EFFECT OF PLANT ALKALOIDS ON THE SPORULATION OF A FOOD-BORNE PATHOGEN
In the presence of 100 μg of caffeine per ml or 200 μg of theobromine per ml, sporulation of Clostridium perfringens NCTC 8679 rose from less than 1 to 80 or 85%. Enterotoxin concentration increased from undetectable levels to 450 μg/mg of cell extract protein. Heat-resistant spore levels increased from less than 1000 to between 1 x 107 and 2 x 107/ml. These effects were partially reversible by the addition of adenosine or thymidine. In the case of NCTC 8238, caffeine and theobromine caused a three- to fourfold increase in the percentages of cells possessing retractile spores and a similar increase in enterotoxin concentration. Heat-resistant spore levels, however, were unaffected. Inosine was ineffective in promoting sporulation in NCTC 8679. The mechanism by which caffeine stimulates sporulation of Clostridium perfringens was investigated. Results indicated that cultures exposed to caffeine had significantly elevated levels of intracellular adenosine and guanosine triphosphates.