PHYSIOLOGY OF TOXIN PRODUCTION BY CLOSTRIDIUM BOTULINUM TYPES A AND B IV

Abstract

]The potential toxicity of cultures of C. botulinum in the exponential growth phase was found to be much greater than their apparent toxicity. This was demonstrated by sonic disintegration of the cells followed by treatment of the extract with trypsin. The increase in toxicity noted during the period of active autolysis could not be attributed to protein synthesis de novo since this increased was noted in the presence of chloramphenicol, an effective inhibitor of protein synthesis. In addition, no increase in total protein could be demonstrated during the autolytic period. It was concluded the toxins of types A and B are initially synthesized as large molecules with comparatively low biological activity owing to masking of active chemical groupings. These toxin "precursors" must be partially degraded, probably by the proteolytic enzyme of the organisms, before manifesting their full toxic potentialities.