[Method of extracting cholera toxin from solid media containing cultured vibrios].

The possibility of obtaining biologically active cholerogen by extracting it from solid culture media used for the cultivation of vibrios is shown. V. cholerae, strain 569B, cultivated on solid media produced about 3 times more toxin per 1 ml of the culture medium than during the process of its cultivation with the use of liquid culture media.

[Role of adrenal cortex hormones in the realization of the biological action of cholerogen].

Experiments were conducted on albino mice, guinea pigs, and rabbits. The role played by glucocorticoids in the realization of the biological action of cholerogen--cholera exotoxin (edema of the limbs in mice and the skin test after Craig in guinea pigs and rabbits) was studied. Tissue sensitivity of these animals to the action of cholerogen diminished under the effect of stress factors (intramuscular injection of formalin, intraperitoneal injection of cholerogen, immobilization, hunger, laparatomy, etc.

[Choleragen and neuraminidase production by Vibrio in vitro].

In vitro studies demonstrated a high degree of the rank correlation between the synthesis of cholera exotoxin and neuraminidase by cholera vibrios (V. cholerae 569B). The appearance of these biochemically-active materials proved to depend on the growth phase of the microbial population.

[Reduction of the biological activity of Vibrio cholerae culture filtrates exposed to neuraminidase inhibitors].

Experiments were conducted on a model of edema of albino mouse paws; a study was made of the effect of neuraminidase inhibitors on the cholerogenic effect of a filtrate of cholera vibrio culture. It appeared that addition to the filtrate of inhibitors depressed its biological activity. Since no cholerogenic action was possessed by the purified neuraminidase preparations from the cholera vibrios it was suggested that there existed a chemical affinity between the region of cholerogen responsible for fixation on the cell membranes and the active neuraminidase centre.