Biomedical subjects
Publications and source records attributed to S R Saiamov.
A set of test-strains is suggested; it comprises V. eltor P-13169 and V. cholerae 163-0139 designed for the primary identification of unknown previously choleraic bacteriophages.
Most helocobacteria die as a result of eradication therapy. However, a negligible amount of them revert to the non-cultivated state and remain in the form of coccoids. Based on the literature analysis it has been proved that coccoid forms of H. pylori are viable and their basic properties are similar to those of vegetative helocobacteria forms. It has been suggested for the first time that it is necessary to find therapeutic means for having an impact on helocobacteria, which are in the coccoid form, in addition to standard methods of treatment of helicobacteriosis and its consequences.
Choleric phages were identified in 2 out of 44 samples of Donetsk sewage. Biological properties of phages were characterized.
In the water of open water bodies in the basin of Lake Issyk-Kul the presence of Vibrio cholerae belonging to group O1 and other groups and V. cholerae phages of known serotypes, as well as phages of a new type having no serological and morphological analogs in the current classification of V. cholerae phages, has been established. On the basis of analysis of inaccuracies appearing in the determination of the specificity of V. cholerae phages their systematization within the adequate unified classification of vibriophages is proposed.
Y. pestis L-forms and bacterial forms persist in the body of great gerbils for 40 days. L-forms are poorly phagocytized and can persist in phagocytes for a long time. In guinea pigs immunized with vaccine EV, Y. pestis antigen could be detected till day 160. An unstable L-form was isolated from Ornithodoros mites 3 years after their experimental infection with Y. pestis. Bacterial forms persist in mites for 1-3 years. For 5 years Y. pestis antigen is regularly detected in a high percentage of mites.
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Conditions of cryostabilization of Yersinia pestis phages preserving their biological properties at very low temperature are studied.
Conditions for the appearance of F. tularensis uncultivated forms and for their reversion into the initial state have been studied. As revealed in this study, the combined influence of stress factors (starvation and low temperature) may result in the transition of F. tularensis into the uncultivated state in which it persists in the environment during the period between epidemics. The reversion of F. tularensis uncultivated forms into the initial state has been carried out with the use of sensitive animals. The uncultivated state of F. tularensis should be regarded as the actual form of the existence of the causative agent of tularemia in soil and water ecosystems.
Cholera bacteriophages have been isolated from 27 lysogenic cultures of V. cholerae O139. As shown the pages under study belong to two morphological groups A1 and F1 and serological types II and XII. The use of prophage typing and the sensitivity test to specific phage made it possible to differentiate V. cholerae strains, serogroup O139.
Development of experimental cholera in suckling rabbits is associated with appearance of alterations in glomerular filtration and tubular reabsorption of renal cortex. Ultrastructural changes of nephrons appear in the adhesion period and progress 24 hours later. In this case, particular vulnerability of the kidneys is associated with insufficient development of principal stages both in the cavity and membrane digestion in the gut, therefore, the kidney plays a role of one of the components of the protein-splitting system in the organism.
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.
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Y. pestis cells have been shown capable of binding fibronectin (FN), the presence of adhesion pili considerably enhancing FN binding. The study has established that, along with FN, native adhesive pili, but not subunits, are capable of binding mucin and ganglioside. Structures similar to FN-binding curlings of Escherichia have been found on the surface of Y. pestis cells. The expression of curling-like structures does not depend on the presence of plasmids in Y. pestis cells.
Vibrio albensis phages have been found for the first time. Lysogenic strains of the luminescent vibrios are shown to be producers of moderate phages. The vibrios are attributed to the 1st morphological group according to A. S. Tikhonenko's classification. The studied phages are an independent serological type and have no antigenic affinity to cholera phages.