kraus, J., Schell, M.D., Hornsby, M.J., Neal, J.J., Ruch, F.E. (1998). Journal of Dairy Science 81:895-900. Antibodies against six phages of Lactococcus lactis were produced in six bovine colostra. Each colostrum neutralized its homologous phage. In addition, each colostrum neutralized a different phage. from the same species as its homologous phage, but either did not neutralize or weakly neutralized more distantly related lactococcal phages. The neutralization of heterologous phages correlated with the phage species but not with the strain on which the phage was grown. Blood serum from the same cows also neutralized homologous phages, but the titers were lower than that of the colostrum. Addition of colostrum to phage-contaminated milk prevented lysis of starter cultures of L. lactis. The titers of some of the colostra were sufficiently high that it may be economically practical to prepare antibodies from similar, high titer colostra for commercial use in factory bulk starter vats. [TOP OF PAGE]

91. Membrane receptor for prolate phages is not required for infection of Lactococcus lactis by small or large isometric phages. Geller, B.L. (1998). Journal of Dairy Science 81:2329-2335. Lactococcus lactis contains a chromosomal gene (pip) for a membrane protein that serves as a receptor for the prolate bacteriophage c2 and other phages of the c2 species. A mutated allele of this receptor gene was used to replace the wild-type allele in L. lactis strains MM210, NCK 203, and C2. Allele replacement was confirmed by the presence of a restriction site marker in a polymerase chain reaction product from the mutated allele. The mutated pip derivative of strain C2 was completely resistant to phages of the c2 species but was fully sensitive to the small isometric phage sk1 of the 936 species, as expected. The mutated derivatives of MM210 and NCK203 were fully sensitive to the small isometric phages mm210b and 31 (p335 species) and to the large isometric phage 949 (949 species). These results show that pip is not required for infection by phages of species 936, p335, or 949. The resultant mutants grew as well as the parental strains in liquid media. The mutated derivatives of MM210 and C2 acidified and clotted milk as readily as the wild-type strains. These results show that phage receptor replacement in a commercial strain of L. lactis does not affect growth and acid production in milk. [TOP OF PAGE]

92. Origin, adaptation and evolutionary pathways of fungal viruses. Ghabrial, S.A. (1998). Virus Genes 16:119-131. Fungal viruses or mycoviruses are widespread in fungi and are believed to be of ancient origin. They have evolved in concert with their hosts and are usually associated with symptomless infections. Mycoviruses are transmitted intracellularly during cell division, sporogenesis and cell fusion, and they lack an extracellular phase to their life cycles. Their natural host ranges are limited to individuals within the same or closely related vegetative compatibility groups. Typically, fungal viruses are isometric particles 25-50 nm in diameter, and possess dsRNA genomes. The best characterized of these belong to the family Totiviridae whose members have simple undivided dsRNA genomes comprised of a coat protein (CP) gene and an RNA dependent RNA polymerase (RDRP) gene. A recently characterized totivirus infecting a filamentous fungus was found to be more closely related to protozoan totiviruses than to yeast totiviruses suggesting these viruses existed prior to the divergence of fungi and protozoa. Although the dsRNA viruses at large are polyphyletic, based on RDRP sequence comparisons, the totiviruses are monophyletic. The theory of a cellular self-replicating mRNA as the origin of totiviruses is attractive because of their apparent ancient origin, the close relationships among their RDRPs, genome simplicity and the ability to use host proteins efficiently. Mycoviruses with bipartite genomes (partitiviruses), like the totiviruses, have simple genomes, but the CP and RDRP genes are on separate dsRNA segments. Because of RDRP sequence similarity, the partitiviruses are probably derived from a totivirus ancestor. The mycoviruses with unencapsidated dsRNA-like genomes (hypoviruses) and those with bacilliform (+) strand RNA genomes (barnaviruses) have more complex genomes and appear to have common ancestry with plant (+) strand RNA viruses in supergroup 1 with potyvirus and sobemovirus lineages, respectively. The La France isometric virus (LIV), an unclassified virus with multipartite dsRNA genome, is associated with a severe die-back disease of the cultivated mushroom. LIV appears to be of recent origin since it differs from its host in codon usage. [TOP OF PAGE]

93. Metastabil'nost' fenotipa u bakterii [Metastable phenotype of bacteria]. Golovlev, E.L. (1998). Mikrobiologica 67:149-155. This review analyzes data available in the literature and the author's own data on the phenotypic variability of bacteria that occurs within the framework of a genotype unchanging in terms of the genetic information stored. This variability is a form of bacterial adaptation to an unstable environment and results from a specific form of natural selection. This phenomenon arose evolutionarily not as a mechanism to provide genetic diversity for the divergence process but as a mechanism of species stabilization; therefore, it was termed phenotype metastability. It includes, as specific variants, processes known as phase and antigenic variations, R-S-M dissociation, phenotype conversion, etc. The mechanisms of phenotype metastability are extremely diverse. They include alternative expression (of the switch on-switch off type) of individual genes or small groups of genes; variation in the composition of synthesized proteins controlled at the level of transcription; expression of complex phenotypes adapted to different environmental conditions that involves phage transposition, reading-frame-shift mutations, etc. The phenomenon of phenotype metastability is widespread among bacteria. [TOP OF PAGE]

94. Protecting the neighborhood: Extreme measures. Gottesman, S. (1998). Proc. Natl. Acad. Sci. USA 95:2731-2732. In the unending wars of organism vs. organism, the growth of bacteriophage and the defenses raised by bacteria were among the first recognized and continue to provide new variations and insights on ways to defend oneself. A paper in this issue of the Proceedings demonstrates that prokaryotes, like eukaryotes, have chosen proteolytic self-destruction as a route to protection from attack, albeit a protection for the community rather than for the cell under attack (1). [TOP OF PAGE]

95. Predicting disinfection performance in continuous flow systems from batch disinfection kinetics. Haas, C.N., Joffe, J., Heath, M., Jacangelo, J., Anmangandla, U. (1998). Water Science and Technology 38:171-179. Disinfection processes have often been characterized by the "CT" concept i.e., the product of disinfectant residual and contact time (perhaps as a function of pH, temperature, and other water quality variations) produces a given level of disinfection. The objective of this work was to develop and validate the use of reaction kinetic models for disinfection process design. Using bench scale (batch) kinetic information, and hydraulic characterization of pilot scale continuous disinfection processes, predictions of continuous process performance were made using a segregated flow model. These predictions were compared to independent experimental measurements of actual inactivation in pilot scale processes. Preammoniation, free residual chlorination, and ozonation were used on two waters from Portland, Oregon (US). Organisms used were Giardia muris, bacteriophage MS2, and Escherichia coli. [TOP OF PAGE]

96. Legionella pneumophila kills human phagocytes but not protozoan host cells by inducing apoptotic cell death. Hagele, S., Hacker, J., Brand, B.C. (1998). FEMS Microbiol. Let. 169:51-58. Legionella pneumophila is a facultative intracellular parasite able to replicate within and to kill a variety of eukaryotic cells. One possible killing mechanism is the induction of programmed cell death. Based on electron microscopy and flow cytometry studies using the phosphatidylserine binding protein annexin V, we could demonstrate that L. pneumophila is able to induce apoptosis in human monocytes which was clearly dependent on the multiplicity of infection, the time postinfection and the intracellular location of the bacteria. Furthermore, it became evident that Legionella-induced apoptosis does not require the TNF-alpha mediated signal-transduction pathway. By studying infection in Acanthamoeba castellanii, we found that L. pneumophila is not able to induce programmed cell death in their natural host cells indicating that different mechanisms are responsible for host cell killing in protozoan and human cells. [TOP OF PAGE]

97. Evaluation of alginate-encapsulated Azotobacter chroococcum as a phage-resistant and an effective inoculum. Hammad, A.M.M. (1998). Journal of Basic Microbiology 38:9-16. The efficiency of free and alginate-encapsulated Azotobacter chroococcum in fixing nitrogen and their susceptibility to bacteriophages were studied in pure liquid cultures (in vitro) and under cultivated soil conditions (in vivo). Bacteriophages of A. chroococcum were isolated and were found to be common in soil of the Experimental Farm of Fac. Agric., Minia Univ., Egypt. In pure liquid cultures, the immobilized cells exhibited much higher nitrogenase activity (about 57 fold) than the free ones. The encapsulation system offered high protection to A. chroococcum against their phages. No nitrogenase activity was detected for the free cells in presence of phages. Under cultivated soil conditions, inoculation of maize plants (Zea mays, cv. GIZA 2) with immobilized A. chroococcum, markedly increased rhizosphere and rhizoplane Azotobacter population, significantly increased plant N% as well as dry weight/plant, compared to those inoculated with free cells. In free cells inoculated-plants, bacteriophages had a marked depressive effect on rhizosphere and rhizoplane Azotobacter population, significantly reduced plant N% and dry weight/plant, as compared to plants inoculated with free cells in absence of phages. In plants inoculated with immobilized cells, no significant effect for presence of phages was detected in plant N% and dry weight/plant, whereas, a slight reduction in rhizosphere and rhizoplane Azotobacter population was observed. [TOP OF PAGE]

98. Efficacy and mechanisms of action of sodium hypochlorite on Pseudomonas aeruginosa PAO1 phage F116. Hann, A.C., Baubet, V., Perrin, R. (1998). Journal of Applied Microbiology 85:925-932. The Pseudomonas aeruginosa PAO1 phage F116 was used to investigate the viricidal activity and the mechanism of action of sodium hypochlorite. The bacteriophage was inactivated with a low concentration (0.0005% available chlorine) of the biocide prepared in tap water but it was less sensitive to a sodium hypochlorite solution prepared in ultra-pure water (0.0075% available chlorine). For all the effective concentrations of sodium hypochlorite (i.e. producing at least 4 log reduction in phage titre), F116 was readily inactivated within 30 s. Electron microscopical investigations of the phage particles challenged with sodium hypochlorite showed a wide variety of deleterious effects, some of which have not been previously observed with other biocides. The wide range of structural alterations observed suggested that sodium hypochlorite has multiple target sites against F116 bacteriophage. A 30 s exposure to sodium hypochlorite (0.001% available chlorine) produced severe damage, the number and severity of which increased with a higher concentration (0.0075% available chlorine) and with a longer contact time. These observations suggested that sodium hypochlorite inactivated F116 bacteriophage by causing structural alterations to the phage head, tail and overall structure, hence possibly releasing the viral genome from damaged capsids in the surrounding media. [TOP OF PAGE]

99. Biological control of bacterial blight of geranium with h-mutant bacteriophages. Harbaugh, B.K., Jones, J.B., Jackson, L.E., Somodi, G., Flaherty, J.E. (1998). Hortscience 33:519 [TOP OF PAGE]

100. ??? Hausmann, R., Härle, E. (1998). Proc. Eur. Biophys. Congr. 1:467-??? [TOP OF PAGE]

101. Optimising starter culture performance in NZ cheese plantsproduction. Heap, H.A. (1998). Australian Journal of Dairy Technology 53:74-78. [TOP OF PAGE]

102. Virus-mediated total release of dimethylsulfonioproprionate from marine phytoplankton: a potential climate process. Hill, R.W., White, B.A., Cottrell, M.T., Dacey, J.W.H. (1998). Aquat. Microb. Ecol. 14:1-6. [TOP OF PAGE]

103. Microbial indicator reductions in alternative treatment systems for swine wastewater. Hill, V.R., Sobsey, M.D. (1998). Water Science and Technology 38:119-122. Bacterial, viral and parasitic pathogens in swine wastes are of public health concern because many are able to infect humans. Hence, treatment processes must be effective in removing or destroying these microbes before wastewater discharge. Primary treatment by anaerobic lagoon is the current best management practice (BMP) for swine wastewater in the USA but alternative processes were also investigated for their potential to improve treatment. Wastewater samples were collected approximately monthly from March-December 1997 at a North Carolina swine nursery. Geometric mean concentrations for bacterial indicators (faecal coliforms, E. coli, enterococci and C. perfringens spores) in lagoon effluent were 3.3X10⁵, 2.8X10⁵, 3.4X10⁵ and 2.2X10⁴ CFU/100mL respectively. For somatic and male-specific coliphages they were 1.4X10⁵ and 5.0X10³ PFU/100mL respectively. Bacterial indicator levels in swine lagoon effluents are much higher than allowed for municipal wastewater effluents discharged to land or water. The anaerobic lagoon achieved reductions of 1.1-2.2 log10 for all indicators except C. perfringens spores (0.2 log10). Of the secondary treatment processes, constructed wetlands achieved the best indicator microbe reductions ranging from 1.1-2.5 log10. A media filter and an overland flow system achieved mean indicator reductions of only 0.2-1.2 and 0.2-0.8 log10, respectively. The results indicate that a primary-secondary treatment system, an anaerobic lagoon and constructed wetlands, can achieve reductions of 2.9-4.8 log10 for bacterial and viral indicators and 1.5 log10 for C. perfringens spores. [TOP OF PAGE]

104. Reassessment of medicinal phage……. Holzman, D. (1998). ASM News 64:620-622. [TOP OF PAGE]

105. Phage as antibacterial tool. Holzman, D. (1998). Genetic Engineering News 18(18), 1-48. [TOP OF PAGE]

106. …Spurs companies to study therapeutic uses. Holzman, D. (1998). ASM News 64:622-623. [TOP OF PAGE]

107. Evolutionary relationships among putative RNA-dependent RNA polymerases encoded by a mitochondrial virus-like RNA in the Dutch elm disease fungus, Ophiostoma novo-ulmi, by other viruses and virus-like RNAs and by the Arabidopsis mitochondrial genome. Hong, Y., Cole, T.E., Brasier, C.M., Buck, K.W. (1998). Virology 246:158-169. The nucleotide sequence (2617 nucleotides) of virus-like double-stranded (ds) RNA 3a in a diseased isolate, Log1/3-8d2 (Ld), of the ascomycete fungus Ophiostoma novo-ulmi has been determined. One strand of the dsRNA contains an open reading frame (ORF) with the potential to encode a protein of 718 amino acids, and the complementary strand contains two smaller ORFs with the potential to encode proteins of 178 and 182 amino acids, respectively. The large ORF contains 12 UGA codons which code for tryptophan in ascomycete mitochondria and has a codon bias typical of mitochondrial genes, consistent with the localization of Ld dsRNAs within the mitochondria. The amino acid sequence contains motifs characteristic of RNA-dependent RNA polymerases (RdRps). This putative RdRp was shown to be related to putative RdRps of mitochondrial dsRNAs of another ascomycete and a basidiomycete fungus and also to a putative RdRp encoded by the mitochondrial genome of Arabidopsis thaliana. In multiple sequence alignments, the fungal mitochondrial dsRNA-encoded RdRp-like proteins formed a cluster, ancestrally related to the RdRps of the yeast 20S and 23S RNA replicons and of the positive-stranded RNA bacteriophages of the Leviviridae family, but distinct from RdRps of other families and genera of fungal RNA viruses and related plant and animal RNA viruses. Northern blot analysis with RNA 3a strand-specific probes indicated that nucleic acid extracts of Ld contain more single-stranded (positive-stranded) RNA than dsRNA, consistent with an evolutionary relationship between RNA 3a and positive-stranded RNA phages. [TOP OF PAGE]

108. A comparison of two methods to recover phages from soil samples. Hu, T.L. (1998). Bioresource Technology 65:167-169. Environmental contamination caused by viruses has received extensive interest. The adsorption of viruses in soil can influence the extent of groundwater pollution. Many methods have been applied to detecting viruses in soil samples. Different elution methods lead to differences of viral titers. In this study, two elution methods were compared: glycine buffer and beef extract of phages from a soil sample. Experimental results indicated that, for both methods, the phage recovery increased with an increasing contact time between phages and soil sample. The phage recovery for the glycine buffer method increased only slightly when the elution time was increased from 2 to 10 min. However, the phage recovery for the beef extract method was higher when the elution time was increased to 6 min. At an elution time of 2 min., the glycine buffer method yielded a higher phage recovery than the beef extract method. Although both elution methods closely resembled each other in terms of the phage titers of an environmental sample, the glycine buffer method was simpler, faster, and would be more appropriate for detecting and enumerating phage when many soil or sediment samples are employed. [TOP OF PAGE]

109. Biofilm susceptibility to bacteriophage attack: The role of phage-borne polysaccharide depolymerase. Hughes, K.A., Sutherland, I.W., Jones, M.V. (1998). Microbiology (Reading) 144:3039-3047. Biofilm bacteria Enterobacter agglomerans 53b and Serratia marcescens Serr were isolated from a food processing factory. A bacteriophage (SF153b), which could infect and lyse strain 53b, was isolated from sewage. This has been shown to possess a polysaccharide depolymerase enzyme specific for the exopolysaccharide (EPS) of strain 53b. Using batch culture and chemostat-linked Modified Robbins Device systems it was observed that SF153b could degrade the EPS of a mono-species biofilm (strain 53b) and infect the cells. The disruption of the biofilm by phage was a combination of EPS degradation by the depolymerase and infection and subsequent cell lysis by the phage. Strain Serr biofilms were not susceptible to the phage and the biofilm EPS was not degraded by the phage glycanase, with the result that the biofilm was unaffected by the addition of SF153b phage. Scanning electron microscopy confirmed that specific phage could extensively degrade susceptible biofilms and continue to infect biofilm bacteria whilst EPS degradation was occurring. [TOP OF PAGE]

110. Bacteriophage and associated polysaccharide depolymerases--novel tools for study of bacterial biofilms [published erratum appears in J Appl Microbiol 1999 Feb;86(2):359]. Hughes, K.A., Sutherland, I.W., Clark, J., Jones, M.V. (1998). Journal of Applied Microbiology 85:583-590. Bacteriophage for three representative strains of Gram-negative biofilm bacteria have proved to be of widespread occurrence. Lytic bacteriophage have been isolated from local sewage for the bacterium 1.15, an exopolysaccharide (EPS)-producing pseudomonad found originally as a component of biofilms in a local river, and for two Enterobacter agglomerans strains from industrial biofilms. Representative examples of all three bacteriophage possess a relatively low burst size and on solid media, exhibit very large plaques surrounded by a wide halo (5-20 mm) indicative of polysaccharide depolymerase action. The bacteriophage are thus similar to other viruses for EPS-producing bacteria in inducing the synthesis of enzymes degrading the polymers which occlude the bacterial cell surface. In each preparation, the polysaccharase activity was associated both with sedimented phage particles and with the supernate of bacterial lysates. The enzymes have been partially purified and used to prepare polysaccharide digests in which the major products from each polysaccharide are the presumed repeat units of the polymers or oligomers of these. The soluble phage enzymes each degrade their substrate by acting as endo-glycanohydrolases. The phage and their associated enzymes thus provide very useful highly specific tools for studies of biofilms incorporating the bacterial host strains. Their potential applications in studies on bacterial biofilms are discussed. [TOP OF PAGE]

111. Lysis of bacteriophages, Lactococcus spp., flow cytometric analysis. Hutter, K.J., Guo, X., Schueller, G., Suessmuth, R. (1998). Advances in Food Sciences 20:7-12. Dairy products are not fermented by the natural microorganisms of milk but by inoculated starting cultures of Lactococcus spp. 70 to 80% of fermentation problems are caused by the induction of bacteriophages. Flow cytometry was used as a practicable method to control the growth and proliferation of bacteria by means of online DNA analysis at different points of time. Most of the Lactococcus cells are dying at the moment of lysis of bacteriophages. Therefore, only the resistant cells are detectable by flow cytometric analysis. [TOP OF PAGE]

112. A novel filamentous phage, fs-2, of Vibrio cholerae O139. Ikema, M., Honma, Y. (1998). Microbiology 144 ( Pt 7):1901-1906. A novel filamentous bacteriophage, fs-2, was isolated from Vibrio cholerae O139 strain MDO14. The fs-2 phage was a long filamentous particle 1200 nm long and 7 nm wide. The purified phage formed a turbid plaque when spotted on a lawn of the host organisms. The plaque-formation activity was stable following heating to 70 degrees C but was inhibited by treatment with chloroform. fs-2 had a single-stranded DNA genome and was converted to a double-stranded replicative form in the host cell. Almost all V. cholerae O139 and O1 El Tor biotype strains tested were sensitive to the phage, but most O1 classical strains and non-O1 non-O139 strains were resistant. The fs-2 genome comprised 8651 nucleotides containing nine open reading frames, five of which had predicted protein products partially homologous to the reported protein products of other filamentous phages. Although the extent of the homology was not particularly high, the genetic organization of other filamentous phages appears to be preserved in fs-2. The phage was not integrated into the chromosome of its host, but a 715 nucleotide fragment located in the large intergenic region of fs-2 was highly homologous to a part of region RS2 (repetitive sequence 2) of the V. cholerae CTX phi sequence which is speculated to be required for integration of the phage into the V. cholerae chromosome at a specific site. [TOP OF PAGE]

113. Virus removal by advanced membrane filtration for wastewater reclamation. Iranpour, R. (1998). Water Environment Research 70:1198-1204. Measurements of indigenous and seeded male-specific (MS2) bacteriophages were made in an effort to gain insight into the response of membrane filtration systems to varying virus concentrations and varying flow rates at the Terminal Island Treatment Plant, operated by the City of Los Angeles Bureau of Sanitation. Bacteriophages were seeded into secondary effluent that had been filtered through a trimedia filter. The seeded effluent was then processed by microfiltration (MF) and reverse osmosis (RO) pilot units for which the Department of Water and Power was evaluating effluent water quality parameters in conjunction with a water reclamation project. The samples were assayed for virus. The seeded tests utilized higher concentrations of MS2 viruses and sampled the process streams with higher time resolution than those used by other researchers in comparable experiments. As expected from the physics of RO process, the RO unit reduced the virus concentration below the threshold of detection, but the MF membranes consistently reduced virus concentrations by less than one log unit (order of magnitude). This MF performance differs from most results of similar tests carried out elsewhere, but it was consistently observed, despite substantial variability in the virus removal factor, as revealed by the high time resolution of the measurements. Budgetary limits prevented extending this research to clarify the indications in the data that removal efficiency may be affected by the MF unit's backwash cycle, or the membrane flux, but if these results can be verified, they may provide valuable insight for improved membrane technology and planning for large-scale membrane-based water reclamation. [TOP OF PAGE]

114. Mechanism of T4 Phage Restriction by a Thermosensitive Drug Resistant Factor RTSL. Ishaq, M. (1998). University of Pennsylvania. [TOP OF PAGE]

115. Targeted delivery of multivalent phage display vectors into mammalian cells. Ivanenkov, V., Felici, F., Menon, A.G. (1998). Biochim. Biophys. Acta 1448:463-472. Novel peptide motives targeting endocytosing receptors were isolated from phage display libraries of random peptides by recovering internalized phage from mammalian cells. The peptide-presenting phage selected by internalization in HEp-2 and ECV304 human cells were taken up 1000- to 100,000-fold more efficiently than their parent libraries, and from 10 to 100 times faster than phage particles displaying integrin-binding peptides. A high degree of selectivity of phage uptake was observed in these cells: phage selected in ECV304 cells were internalized approximately 100-fold more efficiently in ECV304 cells than in HEp-2 cells. Likewise, phage selected in HEp-2 cells were subsequently taken up approximately 40-fold more efficiently by HEp-2 cells than by ECV304 cells. In multiple independent trials using a cyclic peptide library, an identical peptide sequence displayed on phage was internalized by and recovered from ECV304 cells. These findings indicate that the internalization process is highly selective, and is capable of capturing a specific peptide from 2 x 10(7) peptide variants. Immunofluorescence microscopy showed juxtanuclear localization of internalized phage. These results demonstrate the feasibility of using multivalent phage-display libraries to identify new targeting ligands for the intracellular delivery of macromolecules. [TOP OF PAGE]

116. Combined use of bacteriophage typing and pulsed-field gel electrophoresis in the epidemiological analysis of Japanese isolates of enterohemorrhagic Escherichia coli O157:H7. Izumiya, A., Masuda, T., Ahmed, R., Khakhria, R., Wada, A., Terajima, A., Itoh, K., Johnson, W.M., Konuma, H., Shinagawa, K., Tamura, K., Watanabe, H. (1998). Microbiology and Immunology 42:515-519. A total of 236 enterohemorrhagic Escherichia coli (EHEC) 0157:H7 isolates in Japan were investigated by bacteriophage typing, and the results were compared with those of pulsed-field gel electrophoresis (PFGE). Seven phage types (PTs) were observed in 71 isolates which were derived from 22 outbreaks. All of the isolates from ten outbreaks in the Kinki region (midwestern part of Japan) in July-August 1996 were grouped into the same PFGE type (IIa) and PT 32, while among total isolates, there were such varieties as PFGE type IIa containing five phage types and PT32 containing two PFGE types. These results suggest that the ten outbreaks should be considered to be a single outbreak, and show that the combined use of bacteriophage typing and PFGE enhances reliability in epidemiological surveys. [TOP OF PAGE]

117. Prevalence of broad-host-range lytic bacteriophages of Sphaerotilus natans, Escherichia coli, and Pseudomonas aeruginosa. Jensen, E.C., Schrader, H.S., Rieland, B., Thompson, T.L., Lee, K.W., Nickerson, K.W., Kokjohn, T.A. (1998). Appl. Environ. Microbiol. 64:575-580. Two bacteriophage collections were examined with regard to their ability to form plaques on multiple bacterial host species. Nine of 10 phages studied were found to be broad-host-range bacteriophages. These phages fell into two groups. Group 1, the SN series, was isolated from sewage treatment plant samples with Sphaerotilus natans ATCC 13338 as a host. The DNAs of these bacteriophages contained modified bases and were insensitive to cleavage by type I and II restriction endonucleases. The efficiency of plating of these bacteriophages was changed only slightly on the alternate host. Group 2, the BHR series, was isolated by a two-host enrichment protocol. These bacteriophages were sensitive to restriction, and their efficiency of plating was dramatically reduced on the alternate host. Our results suggest that a multiple-host enrichment protocol may be more effective for the isolation of broad-host-range bacteriophages by avoiding the selection bias inherent in single-host methods. At least two of the broad-host-range bacteriophages mediated generalized transduction. We suggest that broad-host-range bacteriophages play a key role in phage ecology and gene transfer in nature. [TOP OF PAGE]

118. Characterization of marine temperate phage-host systems isolated from Mamala Bay, Oahu, Hawaii. Jiang, S.C., Kellogg, C.A., Paul, J.H. (1998). Appl. Environ. Microbiol. 64:535-542. To understand the ecological and genetic role of viruses in the marine environment, it is critical to know the infectivity of viruses and the types of interactions that occur between marine viruses and their hosts. We isolated four marine phages from turbid plaques by using four indigenous bacterial hosts obtained from concentrated water samples from Mamala Bay, Oahu, Hawaii. Two of the rod-shaped bacterial hosts were identified as Sphingomonas paucimobilis and Flavobacterium sp. All of the phage isolates were tailed phages and contained double-stranded DNA. Two of the phage isolates had morphologies typical of the family Siphoviridae, while the other two belonged to the families Myoviridae and Podoviridae. The head diameters of these viruses ranged from 47 to 70.7 nm, and the tail lengths ranged from 12 to 146 nm. The burst sizes ranged from 7.8 to 240 phage/bacterial cell, and the genome sizes, as determined by restriction digestion, ranged from 36 to 112 kb. The members of the Siphoviridae, T-f HSIC, and T-f D0, and the member of the Myoviridae, T-f D1B, were found to form lysogenic associations with their bacterial hosts, which were isolated from the same water samples. Hybridization of phage T-f HSIC probe with lysogenic host genomic DNA was observed in dot blot hybridization experiments, indicating that prophage T-f HSIC was integrated within the host genome. These phage-host systems are available for use in studies of marine lysogeny and transduction. [TOP OF PAGE]

119. Significance of lysogeny in the marine environment: studies with isolates and a model of lysogenic phage production. Jiang, S.C., Paul, J.H. (1998). Microb. Ecol. 35:235-243. The importance of lysogeny in marine microbial populations is just beginning to be understood. To determine the abundance of lysogens in bacterial populations, we studied the occurrence of lysogenic bacteria among bacterial isolates from a variety of marine environments. More than 116 bacteria isolated on artificial seawater nutrient agar plates were tested for the presence of inducible prophage by mitomycin C and UV radiation. Induction was determined as a decrease in culture absorbance at 600 nm, after treatment with inducing agents. Samples in which optical density decreased or remained the same after induction were further examined by transmission electron microscopy, for the presence of virus-like particles. More than 40% of the bacterial isolates contained inducible prophage, as determined by mitomycin C induction. A higher percentage of lysogenic bacteria was found in isolates from oligotrophic environments, compared to coastal or estuarine environments. These studies suggest that lysogenic bacteria are important components in marine microbial populations. However, a mathematical model based on viral and bacterial abundance and production rates suggests that, under normal conditions, lysogenic viral production contributes less than 0.02% of total viral production. Therefore, lysogens in the marine environment may serve as a source of viruses and only contribute significantly to viral production during natural induction events. [TOP OF PAGE]

120. Gene transfer by transduction in the marine environment. Jiang, S.C., Paul, J.H. (1998). Appl. Environ. Microbiol. 64:2780-2787. To determine the potential for bacteriophage-mediated gene transfer in the marine environment, we established transduction systems by using marine phage host isolates. Plasmid pQSR50, which contains transposon Tn5 and encodes kanamycin and streptomycin resistance, was used in plasmid transduction assays. Both marine bacterial isolates and concentrated natural bacterial communities were used as recipients in transduction studies. Transductants were detected by a gene probe complementary to the neomycin phosphotransferase (nptII) gene in Tn5. The transduction frequencies ranged from 1.33 X 10^-7 to 5.13 X 10^-9 transductants/PFU in studies performed with the bacterial isolates. With the mixed bacterial communities, putative transductants were detected in two of the six experiments performed. These putative transductants were confirmed and separated from indigenous antibiotic-resistant bacteria by colony hybridization probed with the nptII probe and by PCR amplification performed with two sets of primers specific for pQSR50. The frequencies of plasmid transduction in the mixed bacterial communities ranged from 1.58 X 10^-8 to 3.7 X 10^-8 transductants/PFU. Estimates of the transduction rate obtained by using a numerical model suggested that up to 1.3 X 10¹⁴ transduction events per year could occur in the Tampa Bay Estuary. The results of this study suggest that transduction could be an important mechanism for horizontal gene transfer in the marine environment. [TOP OF PAGE]

121. ??? Johansson, P.-O., Espeby, B., Nilsson, B., Allestam, G. (1998). pp. 383-385. In In Peters, J.H. and et al. (eds.), Artificial Recharge of Groundwater. Balkema,A.A., Rotterdam. [TOP OF PAGE]

122. Control of bacterial spot on tomato in the greehouse and field with bacteriophages. Jones, J.B., Somodi, G.C., Jackson, L.E., Harbaugh, B.K. (1998). Paper 5.2.14. Edinburgh, Scotland, 7th International Congress of Plant Pathology. [TOP OF PAGE]

123. Fluorescent Escherichia coli C for enumeration of coliphages from environmental samples. Jothikumar, N., Cliver, D.O. (1998). BioTechniques 24:546-550. [TOP OF PAGE]

124. Characterization and possible functions of a new filamentous bacteriophage from Vibrio cholerae O139. Jouravleva, E.A., McDonald, G.A., Garon, C.F., Boesman-Finkelstein, M., Finkelstein, R.A. (1998). Microbiology 144:315-324. The emergence and rapid rise to dominance of Vibrio cholerae O139 in India and Bangladesh in 1992 led to the consideration that choleraphage might serve as both a selective mechanism and a means for horizontal transmission of genetic information. A filamentous phage '493' from O139 strain AJ27-493 has been purified and partially characterized. The phage was inactive on classical biotype V. cholerae O1 but it was active on El Tor biotype strains isolated prior to 1994 when El Tor re-emerged in Bangladesh. More recent El Tor isolates were all resistant to the phage. The phage was also active on O139 strains. Unlike the filamentous ctx f, the receptor for 493 is not TcpA. The phage genome was a 9.3 kb closed circular single-stranded molecule containing a 0.4 kb double-stranded stem supporting a 2 kb single-stranded loop. A 283 bp fragment was cloned and used as a probe in Southern hybridization, in parallel with total phage 493 DNA. These probes hybridized both chromosomally and extrachromosomally with most O139 strains, but not with O1 strains. Infection of hybridization-negative El Tor or O139 strains resulted in the presence of hybridizing loci (both plasmid and chromosomal), in the appearance of an 18 kDa protein, and in marked alterations in colonial morphology. Phage 493 is clearly distinct from other O139 choleraphages which have been described. Phage 493 DNA hybridized with an encapsulated non-O1 (O31) strain (NRT36S) which was isolated before O139 was recognized. NRT36S also produces a phage which can infect El Tor strains with low efficiency. Further studies may reveal whether bacteriophage play a role in the emergence and the territoriality of new choleragenic vibrios. [TOP OF PAGE]

125. The Vibrio cholerae mannose-sensitive hemagglutinin is the receptor for a filamentous bacteriophage from V. cholerae O139. Jouravleva, E.A., McDonald, G.A., Marsh, J.W., Taylor, R.K., Boesman-Finkelstein, M., Finkelstein, R.A. (1998). Infect. Immun. 66:2535-2539. We previously isolated from a 1994 isolate of Vibrio cholerae O139 a filamentous lysogenic bacteriophage, choleraphage 493, which inhibits pre-O139 but not post-O139 El Tor biotype V. cholerae strains in plaque assays. We investigated the role of the mannose-sensitive hemagglutinin (MSHA) type IV pilus as a receptor in phage 493 infection. Spontaneous, Tn5 insertion, and mshA deletion mutants are resistant to 493 infection. Susceptibility is restored by mshA complementation of deletion mutants. Additionally, the 493 phage titer is reduced by adsorption with MSHA-positive strains but not with a DELTAmshA1 strain. Monoclonal antibody against MSHA inhibits plaque formation. We conclude that MSHA is the receptor for phage 493. The emergence and decline of O139 in India and Bangladesh are correlated with the susceptibility and resistance of El Tor strains to 493. However, mshA gene sequences of post-O139 strains are identical to those of susceptible pre-O139 isolates, indicating that phage resistance of El Tor is not due to a change in mshA. Classical biotype strains are (with rare exceptions) hemagglutinin negative and resistant to 493 in plaque assays. Nevertheless, they express the mshA pilin gene. They can be infected with 493 and produce low levels of phage DNA, like post-O139 El Tor strains. Resistance to 493 in plaque assays is thus not equivalent to resistance to infection. The ability of filamentous phages, such as 493, to transfer large amounts of DNA provides them, additionally, with the potential for quantum leaps in both identity and pathogenicity, such as the conversion of El Tor to O139. [TOP OF PAGE]

126. Bacterial and viral abundances in hydrothermal event plumes over northern Gorda Ridge. Juniper, S.K., Bird, D.F., Summit, M., Pong Vong, M., Baker, E.T. (1998). Deep-Sea Research 45:2739-2749. This study presents first-time observations of bacterial and viral abundances in hydrothermal event plumes. Two water-column event plumes were formed in conjunction with seismic events and seafloor volcanic eruptions on the northern Gorda Ridge in February--March 1996. Epifluorescence counts of bacteria and viruses were performed on water samples from 3 successive cruises staged in the 10--90 days that followed the onset of seismicity. Relative to background seawater at these 1800--3200 m depths, bacterial abundance was enhanced by 2-3 fold within both event plumes. In contrast, viral numbers were below background seawater values in the younger and more intense of the two event plumes (EP96A), and enhanced in the other (EP96B). Changes in viral abundance may be a secondary response to that of plume bacteria as well as being influenced by particle formation and precipitation within the plumes. Lower bacteria/heat, virus/heat and virus/bacteria ratios in EP96A versus EP96B confirm distinct differences in the microbial response to event plume formation, possibly related to observed differences in plume chemistry. [TOP OF PAGE]

127. The technique for the lyophilizing preservation of the plague phages. Kadetov, V.V., Kurdyakova, T.A., Terent'ev, A.N., Kachkina, G.V., Borodina, T.N., Sayamov, S.R. (1998). Biotekhnologiya 63-67. Optimum conditions for lyophilizing preservation of plague agents have been discussed which permit for them to retain the native biological characteristics under the significant reducing of the duration of the drying time. [TOP OF PAGE]

128. Phage display of a biologically active Bacillus thuringiensis toxin. Kasman, L.M., Lukowiak, A.A., Garczynski, S.F., McNall, R.J., Youngman, P., Adang, M.J. (1998). Appl. Environ. Microbiol. 64:2995-3003. [TOP OF PAGE]

129. Genetic diversity and DNA repair of marine vibriophages. Kellogg, C.A. (1998). University of South Florida, FL, USA. Viruses are the numerically dominant organisms in the global ocean. The objectives of this study investigate the dynamics of a marine bacteriophage species, the Phi 16-like vibriophages: (1) To determine the genetic diversity of vibriophage isolates from geographically diverse environments, (2) To enumerate this virus in a variety of environments and correlate the phage counts with a number of parameters, (3) To determine if the levels of spatial genetic diversity detected in the first study were comparable to the seasonal genetic variations occurring over a year at one local sampling site, (4) To study the host repair mechanisms which allow these viruses to survive inactivation by ultraviolet radiation. Sixty-nine vibriophages were isolated from waters surrounding Florida and Hawaii on Vibrio parahaemolyticus st. 16, and were determined by DNA hybridization to be genetically related. The Tampa Bay population of Phi 16-like vibriophages was positively correlated to temperature (r=0.669), but in other environments the phages also showed a dependence on bacterial abundance and a negative correlation to viral direct counts. The concentration of these phages varied seasonally in Tampa Bay, constituting a fraction of the total viral community ranging from 10^-10 to 10^-7. These viruses were primarily estuarine, although a few isolates have been found offshore and as deep as 1500 m. During the year-long genetic study in Tampa Bay, a 484 bp fragment was amplified from 165 isolates. The fragments were sorted into operational taxonomic units (OTUs) and representatives were sequenced. These sequences were compared to sequences of the geographic isolates. The genetic similarities ranged from 83% to 100%, showing that there was as much diversity temporally in Tampa Bay as there is spatially across all the sampling locations. Vibrio parahaemolyticus st. 16 clearly demonstrates photoreactivation and excision repair of the phages. Compared to V. parahaemolyticus HER1165 phages, the Phi 16-like vibriophages are more efficiently repaired, and have higher G+C contents. One HER1165 phage, which was most sensitive to UV damage and showed no photoreactivation (vp12) was found to have a G+C content of only 16%. All phage inactivation coefficients correlated with G+C content (r=0.955) suggesting that AT rich genomes are more UV sensitive. [TOP OF PAGE]

130. Viruses in Antarctic lakes. Kepner, R.L., Wharton, R.A.Jr., Suttle, C.A. (1998). Limnol. Oceanogr. 43:1754-1761. Water samples collected from four perennially ice-covered Antarctic lakes during the austral summer of 1996-1997 contained high densities of extracellular viruses. Many of these viruses were found to be morphologically similar to double-stranded DNA viruses that are known to infect algae and protozoa. These constitute the first observations of viruses in perennially ice-covered polar lakes. The abundance of planktonic viruses and data suggesting substantial production potential (relative to bacterial secondary and photosynthetic primary production) indicate that viral lysis may be a major factor in the regulation of microbial populations in these extreme environments. Furthermore, we suggest that Antarctic lakes may be a reservoir of previously undescribed viruses that possess novel biological and biochemical characteristics. [TOP OF PAGE]

131. High-temperature inducible cell-free transcription and replication of double-stranded RNAs within the parasitic protozoan Cryptosporidium parvum. Khramtsov, N.V., Upton, S.J. (1998). Virology 245:331-337. Sporozoites of the protozoan parasite, Cryptosporidium parvum, were found to contain free, full-size plus strands transcribed from two extrachromosomal, cytoplasmic, virus-like double-stranded RNAs (dsRNAs). Cell-free transcription and replication of both dsRNAs were observed in crude sporozoite lysates. RNA polymerase activity was found to be dependent upon addition of Mg2+ or Mn2+, as well as the four ribonucleoside triphosphates, and was insensitive to inhibitors of cellular DNA-dependent RNA polymerase. Semiconservative transcription of the dsRNAs (plus strand synthesis) was observed at a wide range of temperatures, with an optimum of 50 degrees C. In contrast, replication (minus strand synthesis) was detected only at 50 and 60 degrees C. [TOP OF PAGE]

132. The hunt is on for new ways to overcome bacterial resistance. Knudson, M. (1998). Technology Review 100:22-30? Researchers from various pharmaceutical companies are employing high technology approaches to develop ways to address disease-causing microbes that mutate to resist conventional antibiotics. [TOP OF PAGE]

133. Selfishness and death: Raison d'etre of restriction, recombination and mitochondria. Kobayashi, I. (1998). Trends in Genetics 14:368-374. Type II restriction-modification gene complexes, such as the EcoRI system, are not easily lost from their host cell. The descendants of cells that lose a restriction-modification gene complex are unable to modify a sufficient number of recognition sites in their chromosomes to protect them from lethal attack by the remaining molecules of restriction enzyme. This capacity to act as a selfish genetic element is likely to have contributed to the spread and maintenance of restriction-modification systems. Homologous recombination machineries of cells and viruses appear to be well adapted to cope with these elements. By extrapolation, the capacity of mitochondria to kill their host eukaryotic cell might have stabilized their initial symbiosis. [TOP OF PAGE]

134. Return of a killer. Koerner, B.I. (1998). U.S.News and World Report (November 2, 1998), 51-52. Phages may once again fight tough bacterial infections. [TOP OF PAGE]

135. Inactivation of bacteriophage lambda, Escherichia coli, and Candida albicans by ozone. Komanapalli, I.R., Lau, B.H.S. (1998). Applied Microbiology and Biotechnology 49:766-769. The effects of ozone (O₃) on three types of microbes were studied. Test suspensions were exposed to 600 ppm O₃ at room temperature. Control experiments were performed under identical conditions using oxygen gas. Bacteriophage lambda was completely inactivated at 10 min while Escherichia coli and Candida albicans were only inactivated by factors of 10⁵ and 10⁴ respectively at 40 min. Exposure of a mixed microbial suspension to O₃ for 5 min resulted in 100% killing of bacteriophages while the viability of E. coli remained unchanged. Various body fluids containing phages were exposed to O₃. Compared to buffered solution, the decrease in phage titers was significantly slower in whole blood, plasma, and albumin. Both E. coli and C. albicans had increased production of thiobarbituric-acid-reactive substances with increased O₃ exposure. ³H-labelled amino acids were incorporated into E. coli O₃ treatment resulted in a loss of radioactivity, indicating leakage of cytoplasmic contents. The data indicate that microbes are inactivated by O₃ at different rates, possibly related to differential membrane permeability. The milieu in which microbes are present determines the effectiveness and outcome of O₃ treatment. [TOP OF PAGE]

136. Soderzhanie mikroorganizmov na ottiskakh posle dezinfektsii ikh metodom pogruzheniia v rastvory gipokhlorita natriia [The microorganism count on impressions after their disinfection by submersion in sodium hypochlorite solutions]. Koshmanova, T.N., Panteleeva, L.G. (1998). Stomatologiia 77:48-49. The virucidal, bactericidal, and fungicidal activity of sodium hypochlorite is studied with silicone imprints. Poliomyelitis virus (type I vaccine strain Sabin LSc 2 ab with titer 10(7.36) TCD50/ml), bacteriophage f52 with titer 2.10(7) PFU/ml, Staphylococcus aureus strain 906, and Candida albicans in concentrations 10(7) corpuscles/ml in the presence of protein die completely in 20 min when submerged in 0.5% sodium hypochlorite solution. Imprints from alginate materials are destroyed if submerged in this solution. [TOP OF PAGE]

137. An experimental selection system to identify bacterial cells exhibiting a new DNA host specificity. Kunz, A., Meisel, A., Mackeldanz, P., Reuter, M., Krueger, D.H. (1998). Biological Chemistry 379:563-566. Restriction-modification enzymes interact with DNA sequences in a highly specific manner. Mutations within the DNA binding region of the enzymes could be expected to produce enzyme variants with changed DNA sequence specificities. We developed an efficient in vivo selection system that enabled us to detect one cell coding for a restriction-modification system with a new DNA sequence specificity in a background of more than 10⁶ cells with the original DNA sequence specificity. [TOP OF PAGE]

138. Phage Therapy: Bacteriophages as Antibiotics. Kutter, E. (1998). [TOP OF PAGE]

139. Targeting bacteriophage to mammalian cell surface receptors for gene delivery [see comments]. Larocca, D., Witte, A., Johnson, W., Pierce, G.F., Baird, A. (1998). Human Gene Therapy 9:2393-2399. Filamentous bacteriophages represent one of nature's most elegant ways of packaging and delivering DNA. In an effort to develop novel methods for ligand discovery via phage gene delivery, we conferred mammalian cell tropism to filamentous bacteriophages by attaching basic fibroblast growth factor (FGF2), transferrin, or epidermal growth factor (EGF) to their coat proteins and measuring CMV promoter-driven reporter gene expression in target cells. In this system, FGF2 was a more effective targeting agent than transferrin or EGF. The detection of green fluorescent protein (GFP) or beta-galactosidase (beta-Gal) activity in cells required FGF2 targeting and was phage concentration dependent. Specificity of the targeting for high-affinity FGF receptors was demonstrated by competing the targeted phage with FGF2, by the failure of FGF2-targeted bacteriophage to transduce high-affinity FGF receptor-negative cells, and by their ability to transduce these same cells when stably transfected with FGFR1, a high-affinity FGF receptor. Long-term transgene expression was established by selecting colonies for G418 resistance, suggesting that with the appropriate targeted tropism, filamentous bacteriophage can serve as a vehicle for targeted gene delivery to mammalian cells. [TOP OF PAGE]

140. Advanced wastewater disinfection technologies: Short and long term efficiency. Lazarova, V., Janex, M.L., Fiksdal, L., Oberg, C., Barcina, I., Pommepuy, M. (1998). Water Science and Technology 38:109-117. Advanced disinfection processes (peracetic acid, UV irradiation and ozonation) have been tested and evaluated through bench and pilot scale studies. 3 log removals of total coliforms, faecal coliforms and faecal streptococci were achieved by 10mg/L peracetic acid at a 10 min contact time, by UV radiation at 35mW.s/cm2 and by ozone at 5mg/L for 10min contact time. Higher doses are required for virus removal by UV and PAA and especially for highly resistant viruses such as F-specific bacteriophage MS2. Ozonation has the advantage of having a strong effect on all types of bacteriophages and protozoa cysts even when low treatment doses and short contact times are applied. The results of this study demonstrated that evaluation of disinfection efficiency of ozone, UV and PAA depends on the criteria and methods employed. Standard method (plate count) results showed an important disinfection effect on culturability, while results from nonstandard methods (respiratory activity and beta-galactosidase activity assay) indicated less reduction of viable cells. Moreover, the results confirm that disinfectants act on bacteria in different ways. It has been clearly demonstrated that b-galactosidase activity is affected by PAA while UV treatment has no or very limited effect on the enzyme activity. Even without sunlight reactivation, bacterial regrowth in seawater was observed after disinfection of sewage effluents. This study also shows that the biodegradability of sewage effluent for an E. coli strain was affected differently by the oxidative disinfectants ozone and PAA. Biodegradability should therefore be considered when evaluating the total disinfection efficiency. [TOP OF PAGE]

141. Inactivation of phage Qbeta by 254nm UV light and titanium dioxide photocatalyst. Lee, S., Nakamura, M., Ohgaki, S. (1998). Journal of Environmental Science and Health Part A Toxic-Hazardous Substances & Environmental Engineering 33:1643-1655. The disinfection efficacy of UV light irradiation at wavelength of 254 nm over a titanium dioxide (TiO2) suspension was compared to that of UV alone. Bacteriophage Qbeta was used as a model virus for the study. Qbeta in sterilized pure water and TiO2 suspension was irradiated by a 0.4 mW/cm2 intensity of 254nm UV light. The UV light over TiO2 was more effective than 254nm UV alone in inactivating Qbeta. 3.5-log10 Qbeta inactivation was achieved by UV irradiation over TiO2 suspension (103 mg/L) after 2 minutes of irradiation, while UV alone inactivated 2-log10. Using a MPN-PCR method, a ca. 1-log10-unit decrease in Qbeta RNA concentration was detected after 3 minutes of photocatalytic irradiation. Th. decrease was explained by damage to nucleic acid of phage Qbeta due to radical oxidation, which is generated by photocatalysis. [TOP OF PAGE]

142. Distribution of indicator bacteria and bacteriophages in shellfish and shellfish-growing waters. Legnani, P., Leoni, E., Lev, D., Rossi, R., Villa, G.C., Bisbini, P. (1998). Journal of Applied Microbiology 85:790-798. Shellfish (mussels and clams) and shellfish-growing waters were examined for indicator bacteria according to the EC regulations, Salmonella spp., coliphages and anti-Salmonella phages. Samples were collected both from natural-growing areas along the coast and from authorized shellfish-harvesting beds. The coastal area was affected by organic pollution and extensive faecal contamination and, according to the legal requirements, was unsuitable for shellfish farming. The shellfish collected along the coast also showed faecal contamination at levels which did not conform to legal standards. No significant differences were observed between the frequency of isolation of somatic coliphages and indicator bacteria from sea water. In contrast, both the authorized and wild coastal shellfish were contaminated by coliphages at a significantly higher level than the corresponding bacteria) indicators for faecal contamination (chi2 test, P < 0.01), waters (P < 0.001), and sediments (P < 0.05), but no correlation was found in shellfish, thus Coliphage concentrations were significantly correlated with faecal indicators in marine of economic importance. [TOP OF PAGE]

143. Involvement of a prophage in the lysis of Lactococcus lactis subsp. cremoris AM2 during cheese ripening. Lepeuple, A.S., Vassal, L., Cesselin, B., Delacroix-Buchet, A., Gripon, J.C., Chapot-Chartier, M.P. (1998). International Dairy Journal 8:667-674. Lactococcus lactis subsp. cremoris AM2 strain was previously shown to lyse early and extensively during cheese ripening. This strain is lysogenic and contains a prophage named PHIAM2. Lysis of strain AM2 and its prophage-cured derivative AM2-C in Saint-Paulin pressed-type cheese was monitored by the following parameters: cell viability, morphological changes of bacteria observed by electron microscopy and release of intracytoplasmic peptidases. Proteolysis was quantified by measuring soluble nitrogen (SN), phosphotungstic acid soluble nitrogen (PTA-N) and free amino acids. By contrast to the wild type strain AM2 which lyses early and extensively, its prophage-cured derivative AM2-C lyses only slowly and to a limited extent in cheese. These results indicate that the prophage PHIAM2 is involved in the lytic behaviour of L. lactis AM2 during cheese ripening. In addition, the comparison of two isogenic strains with similar enzymatic potential but different ability to lyse demonstrates that starter strain lysis results in a higher free amino acids production rate and a decrease of bitter taste. [TOP OF PAGE]

144. Reconstruction of the presumptive mechanisms of bacteriophage speciation and morphological evolution. Letarov, A.V. (1998). Genetika 34:1461-1469. The problem of the origin and evolution of viruses and, in particular, the origin and evolution of bacteriophages is of considerable interest. However, so far, this problem has not been solved with quantitative methods of molecular systematics. In the present study, an attempt to reconstruct the possible paths of appearance and evolution of bacteriophages based on their structural features and morphogenesis, as well as general characteristics of their life cycles and genome organization, was carried out. A scheme describing phylogeny of the main bacteriophage groups and evolution of their life cycles is suggested. Existence of two independently evaluating types of morphogenesis ("budding outward" and "budding inward") is postulated. [TOP OF PAGE]

145. The challenge of antibiotic resistance. Levy, S.B. (1998). Scientific American (March), 46-53. Certain bacterial infections now defy all antibiotics. The resistance problem may be reversible, but only if society begins to consider how the drugs affect "good" bacteria as well as "bad". [this, technically, is not a bacteriophage ecology reference, but I'm including it in the BEG bibliography for those interested in questions of why bacteriophage therapy may again possess relevance; three volumes are referenced by this article which also address the antibiotic issue, and these, too, are now referenced by the BEG bibliography - STA]. [TOP OF PAGE]

146. An evolutionary link between sporulation and prophage induction in the structure of a repressor:anti-repressor complex. Lewis, R.J., Brannigan, J.A., Offen, W.A., Smith, I., Wilkinson, A.J. (1998). J. Mol. Biol. 283:907-912. Spore formation is an extreme response of some bacteria to adversity. In Bacillus subtilis the proteins of the sin, sporulation inhibition, region form a component of an elaborate molecular circuitry that regulates the commitment to sporulation. SinR is a tetrameric repressor protein that binds to the promoters of genes essential for entry into sporulation and prevents their transcription. This repression is overcome through the activity of SinI, which disrupts the SinR tetramer through the formation of a SinI-SinR heterodimer. The interactions governing this curious quaternary transition are revealed in the crystal structure of the SinI-SinR complex. The most striking, and unexpected, finding is that the tertiary structure of the DNA-binding domain of SinR is identical with that of the corresponding domains of the repressor proteins, CI and Cro, of bacteriophage 434 that regulate lysis/lysogeny. This structural similarity greatly exceeds that between SinR and any bacterial protein or between the 434 repressor proteins and their homologues in the closely related bacteriophage lambda. The close evolutionary relationship implied by the structures of SinR and the 434 repressors provokes both comparison of their functions and a speculative consideration of the intriguing possibility of an evolutionary link between the two adaptive responses, sporulation and prophage induction. [TOP OF PAGE]

147. A new and simple method for concentration of enteric viruses from water. Li, J.W., Wang, X.W., Rui, Q.Y., Song, N., Zhang, F.G., Ou, Y.C., Chao, F.H. (1998). Journal of Virological Methods 74:99-108. A new type of electropositive filter media particle was tested to adsorb bacteriophage f2 and enteric viruses from tap water. 3 x nutrient broth (pH 7.2) was used to elute the adsorbed viruses, and the eluate was reconcentrated by polyethylene glycol (Mw 6000) precipitation with a final concentration of 10% (wt./vol.). The adsorption of bacteriophage was reliable and efficient, and not affected by the pH value, temperature, turbidity and organic materials in water. This method gave a recovery of Polio 1 virus 96.0% for small-volume tap water; 88.7% for large-volume water; and gave a comparable recovery of HAV, Coxsackie B3 and Echo 7 from tap water. The concentration method need not acidify virus-containing water, add exogenous multivalent cation salts, or require expensive equipment. [TOP OF PAGE]

148. Complete DNA sequence and detailed analysis of the Yersinia pestis KIM5 plasmid encoding murine toxin and capsular antigen. Lindler, L.E., Plano, G.V., Burland, V., Mayhew, G.F., Blattner, F.R. (1998). Infect. Immun. 66:5731-5742. Yersinia pestis, the causative agent of plague, harbors at least three plasmids necessary for full virulence of the organism, two of which are species specific. One of the Y. pestis-specific plasmids, pMT1, is thought to promote deep tissue invasion, resulting in more acute onset of symptoms and death. We determined the entire nucleotide sequence of Y. pestis KIM5 pMT1 and identified potential open reading frames (ORFs) encoded by the 100,990-bp molecule. Based on codon usage for known yersinial genes, homology with known proteins in the databases, and potential ribosome binding sites, we determined that 115 of the potential ORFs which we considered could encode polypeptides in Y. pestis. Five of these ORFs were genes previously identified as being necessary for production of the classic virulence factors, murine toxin (MT), and the fraction 1 (F1) capsule antigen. The regions of pMT1 encoding MT and F1 were surrounded by remnants of multiple transposition events and bacteriophage, respectively, suggesting horizontal gene transfer of these virulence factors. We identified seven new potential virulence factors that might interact with the mammalian host or flea vector. Forty-three of the remaining 115 putative ORFs did not display any significant homology with proteins in the current databases. Furthermore, DNA sequence analysis allowed the determination of the putative replication and partitioning regions of pMT1. We identified a single 2,450-bp region within pMT1 that could function as the origin of replication, including a RepA-like protein similar to RepFIB, RepHI1B, and P1 and P7 replicons. Plasmid partitioning function was located ca. 36 kb from the putative origin of replication and was most similar to the parABS bacteriophage P1 and P7 system. Y. pestis pMT1 encoded potential genes with a high degree of similarity to a wide variety of organisms, plasmids, and bacteriophage. Accordingly, our analysis of the pMT1 DNA sequence emphasized the mosaic nature of this large bacterial virulence plasmid and provided implications as to its evolution. [TOP OF PAGE]

149. Bacteriophage and gene transfer. Lindqvist, B.H. (1998). APMIS. SUPPLEMENTUM 84:15-18. [TOP OF PAGE]

150. Defective phage as an antagonistic factor of closely related bacilli. Lotareva, O.V., Prozorov, A.A. (1998). Mikrobiologiya 67:788-791. The antagonistic effect produced by the defective phage PBSX during cocultivation of the mutant strain B. subtilis 168, in which this phage is heat-inducible, and strain B. subtilis NRS231, which also bears a defective phage, was investigated. As soon as in the first hours of cocultivation under conditions of PBSX induction, the number of viable cells of strain NRS231 decreased by two orders of magnitude. However, the effect was not observed if the temperature of cocultivation was noninducing. The results confirm the supposition that defective phages may play a role in the competition between closely related bacilli. [TOP OF PAGE]

151. The structural gene module in Streptococcus thermophilus bacteriophage f Sfi11 shows a hierarchy of relatedness to Siphoviridae from a wide range of bacterial hosts. Lucchini, S., Desiere, F., Brussow, H. (1998). Virology 246:63-73. The structural gene cluster and the lysis module from lytic group II Streptococcus thermophilus bacteriophage f Sfi11 was compared to the corresponding region from other Siphoviridae. The analysis revealed a hierarchy of relatedness. f Sfi11 differed from the temperate S. thermophilus bacteriophage f O1205 by about 10% at the nucleotide level. The majority of the changes were point mutations, mainly at the third base position. Only a single gene (orf 695) differed substantially between the two phages. Over the putative minor tail and lysis genes, f Sfi11 and the lytic group 1 S. thermophilus f Sfi19 shared regions with variable degrees of similarity. Orf 1291 from f Sfi19 was replaced by four genes in f Sfi11, two of which (orf 1000 and orf 695) showed a complicated pattern of similarity and nonsimilarity compared with f Sfi19. The predicted orf 695 gp resembles the receptor-recognizing protein of T-even coliphages in its organization, but not its sequence. No sequence similarity was detected between f Sfi11 and f Sfi19 in the region covering the major head and tail genes. Comparison of the structural gene map of f Sfi11 with that of Siphoviridae from gram-positive and -negative bacterial hosts revealed a common genomic organization. Sequence similarity was only found between f Sfi11 and Siphoviridae from gram-positive hosts and correlated with the evolutionary distance between the bacterial hosts. Our data are compatible with the hypothesis that the structural gene operon from Siphoviridae of the low G + C group of gram-positive bacteria is derived from a common ancestor. [TOP OF PAGE]

152. Virus binding to brown algal spores and gametes visualized by DAPI fluorescence microscopy. Maier, I., Mueller, D.G. (1998). Phycologia 37:60-63. Several brown algae (Phaeophyceae) have been found to be regularly parasitized by viruses. These viruses are icosahedral, 120-180 nm in diameter, and have large genomes of double-stranded DNA in the range of 160-340 k base pairs (kbp). Their natural host range appears to be relatively narrow (Ivey et al. 1996; Mueller 1996; Kapp et al. 1997). Coleman et al. (1981) employed DAPI (4',6-diamidino-2-phenylindole) fluorescence staining for visualization and microspectrophotometric measurement of individual T₄ bacteriophage DNA, which is smaller than most brown algal viral genomes (166 kbp). Therefore, we expected this method to be sensitive enough for the localization of brown algal virus particles bound to their host cells. Stained virions could also be used to show if host specificity is reflected by the level of virus binding. [TOP OF PAGE]

153. Resistance of Pseudomonas aeruginosa PAO1 phage F116 to sodium hypochlorite. Maillard, J.Y., Hann, A.C., Perrin, R. (1998). Journal of Applied Microbiology 85:799-806. The development of viral resistance to sodium hypochlorite was investigated using the Pseudomonas aeruginosa bacteriophage F116 as a model system. This phage was chosen because of its structural characteristics and former investigations conducted in this laboratory. F116 was shown to be sensitive to a sodium hypochlorite concentration of 0.0075 g l^-1 (available chlorine) which produced a 5 log10 reduction in titre in a suspension test. Survival bacteriophages challenged with this sodium hypochlorite concentration were isolated, propagated and challenged again with the same and higher concentrations of the biocide. It was observed that progeny virions were becoming increasingly resistant to sodium hypochlorite challenges up to a concentration of 0.0175 g l-1 of available chlorine. It was also noticed that 1-2 log10 of F116 virions from resistant phage lysates remained sensitive to the biocide. An electron microscopical investigation of F116 resistant lysates showed that the phage resistance to sodium hypochlorite was not caused by F116 particles aggregation. Furthermore, no morphological difference between the sensitive and resistant F116 particles to sodium hypochlorite was identified. [TOP OF PAGE]

154. Elevated production of dimethylsulfide resulting from viral infection of cultures of Phaeocystis pouchetii. Malin, G., Wilson, W.H., Bratbak, G., Liss, P.S., Mann, N.H. (1998). Limnol. Oceanogr. 43:1389-1393. [TOP OF PAGE]

155. Taxonomy of bacterial viruses: establishment of tailed virus genera and the order Caudovirales [news]. Maniloff, J., Ackermann, H.-W. (1998). Archives in Virology 143:2051-2063. [TOP OF PAGE]

156. Cloning and sequencing of major capsid protein (mcp) gene of a vibriophage, KVP20, possibly related to T-even coliphages. Matsuzaki, S., Inoue, T., Kuroda, M., Kimura, S., Tanaka, S. (1998). Gene 222:25-30. A large, tailed, prolate-headed vibriophage designated KVP20 was isolated from seawater. KVP20 was morphologically very similar to the previously described vibriophage, KVP40 (Matsuzaki, S., Inoue, T., Tanaka, S., 1998. Virology, 242, 314-318). However, they showed entirely different host specificities and could easily be differentiated from each other by their patterns of DNA restriction fragments. The major capsid protein (mcp) gene of KVP20 encoding the precursor of major capsid protein (pro-Mcp) was cloned and sequenced. The deduced amino-acid (aa) sequence of KVP20 pro-Mcp was compared with the reported aa sequences of KVP40 pro-Mcp, as well as of the equivalent proteins (gp23s) of coliphages T4 and RB49. There was 96.7, 57.5, and 55.2% homology to the corresponding proteins of KVP40, T4, and RB49, respectively. These data strongly suggest that the two vibriophages are closely related to each other and that they are both distantly, but definitely, related to coliphages T4 and RB49. [TOP OF PAGE]

157. Characterization of a novel cis-syn and trans-syn-II pyrimidine dimer glycosylase/AP lyase from a eukaryotic algal virus, Paramecium bursaria chlorella virus-1. McCullough, A.K., Romberg, M.T., Nyaga, S., Wei, Y., Wood, T.G., Taylor, J.S., Van Etten, J.L., Dodson, M.L., Lloyd, R.S. (1998). Journal of Biological Chemistry [J. Biol. Chem. ] 273:13136-13142. Endonuclease V from bacteriophage T4, is a cis-syn pyrimidine dimer-specific glycosylase. Recently, the first sequence homolog of T4 endonuclease V was identified from chlorella virus Paramecium bursaria chlorella virus-1 (PBCV-1). Here we present the biochemical characterization of the chlorella virus pyrimidine dimer glycosylase, cv-PDG. Interestingly, cv-PDG is specific not only for the cis-syn cyclobutane pyrimidine dimer, but also for the trans-syn-II isomer. This is the first trans-syn-II-specific glycosylase identified to date. Kinetic analysis demonstrates that DNAs containing both types of pyrimidine dimers are cleaved by the enzyme with similar catalytic efficiencies. Cleavage analysis and covalent trapping experiments demonstrate that the enzyme mechanism is consistent with the model proposed for glycosylase/AP lyase enzymes in which the glycosylase action is mediated via an imino intermediate between the C1' of the sugar and an amino group in the enzyme, followed by a beta -elimination reaction resulting in cleavage of the phosphodiester bond. cv-PDG exhibits processive cleavage kinetics which are diminished at salt concentrations greater than those determined for T4 endonuclease V, indicating a possibly stronger electrostatic attraction between enzyme and DNA. The identification of this new enzyme with broader pyrimidine dimer specificity raises the intriguing possibility that there may be other T4 endonuclease V-like enzymes with specificity toward other DNA photoproducts. [TOP OF PAGE]

158. Synergistic effects of abiE or abiF from pNP40 when cloned in combination with abiD from pBF61. McLandsborough, L.A., Sechaud, L., McKay, L.L. (1998). Journal of Dairy Science 81:362-368. Two fragments conferring partial phage resistance were located on plasmid pNP40 from Lactococcus lactis ssp. lactis biovar diacetylactis DRC3 and cloned. A 2.3-kb PstI fragment from pNP40 containing abiF conferred partial phage resistance to prolate-headed phage c2, and a 4.8-kb PstI fragment of pNP40 containing abiE conferred partial phage resistance to small isometric-headed phage sk1. When each of the two fragments was cloned individually into a plasmid containing the abortive phage infection gene abiD from L. lactis ssp. lactis KR5, phage resistance was enhanced. When cloned with abiD, the 2.3-kb PstI fragment enhanced the resistance against prolate-headed phages, as was indicated by a 400-fold decrease in the efficiency of plating compared with that of abiD alone. When the 4.8-kb PstI fragment of pNP40 was cloned with abiD, resistance to small isometric-headed phages was enhanced, as was indicated by a greater than 50-fold decrease in efficiency of plating compared with that of abiD alone. The 4.8-kb PstI fragment of pNP40 cloned with abiD showed a large decrease (500- to 1000-fold) in efficiency of plating against prolate-headed phages, even though the 4.8-kb PstI fragment of pNP40 by itself conferred no resistance to the prolate-headed phages. [TOP OF PAGE]

159. Evidence of pseudolysogeny in a marine phage host system. McLaughlin, M.R., Paul, J.H. (1998). Abstracts of the General Meeting of the American Society for Microbiology 98:387-??? [TOP OF PAGE]

160. Inactivation of mycobacteriophage D29 using ferrous ammonium sulphate as a tool for the detection of viable Mycobacterium smegmatis and M. tuberculosis. McNerney, R., Wilson, S.M., Sidhu, A.M., Harley, V.S., Al Suwaidi, Z., Nye, P.M., Parish, T., Stoker, N.G. (1998). Res. Microbiol. 149:487-495. There is still an urgent requirement for more sensitive, cost-effective methods for detection and susceptibility testing of mycobacteria in clinical samples. We have been investigating a simple bacteriophage-based system which could be used for both purposes. As this depends upon the detection of phages which have successfully infected cells, a key step is the efficient removal or inactivation of phages remaining free in the culture medium. We demonstrate here the use of ferrous ammonium sulphate as an effective agent for the inactivation of mycobacteriophage D29 without impairing phage replication in previously infected host bacteria. Using this property, we report the detection of viable Mycobacterium smegmatis, M. bovis BCG and M. tuberculosis using simple low-cost technology. The method is highly sensitive, since it is able to detect 10 colony-forming units of M. smegmatis. It is also rapid, with the detection of M. tuberculosis in sputum specimens within 48 h. [TOP OF PAGE]

161. Principles of virus-directed regulation of formation of the dynamic system virus-cell (problems, methodology and prospects of cyanophagia). Mendzhul, M.I., Lysenko, T.G., Koltukova, N.V., Syrchin, S.A., Sukhanov, S.N. (1998). Mikrobiolohichnyi Zhurnal 60:66-78. Dynamics of virus-directed regulation of formation of the complex virus - cell has been studied on the example of the system cyanophage-cyanobacterium. It is shown that in the process of virus reproduction the host-cell loses its own genetic apparatus, system of regulation of biosynthetic processes, reproductive ability and other functions of vital importance. As a matter of fact the formed virus - cell complex turns into powerful generator of nucleotides and amino acids for nonlimited synthesis of virus nucleic acids, proteins and morphogenesis of virions. The question is discussed concerning the possibility of the use of the system cyanophage cyanobacterium as the experimental models for development of functional unified model of productive infection, effective methods of prophylaxis and therapy of virus infections as well as the decision of various biotechnological problems. [TOP OF PAGE]

162. Bacteriophage PM2 nomenclature revision. Merino, S., Tomas, J.M., Maniloff, J. (1998). Archives of Virology 143:1852-1853. Two taxonomically different bacteriophages have unintentionally been given the same name. Alteromonas phage PM2, isolated in 1968, is the type species of the family Corticoviridae, genus Corticovirus: lipid-containing, icosahedral viruses containing circular dsDNA. Aeromonas phage PM2, isolated in 1990, is a tailed virus, with contractile tail, and presumably a member of the family Myoviridae: phages with contractile tails, containing linear dsDNA. To avoid confusion, the name of Aeromonas phage PM2 is now changed to phage AehPM2. [TOP OF PAGE]

163. Comparative survival of F+ RNA coliphages, poliovirus type 1(PV1), and somatic salmonella phage (SSP) in advanced treated wastewater, groundwater and soil suspensions. Meschke, J.S., Sobsey, M.D. (1998). Abstracts of the General Meeting of the American Society for Microbiology 98:443-444. [TOP OF PAGE]

164. Comparative adsorption of Norwalk virus, poliovirus 1 and F+ RNA coliphage MS2 to soils suspended in treated wastewater. Meschke, J.S., Sobsey, M.D. (1998). Water Science and Technology 38:187-189. Enteric viruses such as Norwalk virus (NV) are important agents of waterborne disease from faecally contaminated groundwater. Viruses are more resistant to inactivation than most enteric bacteria and they may not be removed efficiently during land application. Adsorption is one of the major factors in viral removal and persistence in soils. The adsorption of NV by soils suspended in wastewater has not been determined. Therefore, we determined the adsorption of NV to six soils (Cecil clay-loam, Corolla sand, Georgia Kaolinite (clay), Wyoming Bentonite (clay), Ponzer organic muck and Flushing Meadows sand-loam) suspended in treated wastewater and compared it to that of poliovirus 1 (PV1) (strongly adsorbed) and MS2 (weakly adsorbed). NV is shown to be less sorptive than PV1 and more sorptive than MS2. Furthermore, relative virus adsorption among soils was similar for all three enteric viruses with viruses most adsorbed by clays and least adsorbed by sand and organic soils. [TOP OF PAGE]

165. Advance in bacterial typing methods (a review). Milch, H. (1998). Acta Microbiol. Immunol. Hungarica 45:401-408. We give a short review about the two main groups of bacterial typing methods for epidemiological purposes: the phenotypic and genotypic methods. The advantage of the phenotypic methods is their feasibility for the less equipped laboratories, their disadvantages are the variability of the phenotypic properties, and their high labor requirement. The advantages of the genotypic typing methods are the higher discriminatory power and applicability of the same method for different species of bacteria. The disadvantage of these methods is that they are expensive and labour consuming. Beside the short description, we show the results of different authors obtained by the use of the molecular methods in the epidemiological practice and we call the attention to the insufficiency concerning the stability. [TOP OF PAGE]

166. Application and evaluation of male-specific bacteriophage as a process integrity or faecal contamination indicator in a pork slaughterhouse environment. Miller, A.J., Eblen, B.S., Oser, A., Burkhardt, W.3. (1998). Journal of Applied Microbiology 85:898-904. A male-specific bacteriophage plaque assay was evaluated as a faecal contamination or process integrity indicator for aspects of the pork slaughter process. Over 400 samples were tested including: sponge swabs from animal hauling trailer floors and dressed carcass surfaces; faecal material; water from slaughter sites; and water from each stage of wastewater treatment. Bacteriophage were observed in wastewater, trailers, slaughter process water and swine faeces. No bacteriophage were observed on dressed carcasses. Numbers of phage plaque-forming units per gram or millilitre showed greater variation and were usually lower than standard indicators, including total coliform or Escherichia coli counts. Among the applications studied, male-specific bacteriophage appear to be best suited for process control verification for wastewater treatment. [TOP OF PAGE]

167. Bacterial gene swapping in nature. Miller, R.V. (1998). Scientific American 278:66-71. Genes travel between independent bacteria more often than once was assumed. Study of that process can help limit the risks of releasing genetically engineered microbes into the environment. [TOP OF PAGE]

168. Isotopic tracers for characterizing artificial recharge and tracking water quality changes. Moran, J.E., Davisson, M.L., Halliwell, M., Hudson, G.B., Koester, C., Niemeyer, S. (1998). Abstracts with Programs - Geological Society of America 30:22 Tracer methods using natural isotope abundances in water and artificially introduced noble gas tracers have been developed and successfully applied to an artificial recharge project in the San Francisco Bay area of California. These methods provide quantitative results for groundwater recharge rates, groundwater residence times, and the extent of mixing with ambient basin groundwater. Simultaneous determination of various water quality parameters, including total organic carbon, nitrate, major and trace metals, pathogens, and some organic compounds including methyl tert butyl ether (MTBE; a gasoline additive) allows characterization of the fate of these compounds during infiltration and subsurface flow. In an effort to prevent seawater intrusion, and to augment water supply, approximately 40 billion liters of water per year is artificially recharged through surface spreading ponds and an adjacent creek in recharge facilities of an East Bay water district. Production wells are located 500 to 800 m downgradient. Groundwater ages were determined for several production wells by the tritium-helium method and give mean ages of 3 to 30 years, and show a pattern of increasing age with depth. In addition, a series of isotopically enriched xenon isotope tracers were introduced into spreading ponds and monitored weekly in downgradient wells. An initial pulse of highly diluted tracer arrived very quickly (corresponding to a groundwater velocity of 2700 m/yr.) and suggests a highly dispersive medium, and high hydraulic conductivity for basin sediments (given the low hydraulic gradient prevalent during the course of the study). The bulk of the tracer traveled more slowly, consistent with mean residence times of a few years, as indicated by groundwater ages. Improvement to water quality through groundwater recharge is indicated by elimination of male-specific coliphage, a large reduction in total organic carbon, and a reduction in some trace metals including Al, Fe, Sb, U, and V. Nitrate levels decrease slightly during recharge, while total dissolved solids levels increase slightly. MTBE is ubiquitous at very low levels in surface water (hundreds of ppt) and groundwater (tens of ppt), due to atmospheric deposition and runoff. Significantly lower levels of MTBE detected in somewhat older water may be due to dilution with water recharged before the time of increased use of MTBE as a gasoline additive. [TOP OF PAGE]

169. Elemental composition of individual pico- and nano-sized marine detrital particles in the northwestern Mediterranean Sea. Mostajir, B., Fagerbakke, K.M., Heldal, M., Thingstad, T.F., Rassoulzadegan, F. (1998). Oceanologica Acta 21:589-596. The elemental composition of individual < 10 mu m detrital particles from Mediterranean surface waters was analysed using a Transmission Electron Microscope (TEM) equipped with an energy dispersive X-Ray microanalyser. Results show that carbon and phosphorus content per detritus volume are much higher in pico-detrital particles < 2 mu m (42 kg C m(-3) and 1 kg P m(-3)) than in 5-10 mu m detrital particles (20 kg C m-3 and 0.1 kg P m(-3)). The C:N:P atomic ratios for different sized fractions of the detrital particles were found to be 82:10:1 for < 2 mu m particles, 120:29:1 for 2-5 mu m particles and 308:37:1 for 5-10 mu m particles. The average ratio for all size classes of detrital particles (< 10 mu m) was 132:23:1. The differences in elementary compositions of the detrital particles studied here suggest that the different size fractions probably have different origins. The role and origins of < 10 mu m detrital particles within the biogeochemical cycles are discussed. (C) Elsevier, Paris. [TOP OF PAGE]

170. Abundance in sewage of bacteriophages that infect Escherichia coli 0157:H7 and that carry the Shiga toxin 2 gene. Muniesa, M., Jofre, J. (1998). Appl. Environ. Microbiol. 64:2443-2448. Shiga toxin-converting bacteriophages are involved in the pathogenicity of some enteric bacteria, such as Escherichia coli O157:H7, but data on the occurrence and distribution of such phages as free particles in nature were not available. An experimental approach has been developed to detect the presence of the Shiga toxin 2 (Stx 2)-encoding bacteriophages in sewage. The Stx 2 gene was amplified by PCR from phages concentrated from 10-ml samples of sewage. Moreover, the phages carrying the Stx 2 gene were detected in supernatants from bacteriophage enrichment cultures by using an Stx 2-negative E. coli O157:H7 strain infected with phages purified from volumes of sewage as small as 0.02 mi. Additionally, the A subunit of Stx 2 was detected in the supernatants of the bacteriophage enrichment cultures, which also showed cytotoxic activity for Vero cells. By enrichment of phages concentrated from different volumes of sewage and applying the most-probable-number technique, it was estimated that the number of phages infectious for E. coli O157:H7 and carrying the Stx 2 gene was in the range of 1 to 10 per ml of sewage from two different origins. These values were approximately 1% of all phages infecting E. coli O157:H7. [TOP OF PAGE]

171. Effect of temperature on the algicidal activity and the satability of HaV (Heterosigma akashiwo virus). Nagasaki, K., Yamaguchi, M. (1998). Aquat. Microb. Ecol. 15:211-216. The effect of temperature on the algicidal activity and stability of HaV (Heterosigma akashiwo virus), which infects the harmful bloom causing alga, H. akashiwo (Raphidophyceae), was determined by growing H. akashiwo culture inoculated with HaV under various conditions. Temperature and growth stage of the host culture are considered to be important factors determining the algicidal activity of HaV. The optimum temperature for the algicidal activity of HaV ranged from 20 to 25 degrees C. Comparing the viral susceptibility of H. akashiwo strains and the algicidal activity of the HaV clones at different temperatures, both were suggested to be phenotypically diverse. Effect of temperature on the stability of HaV was also evaluated. HaV showed a relatively rapid decrease in infectious titer even when preserved at 5 degrees C in the dark. The data is discussed in relation to the behavior of HaV in natural environments and the disintegration mechanism of H. akashiwo red tide. [TOP OF PAGE]

172. Intra-species host specificity of HaV (Heterosigma akashiwo virus) clones. Nagasaki, K., Yamaguchi, M. (1998). Aquat. Microb. Ecol. 14:109-112. [TOP OF PAGE]

173. A temperate phage with cohesive ends induced by mitomycin C treatment of Lactobacillus casei. Nakashima, Y., Hasuwa, H., Kakita, Y., Murata, K., Kuroiwa, A., Miake, F., Watanabe, K. (1998). Archives of Virology 143:1621-1626. [TOP OF PAGE]

174. Filamentous phage fs1 of Vibrio cholerae O139. Nakasone, N., Honma, Y., Toma, C., Yamashiro, T., Iwanaga, M. (1998). Microbiology and Immunology 42:237-239. Filamentous phage, fs1, was obtained from Vibrio cholerae O139. The lysogenized strains produced a large amount of fs1 phage in the culture supernatant. This phage was previously reported as novel fimbriae of that organism. The genome of the phage was a 6.5 kb single-stranded DNA. The capsid of fsl consists of a small molecule peptide (about 2.5 kDa). [TOP OF PAGE]

175. Comparison of the lysogeny modules from the temperate Streptococcus thermophilus bacteriophages TP-J34 and Sfi21: implications for the modular theory of phage evolution. Neve, H., Zenz, K.I., Desiere, F., Koch, A., Heller, K.J., Brussow, H. (1998). Virology 241:61-72. A 7.6-kb DNA segment covering the putative lysogeny module of the pac-site-containing temperate Streptococcus thermophilus bacteriophage TP-J34 was sequenced. Sequence alignment with the lysogeny module from the cos-site-containing S. thermophilus bacteriophage fSfi21 revealed areas of high sequence conservation (e.g., over the int gene), interspersed with regions of low or no sequence similarity (e.g., over the cro gene). Four of the six sharp transition zones from high to low sequence conservation were found within open reading frames coding for the CI repressor, the Anti-repressor, the Immunity protein, and a protein of unknown function. The transition points in the cI and ant genes appear to separate gene segments coding for distinct functional domains of these proteins. In addition, these two transition points were located at or near the deletion sites observed in spontaneous phage fSfi21 deletion mutants, thus suggesting these transition points as recombinational hotspots. Furthermore, the sequence at the transition point in the cI gene resembles the attachment site of the phage, suggesting the involvement of the phage integrase in at least some of the exchange reactions. Contrary to the initial formulation of the modular theory of phage evolution the unit of the evolutionary exchange in streptococcal phages is not a group of functional genes, but can be as small as a single gene. Exchange reactions can also occur within genes, possibly between gene segments encoding distinct protein domains. [TOP OF PAGE]

176. Long term use of a Cheddar starter and development of phages with homology to its bacteria. Nielsen, E.W. (1998). International Dairy Journal 8:1003-1009. A mixed, homofermentative, mesophilic starter was used for more than 11 years as the only starter for production of Cheddar cheese at a Danish cheese factory. The activity of the starter at the factory was carefully recorded, and whey samples were regularly tested for bacteriophages. During the years bacteriophages, homologous to an increasing number of the strains of the starter culture, gradually evolved. After 4 years bacteriophages, homologous to more than 50%-and after 6 years to more than 90%-of 62 bacterial isolates from the starter, had appeared. For most of the strains the virulence of their phages was low at first and thereafter increased over several years. It was, however, only after more than 11 years that the cheese factory first began to observe cases of reduced activity of the bulk starter; presumably because the virulence of the bacteriophages had developed to such a degree that very low levels of contamination of the milk for bulk starter could impair the subsequent activity of the bulk starter in the curd. [TOP OF PAGE]

177. Group I introns found in Chlorella viruses: biological implications. Nishida, K., Suzuki, S., Kimura, Y., Nomura, N., Fujie, M., Yamada, T. (1998). Virology 242:319-326. More than 80 group I introns were detected and characterized in Chlorella viruses isolated from various locations in Japan; the overall average frequency of viruses containing the group I intron was 8.0%. Although most of these introns were inserted in the gene for either transcriptional elongation factor TFIIS (approximately 60%) or URF 14.2 (unidentified open reading frame coding for a 14.2-kDa polypeptide) (approximately 40%), in a few cases, the gene for the major capsid protein Vp52 contained an intron. These introns were biologically active (self-splicing) both in vivo and in vitro. Viruses that contained introns almost usually contained only one, but more than two introns coexisted in several virus isolates. Nucleotide sequence analysis showed that the intron sequences have diverged under strong constraint of the exon genes: introns in the same gene showed more than 99% sequence identity, whereas introns in different genes were only 72-78% identical. Phylogenetic analysis suggested relatedness of these introns to those found in the rRNA genes of a variety of organisms including green algae, red algae, red algae, yeasts, fungi, and protozoa. [TOP OF PAGE]

178. Use of SYBR Green I for rapid epifluorescence counts of marine viruses and bacteria. Noble, R.T., Fuhrman, J.A. (1998). Aquat. Microb. Ecol. 14:113-118. A new nucleic acid stain, SYBR Green I, can be used for the rapid and accurate determination of viral and bacterial abundances in diverse marine samples. We tested this stain with formalin-preserved samples of coastal water and also from depth profiles (to 800 m) from sites 19 and 190 km offshore, by filtering a few ml onto 0.02 mu m pore-size filters and staining for 15 min. Comparison of bacterial counts to those made with acridine orange (AO) and virus counts with those made by transmission electron microscopy (TEM) showed very strong correlations. Bacterial counts with AO and SYBR Green I were indistinguishable and almost perfectly correlated (r super(2) = 0.99). Virus counts ranged widely, from 0.03 to 15 x 10 super(7) virus ml super(-1). Virus counts by SYBR Green I were on the average higher than those made by TEM, and a SYBR Green I versus TEM plot yielded a regression slope of 1.28. The correlation between the two was very high with an r super(2) value of 0.98. The precision of the SYBR Green I method was the same as that for TEM, with coefficients of variation of 2.9%. SYBR Green I stained viruses and bacteria are intensely stained and easy to distinguish from other particles with both older and newer generation epifluorescence microscopes. Detritus is generally not stained, unlike when the alternative dye YoPro I is used, so this approach may be suitable for sediments. SYBR Green I stained samples need no desalting or heating, can be fixed with formalin prior to filtration, the optimal staining time is 15 min (resulting in a total preparation time of less than 25 min), and counts can be easily performed at sea immediately after sampling. This method may facilitate incorporation of viral research into most aquatic microbiology laboratories. [TOP OF PAGE]

179. Design of a phage-insensitive lactococcal dairy starter via sequential transfer of naturally occurring conjugative plasmids. O'Sullivan, D., Coffey, A., Fitzgerald, G.F., Hill, C., Ross, R.P. (1998). Appl. Environ. Microbiol. 64:4618-4622. [TOP OF PAGE]

180. Phage viability in organic media: insights into phage stability. Olofsson, L., Ankarloo, J., Nicholls, I.A. (1998). Journal of Molecular Recognition 11:91-93. The stability of the filamentous phages derived from phagemid pG8H6 has been examined in a range of solvents and solvent mixtures. The results show an enhanced capacity to infect E. coli after exposure to various organic solvent-water mixtures. The dependence of stability upon solvent hydrophobicity was demonstrated. Furthermore, conditions have been identified which should allow the application of phage display libraries based upon pG8H6 in organic media. [TOP OF PAGE]

181. Recovery of phages T1 and PP7, and poliovirus from water with a hollow-fiber, 50,000 molecular weight cut-off ultrafilter. Oshima, K., Ommani, A. (1998). Abstracts of the General Meeting of the American Society for Microbiology 98:438-??? [TOP OF PAGE]

182. Virus removal in a membrane separation process. Otaki, M., Yano, K., Ohgaki, S. (1998). Water Science and Technology 37:107-116. Recently, membrane technology has been considered an alternative to conventional water purification. To study the fate of viruses in membrane processes, indigenous coliphages in pilot scale membrane processes located in the eastern part of Tokyo Metropolitan area have been surveyed for 6 months. This plant used river water as its resource and had two microfiltration membrane processes which had different pore sizes (0.2 mum and 0.1 muM) and one ultrafiltration process which had 13,000 nominal molecular weight cut off. To detect indigenous coliphages, E. coli K12 F+(A/lambda) and E. coli C were used as host bacteria. E. coli K12 F+(A/lambda) can detect both DNA and RNA phages and E. coli C can only DNA phage. The resource water contained E. coli K12 phages at 200-1500 PFU/100 mL and the removal ratio of these DNA and RNA phages was lower than that of DNA phage by E. coli C in both MF membrane processes through 6 months. It is thought to be caused by difference of phage size, because DNA phage is bigger than RNA phage in general. The removal ratio of E. coli K12 and E. coli C phages reached 100% in the UF membrane process. According to the comparison of the concentration of phages in solution and eluted from suspended solid in resource and drain, it is thought that most phages concentrated in the drain were absorbed in suspended solids. To make certain of the removal ratio in UF and NF (nanofiltration) processes, high concentrations of coliphage Qbeta and poliomyelitis virus vaccine were fed into these processes. The removal ratio of coliphage Qbeta in UF and NF processes are 10^-8.3 and 10^-6.3 respectively, and the ratio of poliomyelitis virus vaccine in UF and NF are < 10^-6.7 and < 10^-7.3 respectively. [TOP OF PAGE]

183. Bacteriophage: tools toward a cell-targeted delivery. Paillard, F. (1998). Human Gene Therapy 9:2307-2308. [TOP OF PAGE]

184. Genetic dynamics of Salmonella typhi-diversity in clonality. Pang, T. (1998). Trends in Microbiology 6:339-342. "What mechanisms or selective pressures are acting on S. typhi to maintain such plasticity? It is thought that the evolution of virulence in Salmonella spp. is driven by plasmid- or phage-mediated horizontal transfer of genetic elements such as virulence genes and pathogenicity islands (reference). By itself, this mechanisms does not appear to be sufficient for the rapid pace of change and the high degree of genetic variability observed among pathogenic Salmonella spp. Rather, it has been proposed that Salmonella 'mutator' mutants can transiently increase their mutation rate (hypermutable state), which allows genetic variation to occur immediately after infection when the pathogen needs to survive, invade and colonize the human host (reference). This hypothesis is based on the results of recent studies showing that high mutation frequences (>1%) exist among Escerhichia coli and Salmonella, which is related to defects in methyl-directed mismatch repair (MMR) mechanisms (ditto)." p. 340 (emphasis mine; note otherwise that the article does not appear to have an abstract or summary). [TOP OF PAGE]

185. The polyvalent staphylococcal phage í812: its host-range mutants and related phages. Pantucek, R., Rosypalova, A., Doskar, J., Kailerova, J., Ruzickova, V., Borecka, P., Snopkova, S., Horvath, R., Goetz, F., Rosypal, S. (1998). Virology -New York- 246:241-252. [TOP OF PAGE]

186. Starter cultures for Mozzarella cheese. Parente, E., Moschetti, G., Coppola, S. (1998). Annali di Microbiologia ed Enzimologia 48:89-109. The composition of mixed and defined strain starter cultures for the production of Mozzarella cheese is described. The relationship between culture activities and cheese quality, phage related problems, propagation of starter cultures and approaches for culture characterization arc reviewed in detail. [TOP OF PAGE]

187. Phage typing of Lactococcus garvieae (formally Enterococcus seriolicida) a pathogen of cultured yellowtail. Park, K.H., Kato, H., Nakai, T., Muroga, K. (1998). Fisheries science. Tokyo [Fish. Sci. ] 64:62-64. Bacteriophages of Lactococcus garvieae, designated as PLgW and PLgS, were isolated from sea water and sediment samples by an enrichment method. Morphological and genomic features of these phages were in agreement with those of the L. garvieae phage, designated as PLgY, belonging to the family Siphoviridae that was detected in an L. garvieae strain isolated from diseased yellowtail Seriola quinqueradiata in the previous study. One hundred and eleven strains of L. garvieae examined were divided into 14 phage types (A similar to N) by using the phage isolates which were differentiated from each other in the infectivity, with a major phage type (type A) containing 73 strains. One phage type (type N) consisting of 9 bacterial strains was insensitive to any of the phages used. However, there were no apparent correlations between the phage types and the geographical sources of the bacterial strains or between phage types and the antigenic forms (KC- and KG+). [TOP OF PAGE]

188. Biologicheskiye sistemy kontrolya mutagennykh faktorov okruzhayushchey sredy. Pererva, T.P., Aleksandrov, Y., Miryuta, A.Y., Miryuta, N.Y. (1998). Dopovidi Natsional'noyi Akademiyi Nauk Ukrayini. Matematika, Prirodoznavstvo, Tekhnichni Nauki 1998:188-192. Comparative analysis of RNA-containing MS2 phage, DNA-containing lambda phage and Drosophila melanogaster as possible test-objects for study of environmental mutagenic loading is carried out. According to the obtained results, MS2 phage is the most sensible to the combined mutagenic action of studied soil specimens, Drosophila is completely insensible, while lambda phage is located on the intermediate position showing only an insignificant mutagenic response under experimental conditions. [TOP OF PAGE]

189. Biological systems aimed at a control over environmental mutagenic load. Pererva, T.P., Miryuta, N.Y., Miryuta, A.Y., Aleksandrov, Y. (1998). Dopovidi Natsional'noyi Akademiyi Nauk Ukrayiny 188-192. Comparative analysis of RNA-containing MS2 phage, DNA-containing lambda phage and Drosophila melanogaster as possible test-objects for study of environmental mutagenic loading is carried out. According to the obtained results, MS2 phage is the most sensible to the combined mutagenic action of studied soil specimens, Drosophila is completely unsensible, while lambda phage is located on the intermediate position showing only an insignificant mutagenic response under experimental conditions. [TOP OF PAGE]

190. Molecular evolution of a pathogenicity island from enterohemorrhagic Escherichia coli O157:H7. Perna, N.T., Mayhew, G.F., Posfai, G., Elliott, S., Donnenberg, M.S., Kaper, J.B., Blattner, F.R. (1998). Infect. Immun. 66:3810-3817. We report the complete 43,359-bp sequence of the locus of enterocyte effacement (LEE) from EDL933, an enterohemorrhagic Escherichia coli O157:H7 serovar originally isolated from contaminated hamburger implicated in an outbreak of hemorrhagic colitis. The locus was isolated from the EDL933 chromosome with a homologous-recombination-driven targeting vector. Recent completion of the LEE sequence from enteropathogenic E. coli (EPEC) E2348/69 afforded the opportunity for a comparative analysis of the entire pathogenicity island. We have identified a total of 54 open reading frames in the EDL933 LEE. Of these, 13 fall within a putative P4 family prophage designated 933L. The prophage is not present in E2348/69 but is found in a closely related EPEC O55:H7 serovar and other O157:H7 isolates. The remaining 41 genes are shared by the two complete LEEs, and we describe the nature and extent of variation among the two strains for each gene. The rate of divergence is heterogeneous along the locus. Most genes show greater than 95% identity between the two strains, but other genes vary more than expected for clonal divergence among E. coli strains. Several of these highly divergent genes encode proteins that are known to be involved in interactions with the host cell. This pattern suggests recombinational divergence coupled with natural selection and has implications for our understanding of the interaction of both pathogens with their host, for the emergence of O157:H7, and for the evolutionary history of pathogens in general. [TOP OF PAGE]

191. Viral pollution in the environment and in shellfish: Human adenovirus detection by PCR as an index of human viruses. Pina, S., Puig, M., Lucena, F., Jofre, J., Girones, R. (1998). Appl. Environ. Microbiol. 64:3376-3382. A study of the presence of human viruses (adenoviruses, enteroviruses, and hepatitis A viruses (HAVs)) in environmental and shellfish samples was carried out by applying DNA and cDNA amplification techniques by PCR. The detection of human adenoviruses by PCR was also examined as a potential molecular test to monitor viral pollution. The samples studied were urban and slaughterhouse sewage, river water, seawater, and shellfish. Enteroviruses were quantified by PFU in Buffalo green monkey kidney cells and fecal coliforms and phages of Bacteroides fragilis HSP40 were also evaluated in some of the samples. The amplification of viral DNA and cDNA has shown a high prevalence of human viruses that would not be detected by the use of classical techniques, such as the quantification of PFU in cell lines. The results of the analysis of slaughterhouse sewage samples together with the test of farm animal feces indicate that the adenoviruses and the HAVs detected in the environment are mostly of human origin. A significative correlation between the detection of human viruses by PCR and the values of bacteriophages of B. fragilis HSP40 in urban raw sewage was observed. Human adenoviruses were the viruses most frequently detected throughout the year, and all the samples that were positive for enteroviruses or HAVs were also positive for human adenoviruses. The results suggest that the detection of adenoviruses by PCR could be used as an index of the presence of human viruses in the environment where a molecular index is acceptable. [TOP OF PAGE]

192. Abundance, morphology and distribution of planktonic virus-like particles in two high-mountain lakes. Pina, S., Creus, A., Ganzález, N., Gironés, R., Felip, M., Sommaruga, R. (1998). Journal of Plankton Research 20:2413-2421. Direct counts of virus-like particles (VLP) by transmission electron microscopy revealed abundances of up to 3 x 10⁷ ml^-1 in the plankton of two remote high-mountain lakes in the Alps and in the Pyrenees. Most VLP were icosahedric without tail and with diameters between 40 and 90 nm, but also very large ones with diameter of up to 325 nm were observed. VLP outnumbered bacteria by a factor of 4.2 to 42.8 and bacterial cells were infected with large numbers (>50) of viral particles. This study constitutes the first report on aquatic viruses for alpine lakes and it suggests that they may be an important additional source of bacterial mortality in these systems. [TOP OF PAGE]

193. Lysogeny of Oenococcus oeni (syn. Leuconostoc oenos) and study of their induced bacteriophages. Poblet-Icart, M., Bordons, A., Lonvaud-Funel, A. (1998). Current Microbiology 36:365-369. A large number of strains of Oenococcus oeni (formerly Leuconostoc oenos) that had been isolated from wines were checked for lysogeny with mitomycin C as inducer. As a result of this test, 45% of the strains proved to be lysogenic, suggesting that lysogeny is widespread among bacteria isolated from wines during malolactic fermentation. The sensitivity of bacteria to phages was very different, depending on the strain. All the lysogenic strains were resistant to infection by the temperate phage they released. Some phages infected none of the strains. Phages of Oenoc. oeni had a classical morphology, an isometric head, and a long striated tail. With the broadest host strain as an indicator, phages were detected in wines after malolactic fermentation. [TOP OF PAGE]

194. Comparative analysis of the effect of energy process inhibitors on the efficacy of phage infection in staphylococci. Polishko, T.N. (1998). Mikrobiolohichnyi Zhurnal 60:36-42. The study of the effect of KCN, DCCD and CCCP as inhibitors of the energy yielding processes showed that the efficacy of phage infection depended on respiration, protone ATPase, and protone electrochemical potential of hydrogen ions. There was a 49.5-68.0% decrease of the efficacy of phage infection after addition of the above mentioned inhibitors at the period of the contact of cells with bacteriophages at the stage of the phage nucleic acid transfer. The Ambden - Meirhoff - Pamas route inhibitors NaF and CH2ICOOH less affected the efficacy of phage infection. The same effect was observed during addition of Na3AsO4 as the ATP synthesis inhibitor. This efficacy decrease was probably due the inhibition of the processes of the substrate level phosphorylation and the deplete of the intracellular ATP content. [TOP OF PAGE]

195. New method churns out TB mutants. Potera, C. (1998). Science 280, 1350-1351. "…viruses that naturally infect mycobacteria. With few such viruses available commercially, Jacobs turned to a handy source—his own backyard in the Bronx.¶ Bacterial viruses, or phages as they are called, are common soil dwellers, and so Jacobs screened soil from his yard looking for any that infect M. tuberculosis efficienty. He won the 'prokaryotic Lotto,' he says, in 1987 when he found a mutant bacteriophage that infects M. tuberculosis at a frequency seven orders of magnitude higher than its parent." [I know it is difficult to understand what exactly that last sentence is saying, but that is what it says---STA]. [TOP OF PAGE]

196. Biochemical and phylogenetic characterization of the dUTPase from the archaeal virus SIRV. Prangishvili, D., Klenk, H.P., Jakobs, G., Schmiechen, A., Hanselmann, C., Holz, I., Zillig, W. (1998). Journal of Biological Chemistry 273:6024-6029. The derived amino acid sequence from a 474-base pair open reading frame in the genome of the Sulfolobus islandicus rod-shaped virus SIRV shows striking similarity to bacterial dCTP deaminases and to dUTPases from eukaryotes, bacteria, Poxviridae, and Retroviridae. The putative gene was expressed in Escherichia coli, and dUTPase activity of the recombinant enzyme was demonstrated by hydrolysis of dUTP to dUMP. Deamination of dCTP by the enzyme was not detected. Phylogenetic analysis based on amino acid sequences of the characterized enzyme and its homologues showed that the dUTPase-encoding dut genes and the dCTP deaminase-encoding dcd genes constitute a paralogous gene family. This report is the first identification and functional characterization of an archaeal dUTPase and the first phylogeny derived for the dcd-dut gene family. [TOP OF PAGE]

197. Coinfection of a fungal pathogen by two distinct double-stranded RNA viruses. Preisig, O., Wingfield, B.D., Wingfield, M.J. (1998). Virology 252:399-406. Unsegmented double-stranded (ds)RNA viruses belonging to the family Totiviridae persistently infect protozoa and fungi. In this study, two totiviruses were found to coinfect the filamentous fungus Sphaeropsis sapinea, a well known pathogen of pines. Isometric, virus-like particles approximately 35 nm in diameter were isolated from extracts of this fungus. The nucleotide sequences of the genomes of the two S. sapinea RNA viruses named SsRV1 and SsRV2 were established. The linear genomes of 5163 and 5202 bp, respectively, are identically organized with two large, overlapping ORFs. The 5' located ORF1 probably encodes the coat protein, whereas the gene product of ORF2 shows the typical features of RNA-dependent RNA polymerases. The absence of a pseudoknot and a slippery site at the overlapping region between ORF1 and ORF2, as well as the shortness of that region, leads us to suggest that the translation of ORF2 of both viruses is internally initiated. The mode of translation and the genomic organization are similar to those of Helminthosporium victoriae 190S virus (Hv190SV; Huang, S., and Ghabrial, S. A. (1996). Proc. Natl. Acad. Sci. USA 93, 12541-12546). Hv190SV thus appears to be closely related to the SsRVs. Interestingly, based on amino acid sequence homology SsRV1 is more closely related to Hv190SV than to SsRV2. Copyright 1998 Academic Press. [TOP OF PAGE]

198. Complete sequence of the new lactococcal abortive phage resistance gene abiO. Prevots, F., Ritzenthaler, P. (1998). Journal of Dairy Science 81:1483-1485. [TOP OF PAGE]

199. Nucleotide seqeunce and analysis of the new chromosomal abortive infection gene abiN of Lactococcus lactis subsp. cremoris S114. Prevots, F., Tolou, S., Delpech, B., Kaghad, M., Daloyau, M. (1998). FEMS Microbiol. Let. 159:331-336. A 7.275-kb DNA fragment which encodes resistance by abortive infection (Abi⁺) to bacteriophage was cloned from Lactococcus lactis subsp. cremoris S114. The genetic determinant for abortive infection was subcloned from this fragment. This gene was found to confer a reduction in efficiency of plating and plaque size for prolate-headed bacteriophage variant f 53 (group I homology) and for small isometric-headed bacteriophage variant f 59 (group III homology). This new gene, termed abiN, is predicted to encode a polypeptide of 178 amino acid residues with a deduced molecular mass of 20461 Da and an isoelectric point of 4.63. No homology with any previously described genes was found. A probe was used to determine the presence of this gene only in S114 from 31 strains tested. [TOP OF PAGE]

200. Physicochemical characterization of phage adsorption to Lactobacillus helveticus ATCC 15807 cells. Quiberoni, A., Reinheimer, J.A. (1998). Journal of Applied Microbiology 85:762-768. [TOP OF PAGE]

201. Performance of Lactobacillus helveticus spontaneous phage-resistant mutants in hard cheese production. Quiberoni, A., Reinheimer, J., Suarez, J.E. (1998). International Dairy Journal 8:941-949. From the strain Lactobacillus helveticus ATCC 15807, a total of 66 clones were isolated using the lytic phages hv and ATCC 15807-B1. Phenotypic parameters related to their phage resistance capacity (efficiency of plaquing, phage resistance stability, lysogeny and adsorption rates) were determined. The morphological, biochemical (sugar fermentation patterns) and technological (acidifying power, proteolytic activity and slime production) characteristics of the isolates were also studied. Phage resistance stability was a variable property among the isolates but a high level of resistance was exhibited as quantified by the efficiency of plaquing. Furthermore, a total absence of acquired lysogeny was demonstrated. The phage-resistant variants were completely or partially unable to bind phages and did not show differences with Lb. helveticus ATCC 15807 in their biochemical characteristics. However, the technological properties (acidifying powers and proteolytic activities) were heterogeneously distributed among the mutants. The variant RB1-28 (isolated under selective pressure of the phage ATCC 15807-B1) was evaluated for the technological performance in Sardo cheese production in comparison with Lb. helveticus ATCC 15807. There were no significant differences between the two types of cheeses, taking in consideration physicochemical parameters (proteolysis level, dry matter, total and soluble proteins, moisture), microbiological counts or sensory analysis. These phage-resistant variants could be employed in starter strain rotation programs for cheesemaking. [TOP OF PAGE]

202. Genetic (RAPD-PCR) and technological diversities among wild Lactobacillus helveticus strains. Quiberoni, A., Tailliez, P., Quenee, P., Suarez, V., Reinheimer, J. (1998). Journal of Applied Microbiology 85:591-596. Diversity in 25 Lactobacillus helveticus strains isolated from natural whey cultures for Argentinian hard cheese production was studied by means of RAPD-PCR patterns and technological parameters (acidifying and proteolytic activities, salt tolerance, diacetyl, H₂O₂ and slime production, phage sensitivity). In the RAPD diversity study, 10 Lact. helveticus strains from the CNRZ collection were also included. The clustering of RAPD patterns from the Argentinian strains revealed the existence of two Lact. helveticus biotypes. Cluster 1 contained 22 strains (15 wild and seven CNRZ collection strains), Cluster 2 grouped 10 wild strains and Cluster 3 contained only three CNRZ collection strains. RAPD groups could be related to specific cheese-making characteristics (cheese plants). Analysis of technological characteristics in the Argentinian strains showed the occurrence of different natural variants. According to their capacity for growing in milk, they were classified as 'fast', 'intermediate' and 'slow' variants. Among the strains, low salt tolerance and widespread phage resistance were demonstrated. The genetic diversity (RAPD-PCR clustering) did not show any clear relationship with phenotypical diversity. Study of genetic and technological diversity allows a better characterization of wild strains belonging to Lact. helveticus. [TOP OF PAGE]

203. Survival and transfer of faecal indicator organisms of wastewater effluents in receiving lake waters. Rajala, R.L., Heinonen-Tanski, H. (1998). Water Science and Technology 38:191-194. Water of Lake Kallavesi, which receives wastewater effluents, is used for abstraction of drinking water, for swimming and fishing. It is also used directly for washing and drinking water, both for humans and cattle, especially in summer time. These are the reasons for the present study to follow survival and transfer of faecal indicators downstream from the wastewater treatment plant. Samples were collected in winter and summer from the bottom of the lake at deep sites. At some of the sites the vertical distribution of microbes in summer was also studied. Indicators determined were faecal coliforms, enterococci, sulphite-reducing clostridia and coliphages. The farthest point was 35km for bottom samples. All the indicators could be found in sampling sites near to the discharge point with relatively high numbers. At distant sample sites, coliphages or enterococci were the most abundant. In the winter, coliphages were found up to 18km from the discharge point. In summer, indicators survived well. The results suggest that the direct use of lake water could be considered a health risk. [TOP OF PAGE]

204. Coliphages and indicator bacteria in birds around Boston Harbor. Ricca, D.M., Cooney, J.J. (1998). Journal of Industrial Microbiology & Biotechnology 21:28-30. Droppings from feral populations of pigeons, geese and herring gulls from the urban/suburban environment around Boston Harbor, MA, USA contained up to 10⁶ somatic coliphages, 10⁸ enterococcl, 10⁹ thermotolerant coliforms and 10² F-specific coliphages per gram of feces. Somatic collphages, enterococci and thermotolerant coliforms were common in the feces of all three kinds of birds but F-specific collphages were found in droppings from only three of 32 gulls. Thus these sources of bacterial and viral Indicators should be considered when dealing with the ecology of fecal pollution Indicators. Moreover, microbial indicators of fecal or sewage pollution originating from bird droppings may be mistaken for indicators that come from humans. This may cause an overestimate of the hazard from human pathogens in water and confound attempts to locate sources of fecal or sewage pollution. [TOP OF PAGE]

205. Susceptibility of bacteria in estuarine environments to autochthonous bdellovibrios. Rice, T.D., Williams, H.N., Turng, B.F. (1998). Microb. Ecol. 35:256-264. Members of the genus Bdellovibrio exist as obligate predators of other gram-negative bacilli. They are believed to require large numbers of prey bacteria (>10⁴ ml^-1) to survive. Although prey bacteria are essential to the survival of bdellovibrio populations, and to studies of the predator's role in nature, the number of bdellovibrio-susceptible bacteria in environmental samples has not been investigated. This study quantified bacteria that were susceptible to predation by the bdellovibrios. Bacteria recovered from water, sediment, and oyster-shell surface epibiota at various sites in the Chesapeake Bay system were tested for their susceptibility to bdellovibrios collected from homologous sites. The mean number (log₁₀) of susceptible bacterial colonies recovered by culture was 3.33 ml^-1 in water, 4.14 ml^-1 in sediment and 5.76 ml^-1 from oyster shells. Seventy three to 85% of all isolates tested were susceptible to bdellovibrios. Considering the actual number of bacteria in most environments is estimated to be 100 to 1000-fold greater than measured by culturing, the number of bdellovibrio-susceptible bacteria in the three environments sampled is probably sufficient to support the growth of the bdellovibrios. [TOP OF PAGE]

206. Dynamics of the pseudolysogenic response in slowly growing cells of Pseudomonas aeruginosa. Ripp, S., Miller, R.V. (1998). Microbiology (Reading) 144:2225-2232. Pseudolysogeny is an environmental condition in which the starved bacterial cell coexists in an unstable relationship with infecting viral genomes. As nutrients are supplied to the bacterium, the pseudolysogens resolve into either true lysogeny or active production of virions. The direct result of pseudolysogenic relationships is an extension of the effective phage half-lives in natural environments. In this paper a continuous culture model of interactions between bacterial host organisms and bacteriophages leading to pseudolysogeny is presented. The pseudolysogenic state was found to depend on the concentration of nutrients available to the host. As cells became more starved, the frequency of pseudolysogens increased. The dependence on overall nutrient concentration was more dramatic than the variation in the generation time (chemostat turnover time) of the host. Thus, it appears that pseudolysogeny is a legitimate strategy for environmental bacteriophages to adapt to survive periods of starvation of their host organisms. Consideration of pseudolysogeny as a survival strategy is important to the development of any comprehensive model of host-bacteriophage relationships in natural environments. [TOP OF PAGE]

207. The use of luciferase-reporter phage for antibiotic-susceptibility testing of mycobacteria. Riska, P.F., Jacobs, W.J. (1998). Methods in Molecular Biology 101:431-455. [TOP OF PAGE]

208. Yeast positive-stranded virus-like RNA replicons: 20 S and 23 S RNA terminal nucleotide sequences and 3' end secondary structures resemble those of RNA coliphages. Rodriguez-Cousino, N., Solorzano, A., Fujimura, T., Esteban, R. (1998). Journal of Biological Chemistry 273:20363-20371. Saccharomyces cerevisiae strains carry single-stranded RNAs called 20 S RNA and 23 S RNA. These RNAs and their double-stranded counterparts, W and T dsRNAs, have been cloned and sequenced. A few nucleotides at both ends, however, remained unknown. These RNAs do not encode coat proteins but their own RNA-dependent RNA polymerases that share a high degree of conservation to each other. The polymerases are also similar to the replicases of RNA coliphages, such as Qbeta. Here we have determined the nucleotide sequences of W and T dsRNAs at both ends using reverse transcriptase polymerase chain reaction-generated cDNA clones. We confirmed the terminal sequences by primer-extension and RNase protection experiments. Furthermore, these analyses demonstrated that W and T dsRNAs and their single-stranded RNA counterparts (i) are linear molecules, (ii) have identical nucleotide sequences at their ends, and (iii) have no poly(A) tails at their 3' ends. Both 20 S and 23 S IRNAs have GGGGC at the 5' ends and the complementary 5-nucleotides sequence, GCCCC-OH, at their 3' ends. S1 and V1 secondary structure-mapping of the 3' ends of 20 S and 23 S RNAs shows the presence of a stem-loop structure that partially overlaps with the conserved 3' end sequence. Nucleotide sequences and stem-loop structures similar to those described here have been found at the 3' ends of RNA coliphages. These data, together with the similarity of the RNA-dependent RNA polymerases encoded among these RNAs and RNA coliphages, suggest that 20 S and 23 S RNAs are plus-strand single-stranded virus-like RNA replicons in yeast. [TOP OF PAGE]

209. Isolation of three different bacteriophage from mesophilic Aeromonas sp. that use different types of monopolar flagella as their primary receptor. Rubires, X., Merino, S., Aguilar, A., Nogueras, M.M., Tomas, J.M. (1998). FEMS Microbiol. Let. 161:53-57. Bacteriophage PM4, PM5 and PM6 were isolated on different mesophilic Aeromonas strains. These bacteriophage use the flagellum as their primary bacterial receptor since purified flagella from these strains are able to inactivate these bacteriophages, independently, and the phage-resistant mutants are aflagellate and nonmotile. Furthermore, we showed that these bacteriophage may be useful to initiate the serotyping of mesophilic Aeromonas for the H-antigen (flagellum). [TOP OF PAGE]

210. Bacteriophage PRD1 and silica colloid transport and recovery in an iron oxide-coated sand aquifer. Ryan, J.N., Elimelech, M., Ard, R.A., Harvey, R.W., Johnson, P.R. (1998). Environmental Science & Technology 33:63-73. Bacteriophage PRD1 and silica colloids were co-injected into sewage-contaminated and uncontaminated zones of an iron oxide-coated sand aquifer on Cape Cod, MA, and their transport was monitored over distances up to 6 m in three arrays. After deposition, the attached PRD1 and silica colloids were mobilized by three different chemical perturbations (elevated pH, anionic surfactant and reductant). PRD1 and silica colloids experienced less attenuation in the contaminated zone where adsorbed organic matter and phosphate may be hindering attachment of PRD1 and silica colloids to the iron oxide coatings. The PRD1 collision efficiencies agree well with collision efficiencies predicted by assuming favorable PRD1 deposition on iron oxide coatings for which the surface area coverage was measured by microprobe analysis of sediment thin sections. zeta potentials of the PRD1, silica colloids, and aquifer grains corroborated the transport results, indicating that electrostatic forces dominated the attachment of PRD1 and silica colloids. Elevated pH was the chemical perturbation most effective at mobilizing the attached PRD1 and silica colloids. Elevated surfactant concentration mobilized the attached PRD1 and silica colloids more effectively in the contaminated zone than in the uncontaminated zone. [TOP OF PAGE]

211. Seasonal abundance in Skagerrak-Kattegat coastal waters and host specificity of viruses infecting the marine photosynthetic flagellate Micromonas pusilla. Sahlsten, E. (1998). Aquat. Microb. Ecol. 16:103-108. Seawater sampled in the Skagerrak and Kattegat coastal waters during the period October 1995 to September 1996 were screened for the occurrence of viruses lytic to marine microalgae. Viruses lytic to the photosynthetic marine picoflagellate Micromonas pusilla (Butcher) Manton & Parke (Prasinophyceae) were detected in all seawater samples screened. Evidence for viral lysis of any other of the 11 algal species tested was not obtained. Several viruses infecting different strains of M. pusilla were isolated. Ten isolated viruses which were tested for host specificity were found to be species specific to M. pusilla and even strain specific to 1-3 of the 6 strains of M pusilla used in the experiment. In the Skagerrak and Kattegat the seasonal abundance of viruses infectious to a M. pusilla strain isolated from the Oslofjord, Norway, was at least 1 order of magnitude higher (average 2.5 x 10⁵ l^-1) than viruses infecting 2 M. pusilla strains isolated from Gull of Maine, USA (average 2.2 x 10⁴ and 4.6 x 10³ l^-1 respectively). [TOP OF PAGE]

212. Vertical distribution of virus-like particles (VLP) and viruses infecting Micromonas pusilla during late summer in the southeastern Skagerrak. Sahlsten, E., Karlson, B. (1998). J. Plankton Res. 20:2207-2212. Vertical profiles were made at one offshore station and one coastal station, on 4-5 September 1996, in the south-eastern Skagerrak. The surface water of the two stations differed significantly with respect to both temperature and salinity, as the outer station (A) was situated in high-saline water originating from the North Sea, while the low-saline surface water at the inner station (B) was influenced by the Baltic current. Virus-like particle (VLP) abundance was 5 x 10⁹-25 x 10⁹ l(-1) in the 0-50 m water column. Maximal VLP values were found in the surface water, although a lower number was detected in the low-saline surface water (0 m depth) at station B. Viruses infective to Micromonas pusilla were estimated to similar to 0.01% of the VLP number. The ambient concentrations of dissolved inorganic nutrients were typical for a stratified summer situation, i.e. generally low in the surface waters, although a raised ammonium concentration was associated with the sharp halocline at 5 m depth at station B, and all nutrient levels were increasing below 30 m depth. [TOP OF PAGE]

213. Characterisation of 16 Campylobacter jejuni and C. coli typing bacteriophages. Sails, A.D., Wareing, D.R., Bolton, F.J., Fox, A.J., Curry, A. (1998). J. Med. Microbiol. 47:123-128. Taxonomic classification of bacteriophages specific for Campylobacter jejuni and C. coli has not been reported previously. A set of 16 virulent phages, distinguishable by their lytic spectra, has been used extensively for epidemiological typing of C. jejuni and C. coli at Preston Public Health Laboratory. These phages were investigated by electron microscopy, pulsed-field gel electrophoresis and restriction endonuclease analysis. All phages had icosahedral heads and long contractile tails. Accordingly, they were classified as members of the Myoviridae family. These phages could be subdivided into three groups according to genome size and head diameter: group I, two phages with head diameters of 140.6 and 143.8 nm and genome sizes of 320 kb; group II, five phages with average head diameters of 99 nm and average genome sizes of 184 kb; and group III, nine phages with average head sizes of 100 nm and average genome sizes of 138 kb. Phages NCTC12676 and NCTC12677 of group I had unusually large genomes of c. 320 kb which are two of the largest phage genomes to be described. Restriction endonuclease analysis demonstrated that DNA from the 16 phages was refractory to digestion by a number of restriction enzymes. [TOP OF PAGE]

214. A comparative study on the frequency of prophages among natural isolates of Salmonella and Escherichia coli with emphasis on generalized transducers. Schicklmaier, P., Moser, E., Wieland, T., Rabsch, W., Schmieger, H. (1998). Antonie van Leeuwenhoek 73:49-54. Several collections of natural isolates of the genus Salmonella and of the species Escherichia coli were studied for the release of viable temperate phages. The results indicated that functional prophage genomes may be a common constituent of all bacterial genomes of the investigated strains. About 99% of the Salmonella phages are capable of generalized transduction of chromosomal host markers and plasmids. The ratio of transducing E. coli phages is significantly lower. [TOP OF PAGE]

215. Reduction of FRNA-bacteriophages and faecal indicator bacteria by dune infiltration and estimation of sticking efficiencies. Schijven, J.F., Hoogenboezem, W., Nobel, P.J., Medema, G.J., Stakelbeek, A. (1998). Water Science and Technology 38:127-131. A field study was performed to investigate reduction by dune infiltration and to estimate sticking efficiencies of F-specific RNA bacteriophages, total and thermotolerant coliforms, faecal streptococci and spores of sulphite-reducing clostridia. Reduction was considered as a beta-binomially distributed process and a Monte Carlo simulation wag applied for estimating sticking efficiencies. Reduction of F-specific RNA bacteriophages within the first 2m was 3.8 log10 and the sticking efficiency was about 0.002. The faecal indicator bacteria were removed only 0.9 log10 within 2m and sticking efficiency was 0.007. Concentrations of spores of sulphite reducing clostridia were reduced 1.9 log10 and their sticking efficiency was about 0.009. [TOP OF PAGE]

216. A new bacteriophage typing scheme for Proteus mirabilis and Proteus vulgaris strains: 3. Analysis of lytic properties. Sekaninova, G., Rychlik, I., Kolarova, M., Pillich, J., Semenka, J., Zajicova, V. (1998). Folia Microbiologica 43:136-140. The lytic properties of 21 bacteriophages constituting a new typing set for Proteus were examined in 507 Proteus mirabilis and 29 P. vulgaris strains isolated from patients and healthy subjects. Comparison of their morphological, serological, genetic and lytic properties showed that, in the Myoviridae and Podoviridae families, some phages were so closely related that the presence of all of them in the set was redundant. Analysis of the lytic properties revealed that some of the bacteriophages were not active enough to facilitate the differentiation of Proteus strains. The size of the final typing set was reduced from 21 to 12 phages but it was suggested that, in order to improve the differentiation capacity of the set, new phages should be included. [TOP OF PAGE]

217. Parvovirus B19-induced anemia as the presenting manifestation of X-linked hyper-IgM syndrome. Seyama, K., Kobayashi, R., Hasle, H., Apter, A.J., Rutledge, J.C., Rosen, D., Ochs, H.D. (1998). Journal of Infectious Disease 178:318-324. Parvovirus B19 (B19) can cause chronic anemia due to persistent infection in immunocompromised hosts who cannot produce neutralizing antibody necessary for clearing B19. Three patients with X-linked hyper-IgM syndrome (XHIM), who were all asymptomatic until they developed B19-induced chronic anemia at the ages of 8, 14, and 17 years, respectively, were found to have mutations of the CD40L gene, including a missense mutation (T254M), a nonsense mutation resulting in a new initiation codon and loss of the intracellular domain (R11X), and a splice site mutation (nt 309+2t-->a). Antibody responses to the T cell-dependent antigen, bacteriophage fX174, were impaired, but neutralizing antibody titers were higher than in XHIM patients with classic phenotype. All 3 patients responded to intravenous immune globulin (IVIG) treatment. Certain mutations of the CD40L gene result in a mild XHIM phenotype that may become apparent following B19 infection in patients not on IVIG therapy and therefore not protected from B19 infection. [TOP OF PAGE]

218. Reduction of Norwalk virus, poliovirus 1 and coliphage MS2 by monochloramine disinfection of water. Shin, G.A., Sobsey, M.D. (1998). Water Science and Technology 38:151-154. The reduction of Norwalk virus (NV) by a 2 mg/L dose of pre-formed monochloramine was determined at pH 8 and 5degreeC in bench-scale, batch disinfection experiments using quantitative RT-PCR for NV assays. Two other enteric viruses, poliovirus 1 (PV1) and coliphage MS2, were included for comparison and assayed by infectivity as well as RT-PCR. After 3h, reductions of PV1 and MS2 by infectivity assays were about 1 log10 but there were no reductions of these viruses by RT-PCR assays. Hence, RT-PCR underestimated virus inactivation by monochloramine. However, NV reduction by monochloramine was about 1 log10 by RT-PCR assay, suggesting that it is more susceptible to monochloramine than the other two viruses tested. Based on RT-PCR titre reduction, the CT99 value for NV was about 775 mg-min/L. If the reduction of NV infectivity by monochloramine is ever greater than the reduction of RT-PCR signals, the CT99 value would be smaller. However, the results of this study indicate that NV and the other enteric viruses tested are not rapidly and extensively reduced by disinfection with preformed monochloramine. [TOP OF PAGE]

219. Phenotypic mixing of pyocin R2 and bacteriophage PS17 in Pseudomonas aeruginosa. Shinomiya, T. (1998). J. Virol. 49:310-??? [TOP OF PAGE]

220. Bacterioplankton dynamics in Lake Constance (Bodensee): Substrate utilization, growth control, and long-term trends. Simon, M., Bunte, C., Schulz, M., Weiss, M., Wuensch, C. (1998). In Baeuerle, E. and Gaedke, U. (eds.), Archiv fuer Hydrobiologie. Spec. issue: Ergebnisse der Limnologie. Schweizerbart'sche Verlagsbuchhandlung, Stuttgart (FRG). The authors studied the dynamics of bacterioplankton growth and the factors controlling it in Lake Constance between 1982 and 1997, but mainly during the last 8 years. In the course of this time, the lake experienced a significant oligotrophication due to an efficient decrease in the phosphorus load. The large changes in nutrient load and concomitant qualitative and quantitative changes in the phytoplankton community made it a particularly interesting time to study bacterial growth dynamics. Both bacterial production (BP) and bacterial numbers (BN) showed persistent annual patterns throughout the period. In most years, highest rates of BP and BN occurred towards the end of the phytoplankton spring bloom. During the clear-water phase, BP and BN varied depending on the grazing pressure by daphnids and decreased towards its end. During summer, BP and BN increased again and to varying extents until the autumnal decline. In 1995 and 1997, highest rates occurred in summer (August, September). In particular, BN remained lower in summer than during the previous part of the season. During the spring bloom, BP was closely correlated either to the biomass of ciliates or of daphnids, but only weakly to chlorophyll, indicating that grazing and thus release of dissolved organic matter by these two herbivores was the most important factor in bottom-up control of bacterial growth at this time. Dissolved free and combined amino acids as well as dissolved free and combined carbohydrates constituted the pool of labile dissolved organic matter to a great extent and were always the major bacterial substrates utilized. At maxima of BP amino acids were preferred whereas carbohydrates were utilized to a greater extent at high and declining bacterial numbers. The bacterial growth efficiency changed seasonally, but in general ranged between 20 and 40 %. During most of the growing season, bacterioplankton growth was co-limited by phosphorus and organic carbon whereas during winter only organic carbon was limiting. Temperature has relatively little direct impact on bacterioplankton growth in the epilimnion because the bacterial assemblages adapted fairly well to the changing ambient temperatures. In the deeper water, temperature directly controlled BP during most of the year. The major loss factors of bacterioplankton comprised phage-induced mortality and grazing by heterotrophic nanoflagellates (HNF), ciliates, and daphnids. On average, phages accounted for 1-24 % of total mortality whereas grazing by HNF for 52-68 %, by ciliates for 14-19 %, and by daphnids for 9-12 %. During the clear-water phase, however, grazing by daphnids dominated by more than 50 %. During oligotrophication, the annual ratio of BP/primary production (PP) integrated from 0 to 20 m varied between 0.09 and 0.29, but without a clear-cut trend. In 1995 and 1996, bacterial growth rates were enhanced and the biomasses of daphnids and autotrophic picoplankton reduced as compared to the previous years. This suggests that grazing control of BP by HNF became more important than before in this late stage of oligotrophication. [TOP OF PAGE]

221. The origin and evolution of viruses (a review). Sinkovics, J., Horvath, J., Horak, A. (1998). Acta Microbiol. Immunol. Hungarica 45:349-390. Viroids and prions might have existed early at the border of inanimate and living worlds. Most extant viruses can be characterized as derivatives of ancestors originating from episomal elements of prokaryotes (DNA phages) and later from eukaryotes. Retroviruses very likely originated from cellular retrotransposons. Retrograde evolution of some large viruses from obligatory intracellular bacteria is possible but the ontogenesis of extant bacteria does not include a viral form of existence (the filterable L forms are not viruses) and well-defined viruses do not regenerate back into vegetative bacterial forms. Biologists experimenting with the evolution of prokaryotic and eukaryotic ancient cells cannot ignore the earliest appearance of viruses within or outside the living matter. Viruses participated in and gave direction to the evolution and natural selection by coexisting with uni- and multicellular organisms for billions of years. The coevolution of viruses and their host cells is characterized by incessant attacks and counterattacks through gene rearrangements and mutations (induced in the virus by an immunological counterattack of the host or by transgression of species barriers by the virus) and recombinations. Recombinations occurred between viral and viral or viral and host genes. Acts of "molecular piracy" as practiced by ancient viruses endowed the virus with the expression of several host genes for the advantage of the virus in its replicative cycle and host-to-host spread. Probably the first immortalized and malignantly transformed cells were induced by viruses as viruses evolved anti-apoptotic measures. While infected cells resort to apoptotic death before the assembly of a new viral progeny, prominent are the anti-apoptotic measures viruses evolved in order to assure the completion of their full replicative cycle. Further, viruses may escape neutralization by host antibodies and may survive a counterattack by the host's T cells directed at virally infected cells of its own. Viruses may induce a form of tolerance and coexist with their host without inducing disease. Persistent and apparently or deceivingly apathogenic or even attenuated viral "quasi-species" populations may contain individual particles that regain virulence due to recombinations and/or gene rearrangements, especially when transgressing species barriers. Xenotropic viruses of animals may replicate in human cells and vice versa confounding experiments with xenotransplants or with use of veterinary viral vaccines for the treatment of human diseases. [TOP OF PAGE]

222. Distinguishing human from animal faecal contamination in water: A review. Sinton, L.W., Finlay, R.K., Hannah, D.J. (1998). New Zealand Journal of Marine and Freshwater Research 32:323-348. Management of faecal contamination of water would be improved if sources could be accurately identified through water analysis. Human faeces are generally perceived as constituting a greater human health risk than animal faeces, but reliable epidemiological evidence is lacking. United States waterborne disease data suggest that human-specific enteric viruses account for over half the documented outbreaks. However, in New Zealand, where there is a high grazing animal:human ratio (increasing the relative importance of water-transmissible zoonoses), it seems prudent to assume that human and animal faecal pollution both constitute a risk to human health. Irrespective of the relative risks, the ability to identify sources would assist in overall management of microbial water quality. Faecal streptococci do not appear to provide reliable faecal source identification. Human and animal sources, respectively, may be distinguishable by two tests on Bifidobacterium spp.-growth at 45 degrees C in trypticase phytone yeast broth and sorbitol fermentation. Different species of Bacteroides tend to be present in humans and animals, but poor survival in water is a problem. Phages of the Bacteroides fragilis strain HSP40 appear to be human specific, but low counts in effluent in some countries, including New Zealand, may limit their usefulness. Different F-RNA phage subgroups appear to be associated with human and animal faecal sources. The actinomycete Rhodococcus coprophilus has potential as a grazing animal indicator but it is persistent, and existing culturing techniques are time consuming. The development of DNA-based techniques, such as polymerase chain reaction (PCR), may assist in the assay of some microbial faecal source indicators. Various faecal sterol isomers offer the possibility of distinguishing between human and animal sources, and even between different animals. Washing powder constituents such as fluorescent whitening agents, sodium tripolyphosphate and linear alkyl benzenes, offer useful human source identifiers. It is unlikely that any single determinant will be useful in all situations, but statistical analysis of appropriate "baskets" of microbial and chemical determinants offers the possibility of identifying and apportioning human and animal faecal inputs to natural waters. [TOP OF PAGE]

223. Isolation of phages and phage typing of Bacillus cereus. Smimizu, M., Inoue, M., Miyazawa, W., Itoh, T. (1998). Japanese Journal of Food Microbiology 15:147-152. A set of phages for typing Bacillus cereus was developed. 96 phages were isolated from 85 soil samples using B. cereus (of 36 H-serovars) as indicator strains. 11 phages were selected based on their stability and host range, and could be classified into 5 groups. 5 phages (_a, _b, _c, _d and _e) were used as a typing phage set. At routine test dilution (RTD) and 100 x RTD, 36 B. cereus strains were typed into 17 phage patterns (83.3% typeable) and 11 phage patterns (100% typeable), 25 isolates from powdered fish meal samples were typed into 9 phage patterns (48% typeable) and 9 phage patterns (100% typeable), and 100 isolates from soil samples were typed into 24 phage patterns (79% typeable) and 14 phage patterns (100% typeable), respectively. [From En summ.]. [TOP OF PAGE]

224. RT-PCR amplification detects inactivated viruses in water and wastewater. Sobsey, M.D., Battigelli, D.A., Shin, G.A., Newland, S. (1998). Water Science and Technology 38:91-94. Nucleic acid (NA) amplification techniques are useful to detect viruses in water and other environmental samples because they are highly sensitive, specific and can detect fastidious enteric viruses that do not grow well or not at all in cell cultures. However, RT-PCR was found to detect inactivated viruses. In terms of risks to public health this constitutes a false positive result, as inactivated viruses are no longer infectious. When poliovirus type 1 and coliphage MS2 were studied for (a) persistence in water and sewage and (b) inactivation in water by free chlorine, chlorine dioxide and UV radiation, RT-PCR assays underestimated virus inactivation. The use of multiple RT-PCR amplification sites, larger RT-PCR genomic targets and immunocapture RT-PCR sometimes reduced, but did not eliminate, the discrepancy between loss of infectivity and loss of RT-PCR titre. Virus presence based on RT-PCR detection must be interpreted with caution when predicting human health risks. [TOP OF PAGE]

225. Time dose reciprocity in UV disinfection of water. SOMMER, R., Haider, T., Cabaja., Pribil, W., Lhotsky, M. (1998). Water Science and Technology 38:145-150. The microbicidal effect of UV light depends on the dose in both, disinfection processes and natural inactivation by the sunlight in surface water. Deviations of the time dose reciprocity are well known from chemical water disinfection whereas no data are available about this effect in UV inactivation in water. In a previous study we found that the UV inactivation behaviour of yeast strains does not follow the time dose reciprocity, insofar that longer exposure led to higher reduction of cultivable cells. In contrast, an earlier study about E. coli B/r claimed a higher inactivation with single exposure compared with fractionated UV irradiation. To investigate this question we selected water-relevant microorganisms and studied their UV inactivation behaviour (253.7nm) by means of a specially designed UV irradiation apparatus (a) under standard irradiation conditions (2W/m2) and (b) with three levels of UV dose rate (2, 0.2 and 0.02W/m2). The test organisms were (i) three E. coli strains (ATCC 25922, ATCC 11229 and an isolate from sewage) representing the routinely used faecal indicator, (ii) three bacterial viruses (MS2, variant phiX174 and B40-8) proposed as indicators for viral contamination in water and (iii) spores of Bacillus subtilis because of their use as a biodosimeter in prototype testing of commercial UV plants for drinking water disinfection. We found, under standard inactivation conditions, that the E. coli strains and phage variant phiX174 are most UV susceptible, followed by B40-8 and finally MS2 and bacterial spores. The dose protraction experiments revealed for the E. coli strains a higher inactivation with high dose rates compared to low dose rates at the same UV doses (difference of about 1 log10 at 80-100J/m2). The other test organisms did not deviate from the time dose reciprocity in the proven range of dose. [TOP OF PAGE]

226. Phage therapy. Soothill, J.S. (1998). Journal Of Pharmacy And Pharmacology 50:36-36. [TOP OF PAGE]

227. The specific and sensitive detection of bacterial pathogens within 4 h using bacteriophage amplification. Stewart, G.S., Jassim, S.A., Denyer, S.P., Newby, P., Linley, K., Dhir, V.K. (1998). Journal of Applied Microbiology 84:777-783. This paper describes a novel approach, termed the 'phage amplification assay', for the rapid detection and identification of specific bacteria. The technique is based on the phage lytic cycle with plaque formation as the assay end-point. It is highly sensitive, quantitative and gives results typically within 4 h. The assay comprises four main stages: (1) phage infection of target bacterium; (2) destruction of exogenous phage; (3) amplification of phage within infected host and (4) plaque formation from infected host with the aid of helper bacteria. A key component of this assay is a potent virucidal agent derived from natural plant extracts, pomegranate rind extract (PRE). In combination with ferrous sulphate PRE can bring about an 11 log-cycle reduction in phage titre within 3 min. This is achieved without any injury to the infected target bacteria. Subsequently, any resulting plaques are derived only from infected target organisms. Data are presented for a range of bacterial hosts including Pseudomonas aeruginosa, Salmonella typhimurium and Staphylococcus aureus. The detection limit for Ps. aeruginosa was 40 bacteria ml^-1 in a time of 4 h and 600 bacteria m^-1 for Salm. typhimurium. Application of the principles of this technology to other bacterial genera is discussed. [TOP OF PAGE]

228. [The effect of low-frequency electromagnetic fields on living organisms]. Strasak, L., Vetterl, V., Smarda, J. (1998). Sbornik Lekarsky 99:455-464. This report studies effect of alternating low-frequency electromagnetic fields (Bm = 5-21.5 mT, f = 50 Hz, duration of exposure t = 0-24 min) on viability of bacteria Escherichia coli. We have shown that the growth of bacteria is impaired the electromagnetic field. Their ability to form colonies on a solid medium decreases in dependence on magnitude of magnetic field and on duration of exposure. The growth curve is influenced by the electromagnetic field as well. Effects of electromagnetic fields are independent of biological age in first four hours of their growth. We have found no morphological changes in bacterial systems in electromagnetic field by optical microscope. Viability of bacteria is bigger in a liquid medium and less in a solid medium. Bacteriophage BF 23 attach less to bacteria influenced by electromagnetic field. And finally, magnetic field did not make induction of production of bacteriophage. This effect indicates, that magnetic field did not damage DNA of exposed bacteria. [TOP OF PAGE]

229. Construction of bacteriophage resistant strains of Streptococcus thermophilus by pGh9::ISS1 insertional mutagenesis. Sturino, J.M., Steele, J.L. (1998). Journal of Dairy Science 81:7 [TOP OF PAGE]

230. Lack of surface receptors not restriction-modification system determines F4 phage resistance in Streptococcus bovis II/1. Styriak, I., Pristas, P., Javorsky, P. (1998). Folia Microbiologica 43:35-38. The resistance of Streptococcus bovis strain II/1, the producer of SbvI restriction endonuclease, to F4 phage infection was demonstrated by the double-agar-layer method. Despite the presence of restriction endonuclease SbvI which can cleave F4 phage DNA to numerous fragments in vitro, the evidence that adsorption inhibition is the most important defense mechanism in phage resistance of S. bovis II/1 strain was obtained by adhesion experiments in vivo. Electron microscopy of phage-host mixtures showed many phage particles on the bacterial surface of phage-sensitive S. bovis 47/3 control strain in comparison with no phage particles seen on S. bovis II/1 (phage-resistant) strain surface. [TOP OF PAGE]

231. Detection, quantification and morphological characterization of Vibrio cholerae indicator bacteriophages [Spanish]. Talledo, M.A., Gutiérrez, S., Merino, F., Rojas, N. (1998). Rev. Peru. Biol. 5:90-97. [TOP OF PAGE]

232. Temperate viruses and lysogeny in Lake Superior bacterioplankton. Tapper, M.A., Hicks, R.E. (1998). Limnol. Oceanogr. 43:95-103. The morphology and abundance of free viruses were measured in spring, summer, and fall at one site in Lake Superior. Free viral head sizes ranged from 10 to 70 nm and tail length ranged from 10 to 110 nm. The vast majority (98%) of free viral head sizes were <60 nm, smaller than reported in most freshwater habitats. Most of these free viruses (70%) had polyhedral heads and tails, indicative of bacteriophage. Free viral abundance only ranged from 0.1 to 9 X 10⁶ viruses ml^-1 in the surface microlayer (top 20 mum) and subsurface water (20m) in Lake Superior, but viruses were 2^-15 times more abundant in the surface microlayer. This difference may be due to the enrichment of bacterial hosts, higher levels of UV light that induce temperate phage, or differences in viral burst sizes in the surface microlayer relative to subsurface water. Bacterioplankton were always more abundant than free viruses in both the surface microlayer and subsurface water, which resulted in some of the lowest virus-to-bacterium ratios reported for marine or freshwater environments. Temperate viruses from both habitats responded equally to mitomycin-C and UV light treatments used to induce prophage into lytic cycles. An estimated 0.1-7.4% of the bacterioplankton from this site in Lake Superior contained temperate prophage depending on viral burst sizes that were assumed. Three times more bacteria in the surface microlayer may contain temperate viruses compared to bacterioplankton in subsurface waters. In the western arm of Lake Superior, bacterioplankton infected by temperate phage may be more important for the survival of bacteriophage populations than as future carbon sources for new microbial production. [TOP OF PAGE]

233. Morphology and abundance of free and temperate viruses in Lake Superior. Tapper, M.A., Hicks, R.E. (1998). Limnol. Oceanogr. 43:95-103. The morphology and abundance of free viruses were measured in spring, summer, and fall at one site in Lake Superior. Free viral head sizes ranged from 10 to 70 nn and tail length ranged from 10 to 110 nm. The vast majority (98%) of free viral head sizes were less than or equal to 60 nm, smaller than reported in most freshwater habitats. Most of these free viruses (70%) had polyhedral heads and tails, indicative of bacteriophage. Free viral abundance only ranged from 0.1 to 9 x 10(6) viruses ml(-1) in the surface microlayer (top 20 mu m) and subsurface water (20 m) in Lake Superior, but viruses were 2-15 times more abundant in the surface microlayer. This difference may be due to the enrichment of bacterial hosts, higher levels of UV light that induce temperate phage, or differences in viral burst sizes in the surface microlayer relative to subsurface water. Bacterioplankton were always more abundant than free viruses in both the surface microlayer and subsurface water, which resulted in some of the lowest virus-to-bacterium ratios reported for marine or freshwater environments. Temperate viruses from both habitats responded equally to mitomycin-C and UV light treatments used to induce prophage into lytic cycles. An estimated 0.1-7.4% of the bacterioplankton from this site in Lake Superior contained temperate prophage depending on viral burst sizes that were assumed. Three times more bacteria in the surface microlayer may contain temperate viruses compared to bacterioplankton in subsurface waters. In the western arm of Lake Superior, bacterioplankton infected by temperate phage may be more important for the survival of bacteriophage populations than as future carbon sources for new microbial production. [TOP OF PAGE]

234. Genome plasticity in the distal tail fiber locus of the T-even bacteriophage: recombination between conserved motifs swaps adhesin specificity. Tétart, F., Desplats, C., Krisch, H.M. (1998). J. Mol. Biol. 282:543-556. The adsorption specificity of the T-even phages is determined by the protein sequence near the tip of the long tail fibers. These adhesin sequences are highly variable in both their sequence and specificity for bacterial receptors. The tail fiber adhesin domains are located in different genes in closely related phages of the T-even type. In phage T4, the adhesin sequence is encoded by the C-terminal domain of the large tail fiber gene (gene 37), but in T2, the adhesin is a separate gene product (gene 38) that binds to the tip of T2 tail fibers. Analysis of phage T6 and Ac3 sequences reveals additional variant forms of this locus. The tail fiber host specificity determinants can be exchanged, although the different loci have only limited homology. Chimeric fibers can be created by crossovers either between small homologies within the structural part of the fiber gene or in conserved motifs of the adhesin domain. For example, the T2 adhesin determinants are flanked by G-rich DNA motifs and exchanges involving these sequences can replace the specificity determinants. These features of the distal tail fiber loci genetically link their different forms and can mediate acquisition of diverse host range determinants, including those that allow it to cross species boundaries and infect taxonomically distant hosts. [TOP OF PAGE]

235. Polymorphism of the T-even bacteriophage distal tail fiber locus: Recombination between conserved motifs swaps adhesin specificities. Tétart, F., Desplats, C., Krisch, H.M. (1998). Journal of Molecular Biology . The adsorption specificity of the T-even phages is determined by the protein sequence near the tip of the long tail fibers. These adhesin sequences are highly variable in both their sequence and specificity for bacterial receptors. The tail fiber adhesin domains are located in different genes in... [TOP OF PAGE]

236. A theoretical approach to structuring mechanisms in the pelagic food web. Thingstad, T.F. (1998). Hydrobiolica 363:59-72. In the literature there is a commonly used idealized concept of the food web structure in the pelagic photic zone food web, based to a large extent on size dependent relationships. An outline is here given of how the elementary size-related physical laws of diffusion and sinking, combined with the assumption of predators being size selective in their choice of prey, give a theoretical foundation for this type of structure. It is shown how such a theoretical fundament makes it possible to relate a broad specter of phenomena within one generic and consistent framework. Phenomena such as Hutchinson's and Goldman's paradoxes, the influence of nutrients and water column stability on the balance between microbial and classical food webs, bacterial carbon consumption, new production and export of DOC and POC to the aphotic zone, eutrophication and diversity, can all be approached from this perspective. By including host-specific viruses, this approach gives a hierarchical structure to the control of diversity with nutrient content controlling the maximum size of the photic zone community, size selectivity of predators regulating how the nutrient is distributed between size-groups of osmotrophic and phagotrophic organisms, and viral host specificity regulating how the nutrients within a size group is distributed between host groups. I also briefly discuss how some biological strategies may be successful by not conforming to the normal rules of such a framework. Analyzing the behavior of these idealized systems is thus claimed to facilitate our understanding of the behavior of complex natural food webs. [TOP OF PAGE]

237. Role of the air-water-solid interface in bacteriophage sorption experiments. Thompson, S.S., Flury, M., Yates, M.V., Jury, W.A. (1998). Appl. Environ. Microbiol. 64:304-309. Batch sorption experiments were carried out with the bacteriophages MS2 and vf-X174. Two types of reactor vessels, polypropylene and glass, were used. Consistently lower concentrations of MS2 were found in the liquid phase in the absence of soil (control blanks) than in the presence of soil after mixing. High levels of MS2 inactivation ( apprx 99.9%) were observed in control tubes made of polypropylene (PP), with comparatively little loss of virus seen in PP tubes when soil was present. Minimal inactivation of MS2 was observed when the air-water interface was completely eliminated from PP control blanks during mixing. All batch experiments performed with reactor tubes made of glass demonstrated no substantial inactivation of MS2. In similar experiments, bacteriophage vf-X174 did not undergo inactivation in either PP or glass control blanks, implying that this virus is not affected by the same factors which led to inactivation of MS2 in the PP control tubes. When possible, phage adsorption to soil was calculated by the Freundlich isotherm. Our data suggest that forces associated with the air-water-solid interface (where the solid is a hydrophobic surface) are responsible for inactivation of MS2 in the PP control tubes. The influence of air-water interfacial forces should be carefully considered when batch sorption experiments are conducted with certain viruses. [TOP OF PAGE]

238. Is the major capsid protein of iridoviruses a suitable target for the study of viral evolution? Tidona, C.A., Schnitzler, P., Kehm, R., Darai, G. (1998). Virus Genes 16:59-66. Iridoviruses are large cytoplasmic DNA viruses that are specific for different insect or vertebrate hosts. The major structural component of the non-enveloped icosahedral virus particles is the major capsid protein (MCP) which appears to be highly conserved among members of the family Iridoviridae, Phycodnaviridae, and African swine fever virus. The amino acid sequences of the known MCPs were used in comparative analyses to elucidate the phylogenic relationships between different cytoplasmic DNA viruses including three insect iridoviruses (Tipula iridescent virus, Simulium iridescent virus, Chilo iridescent virus), seven vertebrate iridoviruses isolated either from fish (lymphocystis disease virus, rainbow trout virus, European catfish virus, doctor fish virus), amphibians (frog virus 3), or reptiles (turtle virus 3, turtle virus 5), one member of the family Phycodnaviridae (Paramecium bursaria Chlorella virus type 1), and African swine fever virus. These analyses revealed that the amino acid sequence of the MCP is a suitable target for the study of viral evolution since it contains highly conserved domains, but is sufficiently diverse to distinguish closely related iridovirus isolates. Furthermore, the results suggest that a substantial revision of the taxonomy of iridoviruses based on molecular phylogeny is required. [TOP OF PAGE]

239. Biological properties and classification of Erwinia carotovora bacteriocins. Tovkach, F.I. (1998). Mikrobiologiya 67:767-774. Study of 52 phytopathogenic strains of Erwinia carotovora showed that all of them could produce both colicin-like and macromolecular phage-tail-like bacteriocins. Colicin-like carotovoricins proved to lyse phytopathogenic agrobacteria, pseudomonads, and E. chrysanthemi, as well as the representatives of E. herbicola and Klebsiella sp. Macromolecular carotovoricins (MCTV) primarily lysed E. carotovora and Escherichia coli strains. A classification of MCTV was elaborated. [TOP OF PAGE]

240. Modeling the oddities of biology. Trivedi, B. (1998). Nature Biotechnology 16:1316-1317. [TOP OF PAGE]

241. Sex and the evolution of intrahost competition in RNA virus f6. Turner, P.E., Chao, L. (1998). Genetics 150:523-532. Sex allows beneficial mutations that occur in separate lineages to be fixed in the same genome. For this reason, the Fisher-Muller model predicts that adaptation to the environment is more rapid in a large sexual population than in an equally large asexual population. Sexual reproduction occurs in populations of the RNA virus phi6 when multiple bacteriophages coinfect the same host cell. Here, we tested the model's predictions by determining whether sex favors more rapid adaptation of phi6 to a bacterial host, Pseudomonas phaseolicola. Replicate populations of phi6 were allowed to evolve in either the presence or absence of sex for 250 generations. All experimental populations showed a significant increase in fitness relative to the ancestor, but sex did not increase the rate of adaptation. Rather, we found that the sexual and asexual treatments also differ because intense intrahost competition between viruses occurs during coinfection. Results showed that the derived sexual viruses were selectively favored only when coinfection is common, indicating that within-host competition detracts from the ability of viruses to exploit the host. Thus, sex was not advantageous because the cost created by intrahost competition was too strong. Our findings indicate that high levels of coinfection exceed an optimum where sex may be beneficial to populations of phi6, and suggest that genetic conflicts can evolve in RNA viruses. [TOP OF PAGE]

242. Characterization of the lysogenic bacteriophage MAV1 from Mycoplasma arthritidis. Voelker, L.L., Dybvig, K. (1998). J. Bacteriol. 180:5928-5931. The lysogenic bacteriophage MAV1, which is associated with the arthritogenicity of Mycoplasma arthritidis, was characterized. Several strains of M. arthritidis were examined for their ability to support growth of MAV1. A PFU assay was developed, and the sensitivity of phage to various chemical treatments was assayed. The most notable result was the resistance of MAV1 to proteinase K. The MAV1 genome is a double-stranded, linear DNA molecule of about 16 kb. The site of MAV1 DNA integration in the host chromosome was investigated. The ends of MAV1 DNA were cloned from three independent lysogens shown to have MAV1 DNA inserted at different sites in the host. The nucleotide sequences of the ends of the MAV1 genome and of the MAV1 DNA-chromosomal DNA junctions from each of three lysogens were determined. Sequences flanking the integrated prophage and the ends of native MAV1 DNA were determined, allowing the identification of the phage DNA (attP) and bacterial DNA (attB) recombination sites. Analysis of the left MAV1 DNA-chromosomal DNA junction sites showed a single-base heterogeneity located within MAV1 DNA sequences immediately adjacent to the attB sequence. A model for MAV1 integration-excision is proposed. [TOP OF PAGE]

243. Chemiluminescence patterns from bacterial cultures undergoing bacteriophage induced mass lysis. Vogel, R., Guo, X., Suessmuth, R. (1998). Bioelectrochemistry and Bioenergetics 46:59-64. Chemiluminescence from liquid culture media, as they are being used for the growth of microorganisms, is a common observation under aerobic conditions. During the growth of bacterial cells it is subjected to a process that leads to an almost complete elimination of the light emission. We report on a cancellation of this quenching process during mass lysis of cultures of the strains Escherichia coli B and Lactococcus lactis lactis 530-12 induced by the bacteriophages T7 and P530-12, respectively, leading to distinct light emission patterns. This cancellation does not occur with E. coli B when lysis occurs above a specific critical cell density. As cancellation can be induced by the addition of detergents to the lysate, this is probably due to the formation of membrane vesicles that continue quenching the chemiluminescence from the medium. [TOP OF PAGE]

244. Bacteriophage biology and bacterial virulence. Waldor, M.K. (1998). Trends in Microbiology 6:295-297. [TOP OF PAGE]

245. Identification and characterization of a newly isolated Shiga toxin 2-converting phage from Shiga toxin-producing Escherichia
     coli. Watarai, M., Sato, T., Kobayashi, M., Shimizu, T., Yamasaki, S., Tobe, T., Sasakawa, C., Takeda, Y. (1998). Infect. Immun. 66:4100-4107. [TOP OF PAGE]

246. Cell size-specific lysis of lake bacterioplankton by natural virus communities. Weinbauer, M.G., Höfle, M.G. (1998). Aquat. Microb. Ecol. 156:103-113. [TOP OF PAGE]

247. Significance of viral lysis and flagellate grazing as factors controlling bacterioplankton production in a eutrophic lake. Weinbauer, M.G., Hofle, M.G. (1998). Appl. Environ. Microbiol. 64:431-438. The effects of viral lysis and heterotrophic nanoflagellate (HNF) grazing on bacterial mortality were estimated in a eutrophic lake (Lake Plussee in northern Germany) which was separated by a steep temperature and oxygen gradient into a warm and oxic epilimnion and a cold and anoxic hypolimnion. Two transmission electron microscopy-based methods (whole-cell examination and thin sections) were used to determine the frequency of visibly infected cells, and a model was used to estimate bacterial mortality due to viral lysis. Examination of thin sections also showed that between 20.2 and 29.2% (average, 26.1%) of the bacterial cells were empty (ghosts) and thus could not contribute to viral production. The most important finding was that the mechanism for regulating bacterial production shifted with depth from grazing control in the epilimnion to control due to viral lysis in the hypolimnion. We estimated that in the epilimnion viral lysis accounted on average for 8.4 to 41.8% of the summed mortality (calculated by determining the sum of the mortalities due to lysis and grazing), compared to 51.3 to 91.0% of the summed mortality in the metalimninon and 88.5 to 94.2% of the summed mortality in the hypolimnion. Estimates of summed mortality values indicated that bacterial production was controlled completely or almost completely in the epilimnion (summed mortality, 66.6 to 128.5%) and the hypolimnion (summed mortality, 43.4 to 103.3%), whereas in the metalimnion viral lysis and HNF grazing were not sufficient to control bacterial production (summed mortality, 22.4 to 56.7%). The estimated contribution of organic matter released by viral lysis of cells into the pool of dissolved organic matter (DOM) was low; however, since cell lysis products are very likely labile compared to the bulk DOM, they might stimulate bacterial production. The high mortality of bacterioplankton due to viral lysis in anoxic water indicates that a significant portion of bacterial production in the metalimnion and hypolimnion is cycled in the bacterium-virus-DOM loop. This finding has major implications for the fate and cycling of organic nutrients in lakes. [TOP OF PAGE]

248. Size-specific mortality of lake bacterioplankton by natural virus communities. Weinbauer, M.G., Hoefle, M.G. (1998). Aquat. Microb. Ecol. 15:103-113. The potential effect that viral lysis has on the cell size distribution of bacterioplankton was investigated during late summer stratification in Lake Plusssee, Germany. Size-specific bacterial mortality due to viral lysis was estimated from in situ samples by a transmission electron microscopy based examination of visibly infected cells (VIC) and in an experiment with varying concentrations of the natural virus community. In all depth layers the highest percentage of cells was found in a cell length class that was smaller for the entire bacterial community (0.3-0.6 mu m) than for VIC (0.6-0.9 mu m). For cells <2.4 mu m the highest frequency of VIC (FVIC) was detected in the size classes 0.6-0.9 and 0.9-1.2 mu m, and the FVIC was high in the size classes 1.2-1.5 (all depth layers) and 1.5-1.8 mu m (meta- and hypolimnion). The estimated mortality due to viral lysis in these size classes was significant with maxima of 29 to 55% in the epilimnion, 30 to 59% in the metalimnion and 56 to 107% in the hypolimnion. In all depth layers the FVIC of bacteria <0.3 mu m in length was ca 30% of that averaged for the entire bacterial community, and in the experiment the percentage of cells <0.3 mu m was highest in enclosures with high viral activity. [TOP OF PAGE]

249. Bacteriophage diversity in the North Sea. Wichels, A., Biel, S.S., Gelderblom, H.R., Brinkhoff, T., Muyzer, G., Schutt, C. (1998). Appl. Environ. Microbiol. 64:4128-4133. In recent years interest in bacteriophages in aquatic environments has increased. Electron microscopy studies have revealed high numbers of phage particles (10(4) to 10(7) particles per ml) in the marine environment. However, the ecological role of these bacteriophages is still unknown, and the role of the phages in the control of bacterioplankton by lysis and the potential for gene transfer are disputed. Even the basic questions of the genetic relationships of the phages and the diversity of phage-host systems in aquatic environments have not been answered. We investigated the diversity of 22 phage-host systems after 85 phages were collected at one station near a German island, Helgoland, located in the North Sea. The relationships among the phages were determined by electron microscopy, DNA-DNA hybridization, and host range studies. On the basis of morphology, 11 phages were assigned to the virus family Myoviridae, 7 phages were assigned to the family Siphoviridae, and 4 phages were assigned to the family Podoviridae. DNA-DNA hybridization confirmed that there was no DNA homology between phages belonging to different families. We found that the 22 marine bacteriophages belonged to 13 different species. The host bacteria were differentiated by morphological and physiological tests and by 16S ribosomal DNA sequencing. All of the bacteria were gram negative, facultatively anaerobic, motile, and coccoid. The 16S rRNA sequences of the bacteria exhibited high levels of similarity (98 to 99%) with the sequences of organisms belonging to the genus Pseudoalteromonas, which belongs to the gamma subdivision of the class Proteobacteria. [TOP OF PAGE]

250. Measurements of DNA damage and photoreactivation imply that most viruses in marine surface waters are inefective. Wilhelm, S.W., Weinbauer, M.G., Suttle, C.A., Pledger, R.J., Mitchell, D.L. (1998). Aquat. Microb. Ecol. 14:215-222. The proportion of viruses in natural marine communities that are potentially infectious was inferred from the relationship between DNA damage and the loss of infectivity in marine viral isolates and measurements of the DNA damage in natural viral communities. Several viral isolates which infect marine Vibrio spp. were exposed to UV-C radiation and the concentration of cyclobutane pyrimidine dimers in the viral DNA was measured with a highly sensitive radioimmunoassay. The loss of infectivity in the UV-exposed isolates was also determined under conditions which either activated or repressed the blue light dependent photolyase enzyme in host cells in order to examine the damage-dependent response of this bacterial repair system. In addition, the accumulation of DNA photodamage during the solar day was measured in DNA isolated from natural viral communities collected along a transect in the western Gulf of Mexico. Using the correlation between DNA damage and infectivity for one of the viral isolates, we estimated the proportion of the natural viral community which was infective. The results imply that, due to light-mediated repair of damaged viral DNA by host-cell mechanisms (photoreactivation), greater than 50% of the viruses in natural communities are infective despite high rates of DNA damage. Furthermore, the accumulation of cyclobutane pyrimidine dimers was highest at the station where the surface mixed layer was shallowest, emphasizing the importance of mixing depth in relation to the accumulation of DNA damage. These experiments demonstrate that physical parameters such as mixing depth are critically interwoven with light penetration in influencing the infectivity of marine viral communities. [TOP OF PAGE]

251. Estimating the infectivity of marine viral communities from measurements of DNA damage and photoreactivation. Wilhelm, S.W., Weinbauer, M.G., Jeffrey, W.H., Suttle, C.A. (1998). Aquat. Microb. Ecol. 14:215-222. [TOP OF PAGE]

252. The role of sunlight in the removal and repair of viruses in the sea. Wilhelm, S.W., Weinbauer, M.G., Suttle, C.A., Jeffrey, W.H. (1998). Limnol. Oceanogr. 43:586-592. We investigated the in situ destruction rates of marine viral particles as well as the decay rates of infectivity for viral isolates along an similar to 400-km transect from oligotrophic offshore waters to productive coastal waters in the Gulf of Mexico. Light-mediated decay rates of viral infectivity averaged over the solar day ranged from 0.7 to 0.85 h super(-1) in surface waters at all stations and decreased with depth in proportion to the attenuation of UVB (305 nm). The destruction rates of viral particles also decreased with depth, although the rates of particle destruction were only 22-61% of infectivity when integrated over the mixed layer. The rates of viral particle destruction indicated that at three of four stations 6-12% of the daily bacterial production would have to be lysed in order to maintain ambient viral concentrations. At the fourth station, where there was a dense bloom of Synechococcus spp. and the mixed layer was shallower, 34-52% of the daily bacterial production would have to be lysed. A comparison of the difference between destruction rates of viral particles and infectivity integrated over the depth of the mixed layer implies that host-mediated repair must have restored infectivity to 39-78% of the sunlight-damaged viruses daily. The calculated frequency of contacts between viral particles and bacterial cells that resulted in infection (contact success) ranged from similar to 18 to 34% in offshore waters, where the frequency of contacts between viruses and bacteria was much lower, to similar to 1.0% at the most inshore station, where contact rates are much higher. This suggests that in offshore waters bacterial communities are less diverse, and that there is less selection to be resistant to viral infection. This paper provides a framework for balancing viral production, destruction, and light-dependent repair in aquatic viral communities. [TOP OF PAGE]

253. DNA analysis of temperate bacteriophage Aavariant phi23 isolated from Actinobacillus actinomycetemcomitans. Willi, K., Meyer, J. (1998). Molecular & General Genetics 258:323-325. The DNA of the temperate bacteriophage Aavariant phi23 isolated from the oral bacterium Actinobacillus actinomycetemcomitans was examined structurally both in the phage head and in the prophage. The DNA in phage particles comprises 44 kb linear molecules with a terminal redundancy of 1.6 kb, which represent circular permutations. Thus, DNA is packaged into phage heads by the headful mechanism. The Aavariant phi23 prophage is integrated into the host chromosome. [TOP OF PAGE]

254. Population dynamics of phytoplankton and viruses in a phosphate-limited mesocosm and their effect on DMSP and DMS production. Wilson, W.H., Turner, S., Mann, N.H. (1998). Estuarine, Coastal and Shelf Science 46 (Supplement a):49-59. The effect of phosphate limitation on viral abundance, phytoplankton bloom dynamics and production of dimethylsulphoniopropionate (DMSP) and dimethyl sulphide (DMS) was investigated in seawater mesocosm enclosures, in a Norwegian fjord, during June 1995. Daily estimates of viral concentrations, based on transmission electron microscope (TEM) counts, varied on an apparently random basis in each of the enclosures. A large Synechococcus spp. bloom developed in an enclosure which was maintained at a high N:P ratio, simulating phosphate-deplete growth conditions. Following phosphate addition to this enclosure, there was a large increase in estimated virus numbers shortly before an apparent collapse of the Synechococcus bloom. It is tentatively suggested that lysogenic viruses were induced following phosphate addition to the phosphate-limited enclosures, and that these observations add to a growing body of evidence which supports the hypothesis that nutrient availability may be responsible for the switch between lysogeny and lytic production. High DMS concentrations and viral numbers were observed on the demise of the flagellate (predominantly Emiliania huxleyi) and diatom blooms, but overall there was no significant correlation. Highest concentrations of DMSP were associated with blooms of E. huxleyi, for which an intracellular concentration of 0.5 pg cell^-1 (SD, 0.06) was calculated. Good correlation of DMSP with Synechococcus spp. cell numbers was observed, suggesting that these species of picoplankton may be significant producers of DMSP. No effects of phosphate limitation on DMS and/or DMSP production were evident from the data. [TOP OF PAGE]

255. Biochemical and genetic analysis of lambdaW, the newly isolated lambdoid phage. Wrobel, B., Srutkowska, S., Wegrzyn, G. (1998). Acta Biochimica Polonica 45:251-259. Otherwise isogenic Escherichia coli CP78 (relA+) and CP79 (relA-) strains are commonly used in studies on the stringent control, the bacterial response to amino acid starvation. We found that these strains are lysogenic for a phage which is spontaneously induced with a low frequency, producing virions able to infect other E. coli strains. Genetic studies, restriction analysis of the phage DNA genome, and electron microscopy revealed that this phage is very similar to, but not identical with, bacteriophage gamma. We called the newly isolated phage lambdaW, and found that most of CP78/CP79 ancestor strains are lysogenic for this phage. [TOP OF PAGE]

256. The effect of storage and ozonation on the physical, chemical, and biological characteristics of swine manure slurries. Wu, J.J., Park, S.H., Hengemuehle, S.M., Yokoyama, M.T., Person, H.L., Masten, S.J. (1998). Ozone Science & Engineering 20:35-50. The reduction of odor emanating from wasted swine manure is a very challenging environmental engineering problem. In an earlier work (Watkins et al., 1997), we showed the effect of ozone in reducing the odor and concentration of phenolic compounds in swine manure obtained from the pits under the slotted floors where the swine were housed. In this paper, we have expanded significantly upon the work of Watkins et al. by determining the effect of storage on the physical, chemical and biological characteristics of the swine manure slurry and whether the efficacy of ozonation is dependent upon storage time. [TOP OF PAGE]

257. Properties of mycobacteriophage MTPH11. Zhilenkov, E.L., Shemyakin, I.G., Stepanshina, V.N., Korobova, O.V., Oborotov, M.V., Dorozhkova, I.R. (1998). Mikrobiologiya 67:660-665. Some characteristics of the poorly studied phage MTPH11, which is used for identification of mycobacteria, are presented. The phage has an isometric head and a long noncontractile tail (B1 morphotype). The attachment apparatus of this phage includes a basal plate composed of two joint disks and a single tail fiber. The constant of phage adsorption on Mycobacterium smegmatis ATCC607 cells is 6.6 X 10-9 ml/min. The latent infection period in the MTPH11-host strain 607 system is 65 min; phage progeny ranges from 30 to 40 virions per one cell. The constant of phage inactivation with a homologous antiserum is 50 min-1. The buoyant density of intact MTPH11 virion in CsCl amounts to 1.520 g/cm3. The phage is susceptible to chloroform, retains lytic activity within a pH range of 5 to 9, and is resistant to inactivating agents. The G+C content of the phage DNA is 63 mol %. [TOP OF PAGE]

258. Svoistva mikobakteriofaga MTPN11 [Properties of MTPN11 mycobacteriophage]. Zhilenkov, E.L., Shemakin, I.G., Stepanshina, V.N., Korobova, O.V., Oborotov, M.V., Dorozhkova, I.R. (1998). Mikrobiologica 67:660-665. Some characteristics of the poorly studied phage MTPH11, which is used for identification of mycobacteria, are presented. The phage has an isometric head and a long noncontractile tail (B1 morphotype). The attachment apparatus of this phage includes a basal plate composed of two joint disks and a single tail fiber. The constant of phage adsorption on Mycobacterium smegmatis ATCC607 cells is 6.6 x 10(-9) ml/min. The latent infection period in the MTPH11-host strain 607 system in 65 min; phage progeny ranges from 30 to 40 virions per one cell. The constant of phage inactivation with a homologous antiserum is 50 min-1. The buoyant density of intact MTPH11 virion in CsCl amounts to 1.520 g/cm3. The phage is susceptible to chloroform, retains lytic activity within a pH range of 5 to 9, and is resistant to inactivating agents. The G + C content of the phage DNA is 63 mol%. [TOP OF PAGE]

259. Effect of plating medium and phage storage on mutant frequency and titer in the lambda cII transgenic mutation assay. Zimmer, D.M., Harbach, P.R., Mattes, W.B., Aaron, C.S. (1998). ironmental and Molecular Mutagenesis 32:325-330. We examined several experimental parameters of the lambda cI/cII transgenic mutation assay. In the assay, clear plaque lambda phage mutants are identified in a positive selection scheme following rescue of the lambda/LIZ shuttle vector from frozen tissues of Big Blue" transgenic mice. Mutant frequency and titer of phage from various tissues of control and ENU-treated animals was essentially the same on LB or TB1 plating medium, and storage of isolated DNA at 4 degrees C for up to 4 months did not affect either mutant frequency or titer. Storage of packaged phage for 28 days at 4 degrees C did not affect titer. The mean mutant frequency of packaged phage stored 28 days at 4 degrees C was consistently higher than phage plated the same day as packaging (day 0), though the difference was statistically significant in only two of the four samples tested. Reconstruction experiments in which numerically defined titers of known cII mutants were plated on both G1217 and G1225 E. coli strains and incubated at 37 degrees C or 24 degrees C showed highest titers on G1217 at 37 degrees C. The fraction of the G1217, 37 degrees C titer seen in the other strains and conditions varied widely with the cII mutation. [TOP OF PAGE]

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