Biochemistry of Vibrio cholerae virulence. 3. Nutritional requirements for toxin production and the effects of pH on toxin elaboration in chemically defined media.

The investigations described in this report concern the metabolic and physiologic parameters governing cholera enterotoxin production in chemically defined growth media. The results indicate that the minimal nutritional requirements for growth of pathogenic Vibrio cholerae are the same as those for toxin production, and that toxin production parallels growth of the organisms. Studies of the relationship between toxin accumulation and pH reveal that toxin biosynthesis can be separated from toxin release. Toxin is synthesized below pH 7.0, but release and accumulation of extracellular toxin occur only at neutral or alkaline pH values.