Bacteriophage Ecology Group
Reference Abstracts (1998)
Dedicated to the ecology and evolutionary biology of the parasites of unicellular organisms (UOPs)
© Stephen T. Abedon
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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 si