[Experimental non-culturable Vibrio cholerae eltor and its biological properties]. / Eksperimental'noe poluchenie nekul'tiviruemykh form Vibrio cholerae eltor i kharakteristika ikh biologicheskikh svoistv.

In experiments with the cultivation of V. cholerae eltor under the conditions of high salt concentration, as well as low temperature and deficiency in nutrient substances, uncultivable forms (UF) of toxigenic and nontoxigenic vibrios were obtained. The absence of growth of seeded vibrios after the filtration of samples (with a filter of 0.22 micron), the preservation of specific antigenic determinants and the initial set of genes, changes in the morphology of cells (small size, coccoid form with the flagella retained) confirm the transition of V. cholerae eltor under study into the uncultivable state which, under unfavorable conditions, more rapidly develops in toxigenic vibrios than in nontoxigenic ones. The analysis of the INT-reductase activity of UF disintegrates revealed that they had endogenic respiration whose activity increased (4.5- to 6.5-fold) in the presence of the exogenic intermediates of the Krebs cycle. The uncultivable forms of the vibrios retain genes responsible for pathogenicity, as well as their antigenic determinants.

[Analysis of PCR-diagnosis of brucellosis in human]. / Osobennosti PTsR-diagnostiki brutselleznoi infektsii u liudei.

Polymerase chain reaction (PCR) was used for the diagnosis of brucellosis in humans with different forms of this disease. A high incidence (77.6%) of Brucella infection was revealed in the staff of cattle breeding centers with unfavorable situation with regard to brucellosis. Such a conclusion was made after PCR testing of native human sera. In acute brucellosis of humans amplification of the specific site of brucella DNA in PCR is possible only after extraction of DNA by a procedure adapted for DNA extraction from intact brucella cells. In chronic infection weak amplification of brucella genome DNA fragment was observed in investigation of native sera by the PCR. More expressed amplification product was recorded in PCR with a DNA precipitate from this serum obtained by ethanol precipitation. A still higher level of brucella DNA fragment amplification was observed after DNA extraction from sediment obtained by ethanol precipitation from this serum. These data confirmed the incomplete phagocytosis phenomenon at the early stage of infection, known in brucellosis pathogenesis, and allowed some hypotheses on the pathogenesis of chronic phase of brucellosis infection.

[The circulation of the California encephalitis complex and Batai viruses in the Lake Baikal region (serological research data)]. / O tsirkuliatsii virusov kompleksa kaliforniiskogo éntsefalita i Batai v Pribaikal'e (dannye serologicheskikh issledovanii).

The serological materials of the indigenous population and cattle suggest that there are viral foci of a complex of California encephalitis with the circulation of viruses of Inkoo, Tahyna [correction of Tyagin], and the white hare. The results of examining the residents of Irkutsk also suggest that there are urban viral foci of a complex of California encephalitis. The epidemiological potential of the natural foci of Batai virus is insignificant in the Baikal region.

[The interrelationships between Vibrio cholerae and the infusorian Tetrahymena pyriformis]. / Izuchenie vzaimootnoshenii Vibrio cholerae s infuzoriiami Tetrahymena pyriformis.

The results of the study of interaction between V. cholerae of different virulence and T. pyriformis are presented. The study has revealed the heterogeneity of V. cholerae population: alongside easily phagocytized vibrios, there are vibrios resistant to the digestive action of T. pyriformis. An increase in the number of V. cholerae in association with T. pyriformis has been evaluated, taking into account the selective multiplication of vibrios resistant to phagocytosis. The data on changes in the agglutinative, phagolytic and virulent properties of V. cholerae cultivated together with T. pyriformis are presented. The suggestion has been made that protozoa can function as hosts of pathogenic vibrios supporting their existence in water.

[The variability of Yersinia pestis in the body of the flea]. / Izmenchivost' Yersinia pestis v organizme blokhi.

Changes in the morphology and ultrastructure of Y.pestis cells at different periods of their stay in the body of fleas (Citellophilus tesquorum altaicus) have been studied. The study, carried out by means of optical and electron microscopy, as well as with the use of a culture medium for the isolation of L-forms, has revealed that in the body of fleas Y.pestis cells undergo the effect of processes leading to their L-transformation. As the result of L-transformation, the infective agent may take altered forms, including L-like variants. Such forms are retained in hungry insects and are capable of prolonged survival in the body of the carrier.

[The isolation of the morbilli virus from the Baikal seal Phoca sibirica and its preliminary characterization]. / Vydelenie morbillivirusa ot baikal'skoi nerpy Phoca sibirica i ego predvaritel'naia kharakteristika.

A morbillivirus was isolated from the organs of a seal (Phoca sibirica) which had died during 1987-1988 epizootic in Baikal. This Baikal seal morbillivirus (BSM) was adapted to Vero cell cultures in which it induced a cytopathic effect developing to complete destruction of the monolayer. Typing of BSM was done by indirect immunofluorescence test and enzyme immunoassay using antibodies to distemper and measles viruses. A method for virus concentration and purification was developed. According to electron microscopic examinations, the virus virions were spherical particles of heterogeneous sizes over 100 nm in diameter. The clinical picture of seal infection, pathological anatomy and histopathology are described. A possible role of BSM in the epizootics of Baikal seals is discussed.