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At least 19 recordsLinked to original sources
PubMed1985

Control of gene expression in P2-related coliphages: the in vitro transcription pattern of coliphage 186.

Transcription in vitro of coliphage 186 DNA generated four transcripts. The most abundant transcript was that of the late control gene B and an equivalent transcript was identified for the closely related phage P2. A second transcript was from the rightward promoter at 75% and predicted to be under CI repressor control. The remaining two transcripts initiated from the one promoter located at 95% and are apparently under LexA control in vivo. The significance of these transcripts is discussed in relation to coliphage 186.

Base Sequence↗
PubMed1992

Partial characterization of coliphage WPK and a comparison with coliphage T3.

Coliphage WPK was originally isolated from sewage in Kiel, Germany, because its plaque diameter continued to expand for days. Electron microscopy revealed an isometric capsid with dimensions of 54 nm between opposite apices, and a short, noncontractile tail 16 nm long, placing phage WPK into morphogroup C1. The nucleic acid of phage WPK was linear double stranded DNA. The host ranges of phages WPK and T3 were identical. Of ten E. coli strains tested for host range, two were resistant and of eighteen other Enterobacteriaceae only four were susceptible. Seven gram-negative species which are not members of the Enterobacteriaceae were refractory. However, there were differences in plaque morphology and plaque expansion between the two phages. Phage T3 plaques expanded for at least seven days on E. coli B only, while phage WPK plaques expanded for at least seven days on four strains of E. coli. The buoyant density of WPK, determined by isopycnic density gradient centrifugation in CsCl, was 1,508 g/ml which was significantly different than that of T3 at 1.493 g/ml (P less than 0.05). Phage-encoded proteins were examined for each phage using [35S]methionine incorporation, SDS-PAGE, and autoradiography. Of thirty proteins identified in phage WPK and twenty-eight in phage T3, only fourteen were of the same size in both. We concluded that phage WPK was distinct, but related to T3.

Coliphages↗
PubMedDate not supplied

phi gamma: A coliphage coliphage related to, but distinct from the phi 80 virion.

The coliphage phi gamma, though capable of genetic recombination with phi 80, is morphologically distinct from the phi 80 virion. It has a prolate head (58.4 X 46.7 nm) bearing a tail (143 nm) which is strikingly flexible. On the basis of their buoyant density in CsC1, both infectious and transducing phi gamma particles form a single population. This density value is slightly higher than that of the phi 80 virion. The phi gamma chromosome is a double-stranded linear DNA molecule of 13.4 mum in length (corresponding mol. wt.: 27.6 X 10(6)). From its melting temperature and its buoyant density in CsC1, phi gamma DNA appears to have a base composition very close to that of Escherichia coli DNA.

Capsid↗
PubMed1986

Methodology for enumeration of coliphages in foods.

The effects of eluent composition, pH, and chaotropic agents on the recovery of T2, MS2, and indigenous coliphages from various foods were investigated. Additionally, methods of sample suspension and clarification were evaluated for coliphage recovery and application to various foods. Clarified sample suspensions were assayed for coliphages with a modified agar layer technique and appropriate Escherichia coli hosts. Centrifugation and polypropylene mesh filtration were more rapid and effective than glass wool filtration for clarification of sample suspensions and subsequent recovery of coliphages. Blending, stomaching, and shaking procedures were generally comparable for sample liquefaction and release of coliphages from foods. Complex basal eluents, EC medium and 1% casein, were generally more effective than a less complex eluent, phosphate buffer, for elution of coliphages from foods. For most foods, incorporation of sodium chloride or chaotropic agents, i.e., sodium trichloroacetate, urea, Tween 80, Triton X-100, and sodium nitrate, into basal eluents did not enhance recovery of coliphages. Indigenous coliphage recovery was not affected by sample suspension pH over a range of 6.0 to 9.0. With an optimal procedure, i.e., EC medium eluent, blending, and centrifugation, the recovery of T2 and MS2 ranged from 48 to 81% and from 58 to 100%, respectively, depending on the food type.

Animals↗
PubMed1988

Animal viruses, coliphages, and bacteria in aerosols and wastewater at a spray irrigation site.

Aerosol samples collected at the Muskegon County Wastewater Management System Number 1 spray irrigation site in Michigan by using the Army prototype XM2 Biological Sampler/Collector were examined for the presence of animal viruses, coliphages, and bacteria. Air samples, collected in Earle lactalbumen hydrolysate, and wastewater samples were filtered through a 0.45- and 1.2-micron membrane filter sandwich, pretreated with 10% beef extract (pH 7.0), and assayed for animal viruses by the plaque method on Buffalo green monkey kidney cells. Untreated air and wastewater samples were assayed for coliphages by the soft agar overlay method with three Escherichia coli hosts (ATCC 13706, 15597, and 11303) and for bacteria by the heterotrophic plate count method. Filtered air samples were assayed for coliphages by the most-probable-number method with the same three hosts. Although no animal viruses were detected in the aerosol samples, coliphages and bacteria were recovered. E. coli ATCC 13706 coliphage were recovered more often and in greater numbers than either of the other two types of coliphages. Concentrations of animal viruses, coliphages, and bacteria detected in the raw influent decreased as the wastewater was aerated and stored in the lagoons. No animal viruses were detected in the wastewater at the pump station just before distribution to the spray irrigation rigs. The most-probable-number method was more sensitive and consistent than the overlay procedure in detecting low levels of coliphages in air samples.

Aerosols↗
PubMed1990

Tissue distribution of a coliphage and Escherichia coli in mussels after contamination and depuration.

Experiments were undertaken to determine the tissue distribution of Escherichia coli and a coliphage after contamination of the common mussel (Mytilus edulis). Mussels were contaminated with high levels of feces-associated E. coli and a 22-nm icosahedral coliphage over a 2-day period in a flowing-seawater facility. After contamination, individual tissues were carefully dissected and assayed for E. coli and the coliphage. Contaminated mussels were also analyzed to determine the tissue distribution of the contaminants after 24- and 48-h depuration periods. The majority of each contaminant was located in the digestive tract (94 and 89% of E. coli and coliphage, respectively). Decreasing concentrations were found in the gills and labial palps, foot and muscles, mantle lobes, and hemolymph. Our results indicate that contamination above levels in water occurred only in the digestive tract. Contaminated mussels were depurated in a commercial-scale recirculating UV depuration system over a 48-h period. The percent reductions of E. coli occurred in the following order: digestive tract, hemolymph, foot and muscles, mantle lobes, and gills and labial palps. The percent reductions of the coliphage were different, occurring in the following order: hemolymph, foot and muscles, gills and labial palps, mantle lobes, and digestive tract. Our results clearly demonstrate that E. coli and the coliphage are differentially eliminated from the digestive tract. The two microorganisms are eliminated at similar rates from the remaining tissues. Our results also clearly show that the most significant coliphage retention after depuration for 48 h is in the digestive tract. Thus, conventional depuration practices are inappropriate for efficient virus elimination from mussels.

Animals↗
PubMed1988

[Quantitative studies of the elimination of coliphages and other fecal indicators during wastewater treatment].

Concentrations of coliphages, coliforms, enterococci and fluorescent Pseudomonas were monitored in several wastewater purification steps of the treatment plant Wolfenbüttel during one year. Their number varied widely during the investigation period, but was independent of seasons. In the course of sewage treatment, including primary settling, activated sludge purification, simultaneous precipitation, trickling filters and oxidation pond, the concentration of indicators decreased gradually. The coliphages were most resistant, exhibiting only a decimal elimination value of 1.7 log10 units as compared to the bacterial indicators with elimination values ranging between 2.4 and 2.8 log10 units in the whole process. The most efficient purification step revealed to be the activated sludge procedure including simultaneous phosphate precipitation with iron hydroxides and sedimentation. On an average 1.7% of the coliphages present in raw sewage or 9.8.10.11 phages were discharged into the river Oker everyday, 0.64% remained in the sludge. Numbers of indicators in the water of the oxidation pond and those seeded into river water were continuously reduced during 3 days. Also in these laboratory experiments, the coliphages were more resistant than the bacteria, but no evidence was found to support the view that coliphages play a role in the reduction of the number of coliform bacteria. Even after addition of peptone which stimulated growth of E. coli the coliphages were inactivated more rapidly. The behaviour of coliphages during the purification process is compared with literature data about enteroviruses.

Bacteria↗
PubMed1985

Comparison of selective media for assay of coliphages in sewage effluent and lake water.

Selective media, including EC medium, gram-negative broth, nutrient broth (with 0.05% sodium deoxycholate), and lactose broth (with 0.05% sodium deoxycholate), as well as nonselective nutrient and lactose broths, were compared for the enumeration of coliphages by the agar layer method from activated-sludge effluent and eutrophic-lake water from a lake receiving treated sewage effluent. Samples were plated directly or after chloroform treatment with Escherichia coli B, E. coli C, or a mixed host of both E. coli B and C. With the exception of gram-negative broth, direct assays of all samples with the selective media generally resulted in significantly higher (P less than 0.05) recoveries of coliphages than did assays of chloroform-treated samples with nutrient broth medium regardless of the host used. In addition, chloroform pretreatment resulted in decreased recovery of coliphages with each selective medium in most analyses. The highest recoveries of coliphages from all samples with each host, except lake water with E. coli C, were obtained by direct assay on EC medium. The selectivity of the EC and gram-negative media resulted in suppression of bacterial interference on direct assay plates comparable to that observed in nutrient agar medium with chloroform-treated samples. The use of certain selective media for the direct assay of environmental materials for coliphage may enhance the recovery of coliphages and obviate bacterial decontamination procedures.

Chloroform↗
PubMed1989

Differential depuration of poliovirus, Escherichia coli, and a coliphage by the common mussel, Mytilus edulis.

The elimination of sewage effluent-associated poliovirus, Escherichia coli, and a 22-nm icosahedral coliphage by the common mussel, Mytilus edulis, was studied. Both laboratory-and commercial-scale recirculating, UV depuration systems were used in this study. In the laboratory system, the logarithms of the poliovirus, E. coli, and coliphage levels were reduced by 1.86, 2.9, and 2.16, respectively, within 52 h of depuration. The relative patterns and rates of elimination of the three organisms suggest that they are eliminated from mussels by different mechanisms during depuration under suitable conditions. Poliovirus was not included in experiments undertaken in the commercial-scale depuration system. The differences in the relative rates and patterns of elimination were maintained for E. coli and coliphage in this system, with the logarithm of the E. coli levels being reduced by 3.18 and the logarithm of the coliphage levels being reduced by 0.87. The results from both depuration systems suggest that E. coli is an inappropriate indicator of the efficiency of virus elimination during depuration. The coliphage used appears to be a more representative indicator. Depuration under stressful conditions appeared to have a negligible affect on poliovirus and coliphage elimination rates from mussels. However, the rate and pattern of E. coli elimination were dramatically affected by these conditions. Therefore, monitoring E. coli counts might prove useful in ensuring that mussels are functioning well during depuration.

Animals↗
PubMed1991

Comparative inactivation of poliovirus type 3 and MS2 coliphage in demand-free phosphate buffer by using ozone.

MS2 coliphage (ATCC 15597-B1) has been proposed by the U.S. Environmental Protection Agency as a surrogate for enteric viruses to determine the engineering requirements of chemical disinfection systems on the basis of previous experience with chlorine. The objective of this study was to determine whether MS2 coliphage was a suitable indicator for the inactivation of enteric viruses when ozone disinfection systems were used. Bench-scale experiments were conducted in 2-liter-batch shrinking reactors containing ozone demand-free 0.05 M phosphate buffer (pH 6.9) at 22 degrees C. Ozone was added as a side stream from a concentrated stock solution. It was found that an ozone residual of less than 40 micrograms/liter at the end of 20 s inactivated greater than 99.99% of MS2 coliphage in the demand-free buffer. When MS2 was compared directly with poliovirus type 3 in paired experiments, 1.6 log units more inactivation was observed with MS2 coliphage than with poliovirus type 3. It was concluded that the use of MS2 coliphage as a surrogate organism for studies of enteric virus with ozone disinfection systems overestimated the inactivation of enteric viruses. It is recommended that the regulatory agencies evaluate their recommendations for using MS2 coliphage as an indicator of enteric viruses.

Buffers↗
PubMed1991

Fate of human enteric viruses, coliphages, and Clostridium perfringens during drinking-water treatment.

The elimination of human enteric viruses, coliphages, and Clostridium perfringens was studied during a conventional complete drinking-water treatment process. The respective concentrations (geometric mean) of these microorganisms in 100-L samples of river water were, respectively, as follows: viruses, 79 mpniu (most probable number of infectious units) per 100 L, coliphages, 6565 pfu (plaque-forming units) per 100 L. and clostridia, 11,349 cfu (colony-forming units) per 100 L. After predisinfection, flocculation with alum, and settling, human enteric viruses were not detected in any of the 100-L samples (less than 4 mpniu/100 L), but coliphages were detected in 7 of 14 samples and clostridia in 15 of 16 samples. In filtered water samples, human enteric viruses were detected in 2 of 31 samples, coliphages in 10 of 33, and clostridia in 17 of 33. Finished water was free of human enteric viruses (0/162 samples), but coliphages were detected in one sample (1.5 pfu/100 L) and clostridia in three, at 1.0, 4.1, and 7.0 cfu/100 L. It thus appears that coliphages and clostridia, which are present in larger numbers than viruses in river water and which may have similar resistance to drinking-water treatments, may be useful for estimating the level of treatment attained when large volumes of water (1000 L or greater) are sampled.

Clostridium perfringens↗
PubMedDate not supplied

[Coliphages, viral indicators of contamination].

This paper illustrates the importance of coliphages, which are specific bacteriophages for Escherichia coli strains, as viral indicators, and suggests the usefulness of a routine coliphage search in the detection of viral contamination. The samples studied consisted of 57 surface water, (46 of sea water and 11 of river water), 2 of mud taken from biological treatment plants and 3 samples of sludge. The results revealed that coliphages can be considered valid indicators of viral contamination as they show a good response to the general standards established for indicators. In particular: they are found in sludge (both untreated and treated) and in surface water (both river and sea) in higher concentrations than those of enterovirus; they show greater resistance than bacterial indicators to disinfection as, in different experimental conditions, the drop in the level does not exceed orders of magnitude they are relatively simple to identify, and are easily quantifiable by means of the MPN method, with the result that they can be used for the management of water resources. As regards the possible use of coliphages for the control of the necessary qualitative requisites of sea water for bathing, the relation with fecal coli enables us to make an assessment of coliphages corresponding to 100 fecal coli/100 ml. This levels is equivalent to 0.95 so that a suitable guide line for water for bathing purposes could for example be established at 10 coliphages/1. Although coliphages may be considered good indicators of viral contamination this clearly does not mean that they can replace classic bacterial indicators but rather, that they can provide useful additional information, particularly in those cases where a rapid drop in bacterial content may conceal high risk health and hygiene conditions.

Bacteria↗
PubMed1988

Incidence of coliphage in potable water supplies.

Samples of drinking water from different sources in greater Cairo, Egypt, and bottled drinking water were tested for total coliform, fecal coliform, and coliphage populations. Of the 147 samples tested, 4 samples were positive for both total coliforms and coliphage, 65 samples were negative for total coliforms, fecal coliforms, and coliphage, and 78 samples were positive for coliphage and negative for total coliforms and fecal coliforms. The incidence of coliphage in these potable water supplies reflects the probability of human pathogenic virus survival in these waters also.

Coliphages↗