Ol'ga A Protsenko

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Plasmid content in 242 Yersinia pestis strains from various natural plague foci of the U.S.S.R. and other countries was studied. Of these strains, 172 (71%) were shown to carry three plasmids described previously of about 6, 45-50 and 60 MDa, respectively. Twenty strains (8%) from different foci harboured additional cryptic plasmids, most often of about 20(More)
Yersinia pestis, the causative agent of plague, usually carries three plasmids. The largest of them, a 60 megadalton (MDa) replicon designated pFra determines the synthesis of capsular antigen (fraction I) and murine toxin. Both products are involved in the expression of virulence. Previously, several cases of integration into the bacterial chromosome of(More)
Calcium independent mutants of two Yersinia pestis strains were studied. Insertions of IS100 element at three different sites of plasmid pCad within calcium dependence region were detected in Y. pestis EV, as well as two extensive deletions covering the whole region. It was shown that IS100 carries no HindIII sites. Novel IS element of Y. pestis designated(More)
Yersinia pestis strains with the typical plasmid patterns were shown to have the heterogenic populations. Heterogeneity is increased by cultivation passages in artificial nutrient media and is manifested in plasmid elimination within several clones, plasmid integration into the chromosome, appearance of auxiliary plasmids or the ones with increased(More)
The ability to absorb exogenous pigments (Pgm+) has, until now, been considered an established virulence factor of Yersinia pestis, the causative agent of plague. This property correlates with the sensitivity to the bacteriocin pesticin (Psts). Both functions are chromosomally encoded. In the present study, using Hfr donors and isogenic Pgm-Psts and(More)
Plasmid DNA was isolated from Yersinia pestis strains containing pesticin I or fraction I antigen and "mouse" toxin determinants. Specificity of DNA preparations was studied by using them for transformation of plague agent strains carrying no plasmids. pPstI plasmid (molecular weight 7,0-7,8 MD) encoded pesticin I, fibrinolysin and plasmacoagulase(More)
The genetic analysis of Y. pestis virulence factors accomplished in the 358 strain isogenic system allowed us to determine a minimal set of known factors providing pathogenicity. The combination of chromosomal marker Pgm+ and calcium dependence plasmid (pCad) is shown to be sufficient for preserving the virulence of Y. pestis. Experimental modelling of(More)
The authors present published data and their own findings on the relationship between Yersinia pestis and Y. pseudotuberculosis and on the origination of Y. pestis from Y. pseudotuberculosis. Study of microbiological and biochemical characteristics, external membrane protein spectra, and stability of chromosomal region of pigmentation brought the authors to(More)