Bacteriophage Ecology Group
Reference Abstracts (1991)
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. Assessing Ecological Risks of Biotechnology. Anonymous (1991). Butterworth-Heinemann, Boston.[TOP OF PAGE]

  2. Risk Assessment in Genetic Engineering. Anonymous (1991). McGraw-Hill, New York.[TOP OF PAGE]

  3. Practical Phage Control. ??? (1991). International Dairy Federation, [TOP OF PAGE]

  4. MOLECULAR CHARACTERIZATION OF THREE SMALL ISOMETRIC-HEADED BACTERIOPHAGES WHICH VARY IN THEIR SENSITIVITY TO THE LACTOCOCCAL PHAGE RESISTANCE PLASMID PTR2030. Alatossava, T., Klaenhammer, T.R. (1991). Appl. Environ. Microbiol. 57:1346-1353. Molecular characterization of three small isometric-headed bacteriophages which vary in their sensitivity to the lactococcal phage resistance plasmid pTR2030.Lactococcus lactis LMA12-4 is a pTR2030 transconjugant that has been used as an industrial starter culture because of its resistance to phages predominant in cheese plants. Plasmid pTR2030 intereferes with susceptible phages in this host strain via two mechanisms, restriction and modification (R/M) and abortive infection (Hsp). After prolonged use of LMA12-4 transconjugants in the industry, two different bacteriophages, designated nck202..vphi.48 (.vphi.48) and nck202..vphi.50 (.vphi.50), were isolated which could produce plaques on LMA12-4 containing pTR2030. In this study, these two phages were characterized and compared with a third phage, nck202..vphi.31 (.vphi.31), which is susceptible to both the R/M and Hsp activities encoded by pTR2030. Phage .vphi.48 was not susceptible to inhibition by Hsp, whereas .vphi.50 was unaffected by either the R/M or Hsp mechanisms. All three were small isometric-headed phages, but small differences were noted between the phages in the structural details of the tail base plate, susceptibility to chloroform treatment, and requirements for calcium infectivity. The phage genomes were all between 29.9 and 31.9 kb in length. Phages .vphi.31 and .vphi.48 harbored cohesive ends, whereas the phage .vphi.50 genome was circularly permuted, terminally redundant, and carried a putative packaging initiation site. DNA-DNA hybridization experiments conducted between the phages revealed a common region in .vphi.48 and .vphi.50 that may correlate with the resistance of the two phages to the Hsp-abortive infection induced by pTR2030. Phage .vphi.50 also harbored DNA sequences that shared homology to pTR2030 in the region where R/M activities have been localized on the plasmid. Molecular characterization of the three phages localized regions within the genomes of the pTR2030-resistant phages that may be responsible for circumventing plasmid-encoded Hsp and R/M defense mechanisms in lactococci. [TOP OF PAGE]

  5. Bacteriophage adsorption during transport through porous media: chemical perturbations and reversibility. Bales, R.C., Hinkle, S.R., Kroegar, T.W., Gerba, C.P., Gerba, C. (1991). Environ. Sci. Technol. 25:2088-2095. [TOP OF PAGE]

  6. Influence of environmental conditions on infection of Klebsiella pneumoniae by two different types of bacteriophages. Benedi, V.J., Regue, M., Alberti, S., Camprubi, S., Tomas, J.M. (1991). Canadian Journal of Microbiology 37:270-275. The adsorption and efficiency of plating of bacteriophages FC3-1 and FC3-9 on Klebsiella pneumoniae C3 (serotype O1:K66) cells grown at different pHs and temperatures were quantitated. Bacteriophage FC3-1, with lipopolysaccharide as its bacterial receptor, showed a large decrease in efficiency of plating on bacteria grown at low pH or low temperature. Under the same conditions, no significant decrease in efficiency of plating was found for bacteriophage FC3-9, a phage requiring capsule and lipopolysaccharide for its adsorption and carrying capsule-depolymerizing activity. We demonstrate that K. pneumoniae C3 cells grown at low pH or low temperature have less lipopolysaccharide exposed on their surface. We conclude that this is why lipopolysaccharide-specific phage FC3-1 less efficiently infects bacterial cells grown under those conditions. We propose that bacteriophage FC3-9 efficiently infects bacterial cells grown at low pH or low temperature because its enzymatic activity on the capsule makes lipopolysaccharide available to this phage. [TOP OF PAGE]

  7. The activity in the chicken alimentary tract of bacteriophages lytic for Salmonella typhimurium. Berchieri, A., Lovell, M.A., Barrow, P.A. (1991). Res. Microbiol. 142:541-549. Bacteriophages lytic for Salmonella typhimurium were isolated in considerable numbers from chickens experimentally infected with S. typhimurium, and in much lower numbers from the chicken feed. Lytic phages were also regularly isolated from human sewerage systems. One of these was used to inoculate S. typhimurium--infected two day-old chickens orally and via the feed. The phage took longer to establish in the caeca than did the Salmonella and it disappeared when the caecal S. typhimurium counts fell to 10(6) CFU/ml. No neutralizing antibodies to the phage were detected in the serum of these chickens. In a second experiment, five of 30 chickens similarly infected with S. typhimurium were inoculated with the phage. Within 3 days, the phage was isolated from 72% of the "in-contact" birds. A second phage, isolated from sewage, when inoculated into newly-hatched chickens simultaneously with any of 3 strains of S. typhimurium, produced a considerable reduction in mortality in the birds. This effect was only produced by inoculation of high concentrations of phage (greater than 10(10) PFU/ml). The phage produced reductions in the viable numbers of S. typhimurium in the crop, small intestine and caeca for up to 12 h after inoculation, with smaller reductions in bacterial numbers in the liver at 24 and 48 h after infection. ["Extended work on veterinary diarrhoea to Salmonella in poultry. . . Fewer chicks died . . . when . . . phages were given orally soon after the bacteria were administered." Quoted from Barrow & Soothill, 1997]. [TOP OF PAGE]

  8. Isolation and characterization of the bacteriophages of Lactic streptococci. Bhimani, R.S., Freitas, Y.M. (1991). Journal of Dairy Science 74:1461-1471. Four virulent phages of lactic streptococci were isolated from 245 samples of butter, buttermilk, curd, cheese, cheese whey, raw milk, and Srikhand. Three of these phages, i.e., FRC1, FRC2, and FRC3 isolated from buttermilk, curd, and Srikhand, respectively, lysed Streptococcus cremoris strains, and phage FRC4 isolated from cheese whey was specific for Streptococcus lactis ssp. diacetylactis. Phages were examined by electron microscopy. Isolated phages comprised of two morphological types. Phages FRC1 and FRC3 possessed prolate head, whereas polyhedral capsids were exhibited by phages FRC2 and FRC4. Noncontractile tails of all phages were 2 to 2.5 times longer than the head diameter, exhibiting regular fine striations and 20 to 30 annuli. Base plates with three or four spikes were visible in all phages. A structure of plug type was observed in phages FRC1 and FRC3. All phages were classified into group B of Bradley. Phages FRC1, FRC2, and FRC3 exhibited a latent period of 40 min, rise period of 20 min, and average burst size of 70 to 110 phage particles. Phage FRC4 possessed a latent period of 45 min, rise period of 15 min, and average burst size of 100 to 150 phage particles. Further differentiation among these phages was on the basis of eclipse phases, which were in the range of 26 to 32 min. [TOP OF PAGE]

  9. Effektivnost' bakteriofaga Klebsiella pneumoniae pri terapii eksperimental'noi klebsielleznoi infektsii.[The efficacy of Klebsiella pneumoniae bacteriophage in the therapy of experimental Klebsiella infection]. [Russian]. Bogovazova, G.G., Voroshilova, N.N., Bondarenko, V.M. (1991). Zhurnal Mikrobiologii, Epidemiologii i Immunobiologii 4:5-8. The effectiveness of specific phage therapy was studied on Klebsiella experimental sepsis in noninbred white mice, caused by the intraperitoneal injection of K. pneumoniae highly virulent strain K2 5055 into the animals. For treatment, Klebsiella polyvalent bacteriophage administered on day 2 after the infection of the animals with Klebsiella was used. The study revealed that bacteriophage could be detected in the blood and internal organs of the animals within 24 hours irrespective of the route of its administration: intraperitoneal, intravenous or intranasal. The bacteriophage preparation, introduced intraperitoneally, was shown to be effective in the treatment of generalized Klebsiella infection. One daily intraperitoneal injection of Klebsiella bacteriophage for 15-20 days proved to be the optimum scheme of treatment. In contrast to chemotherapeutic preparations, bacteriophages had no effect on normal microflora and did not aggravate dysbiotic disturbances. For this reason, bacteriophages may become one of alternative antimicrobial remedies, selectively affecting infective agents. [TOP OF PAGE]

  10. Development and application of new positively charged filters for recovery of bacteriophages from water. Borrego, J.J., Cornax, R., Preston, D.R., Farrah, S.R., McElhaney, B., Bitton, G. (1991). Appl. Environ. Microbiol. 57:1218-1222. Development and application of new positively charged filters for recovery of bacteriophages from water.Electronegative and electropositive filters were compared for the recovery of indigenous bacteriophages from water samples, using the VIRADEL technique. Fiber glass and diatomaceous earth filters displayed low adsorption and recovery, but an important increase of the absorption percentage was observed when the filters were treated with cationic polymers (about 99% adsorption). A new methodology fo virus elution was developed in this study, consisting of the slow passage of the eluent through the filter, thus increasing the contact time between eluent and virus adsorbed on the filters. The use of this technique allows a maximum recovery of 71.2% compared with 46.7% phage recovery obtained by the standard elution procedure. High percentages (over 83%) of phage adsorption were obtained with different filters from 1-liter aliquots of the samples, except for Virosorb 1-MDS filters (between 1.6 and 32% phage adsorption). Phage recovery by using samples, except for Virosorb 1-MDS filters (between 1.6 and 32% phage adsorption). Phage recovery by using the slow passing of the eluent depended on the filter type, with recovery ranging between 1.6% for Virosorb 1 MDS filters treated with polyethyleneimine and 103.2% for diatomaceous earth filters treated with 0.1% Nalco. [TOP OF PAGE]

  11. Principles of selective inactivation of viral genome. V. Rational selection of conditions for inactivation of the viral suspension infectivity to a given extent by the action of beta-propiolactone. Budowsky, E.I., Zalesskaya, M.A. (1991). Vaccine 9:319-325. The influence of the initial concentration of beta-propiolactone, the composition of the solution, temperature, and pH on the bacteriophage MS2 infectivity inactivation kinetics has been studied. Rate constants have been determined for the infectivity inactivation and for the change in the concentration (the consumption) of the reactant under inactivation conditions. These constants have been shown to permit a sufficiently precise description of the phage MS2 survival curves under the action of beta-propiolactone. These data have been used to put forward a kinetic approach for the rational determination of conditions for inactivation of the viral infectivity to a required extent with agents whose concentration decreases during inactivation as a result of hydrolysis and reactions involving the medium components. [TOP OF PAGE]

  12. Selection for benevolence in a host-parasite system. Bull, J.J., Molineux, I.J., Rice, W.R. (1991). Evolution 45:875-882. A paradigm for the evolution of cooperation between parasites and their hosts argues that the mode of parasite transmission is critical to the long-term maintenance of cooperation. Cooperation is not expected to be maintained whenever the chief mode of transmission is horizontal: a parasite's progeny infect hosts unrelated to their parent's host. Cooperation is expected to be maintained if the chief mode of transmission is vertical: a parasite's progeny infect only the parent's host or descendants of that host. This paradigm was tested using bacteria and filamentous bacteriophage (fl). When cells harboring different variants of these phage were cultured so that no infectious spread was allowed, ensuring that all parasite transmission was vertical, selection favored the variants that were most benevolent to the host - those that least harmed host growth rate. By changing the culture conditions so that horizontal spread of the phage was allowed, the selective advantage of the benevolent forms was lost. These experiments thus support the theoretical argument that mode of transmission is a major determinant in the evolution of cooperation between a parasite and its host. [TOP OF PAGE]

  13. Distinguishing mechanisms for the evolution of co-operation. Bull, J.J., Rice, W.R. (1991). J. Theor. Biol. 149:63-74. [TOP OF PAGE]

  14. Salmonella phage PSP3, another member of the P2-like phage group [published erratum appears in Virology 1992 May;188(1):414]. Bullas, L.R., Mostaghimi, A.R., Arensdorf, J.J., Rajadas, P.T., Zuccarelli, A.J. (1991). Virology 185:918-921. Freshly isolated DNA of phage PSP3, whose morphology closely resembles that of phage P2, contained both circular and linear molecules about 31 kb in length. Linear PSP3 DNA molecules possess single-stranded cohesive termini (cos). Sequencing of the fragment anticipated to contain cos revealed a 19-base sequence identical to cos of phage 186. Of the 107 bp to the right of cos, 94 were identical in 186 DNA (88% similarity), and of the 370 bp to the left, 229 were identical (62% similarity). Cos flanking sequences in both P2 and P4 were also highly conserved in PSP3. A number of restriction sites were at similar locations on the two phage DNAs. The parasitic phage P4 propagated on PSP3 lysogens. PSP3 integrates into the Escherichia coli chromosome at 27 min. [TOP OF PAGE]

  15. Isolation and characterization of bacteriophage FC3-10 from Klebsiella spp. Camprubi, S., Merino, S., Benedi, V.J., Tomas, J.M. (1991). FEMS Microbiol. Let. 83:291-298. FC3-10 is a Klebsiella spp. specific bacteriophage isolated on a rough mutant (strain KT707, chemotype Rd) of K pneumoniae C3. The bacteriophage receptor for this phage was shown to be the low-molecular mass lipopolysaccharide (LPS) fraction (LPS-core oligosaccharides), specifically the heptose content of the LPS inner-core. This is the first phage isolated on Klebsiella, the receptor for which is the LPS-core. This phage was unable to plate on Salmonella typhimurium LPS mutants with chemotypes Rd2 or Re showing imcomplete or no heptose content on their LPS-core, respectively. Spontaneous phage-resistant mutants from different Klebsiella strains were deep-rough LPS mutants or encapsulated revertants from unencapsulated mutant strains. [TOP OF PAGE]

  16. COLIPHAGES AND OTHER MICROBIAL INDICATORS IN STABILIZATION PONDS. Castillo, G.C., Trumper, B.A. (1991). Environmental Toxicology and Water Quality 6:197-208. Coliphages and other microbial indicators in stabilization ponds.Coliphages have been reported as promising indicators of viral inactivation in wastewater treatment. Their use in different aquatic environments, however, needs characterization prior to their application. The study of the behavior of coliphages in Chilean stabilization ponds is reported. The experimental system was a discontinuous reactor, subjected to the natural different climate conditions. Chile is temperate country and this study concentrated on the significantly different behavior of ponds during summer and fall seasons. Coliphages counts using Eschichia coli C (ATCC 13706) as host were compared to most probable number fecal coliforms, Salmonella and fecal streptococci. The results indicate that coliphages were more resistant to pond treatment than fecal coliforms and Salmonella. Furthermore, coliphages did not reflect climate changes as much as enteric bacteria did, as coliphage die-off rates during warm and cold seasons were 0.5 and 0.3 (Kb, day-1). Summer die-off rates of fecal coliforms (2.0, Kb, day-1) and Salmonella (1.7 Kb, day-1) drastically fell (0.6, Kb, day-1) in the fall. Coliphages and fecal steptococci removal tended to be similar, especially in cold season. It was observed that environmental factors, pH, dissolved oxygen, and algae biomass equally affected removal of all indicators, to different extents. These results suggest that to assess the microbiological efficiency of stabilization ponds, coliphages and fecal coliforms should be considered, as the first represents viral removal while the second represents pathogenic bacterial removal. Both parameters complement each other, particularly when important weather changes are expected. [TOP OF PAGE]

  17. Levels of selection, evolution of sex in RNA viruses, and the origin of life. Chao, L. (1991). J. Theor. Biol. 153:229-246. Multi-component RNA viruses have genomes that are segmented into two or more RNA molecules. A viral particle carries only one RNA molecule. Reproduction of a particle requires complementation by particles carrying other segments of the genome. Complementation is achieved when a group of particles co-infects the same host cell and forms a co-infection group. I have previously proposed the hypothesis that multi-component reproduction evolved in RNA viruses as a form of sex. Multi-component viruses may need sex because, like all RNA viruses, they have very high mutation rates. On the other hand, Nee (1987, J. molec. Biol. 25, 277-281.) has proposed the hypothesis that multi-component genomes evolved because smaller RNA molecules are favored by selection on RNAs within a host cell. Nee (1989, J. theor. Biol. 138, 407-412.) also claimed that selection on RNAs alone can account for the evolution of multi-component viruses. He criticized the viral sex hypothesis because, in his view, co-infection groups are not units of selection and are too transient to be engaged in sex. These two hypotheses were further examined through population genetic models. Three evolutionary agents are assumed to operate in the models. Selection on co-infection groups favors retention of the genome on one large RNA molecule because larger RNAs require less complementation. Selection on RNAs favor segmentation of the viral genome into smaller RNAs, which are replicated and encapsidated more rapidly. Mutation pressure also favors smaller molecules because those molecules are smaller targets for deleterious mutations. Analysis of the models shows that (when parameter values argued to be biologically realistic are used) selection on co-infection groups is necessary for the evolutionary persistence of multi-component viruses. Without selection on co-infections groups to oppose mutation pressure and selection on RNAs, a population of multi-component viruses is displaced by a population of parasitic viral RNAs that are replication and encapsidation specialists. These results support arguments that co-infection groups are units of selection in multi-component viruses. Both mutation pressure and selection on RNAs may be responsible for the evolution of genome segmentation in multi-component viruses because there is good evidence documenting the action of both in RNA viruses. [TOP OF PAGE]

  18. Phage abortive infection mechanism from Lactococcus lactis subsp. lactis, expression of which is mediated by an iso-ISS1 element. Cluzel, P.-J., Chopin, A., Ehrlich, S.D. (1991). Appl. Environ. Microbiol. 57:3547-3551. [TOP OF PAGE]

  19. Plasmid-encoded bacteriophage insensitivity in members of the genus Lactococcus with special reference to pCI829. Coffey, A., Costello, V., Fitzgerald, G., Daly, C. (1991). pp. 131-135. In In Dunny, G., Cleary, P., and McKay, L. (eds.), Genetics and Molecular Biology of Streptococci, Lactococci and Enterococci. ASM, Washington, DC. [TOP OF PAGE]

  20. Significance of several bacteriophage groups as indicators of sewage pollution in marine waters. Cornax, R., Morinigo, M.A., Balebona, M.C., Castro, D., Borrego, J.J. (1991). Water Res. 25:673-678. Seawater samples collected from two beaches with different levels of pollution were studied for the presence of classically and newly proposed fecal indicators such as total and fecal coliforms, fecal streptococci, coliphages, F-specific pahges and bacteriophages of Bacteroides fragilis. Total and fecal coliforms showed lower survival rates in seawater than fecal streptococci, F specific bacteriophages adn coliphages. On the other hand, total coliform concentrations were only higher than those of fecal coliforms in heavily polluted seawater, although in samples with a low level of pollution, fecal streptococci and Escherichia coli C phage counts were generally greater than those showed by fecal coliforms. The low concentration in which F-specific and B. fragilis bacteriophages were detected in marine waters compared to the E. coli bacteriophage levels, is an important shortcoming for the general use of the former microorganisms as universal indicators of fecal pollution. From the results obtained, it may be concluded that fecal streptococci and E. coli C bacteriophages are the most appropriate indicators of the remote pollution in marine waters. [TOP OF PAGE]

  21. Wide-spread occurrence and clonal variation in viruses which cause lysis of a cosmopolitan, eukaryotic marine phytoplankter Micromonas pusilla. Cottrell, M.T., Suttle, C.A. (1991). Mar. Ecol. Prog. Ser. 78:1-9. Seven clonal isolates of viruses which cause lysis of the eukaryotic, naked, photosynthetic flagellate Micromonas pusilla were isolated from the coastal waters of New York, Texas, California and British Columbia, as well as the oligotrophic waters of the central Gulf of Mexico. The viruses are large polyhedrons (ca 115 nm dia.) lacking tails, and are morphologically similar to a previously described virus (MPV) which infected M. pusilla . Restriction fragment analysis of the DNA from these clones using EcoRI revealed unique banding patterns, demonstrating that each of the clones (including 3 that were isolated from the same water sample) were genetically different. Summation of the 17 to 26 visible fragments from the restriction digests, for each of the clones, yielded estimated genomes sizes of 77 to 110 kilobase pairs. In contrast, only 4 different types of viruses could be recognized based on the molecular weights of the major proteins. In field samples the concentrations of viruses causing lysis of M. pusilla were found to be spatially and temporally variable, ranging from < 20 to 4.6 x 10 super(6) infective units/l. [TOP OF PAGE]

  22. Molecular evolution of bacteriophages discrete patterns of codon usage in T4 genes are related to the time of gene expresssion. Cowe, E., Sharp, P.M. (1991). J. Mol. Evol. 33:13-22. Patterns of codon usage in certain coliphages are adapted to expression in Escherichia coli. Bacteriophage T4 may be an exception to test the rule, as it produces eight tRNAs with specificities that are otherwise rare in E. coli. A database of all known T4 DNA sequences has been compiled, comprising 174 genes and a total of 115 kb (approximately 70% of the T4 genome). Codon usage has been examined in all T4 genes; some of these are known to be expressed before, and some after, the production of phage tRNAs. The results show two different patterns of codon usage: by comparison with the early genes, the late genes exhibit a shift in preference toward those codons recognized by the phage-encoded tRNAs. The T4 tRNAs translate A- ending codons, and it is possible that the phage acquired the tRNA genes because the mutation bias of the T4 DNA polymerase forces the T4 genome toward A + T-richness. [TOP OF PAGE]

  23. Comparison of lactococcal bacteriophage isolated in the United States and Argentina. De Fabrizio, S.V., Ledford, R.A., Shieh, Y.S.C., Brown, J., Parada, J.L. (1991). Int. J. Food Microbiol. 13:285-294. Bacteriophage of Lactococcus lactis ssp. lactis and ssp. cremoris, isolated in the United States and Argentina, were compared with respect to host range, adsorption, latent period, burst size and immunological cross-reactivity. Only 1 out of 13 U.S. culture isolates was sensitive to Argentinian phage. Argentinian L. lactis ssp. lactis C2 mutants were resistant to 13 U.S. phage isolates (4 prolate and 9 isometric). While Argentinian phage Stl-3 multiplied on U.S. culture isolate 59-1, low adsorption (38%) and insignificant burst size and latent period data were evident. Antisera prepared against U.S. phage D59-1 ( prolate) and F4-1 ( isometric) neutralized the lytic activities of all Argentinian prolate phage although the F4- 1 antiserum was less effective. The data suggest homology especially between U.S. phage D59-1 and the Argentinian phage. [TOP OF PAGE]

  24. REMOVAL OF FECAL INDICATOR BACTERIA AND BACTERIOPHAGES FROM THE COMMON MUSSEL MYTILUS-EDULIS UNDER ARTIFICIAL DEPURATION CONDITIONS. De Mesquita, M.M.F., Evison, L.M., West, P.A. (1991). J. Appl. Bacteriol. 70:495-501. Removal of fecal indicator bacteria and bacteriophages from the common mussel (Mytilus edulis) under artificial depuration conditions.Artificial self-purification (depuration) of mussels (Mytilus edulis) was undertaken at three temperatures, under conditions similar to those likely to be experienced in the commercial shellfish industry of the UK. During a 72 h depuration period, samples of mussel flesh were examined for three faecal indicator bacteria, Escherichia coli, Group D faecal streptococci and sulphite-reducing Clostridium spores, and two types of bacteriophage. There was a statistically significant difference in the elimination rate of faecal indicator bacteria compared with the slower rate for both bacteriophages. [TOP OF PAGE]

  25. Evaluation of an Escherichia coli host strain for enumeration of F male-specific bacteriophages. Debartolomeis, J., Cabelli, V.J. (1991). Appl. Environ. Microbiol. 57:1301-1305. A method was developed for the selective enumeration of F male- specific bacteriophages in samples of environment waters. The host strain for the phages, Escherichia coli HS(pFamp)R, has three antibiotic resistance markers, ampicillin on the Famp plasmid, which codes for pilus production, and streptomycin and nalidixic acid on the chromosome. The strain is resistant to coliphages T2 to T7 and .vphi.X174. More than 95% of the phages from environmental samples which plaqued on the host strain were F male specific. The host bacterium had a higher plaquing efficiency than E. coli K-12 Hfr for F-specific phages in stock suspensions and sewage effluents. The F male-specific phage levels in prechlorinated, secondary-treated sewage effluents generally were about 103 to 104 PFU/100 ml. The levels in the influents to the sewage treatment plants and in septic tank contents were about 105 PFU/100 ml. RNA-containing phages composed about 90% of the total F-specific phage population in sewage effluents. [TOP OF PAGE]

  26. Biological characterization of the lytic cycle of actinophage f-A7 in Streptomyces antibioticus. Diaz, L.A., Gomez, P., Hardisson, C., Rodicio, M.R. (1991). FEMS Microbiol. Let. 83:65-68. Some basic parameters of the lytic development of phage .vf.A7 in Streptomyces antibioticus are described. One-step growth experiments demonstrated that at 28oC .vf.A7 has latent period of about 60 min and an exponential growth period of about 35 min. The average burst size ranged from 70-100 plaque forming units per infected cell. At the same temperature 50% of the virions were adsorbed to germ tubes of S. antibioticus in about 10 min. This corresponds to an adsorption constant of 6.5 .times. 10-10 ml/min. The phage was unable to adsorb the host at other stages of the life cycle (spores or mycelium). Divalent cations are not required for .vf.A7 stability but Ca2+ proved to be essential for adsorption and also for a later stage of the vegetative development of the phage. [TOP OF PAGE]

  27. Single mutations in a gene for a tail fiber component of an Escherichia coli phage can cause an extension from a protein to a carbohydrate as a receptor. Drexler, K., Dannull, J., Hindennach, I., Mutschler, B., Henning, U. (1991). J. Mol. Biol. 219:655-663. [TOP OF PAGE]

  28. Dynamic roles of virus/phage in marine microbial ecosystems. Dundas, I., Bratbak, G., Heldal, M. (1991). Int. Marine Biotechnology Conf. (IMBC '91), Baltimore, MD (USA), 13-16 Oct 1991; PROGRAM AND ABSTRACTS. SECOND INTERNATIONAL MARINE BIOTECHNOLOGY CONFERENCE. There is a rapidly growing awareness of the importance of virus in the function of marine microbial ecosystems. The number of free viral particles varies with time and location from < 104 to > 108 per ml. and the fraction of the microbial cell population carrying mature virus particles, ranges from undetectable to more that 30%. From incubation experiments and from observed net changes in natural waters, we have estimated that the turnover rate of the viral population is about 2-6 hours during the growth season. Such results indicate that viruses are dynamically important partners in microbial ecosystems. At this stage we can not differentiate between virulent (lytic or continually produced) and temperate viruses. [TOP OF PAGE]

  29. Characteristics and some biological peculiarities of Klebsiella pneumoniae bacteriophage. Dzhaparidze, G.G., Chanishvili, T.G. (1991). Izvestiya Akademii Nauk Gruzii Seriya Biologicheskaya 17:50-53. Strictly specific and polyvalent clones of Klebsiella pneumonia bacteriophages were isolated and identified. The phage provides lysis of homologous strains of Klebsiella pneumonia bacteria in 92.3% of cases. Klebsiella pneumonia phage makes it possible to produce preparations for diagnostic, prophylactic and treatment purposes. [TOP OF PAGE]

  30. HOST RANGES OF FLORIDA ISOLATES OF BACTERIOPHAGES OF ERWINIA-CAROTOVORA. Eayre, C.G., Concelmo, D.E., Bartz, J.A. (1991). Phytopathology 81:1179 [TOP OF PAGE]

  31. The phage T4 nrdB intron: A deletion mutant of a version found in the wild. Eddy, S.R., Gold, L. (1991). Genes Dev. 5:1032-1041. [TOP OF PAGE]

  32. Use of modified diatomaceous earth for removal and recovery of viruses in water. Farrah, S.R., Preston, D.R., Toranzos, G.A., GIRARD, M., ERDOS, G.A., VASUHDIVAN, V. (1991). Appl. Environ. Microbiol. 57:2502-2506. Use of modified diatomaceous earth for removal and recovery of viruses in water.Diatomaceous earth was modified by in situ precipitation of metallic hydroxides. Modification decreased the negative charge on the diatomaceous earth and increased its ability to adsorb viruses in water. Electrostatic interactions were more important than hydrophobic interactions in virus adsorption to modified diatomaceous earth. Filters containing diatomaceous earth modified by in situ precipitation of a combination of ferric chloride and aluminum chloride adsorbed greater than 80% of enteroviruses (poliovirus 1, echovirus 5, and coxsachievirus B5) and coliphage MS2 present in tap water at ambient pH (7.8 to 8.3), even after filtration of 100 liters of tap water. Viruses adsorbed to the filters could be recovered by mixing the modified diatomaceous earth with 3% beef extract plus 1 M NaCl (pH 9). [TOP OF PAGE]

  33. Comparative inactivation of poliovirus type 3 and MS2 coliphage in demand-free phosphate buffer by using ozone. Finch, G.R., Fairbarn, N. (1991). Appl. Environ. Microbiol. 57:3121-3126. [TOP OF PAGE]

  34. A single amino-acid substitution in polyomavirus VP1 correlates with plaque size and hemagglutination behavior. Freund, R., Garcea, R.L., Sahli, R., Benjamin, T.L. (1991). J. Virol. 65:350-355. [TOP OF PAGE]

  35. Host-controlled modificaiton and restriction as a criterion of evaluating the therapeutical potential of Pseudomonas phage. Gachechiladze, K.K., others??? (1991). J. Basic Microbiol. 31:101-106. [TOP OF PAGE]

  36. Mortality of fecal bacteria in seawater. Garcia, L., Menon, P., Servais, P., Billen, G. (1991). Appl. Environ. Microbiol. 57:885-888. We propose a method for determining the mortality rate for allochthonous bacteria released in aquatic environments without interference due to the loss of culturability in specific culture media. This method consists of following the disappearance of radioactivity from the trichloroacetic acid-insoluble fraction in water samples to which 3Hthymidine-prelabeled allochthonous bacteria have been added. In coastal seawater, we found that the actual rate of disappearance of fecal bacteria was 1 order of magnitude lower than the rate of loss of culturability on specific media. Minor adaptation of the procedure may facilitate assessment of the effect of protozoan grazing and bacteriophage lysis on the overall bacterial mortality rate. [TOP OF PAGE]

  37. FATE OF VIRUSES IN TREATED SEWAGE EFFLUENT DURING SOIL AQUIFER TREATMENT DESIGNED FOR WASTEWATER RECLAMATION AND REUSE. Gerba, C.P., Powelson, D.K., Yahya, M.T., WILSON, L.G., Amy, G.L. (1991). Water Science and Technology 24:95-102. Fate of viruses in treated sewage effluent during soil aquifer treatment designed for wastewater reclamation and reuse.Land application or soil aquifer treatment of wastewater has been considered as a low-cost method for improving its quality for potential reuse. The objective of this work was to evaluate more quantitatively than in the past the fate and removal of viruses as they pass through the soil. A mini-basin (12 feet .times. 12 feet) was conducted at a site where secondary treated wastewater will be applied to large basins for underground storage. Suction samplers were placed at various depths in the upper 20 feet of the vadose zone directly beneath the mini-basin, and monitoring wells were placed at various distances (10 to 150 feet) from the mini-basin. Two experiments (August and September, 1990) were conducted where bacteriophage MS-2 and PRD-1 were added to the effluent before its application to the basins. High infiltration rate (up to 50 feet/day) and impeding layers at 15 ft resulted in nearly saturated flow conditions and up to 150 ft of horizontal transport of the viruses. The results also indicated that at least 90% removal of MS-2 and 99% removal of PRD-1 could be expected after movement of the sewage through 15 ft of soil and greater removal was observed at a slower infiltration rate (3 feet/day). [TOP OF PAGE]

  38. Electron microscopic study of Bacteroides nodosus pili and associated structures. Gradin, J.L., Sonn, A.E., Bearwood, D.E., Schmitz, J.A., Smith, A.W. (1991). American Journal of Veterinary Research 52:206-211. Surface structures of Bacteroides nodosus were examined by electron microscopy. Collodion film and chrome shadowing were used for maximizing the visualization of B nodosus pili and ring structures. The existence of B nodosus pili in foot rot lesions was confirmed. Contrary to previous reports, it was found that B nodosus pili production can be retained through serial broth transfer under certain conditions. Capsule production by B nodosus was irregular in that it could be either lacking or variable in thickness. A bacteriophage capable of infecting B nodosus also was detected. [TOP OF PAGE]

  39. CHARACTERISTICS OF PHAGE-RESISTANT MUTANTS OF THE SORBOSE PRODUCER GLUCONOBACTER-OXYDANS. GRIGOR'EVA, T.M., GAL'PERIN, M.Y., LOVCHEV, S., I, LAZAREV, A., V, Azizbekyan, R.R. (1991). Biotekhnologiya 7-9. Characteristics of phage-resistant mutants of the sorbose producer Gluconobacter oxydans.Mutants resistant simultaneously to Gs1 and Gs2 phages were isolated from Gluconobacter oxydans, sorbose producer. These strains had a different resistance to the phage Gs4, which had been isolated as a mutant with the wider host range from phage Gs2. Because phage resistance of strains correlated with reduction of sorbitol to sorbose conversion in about 90% cases, technological characteristics of phage-resistant mutants were studied. The clones corresponding to established parameters were isolated. [TOP OF PAGE]

  40. A bacteriophage-typing system for surveying the diversity and distribution of strains of erwinia-carotovora in potato fields. GROSS, D.C., POWELSON, M.L., REGNER, K.M., RADAMAKER, G.K. (1991). Phytopathology 81:220-226. A bacteriophage-typing system for surveying the diversity and distribution of strains of Erwinia carotovora in potato fields.A bacteriophage-typing system was developed and used to survey the diversity and distribution among strains of Erwinia carotovora subsp. carotovora and E. c. subsp. atroseptica from the rhizospheres and stems of potatoes [Solanum tuberosum] grown in the Columbia Basin of the Pacific Northwest. With a phage enrichment method and strains of E. carotovora from 25 serogroups as hosts, 13 phages displaying distinct host-range activities were isolated from potato and soil samples. In addition, a potatoe strain of E. chrysanthemi was used to isolate phage N (Ech-3), which did not infect strains of E. carotovora. All strains of E. c. atroseptica were sensitive to at least one of five phages, and strains in both subspecies of E. carotovora were sensitive to phage isolates C (304-32), E (101-1), and J (465-2-3-6). In three commercial fields in 1981, the phage groups occurring at midseason were AEJ, E, and EJ for E. c. atroseptica and G, GI, EF, and F for E. c. carotovora; total rhizosphere and stem populations of E. carotovora from symptomless plants ranged from 2 .times. 103 to 3 .times. 106 cfu/g (fresh weight) at midseason. In 1982, numbers of E. carotovora recovered from stems and rhizospheres increased from low and sporadic levels in late May to over 105 cfu/g (fresh weight) by early July. Phage group EJ of E. c. atroseptica was predominant among the strains from Norgold Russet and Russett Burbank seed tubers and it composed 35-43% of the total strains of E. carotovora recovered from rhizosphere and stem samples later in the season. No specific phage group was clearly associated with cultivar, date of isolation, and either rhizosphere or stem samples. Of the 389 strains of E. carotovora collected over a 2-yr period, 44% and 48% were typed, respectively, to one of 14 phage groups and one of nine serogroups. All strains of E. c. atroseptica were members of serogroup I, whereas IV and XXXVII were the two most common serogroups of E. c. carotovora. A few phage groups and serogroups were composed of the same strains, including phage group CDGIM and serogroup XVIII, phage groups E and EF and serogroup XXIX, and phage groups D and DL and serogroup XXXVII. [TOP OF PAGE]

  41. Properties of the streptomycete temperate bacteriophage FP43. Hahn, D.R., McHenney, M.A., Baltz, R.H. (1991). J. Bacteriol. 173:3770-3775. FP43 is a temperate bacteriophage for Streptomyces griseofuscus that forms plaques on many Streptomyces species. FP43 virions contain 56 kb of double-strand DNA that is circularly permuted and terminally redundant, and contains 65% G + C. A physical map of the FP43 genome was constructed, and the origin for headful packaging (pac) was localized to an 8.8-kb region of the genome (hft) that mediates high-frequency transduction by FP43 of plasmid pRHB101. The phage attachment site (attP), a replication origin (rep), a region that inhibits plaque formation (pin), and a 3-kb deletion (rpt) that caused a 100-fold reduction in plasmid transduction were mapped. [TOP OF PAGE]

  42. Ecology of bacteriophages infecting activated sludge bacteria. Hantula, J., Kurki, A., Vuoriranta, P., Bamford, D.H. (1991). Appl. Environ. Microbiol. 57:2147-2151. Little is known about the endemic bacteriophages of activated sludge. In this investigation 49 virus-host systems were studied by isolating co-occurring bacteria and bacteriophages from the aeration basin of a sewage treatment plant during 5 successive weeks. The phage titers were high and fluctuated during the time period. The occurrence of phage-sensitive and -resistant host did not depend on the presence or absence of phages. Several phage- host systems expressed variable plating efficiencies. In addition, phages with broad host ranges were observed. These results show that phages are an active part of this ecosystem and that they may exert selection pressure for phage resistance on their bacterial host populations. [TOP OF PAGE]

  43. Abundance of viruses in marine waters: assessment by epifluorescence and transmission electron microscopy. Hara, S., Terauchi, K., Koike, I. (1991). Appl. Environ. Microbiol. 57:2731-2734. [TOP OF PAGE]

  44. Production and decay of viruses in aquatic environments. Heldal, M., Bratbak, G. (1991). Mar. Ecol. Prog. Ser. 72:205-212. The quantitative significance of aquatic viruses in coastal and in lake water was investigated. The number of viruses in marine surface waters was found to change on a diurnal basis along with changes in number of bacteria and bacterial activity. By inhibiting the production of viruses, we were able to measure viral decay rates up to 1.1 h-1 in marine systems, and up to 0.6 h-1 in a freshwater lake, for the majority of the viral population. A minor fraction (4 to 40%) of the viral population was found to have decay rates lower than 0.05 h-1. The fraction of bacteria containing mature virus particles ranged from 2 to 16%, and the number of viruses released from these bacteria was on average about 50 (range 10 to 300). From these results we estimate that phages may lyse 2 to 24% of the bacterial population per hour. Phages may thus be a major cause of bacterial mortality in aquatic ecosystems and may have a significant impact on the carbon and nutrient flow in aquatic food webs. [TOP OF PAGE]

  45. COLIPHAGES AS ALTERNATE INDICATORS OF FECAL CONTAMINATION IN TROPICAL WATERS. Hernandez-Delgado, E.A., SERRA, M.L., Toranzos, G.A. (1991). Environmental Toxicology and Water Quality 6:131-144. Coliphages as alternate indicators of fecal contamination in tropical waters.Strong evidence has recently been found against the use of the fecal coliforms as indicator organisms of fecal contamination in tropical waters due to their indigenous nature in pristine waters. There is a great need for the development of more rapid, accurate, and low-cost techniques for determining bacteriological water quality. Coliphages seem to be an excellent alternative. We have developed a method to analyze large volumes of pristine water, which we compared to a commonly used direct method. It involves the filtration of water through positively charge filters and a virus-elution step. The eluent is then mixed with culture medium, a host bacterium, and incubated. We sampled pristine tropical rivers, water collected from bromeliads (epiphytic vegetation), sewage-contaminated waters, and marine waters. Concentrations of indicator bacteria were higher than recommended levels for recreational waters, including bromeliad waters. Indicators levels were higher in bromeliad waters than in sewage-contaminated rivers. Phages were isolated only from waters being used for recreational purposes and from sites known to be contaminated with domestic sewage, but not from pristine or bromeliad waters. These results suggest that there is a correlation between the presence of coliphages and fecal contamination. This further suggests that coliphages may be reliable indicators of fecal contamination in the environment. [TOP OF PAGE]

  46. Inactivation of T5 phage by cis-vaccenic acid, an antivirus substance from Rhodopseudomonas capsulata, and by unsaturated fatty acids and related alcohols. Hirotani, H., Ohigashi, H., Kobayashi, M., Koshimizu, K., Takahashi, E. (1991). FEMS Microbiol. Let. 61:13-17. The antiviral extract from Rhodopseudomonas capsulata was purified and the predominant active component was defined as cis-vaccenic acid (Cl-8:1 delta 11) by gas-liquid chromatography and gas chromatography-mass spectrometry analyses. Antiviral activities of unsaturated fatty acids and related alcohols against T5 phage were also tested. Among them, linoelaidic acid, oleic acid, and petroselenyl alcohol inactivated 98%, 53%, 67% of T5 phage at the concentration of 50 micrograms/ml, respectively. [TOP OF PAGE]

  47. Bacteriophages from China, an electron microscopical atlas. Ho, N.B., Si, Z.T., Yu, M.X. (1991). Science Press, Beijing.[TOP OF PAGE]

  48. Microbial strategies for intracellular survival. Hof, H. (1991). INFECTION 19 Suppl 4:S202-S205 Not only viruses but also certain bacteria, fungi as well as protozoa are able to reside and multiply within host cells; some of these microorganisms are facultative, others obligate intracellular hosts. They differ from each other in their mode of entry and in their strategies to survive intracellularly. Some remain in the phagocytic vacuole where they either block the fusion of lysosomes or resist the attack of the acidic milieu as well as the enzymatic digestion and multiply. Others escape from the vacuole to the cytoplasm where they travel around. This implies that chemotherapy has to respect these various intracellular life cycles. Therefore an antibiotic treatment can only be effective when the drug arrives in an active form at the special site of microbial residence. [TOP OF PAGE]

  49. PRESENCE OF CERTAIN BACTERIOPHAGES IN MOSQUITO LARVAL HABITATS INHIBITING THE LARVICIDAL ACTIVITY OF BACILLUS-THURINGIENSIS AND BACILLUS-SPHAERICUS. Hussein, M.E., Merdan, A., Razik, N.A.A., Morsy, S., Botros, M. (1991). Zentralblatt fuer Mikrobiologie 146:271-277. Presence of certain bacteriophages in mosquito larval habitats inhibiting the larvicidal activity of Bacillus thuringiensis and Bacillus sphaericus.12 water and/or mud samples from different mosquito habitats were tested for the presence of phages specific to Bacillus spp. 37 plaque morphologies were detected on B. thuringiensis. H-14, B. thuringiensis Berliner, B. sphaericus 1593, B. sphaericus IF-114. Samples number 1, 11, 12, 5 and 10 decreased the mortality rates of B. thuringiensis H-14 when added to the larvicidal bioassay system of Culex pipiens. Samples number 5, 11, 9, 12 inhibited the larvicidal activity of B. sphaericus. Ultrafiltrates of water samples, which harbored high numbers of the detected phages exerted more inhibition in the larvicidal potentiality of the tested entomopathogenic bacteria. [TOP OF PAGE]

  50. THE EFFECTS OF CERTAIN PHAGES OF BACILLUS-SPP ON THE LARVICIDAL POTENCY OF BACILLUS-THURINGIENSIS AND BACILLUS-SPHAERICUS. Hussein, M.E., Merdan, A., Razik, N.A.A., Morsi, S.A., Saleh, M.B. (1991). Journal of Applied Entomology 112:176-180. The effects of certain phages of Bacillus spp. on the larvicidal potency of Bacillus thuringiensis and Bacillus sphaericus.The phages: CP-51 and CP-54 of Bacillus cerus, together with P-4 and P-14 of B. sphaericus were tested against B. thuringiensis and B. sphaericus strains. P-4 and P-14 were more different in their host range than the other two phages. Results of the bioassay against Culex pipiens larvae presented the inhibition in the larvicidal effects of phage-infected bacteria. Such inhibitory action varied according to the phage and the entomopathogenic bacterial strains. [TOP OF PAGE]

  51. THE EFFECTS OF BACTERIOPHAGES IN NATURAL MOSQUITO LARVAL HABITATS ON THE LARVICIDAL POTENCY OF THE ENTOMOPATHOGENIC BACILLI BACILLUS-THURINGIENSIS AND BACILLUS-SPHAERICUS USED FOR COMMERCIAL FORMULATIONS. Hussein, M.E., Merdan, A., Razik, N.A., Morsy, S., Botros, M. (1991). Zentralblatt fuer Mikrobiologie 146:279-284. The effects of bacteriophages in natural mosquito larval habitats on the larvicidal potency of the entomopathogenic bacilli (Bacillus thuringiensis and Bacillus sphaericus) used for commercial formulations.Naturally present ditches of polluted and non-polluted mosquito breeding places were selected for this work. Water samples were collected before the spraying of the commercially used larvicides Bacillus thuringiensis H-14 and B. sphaericus 1593. Additional samples were obtained 72 h, 1 weeks, 2 week and 3 weeks after spraying. Phages for B. sphaericus only were detected after 72h and thereafter. The larvicidal effect on Culex pipiens larvae was inhibited significantly with B. sphaericus in the presence of phage-containing filtered water samples. Such inhibition increased with time. [TOP OF PAGE]

  52. Isolation of bacteriophage of Bacillus pumilus and studies on their properties. Jiang, R., Li, Z., Ma, J. (1991). Acta Microbiologica Sinica 31:176-182. Using B. pumilus 1037 and its derivative strains as host bacteria, 10 pp-phages had been isolated from environment in the plant. Serotype, host range, thermal stability and the effect of pH on survival of these phages were studied. The result showed that in fact there was a population of phages around the environment. Based on the relationships between pp-phage and different host bacteria, we deduced that phage fault in fermentation industry was caused by invasion of foreign bacteria at beginning. Therefore, the comprehensive measures in harness must be adopted in the industry to prevent and control the harmfulness of phages. [TOP OF PAGE]

  53. A putative RNA virus in Babesia bovis. Johnston, R.C., Farias, N.A., Gonzales, J.C., Dewes, H., Masuda, A., Termignoni, C., Amako, K., Ozaki, L.S. (1991). MOLECULAR AND BIOCHEMICAL PARASITOLOGY 45:155-158. Babesia bovis is an intraerythrocytic protozoan that causes bovine babesiosis. Agarose gel electrophoresis of nucleic acids extracted from two isolates of B. bovis reveals, besides bulk DNA, an ethidium bromide-stainable band at about 5.5 kb. Further characterization of the latter with DNase I, RNase and mung bean nuclease suggested it to be a double-stranded RNA. Sonicated parasites were fractionated in a CsCl buoyant density gradient. A sample containing the 5.5-kb RNA was analysed under an electron microscope and a virus-like particle was observed. [TOP OF PAGE]

  54. Enumeration of Flexibacter canadensis in environmental samples by using a bacteriophage isolated from soil. Jones, A.M., Knowles, R. (1991). Appl. Environ. Microbiol. 57:3043-3045. The denitrifier Flexibacter canadensis, in the presence of sulfide, can reduce N2O in the presence of concentrations of C2H2 which normally inhibit N2O reduction. Most-probable-number estimates of naturally occurring F. canadensis populations in various soils and sediments were made with a bacteriophage which is active against and specific for a strain of denitrifying F. canadensis (Is-11). Our survey suggests that F. canadensis is common in the natural environment. [TOP OF PAGE]

  55. Construction and characterization of derivatives carrying insertion mutations in F plasmid transfer region genes, trbA, artA, traQ, and trbB. KATHIR, P., IPPEN-IHLER, K. (1991). Plasmid 26:40-54. We devised a method for construction of insertion mutations in F plasmid tra region genes as a means of investigating the functions associated with previously uncharacterized loci. First, we constructed mutations in vitro, by insertion of a kanamycin resistance gene into a unique restriction site within a tra region fragment carried by a small, chimeric plasmid. Second, we crossed the insertion mutations, in vivo, onto a plasmid containing the complete F tra region sequence (either F lac, or pOX38, a Tra+ F plasmid derivative). Using this method, we obtained F lac mutant derivatives carrying KmR gene insertions in traQ, and a set of pOX38 mutant derivatives carrying a KmR gene insertion in trbA, artA, traQ, or trbB. Analysis of these derivatives showed that insertion of a kan gene at the NsiI site of traQ resulted in transfer deficiency, F-pilus-specific-phage resistance and an absence of detectable F-pilin subunit synthesis. Since the traQ mutants regained a wild-type phenotype when complemented with a traQ+ plasmid clone, we concluded that traQ expression is essential to transfer and F-pilus synthesis. However, pOX38 derivatives carrying kan gene inserts in genes trbA, artA, or trbB retained F-pilus-specific phage sensitivity and transferred at normal levels. Thus, these three gene products may not be essential for F-transfer from Escherichia coli K-12 under standard mating conditions. [TOP OF PAGE]

  56. Halobacterium halobium strains lysogenic for phage Phi H contain a protein resembling coliphage repressors. Ken, R., Hackett, N.R. (1991). Journal of Bacteriology [J. BACTERIOL. ] 173:955-960. DNA-binding proteins such as bacteriophage repressors belong to the helix-turn-helix family. Ionic interactions drive DNA binding, which means that repressors bind DNA most tightly at low salt concentrations. This raises the question of how gene expression might be regulated in obligate halophiles, which maintain internal salt concentrations of about 5 M. As a model system we have investigated the phage Phi H, which infects the archaebacterium Halobacterium halobium . Previous genetic data and transcriptional mapping had suggested a region of the phage genome where a repressor might bind. A modified electrophoretic mobility shift assay was used to identify an activity, present only in lysogens, that specifically binds this region. Methylation interference and DNA sequencing were used to identify four similar binding sites, which are arranged so that two copies of a dimer might bind on one face of the DNA helix. Binding of a protein at these sites could block RNA polymerase from initiating a transcript found only during lytic growth. [TOP OF PAGE]

  57. ??? Ketratanakul, A., Ohgaki, S., Yano, K. (1991). Water Sci. Technol. 24:407-??? [TOP OF PAGE]

  58. Isolation and characterization of lytic phages from Bacteroides ruminicola ssp brevis. Klieve, A.V., Gregg, K., Bauchop, T. (1991). Curr. Microbiol. 23:183-188. Two bacteriophages (.vphi.Brb01 and .vphi.Brb02), lytic to Bacteroides ruminicola ssp. brevis AR20, were isolated from sewage water. Both phages possessed polyhedral heads and long noncontractile tails, and were classified as Siphoviridae of morphotype B1. Bacteria resistant to phages .vphi.Brb01 and .vphi.Brb02 arose following lysis of broth cultures. Survivors of .vphi.Brb01 infection were capsulated but remained susceptible to .vphi.Brb02 infection. Survivors of .vf.Brb02 infection were noncapsulated and were resistant to attack by both .vf.Brb01 and .vphi.Brb02. Neither phage lysogenized the host. Both phages contained double-stranded DNA, and their restriction endonuclease digestion patterns indicated that the phage genomes were circularly permuted and terminally redundant. Phage .vf.Brb01 genome was examined in greater detail and confirmed to be circularly permuted, of size 33 kb, with a terminal redundancy of 2 kb, or 6% of the length of the genome. Circularly permuted genomes in phages of rumen bacteria do not appear to have been reported previously. At present, there is considerable interest in the genetic manipulation of rumen bacteria. The characterization of the phages described herein provides the basic information required for their use in the construction of vectors for the transfer of genetic material. [TOP OF PAGE]

  59. Phage resistance and altered growth habit in a strain of Streptococcus bovis. Klieve, A.V., Bauchop, T. (1991). FEMS Microbiol. Let. 64:155-159. Bacteriophage (phi Sb01) of Streptococcus bovis, isolated from pooled rumen fluid of cattle, was a small siphovirus of morphotype B1. It contained double-stranded DNA of length 30.9 kb, which was digested by the restriction endonucleases, EcoRI, HindIII, and PvuII. Bacteria which survived phi Sb01 infection (strain 2BAr) grew in long chains (100-200 cells), ultimately forming large clumps of cells. This growth habit was in distinct contrast to that of the parent host strain which grew predominantly in the form of single cells or diplococci. Strain 2BAr was genetically stable, resistant to phi Sb01 attack, and the observed differences in the growth characteristics of the parent strain and 2BAr indicated that cells of 2BAr were more adherent. In the rumen ecosystem, the selection of phage-resistant bacteria with altered growth characteristics may be a factor in modifying bacterial phenotypes, and thus increasing variability among bacteria which are closely related genetically. [TOP OF PAGE]

  60. Near on-line detection of enteric bacteria using lux recombinant bacteriophage. Kodikara, C.P., Crew, H.H., Stewart, G.S. (1991). FEMS Microbiol. Let. 67:261-265. The potential for a revolution in microbial testing can be perceived with the near on-line detection of indicator microorganisms. By definition, these are microorganisms present in significant numbers within a food which, while not pathogenic, can be related through increasing count to the increased probability of pathogen contamination. We have used recombinant lux+ bacteriophage to detect enteric indicator bacteria without recovery or enrichment in 50 min, provided that they are present at levels greater than 10(4) g-1 or cm-2. After a 4-h enrichment, samples having enteric counts of 10 g-1 or cm-2 can be distinguished from background. [TOP OF PAGE]

  61. Attachment and replication of Pseudomonas aeruginosa bacteriophages under conditions simulating aquatic environments. Kokjohn, T.A., Sayler, G.S., Miller, R.V. (1991). Journal of General Microbiology 137:661-666. Bacterial viruses are important in regulating bacterial population densities in natural aquatic environments, but the dynamics of bacteriophage-bacterial interactions in nature are poorly understood. In this study, the attachment and replication of three Pseudomonas aeruginosa bacteriophages (one temperate and two virulent) were investigated under conditions similar to those found in nature. Attachment and replication of bacteriophages were not impaired at host-cell densities equal to or lower (less than 105 c.f.u. ml-1) than those frequently found in aquatic environments when the host cells were physiologically competent to allow phage growth. Attachment (45-93%) to either actively growing or starved cells was not impaired in river water, indicating that attachment is efficient in natural freshwater habitats. However, the replication of bacteriophages was significantly altered in starved cells in river water: the latency period was extended (broth, 70-110 min; river water, 110- 240 min), and the burst size was reduced (broth, 27-65; river water 5-7). The findings of this study indicate that phages are likely to affect microbial ecology significantly in freshwater ecosystems. [TOP OF PAGE]

  62. Transduction: Mechanism and potential for gene transfer in the environment. Kokjohn, T.A. (1991). pp. 73-93. In In Levy, S.B. and Miller, R.V. (eds.), Gene Transfer in the Environment. McGraw-Hill, New York, N.Y. [TOP OF PAGE]

  63. [Isolation and characterization of Pseudomonas aeruginosa bacteriophage phikF77 mutants]. [Russian]. Kulakov, L.A., Balakshina, V.V., Morenkova, M.A., Zhulanova, E.I., Boronin, A.M. (1991). Genetika 27:1904-1911. It was found that phage phi kF77 is resistant to all known Pseudomonas aeruginosa restriction systems. Three types of mutants (dc-) which were unable to grow on different restrictive strains were isolated. All of them belong to one complementation group. Some of these mutations affected also the number of nicks in phage phi kF77 DNA and increased phage resistance to temperature treatment. It may be supposed that genes responsible for antirestriction mechanisms and introduction of nicks into DNA are connected in definite way. [TOP OF PAGE]

  64. Survival of bacteriophage 1 of the Salmonella typhimurium phage typing scheme in 4 different types of sterile soil. Leonardopoulos, J., Papaconstantinou, A., Papavassiliou, J. (1991). BOLLETTINO DELL ISTITUTO SIEROTERAPICO MILANESE 70:505-512. The survival of bacteriophage 1 of the Salmonella typhimurium phage typing scheme was studied in four different types of sterile soil at 4.20 and 37 degrees C. The longevity of the phage was generally short, not exceeding 36 days and depended on the temperature and the type of soil. [TOP OF PAGE]

  65. Characterization of fLC3, a Lactococcus lactis subsp. cremoris temperature bacteriophage with cohesive single-stranded DNA ends. Lillehaug, D., Lindqvist, B., Birkeland, N.K. (1991). Appl. Environ. Microbiol. 57:3206-3211. The temperate bacteriophage phiLC3, isolated from Lactococcus lactis subsp. cremoris, has an isometric head and a flexible tail containing 1 major protein and 8 minor proteins. Infection of a permissive L. lactis host strain yields a burst of about 50 phages per infected cell with a latent period of 60 min. A detailed restriction map of the phage chromosome was constructed by using 12 different restriction enzymes. The phage chromosome is a 33-kb linear double-stranded DNA molecule with unique cohesive ends and with a G + C content of 36.5%. Chemical sequencing of the DNA ends revealed 13-base 3' extended complementary single strands with a relatively high percentage of G + C. Pulsed-field gel electrophoretic analysis of DNA from a strain lysogenized with phiLC3 was used to localize the prophage to a 320-kb BamHI restriction endonuclease fragment from the host chromosomal DNA. This result indicates that lysogeny involves integration of the phage into the host chromosome. A spontaneous phiLC3 clear plaque mutant that was unable to give rise to lysogens was isolated. [TOP OF PAGE]

  66. Genetic relatedness of bacteriophage infecting Rhizobium galegae strains. Lindstom, K., Kaijalainen, S. (1991). FEMS Microbiol. Let. 82:241-246. Seven bacteriophage (.PHI.1R, .PHI.1OW, .PHI.3R, .PHI.30W, .PHI.1261M, .PHI.1261V and .PHI.gor3V), specific for the Rhizobium galegae species and representing three morphotypes, were isolated from different locations in Finland and in New Zealand. DNA was isolated from these phage and from phage .PHI.1R-3 and .PHI.1R;, which were derived from .PHI.1R in the laboratory, and analyzed by restriction endonuclease digestion and dot blot DNA hybridization. The sizes of the phage DNAs were estimated to range from 45.1-114.6 kb. The restriction patterns revealed four different phage genotypes, which correlated with the isolation hosts. DNA hybridization showed that the four genotypes were distantly related. The genotypes were distinguished when purified phage protein was analyzed in SDS-PAGE gels. [TOP OF PAGE]

  67. ??? Loayza, D., Carpousis, A.J., Krisch, H.M. (1991). Mol. Microbiol. 5:715-725. [TOP OF PAGE]

  68. Improved procedure for bacteriophage typing of Listeria strains and evaluation of new phages. Loessner, M.J. (1991). Appl. Environ. Microbiol. 57:882-884. A modified technique in listerial phage typing, termed reversed phage typing procedure, was developed. Ready-to-use typing plates were prepared by preapplication of phage suspensions on tryptose agar plates. The new procedure offers a number of substantial advantages as compared with the conventional method, being much more reliable, efficient, and convenient to use. More than 1,000 strains of Listeria have thus far been typed with the reversed phage typing procedure, employing an extended set of 21 genus-specific bacteriophages. The overall typability of strains was 89.5%. [TOP OF PAGE]

  69. Bacteriophages for incompatibility group H plasmids morphological and growth characteristics. Maher, D., Sherburne, R., Taylor, D.E. (1991). Plasmid 26:141-146. Two independently isolated temperature-sensitive bacteriophage that are specific for enterobacterial hosts harboring HI and HII plasmids were characterized to determine if any identifiable differences existed between them. The traits examined included adsorption pattern of phage to H pili, bacteriophage size, sensitivity to chloroform, RNA strandedness, reaction with F-specific antiphage serum, virion protein pattern, temperature range of lytic ability, and plaque morphology. No differences between the phages were observed for any of the features analyzed. Ecological questions on the origin and maintenance of temperature-sensitive phages are discussed. [TOP OF PAGE]

  70. LYOPHILIZATION OF 01 AND NON-O1 VIBRIO-CHOLERAE PHAGES. Makedonova, L.D., Kudryakova, T.A., KADETOV, V., V, NATALICH, L.A. (1991). Kriobiologiya 34-40. Lyophilization of 01 and non-O1 Vibrio cholerae phages.A regimen of freeze-drying and sublimation has been developed, optimal protective media have been selected for lyophilization of moderate 01 and non 01 Vibrio cholerae phages. [TOP OF PAGE]

  71. VIRUCIDAL ACTIVITY OF DISINFECTANTS ON BACTERIOPHAGES CONTAMINATING INERT SURFACES. MARIS, P. (1991). Sciences des Aliments 11:17-24. Virucidal activity of disinfectants on bacteriophages contaminating inert surfaces.A simple method was developed to ascertain more precisely how disinfectants in the food industry are active on bacteriophages contaminating inert surfaces. Four the eight commercial compounds and three reference products tested, the virucidal concentrations were one to five times higher than the concentrations obtained by the quantitative suspension test NF-T-72-181. In the presence of milk, the active concentrations were 4 to 32 times, even more than 80 times higher than the usually recommend doses. [TOP OF PAGE]

  72. RELATIONSHIP BETWEEN CLASSICAL INDICATORS AND SEVERAL PATHOGENIC MICROORGANISMS INVOLVED IN SHELLFISH-BORNE DISEASES. MARTINEZ-MANZANARES, E., Morinigo, M.A., Cornax, R., EGEA, F., Borrego, J.J. (1991). Journal of Food Protection 54:711-717. Relationship between classical indicators and several pathogenic microorganisms involved in shellfish-borne diseases.Quantitative relationships between classical indicators and the main pathogenic microorganisms involved in shellfish-borne diseases were established from shellfish samples (cockles, Cardium edule and striped venus, Chamelea gallina) collected from five sampling stations located at different depths in the estuary of Guadalhorce river (Malaga, Spain). F-ANOVA analyses applied to the variables: seasons, depth, and sampling stations, showed that a significant relationship could be established only between the season of the year and the concentrations of total anaerobic bacteria, coliphage, and Aeromonas hydrophila. Classical indicators present no significant correlation with the pathogenic microorganisms in shellfish samples, which questions the existence of a universal indicator of shellfish hygiene. However, from the lineal correlations between detection percentages of pathogens and the medians of the lognormal distribution (XX50) of the indicators, it can be deduced that the use of three indicators, Escherichia coli, fecal streptococci, or coliphages, is valid to establish the potential health hazard associated with the presence of Salmonella, Vibrio parahemolyticus, and Staphylococcus aureus in shellfish samples. [TOP OF PAGE]

  73. BACTERIOLOGICAL QUALITY OF GROUNDWATER IN CEMETERIES. Martins, M.T., PELLIZARI, V.H., PACHECO, A., MYAKI, D.M., ADAMS, C., BOSSOLAN, N.R.S., MENDES, J.M.B., HASSUDA, S. (1991). Revista de Saude Publica 25:47-52. Bacteriological quality of groundwater in cemeteries.Groundwater samples collected by piezometers from three cemeteries in geologically distinct areas of S. Paulo and Santos, Brazil, were analysed in order to determine their hygienic and sanitary conditions. Fecal coliformes, fecal streptococci, sulfite reducer clostridia and Salmonella were searched for the purpose of evaluating sanitary conditions, and total coliforms, heterotrophic bacteria, proteolitic and lipolitic microorganisms for evaluating hygienic conditions. In some samples, nitrate levels were also determined. It was discovered that these waters do not present adequate sanitary and hygienic conditons and that, in some cases, nitrate levels were extremelly high (75.7 mg/l). In most samples, higher levels of fecal streptococci and sufite reducer clostridia than fecal coliforms were detected, which seems to show that the two former indicators would be more appropriate for evaluating the sanitary conditions of this kind of water. Salmonella were detected in only one of 44 samples analysed and coliphages in none. In the stastical analysis, the correlation matrix showed significant correlations among three fecal pollution indicators, as well as among anaerobic and aerobic heterotrophs and lipolitic bacteria. A direct relationship between the deterioration of water quality and the geological and hydrogeological conditions of the environment studied was observed. When coemeteries are constructed these conditions should, therefore, be taken into consideration. [TOP OF PAGE]

  74. Eukaryotic algae. Meints, R.H., Van Etten, J.L. (1991). pp. 883-888. In In Levin, M.A., Seidler, R.J., and Rogul, M. (eds.), Microbial Ecology: Principles, Methods and Applications. McGraw-Hill, Inc., New York. [TOP OF PAGE]

  75. THE ROLE OF LIPOPOLYSACCHARIDE IN COMPLEMENT-KILLING OF AEROMONAS-HYDROPHILA STRAINS OF SEROTYPE O 34. Merino, S., Camprubi, S., Tomas, J.M. (1991). Journal of General Microbiology 137:1583-1590. The role of lipopolysaccharide in complement-killing of Aeromonas hydrophila strains of serotype O:34.The role of lipopolysaccharide (LPS) in the susceptibility of Aeromonas hydrophila strains of serotype O:34 to non-immune human serum was investigated using isogenic mutants (serum-sensitive), previously obtained on the basis of phage resistance, and characterized for their surface components. The classical complement pathway was found to be principally involved in the serum-killing of these sensitive strains. LPS preparations from serum-resistant or serum-sensitive strains, or purified core oligosaccharides (low-molecular-mass LPS) inactivated both bactericidal and complement activity of whole serum, while the O-antigen molecules (high-molecular-mass LPS) did not. The results indicate that LPS core oligosaccharide composition contributes to complement resistance of A. hydrophila strains from serotype O:34 with moderate virulence. [TOP OF PAGE]

  76. Preliminary observations on the concentration of marine bacteriophages in the water around Helgoland. Moebus, K. (1991). Helgol. Meeresunters. 45:411-422. In a preliminary survey, conducted between August 28 and October 9, 1990, the concentration of bacteriophages in seawater sampled at intervals of 1 to 4 days near Helgoland (station Kabeltonne) was determined by using indicator bacteria which had been isolated from seawater sampled only some weeks before. With a number of bacterial strains, phage concentrations ranging between 2 and 7 x 10 super(2)/ml were found. However, during the course of this investigation maximal concentrations lasted for a few days only. With most indicator bacteria employed, the concentration of plaque-forming units (PFU) varied in the range of < 1 and 20-30 PFU/ml. [TOP OF PAGE]

  77. Host-parasite interactions: Recent developments in the genetics of abortive phage infections. Molineux, I.J. (1991). New Biologist 3:230-236. [TOP OF PAGE]

  78. The effect of cyanophages on the growth and survival of Lyugbya wollei, Anabaenaflos- aquae, and Anabaena circinalis. Monecue, R.L., Phlips, E.J. (1991). J. Aquat. Plant. Manage. 29:88-93. Not sure if following constitutes abstract: Three newly isolated cyanobacteria viruses tested on hHe organisms in laboratory culture experiments. "Cyanophage LW 1 significantly reduced the growth and survival of L. toollei...." Inhibition of growth occurred within 7 days and chlorophyll a concentrations were reduced 95% (relative to controls) within 14 days of inoculahon. (quoted from http://nosferatu.cas.usf.edu/chemistry/info_research_resources/ies/LYNGBYA.html). [TOP OF PAGE]

  79. Lipopolysaccharide is the receptor for kappa phage in Serratia marcescens. Montilla, R., Williams, R.P., Loren, J.G., Vinas, M. (1991). Antonie van Leeuwenhoek 59:15-18. Kappa phage active on Serratia marcescens can form plaques on white and red strains with identical efficiencies. To identify the kappa phage receptor, the inactivation of the phage was studied after incubation with several bacterial subcellular fractions. The experiments demonstrated that kappa phage adsorbs to outer membrane fractions of susceptible cells. Proteinase K did not affect the rate of inactivation. Lipopolysaccharide proved to be the primary receptor for kappa phage. Prodigiosin content of the lipopolysaccharide fraction was low. [TOP OF PAGE]

  80. Physiological, morphological, and physicochemical characterization of a novel Escherichia coli bacteriophage, phage MM. Muller, M., Wurtz, M., Kellenberger, E., Aebi, U. (1991). Journal of Structural Biology 106:17-30. A double-stranded DNA containing, T even-like, Escherichia coli bacteriophage, called MM, has been isolated from the local sewage and purified by polyethylene glycol precipitation followed by banding on a cesium chloride three-step gradient. It yields a burst size of 75 particles per infected cell, and has an adsorption coefficient of 3.3 x 10(-10) cm3/min and a latent period of 45 min. Electron microscopy of phage MM reveals an isometric icosahedral head, 92 nm long and 81 nm wide, and a 112-nm-long contractile tail with six pairs of 40-nm-long fibers attached to its baseplate. Phage MM appears similar to E. coli phage T4 or Salmonella phage O1. The density of phage MM in cesium chloride is 1.515 g/ml, and its total mass is 144 MDa. Gel electrophoresis of purified MM capsids displays two major capsid proteins in approximately equimolar amounts and with apparent molecular masses of 38 and 15 kDa. Similarly, purified MM tails yield two major polypeptides with apparent molecular masses of 55 and 16 kDa, most likely representing the major tail sheath and tail tube polypeptides. Its double-stranded DNA has a G-C content of 50%, a length of 131 kilobases (kb), and a mass of 89 MDa. [TOP OF PAGE]

  81. EXPERIMENTAL CONTROL OF BACTERIAL BLOTCH BY BACTERIOPHAGES. Munsch, P., OLIVIER, J.L., HOUDEAU, G. (1991). 35891/MAHER, M. J. (ED. ). MUSHROOM SCIENCE, VOL. XIII. SCIENCE AND CULTIVATION OF EDIBLE FUNGI, VOLS. 1 AND 2; 13TH INTERNATIONAL CONGRESS, DUBLIN, IRELAND, SEPTEMBER 1-6, 1991. XX+442P. (VOL. 1); IX+403P. (VOL. 2) A. A. BALKEMA: ROTTERDAM, NETHERLANDS; BRO 389-396. [TOP OF PAGE]

  82. HYDRAULIC AND MICROBIOLOGICAL CHARACTERIZATION OF REACTORS FOR UV DISINFECTION OF SECONDARY WASTEWATER EFFLUENT. Nieuwstad, T.J., Havelaar, A.H., Van Olphen, M. (1991). Water Res. 25:775-784. Hydraulic and microbiological characterization of reactors for UV disinfection of secondary wastewater effluent.The efficiency of 5 different types of u.v. reactors for disinfecting secondary effluent was tested in continuous experiments lasting 4-10 weeks. The units were hydraulically characterized by tracer stuides and microbiologically calibrated by measuring the inactivation of a model organism, for which the F-specific RNA bacteriophage MS2 was used. All units could be described as a number of completely mixed tanks in series in which the inactivation follows first-order kinetics in both the number of organisms and the u.v. dose. The u.v. dose could be calculated from the product of the average retention time and the average u.v. intensity in the reactor. The average u.v. intensity could be calculated using the infinite line source model and the extinction coefficient of the water measured in unfiltered samples, which varied between 90 and 140 m-1 (transmittance 1 cm cuvette between 25 and 40%). From experiments with naturally polluted secondary effluent, inactivation rate constants for the vegetative bacteria Escherichia coli and faecal streptococci of 0.0055 and 0.0029 m2/J (log10-base), respectively, were found. For the bacterial spores of sulphite-reducing clostridia this constant was 0.00063 m2/J and for somatic coliphages and F-specific bacteriophages values of 0.0069 and 0.023 m2/J, respectively, were found. Enteroviruses were usually inactivated below the level of detection (1 PFU/101), hence no quantitative results can be presented. The inactivation rate constant for reoviruses was 0.0024 m2/J, very close to the constant for F-specific bacteriophages, which makes the latter organisms, which are relatively easy to count, very suitable as an indicator organism for virus inactivation by u.v. radiation. The inactivation rate constant for a pure culture of MS2 was 0.0046, which is twice the value for F-specific phages as naturally occurring in sewage. This emphasizes the need to design u.v. reactors on the basis of data obtained with effluents rather than laboratory-strains of micro-organisms. [TOP OF PAGE]

  83. Virus ecology. Olofsson, S., Kjelleberg, S. (1991). Nature 351:612-612. [TOP OF PAGE]

  84. The implications of horizontal gene transfer in the environmental impact of genetically engineered microorganisms. Olson, B.H., Ogunseitan, O.A., Rochelle, P.A., Tebbe, C., Tsai, Y.L. (1991). p. ???-??? In Levin, M. and Strauss, H. (eds.), Risk Assessment in Genetic Engineering: Environmental Release of Organisms. McGrawHill, New York. [TOP OF PAGE]

  85. Isolation and characterization of bacteriophage FJ-1 of Lactobacillus plantarum. Onda, T., Ito, K., Niimura, Y., Uchimura, T., Kozaki, M. (1991). Journal of Agricultural Science Tokyo Nogyo Daigaku 35:250-255. Bacteriophage Fj-1 of Lactobacillus plantarum 1759 was isolated from silage, and formed to Bradley's group B. Electron microscopy showed an isometric head (diameter, 40 nm) and long non-contractile tail (150 nm). Fj-1 genome was a double-stranded DNA. The latent period for phage development was approximately 60 min and it's burst size was about 90-100 phages. Fj-1 phage has a broad host range in Lactobacillus plantarum strains. [TOP OF PAGE]

  86. COLIPHAGE AND BACTERIOPHAGE AS INDICATORS OF RECREATIONAL WATER QUALITY. Palmateer, G.A., Dutka, B.J., Janzen, E.M., Meissner, S.M., Sakellaris, M.G. (1991). Water Res. 25:355-357. Coliphage and bacteriophage as indicators of recreational water quality.Five popular beaches in southwestern Ontario, Canada, were investigated for the presence of coliphage, bacteriophage and the standard bacterial indicators of fecal waste. Using current phage enumeration techniques, both coliphage and bacteriophage were recovered at all five beaches on each of ten sampling trips. Coliphage and bacteriophage results were available in 6 and 18 h, respectively. Based on recent reports on the association of coliphage and bacteriophage with enteroviruses in surface waters, and the consistent occurrence of both coliphage and bacteriophage at the five beaches investigated, future studies, on the determination of health risks related to bathers, should involve virological analyses including the enumeration of coliphage and bacteriophage. [TOP OF PAGE]

  87. Two-stage fermentation with bacteriophage l as an expression vector in Escherichia coli. Park, T.H., Seo, J.-H., Lim, H.C. (1991). Biotechnology & Bioengineering 37:297-302. [TOP OF PAGE]

  88. Genetic significance of viruses in the marine environment. Paul, J.H., Jiang, S.C., Rose, J.B. (1991). Int. Marine Biotechnology Conf. (IMBC '91), Baltimore, MD (USA), 13-16 Oct 1991; PROGRAM AND ABSTRACTS. SECOND INTERNATIONAL MARINE BIOTECHNOLOGY CONFERENCE. Viruses are now known to be abundant in aquatic environments, where they are believed to play a role in controlling bacterial and algal populations by infection and lysis. It is not known if viruses are a significant component of the dissolved (< 0.2 mu m) DNA pool. We have developed a method to concentrate both viruses and dissolved DNA from aquatic environments by vortex flow filtration (VFF). Recoveries of T2 phage and calf thymus DNA added to artificial seawater averaged 72.8 and 80%, respectively. Viral abundance in samples concentrated by VFF and determined by TEM ranged from < 10 super(6) for a sample taken at a 1500 m depth from the Gulf of Mexico to 3.4 x 10 super(7)/ml for a Tampa Bay sample. [TOP OF PAGE]

  89. Concentration of viruses and dissolved DNA from aquatic environments by vortex flow filtration. Paul, J.H., Jiang, S.C., Rose, J.B. (1991). Appl. Environ. Microbiol. 57:2197-2204. Vortex flow filtration (VFF) was used to concentrate viruses and dissolved DNA from freshwater and seawater samples taken in Florida, the Gulf of Mexico, and the Bahamas Bank. Recoveries of T2 phage and calf thymus DNA added to artifical seawater and concentrated by VFF were 72.8 and 80%, respectively. Virus concentrations determined by transmission electron microscopy of VFF-concentrated samples ranged from 3.4 .times. 107/ml for a eutrophic Tampa Bay sample to 2.4 .times. 105 for an oligotrophic oceanic surface sample from the southeastern Gulf of Mexico. Viruslike particles were also observed in a sample taken from a depth of 1,500 m in the subtropical North Atlantic Ocean. Filtration of samples through Nucleopore or Durapore filters (pore size, 0.2 .mu.m) prior to VFF reduced phage counts by an average of two-thirds. Measurements of dissolved-DNA content by Hoechst 33258 fluorescence in environmental samples concentrated by VFF yielded values only ca. 35% of those obtained for samples concentrated by ethanol precipitation (the standard dissolved-DNA method). However, ethanol precipitation of VFF-concentrated extracts resulted in an increase in measurable DNA, reaching 80% of the value obtained by the standard method. These results indicate that a portion of the naturally occurring dissolved DNA is in a form inaccessible to nucleases and Hoechst strain, perhaps bound to protein or other polymeric material, and is released upon ethanol precipitation. Viral DNA contents estimated from viral counts averaged only 3.7% (range, 0.9 to 12.3%) of the total dissolved DNA for samples from freshwater, estuarine, and offshore oligotrophic environments. These results suggest that viruses are not a major component of the dissolved DNA, although they may be involved in its production by lysis of bacterial and phytoplankton cells. [TOP OF PAGE]

  90. FATE OF HUMAN ENTERIC VIRUSES COLIPHAGES AND CLOSTRIDIUM-PERFRINGENS DURING DRINKING-WATER TREATMENT. Payment, P. (1991). Canadian Journal of Microbiology 37:154-157. Fate of human enteric viruses, coliphages, and Clostridium perfringens during drinking-water treatment.The elimination of human enteric viruses, coliphages, and Clostridium perfringens was studied during a conventional complete drinking-water treatment process. The respective concentrations (geometric mean) of these microorganisms in 100-L samples of river water were, respectively, as follows: viruses, 79 mpniu (most probable number of infectious units) per 100 L, coliphages, 6565 pfu (plaque-forming units) per 100 L, and clostridia, 11,349 (colony-forming units) per 100 L. After predisinfection, flocculation with alum, and settling, human enteric viruses were not detected in any of the 100-L samples (< 4 mpniu/100 L), but coliphages were detected in 7 of 14 samples and clostridia in 15 of 16 samples. In filtered water samples, human enteric viruses were detected in 2 of 31 samples, coliphages in 10 of 33, and clostridia in 17 of 33. Finished water was free of human enteric viruses (0/162 samples), but coliphages were detected in one sample (1.54 pfu/100 L) and clostridia in three, at 1.0, 4.1, and 7.0 cfu/100 L. It thus appears that coliphages and clostridia, which are present in larger numbers than viruses in river water and which may have similar resistance to drinking-water treatments, may be useful for estimating the level of treatment attained when large volumes of water (1000 L or greater) are sampled. [TOP OF PAGE]

  91. The use of bacteriophages of Bacteroides fragilis as indicators of the efficiency of virucidal products. Pinto, R.M., Abad, F.X., Roca, R.M., Riera, J.M., Bosch, A. (1991). FEMS Microbiol. Let. 82:61-66. The potential use of bacteriophage B40-8 of Bacteroides fragilis for the evaluation of the virucidal activity of antiseptics or disinfectants was investigated. The antiviral activity of two antiseptics and two disinfectants was evaluated according to a standard guideline. The effect of the virucidal agents was assessed on (i) viruses usually spread by direct contact with surfaces with contaminated secretions, i.e. herpes simplex virus 1 and 2, and vaccinia virus, and (ii) viruses transmitted by the fecal-oral route, i.e. hepatitis A virus, poliovirus, adenovirus and rotavirus. The survival of B40-8 always equalled or exceeded that of the animal viruses tested. Our data suggest the use of bacteriophage B40-8 to complement the information furnished by some standardized methods in ascertaining the antiviral activity of virucidal preparations. [TOP OF PAGE]

  92. ??? Popa, M., McKelvey, T., Hempel, J., Hendrix, R. (1991). J. Virol. 65:3227-??? [TOP OF PAGE]

  93. EFFECT OF ORGANIC MATTER ON VIRUS TRANSPORT IN UNSATURATED FLOW. Powelson, D.K., Simpson, J.R., Gerba, C.P. (1991). Appl. Environ. Microbiol. 57:2192-2196. Effect of organic matter on virus transport in unsaturated flow.The effects of natural humic material and sewage sludge organic matter (SSOM) derived from primary treated sewage sludge on virus transport by unsaturated flow through soil columns were evaluated. Bacteriophage MS-2 was applied to loamy fine sand columns 0.052 m in diameter and 1.05 m long. Virus concentrations in the influent and effluent were measured daily for 7 to 9 days. In the first experiment, virus transport through two fresh soil columns was compared with that through a column previously leached with more than four pore volumes (T) of well water. The soil water organic matter concentations in the leachate of the fresh soil declined with time. Relative virus concentrations (C/Co) from one fresh soil column reached 0.82 in 0.9 T and then declined to 0.51 by 2.1 T. The other fresh soil column reached and maintained a steady-state relative virus concentration [(C/Co)s] of 0.47 from 1.5 to 2.5 T. The leached column reached and maintained a (C/Co)s of 0.05. Concentrations measured at 0.2-, 0.4-, 0.8-, and 1.05-m depths indicated that most virus particles were removed in the surface 0.2 m. In the second experiment, one leached column was pretreated with SSOM derived from primary treated sewage sludge and the other leached column was untreated. SSOM concentrations declined with depth. A suspension of virus and SSOM in well water was applied to both columns. Although the (C/Co)s values were similar (0.41 for the pretreated column and 0.47 for the untreated column), breakthrough was delayed for the untreated column. Both natural humic material and sewage sludge-derived SSOM increased the unsaturated-flow transport of MS-2. [TOP OF PAGE]

  94. Roles of viral infection in organic particle flux. Proctor, L.M., Fuhrman, J.A. (1991). Mar. Ecol. Prog. Ser. 69:133-142. Lack of information on the fate of particulate-associated microorganisms prompted this investigation of viruses (including bacteriophage or phage) and phage-infected cells in sinking particles from sediment traps. Sediment trap material from 30 to 400 m collected from the north Pacific Ocean during the 'VERTEX' cruises in 1980 to 1982 was examined by transmission electron microscopy. Viruses were present in all of the sinking particles examined except for those from one sample, of highly degraded algal cells or small fecal pellets, from 400 m. Viruses in the sinking particles often appeared aggregated. From 0.7 to 3.7% of the bacteria in sinking particles contained mature phage; from these data and limited information from pure cultures, we estimate that 2 to 37% of the particulate-associated bacteria may be killed by viral lysis. Many eukaryotic cells were also apparently infected with viruses, but none (.ltoreq. 50 cells observed) of the cyanobacteria or 'Chlorella-like' cells appeared infected. Viral lysis of bacteria associated with sinking particles and free-living bacteria may be causally linked and may play a role in dissolved organic carbon production and the dynamics of sinking particles. Viral lysis may have major implications for understanding cycling of material and energy in the ocean. [TOP OF PAGE]

  95. The phage factor. Pullen, K.I., Dadson, P. (1991). Australian Journal of Medical Laboratory Science 12:44-47. Bacteria are host to a special group of viruses called bacteriophage (phage). Bacteria that are infected with phage are frequently isolated in the clinical laboratory. Phage become noticeable to the eye by the formation of plaques, a clear zone of lysis in the opaque film of bacterial growth. Bacteria that are infected with phage may pose a problem for those laboratories using Vitek sensitivity cards. It was found that the presence of phage may have the effect of lysing all bacteria in the card thus giving a result as "insufficient growth in positive control" or increasing the time a card takes to finalise. Phage infected bacteria may take a longer time to reach the predetermined threshold to turbidity in the positive control well because of bacterial lysis. Similarly in wells containing antibiotics, bacteria may be lysed, thus imitiating a more sensitive strain of bacteria. The calculated minimum inhibitory concentrations (MIC's) may be lowered and the interpretative cell of an antibiotic may be changed from resistant to sensitive. [TOP OF PAGE]

  96. The virus that eats bacteria. Radetsky, P. (1991). pp. 74-88. In AnonymousThe Invisible Invaders: The Story of the Emerging Age of Viruses. Little Brown & Company, Boston. [TOP OF PAGE]

  97. Preliminary investigation of suitable bacteria strains for the detection of bacteriophages in environmental polluted surface waters. REALI, D., ROSATI, S., PINTO, B., IAVARONE, M.R. (1991). ZENTRALBLATT FUR HYGIENE UND UMWELTMEDIZIN 192:248-257. Different host-specific bacteriophages were monitored in several water systems together with the usual faecal contamination indicator bacteria (thermotolerant coliforms). The host bacteria used for the plaque assay were E. coli K12, E. coli K12 Hfr, E. coli CHfr and S. typhimurium LT2F+. S. typhimurium LT2F+ showed significantly lower phage counts than the three E. coli strains. The phages specific for E. coli K12 (somatic phages) were in high correlation (r = 0.86, r = 0.91; P less than 0.001) with other coliphages, but not with phages specific for S. typ. LT2F+ (r = 0.33; P less than 0.05). There was an high degree of correlation among phages of E. coli K12 Hfr, E. coli C Hfr and S. typhimurium LT2F+ (pilus F-carrying bacteria) (r = 0.96, r = 0.73, r = 0.75; P less than 0.001). Good correlation was seen between faecal coliforms and male-specific phages but not among faecal coliforms and E. coli K12-specific phages (r = 0.30; P less than 0.05). The relative suitability of host strains when using phages in the evaluation of faecal and viral pollution of aquatic environments is discussed. [TOP OF PAGE]

  98. ON THE USE OF PHAGES AS INDICATORS OF FECAL POLLUTION. REALI, D., ROSATI, S., PINTO, B., IAVARONE, M.R. (1991). Igiene Moderna 95:820-834. On the use of phages as indicators of fecal pollution.The presence of bacteriophages in a variety of water systems was monitored in conjunction with indicator bacteria (thermotolerant coliforms). The host bacteria used for the plaque assay were Escherichia coli K12, E. coli K12 Hfr, E. coli C Hfr, Salmonella typhimurium LT2F+. There was a high degree of correlation between the levels of E. coli K12-, E. coli K12 Hfr-, and E. coli C Hfr phages; the degree of correlation between E. coli K12-phages and S. typhimurium LT2F+ phages was lower (r = 0.33, P < 0.05). Male-specific phages showed good correlation among each other and with levels of fecal coliforms, but phages infecting E. coli K12 and fecal coliforms were poorly correlated (r = 0.30, P < 0.05). The choice of one host bacteria over another to enumerate phages as indicators of fecal and viral pollution in environmental water systems is discussed. [TOP OF PAGE]

  99. Viruses distinguish symbiotic Chlorella spp. of Paramecium bursaria. Reisser, W., Burbank, D.E., Meints, R.H., Becker, B., Van Etten, J.L. (1991). Endocytobiosis and Cell Res. 7:245-251. [TOP OF PAGE]

  100. Use of Salmonella typhimurium WG49 to enumerate male-specific coliphages in an estuary and watershed subject to nonpoing pollution. Rhodes, M.W., Kator, H.I. (1991). Water Res. 25:1315-1324. The occurrence of male-specific RNA (FRNA) coliphages, proposed as indicators of enteric viruses, was determined in an estuary subject to nonpoint pollution that included fecal inputs from livestock. A host originally developed for detecting FRNA phages in sewage was applied to water and sediment samples. Phages were enumerated using the host Salmonella typhimurium WG49 containing an Escherichia coli plasmid coding for sex pili, and the female parent strain WG45. FRNA phages and fecal coliforms were enumerated in samples collected seasonally from an estuary and associated feeder streams and densities related to selected environmental parameters. Mean phage densities enumerated on WG49 ranged from < 1 to 50 100 ml-1 water and < 13 to 7200 100 g-1 dry sediment. Examination of 300 phages from estuarine and freshwater samples showed that .gtoreq. 99% were RNase-resistant, .gtoreq. 94% were lytic to the female parent salmonella strain (WG45), .ltoreq. 9% were lytic to male E. coli C3000, and none were lytic to female E. coli C. RNase resistant phages lytic to both salmonella strains were noncontractile flexible tailed phages and those lytic to male salmonella or E. coli hosts were filamentous phages. Electron micrographs of the only RNase-sensitive phage recovered that plaqued only male hosts showed cubic phage particles adsorbed to sex pili. Parallel enumerations of environmental samples on WG45 and WG49 yielded equal or greater phage densities on the former host. Purified phages from these samples were lytic to certain slamonella serovars recovered from the environment but did not cross react with fecal coliform or heterotrophic bacteria isolated from the environment. Although the WG49 host was inappropriate to estuarine and freshwater samples examined because of interference by somatic phages, WG45 and WG49 should be examined as hosts for enumerating salmonella phages. Similarly, the public health significance of somatic phages detected by these hosts should be determined. FRNA phages, with a single exception (1/187 sample), were not detected in a condemned shellfish growing area subject to nonpoint pollution. This observation questions the application of FRNA phages as indicators of fecal contamination in waters impacted by diffuse fecal inputs. [TOP OF PAGE]

  101. BACTERIOPHAGE SPECIFIC FOR THE CLAVIBACTER-SP ASSOCIATED WITH ANNUAL RYEGRASS TOXICITY. RILEY, I.T., Gooden, J.M. (1991). Letters in Applied Microbiology 12:158-160. [TOP OF PAGE]

  102. EFFECT OF THE LACTOPEROXIDASE SYSTEM ON BACTERIOPHAGE-RESISTANT MUTANTS OF LACTOCOCCI. Roginski, H., Hickey, M.W., LEGG, G.A. (1991). Australian Journal of Dairy Technology 46:31-35. Effect of the lactoperoxidase system on bacteriophage-resistant mutants of lactococci.Growth and acid production of selected lactococci and their phage-resistant derivatives (mutants) obtained in the 'factory-derived' selection procedure were studied in the presence of hydrogen peroxide and the lactoperoxidase system in milk. Some phage-resistant mutants were more susceptible to hydrogen peroxide and the lactoperoxidase system than their parent organisms. Growth studies with the phage-resistant mutant of Lactococcus lactis ssp. lactis ML8, under conditions of continuous supply of oxygen to sterile milk, showed that the lactoperoxidase system reduced biomass and acid production by more than 90%. The ratio of NADH oxidase to NADH peroxidase in L. lactis ssp. lactis ML8 was lower than in its phage-resistant mutant which may partly explain the mutant's higher sensitivity to the lactoperoxidase system. Routine screening of the 'factory derived' phage-resistant mutants to eliminate organisms sensitive to hydrogen peroxide and the lactoperoxidase system could enhance the level of protection against unpredicted starter failure in cheese manufacture. [TOP OF PAGE]

  103. Isolation and characterization of a coliphage specific for Escherichia coli O157:H7. Ronner, A.B., Cliver, D.O. (1991). J. Food Prot. 53:944-947. [TOP OF PAGE]

  104. The combined use of specific phages and antibiotics in different infectious allergoses. Sakandelidze, V.M. (1991). Vrach. Delo 3:60-63. [TOP OF PAGE]

  105. Phytophage effects on primary production, nutrient turnover, and litter decomposition of young Douglas-fir in western Oregon. Schowalter, T.D., Sabin, T.E., Stafford, S.G. (1991). Forest Ecology and Management 42:229-243. [TOP OF PAGE]

  106. Induction and partial purification of bacteriophages from Desulfovibrio vulgaris (Hildenborough) and Desulfovibrio deslfuricans ATCC 13541. Seyedirachti, S., Wood, C., Akagi, J.M. (1991). J. Gen. Microbiol. 137:1545-1549. [TOP OF PAGE]

  107. COMPOSITION AND PHAGE BINDING CAPACITY OF CELL WALLS ISOLATED FROM LACTOCOCCUS-LACTIS-SSP-CREMORIS SK110 AND SK112. SIJTSMA, L., HELLINGWERF, K.J., Wouters, J.T.M. (1991). Netherlands Milk and Dairy Journal 45:81-96. Composition and phage binding capacity of cell walls isolated from Lactococcus lactis ssp. cremoris SK110 and SK112.Cell walls were prepared from the phage-resistant (Lactococcus lactis subsp. cremoris SK110 and its phage-sensitive variant SK112. The peptidoglycan of the two strains contained MurNAc: GlcNAc:Glu:Lys:Asp:Ala at a molecular ratio of approximately 1:1:1:1:1:2. No teichoic acid was detected; instead a polysaccharide that consisted of rhamnose, glucose, galactose and glucosamine or its acetylated form (N-acetylglucosamine) was present. No significant differences in peptidoglycan composition were observed between the two strains. With respect to the additional polymer(s), cell walls from SK110 contained a higher amount of galactose and a lower amount of (N-acetyl)glucosamine as compared to SK112. Cell walls of both strains were able to inactivate phage sk11G. Extraction of the cell walls with dilute alkali, acid at low temperature or sodium dodecyl sulfate did not reduce the phage-inactivation ability. Heat treatment of walls at low pH, oxidation with sodium periodate, or solubilization of the walls with mutanolysin or lysozyme reduced this capacity remarkably. [TOP OF PAGE]

  108. VIRUS-LIKE PARTICLES IN BACTERIA SYMBIOTIC IN BIVALVE GILLS. Southward, E.C., Southward, A.J. (1991). Journal of the Marine Biological Association of the United Kingdom 71:37-46. Virus-like particles in bacteria symbiotic in bivalve gills.Thyasira gouldi, an arctic bivalve mollusc of the family Thyasiridae, has symbiotic, probably chemoautotrophic, bacteria living in its gills. In specimens collected from Loch Etive in Scotland in 1989, after local population had undergone an unexplained decline, the gill bacteria contained numerous virus-like particles 60 nm in diameter. The bacteria are not lysed by the virus, and the particles are not present outside the bacteria except in phagocytic vacuoles of the gill cells where the bacteria have been digested, leaving the virus particles unchanged. Similar particles have been discovered in bacterial symbionts of Thyasira flexuosa, but in much smaller numbers. [TOP OF PAGE]

  109. Virus ecology - reply. Suttle, C.A., Chan, A.M., Cottrell, M.T. (1991). Nature 351:612-613. [TOP OF PAGE]

  110. Use of ultrafiltration to isolate viruses from seawater which are pathogens to marine phytoplankton. Suttle, C.A., Chan, A.M., Cottrell, M.T. (1991). Appl. Environ. Microbiol. 57:721-726. Viruses may be major structuring elements of phytoplankton communities, and hence important regulators of nutrient and energy flux in aquatic environments. In order to ascertain if viruses are potentially important in dictating phytoplankton community structure, it is essential to determine the extent to which representative phytoplankton taxa are susceptible to viral infection. We used a spiral ultrafiltration cartridge (30,000 MW cutoff) to concentrate viruses from seawater at efficiencies approaching 100 %. Natural virus communities were concentrated from stations in the Gulf of Mexico, a barrier island pass and a hypersaline lagoon (Laguna Madre), and added to cultures of potential phytoplankton hosts. By following changes in in-vivo fluorescence over time it was possible to isolate several viruses that were pathogens to a variety of marine phytoplankton, including a prasinophyte (Micromonas pusilla), a pennate diatom (likely Navicula sp.), a centric diatom (of unknown taxa), and a chroococcoid cyanobacterium (Synechococcus sp.). As well, we observed changes in fluorescence in cultures of a cryptophyte (Rhodomonas sp.) and a chlorophyte (Nannochloropsis oculata) which were consistent with the presence of viral pathogens. Although pathogens were isolated from all stations, all the pathogens were not isolated from every station. Filterability studies on the viruses infecting Micromonas and Navicula showed that the viruses were consistently infective after filtration through polycarbonate and glass-fiber filters, but were affected by most other filter types. Establishment of phytoplankton/pathogen systems will be important in elucidating the affect that viruses have on primary producers in aquatic systems. [TOP OF PAGE]

  111. The course of giardiavirus infection in the Giardia lamblia trophozoites. Tai, J.H., Wang, A.L., Ong, S.J., Lai, K.S., Lo, C., Wang, C.C. (1991). Experimental Parasitology 73:413-423. The subcellular distribution of Giardia lamblia virus RNA in infected G. lamblia trophozoites was examined by in situ hybridization using biotinylated DNA probe and riboprobe. In G. lamblia Portland I strain, which is chronically infected by G. lamblia viruses, the viral RNA was detected in the cytoplasm as well as in the twin nuclei. When riboprobe was used to examine the course of virus infection in WB strain, accumulation of viral RNA was detected only in the cytoplasm prior to the first 72 hr of infection. Using DNA probe, further accumulation of viral RNA in increasing number of cells occurred after the 72nd hr of infection, with the RNA found in both the cytoplasm and nuclei. Eventually, the cell nuclei showed damaged morphology that deteriorated rapidly toward the final stage of infection. These observations indicate that early phase of viral RNA replication may take place in the cytoplasm of infected G. lamblia, but the nuclei are also involved during the late phase of viral replication. [TOP OF PAGE]

  112. ENVIRONMENTAL CONDITIONS WHICH INFLUENCE MUCOID CONVERSION IN PSEUDOMONAS-AERUGINOSA PAO1. TERRY, J.M., PINA, S.E., MATTINGLY, S.J. (1991). Infect. Immun. 59:471-477. Environmental conditions which influence mucoid conversion in Pseudomonas aeruginosa PAO1.Growth and conversion to the mucoid phenotype by nonmucoid Pseudomonas aeruginosa PAO1 was studied in a chemostat system under conditions designed to reflect those likely to be present during chronic infection in the lung in cystic fibrosis patients. Mucoid variants were consistently isolated during continuous culture in the presence of 0.3 M NaCl or 5 or 10% glycerol. Mucoid subpopulations were also detected under conditions of carbon, nitrogen, or phosphate limitation. During carbon or nitrogen limitation, mucoid conversion was dependent upon the choice of substrate. Phosphate-limited cultures exhibited an inverse relationship between culture growth rate and number of mucoid organisms detected. Mucoid variants were not detected when dilution rates (D) exceeded 0.173 h-1. Conversely, at a D of 0.044 h-1, 40% of the population expressed the mucoid phenotype. Phosphorylcholine, a product of phospholipase C activity on the major lung surfactant phosphatidylcholine, was also used as a growth substrate in nutrient limitation studies. Under all conditions, growth of PAO1 supplied with phosphorylcholine resulted in isolation of mucoid variants, indicating that the lung may provide at least one nutrient source conducive to mucoid conversion. Continuous culture also resulted in detection of a phage associated with strain PAO1. High titers of phage were present under all conditions, including those which yielded no mucoid organisms, suggesting that environmental conditions rather than the phage regulated the appearance of mucoid variants. [TOP OF PAGE]

  113. Parasite-Host Associations. Coexistance or Conflict? Toft, C.A., Aeschlimann, A., Bolis, L. (1991). Oxford University Press, New York.[TOP OF PAGE]

  114. CURRENT AND POSSIBLE ALTERNATE INDICATORS OF FECAL CONTAMINATION IN TROPICAL WATERS A SHORT REVIEW. Toranzos, G.A. (1991). Environmental Toxicology and Water Quality 6:121-130. Current and possible alternate indicators of fecal contamination in tropical waters: A short review.Bacteria that belong to the total and fecal coliform groups have been used for several decades as indicators of fecal pollution of waters and other systems. The prevailing idea behind this is that these two groups of bacteria cannot replicate outside the gastrointestinal tract of warm-blooded animals. Several studies conducted by this and other laboratories have indicated that these bacteria may be naturally present in certain areas of the world. Naturally occurring fecal coliforms (the genera Escherichia and Klebsiella) have been isolated from pristine sites and from sites where there was no apparent fecal contamination. All these results lead us to the conclusion that these groups of bacteria are not adequate indicators of fecal contamination in tropical areas of the world. Alternate indicators are being tested. This laboratory and others around the world are testing the adequacy of bacteriophages (more specifically, coliphages) for this purpose. In Puerto Rico coliphages have been detected only in areas known to be contaminated with domestic sewage, but not in pristine areas, although high levels of fecal coliforms can be detected at the latter sites. All these results suggest that coliphages may be used as indicators that more realistically demonstrate fecal contamination of waters in tropical areas of the world. In addition, newer techniques, although still in the trial stages, can be used to directly detect pathogens in the environment. Of all the techniques currently available, the polymerase chain reaction is the most promising for the direct detection of pathogens and therefore for the unequivocal evaluation of the biological quality of waters. [TOP OF PAGE]

  115. CHARACTERIZATION OF DNA OF VIRULENT BACTERIOPHAGE AND ITS INFECTIVITY TO HOST BACTERIA PSEUDOMONAS-SOLANACEARUM. Toyoda, H., Kakutani, K., IKEDA, S., Goto, S., TANAKA, H., Ouchi, S. (1991). Journal of Phytopathology (Berlin) 131:11-21. Characterization of DNA of virulent bacteriophage and its infectivity to host bacteria, Pseudomonas solanacearum.Virulent bacteriophage PK-101 was isolated from soil infested with strain K-101 of Pseudomonas solanacearum and nucleic acid was prepared from the phages. Some chemical properties of phage nucleic acid and its infectivities to various strains of P. solanacearum were examined in the present study. By digestion with restriction endonucleases, phage nucleic acid was shown to be linear duplex DNA approximately 35 kb long. Restriction fragment length polymorphism was observed when electrophoresis patterns of enzyme-digested PK-101 DNA were compared with those of DNA prepared from different phage isolates. Transfection of host strains by PK-101 DNA was carried out, and it was infectious not only to host strain K-101, but also to other strains which were resistant to phage particles. Transfection efficiency was considerably enhanced by directly introducing phage DNA into bacterial cells by means of an electroporation. The electroporation technique was also effective to transform P. solanacearum with large-size plasmid DNA. [TOP OF PAGE]

  116. Identification of bacteria and their antibiotic susceptibility by the aid of luciferase genes carrying bacteriophage. Ulitzur, S., Suissa, M., Kuhn, J. (1991). Int. Marine Biotechnology Conf. (IMBC '91), Baltimore, MD (USA), 13-16 Oct 1991; PROGRAM AND ABSTRACTS. SECOND INTERNATIONAL MARINE BIOTECHNOLOGY CONFERENCE. The basic element of this test is a DNA fragment coding for all or part of the luminescence (lux) operon from luminous marine bacteria. Transient or stable transfer of the lux operon into phenotypically dark bacteria by transformation, conjugation or transduction results in a rapid emission of light. The susceptibility of antibiotics of the bacteria in question can be determined from the degree of inhibition of luminescence developed by the tested bacteria. Using this technology we were able to determine the presence of about 1000 bacteria of Salmonella per ml together with their antibiotic susceptibility in a procedure lasting 45 minutes. 98% of the most common Salmonella serotype showed luminescence after infection with the lux carrying bacteriophage FelixO-1 and only 3 out of 273 strains of various non Salmonella species emit light with this phage. [TOP OF PAGE]

  117. Bacteriophage typing of Staphylococcus aureus strains from fermented milk products and raw milk. Umoh, V.J., Adesiyun, A.A., Gomwalk, N.E. (1991). Tropical Veterinarian 9:131-138. Out of 147 S. aureus isolates from raw milk and fermented milk products, 77 (52.4%) were typable using human phage set. Thirty-two were typable at RTD, 38 at 100 times RTD, 7 weak lysis and 70 untypable strains. One hundred and ten were tested using bovine phage set of 7 phages, 43 (39.1%) were typable, 9 at RTD, 25 at 100 &X RTD, 9 weak lysis and 67 untypable. The human page set typed significantly higher number (P lt 0.05) of isolates from fermented milk (63.0%) while the bovine phage set typed more from raw milk (44.4%). Most of the 70 strongly typable strains were lysed by human group III phages while most of the 34 typable strains using bovine phage set belonged to group IV. About 50% of the isolates lysed by the 94/96 complex were resistant to penicillin, ampicillin and sulphafurazole and 2 (22.2%) produced enterotoxin A. Of the 4 isolates lysed by the 102/118 complex 2 were alpha haemolytic and 3 produced enterotoxin A. [TOP OF PAGE]

  118. Phycodnaviridae. Van Etten, J.L. (1991). pp. 137-139. In In Francki, R.I.B., Fauguet, C.M., Knudson, D.L., and Brown, F. (eds.), Classification and Nomenclature of Viruses: Archives of Virology Supplement. Springer-Verlag, Vienna. [TOP OF PAGE]

  119. Viruses and virus-like particles of eukaryotic algae. Van Etten, J.L., Lane, L.C., Meints, R.H. (1991). Microbiol. Rev. 44:586-620. Until recently there was little interest or information on viruses and viruslike particles of eukaryotic algae. However, this situation is changing. In the past decade many large double-stranded DNA-containing viruses that infect two culturable, unicellular, eukaryotic green algae have been discovered. These viruses can be produced in large quantities, assayed by plaque formation, and analyzed by standard bacteriophage techniques. The viruses are structurally similar to animal iridoviruses, their genomes are similar to but larger (greater than 300 kbp) than that of poxviruses, and their infection process resembles that of bacteriophages. Some of the viruses have DNAs with low levels of methylated bases, whereas others have DNAs with high concentrations of 5-methylcytosine and N6-methyladenine. Virus-encoded DNA methyltransferases are associated with the methylation and are accompanied by virus-encoded DNA site-specific (restriction) endonucleases. Some of these enzymes have sequence specificities identical to those of known bacterial enzymes, and others have previously unrecognized specificities. A separate rod-shaped RNA-containing algal virus has structural and nucleotide sequence affinities to higher plant viruses. Quite recently, viruses have been associated with rapid changes in marine algal populations. In the next decade we envision the discovery of new algal viruses, clarification of their role in various ecosystems, discovery of commercially useful genes in these viruses, and exploitation of algal virus genetic elements in plant and algal biotechnology. [TOP OF PAGE]

  120. Unicellular plants also have large dsDNA viruses. Van Etten, J.L., Lane, L.C., Meints, R.H. (1991). Seminars Virol. 2:71-77. [TOP OF PAGE]

  121. Viruses of the protozoa. Wang, A.L., Wang, C.C. (1991). Ann. Rev. Microbiol. 45:251-263. [TOP OF PAGE]

  122. Genome structure and RNA polymerase activity in Leishmania virus. Widmer, C., Patterson, J.L. (1991). J. Virol. 65:4211-4215. [TOP OF PAGE]

  123. Isolation and characteristic of new phages from a serine- producing Escherishia coli K-12. Wu, W.W., Tanaka, K., Yoshinaga, K., Kato, F., Kanda, K., Murata, A. (1991). Journal of Fermentation and Bioengineering 71:293-297. Two lytic phages, designated S1 and S2, were isolated from culture lysates of a genetically modified serine-producing Escherichia coli K-12. Both phages were highly species- specific for E. coli. S1 was specific for strains of K-12, while S2 attacked strains B and C in addition to K-12 strains. S1 had an icosahedral head 75 nm in diameter and a contractile tail 150 nm long. S2 had an icosahedral head 60 nm in diameter and a noncontractile tail 160 nm long. They were serologically unrelated. Their serotypes were different from those of the other E. coli phages. The latent period and burst size were 28 min. and 450, respectively, for S1, and 15 min and 100, respectively, for S2. The phages contained double-stranded DNA with four normal bases. The G + C contents were about 31% for S1 DNA and about 37% for S2 DNA. Restriction patterns of their DNAs were different from each other. The genome sizes were 52 kbp for S1 and 49 kbp for S2. No homology was observed between their genomes. Furthermore, the structural proteins of the two phages also differed. We conclude that phages S1 and S2, differing from each other, could be new phages for E. coli. [TOP OF PAGE]

  124. Inactivation of bacteriophage MS-2 and poliovirus in copper and plastic domestic water pipes. Yahya, M.T., Straub, T.M., Gerba, C.P., Margolin, A.B. (1991). Int'l. J. Environ. Hlth. Res. 1:76-86. [TOP OF PAGE]

  125. Screening of natural waters for viruses which infect Chlorella cells. Yamada, T., Higashiyama, T., Fukuda, T. (1991). Appl. Environ. Microbiol. 57:3433-3437. [TOP OF PAGE]

  126. A quantifiable phenotype of viral propagation. Yin, J. (1991). Biochim. Biophys. Acta 174:1009-1014. A system has been identified where a virus, replicating continuously on its host, displays a distinct and quantifiable phenotype, and thereby continuously reports on the state of the virus-host relationship. When bacteriophage T7 is plated out with its host, Escherichia coli, it establishes a constant-velocity infection wave, which is driven by an autocatalytic reaction- diffusion mechanism. The velocity—which is easily measured—continuously reflects the infection environment. The simplicity of the system extends to the investigator an unprecedented ability to monitor and control a viral infection process. [TOP OF PAGE]

  127. Pathomorphological evaluation of therapeutic effect of mycophages in tuberculosis. Zemskova, Z.S., Dorozhkova, I.R. (1991). Probl. Tuberk. 11:63-66. [TOP OF PAGE]

  128. THE COMPARATIVE STUDY OF THE LEVELS OF VIRUSES AND INDICATOR BACTERIA IN SOURCE WATER AND TAP WATER. Zhang, C.-Y., Wang, Z.-Q. (1991). Virologica Sinica 6:65-70. The comparative study of the levels of viruses and indicator bacteria in source water and tap water.The presence of any pathogenic viruses in tap water has always been considered a potential public health concern. This study reports the presence levels of viruses and indicator bacteria in the water body of East Lake and treated tap water. During a year's work, indicator bacteria and viral analysis were performed on each sample. We found that total plate count is 2 .times. 103-6.8 .times. 108/L, total coliforms is 130-5.5 .times. 104/L, fecal coliforms is 10-960/L, coliphage is 0.35-65 CFU/L, average is 26.48 CFU/L, enteroviruses is 0-167.5 PFU/L, average is 14.31 PFU/L for the source water of East Lake; we also found that total plate count is 41-500/L, total coliforms is 0-4/L, coliphage is 0-13.6 CFU/L, average is 2.48 CFU/L, enteroviruses is 0-78 PFU/L, average is 6.46 PFU/L for the tap water from the source water of East Lake. Indicator bacteria (standard plate count bacteria, total coliform and fecal coliform), coliphasge and enteroviruses reduction average 97.95-99.99%, 90.63% and 53.18% respectively, for the complete treatment process involving prechlorination, coagulation-sedimentation, sand filtration, and final chlorination. The complete water treatment process was more effective in the reduction of turbitity, coliform, fecal coliform, standard plate count bacteria, and coliphage than enteric viruses. The isolation of human enteric viruses in tap water is not a condemnation of conventional tap water treatment, but an indication that water quality criteria currently accepted to ensure production of microbially safe water do not necessarily ensure the absence of enteric viruses. It is necessary to establish virus standard for tap water, and search for more suitable indicators of the presence of viruses in water. [TOP OF PAGE]

  129. Lysogeny of methicillin-resistant Staphylococcus aureus and the role of prophages in transfer of conjugative and non-conjugative plasmids. Zueva, V.S., Nesterenko, L.N., Dmitrenko, O.A., Akatov, A.K. (1991). JOURNAL OF CHEMOTHERAPY 3:279-282. The lysogenicity of 49 strains of methicillin-resistant S. aureus (MRSA) isolated in Moscow clinics in the 1970s and '80s was studied by the method of mitomycin C induction. It was found that one strain had phage of serogroup B, 33 strains had serogroup F phages and 15 strains had phages of both serogroups. In the course of genetic crossing on nitrocellulose filters it was demonstrated that serogroups B and F prophages contained in recipient cells 1) increase the frequency of transfer of conjugative plasmid pG873 and 2) mobilize transfer of non-conjugative plasmids pE994 and rms7. [TOP OF PAGE]

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