Saratov, Russia
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Smirnova N.I.,Universitetskaya Street | Agafonov D.A.,Universitetskaya Street | Kul'shan' T.A.,Universitetskaya Street | Krasnov Ya.M.,Universitetskaya Street | Kutyrev V.V.,Universitetskaya Street
Vestnik Rossiiskoi Akademii Meditsinskikh Nauk | Year: 2014

Aim: To carry out comparative molecular genetic analysis of highly pathogenic atypical Vibrio cholerae strains biovar El Tor, isolated in the territory of RF, in order to determine micro-evolutionary alterations of cholera agent in the modern period. Materials and methods: 38 clinical strains have been examined by means of polymerase chain reaction, sequencing and MLVA-analysis. The selected strains were isolated at different periods of time during cholera epidemic complications and differed between each other in virulence. Results: It is demonstrated that new variants have emerged in the course of short-term microevolution. Their genome structure and function differ from those of all previously known strains. The genome alterations have been caused by point mutations in ctxB u tcpA genes associated with virulence and located in CTXφ prophage and pathogenicity island VPI-1 respectively, as well as by the extended deletion in pandemicity island VSP-II. Presented is the dynamics of genome structure and function alterations in modern strains. Conclusion: The discovered genomic alterations in the new variants of the agent evolved in the process of microevolution are indicative of their epidemic potential enhancement and probability of virulence potentiation. © 2014, Izdatel'stvo Meditsina. All rights reserved.

Eroshenko G.A.,Universitetskaya Street | Kutyrev V.V.,Universitetskaya Street
Advances in Experimental Medicine and Biology | Year: 2012

We have completed a comparative analysis of the biochemical and genetic characteristics of Yersinia pestis strains belonging to the main (highly virulent) and non-main (selective virulence) subspecies (ssp.) to elucidate the phylogenetic relationship of the non-main ssp. in the general scheme of the plague agent evolution. It has been established that several metabolic genes such as napA (nitrate reduction), rhaS (rhamnose fermentation), melB (melibiose fermentation), and iclR (isocytrate lyase production) have undergone reductive evolution in the Y. pestis main ssp. strains but remain intact in the strains of the non-main ssp. Sequencing of the genes encoding the differential biochemical properties used for intraspecific classification of the plague agent as well as other housekeeping genes showed that the non-main ssp. strains are the most evolutionarily ancient forms of Y. pestis. Of the non-main ssp., the caucasica ssp. strains are the most ancient, lacking the plasmid of pesticinogenicity pPst and containing the genes encoding wild-type differential biochemical characteristics, similar to the Yersinia pseudotuberculosis strains. © 2012 Springer Science+Business Media New York.

Konnov N.P.,Universitetskaya Street | Popov N.V.,Universitetskaya Street | Velichko L.N.,Universitetskaya Street | Knyazeva T.V.,Universitetskaya Street
Entomological Review | Year: 2010

The paper considers, for the first time, the formation of the extracellular matrix envelope (EME), or the biofilm, by Yersinia pestis as the basis determining the nature of interaction of the plague agent with the flea organism. The significance of the insect proventriculus in the process of biofilm formation is shown. The ultrastructure of the conglomerates of the plague microbe in the flea proventriculus and midgut was studied and the uniform mechanism of their formation was established. The role of Yersinia pestis biofilm in preservation of the plague microbe in the intestine of ectoparasites and in the soil of rodent burrows was discussed. PCR analysis confirmed the presence of the agent in plague infected corpses and flea feces stored at +8-10°C for 7 years and 9 months. © 2010 Pleiades Publishing, Ltd.

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