Induction of autolysis in Bacillus subtilis by ochratoxin A.

Ochratoxin A (OTA) added during the exponential growth phase at a concentration higher than 12 microgram/ml caused autolysis of Bacillus subtilis. Optical density of cultures decreased, and at higher concentrations the cultures became sterile. Optimum OTA-induced lysis was about pH 5. At concentrations below 10 microgram/ml, protein synthesis was inhibited more strongly than RNA synthesis. Cell wall synthesis was also strongly inhibited. A fraction extracted from the lysates had the property of a lysis inhibitor. The relevance of this fraction in respect to autolysis is discussed.