Adenosine 3',5' cyclic monophosphate in Vibrio cholerae

The extracellular concentration of cyclic adenosine 3',5' monophosphate (AMP) of three different strains of V. cholerae growing in syncase medium were measured. Cyclic AMP secreted by V. cholerae 569B varied widely with different carbon sources. Mutant 13, which produced little or no toxin, released half the amount of cyclic AMP as the wild type. The release of less cyclic AMP into the medium by mutant 13 may be accounted for by the lower activity of adenylate cyclase observed. High glucose (3%) in the culture medium reduced the concentration of cyclic AMP both in wild type and mutant 13. Reduction of cyclic AMP levels at high concentrations of glucose (3%) occurred without change of adenylate cyclase activity. The release of enterotoxin to the medium varied with carbon sources but was independent of conditions which reduced the cyclic AMP both within the cell and the medium. Neither adenylate cyclase activity nor toxin production was reduced by an increased concentration of glucose in wild type V. cholerae, whereas cyclic AMP levels were reduced by sixfold. A lower activity of the adenylate cyclase was observed in a mutant of V. cholerae which produced no detectable toxin. Thus, a correlation exists between toxin production and adenylate cyclase activity in V. cholerae.