[The genome polymorphism of Vibrio cholerae ctxAB(-) strains, containing the proximal part of the CTX element].

The comparative analysis of the hybridization patterns of DNA restricts for 20 V. cholerae, groups 01 and non-01 (non-0139), containing the incomplete CTX element (ctxAB-) was carried out with the use of probes, complementary to the genes of the proximal part of the virulence cassettle and flanking its RS1 sequences. This group was found to be heterogeneous both in the number of copies of "truncated" CTX prophage and their localizations in the genome, as well as in the position of the sites of restriction endonucleases HindlII and BglII.

[Effect of various amino acids and ammonium salts in a synthetic culture media on the cholera enterotoxin production].

The influence of amino acids and ammonium salts on the production of cholera enterotoxin (CT) by 3 Vibrio cholerae strains of different biovars and serogroups was evaluated. As revealed in this study, toxin formation in each of the strains was quantitatively and qualitatively determined by their individual sets of amino acids. The amino acid compositions ensuring the maximum production of CT by the V.

[Analysis of toxin genetic determinants of Vibrio cholerae virulence cassette and neuraminidase with DNA probes].

V. cholerae strains of different origin have been studied for the presence of cholera toxin genes (vct), the proximal part of the virulence cassette including genes zot, ace and orfU, as well as neuraminidase genes (neu), in their genomes with the use of molecular DNA probes. The possibility, in principle, for some strains to lose only a part of their virulence cassette (gene vct), while retaining its proximal part has been shown.

[The evaluation of the virulent properties of Vibrio cholerae O1 by using in-vitro methods].

The virulent properties of V. cholerae O1 (more than 1000 strains) were studied. For this purpose the following methods were used: the determination of hemolytic activity, the express method based on the determination of the speed of mannite oxidation, complex analysis and polymerase chain reaction (PCR).

[Genetic determination and the spectrum of the hemolytic activity of Vibrio cholerae: their significance in the complex of biovar-specific traits].

A collection of 363 V. cholerae strains isolated from different sources were studied by the spectrum of their hemolytic activity in combination with biovar-associated properties. The strains were analyzed for the presence of the cholera toxin (CT) gene (vct) and the hemolysin gene (hly) with the use of the CT probe and a previously cloned 6.

[Species specific DNA probes for identifying Vibrio cholerae].

A 1.74 kb HindIII fragment from a Vibrio cholerae eltor library of genes was found to be strictly specific for Vibrio cholerae strains independent of the biotypes, serotypes and 01-agglutination ability. The fragment was cloned in pUC19 vector plasmid.

[Distribution of lipids and lipolytic activity between the solid and liquid phases of an enteral medium].

Data on the lipid and lipase activity distribution between the solid and liquid phases of the enteric coacervate formed from pancreatic secretion at lower pH is described. It is established that after coacervation the amount of lipids available for extraction increases, the lipase activity of sample grows, the major part of the lipase activity becomes localized in the solid phase. The solid phase is rich in lipids, the content of which pH dependent.

[Role of the enterohepatic circulation of endogenous lipids in food lipid absorption].

In preliminarily operated dogs with fistulas in stomach and different portions of the small intestine, the liver-intestinal circulation of endogenous phospholipids and cholesterine aided to form the chimus all the lipid fractions of which were absorbed proportionally. The recirculation of endogenous lipids seems to be one of the physiological mechanisms of lipid absorption from food in the small intestine.

[Homeostatic influence of the lipid composition of the chyme and the effect of the correlation of basic lipid classes on the intensity of their absorption in the small intestine].

Experiments on normal unanesthetized polyfistulous dogs kept on a mixed diet were made to study the basal lipid ratios of the duodenal and small intestinal chyme. It was shown that the duodenal and small intestinal chyme underwent homeostasis as regards the basal lipid class at the expense of the adding endogenous lipids to digestive juices. The ratios mentioned did not change substantially as a result of lipid absorption during exposure of the chyme in an isolated part of the intestine.