Aflatoxin B1 effect on enzyme biosynthesis in Bacillus cereus and Bacillus licheniformis

Abstract

The effect of aflatoxin B1 on induced and constitutive enzyme synthesis was examined in strains of Bacillus cereus (NRRL B-569, NRRL B-3537) and Bacillus licheniformis (NRRL B-3560, NRRL B-3540). Although B1 partially blocked penicillinase elaboration in B. cereus after incubation with the toxin, the level of B1-mediated reduction in total protein synthesis was similar to the diminished production of penicillinase. Comparative studies on the effects of aflatoxin B1 and actinomycin D on enzyme synthesis and growth in B. licheniformis demonstrated that actinomycin D exerted a differential inhibitory effect on induction of penicillinase and α-glucosidase, whereas levels of reduction of enzyme production initiated by aflatoxin resembled toxin-mediated growth inhibition. Thus, the mode of action of aflatoxin B1 is not exclusively analogous to that of actinomycin D in B. licheniformis. However, induced-penicillinase production in B. licheniformis was enhanced by relatively low levels of both actinomycin D and aflatoxin B1.