[Study of ability to form biofilms in main and non-main subspecies of Yersinia pestis strains].

Aim: To compare biofilm formation in main and non-main subspecies of Yersinia pestis strains as well as in Yersinia pseudotuberculosis strains and to study influence of different genes on expression of this characteristic in different subspecies of Y. pestis.

Materials And Methods: Study of biofilm formation was performed bygrowing cultures on LB broth in polystyrene Petri dishes with subsequent staining of biofilms formed on the dishes' bottom with crystal violet as well as by electron microscopy.

[Molecular mechanisms of the plague pathogenic agent interaction with invertebrates].

Microbe Russian Anti-Plague Research Institute, Saratov, Russia The literature data and experimental results of the authors on the molecular basis of plague agent interaction with invertebrates are discussed. The details of the plague agent life cycle, its genome organization, and molecular genetic mechanisms of its survival in flea vector and on the nematode cuticule are discussed. The experimental data about the ability to form biofilms at abiotic and biotic surfaces in the Yersinia pestis strains of the main and non-main subspecies are presented.

Pleiotropic effects of the lpxM mutation in Yersinia pestis resulting in modification of the biosynthesis of major immunoreactive antigens.

Deletion mutants in the lpxM gene in two Yersinia pestis strains, the live Russian vaccine strain EV NIIEG and a fully virulent strain, 231, synthesise a less toxic penta-acylated lipopolysaccharide (LPS). Analysis of these mutants revealed they possessed marked reductions in expression and immunoreactivity of numerous major proteins and carbohydrate antigens, including F1, Pla, Ymt, V antigen, LPS, and ECA. Moreover, both mutants demonstrated altered epitope specificities of the antigens as determined in immunodot-ELISAs and immunoblotting analyses using a panel of monoclonal antibodies.

[Vibrio cholerae temperate phage O139: characteristics and role in changing expression of chromosomal virulence genes].

Restriction analysis of temperate cholera phage 139 isolated from Vibrio cholerae P16064, serogroup 0139, showed its DNA to be double-stranded linear with cohesive terminals. DNA-DNA hybridization on nylon membranes revealed that many V. cholerae strains of serogroup 0139 isolated in different regions contained a temperate cholera phage 139 in their genomes.