Bacteriophage Ecology Group
Reference Abstracts (1993)
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. Lysogeny and lysotypes of Malaysian strains of Pseudomonas solanacearum. Abdullah, H., Hartman, G.L., Hayward, A.C. (1993). ACIAR Proceedings 316-319. [TOP OF PAGE]

  2. The isolation of T-even phages (feces -?-> P.C./PC --> gamma --> T2; Sewage -?-> T4/T6). Abedon, S.T. (1993). T4 News (Feb 17). It may never prove possible to identify, with high confidence, the time, place, and source material for the original isolation of phages T2, T4, and T6. Nevertheless, a better understanding of where T-even phages came from has historical significance and is even of scientific consequence to those of us interested in the ecology of these organisms. Gathering clues for the discovery of a likely candidate for the original isolation of phage T2 was the more difficult task. For phages T4 and T6 this search was much less problematic and is presented first. I conclude with a conjecture on the history of free tryptophan (trp) adsorption cofactor dependence in these phages. Full text is also available. [TOP OF PAGE]

  3. Conjugative mobilization of a heat-sensitive phage resistance (Hsp positive) plasmid between Lactococcus lactis ssp. lactis strains. Akcelik, M. (1993). Turkish Journal of Biology 17:155-161. A self-transmissible 30.0 Kb plasmid encoding lactose fermentation ability (Lac+) from Lactococcus lactis subsp. lactis KO8 was identified. The 26.1 Kb nonconjugative Hsp+ plasmid was mobilized by this Lac+ plasmid after transformation to a Lac+ derivative (KMI) of strain KO8. Lac+, Hsp- and Lac+, Hsp+ transconjugants were obtained after filter matings of KMI and plasmid free recipient L. lactis subsp. lactis P81-1. Hsp+ phenotype in Lac+ transconjugants were detected at the rate of 77 per cent. All Lac+, Hsp+ transconjugants showed two plasmid profiles with the molecular sizes of 30.0 Kb and 21.8 Kb. The data suggests that 26.1 Kb Hsp+ plasmid has lost its 4.3 Kb region during cointegration process. [TOP OF PAGE]

  4. Comparative inhibitory action of 4 standard bacteriophages on the larvicidal activity of certain mosquito pathogenic bacteria against Culex pipiens larvae. Ali, S.M., Saleh, M.B., Merdan, A.I. (1993). Journal of the Egyptian Society of Parasitology 23:341-348. Four bacteriophage (CP-51, CP-54, Yousten-4 and Yousten-14) were assayed against 7 entemopathogenic bacterial strains. The two CP ones, indicating variability of the host range of the tested phages which was suggested to be related to the environmental characteristics of the tested strains. On testing the susceptibility of 5 bacterial strains to the phage Yousten-4 at different cultural ages, a correlation was found between incubation time and level of bacterial susceptibility to the tested phage. This observation was explained to be due to the number of vegetative cells and/or sporulation. [TOP OF PAGE]

  5. Isolation, purification and ultrastructure of bacteriophages from natural mosquito breeding places in Egypt. Ali, S.M., Saleh, M.B., Merdan, A.I. (1993). Journal of the Egyptian Society of Parasitology 23:431-435. Two bacteriophages were isolated from field collected samples representing two different mosquito breeding places. The phage AB- 1 (isolated from Abheit village, Faiyoum Governorate "seepage water") and the phage GA-2 (isolated from El-Gabal El-Asfer Qualyobia Governorate "sewage drain water") were purified. Both bacteriophages were ultrastructurally described with respect to their morphology, dimensions, phases of bacterial attack and lysogeny. No major differences were observed between both isolated phages in relation to specificity, however; they were isolated from two different types of breeding places and two different geographic areas as well. This study may assume a wide host range of the isolated phages and reflect how bacterial insecticides used for mosquito larval control could be inhibited by such bacteriophage. [TOP OF PAGE]

  6. Effect of bacteriophage lysogeny on the efficacy of two bacterial larvicide formulations under field conditions. Ali, S.M. (1993). Journal of the Egyptian Society of Parasitology 23:305-312. Two types of man-made ditches were selected for carrying out this experiment; one polluted with nitrogenous matters (sewage water) and second filled with accumulated irrigated clear non- chlorinated water. No phages were detected in samples collected from both types of ditches. However, phage(s) specific to only B. sphaericus was (were) detected after spraying the two types with both B. thuringiensis H-14 and B. sphaericus commercial formulations. The detection of phage(s) was observed after 3 days post-spraying in the polluted ditch and after one week in the non-polluted one. This observation was explained by a possible transduction of naturally existed phage(s) on other spore forming bacteria to the sprayed B. sphaericus only, as its commercial formulation is based on spores which germinate to produce vegetative cell, while B. thuringiensis H-14 contains only the O-endotoxin as active ingredient, and also due to the increase of the number of bacteria in the sprayed ditches due to the recycling of B. sphaericus in the aquatic breeding places. [TOP OF PAGE]

  7. A field survey of bacteriophage contamination of mosquito breeding places, inhibiting bacterial insecticide. Ali, S.M., Saleh, M.B., Merdan, A.I. (1993). Journal of the Egyptian Society of Parasitology 23:389-397. Twelve geographically different mosquito breeding places were described and sampled for the detection of naturally existed bacteriophage viruses which could transduct and lysate 5 entomopathogenic bacteria. The surveyed places are classified into seepage, sewage, and irrigation breeding water. Bacterial free filtrates of the collected samples were assayed against the tested bacteria in vitro and against 3rd instar Culex pipiens larvae as well. Nine out of the twelve places could demonstrate the presence of phages. Bacillus thuringiensis H-14 was foud susceptible to phage(s) present in polluted and irrigated water of 5 location, while, B. thuringiensis Berliner was susceptible to only a specific phage of one breeding place (polluted, sewage water). With regard to Bacillus sphaericus strains 1593 and 114, bacteriophages of sewage and irrigated water could lysate them and these phages are characterized by being of a moderate host range, except one phage which showed high specificity with strain 114 and was detected in a polluted sewage water sample collected from Dakahliya Governorate. The detected phages proved to lysate both B. thuringiensis H-14 and B. sphaericus 1593 on their larvicidal action through a series of bioassay experiment, almost all results indicate the presence of a significant inhibitory activity. [TOP OF PAGE]

  8. A simple, rapid and sensitive presence/absence detection test for bacteriophage in drinking water. Armon, R., Kott, Y. (1993). J. Appl. Bacteriol. 74:490-496. A rapid, simple and sensitive direct bacteriophage presence detection method for 500 ml drinking water samples has been developed. The method includes a glass device consisting of a jar containing the water sample and an immersible probe filled with solidified soft agar containing bacterial host cells. Host bacteria in logarithmic phase were added to the experimental volume and the probe was submerged. The entire device was incubated in a water bath at 36 degree C. Plaques of somatic bacteriophage infecting Escherichia coli strain CN-13, could be detected within 3 h. Male-specific bacteriophages infecting E. coli F+ amp were detected within 6 h. Bacteriophage infecting the anaerobe Bacteroides fragilis subsp. fragilis HSP40 were detected after 8 h. Application of this device and the associated technique, enabled a one-step detection of 1 pfu of E. coli or Bact. fragilis specific bacteriophage in 500 ml drinking water samples. [TOP OF PAGE]

  9. Successful transient introduction of Leishmania RNA virus into a virally infected and an uninfected strain of Leishmania. Armstrong, T.C., Keenan, M.C., Widmer, G., Patterson, J.L. (1993). Proc. Natl. Acad. Sci. USA 90:1736-1740. Viruses of Leishmania have recently been identified and characterized. These viruses are consistently double-stranded RNA viruses of approximately 5 kb. To date, they have not been reported to exist outside their protozoan host, nor have they been shown to be infectious. We report here the ability to transiently transfer these viruses to two strains of Leishmania, one previously infected and one that did not previously carry a virus. A PCR-based assay was used to detect viral negative-stranded RNA. Input RNA was ruled out as the source of template because a replication-incompetent (UV inactivated) virus was not detectable after transfer into Leishmania. [TOP OF PAGE]

  10. Biophysical characterization of Vibrio El Tor typing phage e5. Basu, R., Ghosh, A.N., Dasgupta, S., Ghosh, A. (1993). FEMS Microbiol. Let. 80:9-15. Vibrio cholerae typing phage e5, which can lyse only the El Tor strains of V. cholerae, was characterized. The phage had a polyhedral head 51 nm in diameter and a short tail 13 nm in length. It contained 13 structural polypeptides, with the molecular mass of the major component being 50 kDa. Phage chromosome comprised a 38.5-kb linear double-stranded DNA molecule with unique termini, as determined by restriction fragment analysis and electron microscopy, and had a G+C content of 35.5%. A physical map was constructed with the restriction endonucleases HaeII and HpaII. Adsorption of the phage to its host followed a biphasic kinetics and its intracellular growth was characterized by a latent period of 15 min and a burst size of 100 particles per infected cell. The phage was found to be moderately thermotolerant. [TOP OF PAGE]

  11. Ultrastructural studies on a chlorella virus from Germany. Becker, B., Lesemann, D.E., Reisser, W. (1993). Arch. Virol. 130:145-155. [TOP OF PAGE]

  12. Growth characteristics of lactococcal phages isolated from the dairy sources in India. Bhimani, R.S., Freitas, Y.M. (1993). Journal of Dairy Science 76:3338-3349. Host-phage interactions of four lactococcal phages, FRC1, FRC2, FRC3, and FRC4, were studied. Adsorption was maximum at 30 degree C and pH of 7.2 to 7.6 after 10 min. Optimal growth temperatures of the host and phage were 37 degree C. Plaques appeared after 4 h at 30 degree C and reached a plateau after 12 h. Thermal death points of the phages were in the range of 65 to 80 degree C. In M17 broth and skim milk, thermal death points were 5 to 10 degree C higher. Phages were stable at 4 degree C for 2 mo and 14 to 16 mo at -20 degree C. Phages survived 4 to 5 d under dry conditions and were sensitive to ether, ethanol, formaldehyde, iodine, potassium permanganate, phenol, phenyl, and SDS; KH-2PO-4, K-2BPO-4, MgSO-4, NaCl, KCl, CaCl-2, Na-2SO-4, K-2SO-4, and CH-3CO-ONa promoted adsorption and phagemediated lysis of host cells. The latent period, eclipse phase, rise period, and burst sizes of these phages were 40 to 45 min, 22 to 32 min, 15 to 20 min, and 70 to 150 min, respectively. Burst size decreased 15 to 37% at 33 degree C and 50 to 64% at 37 degree C. Lactococcal hosts challenged with homologous phages showed greatly decreased culture turbidity and lowered acid production (42 to 61%). [TOP OF PAGE]

  13. Palmer LTER: aquatic virus abundances neaer the Antarctic Peninsula. Bird, D.F., Maranger, R. (1993). Antarct. J. U. S. 28:234-235. [TOP OF PAGE]

  14. Viruses, bacterplankton, and phytoplankton in the southeastern Gulf of Mexico: distribution and contribution to oceanic DNA pools. Boehme, J., et al. (1993). Mar. Ecol. Prog. Ser. 97:1-10. [TOP OF PAGE]

  15. Native marine bacteriophages. Børsheim, K.Y. (1993). FEMS Microbiol. Ecol. 102:141-159. [TOP OF PAGE]

  16. Viral impact on microbial communities. Bratbak, G., Heldal, M., Naess, A., Roeggen, T. (1993). pp. 299-302. In In Guerrero, R. and Pedros-Alio, C. (eds.), Trends in Microbial Ecology. Spanish Society for Microbiology, Barcelona. [TOP OF PAGE]

  17. Total count of viruses in aquatic environments. Bratbak, G., Heldal, M. (1993). pp. 135-138. In In Kemp, P.F. (ed.), Handbook of Methods in Aquatic Microbial Ecology. CRC Press, Inc., Boca Raton,Fla. [TOP OF PAGE]

  18. Viral mortality of the marine alga Emiliana huxleyi (Haptophyceae) and termination of algal blooms. Bratbak, G., Egge, J.K., Heldal, M. (1993). Mar. Ecol. Prog. Ser. 93:39-48. [TOP OF PAGE]

  19. Experimental molecular evolution of bacteriophage T7. Bull, J.J., Cunningham, C.W., Molineux, I.J., Badgett, M.R., Hills, D.M. (1993). Evolution 47:993-1007. We present an analysis of molecular evolution in a laboratory- generated phylogeny of the bacteriophage T7, a virus of 40 kilo- base pairs of double-stranded DNA. The known biology of T7 is used in concert with observed changes in restriction sites and in DNA sequences to produce a model of restriction-site convergence and divergence in the experimental lineages. During laboratory propagation in the presence of a mutagen, the phage lineages changed an estimated 0.5% 1.5% in base pairs; most change appears to have been G fwdarw A or C fwdarw T, presumably because of the mutagen employed. Some classes of restriction-site losses can be explained adequately as simple outcomes of random processes, given the mutation rate and the bias in mutation spectrum. However, some other classes of sites appear to have undergone accelerated rates of loss, as though the losses were selectively favored. Overall, the wealth of knowledge available for T7 biology contributes only modestly to these explanations of restriction-site evolution, but rates of restriction-site gains remain poorly explained, perhaps requiring an even deeper understanding of T7 genetics than was employed here. Having measured these properties of molecular evolution, we programmed computer simulations with the parameter estimates and pseudo- replicated the empirical study, thereby providing a data base for statistical evaluation of phylogeny reconstruction methods. By these criteria, replicates of the experimental phylogeny would be correctly reconstructed over 97% of the time for the three methods tested, but the methods differed significantly both in their ability to recover the correct topology and in their ability to predict branch lengths. More generally, the study illustrates how analyses of experimental evolution in bacteriophage can be exploited to reveal relationships between the basics of molecular evolution and abstract models of evolutionary processes. [TOP OF PAGE]

  20. A novel antivirulence element in the temperate bacteriophage HK022. Carlson, N.G., Little, J.W. (1993). J. Bacteriol. 175:7541-7549. Lysogens of the temperate lambdoid phage HK022 are immune to superinfection by HK022. Superinfection immunity is conferred in part by the action of the HK022 CI repressor at the O.R operators. In this work, we have identified an additional regulatory element involved in immunity. This site, termed OFR (operator far right), is located just downstream of the cro gene, more than 250 nucleotides distant from OR. The behavior of phage containing a mutation in OFR suggests that the wild-type site functions as an antivirulence element. HK022 OFR- mutants were able to form turbid plaques indistinguishable from those of the wild type. However, they gave rise to virulent derivatives at a far higher frequency than the wild type (approximately 10(-5) for OFR- versus about 10(-9) for the wild type). This frequency was so high that cultures of HK022 OFR- lysogens were rapidly overgrown by virulent derivatives. Whereas virulent mutants arising from a wild-type OFR+ background contained mutations in both OR1 and OR2, virulent derivatives of the OFR- mutant phage contained a single mutation in either OR1 or OR2. We conclude that the wild-type OFR site functions to prevent single mutations in OR from conferring virulence. The mechanism by which OFR acts is not yet clear. Both CI and Cro bound to OFR and repressed a very weak rightward promoter (PFR). It is unlikely that repression of PFR by CI or Cro binding to OFR can account in full for the antivirulence phenotype conferred by this element, since PFR is such a weak promoter. Other models for the possible action of OFR are discussed. [TOP OF PAGE]

  21. Bacteriophages detection during storing potato. Castro, S., Romero, J., Fresno, J., Noval, C. (1993). Investigacion Agraria Produccion y Proteccion Vegetales 8:109-116. In the course of a routine screening program of Baraka potato samples from Palencia. destined to human consumption, showing symptoms of putrefaction, we have found lysis plates on bacterial cultures. Analysis were performed on material coming from two types of extractions. The first type came from the boundary between healthy and diseased tissue. The second one was from a deeper zone, corresponding to a medullar part with a slightly translucid aspect. Lysis plates were found only in colonies from superficial extractions. Bacteriophages were isolated using the NYGB medium, by the procedure of the NYGA double sandwich. We detected the presence of bacteriophage F.20-4, causing lysis on Erwinia carotovora sub. carotovora and F. 19-1, infecting Pseudomonas. The characterization of the phages was carried out using indicator bacterial strains. These were bacteria isolated from potatoes showing putrefaction and pathogenic strains from potato. Phages were analyzed under the electron microscope. [TOP OF PAGE]

  22. Genetic bottlenecks and population passages cause profound fitness differences in RNA viruses. Clarke, D.K., Duarte, E.A., Moya, A., Elena, S.F., Domingo, E., Holland, J. (1993). J. Virol. 67:222-228. Repeated clone-to-clone (genetic bottleneck) passages of an RNA phage and vesicular stomatitis virus have been shown previously to result in loss of fitness due to Muller's ratchet. We now demonstrate that Muller's ratchet also operates when genetic bottleneck passages are carried out at 37 rather than 32.degree.C. Thus, these fitness losses do not depend on growth of temperature-sensitive (ts) mutants at lowered temperatures. We also demonstrate that during repeated genetic bottleneck passages, accumulation of deleterious mutations does occur in a stepwise (ratchet-like) manner as originally proposed by Muller. One selected clone which had undergone significant loss of fitness after only 20 genetic bottleneck passages was passaged again in clone-to-clone series. Additional large losses of fitness were observed in five of nine independent bottleneck series; the relative fitnesses of the other four series remained close to the starting fitness. In sharp contrast, when the same selected clone was transferred 20 more times as large populations (105 to 106 PFU transferred at each passage), significant increases in fitness were observed in all eight passage series. Finally, we selected several clones which had undergone extreme losses of fitness during 20 bottleneck passages. When these low-fitness clones were passaged many times as large virus populations, they always regained very high relative fitness. We conclude that transfer of large populations of RNA viruses regularly selects those genomes within the quasispecies population which have the highest relative fitness, whereas bottleneck transfers have a high probability of leading to loss of fitness by random isolation of genomes carrying debilitating mutations. Both phenomena arise from, and underscore, the extreme mutability and variability of RNA viruses. [TOP OF PAGE]

  23. Spatial distribution of viruses, bacteria and chlorophyll a in neritic, oceanic and estuarine environments. Cochlan, W.P., Wikner, J., Steward, G.F., Smith, D.C., Azam, F. (1993). Mar. Ecol. Prog. Ser. 92:77-87. The spatial distribution of viruses was investigated in the coastal and oceanic waters of the Southern California Bight, USA, and the brackish waters of the Gulf of Bothnia, Sweden, using the direct harvesting technique and transmission electron microscopy. The vertical and horizontal distributions of viruses were examined in relation to bacterial abundance and chlorophyll a. Total virus abundances ranged from 0.3 to 52 times 10-9 l-1; higher concentrations of viruses were found in the upper 50 m of the water column and in coastal environments. Viruses with capsid diameters less than 60 nm dominated the virus community, were morphologically characterized as bacteriophages and were responsible for most of the observed spatial variability. Bacteria abundance alone explained 67% of the spatial variability in virus numbers, thereby suggesting that bacteria constituted the major host organisms for viruses in these physically diverse habitats. [TOP OF PAGE]

  24. Incidence of the bacterial contamination in the estuary of Ares-Betanzos (NW Spain). Combarro, M.P., Sueiro, R.A., Araujo, M., Pardo, F., Garrido, M.J. (1993). Microbiologia (Madrid) 9:14-27. The presence of bacterial indicators of fecal pollution and V. parahaemolyticus in the estuary of Ares-Betanzos (ria de Ares-Betanzos, NW of Spain) was investigated. Resistance patterns of coliform bacteria to eight antibacterial agents were also determined. In general, high numbers of indicator bacteria were found; for instance, heterotrophic bacteria ranged between 1.82 times 10-2 to 1.9 times 10-4 CFU/ml and up to 4.6 times 10-3/100 mi fecal coliforms in surface waters and 1.2 times 10-4/100 ml fecal streptococci in sediment could be found. Surface waters of sampling points 2 and 7, located at the inner part of the estuary, were more polluted than the corresponding ones in the mouth (sampling points, 1, 3, 4 and 9), whereas the sediment showed just the opposite distribution. An 88.5 % of isolated coliforms were resistant to one or more antibacterial agents. The MAR index points to urban wastewaters as the probable origin of pollution. The low incidence of V. parahaemolyticus and the lack of correlation with any of the fecal indicator bacteria determined, discard its use as indicative of fecal pollution in marine environments. [TOP OF PAGE]

  25. Computerized complex typing of Escherichia coli strains from different clinical materials. Czirok, E., Herpay, M.M.H. (1993). Acta Microbiologica Hungarica 40:217-237. A multivariate analysis of 3334 Escherichia coli strains originating from different clinical materials revealed that 50.2% of isolates belonged to the most common 12 (O1, O2, O4, O6, O7, O8, O15, O18, O45, O75, O78, O83) out of 133 serogroups. Haemolysin (Hly) production, mannose resistant haemagglutinating activity for human erythrocytes (MRHA) and colicinogenicity (Col) were recorded in 30, 30 and 36%, respectively. Antigens K1 and K5 were present in 11% and 6.6%, respectively. Association were found among certain serotypes and virulence markers (O1, H-, H7, K1, MRHA, Col; O2, H-, Kl, Col; O4, H-, H5, MRHA, Hly; O6, H-, H1, MRHA, Hly; O6, K5, MRHA, Col; O7, H-, H4, K1, MRHA, Col; O18ac, H7, K1, Col; O18ac, H-, K5, MRHA, Hly; O78, H-, Col (V-type); O83, H-, K1, Col). There were associations among clinical specimens, age of patients, nosocomial group of diseases, serogroups and virulence markers, too (cerebrospinal fluid-CSF-O7, O18ac, O45, O83-K1-newborn meningitis; O78-ColV-meningitis, sepsis, inflammations diseases of premature babies; CFS-O6, MRHA, Hly-adult-meningitis, sepsis, urinary tract infection-UTI-, pneumonia, other inflammatory diseases; blood-O2, O4, O6, O18ac, ONT, K5, MRHA, Hly-sepsis, UTI, hepatic diseases; urine-O1, O2, O4, O6, O18ac, O75, virulence markers fall to differ among upper and lower UTI; faeces-O1, O4, O6, O18ac, O78, virulence markers rare). Associations were also found among animal pathogenicity tests, specimens, serogroups and virulence factors: highly virulent group strains (i.e. LD50 below 10(6)) belonged to serogroups O2, O6, O18ac, possessed antigen K1 (less frequently the presence of MRHA, Hly, K5) and originated mainly from CSF. With mouse lung toxicity test correlations of serogroups (O4, O6, O18ac), antigen K5, MRHA, Hly and specimens (blood) were also shown. However, association was found between the lack of virulence factors and phage insensitivity and also between K5 positivity and sensitivity to phages 16, 17, there were no correlations between serogroups and phage patterns. On the basis of the above-described associations one can find correlations among virulence markers, serotype, and nosological group of diseases. Animal pathogenicity tests give additional data in understanding the pathomechanism of diseases. Correlations between phage patterns and serogroups reveal certain epidemiological relatedness and also virulence of strains. [TOP OF PAGE]

  26. Preliminary study of test methods to assess the virucidal activity of skin disinfectants using poliovirus and bacteriophages. Davies, J.G., Babb, J.R., Bradley, C.R., Ayliffe, G.A. (1993). Journal of Hospital Infection 25:125-131. [TOP OF PAGE]

  27. Lytic bacteriophages of Streptococcus mutans. Delisle, A.L., Rostkowski, C.A. (1993). Current Microbiology 27:163-167. Three phages of Streptococcus mutans were obtained and partially characterized. The three phages, designated M102, e10, and f1, were found to be strictly lytic, with host ranges restricted to only serotype c, e, and f strains of this species, respectively. Phage sensitivity was not correlated with the presence of plasmids, at least in host strains of serotypes c and e. Each phage produced clear plaques in a number of standard media, even in the presence of sucrose, indicating that the extracellular glucan polysaccharides (mutan) produced by the hosts from this substrate do not prevent phage adsorption and growth. The phages were similar in size and morphology, having icosahedral heads and long (283-287 nm), flexible, noncontractile tails. The genome of each phage was found to consist of linear, double-stranded DNA, 31-35 kb in length, with a base composition of 37-38% G + C. Restricting phage DNAs with four enzymes produced fragment patterns unique to each phage, but common bands between M102 and e10 and between e10 and f1 were produced by BamHI. Labeled e10 and M102 DNAs hybridized strongly with all three phage DNAs, indicating that they share some common sequences. The three phages appear to be more similar than expected and probably evolved from a common ancestor. [TOP OF PAGE]

  28. Direct electron microscopy study on the morphological diversity of bacteriophage populations in Lake Plusssee. Demuth, J., Neve, H., Witzel, K.-P. (1993). Appl. Environ. Microbiol. 59:3378-3384. Direct electron microscopy of bacteriophages adsorbed to a carbon film without prior enrichment by specific host strains or concentration by physical or chemical methods was used to study the morphological diversity of natural bacteriophage assemblages in a North German lake. All samples contained a mixture of morphologically different tailed viruses, which were regarded as bacteriophages. Most of them had isometric heads and tong noncontractile tails, belonging to morphotype B1 (Siphoviridae). In addition, members of morphotypes A1 (Myoviridae), B2 (Siphoviridae with elongated heads), and C1 (Podoviridae) were present in lower numbers. Only one cubic virus was detected, while no filamentous or pleomorphic phages were found. Up to 11 different phages per sample, and a total of 39 phages when all samples were considered together, could be distinguished by morphological criteria. The total number of phages was estimated to be on the order of 10-8/ml. [TOP OF PAGE]

  29. Isolation and characterization of bacteriophages specific for Rhizobium leguminosarum biovar phaseoli. Dhar, B., Upadhyay, K.K., Singh, R.M. (1993). Canadian Journal of Microbiology 39:775-779. Two lytic phages, designated as H3V and R2V, specific for Rhizobium leguminosarum biovar phaseoli, were isolated and characterized. Phage H3V was active against four indigenous isolates (HURR-3, HURR-21, HURR-35, and HURR-56) and two standard strains (RCR-3605 and USDA-2669) whereas R2V was specific to one indigenous (Raj-2) and one standard (USDA-2676) strain; there was no cross infectivity. Both phages had distinct morphology; phage H3V had an oblate polyhedral head (58 .times. 76 nm) and a flexible noncontractile tail (120 .times. 10 nm), while phage R2V had a hexagonal head (56 nm wide) and a very short tail (11 .times. 10 nm). The lytic cycle of phage R2V requires Ca2+ ions (1 mM), which considerably reduce its latent period and burst size. Adsorption and one-step growth experiments of phages revealed that H3V had a slower adsorption rate (0.56 .times. 10-0 cm3/min), a longer latent period (255 min), and a higher burst size (240 plaque-forming units/cell) than R2V, which had an adsorption rate of 0.94 .times. 10-9 cm3/min, a 210-min latent period, and a burst size of 200 plaque-forming units/cell. Inactivation of these phages by heat, osmotic shock, and uv irradiation showed that phage H3V was comparatively more sensitive than R2V. These phages were frequently detected in healthy nodules of French beans (Phaseolus vulgaris) at two different field locations and no correlation between phage titer and nodule size or colour was observed. Phage titer varied from 2.8 .times. 102 to 1.2 .times. 106 plaque-forming units/nodule. [TOP OF PAGE]

  30. Inactivation of bacteria and coliphages in highly polluted by secondary effluent and pretreated surface water through UV irradiation at a pilot plant scale. Dizer, H., Bartocha, W., Seidel, K., Lopez, P., Grohmann, A. (1993). Zentralblatt fuer Hygiene und Umweltmedizin 194:490-507. The water of a channel in Berlin which is highly polluted by municipal sewage effluent is treated at the phosphate elimination plant (PEP) Tegel by flocculation and filtration in order to reduce eutrophication in the following Lake Teget. The elimination of bacteria and coliphages in the effluent of the PEP was investigated in a scale pilot UV irradiation reactor installed at the outled of the PEP Tegel. The influence of technical parameters such as flow rate and the arrangement of 23 UV lamps in the reactor on the inactivation was tested. The UV irradiation dose was calculated 119 mJ/cm-2 and 49 mj/cm-2 at a flow rate of 50m-3/h and 120 m-3/h, respectively and for an irradiation zone of 97.5 cm. The colony count of bacteria and concentrations of coliform organisms, E. coli, and feacal streptococci as well as the plaque forming units of coliphages in the influent of the UV reactor were reduced 2-3 lg units by an irradiation dose of 119 mJ/cm-2. These elimination was found being only one lg unit at a UV irradiation dose of 49 mJ/cm-2. The concentration of E. faecalis and Coliphages f2 seeded into the influent of the UV reactor decreased after UV irradiation by 119 mj/cm-2 by 2-4 lg units and 1-2 power of magnitude, respectively. A UV dose of 49 mJ/cm-2 caused only a 90% elimination of E. faecalis and a 75 % inactivation of Coliphages f2. Due to heterogenous distribution and the different retention period of the inflowing water in the irradiation zone, the inactivation of E. faecalis and Coliphages f2 was unequal. Both test organisms decreased in the middle of the reactor up to 2 lg units more than at the sides of the reactor. The hygienic-microbiological quality of a secondary effluent from sewage treatment plants can be improved by a combination of flocculation-filtration and UV irradiation due to their additive elimination effect. However, this UV reactor, which was tested under field conditions can only ensure the inactivation of bacteria and coliphages in the pretreated effluent, if more homogenous distribution of the inflowing water can be achieved. Further, the water must be irradiated by a higher UV dose. [TOP OF PAGE]

  31. Superinfection immunity of mycobacteriophage L5: application for genetic transformation of mycobacteria. Donnelly-Wu, M.K., Jacobs, W.R., Hatfull, G.F. (1993). Mol. Microbiol. 7:407-417. [TOP OF PAGE]

  32. Quality control of bacterial enumeration. Donnison, A.M., Ross, C.M., Russell, J.M. (1993). Appl. Environ. Microbiol. 59:922-923. Standard bacterial suspensions can be used to assess test method performance, via control charts, and inhibition of recovery when analyzing water samples. Variability in standard suspensions prepared from different strains and species and the use of frozen environmental samples for quality control for spore and bacteriophage analyses are also discussed. [TOP OF PAGE]

  33. Many-trillionfold amplification of single RNA virus particles fails to overcome the Muller's ratchet effect. Duarte, E.A., Clarke, D.K., Moya, A., Elena, S.F., Domingo, E., Holland, J. (1993). J. Virol. 67:3620-3623. We showed earlier that transfers of large populations of RNA viruses lead to fitness gains that repeated genetic bottleneck transfers result in fitness losses due to Muller's ratchet. In the present study, we examined the effects of genetic bottleneck passages intervening between population passages, a process akin to some natural viral transmissions, using vesicular stomatitis virus as a model. Our findings show that the pronounced fitness increases that occur during two successive population passages cannot overcome the fitness decreases caused by a single intervening genetic bottleneck passage. The implications for natural transmission of RNA viruses are discusses. [TOP OF PAGE]

  34. Characterization of bacteriophages of Erwinia ananas. Eayre, C.G., Robertson, N.L. (1993). Phytopathology 83:1354 [TOP OF PAGE]

  35. Viral extinctions in deep-sea species [letter] [see comments]. Emiliani, C. (1993). Nature 366:217-218. [TOP OF PAGE]

  36. Extinction and viruses. Emiliani, C. (1993). BioScience 31:155-159. [TOP OF PAGE]

  37. A Functional Biology of Parasitism. Ecological and Evolutionary Implications. Esch, G.W., Fernández, J.C. (1993). Chapman and Hall, New York.[TOP OF PAGE]

  38. Characterization of a temperate phage hosted by Alcaligenes eutrophus strain A5. Faelen, M., Merlin, C., Geuskens, M., Mergeay, M., Toussaint, A. (1993). Res. Microbiol. 144:627-631. Nineteen strains of Alcaligenes eutrophus were tested for the presence of prophages. One strain that lysed upon mitomycin C treatment produced a phage which could not form plaques on any of the strains available. DNA extracted from partially purified phage lysates was digested with various restriction enzymes which showed that the 42 kb long viral double-stranded DNA circularizes by means of cohesive ends. To our knowledge, this is the first description of a phage for the genus Alcaligenes. [TOP OF PAGE]

  39. Interactions of temperate bacteriophages of Streptococcus salivarius subsp. thermophilus with lysogenic indicators affect phage DNA restriction patterns and host ranges. Fayard, B., Haefliger, M., ACCOLAS, J.-P. (1993). Journal of Dairy Research 60:385-399. [TOP OF PAGE]

  40. Characterization of Bacillus polymxya isolates from different Brazilian soils. Ferreira, E.C.N., Seldin, L. (1993). Revista de Microbiologia 24:151-155. Seventy-eight Bacillus polymyxa isolates were obtained from different Brazilian soils and characterized for the presence of genetic markers which could be used in recombination experiments within this species. Their DNAs were obtained and it could be observed that 4 isolates showed the presence of plasmids with similar molecular weight. Thirty-two isolates (including those containing the plasmids) were chosen for further studies. All strains showed resistance to polymyxin-B and to bacitracin and sensitivity to the other antibiotics tested. Also, all isolates produced an inhibitory substance against one strain of Staphylococcus aureus and 7 against a Pseudomonas strain. From the 32 isolates, 25 were lysed by EPy-2 phage, specific to B. Polymyxa and 2 were able to fix nitrogen (acetylene reduction test). However, none of these characteristics showed by the different isolates could be correlated to the presence of the plasmids. The strains cured from the plasmid, obtained in this work, showed the same phenotypic characteristics presented by the strains harboring the plasmids. [TOP OF PAGE]

  41. Characterization of a prolate-headed bacteriophage of Lactobacillus delbrueckii ssp. lactis, and its DNA homology with isometric-headed phages. Forsman, P. (1993). Archives of Virology 132:321-330. A new Lactobacillus delbrueckii subsp. lactis bacteriophage, JCL 1032, was characterized. JCL 1032 had a small, elongated prolate head, and a long non-contractile tail with cross-bars. The restriction map of JCL 1032 genome was constructed with five endonucleases. The genome was 45.8 kb in size, and it had cohesive ends (cos). Molecular masses of the phage structural proteins were also determined. JCL 1032 showed DNA homology with morphologically dissimilar, isometric-headed phages of Lb. delbrueckii (subsp. lactis and subsp. bulgaricus) when analyzed by Southern hybridization. Although in general JCL 1032 was only distantly related to isometric-headed phages, there were also a few short highly homologous (minimal homology 84%) DNA regions. [TOP OF PAGE]

  42. Structural similarity and genetic homology between Lactobacillus casei bacteriophages isolated in Japan and in Finland. Forsman, P., Tanskanen, J., Alatossava, T. (1993). Bioscience Biotechnology and Biochemistry 57:2043-2048. Three Lactobacillus casei bacteriophages, LC-NU, PL-1, and vphi-FSW, were compared. Phage LC-Nu, which has not been previously characterized, originated from a local cheese plant in Finland. Phages PL-1 and vphi-FSW (isolated in Japan) represent the most thoroughly studied L. casei phages so far. All three phages had similar morphotypes, but still had different patterns of structural proteins, as analyzed by SDS-PAGE. The phages differed also in types of genome organization: LC-Nu and PL-1 had cohesive ends in their DNAs, and the DNA of vphi-FSW was circularly permuted. The initiation site and orientation of packaging of vphi-FSW DNA were identified. The homologies between the phage genomes were analyzed by Southern hybridization. About one-third of each phage genome was highly homologous with other phages (homology over 85%), and two-thirds were slightly homologous (homology between 65% and 76%). DNAs from five industrial L. casei strains were also tested for homology with phage LC-Nu DNA. Phage LC-Nu related sequences were present in all the L. casei strains tested. [TOP OF PAGE]

  43. Viruses in marine food webs. Fuhrman, J.A., Wilcox, R.M., Noble, R.T., Law, N.C. (1993). pp. 295-298. In In Guerrero, R. and Pedros-Alio, C. (eds.), Trends in microbial ecology. Spanish Society for Microbiology, Barcelona. [TOP OF PAGE]

  44. Viruses in marine planktonic systems. Fuhrman, J.A., Suttle, C.A. (1993). Oceanography 6:50-62. The last 10-15 years have seen major changes in our views of marine planktonic food webs, primarily from the realization that prokaryotic microorganisms and small eukaryotes are responsible for a significant fraction, often 50% or more, of the primary production and heterotrophic consumption of organic matter in these systems. However, it has only been in the past few years that marine scientists have investigated the roles of viruses in ecological processes. Although this research area is only in its infancy, early results suggest that viruses may be important agents in the mortality or marine microorganisms and in controlling their genetic compositions. This paper will summarize the experiments and measurements that have led to this suggestion as well as the conceptual frame-work within which they are interpreted. [TOP OF PAGE]

  45. Grazing by marine nanoflagellates on viruses and virus-sized particles: Ingestion and digestion. González, J.M., Suttle, C.A. (1993). Mar. Ecol. Prog. Ser. 94:1-10. We examined grazing of marine viruses and bacteria by natural assemblages and cultures of phagotrophic nanoflagellates. Ingestion rates were determined using fluorescently-labelled viruses (FLVs) and bacteria (FLB), and 50 or 500 nm-diameter fluorescent microspheres (FMs). Calculated clearance rates of viruses by natural nanoflagellate assemblages were about 4 % of those for bacteria when the bacteria and viruses were present at natural concentrations. Different viruses were ingested at different rates with the smallest virus being ingested at the slowest rate. As well, we found differences in digestion times for the same flagellates grazing on different viruses and for different flagellate assemblages grazing on the same viruses. 50 nm FMs were used as a control for egestion of undigested particles. As rates of digestion were greater than those for ingestion both processes would occur simultaneously; hence, our estimates of grazing rate are likely conservative. Ingestion rates were positively correlated with the concentration of 50 nm FMs. Discrimination against 50 nm FMs in favor of FLVs was also observed. Our calculations suggest that viruses may be of nutritional significance for phagotrophic flagellates. When there are 106 bacteria ml-1 and 107 to 108 viruses ml-1, viruses may represent 0.2-9 % of the carbon, 0.3-14 % of the nitrogen and 0.6-28 % of the phosphorus that the flagellates obtain from ingestion of bacteria. This study demonstrates that both natural assemblages and cultures of phagotrophic nanoflagellates consume and digest a variety of marine viruses, thereby deriving nutritional benefit and serving as a natural sink for marine viral particles. In addition, these results imply that some nanoflagellates are likely capable of consuming a wide spectrum of organic particles in the colloidal size range. [TOP OF PAGE]

  46. Characterization of loosely associated material from the cell surface of Lactococcus lactis ssp. cremoris E8 and its phage-resistant variant strain 398. Gopal, P.K., Crow, V.L. (1993). Appl. Environ. Microbiol. 59:3177-3182. Loosely associated material (LAM) was isolated by gentle extraction procedures from the cell surface of Lactococcus lactis subsp. cremoris E8 and its phage-resistant variant strain 398. LAM from both strains was chemically characterized, and its role in the adsorption of three small isometric bacteriophages, PHI 618, PHI 833, and PHI 852, to the cell surface of the two strains was investigated. The phage-resistant strain (strain 398) produced LAM which differed significantly from the material produced by the parent strain. The total yield of LAM from strain 398 was two- to threefold higher than that from strain E8, and the material contained fivefold more rhamnose and twofold more galactose. Polyacrylamide gel electrophoretic analysis showed that LAM from strain 398 lacked a 21-kDa protein which was present in LAM from the parent strain. Inhibition studies of phage binding by using isolated LAM from two strains showed that although LAM from strain E8 reduced the titer of PHI 618 and PHI 852 by 53 and 82% respectively, LAM from strain 398 had no effect on the plaque-forming ability of any of the three phages tested. Treatment of LAM from strain E8 with sodium metaperiodate destroyed its ability to bind with PHI 618 and PHI 852. Phenotypically, strain 398 differed from its parent strain E8 in that it was more prone to cell lysis and required an osmotically adjusted buffer system for the extraction of LAM. [TOP OF PAGE]

  47. Heat shock-induced axenic growth of Bdellovibrio bacteriovorus. Gordon, R.F., Stein, M.A., Diedrich, D.L. (1993). J. Bacteriol. 175:2157-2161. The bdellovibrios are obligately predatory bacteria that attack other gram-negative bacteria. They grow only in the periplasmic space of prey unless they mutate to forms that can grow axenically. A culture medium that promoted enhanced growth of prey-independent bdellovibrios was developed. The ability of this medium to support the growth of prey-dependent bdellovibrios was tested under transcription-altering conditions. This approach tested the hypothesis that the inability to grow prey-dependent bdellovibrios in artificial media was rooted in both nutritional and transcriptional signal deficiencies. It was assumed that nutritional deficiencies had been resolved and that empirically applied artificial signals may evoke the expression of genes required for axenic growth of bdellovibrios. Prey-dependent bdellovibrios could be grown in PPYE medium (0.1% proteose peptone 3 and 0.03% Bacto yeast extract adjusted to pH 7.0 and supplemented with 3 mM MgCl2 and 2 mM CaCl2 after autoclaving) after heat shock, and subsequent rounds of growth occurred after additional heat shocks. Heat shock may have generated or simulated signals normally derived from prey. [TOP OF PAGE]

  48. Large virus-like particles from vacuoles of phaeodarian radiolarians and from other marine samples. Gowing, M.M. (1993). Mar. Ecol. Prog. Ser. 101:33-43. [TOP OF PAGE]

  49. Comparison of methods for the recovery and quantitation of coliphage and indigenous bacteriophage from marine waters and sediments. Grabow, W.O.K., Reynolds, K.A., Rose, J.B., Giordano, A.T. (1993). pp. 115-117. In In Morris, R.W. and Dufour, A.P. (eds.), HEALTH-RELATED WATER MICROBIOLOGY. PERGAMON PRESS, OXFORD (UK). A variety of anthropogenic influences on marine coastal waters introduces populations of human enteric bacteria and their bacteriophage, some of which may be indicators of municipal waste contamination. This work was undertaken to examine methods for recovery and detection of coliphage in marine waters and sediments. Seeded studies were used to compare viradel and Ultrafiltration methods for the recovery and concentration of both indigenous and introduced viruses from seawater. Ultrafiltration recoveries of MS2 averaged 29.3% in artificial seawater. Viradel methods used to concentrate MD1 coliphage averaged 18.7% recovery when used with natural seawater. A variety of eluants were examined for recovery of phage from sediments. Recoveries ranged from 0.8-100% depending on the type of phage and eluant used. No eluant was capable of providing more efficient recoveries over another, however, indigenous phage 16 was isolated more efficiently than introduced tailed phages T2 and MD1. For phage quantitation, plaque assay counts were compared to particle counts using TEM. TEM counts were usually higher than PFUs in artificial seawater concentrates but lower with eluted marine sediments. Environmental surveys revealed that phage could sometimes be isolated from sediments when they could not be detected in the overlying water column. Preliminary data showed phage could be isolated from sea cucumbers and sponges at higher concentrations than in their surrounding habitats. Therefore, with the development of efficient elution and rapid quantitation techniques, sediments and sea organisms are the most appropriate sampling sites for detection of marine phage populations. [TOP OF PAGE]

  50. Detection of hepatitis A virus in sewage sludge by antigen capture polymerase chain reaction. Graff, J., Ticehurst, J., Flehmig, B. (1993). Appl. Environ. Microbiol. 59:3165-3170. [TOP OF PAGE]

  51. Plant, phage, bacterium: A new hypothesis on their interrelation. Gvozdyak, R.I. (1993). Mikrobiologicheskii Zhurnal (Kiev) 55:92-94. A new hypothesis on plant-phage-bacterium interrelation is under consideration. Conditions for moderate phage elimination from bacterial cells can be created as a result of plant pathogenic bacteria penetration into plant tissue. It was experimentally confirmed that plants can induce phage elimination from bacterial cells and as a result use bacterial prophage for their protection. The second part of the hypothesis, i.e., formadion of phages from plant DNA, needs experimental evidence. [TOP OF PAGE]

  52. Permeability of latex and thermoplastic elastomer gloves to the bacteriophage phi X174. Hamann, C.P., Nelson, J.R. (1993). AMERICAN JOURNAL OF INFECTION CONTROL 21:289-296. BACKGROUND: Most studies challenging the integrity of the glove barrier have compared the permeability of vinyl and latex gloves. However, no studies of a new nonlatex, nonvinyl thermoplastic elastomer have been reported. This pilot study therefore compared the protective barriers provided by latex and thermoplastic elastomer surgical gloves against penetration of the bacteriophage phi X174. METHODS: Twenty thermoplastic elastomer gloves and 25 commercially available latex gloves (20 brand 1, 5 brand 2) were filled with a sterile serum surrogate and exposed to the phi X174 virus in a flask, with shaking for 180 minutes at 37 degrees C. Aliquots of 5 ml were withdrawn at baseline, 30, 60, 120, and 180 minutes and assayed by a standard plaque assay. The remaining contents of the gloves were then tested by an extremely sensitive qualitative assay (plaque assay without dilution of the sample). RESULTS: With the standard plaque assay, virus was detected in 30% of the brand 1 latex gloves, in 80% of the brand 2 latex gloves, but in none of the thermoplastic elastomer gloves. The qualitative assay, which can detect even a single virus in the entire glove contents, had positive results for 30% of the thermoplastic elastomer gloves, 70% of the brand 1 gloves, and 100% of the brand 2 gloves. CONCLUSIONS: Despite the small sample, the results of this stringent assay suggest that the mechanical barrier offered by thermoplastic elastomer gloves is equal to or better than that provided by the latex gloves tested. Clinical studies are needed to evaluate thermoplastic elastomer gloves, which may withstand mechanical stress better than latex or vinyl. Thermoplastic elastomer gloves may therefore be a desirable alternative for health care workers in high-risk settings or for individuals with latex allergies. [TOP OF PAGE]

  53. Inactivation of viruses during ultraviolet light treatment of human intravenous immunoglobulin and albumin. Hart, H., Reid, K., Hart, W. (1993). VOX SANGUINIS 64:82-88. A comparison of ultraviolet (UV) irradiation of two wavelength ranges UVB (280-320 nm) and UVC (lower than 280 nm) showed that UVC in particular could very effectively inactivate, in intravenous immunoglobulin (IVIG) and albumin preparations, non-enveloped and non-acid labile model viruses (i.e., Polio 2 and T4 phage) and dry heat-resistant viruses (vaccinia and T4 phage). This effective virucidal treatment (5 min, 5,000 J/m2 dose) was achieved before an unacceptable level of IVIG aggregates occurred. The use of UV irradiation to inactivate infectious agents could add safety and supplement current methods, e.g. solvent/detergent, low pH, which do not inactivate non-enveloped, non-acid labile or dry-heat-resistant viruses at present. [TOP OF PAGE]

  54. Bacteriophages as models of human enteric viruses in the environment. Havelaar, A.H. (1993). ASM News 57:3121-3126. [TOP OF PAGE]

  55. F-specific RNA bacteriophages are adequate model organisms for enteric viruses in fresh water. Havelaar, A.H., Olphen, M., Drost, Y.C. (1993). Appl. Environ. Microbiol. 59:2956-2962. Culturable enteroviruses were detected by applying concentration techniques and by inoculating the concentrates on the BGM cell line. Samples were obtained from a wide variety of environments, including raw sewage, secondary effluent, coagulated effluent, chlorinated and UV-irradiated effluents, river water, coagulated river water, and lake water. The virus concentrations varied widely between 0.001 and 570/liter. The same cell line also supported growth of reoviruses, which were abundant in winter (up to 95% of the viruses detected) and scarce in summer (less than 15%). The concentrations of three groups of model organisms in relation to virus concentrations were also studied. The concentrations of bacteria (thermotolerant coliforms and fecal streptococci) were significantly correlated with virus concentrations in river water and coagulated secondary effluent, but were relatively low in disinfected effluents and relatively high in surface water open to nonhuman fecal pollution. The concentrations of F-specific RNA bacteriophages (FRNA phages) were highly correlated with virus concentrations in all environments studied except raw and biologically treated sewage. Numerical relationships were consistent over the whole range of environments; the regression equations for FRNA phages on viruses in river water and lake water were statistically equivalent. These relationships support the possibility that enteric virus concentrations can be predicted from FRNA phage data. [TOP OF PAGE]

  56. Outbreak of foodborne and waterborne viral gastroenteritis. Hedberg, C.W., Osterholm, M.T. (1993). Clinical Microbiology Reviews 6:199-210. [TOP OF PAGE]

  57. Characterisation of a Helicobacter pylori phage (HP1). Heintschel, v.H., Nalik, H.P., Schmid, E.N. (1993). J. Med. Microbiol. 38:245-249. The infection of two Helicobacter pylori strains with a phage-containing supernate of the lysogenic H. pylori strain IMMi 290/89 resulted in a lytic cycle and propagation of phage HP1. In negatively-stained preparations, the empty phage heads measured 55-60 nm in diameter and mature heads measured 50 nm. The flexible, striated phage tail was c. 170 nm in length and 9.5 nm in diameter. The phage showed a mean density of 1.40 g/cm3 in sucrose-density gradients and contained double-stranded DNA c. 22,000 bp in length. [TOP OF PAGE]

  58. Use of MS2 coliphage as a surrogate for enteric viruses in surface waters disinfected with ozone. Helmer, R.D., Finch, G.R. (1993). Ozone Science & Engineering 15:279-293. The purpose of this study was to determine the relative inactivation of MS2 coliphage (American Type Culture Collection strain 15597-B1) and heterotrophic plate count bacteria using raw surface water under a variety of naturally occurring conditions. It was found that the applied ozone dose and dissolved organic carbon had the most impact on ozone disinfection of MS2 coliphage and HPC bacteria. The dissolved organic carbon was found to compete for the ozone and significantly reduce the inactivation of both the coliphage and the bacteria. Furthermore, it was observed that the presence of any ozone residual inactivated greater than 4 logs MS2 coliphage and 2 logs heterotrophic plate count bacteria within a 30 second contract time. Ozone residuals greater than 0.20 mg/L inactivated greater than 5 logs MS2 coliphage and 3 logs heterotrophic plate count bacteria also within 30 second contact time. Comparison of inactivation studies indicate that MS2 coliphage is probably more sensitive to ozone than enteric viruses. It was concluded that the regulatory agencies should reevaluate their recommendations for using MS2 coliphage as an ozone disinfection indicator of enteric viruses. [TOP OF PAGE]

  59. Bacteriophage and bacteriophage resistance in lactic acid bacteria. Hill, C. (1993). FEMS Microbiol. Rev. 12:87-108. The study of bacteriophage-host interactions has been instrumental in the development of genetic systems in many genera, and laid many of the foundations of modern molecular genetics. Research into bacteriophage and bacteriophage resistance in the lactic acid bacteria has moved into a new and exciting dimension in recent years. Mechanisms such as adsorption inhibition, restriction and modification, and abortive infection which have been detected and described phenotypically over the past decade are now being subjected to molecular analysis, and this has led to a better understanding of the nature and variety of resistance systems employed by lactic acid bacteria to combat phage attack. In addition, analysis of different bacteriophage has increased our knowledge of these ubiquitous particles to the point where it is possible to construct novel phage resistances based on the phage genome itself. This review outlines the recent progress in the molecular analysis of bacteriophage, bacteriophage resistance and counter resistance, and the construction of novel resistance mechansims. [TOP OF PAGE]

  60. Production of bacteriolytic enzyme by bacteriophage from seawater. Hirayama, S., Ueda, R., Sugata, K., Kamiyoshi, H. (1993). TEMP 99/06/16 57:2166-2167. A system (pair) of bacteriophage pA1 and the host bacterium Vibrio sp. A1 was isolated from seawater. The lysate of host cells infected with the phage showed a significant becteriolytic activity with wider lytic action spectra, more susceptibility at alkaline pH (=9) and higher stability of lytic activity in the lysate compared with other phage-induced lysins reported so far. [TOP OF PAGE]

  61. PilS and PilR, a two-component transcriptional regulatory system controlling expression of type 4 fimbriae in Pseudomonas aeruginosa. Hobbs, M., Collie, E.S.R., Free, P.D., Livingston, S.P., Mattick, J.S. (1993). Molecular Microbiology 7:669-682. Transposon mutagenesis was used to identify genes necessary for the expression of Pseudomonas aeruginosa type 4 fimbriae. In a library of 12,700 mutants, 147 were observed to have lost the spreading colony morphology associated with the presence of functional fimbriae. Of these, 28 had also acquired resistance to the fimbrial-specific bacteriophage PO4. The mutations conferring this phage resistance were found to have occurred at at least six different loci, including the three that had been previously shown to be required for fimbrial biosynthesis or function: the structural subunit (piA) and adjacent genes (piB,C,D), the twitching motility gene (piT), and the sigma 54 RNA polymerase initiation factor gene (rpoN). One novel group of phage-resistant mutants was identified in which the transposon had inserted near sequences that cross-hybridized to an oligonucleotide probe designed against conserved domains in regulators of RpoN-dependent promoters. These mutants had no detectable transcription of piA and did not produce fimbriae. A probe derived from inverse polymerase chain reaction was used to isolate the corresponding wild-type sequences from a P. aeruginosa PAO cosmid reference library, and two adjacent genes affected by transposon insertions, piS and piR, were located and sequenced. These genes were shown to be capable of complementing the corresponding mutants, both at the level of restoring the phenotypes associated with functional fimbriae and by the restoration of piA transcription. The piSR operon was physically mapped to SpeI fragment 5 (corresponding to about 72-75/0 min on the genetic map), and shown to be located approximately 25 kb from piA-D. PiS and PiR clearly belong to the family of two-component transcriptional regulatory systems which have been described in many bacterial species. PiS is predicted to be a sensor protein which when stimulated by the appropriate environmental signals activates PiR through kinase activity. PiR then activates transcription of piA, probably by interacting with RNA polymerase containing RpoN. The identification of piS and piR makes possible a more thorough examination of the signal transduction systems controlling expression of virulence factors in P. aeruginosa. [TOP OF PAGE]

  62. Bacteriophage as models for virus removal from Pacific oysters (Crassostrea gigas) during re-laying. Humphrey, T.J., Martin, K. (1993). Epidemiology and Infection [EPIDEMIOL. INFECT. ] 111:325-335. A study was undertaken to examine the feasibility of using naturally-occurring bacteriophages to assess the impact of re-laying on levels of viral contamination in Crassostrea gigas, the Pacific oyster. Two phages were chosen. One, male-specific (F+), was enumerated using Salmonella typhimurium. The other, a somatic phage, was detected using an, as yet, uncharacterized Escherichia coli. Investigations, using a variety of re-laying sites, demonstrated that numbers of F + phage in oyster tissue declined more rapidly than those of somatic phage. For example, in oysters placed in commercially-used sea water ponds, F+ phage reached undetectable levels within 2-3 weeks, whereas somatic phage could still be detected 5 weeks after re-laying. The studies suggest that F+ phage may not be a suitable indicator for virus removal and that somatic phage may be better suited to this role. [TOP OF PAGE]

  63. The seasonal distribution of some bacteriophages in the akron sewage treatment plant. Huynh, T.D., Kory, M.M. (1993). Ohio Journal of Science 93:48-50. Bacteriophages are present in all human and animal sewage. However, environmental factors, such as the change in seasons, may affect the composition and viability of phages in sewage. The consequence of seasonal change (fall, winter, summer) on the isolation from raw sewage of bacteriophages specific for Escherichia coli, Pseudomonas aeruginosa, and Enterococcus faecalis were studied. The total number of phages isolated in each season varied little. However, the bacteriophage populations did vary concurrently with the change of seasons, with some phages isolated only in one season of the year (i.e., seasonal phage strains). There were many seasonal strains of E. coli phages (17 of the 43 isolated) and Enterococcus phages in the sewage (12 of the 15 isolated), but only a few seasonal Pseudomonas phages (3 of the 15 isolated). While the time of year that the seasonal phages were isolated varied, no season had the majority of the phage isolates. The present study indicates a seasonal distribution in the isolation of bacteriophages from sewage in Northeastern Ohio USA. [TOP OF PAGE]

  64. A liquid, colorimetric presence-absence coliphage detection method. Ijzerman, M.M., Falkinhami, J.O.I., Hagedorn, C. (1993). Journal of Virological Methods 45:229-234. A liquid, colorimetric presence-absence coliphage detection method based on the induction of beta-galactosidase by Escherichia coli is described. The release of beta-galactosidase in the medium due to lytic cell infections by coliphages permits the hydrolysis of a yellow chromogenic substrate that develops into a distinct red coliphage positive sample, while a coliphage negative sample remains yellow. This method has proven to be rapid, simpler to perform than an agar medium assay, easy to read and interpret, inexpensive, and highly sensitive. [TOP OF PAGE]

  65. Rapid assessment of drug susceptibilities of Mycobacterium tuberculosis by means of luciferase reporter phages [see comments]. Jacobs, W.J., Barletta, R.G., Udani, R., Chan, J., Kalkut, G., Sosne, G., Kieser, T., Sarkis, G.J., Hatfull, G.F., Bloom, B.R. (1993). Science 260:819-822. Effective chemotherapy of tuberculosis requires rapid assessment of drug sensitivity because of the emergence of multidrug-resistant Mycobacterium tuberculosis. Drug susceptibility was assessed by a simple method based on the efficient production of photons by viable mycobacteria infected with specific reporter phages expressing the firefly luciferase gene. Light production was dependent on phage infection, expression of the luciferase gene, and the level of cellular adenosine triphosphate. Signals could be detected within minutes after infection of virulent M. tuberculosis with reporter phages. Culture of conventional strains with antituberculosis drugs, including isoniazid or rifampicin, resulted in extinction of light production. In contrast, light signals after luciferase reporter phage infection of drug-resistant strains continued to be produced. Luciferase reporter phages may help to reduce the time required for establishing antibiotic sensitivity of M. tuberculosis strains from weeks to days and to accelerate screening for new antituberculosis drugs. [TOP OF PAGE]

  66. A study of five bacteriophages of the Myoviridae family which replicate on different gram-positive bacteria. Jarvis, A.W., Collins, L.J., Ackermann, H.W. (1993). Archives of Virology 133:75-84. A comparative study is reported on five phages of the Myoviridae family which propagate on Bacillus subtilis, B. thuringiensis, Enterococcus sp., Lactobacillus plantarum, or Staphylococcus aureus. The phages are morphologically identical and characterized by isometric heads with conspicuous capsomers and by contractile tails with complex base plates. The phages show similar protein profiles, but vary considerably in burst size. Phage DNAs are about 95-166 kb in size and are unrelated by DNA-DNA hybridization and restriction endonuclease analysis. Therefore the phages are unrelated at species level. Implications of these data for our understanding of the development of phage species are discussed. [TOP OF PAGE]

  67. Analysis of phage resistance mechanisms encoded by lactococcal plasmid pAJ2074. Jarvis, A.W. (1993). Canadian Journal of Microbiology 39:252-258. Lactococcal plasmid pAJ2074 is a 74-kb plasmid that confers phage resistance at 30 degree C against all lactococcal phages with prolate heads (referred to as prolate phage), and most small lactococcal phages with isometric heads (referred to as small isometric phage) that have been tested. The presence of pAJ2074 had no effect on phage adsorption or injection of phage DNA. Replication of prolate phage c2 DNA could not be detected in bacterial cells containing the plasmid up to 60 min after phage infection, whereas phage c2 DNA replication could be demonstrated at 20 min in the control strain. With pAJ2074 present there was no detectable growth of phage c2 and an 87% reduction in burst size for the small isometric phage sk1. Infective centers were returned in the presence of pAJ2074 by 99% for phage c2 and by 93% for phage sk1. Plasmid pAJ2074 differed from pTR2030, in that the major effect of pAJ2074 was on prolate phage c2, rather than on the small isometric phage sk1, and no restriction and modification system could be detected. In addition, no DNA homology was detected between pAJ2074 and PTRK67 (derived from pTR2030). A recombinant plasmid pAJ88 containing an 8.4-kb insert from pAJ2074 conferred an intermediate level of phage resistance. The DNA region that encoded reduced phage sensitivity was further defined by the subcloning of a 5.6-kb EcoRV fragment that conferred resistance similar to pAJ88. The possibility of two phage-resistance mechanisms being encoded by pAJ2074 is discussed. [TOP OF PAGE]

  68. The Sym plasmid pRP2JI and at least two other loci of Rhizobium leguminosarum biovar phaseoli can confer resistance to infection by the virulent bacteriophage RL38. Jun, G., Aird, E.L.H., Kannenberg, E., Downie, J.A., Johnston, A.W.B. (1993). FEMS Microbiol. Let. 111:321-326. The virulent Rhizobizium bacteriophage RL38 did not form plaques on R. leguminosarum bv. phaseoli, but did so at high efficiency on a derivative of that strain lacking its symbiotic plasmid pRP2JI. Other strains with large deletions in pRP2JI which removed many nod and nif genes retained resistance to RL38, showing that the gene which confers phage resistance lies elsewhere on the plasmid. Although the wild-type strain of R. leguminosarum bv. phaseoli failed to plate RL38, it was possible to transduce chromosomal markers into this strain, indicating that the 'block' was not at an early stage in the infection process. Two different recombinant plasmids obtained from a clone bank of genomic DNA of R. leguminosarum bv. phaseoli, which appeared to have no DNA in common, both conferred resistance to RL38. Surprisingly, the DNA cloned in each of these plasmids did not originate from pRP2JI. Therefore, several different loci both on the Sym plasmid and elsewhere on the bacterial genome can be involved in conferring resistance to this bacteriophage. [TOP OF PAGE]

  69. Virus-like particles in a monogenean (Platyhelminthes) parasitic in a marine fish. Justine, J.L., Bonami, J.R. (1993). International Journal for Parasitology 23:69-75. In Microcotyle sp., a gill parasite in the marine fish Abudefduf analogus near Dakar, Senegal, various organs were studied by transmission electron microscopy. One of the six worms studied contained virus-like particles located only in the outer layer and in the cytons (deep cell bodies) of the tegument. The tegument ultrastructure is described for both healthy and infected monogeneans. The outer layer of the tegument, 2-5 microns thick, does not have microvilli. The virus-like particles are cytoplasmic, about 70 nm in diameter with a single-layered capsid-like structure 10-12 nm thick, and have an icosahedral symmetry. They originate from viroplasms and accumulate in paracrystalline arrays up to 1 micron in size. By their ultrastructural characteristics, these virus-like particles are related to the Reoviridae or, more probably, the Birnaviridae. This is the third report of viruses in monogeneans, and the first in a polyopisthocotylean monogenean. It is hypothesized that monogeneans could act as vectors of viral diseases among their host fishes. [TOP OF PAGE]

  70. Chlorella viruses in diverse freshwaters in Northeast England. Kang, J.Y., Goulder, R., Wollston, C.J. (1993). Letts. Appl. Microbiol. 16:214-216. [TOP OF PAGE]

  71. Efficacy of thermoplastic elastomer and latex condoms as viral barriers. Kettering, J. (1993). Contraception 47:559-567. The barrier efficacy of a thermoplastic elastomer (TPE) and three brands of latex condoms was compared in a passive-leak test and in a dynamic model of simulated intercourse. Fifteen replicates of each of the condoms were challenged with bacteriophage T7 (100 nm) and the polio virus Type 1 (PV-1, 27 nm). In the passive test, no condom leaked either virus. In the dynamic model, no TPE condoms leaked either virus and no latex condoms leaked T7. Two samples of one commercially available latex condom leaked T7 but not PV-1. These data support that intact latex condoms are effective in vivo viral barriers and extend the finding to TPE condoms as well. Given its substantial equivalence to latex as a viral barrier, TPE condoms are an alternative choice for individuals with latex allergies. The TPE material is also more resistant to common environmental conditions that affect latex adversely and should therefore be a superior choice if condoms must be stored for extended periods in suboptimal conditions. [TOP OF PAGE]

  72. Multiple double-stranded RNA segments are associated with virus particles infecting Trichomonas vaginalis. Khoshnan, A., Alderete, J.F. (1993). J. Virol. 67:6950-6955. Previous studies demonstrated that some isolates of the sexually transmitted protozoan Trichomonas vaginalis are infected with a nonsegmented, double-stranded RNA (dsRNA) virus. A reexamination of the total dsRNA extracted from several virus-harboring isolates indicated the presence of at least three dsRNAs with sizes ranging from 4.8 to 4.3 kbp. The double-stranded nature of each of the three segments was determined by hybridization experiments using riboprobes of opposite polarities obtained from cDNA generated to each of the segments. All three segments were present in agar clones originating from single organisms of T. vaginalis isolates, suggesting that the three segments were not the result of a mixed population of trichomonads harboring different sizes of dsRNA. The three segments were associated with CsCl-purified virus particles, as evidenced by electron microscopy, and RNAse treatment of the preparation containing virus particles did not destroy the dsRNAs. Finally, the individual dsRNA segments were purified for use as probes to determine whether the three dsRNAs shared any sequence homology. Each end-labeled dsRNA segment did not cross-hybridize to any of the other two segments, a finding consistent with the hybridization of labeled cDNAs to only the segments from which they were derived. These results show that the coding capacity of the dsRNA virus may be at least three times greater than that estimated earlier and illustrates further the complexity of this virus-parasite interrelationship. [TOP OF PAGE]

  73. Effect of pH on bacteriophage transport through sandy soils. Kinoshita, T., Bales, R.C., Maguier, K.M., Gerba, C.P. (1993). J. Contaminant Hydrology 14:55-70. [TOP OF PAGE]

  74. Estimation of ruminal bacteriophage numbers by pulsed-field gel electrophroesis and laser densitometry. Klieve, A.V., Swain, R.A. (1993). Appl. Environ. Microbiol. 59:2299-2303. To investigate phage activity in the rumen, a method for quantifying phage has been developed. By differential centrifugation and ultrafiltration, phage particles were separated and concentrated from ruminal fluid. Linear double- stranded DNA from this fraction containing predominately tailed phage was isolated and separated by size, using pulsed-field gel electrophoresis (PFGE). Laser densitometry of gel photographs allowed the numbers of phages with DNA in each size region to be calculated and, therefore, the total numbers per milliliter of ruminal fluid to be estimated. Phage numbers were estimated to be between 3 .times. 109 and 1.6 .times. 1010 particles ml of ruminal fluid-1. The phage population, as gauged by the appearance of DNA on PFGE gels, had two major components. A broad region of DNA between 30 and 200 kb was always present on PFGE gels. It appears this region comprises DNA from a great many different phages and would include most of the temperate phages. In addition, discrete DNA bands ranging in size from 10 to 850 kb were frequently observed. DNA from one such band, of 12 kb in size, was shown to consist primarily of a single DNA type, suggesting that it originated from a specific phage It is postulated that the discrete bands are due to epidemics or blooms of phage activity from specific, probably lytic, phages. The method that has been developed will greatly enhance future investigations into the interactions between the ruminal phage population, the ruminal bacterial population, and animal nutrition and growth. It appears the rumen ecosystem contains a dynamic phage population that is maintained at high numbers by a significant and continual lysis of ruminal bacteria. [TOP OF PAGE]

  75. Structural and molecular biological characterization of a new transducing bacteriophage TT91 of Bacillus thuringiensis. Koroleva, Y., Minenkova, I.B., Shamshina, T.N., Azizbekyan, R.R. (1993). Molekulyarnaya Genetika Mikrobiologiya i Virusologiya 35-38. A new bacteriophage Tt91 of larger size and broad lytical spectrum has been isolated from soil to widen the possibility to study new Bacillus thuringiensis strains. The Tt91 bacteriophage was shown to perform the intravariant transduction and, thus, can be used for genetic mapping. The ultrastructural analysis made it possible to refer bacteriophage Tt91 to morphotype A1 and showed similarity of Tt91 morphological structure to the one of CP-group bacteriophages. The performed comparative analysis of phage-specific proteins has confirmed a possible relation of the bacteriophages and revealed the differences between them. The data on the resistance of Tt91 DNA to majority of site-specific restriction endonucleases (17 out of 18 tested) and on DNA melting in the wide interval of temperatures suggests the presence of possible anomalies in the Tt91 DNA. [TOP OF PAGE]

  76. Phage-mediated selection and the evolution and maintenance of restriction-modification. Korona, R., Levin, B.R. (1993). Evolution 47:556-575. Restriction-modification (R-M) was discovered because it provides bacteria with immunity to phage infection. But, is phage- mediated selection the sole mechanism responsible for the evolution and maintenance of these ubiquitous and multiply evolved systems. In an effort to answer this question, we have performed experiments with laboratory populations of Escherichia coli and phage and computer simulations. We consider two ecological situations whereby phage-mediated selection could favor R-M immunity; i) when bacteria with a novel R-M system invade communities of phage-sensitive bacteria in which there are one or more species of phage, and ii) when bacteria colonize bacterial-free habitats in which phage are present. The results of our experiments indicate that in established communities of bacteria and phage, the advantage R-M provides an invading population of bacteria is ephemeral. Within short order, mutants resistant (refractory) to the phage evolve in the dominant population and subsequently in the invading population. The outcome of competition then depends on the relative fitness of the resistant states of these bacterial clones, rather than R-M. As a consequence of sequential selection for independent mutants, this rapid evolution of resistance occurs even when two and three species of phage are present. While in our experiments resistance also evolved when bacteria colonized new habitats in which phage were present, a novel R-M system greatly augmented the likelihood of their becoming established. We interpret the results of this study as support for the hypothesis that the latter, colonization selection, may play an important role in the evolution and maintenance of restriction-modification. However, we also see these results and other observations we discuss as questioning whether protection against phage is the unique biological role of restriction-modification. [TOP OF PAGE]

  77. Sensitivity of naturally occurring coliphages to type I and type II restriction and modification. Korona, R., Korona, B., Levin, B.R. (1993). Journal of General Microbiology 139:1283-1290. Protection against lethal infections by bacteriophage may seem the most likely role of restriction-modification (R-M) systems in bacteria and the reason for their evolution. There are, however, phenomena which question this phage-mediated selection hypothesis for the maintenance of extant R-M systems. Most prominent among these are the mechanisms phage have to avoid or otherwise limit the effects of the restriction endonucleases produced by their host bacteria. To evaluate the importance of these antirestriction mechanisms in Escherichia coli, we have examined the sensitivity of coliphage from natural and laboratory sources to a series of type I and II R-M systems. The results of our study indicate that, in vivo, restriction endonucleases have no effect on a substantial fraction of naturally occurring coliphage. The absence of restriction sites appears to be the most common reason why these phage are unaffected by type II restriction endonucleases, but other antirestriction mechanisms also operate. On the other hand, the frequency of naturally occurring coliphage sensitive to restriction appears sufficiently great for phage-mediated selection to be a viable hypothesis for the maintenance of R-M in E. coli and its accessory elements. [TOP OF PAGE]

  78. Isolation and properties of a restriction endonuclease BstBSI from the thermophilic soil bacterium Bacillus stearothermophilus BS. Kovalevskaya, N.P., Ivanov, L.Y., Zheleznaya, L.A., Matvienko, N.A. (1993). Molekulyarnaya Genetika Mikrobiologiya i Virusologiya 22-25. A new restriction endonuclease BstBSI was isolated and purified from the thermophilic soil bacterium Bacillus stearothermophilus BS by the blue sepharose and hydroxyapatite chromatographies. The enzyme is an isoschizomer of SnaI from Sphaerotilus natans C. It recognizes the hexanucleotide GTATAC and cleaves DNA in the center of the sequence. The maximal catalytic activity of the endonuclease is registered in 50 mM tris-HCl (pH 9,0) buffer with the high ionic strength (100 mM NaCl) in the presence of 10 mM MgCl-2 at 45 degree C. Glucosylated DNA of the phage T4 is not cleaved by the enzyme. [TOP OF PAGE]

  79. DNA homology in species of bacteriophages active on Pseudomonas aeruginosa. Krylov, V.N., Tolmachova, T.O., Akhverdian, V.Z. (1993). Archives of Virology 131:141-151. [TOP OF PAGE]

  80. Study of biological properties of cholera phages and Vibrio El Tor strains isolated from the environment in Donetsk. Kudryakova, T.A., Evteeva, E.I., Makedonova, L.D., Sayamov, S.R., Dudkina, O.V., Smirnova, E.V. (1993). Gigiena i Sanitariya 14-17. [TOP OF PAGE]

  81. Taxonomic implications of the reactions of representative Bacillus strains to Thermoactinomyces-phage. Kurtboke, D.I., Sivasithamparam, K. (1993). Actinomycetes 4:1-7. [TOP OF PAGE]

  82. Occurrence of Actinomadura phage in organic mulches used for avocado plantations in Western Australia. Kurtboke, D.I., Wilson, C.R., Sivasithamparam, K. (1993). Canadian Journal of Microbiology 39:389-394. Phage infecting Actinomadura verrucosospora, Actinomadura pusilla, and Nocardiopsis flava were isolated from mulches applied to avocado trees at the University of Western Australia experimental plots. The physiochemical properties, plaque morphology, host range, and particle morphology of the phage isolated are described. Taxonomic implications of the reactions of some cell wall chemotype III actinomycetes to Actinomadura phage are also discussed. [TOP OF PAGE]

  83. Use of bacteriophage for the selective isolation of thermophilic actinomycetes from composted eucalyptus bark. Kurtboke, D.I., Murphy, N.E., Sivasithamparam, K. (1993). Canadian Journal of Microbiology 39:46-51. A method was developed to reduce the numbers of thermophilic bacteria on isolation plates, which in turn facilitated the detection and isolation of thermophilic actinomycetes. The method involves exposing the test material to bacteriophage suspensions prior to inoculation on isolation plates. This method was applied to composted eucalyptus bark samples, which were then inoculated on R8 and 1/2 TSA + 0.2% casein hydrolysate agar plates. The phage susceptibility of thermophilic bacteria provided a selective means of reducing their numbers on isolation plates and hence increased the numbers of Thermomonospora, Saccharopolyspora rectivirgula, and thermophilic Streptomyces spp. on these media in comparison with the numbers recorded from control plates. [TOP OF PAGE]

  84. Regulation of proteinase synthesis in Lactococcus lactis. Laan, H., Bolhuis, H., Poolman, B., Abee, T., Konings, W.N. (1993). Acta Biotechnologica 13:95-101. The synthesis of extracellular serine proteinase of Lactococcus lactis was studied during the growth in a batch and a continuous culture on chemically defined media. In a batch culture the proteinase synthesis started during the exponential phase of growth and the highest proteinase concentrations were found at the end of the exponential and beginning of the stationary phase of growth. During the growth in a lactose-limited chemostat with amino acids as the sole source of nitrogen, the specific rate of proteinase synthesis was maximal at a mu of 0.23 h-1. At higher growth rates the proteinase production declined. The proteinase synthesis was dependent on the amino acid sources in the medium. In batch cultures of L. lactis grown on a chemically defined medium with amino acids, the proteinase production was increased four-fold compared to media containing casein or a tryptic digest of casein as the sole source of nitrogen. The inhibition of the rate of proteinase synthesis by casein and peptides was also observed during the growth in a chemostat. The addition of the dipeptide leucylproline (final concentration of 100 mu-M) to a lactose-limited continuous culture during the steady state (D = 0.23 h-1) resulted in a transient inhibition of the rate of proteinase synthesis. This suggested that exogenously supplied peptides control the regulation of proteinase synthesis of L. lactis. [TOP OF PAGE]

  85. Phage enumeration in water from Aragon Imperial channel and river Ebro in Zaragoza. lafarga, M.A., Ezquerra, J., Ferrandez, A., Grasa, B., Alejandre, M.C., Marcen, J.J. (1993). Microbiologia (Madrid) 9:43-52. Zaragoza city supply channel and the river Ebro (up and downstream urban sewage) were studied for the presence of coliphages and B. fragilis phages and their relationship with the bacterian faecal indicators. In the supply channel the coliphages geometric mean was of 130 ufp/100 ml, and showed no correlation with faecal and total coliforms, but it showed indirect correlation with ambiental temperature. In the river Ebro the coliphages geometric mean ranged from 290 to 8,000 ufp/100 ml: the relationship with total and faecal coliforms and faecal streptococci was high, but they were temperature independent. With the methodology utilized B. fragilis phages only were recovered in samples with faecal coliforms levels gt 1 times 10-4 ufc/100 ml. [TOP OF PAGE]

  86. [The isolation of Vibrio alginolyticus bacteriophage]. [Chinese]. Lin, Y., Chen, K., Chen, G., Hu, H. (1993). Wei Sheng Wu Hsueh Pao - Acta Microbiologica Sinica 33:285-289. We identified 4 bacteriophages of V. alginolyticus in 29 ones, which were first isolated from seafood. According to their character of the plaques, they were classified into two kinds: one plaque was clear, the other was opaque. The size of these plaques were different and their diameters are 0.5-3.0mm. By electron microscopy observation, they could be classified into two kinds; one has a long axie and hexagemal head, and a thin-long tail, the other has an equal axie hexagenal head and a very short tail, but the edges and corners aren't clear. The multiplication valence of the phages attained to 10(8-9) pfu/ml. Total lysis rate of 4 bacteriophages was 72.22% to V. alginolyticus. However, the lysis rate of single phage was 9.72-44.4%. 4 bacteriophages all had high host specificity. Cross-lysis reaction wasn't found in the test of original solution of bacteriophages to 612 strains of different genus bacteria and 697 strains of genus Vibrio, but they only showed 39% cross-lysis rate to V. parahaemolyticus and most part of this phenomenon disappeared at 10 RTD of the phages. Thus, the obvious relation of consanguinity was showed between two kinds of bacteria strains. [TOP OF PAGE]

  87. The isolation of Vibrio Alginolyticus bacteriophage. Lin, Y., Chen, K., Chen, G., Hu, H. (1993). Acta Microbiologica Sinica 33:285-289. We identified 4 bacteriophages of V. alginolyticus in 29 ones, which were first isolated from seafood. According to their character of the plaques, they were classified into two kinds: one plaque was clear, the other was opaque. The size of these plaques were different and their diameters are 0.5-3.0 mm. By electron microscopy observation, they could be classified into two kinds; one has a long axie and hexagenal head, and a thin-long tail, the other has an equal axie hexagenal head and a very short tail, but the edges and corners aren't clear. The multiplication valence of the phages attained to 10-8-9 pfu/ml. Total lysis rate of 4 bacteriophages was 72.22% to V. alginolyticus. However, the lysis rate of single phage was 9.72-44.4%. 4 bacteriophages all had high host specificity. Cross-lysis reaction wasn't found in the test of original solution of bacteriophages to 612 strains of different genus bacteria and 697 strains of genus Vibrio, but they only showed 39% crosslysis rate to V. parahaemolyticus and most part of this phenomenon disappeared at 10 RTD of the phages. Thus, the obvious relation of consanguinity was showed between two kinds of bacteria strains. [TOP OF PAGE]

  88. Isolation, classification and molecular characterization of bacteriophages for Enterobacter species. Loessner, M.J., Neugirg, E., Zink, R., Scherer, S. (1993). Journal of General Microbiology 139:2627-2633. Out of 22 Enterobacter phages investigated, nine were found to be suitable for phage typing based on their different lytic spectra on 398 strains of Enterobacter spp. isolated from milk powder and other foods. These phages were compared on the basis of morphology, protein composition, restriction endonuclease patterns and DNA-DNA hybridization. Two phages (WS- EP19, WS-EP13) belonged to the Podoviridae family (morphotype C1), and three (WS-EP20, WS-EP26, WS-EP28) were classified as Siphoviridae (morphotype B1). The other four phages were Myoviridae of the morphological groups A1 ( WS-EP57) and A2 ( WS- EP32, WS-EP94, WS-EP96). SDS-PAGE revealed individual protein profiles for each phage, which corresponded to different restriction enzyme fragment patterns. DNA-DNA hybridization demonstrated the close relationship of phages WS-EP20 and WS-EP26, and of WS-EP94 and WS-EP96. In general, a good correlation was found between groupings obtained with the various methods. The nine phages could be attributed to existing enterobacterial phage species although some differences to the described type phages were observed. [TOP OF PAGE]

  89. Isolation of actinophage that attack some Maduromycete actinomycetes. Long, P.F., Parekh, N.R., Munro, J.C., Williams, S.T. (1993). FEMS Microbiol. Let. 108:195-200. During the course of natural product screening, two actinomycete strains, designated 3828E and 3913E, were isolated from soil collected in the Phillipines and New Zealand, respectively. Strain 3828E released without induction an actinophage. The host isolate was chemotaxonomically identical to members of the revised genus Microtetraspora having both wall chemotype III, sugar pattern B and phospholipid pattern PIV. On the basis of cultural and morphological characteristics, the isolate was most similar to Microtetraspora salmonea. Strain 3913E shared the same chemotaxonomic characteristics as strain 3828E; however, morphological examination revealed the presence of spores arranged distinctively as pairs along aerial hyphae. On this basis, strain 3913E was classified as a member of the genus Microbispora. When re-infected into the soil it had been isolated from, actinophage were recovered that specifically attacked strain 3931E. The presence of phage from both maduromycetes was confirmed by transmission electron microscopy. Neither phage was able to attack a range of other actinomycetes. We believe this to be the first reported isolation of actinophage that attack species of the genera Microtetraspora and Microbispora. [TOP OF PAGE]

  90. Identification and sequence analysis of the replication region of the phage resistance plasmid pCI528 from Lactococcus lactis ssp. cremoris UC503. Lucey, M., Daly, C., Fitzgerald, G. (1993). FEMS Microbiol. Let. 110:249-256. The replication region of the phage resistance plasmid pCI528 from Lactococcus lactis subsp. cremoris UC503 was localized to within a 10-kb HindIII restriction fragment. A 6.3-kb BglII-HindIII subclone of this fragment, cloned into a replication probe vector, allowed replication in Lactococcus but not in Bacillus or Lactobacillus. Sequence analysis revealed an ORF of 1152 bp preceded by a putative ori region containing a 22-bp sequence tandemly repeated three and three-quarter times, a second smaller direct repeat and two inverted repeats. Extensive homology was observed with the well characterized replication region of the small cryptic plasmid pCI305 (Hayes, F., Vos, P., Fitzgerald., G.F., deVos, W. and Daly, C. Plasmid 25, 16-26). [TOP OF PAGE]

  91. Effect of biocides on Pseudomonas aeruginosa phage F116. Maillard, J.-Y., Beggs, T.S., Day, M.J., Hudson, R.A., Russell, A.D. (1993). Letters in Applied Microbiology 17:167-170. [TOP OF PAGE]

  92. Survival of the temperate actinophage PHI-C31 and Streptomyces lividans in soil and the effects of competition and selection on lysogens. Marsh, P., Toth, I.K., Meijer, M., Schilhabel, M.B., Wellington, E.M.H. (1993). FEMS Microbiol. Ecol. 13:13-21. Lysogenic infections were demonstrated in microcosms of sterile soil inoculated with Streptomyces lividans and the vphi-C31 derivative, KC301, in free state or via lysogenized hosts. Intermittent soil mixing caused liberation of KC301 due to lysis of germinating lysogenized and uninfected spores. The presence of lysogenized hosts ensured that KC301 was maintained at a constant density. The lysogen S. lividans TK24 (KC301) achieved a population density lower than that of its non-lysogenized counterpart. Thiostrepton in the soil did not select for the thiostrepton resistance gene of KC301. The long-term survival in soil of a temperate actinophage was demonstrated. [TOP OF PAGE]

  93. Abundance of virus-sized non-DNase-digestible DNA (coated DNA) in eutrophic seawater. Mauryama, A., Oda, M., Higashihara, T. (1993). Appl. Environ. Microbiol. 59:712-717. [TOP OF PAGE]

  94. A field example of bacteriophage as tracers of fractured flow. McKay, L.D., Cherry, J.A., Bales, R.C., Yahya, M.T., Gerba, C.P. (1993). Environ. Sci. Technol. 27:1075-1079. [TOP OF PAGE]

  95. A novel ompC mutation of Escherichia coli K-12 that reduces OmpC and OmpF levels in the outer membrane. Misra, R. (1993). Molecular Microbiology 10:1029-1035. A novel ompC mutation was isolated that not only lowered the amount of its own product, OmpC27, but also reduced the level of OmpF present in the outer membrane. ompC27 codes for a mutant OmpC protein that contains two non-native cysteine residues. The ompC27 allele confers phage resistance by lowering the level of OmpC present in the outer membrane. This effect on OmpC27 was manifested at the level of assembly as a result of disulphide bond formation between the two cysteine residues. This disulphide bonding in OmpC27 also produced a novel phenotype by specifically influencing OmpF levels. The effect of OmpC27 on OmpF was partly a result of a lowering of ompF transcription, and partly a result of an effect at the post-transcription level. The transcriptional effect is likely to be brought about by a defective membrane as a result of the insertion of the disulphide bond containing OmpC27. The post-transcriptional effect of OmpC27 on OmpF could be due to interference at the assembly level. In a dsbA::kan1 background where the in vivo disulphide bonding ability was dramatically reduced, the OmpC27-mediated effects were also curtailed. [TOP OF PAGE]

  96. Production of monoclonal antibodies against the major capsid protein of the Lactococcus bacteriophage u136 and development of an enzyme-linked immunosorbent assay for direct phage detection in whey and milk. Moineau, S., Bernier, D., Jobin, M., Hebert, J., Klaenhammer, T.R., Pandian, S. (1993). Appl. Environ. Microbiol. 59:2034-2040. The only major structural protein (35 kDa) of the lactococcal small isometric-headed bacteriophage u136, a member of the P335 species, was isolated from a preparative sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis. Monoclonal antibodies (MAbs) were raised against the denatured 35-kDa protein. Six MAbs were selected and characterized. Western blots (immunoblots) showed that all MAbs recognized the 35 kDa but also a 45 kDa that is in lower concentration in the phage structure. Binding inhibition assays identified five families of MAbs that recognized nonoverlapping epitopes of the 35- and 45-kDa proteins. Immunoelectron microscopy showed that these two proteins are loclaized within the phage head, therefore indicating that the 45 kDa is a major capsid protein of ul36 and that the 35 kDa is a minor capsid protein. With two MAbs, a sandwich enzyme-linked immunosorbent assay (ELISA) was developed for direct detection of lactococcal phages in whey and milk samples. Whey and milk components, however, interfered with the conduct of the assay. Partial denaturation of milk samples by heat treatment in the presence of SDS and beta-mercaptoethanol removed the masking effect and increased the sensitivity of the assay by 100-fold. With the method used here, 10-7 PFU/ml were detected by the ELISA within 2 h without any steps to enrich or isolate bacteriophages. [TOP OF PAGE]

  97. Differentiation of two abortive mechanisms by using monoclonal antibodies directed toward lactococcal bacteriophage capsid proteins. Moineau, S., Durmaz, E., Pandian, S., Klaenhammer, T.R. (1993). Appl. Environ. Microbiol. 59:208-212. Monoclonal antibodies were used to monitor the accumulation of the major capsid protein of the lactococcal small isometric bacteriophage u136 (P335 species) over the course of a one-step growth curve. A sandwich enzyme-linked immunosorbent assay was then used to distinguish two abortive phage resistance mechanisms, Hsp and Prf. Capsid protein production of u136 was almost totally inhibited by the Hsp-induced abortive mechanism, supportive previous data that this mechanism blocks phage DNA replication. Prf-induced abortive infection only partially (50%) inhibited capsid protein production, suggesting that this mechanism targets some other point, perhaps within transcription or translation processes. The results confirmed that Hsp and Prf act as different targets in the phage lytic cycle. Use of monoclonal antibodies also demonstrated that production of the major capsid protein is a nonlimiting step in the lytic cycle of lactococcal phage u136. [TOP OF PAGE]

  98. A study on phage resistance and plasmid profiles of the mutants of industrial Lactococcus strains deficient in utilization of sugars. Molotova, N.O., Ganina, V.I., Molotov, S.V., Sukhodolets, V.V. (1993). Biotekhnologiya 9-11. The mutants defective in the utilization of lactose, sucrose and fructose were isolated from the group of industrial strains of Lactococcus lactis subsp. lactis and subsp. cremoris. The analysis of plasmid profiles showed the absence in some mutants of plasmid with molecular weight from 45 to 54 kb. Two strains were found, L. lactis subsp. lactis 90 and L. lactis subsp. cremoris ROM in which mutants deficient in lactose utilization had changes in phage resistance spectrum, the changes being in both cases the appearance of sensitivity to different phages. [TOP OF PAGE]

  99. Biological control of mushroom bacterial blotch with bacteriophages. Munsch, P., Olivier, J.M., Fritig, B., Legrand, M.E. (1993). Developments in Plant Pathology 469 [TOP OF PAGE]

  100. Viral dynamics II: A model of the interaction of ultraviolet light and mixing processes on virus survival in seawater. Murray, A.G., Jackson, G.A. (1993). Mar. Ecol. Prog. Ser. 102:105-114. Viruses are an important component in the functioning of marine ecosystems. They are especially vulnerable at the stage when they are free particles seeking a new host. A major factor in viral mortality during this phase is the presence of ultraviolet (UV) radiation. UV radiation penetrates only a short distance into the water column because of a very high attenuation coefficient. Processes that move viruses to the surface change their UV exposure. We have modelled the mortality of viruses subject to UV radiation by means of a Lagrangian Monte-Carlo type model that incorporates viral movements within the mixed layer. For viruses with a given UV-induced surface mortality, mixed-layer depth and UV attenuation coefficient are important factors in their water column mortality. Other more subtle factors can also affect viral mortality: nature of the diurnal thermocline; type of mixing; and the time of day that they are released into the water. Viruses not subject to mixing have their mortality rate enhanced by internal wave motion, although the absolute mortality rates may remain low. Increased UV irradiance associated with atmospheric ozone depletion could significantly change viral mortality in polar environments. UV-induced mortality can be comparable to that from biological factors such as virucidal bacteria. [TOP OF PAGE]

  101. Isolation and partial characterization of three rumen Lactobacillus plantarum bacteriophages. Nemcova, R., Styriak, I., Stachova, M., Kmet, V. (1993). Microbiologica (Pavia) 16:177-180. The first isolation of Lactobacillus plantarum bacteriophages from ruminal fluid is reported. Three bacteriophages were characterized on the basis of plaque morphology, host ranges, stability, electron microscopic morphology and DNA restriction endonuclease digestion patterns. They formed clear plaques and are placed in group A of Bradley's scheme and have identical host ranges. Bacteriophages were stable to urea and chloroform. They were relatively thermostable but partially inactivated by rumen fluid and by acetate. DNA restriction analysis showed that phage L20 had different numbers of cleavage sites in comparison with the next two phages. [TOP OF PAGE]

  102. Bacteriophages induced by ciprofloxacin in a Borrelia burgdorferi skin isolate. Neubert, U., Schaller, M., Januschke, E., Stolz, W., Schmieger, H. (1993). Zentralblatt Fuer Bakteriologie 279:307-315. Two types of tailed bacteriophages were detected by electron microscopy in a Borrelia burgdorferi strain which had been isolated from infected human skin and exposed to the gyrase inhibitor ciprofloxacin. One of these phages displayed an isometric 30 nm head, a neck and a contractile tail 50-64 nm in length with a baseplate, according to an A-1 morphology. The other phage showing a B-1 morphology had a 30 nm isometric head as well and a long non-contractile straight tail 115-130 nm in length without neck and baseplate. Both types of phages could be found together within one plasmolysed spirochetal cell. We conclude that we are dealing with a lysogenic strain of Borrelia burgdorferi carrying at least two different prophages inducible by ciprofloxacin. [TOP OF PAGE]

  103. Study of the marine cyanophytes from the Cabo Frio (Rio de Janeiro, Brazil): II. Hormogonae. Neves, M.H.C.B. (1993). Revista Brasileira de Biologia 52:641-659. A study of the Bentic Marine Cyanophytes-Hormogonae from Cabo Frio Region (Brazil) (RJ) was made within its natural environment, according to the taxonomic hierarchy and taking into account the ecological data. The distinction among species is made in relation to the degree of cell differentiation and the kind of thallus branch. The main species of Hormogonae present in the area studied belong to the Order Oscillatoriales (21), Nostocales (6), Stigonematales (2). Oscillatorales are dominant due to its abundance and richness of species in the littoral studied. [TOP OF PAGE]

  104. Fate of coliforms and coliphages in the sequencing batch reactor (SBR). Ng, W.J., Sim, T.S., Ong, S.L., Ng, K.Y., Ramasamy, M., Tan, K.N. (1993). Bioresource Technology 46:197-205. Performance of the SBR in terms of commonly used physical, chemical and biological parameters has confirmed it to be a viable wastewater treatment option. This study further investigates the use of total coliforms, fecal coliforms and coliphages to evaluate the removal of selected microbiological indicators of potential pathogens by the SBR. Results from a pilot-scale SBR which received clarified sewage from a local treatment works treating a combined (domestic and industrial) sewage showed that increases in REACT time led to increases in the overall removal of the selected microorganisms. On average, up to 96% of total coliform and fecal coliform removals and up to 90% of coliphage removal was possible with the SBR operated with 2.5 h of REACT. During FILL, a long FILL (3 h) resulted in reduction of coliforms while there was generally only a small reduction of coliphages. During REACT, a short REACT resulted in increase in selected microorganisms and the increase in coliphage numbers was sequential to that of coliforms. The SETTLE period was found to be crucial. An effective SETTLE could be achieved by operating the SBR with a REACT time of 2-2-5 h. [TOP OF PAGE]

  105. Phage sensitivity and host range of Rhizobium strains isolated from root nodules of temperature legumes. Novikova, N.I., Pavlov, E.A., Limeshchenko, E.V. (1993). Plant and Soil 151:45-53. Twenty-five Rhizobium strains were isolated from root nodules of Astragalus spp. (10), Hedysarum alpinum (7), Glycyrrhiza pallidiflora (3) and Ononis arvensis (5). The sensitivity of these strains to bacteriophages of Rhizobium loti, R. meliloti, R. galegae and R. leguminosarum was studied. Phages specific to R. loti strains were shown to induce the phage lysis of several Astragalus, Hedysarum and Ononis rhizobia. Ten R. loti strains tested for nodulation abilities on the plant hosts under investigation were able to develop nitrogen-fixing nodules on the Ononis arvensis roots. On the other hand, rhizobia from Ononis and Glycyrrhiza could form an effective symbiosis with Lotus corniculatus plants, so these bacteria are considered to belong to the Rhizobium loti taxon. Bacterial strains isolated from Astragalus and Hedysarum were observed to cross-nodulate their plant hosts as well as Oxytropis campestris, Glycyrrhiza uralensis and Ononis arvensis plants, whereas they could not nodulate Lotus plants. It is concluded that these Rhizobium strains comprise a cross-inoculation group related to Rhizobium loti. [TOP OF PAGE]

  106. Ch2, a novel halophilic archaeon from an Australian solar saltern. Nuttall, S.D., Dyall-Smith, M.L. (1993). International Journal of Systematic Bacteriology [INT. J. SYST. BACTERIOL. ] 43:729-734. A novel halophilic archaeon, strain Ch2, was isolated from a marine solar saltern in Geelong, Australia. The fact that this organism had a dam-methylated genome suggested that it is closely related to the taxon that includes Halobacterium saccharovorum, Halobacterium sodomense, and Holobacterium trapanicum. A sequence analysis of the 16S rRNA gene (Ch2 has three copies of this gene) showed that Ch2 is phylogenetically equidistant from the genera Haloarcula and Haloferax and closely related to H. saccharovorum. The susceptibility of both Ch2 and H. saccharovorum to the recently isolated halophage HF2 supported the hypothesis that these two organisms are closely related. [TOP OF PAGE]

  107. HF1 and HF2: Novel bacteriophages of halophilic archaea. Nuttall, S.D., Dyall-Smith, M.L. (1993). Virology 197:678-684. Two novel halophilic archaebacterial bacteriophages, HF1 and HF2, were isolated from an Australian solar saltern. They were morphologically identical with icosahedral-shaped heads (diameter 58 nm) and contractile tails (length 94 nm). Other similarities included sensitivity to reduced ionic conditions, similar protein profiles by SDS-PAGE, and dsDNA genomes of identical size (73.5 kbp) with analogous restriction patterns. DNA-DNA hybridization data showed the two phages to be closely related. HF1 has a broad host-range, infecting members of three halobacterial genera including Halobacterium salinarium and the genetically well-characterized strain Haloferax volcanii WFD11. Mutants showing increased plating efficiency on alternative hosts were readily selectable. By contrast, HF2 showed a limited host range, confined to the closely related dam-methylated strains Ch2 and H. saccharovorum. [TOP OF PAGE]

  108. Effect of increasing the copy number of bacteriophage origins of replication, in trans, on incoming-phage proliferation. O'Sullivan, D.J., Hill, C., Klaenhammer, T.R. (1993). Appl. Environ. Microbiol. 59:2449-2456. Bacteriophage resistance mechanisms which are derived from a bacteriophage genome are termed Per (phage-encoded resistance). When present in trans in Lactococcus lactis NCK203, Per50, the cloned origin of replication from phage vphi-50, interferes with vphi-50 replication. The per50 fragment was found to afford negligible protection to NCK203 against vphi-50 infection when present in a low-copy-number plasmid, pTRK325. A high-copy-number Per50 construct (pTRK323) dramatically affected vphi-50 infection, reducing the efficiency of plaquing (EOP) to 2.5 times 10-4 and the plaque size to pinhead proportions. This clone also afforded significant protection against other related small isometric phages. Per31 was cloned from phage vphi-31 and demonstrated to function as an origin of replication by enabling replication of per31-containing plasmids, in NCK203, on vphi-31 infection. A low-copy-number Per31 plasmid (pTRK360) reduced the EOP of vphi-31 on NCK203 to 0.3 and the plaque diameter from 1.5 to 0.5 mm. When this plasmid was cloned in high copy number, the EOP was further reduced to 7.2 times 10-7 but the plaques were large and contained Per31-resistant phages. Characterization of these "new" phages revealed at least two different types that were similar to vphi-31, except that DNA alterations were noted in the region containing the origin. This novel and powerful abortive phage resistance mechanism should prove useful when directed at specific, problematic phages. [TOP OF PAGE]

  109. Regulation of antibody responses: the role of complement and adhesion molecules. Ochs, H.D., Nonoyama, S., Zhu, Q., Farrington, M., Wedgewood, R.J. (1993). Clin. Immunol. Immunopathol. 67:S33-S40 [TOP OF PAGE]

  110. Association of bacteriophage particles with toxin production by Clavibacter toxicus, the causal agent of annual ryegrass toxicity. Ophel, K.M., Bird, A.F., Kerr, A. (1993). Phytopathology 83:676-681. The association between Clavibacter toxicus, the causal agent of annual ryegrass toxicity in Australia, and a bacteriophage specific to the bacterium was examined. Wild-type C. toxicus strains (designated type 1) did not produce corynetoxin, the toxin responsible for annual ryegrass (Lolium rigidum) toxicity. When bacteria were infected with the bacteriophage, two types of colonies resulted. One type (type 2) produced toxin and the other (type 3) did not. Antiserum was raised to purified bacteriophage particles. Type 2 bacteria reacted positively to the antiserum in enzyme-linked immunosorbent assay (ELISA) but type 1 and 3 colonies did not. Culture of toxin-producing (type 2) bacteria with antiphase antiserum restored normal colony morphology and eliminated activity in the corynetoxin bioassay. DNA hybridization revealed that bacteriophage DNA was not present in type 1 strains but was present in type 2 and 3 strains. Bacteriophage DNA was not integrated into bacterial DNA and was present in high copy number. Toxin-producing strains had an unusual morphology, and when examined by electron microscopy, the bacterial capsule and cell membrane appeared disrupted. Intact phage particles were visible in transmission electron micrographs of the infected bacteria. Evidence indicated that bacteriophage in toxin-producing bacteria (type 2 colonies) was in a phage-carrier state with C. toxicus, and bacteriophage presence was correlated with production of corynetoxin. [TOP OF PAGE]

  111. Distribution of viral abundance in the reef environment of Key Largo, Florida. Paul, J.H., Rose, J.B., Jiang, S.C., Kellogg, C.A., Dickson, L. (1993). Appl. Environ. Microbiol. 59:718-724. The distribution of viral and microbial abundance in the Key Largo, Fla., reef environment was measured. Viral abundance was measured by transmission electron microscope direct counts and plaque titer on specific bacterial hosts in water and sediment samples from Florida Bay (Blackwater Sound) and along a transect from Key Largo to the outer edge of the reef tract in Key Largo Sanctuary. Water column viral direct counts were highest in Blackwater Sound of Florida Bay (1.2 times 10-7 viruses per ml), decreased to the shelf break (1.7 times 10-6 viruses per ml), and were inversely correlated with salinity (r = -0.97). Viral direct counts in sediment samples ranged from 1.35 times 10-8 to 5.3 times 10-8/cm-3 of sediment and average nearly 2 orders of magnitude greater than counts in the water column. Viral direct counts (both sediment and water column measurements) exceeded plaque titers on marine bacterial hosts (Vibrio natriegens and others) by 7 to 8 orders of magnitude. Water column viral abundance did not correlate with bacterial direct counts or chlorophyll a measurements, and sediment viral parameters did not correlate with water column microbial, viral, or salinity data. Coliphage, which are indicators of fecal pollution, were detected in two water column samples and most sediment samples, yet their concentrations were relatively low (2 to 15/liter for water column samples, and lt 2 to 108/cm-3 of sediment). Our findings indicate that viruses are abundant in the Key Largo environment, particularly on the Florida Bay side of Key Largo, and that processes governing their distribution in the water column (i.e., salinity and freshwater input) are independent of those governing their distribution in the sediment environment. [TOP OF PAGE]

  112. Bacteriophagotherapy and enterosorbtion in treatment of sepsis of newborns caused by gram-negative bacteria. Pavlenishvili, I., Tsertsvadze, T. (1993). Pren. Neon. Infect. 11:104-??? [TOP OF PAGE]

  113. Clostridium perfringens and somatic coliphages as indicators of the efficiency of drinking water treatment for viruses and protozoan cysts. Payment, P., Franco, E. (1993). Appl. Environ. Microbiol. 59:2418-2424. The quality of water in the Ukrainian part of the Danube has been characterized as to mineralization and ecological-sanitary indices. It is shown that the composition and properties of the Danube water flowing into the Ukrainian part are formed mainly in the territory of Bulgaria and Romania; as flowing on along the Bulgarian-Romanian part the quality of water decreases by most indices as a result of anthropogenic pollution. In the present period the prograssing eutrofication and deterioration of water quality in the Ukrainian part of the Danube are observed as compared to the indices of late 70s, that is greatly caused by intensification of phytoplankton vegetation because of water turbidity decrease (especially in low-water years) as a result of the Danube regulated flow. To find the most suitable indicator of viral and parasitic contamination of drinking water, large-volume samples were collected and analyzed for the presence of pathogens (cultivable human enteric viruses, Giardia lamblia cysts, and Cryptosporidium oocysts) and potential indicators (somatic and male-specific coliphages, Clostridium perfringens). The samples were obtained from three water treatment plants by using conventional or better treatments (ozonation, biological filtration). All samples of river water contained the microorganisms sought, and only C. perfringens counts were correlated with human enteric viruses, cysts, or oocysts. For settled and filtered water samples, all indicators were statistically correlated with human enteric viroses but not with cysts or oocysts. By using multiple regression, the somatic coliphage counts were the only explanatory variable for the human enteric virus counts in settled water, while in filtered water samples it was C. perfringens counts. Finished water samples of 1,000 liters each were free of all microorganisms, except for a single sample that contained low levels of cysts and oocysts of undetermined viability. Three of nine finished water samples of 20,000 liters each revealed residual levels of somatic coliphages at 0.03, 0.10, and 0.26 per 100 liters. Measured virus removal was more than 4 to 5 log-10, and cyst removal was more than 4 log-10. Coliphage and C. perfringens counts suggested that the total removal and inactivation was more than 7 log-10 viable microorganisms, C. perfringens counts appear to be the most suitable indicator for the inactivation and removal microorganism of viruses in drinking water treatment. They also appear to have a relationship to cysts and oocysts and could be used as indicators of their inactivation and removal. We propose their use as surrogates for virus and parasite testing of drinking water. [TOP OF PAGE]

  114. Effect of the submicron size fraction including viruses on the formation of algal flocs (marine snow) in the sea. Peduzzi, P., Weinbauer, M.G. (1993). Limnol. Oceanogr. 38:1562-1565. [TOP OF PAGE]

  115. Effect of concentrating the virus-rich 2-200 nm size fraction of seawater on the formation of algal flocs (marine snow). Peduzzi, P., Weinbauer, M.G. (1993). Limnol. Oceanogr. 87:105-112. [TOP OF PAGE]

  116. The submicron size fraction of seawater containing high numbers of virus particles as bioactive agent in unicellular plankton community successions. Peduzzi, P., Weinbauer, M.G. (1993). Jour. Plankt. Res. 15:1375-1386. [TOP OF PAGE]

  117. Transport of bromide, simazine, and MS-2 coliphage in a lysimeter containing undisturbed, unsaturated soil. Poletika, N.N., Jury, W.A. (1993). Agronomy Abstracts 85:215 [TOP OF PAGE]

  118. Calibrating estimates of phage-induced mortality in marine bacteria ultrastructural studies of marine bacteriophage development from one-step growth experimetns. Proctor, L.M., Okubo, A., Fuhrman, J.A. (1993). Microb. Ecol. 25:161-182. The timing of lytic phase development and the relationship between host generation times and latent periods were investigated by electron microscopy of one-step growth experiments in two strains of marine Vibrio species. Results were used in a correction factor developed to interpret field studies of phage-infected marine bacteria. Both the number of mature phase per average cell section and the percentage of cells with mature phase increased exponentially by 73-86% into the latent periods. Assuming that bacterial infection and lysis take place continually in the ocean, conversion factors for relating the percentage of visibly infected bacteria to the total percentage of the bacterial community that are phage-infected were calculated as 3.70-7.14. When this range of factors was applied to previously-collected field data Proctor LM, Fuhrman JA (1990) Nature (Lond) 343:60-2; Proctor LM, Fuhrman JA (1991) Mar Ecol Prog Ser 69:133-142 from 3 to 31% of the free-living bacteria and 3 to 26% of particulate-associated bacteria appeared to be phage-infected at any given time. Based upon a steady-state model in which half the daughter cells survive to divide again, the percent of total mortality would be twice the total percentage of phage-infected cells. From 6 to 62% and from 6 to 52% of mortality for the free-living and particulate-associated bacterial community, respectively, may be due to viruses. [TOP OF PAGE]

  119. Versatile suicide vectors which allow direct selection for gene replacement in gram-negative bacteria. Quandt, J., Hynes, M.F. (1993). Gene (Amsterdam) 127:15-21. A set of vector plasmids which greatly facilitate gene replacement and reverse genetics in many Gram-negative bacteria was constructed. These vectors are based on the P15A origin of replication (ori) and incorporate sacB from Bacillus subtilis, which is inducible by sucrose and is lethal when expressed in Gram-negative bacteria. The vectors also have a convenient antibiotic-resistance marker (gentamicin resistance) and the lacZ-alpha system which allows blue/white selection of cloned fragments. Three different multiple cloning sites, allowing several distinct cloning and gene replacement strategies, are available in the 5' end of lacZ on different vectors. One of these cloning sites, which we synthesised, contains only a NotI-SmaI-NotI sequence; this allows access to most of the restriction sites within the cloned fragment for the purpose of insertion of various cassettes and interposons. The vectors carry the mob region from the broad-host-range plasmid RP4 and are thus mobilisable by conjugation into a wide range of Gram-negative bacteria; since they will not replicate in bacteria other than enterobacteria, they function as 'suicide' vectors. Variants of the vectors carrying the phage lambda cos site were also constructed. We have used these vectors to carry out gene replacement experiments in the fixN region of Rhizobium leguminosarum and have demonstrated that they are extremely useful in eliminating long and tedious screening procedures. [TOP OF PAGE]

  120. Dramatic improvements in viral inactivation with brominated psoralens, naphthalenes and anthracenes. Rai, S., Kasturi, C., Grayzar, J., Platz, M.S., Goodrich, R.P., Yerram, N.R., Wong, V., Tay-Goodrich, B.H. (1993). PHOTOCHEMISTRY AND PHOTOBIOLOGY 58:59-65. Amino or polyamino derivatives of naphthalene (N-H), anthracene (A-H) and 8-alkoxypsoralen (PSR-H) were prepared along with their monobrominated analogs (N-Br, A-Br and PSR-Br). The ammonium salts of these compounds are all water soluble and bind strongly to calf thymus DNA and to lambda phage, a double-helical DNA, protein-coated virus. Binding of the sensitizer to DNA occurs, presumably by a mixture of hydrophobic, intercalative and electrostatic interactions. Relative binding constants to calf thymus DNA and to lambda phage were measured by the ethidium bromide fluorescence quenching assay. In general the brominated analogs bind more tightly to calf thymus DNA and to the virus than to the nonhalogenated analogs. It is demonstrated that the brominated aromatics a