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PubMed1998

Fecal coliform-related bacterial and coliphage populations in five lakes of southeastern Spain.

Aerobic heterotrophic bacteria, fecal and total coliforms, fecal streptococci and coliphages were isolated from five protected lakes in the Antequera area of Spain over the time from January to March (1994-96). The water samples contained large number of heterotrophic bacteria (mean counts 0.2 to 5.0 x 10(7) cfu per 100 ml). Most of the lakes contained fecal streptococci and a relationship between streptococci and salinity of the water samples was established. Coliphages were isolated from lakes containing fecal coliform and these bacteria were taxonomically identified as E. coli. Coliform bacilli do not seem to be an adequate indicator of fecal pollution for these ephemeral small lakes.

Animals↗
PubMed1978

The behaviour of f2 coliphage in activated sludge treatment.

A model activated sludge treatment plant was used which was functionally very similar to a full-scale plant. It was inoculated with f2 coliphage and the titres of virus in the influent, the mixed liquor and the effluent were monitored regularly. The distribution of the virus in the solids and liquid fractions of the mixed liquor was in the ratio of 18:82 and 20.4% of the influent virus was recovered in the effluent. After inoculation was stopped the titre of virus in the solids fraction of the mixed liquor remained high and unaltered for up to 70 h, whereas the value for effluent reverted to the low background titre originally present. These results are discussed in relation to those reported for poliovirus and it is concluded that f2 coliphage is not a suitable model for studies of the behaviour of human enteroviruses.

Coliphages↗
PubMed2003

Bacterial host strains that support replication of somatic coliphages.

Somatic coliphages detected by Escherichia coli strain WG5 have been proposed as potential indicators of water quality. Their potential replication in the water environment is considered a drawback for their use as indicators. However, the contribution of replication outside the gut to the total numbers has never been quantified. It has not been determined either the fraction of bacterial strains that might support replication of phages detected by strain WG5 in the water environment. We examined the sensitivity of 291 host strains to 25 phages by streaking slants of the presumptive host strain onto an agar layer that contains bacteriophages, which gives a total of 7275 combinations (sensitivity tests). Only a 3.02% of the tests showed sensitivity. Additionally, six environmental strains were used as hosts to count phages in sewage and seawater. Phages isolated on these strains were used to infect strain WG5. The environmental strains detected 1 log10 fewer phages than strain WG5 in sewage and seawater. The fraction of phages that were detected by the six strains and that also infected strain WG5 ranged from < 0.07% to < 2.0% of the total amount of bacteriophages detected by strain WG5 in the same samples. Our results confirm that less than 3% of naturally occurring hosts support replication of phages infecting E. coli. We conclude that the contribution of replication to the number of somatic coliphages detected in the aquatic environment is negligible.

Coliphages↗
PubMed1973

Nucleotide sequences of similar size from the coliphage R17 genome.

A sequence of 33 nucleotides from the coliphage R17 RNA genome was determined. It constitutes the main component of a mixture of fragments that migrate together on electrophoresis in a separation according to molecular weight. Fragments of comparable chain length from 3' end of RNA from coliphage R17, from a region preceding and overlapping the coat-protein cistron ribosome binding site and from the beginning of the A-protein cistron, were also found and characterized. ;Hairpin'-like secondary structures are proposed for the longer fragments, one of which appears to have a tetranucleotide excised in the loop region.

Autoradiography↗
PubMed1999

Study of the potential relationship between the morphology of infectious somatic coliphages and their persistence in the environment.

The proportions of different morphological types of infectious somatic coliphages were determined in faecally polluted freshwaters. Myoviridae, followed by Siphoviridae, were the most frequently isolated morphological types in raw sewage, treated sewage and river water collected a few metres downstream from a sewage outfall. However, in river water collected further downstream from the pollution point, in river water after 'in situ' inactivation experiments and in chlorinated raw and treated sewage significant changes in the proportions of the different somatic coliphage morphological types occurred. In all cases, Siphoviridae, especially those with flexible and curled tails, became more abundant to the detriment of Myoviridae.

Caudovirales↗
PubMed1997

The dual role of Apl in prophage induction of coliphage 186.

In the present study we show that the Apl protein of the temperate coliphage 186 combines, in one protein, the activities of the coliphage lambda proteins Cro and Xis. We have shown previously that Apl represses both the lysogenic promoter, pL, and the major lytic promoter, pR, and is required for excision of the prophage. Apl binds at two locations on the phage chromosome, i.e. between pR and pL and at the phage-attachment site. Using an in vivo recombination assay, we now show that the role of Apl in excision is in the process itself and is not simply a consequence of repression of pR or pL. To study the repressive role of Apl at the switch promoters we isolated Apl-resistant operator mutants and used them to demonstrate a requirement for Apl in the efficient derepression of the lysogenic promoter during prophage induction. We conclude that Apl is both an excisionase and transcriptional repressor.

Attachment Sites, Microbiological↗
PubMed1979

Interaction of Escherichia coli RNA polymerase with promoters of several coliphage and plasmid DNAs.

The interaction of Escherichia coli RNA polymerase (nucleosidetriphosphate:RNA nucleotidyltransferase, EC 2.7.7.6) with restriction fragments obtained from various E. coli related DNAs was studied in vitro. The DNAs investigated included several coliphage genomes (T5, lambda, T7, fd) and plasmid DNAs (pML 21, pSC101). By using the nitrocellulose filter binding of the enzyme-DNA complexes, fragment-specific relative rates of complex formation as well as complex stabilities were determined. Promoter-specific relative rates of polymerase binding were derived from fragment-specific rates by taking into account the number of major binding sites for RNA polymerase within several DNAs. Estimates of the stability of complexes formed between some major binding sites and the enzyme were obtained by studying the rate of complex decay. Both characteristics--rate of complex formation and rate of decay--varied widely and independently of each other. The promoters reacting most efficiently with E. coli RNA polymerase were found in the early region of coliphage T5 whereas some promoters in pML 21, or for example, the lambda promoter PI, belong to signals binding the enzyme most slowly. Based on the second-order rate constant determined for the interaction of E. coli RNA polymerase with promoters of phage fd, the fastest promoters characterized so far reacted with rates in the order of 10(8) M-1s-1. The hierarchy of promoters established here is of interest from the viewpoint that promoter strength correlates with the rate of polymerase binding. Among the promoters studied here this rate spans a range of 2 orders of magnitude.

Base Sequence↗
PubMed1989

UV induction of coliphage 186: prophage induction as an SOS function.

Our results show that UV induction of the 186 prophage depends upon the phage function Tum, with the mutant phenotype of turbid plaques on mitomycin plates and the expression of which is controlled by the host LexA protein. Tum function, encoded near the right-hand end of the coliphage 186 chromosome, is under the control of promoter p95. This promoter is overlapped by a sequence closely related to the consensus sequence of the LexA-binding site. It is proposed that inactivation of LexA after UV irradiation (or by genetic means) leads to prophage induction by permitting expression of Tum which, by unknown means, induces prophage. This mechanism is basically different from that seen with the UV-inducible lambdoid coliphages, which are not regulated by LexA.

Base Sequence↗
PubMed2003

Removal of Encephalitozoon intestinalis, calicivirus, and coliphages by conventional drinking water treatment.

The removal of the Microsporidia, Encephalitozoon intestinalis, feline calicivirus and coliphages MS-2, PRD-1, and Fr were evaluated during conventional drinking water treatment in a pilot plant. The treatment consisted of coagulation, sedimentation, and mixed media filtration. Fr coliphage was removed the most (3.21 log), followed by feline calicivirus (3.05 log), E. coli (2.67 log), E. intestinalis (2.47 log), MS-2 (2.51 log). and PRD-1 (1.85 log). With the exception of PRD-1 the greatest removal of the viruses occurred during the flocculation step of the water treatment process.

Animals↗
PubMed1982

Coliphage BA14: a new relative of phage T7.

Coliphage BA14 was isolated from sewage and shown to be related to phages T7 and T3. It is similar to T3 in that it directs the synthesis of an S-adenosyl-methionine-cleaving enzyme (SAMase) early upon infection. However, it differs from all other known T7-related coliphages by the inability of its RNA polymerase (gene 1 product) to transcribe T7 DNA or T3 DNA. BA14, T7 and T3 also show marked differences in autoradiographic patterns of their gel-electrophoretically separated 35S-labelled intracellular phage proteins, restriction endonuclease HpaI cleavage patterns of their DNAs, and serological specificities of their infectious particles. Other distinctive features became apparent upon simultaneous mixed infection with BA14 and T7 or T3: inability of BA14 to produce genetic recombinants with either T7 or T3; lack of functional complementation between amber mutants of BA14 and T7 or T3; mutual exclusion and depression of the burst size of the mixedly infected cells.

Antigens, Viral↗
PubMed1977

The host-dependent restriction of growth of an RNA coliphage FI.

Phage FIC is a spontaneous host-dependent mutant of phage FI which is classified into the fourth group of RNA Escherichia coli phages (RNA coliphages). The mutant phage (FIC) grows normally in E. coli strain Q13 (permissive host), but poorly in strain A/lambda (non-permissive host) (9). Attempts to elucidate the regulatory mechanism of growth of the mutant phage in the non-permissive host revealed the following: (a) growth of the mutant phage was specifically restricted in E. coli strains that have certain suppressor genes for amber mutation; (b) the mutant phage RNA (FIC-RNA) could not produce progeny in the spheroplasts of the non-permissive host; (c) adsorption of the mutant phage to, and penetration of the mutant phage RNA into, the non-permissive host were normal; and (d) biosynthesis of the phage-specific late protein and RNA did not occur in the non-permissive host. Based on these results we conclude that phage FIC is a spontaneous azure-type mutant of the fourth group of RNA coliphage FI.

Adsorption↗
PubMed1980

Coliphage HK243: biological and physicochemical characteristics.

Coliphage HK243 can form plaques on Escherichia coli C and K-12, but not B. The plaques are 1-2 mm in diameter and are opaque areas which clear upon exposure to chloroform vapor. During one-step growth, the eclipse and the latent periods are 20 and 30 min, respectively. Phage-infected cells continue to produce cell-free plaque-forming units for as long as 80 min after the end of the latent period, although at high multiplicities of infection (MOI) most cells lyse. No lysogenic bacteria have been found among survivors, so HK243 is considered a virulent phage. Some of the cells surviving a high MOI challenge are maltose negative and resistant to both HK243 and coliphage lambda. This fact has made possible the isolation of lambda-resistant mutants of lambda-lysogens. However, no serological cross-reaction between the phages lambda and HK243 has been detected. Genetic data involving three essential loci and a locus controlling plaque morphology suggest a circular linkage map. The virions are tadpole-shaped with an icosahedral head 68 nm long which is attached to a flexible tail 131 nm long. The phage has a linear, duplex DNA genome of molecular weight approximately 44 x 10(6) and a base composition of 33% adenine, 31% thymine, 16% guanine, and 20% cytosine.

Coliphages↗
PubMed1983

Distribution of RNA coliphages in Senegal, Ghana, and Madagascar.

The distribution patterns of RNA coliphages (phages) in Senegal, Ghana, and Madagascar were investigated by collecting sewage samples from domestic drainage in November, 1980. In Senegal, among 65 sewage samples collected mainly from Dakar and its vicinity, 14 (22%) contained RNA phages (16 strains). By serological analysis, 13 of 16 strains were found to belong to group III. This is consistent with the distribution pattern of RNA coliphages in tropical and subtropical regions of Asia. In Ghana, however, among 106 samples collected from Accra, Suhum, and their vicinities, only seven (7%) contained RNA phages (seven strains) (groups I, II, and III [1:3:3]). In Madagascar, among 124 samples collected from Antananarivo, Moramanga, and their vicinities, seven (6%) contained RNA phages (seven strains) (groups I, II, III, and IV [1:1:1:4]). In spite of the low isolation frequency, it can be said that Madagascar appears to have a unique distribution pattern (abundance of group IV phages) which differs from that of any other countries we have examined. The generality of the distribution pattern of RNA phages in the tropical region (abundance of group III phages) was thus verified at least in Senegal.

Coliphages↗
PubMed1995

Detection of coliphages and enteroviruses in sewage and aerosol from an activated sludge wastewater treatment plant.

Coliphages and enteroviruses were monitored over 12 months in sewage and air adjacent to an activated sludge plant. Both showed temporal variation but the mean count of phages in enterovirus-positive samples was not significantly different from that in enterovirus-negative samples. Hence coliphages are not necessarily a good indicator of enteroviruses in sewage and aerosols.

Aerosols↗
PubMed1978

Role of lime treatment in the removal of bacteria, enteric viruses, and coliphages in a wastewater reclamation plant.

Lime flocculation/sedimentation in the first process unit of a 4,500-m3/day wastewater reclamation plant reduced numbers of microorganisms extensively when operated at pH 11.2. The efficiency was much less at lower pH values, and some bacteria even multiplied at pH 9.6. Data on reduction in the number of microorganisms in the lime treatment and subsequent units indicate that inactivation by hydroxide alkalinity plays an important role in the efficiency of lime treatment. Reductions in the numbers of enteric viruses were higher than those of coliphages, enterococci, and total plate and coliform bacteria, which indicate that lime treatment can be monitored by means of coliphage and conventional bacteriological tests. This paper illustrates the valuable role of high-pH lime treatment in reducing the load of pathogenic microorganisms on subsequent units, including ultimate disinfection processes, which is important in the multiple safety barrier concept of wastewater reclamation processes.

Bacteria↗
PubMed1978

Distribution of ribonucleic acid coliphages in south and east Asia.

We investigated the distribution of ribonucleic acid (RNA) coliphages in the Philippines, Singapore, Indonesia, India, and Thailand by collecting sewage samples from domestic drainage in November 1976. Of the 221 samples collected from domestic drainage, 50 contained RNA phages (52 strains). By serological analysis, 46 of the 52 strains were found to belong to group III. It can thus be said that the most prevalent RNA phages in Southeast Asia (at least, in the Philippines, Singapore, and Indonesia) were group III phages. Investigations of sewage samples collected from domestic drainage in Japan indicate that the most prevalent RNA phages in mainland Japan (north of Kyushu) are group II phages, whereas group III phages are predominant in the southern part of Japan (south of Amamiohshima Island). We therefore propose a borderline between Kyushu and Amamiohshima Island for the geographical distribution of RNA coliphages in the domestic drainage of South and East Asia. Moreover, one strain (ID2) was inactivated to some extent with the antisera of four groups of RNA phages. This is thought to be significant from the evolutionary viewpoint.

Coliphages↗
PubMed1978

Toxicity of zinc to fungi, bacteria, and coliphages: influence of chloride ions.

A 10 mM concentration of Zn2+ decreased the survival of Escherichia coli; enhanced the survival of Bacillus cereus; did not significantly affect the survival of Pseudomonas aeruginosa, Norcardia corallina, and T1, T7, P1, and phi80 coliphages; completely inhibited mycelial growth of Rhizoctonia solani; and reduced mycelial growth of Fusarium solani, Cunninghamella echinulata, Aspergillus niger, and Trichoderma viride. The toxicity of zinc to the fungi, bacteria, and coliphages was unaffected, lessened, or increased by the addition of high concentrations of NaCl. The increased toxicity of zinc in the presence of high concentrations of NaCl was not a result of a synergistic interaction between Zn2+ and elevated osmotic pressures but of the formation of complex anionic ZnCl species that exerted greater toxicities than did cationic Zn2+. Conversely, the decrease in zinc toxicity with increasing concentrations of NaCl probably reflected the decrease in the levels of Zn2+ due to the formation of Zn-Cl species, which was less inhibitory to these microbes than was Zn2+. A. niger tolerated higher concentrations of zinc in the presence of NaCl at 37 than at 25 degrees C.

Bacteria↗