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Biomedical subjects

I V Domaradskiĭ

Publications and source records attributed to I V Domaradskiĭ.

At least 19 recordsLinked to original sources
PubMed1991

[Features of the interaction of Escherichia coli and Francisella tularensis RNA polymerases with hybrid plasmids bearing fragments of Francisella tularensis chromosomal DNA].

Hybrid plasmids containing the fragments of Francisella tularensis chromosomal DNA and capable of tet-gene expression both in Escherichia coli and Francisella tularensis cells were constructed. The regions of francisella chromosomal DNA binding the RNA-polymerases of Escherichia coli and Francisella tularensis were found by the electron microscopy technique. Interconnection of those regions with the expression of tet-gene of the hybrid plasmids was demonstrated.

Chromatography, Gel↗
PubMed1991

[Behavior of Sa plasmid in tularemia pathogen cells].

The genome of Sa plasmid is shown to be a subject of genetical rearrangements in Francisella tularensis cells. The rearrangements either result in plasmid integration into the host cell genome or intramolecular amplification of cat-gene with the subsequent excision and recombination of the derivative plasmids. Stable inheritance of the plasmid is registered after integration while plasmid elimination occurs in case of extrachromosomal localisation.

Chromosomes, Bacterial↗
PubMed1991

[Study of CAT gene expression in Sa and pC194 plasmids in Escherichia coli, Francisella tularensis, and Bacillus subtilis cells].

The unit activities were defined for chloramphenicol-acetyltransferases coded for by the cat-genes of the plasmids Sa and pC194 in Francisella tularensis, Escherichia coli and Bacillus subtilis cells. Francisella tularensis cells were shown to hold intermediate position between Escherichia coli and Bacillus subtilis cells in their ability to express the genes of the different taxonomic origin. The direct dependence was found between the dose of the gene coding for chloramphenicol-acetyltransferase synthesis and efficiency of the gene expression, minimal inhibiting concentration of the antibiotic and colony size on the media containing chloramphenicol.

Bacillus subtilis↗
PubMed1991

[Transfer of bacteriophage PRD1 genes into modified plasmid Sa of Escherichia coli and Francisella tularensis cells].

The donor specific bacteriophage PRDI has been shown to mediate the genes transfer into Escherichia coli and Francisella tularensis cell under certain conditions. It is necessary for the process that the recipient cells inherit the plasmids determining absorbtion of bacteriophages on the cellular surface while the transferred genes are able to be expressed. The frequencies of the tet-gene transfer from the plasmid pSKFT5 into Escherichia coli and Francisella tularensis 15 cells inheriting the plasmid Sa are, correspondingly, 10(-6) and 10(-7) clones per bacteriophage plaque.

Bacteriophages↗
PubMed1990

[What are toxins to microbes? (the role of toxins in bacterial ecology)].

The author attempts to answer two questions: whether the toxins, in particular the toxins having their specificity connected with enzymatic activity, are needed for microbial cell physiology and their significance for bacteria that are not the obligate parasites for warm blooded animals. The analysis of literary data supposes the toxins to be essential cellular metabolites since many of them participate in energy acquiring. Besides that a number of toxins is shown to be relevant to microbial life and to affect the micropredators, especially the monocellular organisms feeding the microbes. In connection with the above mentioned, special attention is paid to extrachromosomal location of many toxins genes relating them to bacteriocins. The possibility is not excluded that in the future the new toxins might come to be found having the enzymatic activities.

Bacteria↗
PubMed1988

[Fermentation of inositol by bacteria of the genus Salmonella].

The capacity for the fermentation of inositol varies in different Salmonella strains. At the same time this capacity forms the basis for the determination of biovars (e. g., in S. typhimurium) and sometimes serves as the only sign for distinguishing different Salmonella sero- and biovars (e. g., S. mission and S. isangi, etc.). The study of the capacity of wild Salmonella strains for the fermentation of inositol has revealed that the fermentation of inositol is controlled by chromosomal and, seemingly, plasmid genes. In the latter case the possibility of using this sign for the biochemical and epidemiological typing of Salmonella strains is questionable.

Fermentation↗
PubMed1987

[Detailed mapping of the Hly-region of the plasmid pHly241. Homology of the hemolysis determinants of plasmids pHly241 and pHly195].

Data on the hemolysin synthesis determined by the plasmid pHly241, belonging to the incompatibility group I2, and its derivatives are presented in this paper. The restriction analysis of the pHly241 plasmid has resulted in the detailed mapping of the hly determinant region in the plasmid. The substantial homology has been demonstrated between the regions of the plasmids pHly241 and pHly195 coding for hemolysin synthesis and excretion from the bacterial cell.

Base Sequence↗
PubMed1987

[The "side-effects" of plasmids (R-plasmids and virulence)].

Many plasmids affect the host cells. Their effects cannot be explained only by the expression of the well-known genes coding for antibioticresistance, bacteriocinogeny and hemolysis or the analogous genes (side-effects). The side effects are not characteristic of all plasmids operating under similar conditions. Forecasting of the side-effects inducikility by any definite plasmid is impossible now. Sometimes the same functions exert the contrary effects on the bacterial cell. The connection between the presence of plasmids, especially R-plasmids and the complex cellular property, virulence, is of great interest. Often, bacteria become less virulent obtaining the plasmids. Two possible reasons causing such an effect are discussed. The first one is a direct effect of plasmids on cellular physiology. The second reason is connected with population shifts caused by the fact that the cells with initial low virulence possess the recipient ability predominantly. The decreased virulence of bacteria harbouring R-plasmids, in authors opinion, is quite a natural phenomenon based on plasmid host cells adaptation to the existence in "the realm of antimicrobial agents".

Bacteria↗
PubMed1986

[Transposon-mediated integration of the RP1 plasmid into chromosomes of methylotrophic bacteria].

The homology region between the DNA of plasmid RP1ts::Tn601 and chromosome of the thermotolerant methylotrophic bacterium Methylobacterium sp. SKF240 has been constructed by transposon Tn601 translocation into the chromosome. The clones of Methylobacterium sp. SKF240 having integrated the plasmid RP1 into the chromosome have been obtained by conjugation on the basis of above mentioned genetic technique. The integration of plasmid RP1 into the chromosomal DNA of the methylotroph has been confirmed by the genetic and electrophoretic methods. Clones harbouring the integrated plasmid are able to transfer the chromosomal genes for methionine and isoleucine-valine synthesis to the recipient cells of P. aeruginosa PAO ML4262 by conjugation.

Chromosomes, Bacterial↗
PubMed1986

[New R-plasmids in strains of Serratia marcescens with multiple drug resistance].

In 4 S. marcescens polyresistant strains isolated from patients conjugative plasmids transferred to Escherichia coli have been detected. Two of these strains carry each one plasmid which codes resistance to 10 different antibiotics, including aminoglycosides which rarely occur in our country, and belongs to group IncC. The third strain is the host of 2 plasmids. One of them is similar to the above-mentioned 2 plasmids with respect to the incompatibility group and a set of markers, but additionally codes resistance to cephalosporins; the second plasmid has been determined as belonging to group IncM, unstable and capable of rendering the cells highly resistant only to aminoglycosides. And, finally, the fourth strain also carries 2 plasmids: one of them is unstable and belongs, supposedly, to group IncI alpha, and the second plasmid is stable and belongs to group IncM. The plasmid of group IncI alpha differs from all other plasmids of our Serratia by its capacity of rendering the cells highly resistant to chloramphenicol.

Anti-Bacterial Agents↗
PubMed1985

[Transfer of prophage Mu into methylotrophic bacteria in the plasmid RP4].

Bacteriophage Mu genome has been transferred into the cells of Pseudomonas methanolica and Methylobacterium sp. SKF240, that are naturally resistant to the bacteriophage, as a fragment of a hybrid plasmid RP4::Mu cts62. Temperature induction of the bacteriophage results in host cell lysis. Plasmid RP::Mu cis62 is maintained in methylotrophic cells presenting a cointegrative structure. The genetic and electrophoretic, analyses of the DNA isolated from transconjugant cells have confirmed the conclusion. Bacteriophage Mu propagation has been shown to be restricted in methylotrophic cells.

Bacteriophage mu↗
PubMed1985

[The role of surface structures of recipient cells in bacterial conjugation].

Previously, while studying conjugation process in bacteria, the main attention was given to donors of plasmids. The aim of this review is to show that recipient cells indeed play an important role in this process too. The main attention is given to the structure of recipient cell walls, which is necessary for the recognition of donor cell pili and the establishment of the contact between the cells, i. e. to the first steps of conjugation between gram-negative microorganisms. The evidence concerning the influence of recipient cell walls defects on transmission of some plasmids is presented. The significant role of defects in lipopolysaccharide structure and of the intrinsic features of protein components of the outer membrane is considered. To the author's mind, the diversity in the cell wall structure creates the "outer barriers" for the plasmid exchange between different bacteria. Like the "inner barriers" (restriction, transcription, mistakes, plasmid incompatibility, etc) these "outer barriers" seem to be crucial for genetic isolation of bacterial species. Postulating this process, the author puts forward the idea of applicability of the conception of the biological species to prokaryotes.

Bacteria↗
PubMed1982

[Molecular size of plasmid R18 and its substituted variants in Escherichia coli cells].

R-substituted plasmids (R18Arg) obtained from plasmid R18 and capable to convert Arg- strains E coli to Arg+ strains at the expense of genetic material mobilized from P. aeruginosa chromosome are physically unstable and exist as molecules of different size. It was shown that the physical size of plasmid R18Arg is 3--5 megadaltons greater than those of plasmid R18.

Crosses, Genetic↗