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N V Volozhantsev

Publications and source records attributed to N V Volozhantsev.

13 recordsLinked to original sources
PubMed2004

Distribution and characterization of Campylobacter spp. from Russian poultry.

The distribution of Campylobacter spp. on 13 poultry farms (broiler chicken, quail, pheasant, peacock, and turkey) from eight regions (Vladimir, Vologda, Voronezh, Kaluga, Liptsk, Moscow, Orenburg, and Orel) in Russia was surveyed. Intestinal materials were plated onto Campylobacter-selective medium and plates were incubated microaerobically at 42 degrees C for 24 or 48 h. Identification was based on colonial morphology, microscopic examination, and biochemical tests; latex agglutination assays were used for confirmation. In total, 116 isolates were derived from 370 samples. Isolation rates were similar, regardless of whether the birds were from small or large broiler production farms. Susceptibility of 48 representative (from these production sources) strains of Campylobacter spp. to 38 antimicrobial compounds was determined by disk diffusion assays. All strains tested were sensitive to amikacin, gentamycin, sisomycin, chloramphenicol, imipenem, oleandomycin, erythromycin, azitromycin, and ampicillin. The strains were also sensitive to 100 microg/disk of carbenicillin, fluoroquinolones, and to nitrofurans. Fluoroquinolone sensitivity was most notable and may be related to its limited application in poultry production within Russia. Hippurate and ribosomal RNA gene primers were developed and used to distinguish Campylobacter jejuni and Campylobacter coli and to provide a measure of strain discrimination. The combination of PCR analysis and randomly amplified polymorphic DNA (RAPD) typing were conducted for selected isolates. The various poultry species and the different locations yielded Campylobacter isolates with discrete randomly amplified polymorphic DNA patterns. The distribution and substantial diversity of Campylobacter spp. isolates appears similar to that previously reported in other countries.

Animals↗
PubMed1997

[Effect of TRA-system of plasmids RP4 and R68.45 on pseudomonas mallei virulence].

In Pseudomonas mallei, spontaneous mutants (Tra- mutants) of the plasmids RP4 and R68.45, losing the ability to transfer at conjugation are formed. The plasmids RP4 and R68.45 with Tra(+)-phenotype caused a decrease in P. mallei virulence for laboratory animals. At the same time, Tra- mutants of these plasmids do not affect P. mallei virulence. The insertion of DNA fragment of about 1900 bp into the plasmid transfer gene regions (tra-2-tra-3) gave rise to RP4 and R68.45 tra mutations detectable on examination.

Animals↗
PubMed1983

[Integration of plasmid RP1 with the chromosome of Escherichia coli K-12 recA. 2 classes of Hfr strains].

Integration of broad host range RP1 plasmid into the chromosome of Escherichia coli K-12 recA- cells has been studied. Using temperature-sensitive for replication plasmids pVD1 and pVD3, the derivatives of RP1, it has been shown that integration of RP1 into the bacterial chromosome results in formation of two classes of Hfr strains. Properties of these Hfrs have been examined. From the data obtained, it has been concluded that the plasmid integration and formation of one of the Hfrs classes appear to be mediated by transposon Tn1 residing on RP1. The other class of Hfr strains is formed due to a stable integration of RP1. In the course of analysis of R+ transconjugants arising at low frequency in crosses between stable Hfrs and E. coli rec+ recipients, it has been found that the significant part of them contain plasmid-chromosome hybrids (R-prim plasmids). On the basis of the latter results, a new simple method for R' plasmids selection has been proposed. Using restriction endonuclease analysis, the structure of plasmids that were excised from chromosomes of the stable Hfr strains and were comparable in their size to RP1, has been investigated. Probable mechanisms of the stable Hfr strains formation are discussed.

Chromosomes, Bacterial↗
PubMed1982

[Formation of stable Hfr strains in R factor RP1 integration with the chromosome of E. coli K12 recA and their use for R-plasmid selection].

Analysis of thermoindependent derivatives of E. coli K12 JC1553 recA (p VD1) carrying a replication thermostable mutant pVD1 of R factor RP1 IncP Ap Km Tc showed that formation of about 5 per cent of them was associated with stable integration of the plasmid with the bacterial chromosome. The respective bacteria had the following features: (1) preserved all the markers of plasmid pVD1, (2) according to the data of the electrophoretic analysis had no extrachromosomal DNA on prolonged cultivation under nonselective conditions, (3) were effective donors of the chromosomal genes, (4) had a low rate of the plasmid marker transfer on crossing with R- recipient. The latter feature was suggested to be used as a test for identification of stable Hfr strains. Investigation of the properties of the transconjugants obtained on crossing of stable Hfr strains with R-recipients rec+ showed that same of them had plasmid DNA with a higher molecular mass as compared to that of plasmid pVD1 DNA. The presence of this DNA was connected with formation of R' plasmid as a result of an irregular exclusion of plasmid pVD1 from the chromosome of stable Hfr bacteria. On the basis of the results a simple method was proposed for selection of R' plasmids having a number of advantages over the classical ones. The perspectives of using thermostable derivatives of RP1 for cloning the chromosome genes are discussed.

Chromosomes, Bacterial↗
PubMed1980

[Restriction and electron microscopic analyses of deletion derivatives thermosensitive with respect to maintaining plasmid pEG1].

Temperature-independent deletion mutants of temperature-sensitive in self-maintenance plasmid pEG-1, derived from R-factor RP4, are mapped using the restriction endonucleases PstI, SmaI, EcoRI, BamHI and the heteroduplex analysis. The pEG1 derivatives under study are found to have deletions in the area of ampicillin transposon Tn1 and nearby genes. The left and the right ends of these deletions boundaries are localized between 37.5 MD and 7.6 MD in the RP4 map. Thus far, the area of plasmid RP4 (37.5-7.6 MD) with Tn1 and, presumably, inc gene(s) in it does not have any genes needed for stable maintenance of R-factor. A conclusion is made that the gene RP4, which carries the mutation determining thermosensitive character of pEG1 maintenance and of inhibition of the cell growth, is localized between the EcoRI site and transposon Tn1 at a distance less than 1.0 MD from the latter.

DNA Restriction Enzymes↗
PubMed1980

[Isolation and characteristics of deletion mutants of thermosensitive plasmid pEG1].

Phenotypic revertants of temperature-sensitive in self-maintenance plasmid pEG1 derived from R-factor RP4 were studied. The study indicated a sertain part of them to be variants without ampicillin resistance. The frequency of pEG1 ampicillin sensitive (Aps) derivatives is about 5.10(-7) and does not depend on the recA gene product. The Aps-derivatives of pEG1 plasmid can be classified in two phenotypic groups. The first group is temperature-independent and does not inhibit the growth of host cells by non-permissive temperature (43 degrees C). Agarose gel electrophoresis has revealed that plasmids of this group occur as a result of deletions in plasmid pEG1. The other group of Aps-derivatives still possess the property to be eliminated at 43 degrees C and they inhibit the growth of bacterial cells like pEG1. Agarose gel has demonstrated that some of them are deletion mutants while others are quite similar to pEG1 plasmid. The data obtained in the course of study of deletion mutants make it possible to suppose that the presence of gene with temperature sensitive mutation in pEG1 is not necessary for stable maintenance of R-factor.

Ampicillin↗
PubMed1979

[Incorporation of the ampicillin resistance transposon into the Escherichia coli K-12 chromosome and into plasmids].

The mutant pEG1 of R-factor RP4 with temperature-sensitive defect in replication, carrying a transposable ampicillin resistance element Tn1 was used to define the frequency of insertion of this element into Escherichia coli K-12 chromosome and some other plasmids. Our results indicate that the frequency of colony forming by bacteria with pEG1-factor on ampicillin medium in non-permissive conditions corresponds to the frequency of Tn1 insertion into bacterial chromosome or some other plasmid (in case when the strains are carrying a second plasmid). The frequency of Tn1 insertion into the chromosome is about 4.10(-4). The defect in recA gene produce no serious change in the frequency of Tn1 insertion into the bacterial chromosome. The translocation of Tn1 element from pEG1-factor to R483, R6 and ColE1 plasmids occurs at 10 to 100-fold-higher frequency than from the plasmid to the chromosome. The insertion of Tn1 into the F'-factor KLF10 and R-factor R64-11 occurs at far lower frequency than that to plasmids R6, R483, or ColE1.

Ampicillin↗
PubMed1978

[RP4 factor integration with E. coli chromosome].

Integration of R-factor RP4 with the chromosome of E. coli was studied with the use of replication thermosensitive mutant pEG1 of this factor. It was found that the frequency of integration of factor pEG1 containing the ampicillin transposone Tn1 with the chromosome of bacteria JC411 carrying transposone Tn1 previously inserted into it was very high and markedly exceeded that of its insertion into the same chromosome but not carrying this transposone. The frequency of factor pEG1 insertion into the chromosome of bacteria JC 1553 rec A defective with respect to genetic recombination was less than 2.10(-5) and did not depend on the presence of transposone Tn1 in it. Probably, insertion of factor RP4 into the bacterial chromosome may be realized through the rec A-dependent process of recombination between transposone Tn1 previously translocated into the chromosome and the same transposone contained in R-factor.

Ampicillin↗
PubMedDate not supplied

[Transformation of pathogenic pseudomonas by plasmid DNA].

The possibility has been shown of the genetical transformation of Pseudomonas mallei strains by the purified DNA of the plasmids RSF1010, pES154, pBS222 and pBR325. The frequency of transformation varied from 1.2 x 10(1) to 2.0 x 10(2) depending on the plasmid DNA and transformation technique used in the experiments. Pseudomonas pseudomallei cells could not be transformed by the methods described in the paper.

Burkholderia pseudomallei↗
PubMedDate not supplied

[Corynebacterium diphtheriae nontoxigenic strain carrying the gene of diphtheria toxin].

Among 828 C. diphtheriae nontoxigenic cultures isolated in different region of Russia in 1994-2002, 114 cultures (13.8%) had the gene of diphtheria toxin (gene tox) and were thus called nontoxigenic tox-carrying (NTTC) strains. All NTTC strains were found to belong to biovar mitis and formed neither normal, nor "defective" diphtheria toxin. The most of NTTC strains (94%) belonged to ribotype "Moskva", not occurring among C. diphtheriae toxigenic strains. The incapacity of NNTC strains of forming diphtheria toxin was caused by mutation: the deletion of one nucleotide which led to the shift of the open reading frame and to the formation of the stop codon. The results of these studies are indicative of the fact that a sufficiently homogeneous and isolated group of C. diphtheriae nontoxigenic strains is spread in Russia. These strains carry the nonexpressing gene of diphtheria toxin and are of no epidemic importance in diphtheria infection.

Codon, Terminator↗
PubMedDate not supplied

[Identification of the bacterium Pseudomonas mallei using Pseudomonas pseudomallei bacteriophages].

Phage production by Pseudomonas pseudomallei and Pseudomonas mallei strains has been studied. 32 P. pseudomallei bacteriophages have been isolated. Their spectrum of lytic action against P. pseudomallei, P. mallei and other Pseudomonas sp. has been defined. It has been shown that P. pseudomallei bacteriophages PP19, PP23, PP33 may be used for identification P. mallei among related Pseudomonas.

Burkholderia pseudomallei↗
PubMedDate not supplied

[Transduction of Pseudomonas mallei bacteria].

The transducing ability of 17 Pseudomonas pseudomallei bacteriophages has been studied. Five of them were found to be capable of transducing the transposon Tn7 markers TpR, SmR into the strain Pseudomonas mallei C-5. The transduced bacterial recipients became lysogenic and acquired resistance to trimethoprim and streptomycin. Transduction of transposon Tn7 has been confirmed by DNA-DNA hybridization.

DNA Transposable Elements↗