[The toxin-producing capacity of populations of Vibrio cholerae of different origins]. / Toksinprodutsiruiushchaia sposobnost' populiatsii kholernykh vibrionov raznogo proiskhozhdenii.

As the result of the study of toxin formation in 165 V. eltor strains having different virulence, most of the virulent cultures have shown stable toxin production, though 5-10% of their colonies have proved to be nontoxigenic. In faintly virulent strains toxin production was found to be unstable, which is indicative of the heterogeneity of their population composition as regards their capacity for toxin formation. The population of avirulent strains consists mainly of nontoxigenic clones (95.7%).

[Lecithinase activity of Vibrio cholerae and of vibrios not agglutinated by O-cholera serum]. / Letsitinaznaia aktivnost' kholernykh i ne aggliutiniruiushchikhsia O-kholernoi syvorotkoi vibrionov.

The lecithinase activities of 187 V. cholerae strains differing in their virulence and 70 cultures of NAG vibrios of different origin varied in all experimental groups. The level of lecithinase activity in the groups of V. cholerae strains having low virulence, or no virulence at all, was considerably higher than in virulent strains. NAG vibrios isolated from diarrhea patients and from samples of lake and pond water did not differ in the activity of this enzyme.