[Effect of plague "murine" toxin on activity of antioxidant system in cells of experimental animals].

AIM: To study nature of changes in components of glutathione disulfide system of experimental animals influenced by plague "murine" toxin. MATERIALS AND METHODS: Total glutathione level as well as levels of oxidated (G-SS-G) and reduced (GSH) forms of glutathione, activity of glutathione reductase and glutathione peroxidase in erythrocytes of Mongolian gerbils (Meriones unguiculatus), mice and guinea pigs were studied. RESULTS: Sharp decrease of reduced glutathione level as well as increase of oxidated glutathione level were observed in all experimental animal species after intraperitoneal administration of plague "murine" toxin. Changes in levels of GSH and G-SS-G were followed with decrease of total glutathione level. Activity of glutathione peroxidase was decreased in mice and Mongolian gerbils. There was increase of activity of this enzyme in guinea pigs. Level of glutathione reductase was decreased in all studied animals. CONCLUSION: Performed studies allow to hypothesize that oxidation of thiolic functional groups in organisms of animals as a result of H2O2 generation has important role during plague intoxication (administration of sublethal doses of plague "murine" toxin).

[Morphology and enzyme activity of nonculturable forms of Vibrio cholerae]. / Morfologiia i fermentativnaia aktivnost' nekul'tiviruemykh form cholernykh vibrionov.

The transition of V. cholerae into the uncultivable state under experimental conditions was accompanied by gradual changes in their morphology, motility and metabolic activity. The vibrios took the oval form, lost their flagellum, motility and enzyme activity on diagnostic media. Dehydrogenase activity tested by reduction of triphenyl tetrazolium chloride, increased at the initial stages and dropped to the initial level or even lower by the end of the observation period (10 months). Similar dynamics was noted when the cytoplasmatic marker enzyme--ATPase activity was studied. Glucose catabolism in the uncultivable forms shifted towards glycolysis. During 1-2 months ctx and tcp genes could be detected in these forms by the PCR. The dynamics of the biological properties under study made it possible to find out the existence of 3 functionally different stages in the development of an uncultivable population.

[Evaluation of hypoxic state in experimental animals induced by Yersinia pestis antigens]. / Otsenka gipoksicheskogo sostoianiia u éksperimental'nykh zhivotnykh pod vliianiem antigenov Yersiniia pestis.

Some characteristics of purine metabolism in experimental animals (white mice, clawed jirds and guinea pigs), injected intraperitoneally with Y. pestis "murine" toxin and capsular antigen (Fraction 1), were studied. Under the influence of sublethal doses of these antigens increased levels of guanine and xanthine in blood were noted. Changes in the content of xanthine oxidase in cells were insignificant. In white mice and clawed jirds the activity of succinate dehydrogenase decreased under the action of "murine" toxin and increased after the injection of Fraction 1.

[Characteristics of the acid-alkali equilibrium in blood of experimental animals in response to exposure of 'murine' toxin and Yersinia pestis capsular antigen]. / Pokazateli kislotno-shchelochnogo ravnovesiia krovi u éksperimental'nykh zhivotnykh pod vliianiem "myshinogo" toksina i kapsul'nogo antigena Yersinia pestis.

As revealed in this study, metabolic acidosis is observed in experimental animals the influence of "murine" toxin and Y. pestis fraction I, which is manifested by the parameters of the acid-base state, the gas composition of blood and the content of electrolytes.

[The characteristics of the action of the capsular antigen of Yersinia pestis on cells from plague-susceptible and -insusceptible rodents]. / Nekotorye osobennosti deistviia kapsul'nogo antigena Yersinia pestis na kletki chuvstvitel'nykh i ne chuvstvitel'nykh k chume gryzunov.

The state of the functional activity of peritoneal leukocytes from different species of gerbils (Mongolian gerbils, Libyan jirds, as well as gerbils inhabiting the right and left banks of the Volga), exposed to the action of Y. pestis capsular antigen, has been found to correlate with the susceptibility of these animals to plague.

[The tissue heterogeneity of mononuclear phagocyte system cells interacting with Yersinia pestis]. / Tkanevaia geterogennost' kletok sistemy mononuklearnykh fagotsitov pri vzaimodeistvii s Yersinia pestis.

The work deals with the determination of the heterogeneity of cells of the mononuclear phagocyte system, localized in different tissues, in their interaction with Y. pestis. The macrophage populations under study have been found to be heterogeneous in their phagocytic activity with respect to Y. pestis. The digestive activity of alveolar macrophages is considerably lower than that of macrophages localized in other tissues. Macrophages obtained from different tissue are heterogeneous also in the intensity of changes in oxygen-dependent metabolic processes during their contacts with Y. pestis. Alveolar macrophages are less active in this respect than peritoneal ones. Alveolar macrophages under study have been shown to have their own characteristic features; for this reason, the data obtained in the study of one of these populations should not be extrapolated to other populations.

[Iron assimilation by Yersinia pestis on iron-deficient media]. / Izuchenie assimiliatsii chumnym mikrobom zheleza v usloviiakh zhelezodefitsitnykh sred.

The growth of plague bacteria may be limited by the level of iron concentration in the nutrient medium. The virulent strains of the plague microbe possess the more pronounced mechanism of iron assimilation as compared to the vaccine strain. The iron ions are extracted by the virulent and vaccine strains only under the cell surface contact with the iron-saturated transferrin. The iron-sorbing function is peculiar to the plague microbe cell walls which is pronounced more strongly in the virulent strains.