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[Introduction of transpozon Tn9 to endogenic plasmids of Erwinia carotovora during lysogenization of cells by coliphage P1].

It has been shown that phage P1 of Escherichia coli is able not only to lysogenize the cells of Erwinia carotovora but also to be a source of transpozon Tn9 for mutagenesis of cryptic plasmids of this important phytopathogen. Since the amount of the introduction in one of plasmids pCA25::Tn9 is 3.8 kb, at an average, it is supposed that Tn9 is inherited as a double tandem structure. A convenient method is offered for selecting bacterial clones carrying the plasmid pCA25::Tn9 which is based on counterselection of P1-lysogens at high concentrations of chloramphenicol - 100-120 microg/ml.

Anti-Bacterial Agents↗
PubMed1980

Analysis of the in vitro synthesis of 5'-gamma-32P-labeled transcripts from coliphage lambda by gel electrophoresis, RNA-DNA hybridization, and RNase T1 digestion.

Phage lambda RNA was synthesized in vitro in the presence of [gamma-32P]ATP or GTP. The 12 S, 9 S, 8 S, 6 S, and 5 S transcripts were labeled specifically at the 5'-end with [gamma-32P]ATP, while [gamma-32P]GTP was incorporated at the 5'-end of the 4 S RNA. Transcription of lambda DNA at various salt concentrations was studied by three experimental methods: electrophoresis of the transcripts in polyacrylamide gels; hybridization of RNA to DNA restriction fragments transferred to nitrocellulose paper; and digestion of the transcripts with RNase T1 and analysis of the resulting 5'-end 32P-labeled oligonucleotides by 20% polyacrylamide gel electrophoresis. Transcription from promoters pL, pR, and p'R was maximal between 50 mM and 150 mM NaCl and diminished as the salt concentration was raised to 200 mM. RNA synthesis originating from p'R was predominant at all salt concentrations. The relative salt sensitivity of RNA synthesis was determined for these promoters and found to decrease in the order: pL > pR > p'R.

Bacteriophage lambda↗
PubMed1982

[Changes in the nature of the sensitivity of an E. coli M strain carrying Inc-group R plasmids, to coliphages T3 and T7].

After the transfer of prototype plasmids R6K (IncX), R387 (IncK), R27 (IncH1) and T (IncN) to E. coli M nalr the appearance of histidine-dependent mutants (R27, T), histidine-leucine-dependent mutants (R6K), methionine-proline-dependent mutants (R387) was observed among the resulting transconjugates. The mutations of E. coli M nalr R+ cells induced by the introduction of the plasmids were accompanied by the transformation of the cells from the S-form into the R-form. In contrast to the prototrophs E. coli M nalr, the auxotrophs carrying plasmids R6K, R27, T acquired sensitivity to phage T7, and the methionine-proline-dependent mutant became sensitive to phages T and T7. The above-mentioned plasmids rendered E. coli M cells capable of synthetizing the donor pili. But the adsorption of phages T3 and T7 on the auxotrophic cells, both with and without plasmids, occurred due to their interaction with the cell-wall receptors.

Adsorption↗
PubMed1981

Viruses and bacteriophages.

Many of the enteric viruses which are transmitted from person to person by the fecal-oral route are found in raw and treated wastewater, and because of their persistence under adverse conditions may also be found in slightly polluted waters. There is no routine examination procedure of water and wastewater for enteroviruses, mainly because of the cumbersome isolation techniques, high cost and the need for highly skilled laboratory personnel. Phages are specific to single species of bacteria, are known for many enteric bacteria, and are very often used for final identification of enteric pathogenic bacteria. Coliphages are prevalent in raw and treated sewage as well as in polluted water, where enteric viruses may also be found. Coliphages were often mentioned as possible viral indicators in polluted water. To be a perfect indicator, they should comply with minimum criteria as follows: (a) they should be present wherever human enteric viruses are present; (b) the coliphage numbers recovered should be equal to or larger than those of enteric viruses recovered; (c) the coliphages should be at least as resistant as enteric viruses to adverse environmental conditions; (d) isolation and quantification of the coliphage should be faster and less expensive than isolation of the enteroviruses. Comparative studies show that the coliphage to enterovirus ratio in wastewater is about 10(3):1. Levels of poliovirus 1 (attenuated) to coliphage f2 remained stable for a few months in oxidation pond effluents. f2 coliphage exhibited higher resistance to chlorination than poliovirus 1 (attenuated). When the two strains were kept in water of different quality, f2 survived longer. In addition, all coliphage counts were completed within 24 h. while those of enteroviruses required about a week. Results indicate very strongly that coliphages can be used as viral indicators and this is already the practice in a few European and other countries.

Coliphages↗
PubMed2003

A simple method to screen cilantro and parsley for fecal indicator viruses.

A protocol has been developed to process cilantro and parsley samples for male-specific coliphages. Coliphage recovery depended on the duration of peptone rinsing, and whether the products were intact or cut. After 60 min of rinsing with 0.1% peptone, 78% of spiked coliphages were recovered from intact cilantro samples, and 60% of the spiked coliphages were recovered from cut cilantro samples. The protocol was field tested on a limited scale using cilantro and parsley samples from six retail outlets using enrichment-based and quantitative coliphage assays. Of the 18 retail cilantro and parsley samples that were analyzed, 50% (9 of 18) of the cilantro samples were positive for male-specific coliphages using the enrichment-based assay compared to 39% (7 of 18) of the parsley samples. Using the quantitative coliphage assay, only 28% (5 of 18) of the cilantro samples were positive, and none of the parsley samples were positive. The number of male-specific coliphages ranged between 1 and 11 plaque-forming units per 10 g of cilantro samples. None of the samples was positive for Escherichia coli. The results suggest that simplified male-specific coliphage screening of herb samples is possible and that male-specific coliphages be used along with conventional bacteriological indicators to screen produce for presence of fecal contamination.

Coliphages↗
PubMed2002

Enteric bacteriophages as potential fecal indicators in ground beef and poultry meat.

Recovery efficiencies of enteric bacteriophages (F+ RNA coliphages, somatic coliphages, and Salmonella phages) as alternative fecal indicators were determined from ground beef and chicken breast meat using amino acid eluants (glycine and threonine) and a complex eluant (3% beef extract). Levels of F+ RNA coliphages (MS2, GA, Qbeta, FI, and SP), the somatic coliphage phiX174, and three environmental isolates of Salmonella phages (isolated from raw sewage) were assayed using three respective hosts: Escherichia coli Famp, E. coli C, and Salmonella Typhimurium. When 8% polyethylene glycol and 0.1 M NaCl were used to precipitate bacteriophages eluted with five different eluants, the highest recoveries of the three phage groups were with 0.5 M threonine and 0.25 M glycine-threonine. The average recoveries of F+ RNA coliphages, somatic coliphages, and the Salmonella phages from ground beef and chicken meat were 100, 69, and 65%, respectively, with threonine (0.5 M, pH 9.0) as the eluate. Of eight market food samples tested, F+ RNA coliphages were detected in five (63%) and somatic coliphages were detected in seven (88%). The overall detection sensitivity of the method was 3 PFU/100 g of ground beef or chicken meat. Levels of bacteriophages and bacterial indicators on chicken carcass surfaces were determined at identified critical control points at a poultry plant. Through the processing steps of evisceration, washing, and chilling, the levels of F+ RNA coliphages and fecal coliforms were reduced by 1.6 and 1.9 log10 PFU or CFU/100 g, respectively. F+ RNA coliphages and perhaps other enteric bacteriophages may be effective candidate indicators for monitoring the microbiological quality of meat, poultry, and perhaps other foods during processing. The bacteriophage concentration method developed provides a simple, rapid, and practical tool for the evaluation of fecal contamination levels in ground beef and processed chicken meat.

Animals↗
PubMed2003

Virus removal during simulated soil-aquifer treatment.

Removals of indigenous coliphage and seeded poliovirus type 1 during simulated soil-aquifer treatment were evaluated during transport of secondary effluent under unsaturated flow conditions in 1-m soil columns. Independent variables included soil type (river sand or sandy loam) and infiltration rate. Removal of coliphage was in all cases less than removal of poliovirus type 1 (strain LSc-2ab), supporting contentions that indigenous coliphage can act as a conservative indicator of groundwater contamination by viral pathogens of human origin. Coliphage retention was significantly more efficient (p<0.001) in the finer-grained sandy loam (93%) than in sand (76%). Increasing reactor detention time from 5 to 20 h increased coliphage attenuation from 70% to 99% in a 1-m sand column. There was a significant linear correlation (p=0.012) between log-transformed (fractional) coliphage concentration [log(C/C(0))] and reactor detention time. Re-mobilization of attached coliphage occurred during simulated rainfall using low-ionic-strength water. Inhibition of aerobic respiration resulted in significantly less efficient coliphage attenuation (p=0.033), suggesting the involvement of aerobic microorganisms in the survival/retention of this virus.

Aerobiosis↗
PubMed1965

DETERMINATION OF BASE RATIOS OF SIX RIBONUCLEIC ACID BACTERIOPHAGES SPECIFIC TO ESCHERICHIA COLI.

1. A method is described for the isolation of single-stranded-RNA coliphages. Two of the six RNA coliphages investigated were new strains. 2. The base ratios of six RNA coliphages were determined by labelling the host bacterium with [(32)P]-phosphate, purification of the radioactive coliphages and separation of 2',3'-ribonucleotides liberated by alkaline hydrolysis of the coliphage RNA. 3. All six of the coliphages were morphologically similar, contained single-stranded RNA, and had sedimentation coefficient 80+/-5s. 4. The six RNA coliphages fell into two distinct groups, both serologically and in terms of their RNA base ratios.

Adenine↗
PubMed2005

Bioaerosol emission rate and plume characteristics during land application of liquid class B biosolids.

This study investigated bioaerosol emission rates and plume characteristics of bioaerosols generated during land application of liquid Class B biosolids. In addition, it compared the rate of aerosolization of coliphages and total coliform bacteria during land application of liquid Class B biosolids to the rate of aerosolization during land application of groundwater inoculated with similar concentrations of Escherichia coli and coliphage MS2. Air samples were taken immediately downwind of a spray applicator as it applied liquid (approximately 8% solids) biosolids to farmland near Tucson, Arizona. Air samples were also collected immediately downwind of groundwater seeded with MS2 and E. coli applied to land in an identical manner. Air samples, collected with liquid impingers, were taken in horizontal and vertical alignment with respect to the passing spray applicator. Vertical and horizontal sample arrays made it possible to calculate the flux of microorganisms through a virtual plane of air samplers, located 2 m downwind of the passing spray applicator. Neither coliphages nor coliform bacteria were detected in air downwind of spray application of liquid Class B biosolids. Based on limits of detection for the methodology, the rate of aerosolization during land application of liquid biosolids was calculated to be less than 33 plaque forming units (PFU) of coliphage and 10 colony forming units (CFU) of coliform bacteria per meter traveled by the spray applicator. The rate of aerosolization during land application of seeded groundwater was found to be, on average, 2.02 x 10(3) CFU E. coli and 3.86 x 10(3) PFU MS2 aerosolized per meter traveled by the spray applicator. This is greater aerosolization than was observed during land application of biosolids. Because concentrations of coliphages and coliforms were similar in the liquid biosolids and the seeded water, itwas concluded that some property of biosolids reduces aerosolization of microorganisms relative to groundwater. Additional experiments utilizing a novel air sampling protocol showed that the duration of bioaerosol exposure immediately (2 m) downwind of biosolids spray application is brief and the plume of bioaerosols generated is discrete. Additional air samples showed that aerosolization of coliphages and coliform bacteria after liquid biosolids have been applied to land does not occur at detectable levels.

Aerosols↗