Inhibition of Secretion of Staphylococcal Alph Toxin by Cerulenin

Abstract

Secretion of .alpha. toxin by Staphylococcus aureus strain Wood 46 was preferentially inhibited by cerulenin, an antibiotic that stops fatty-acid synthesis by inhibiting .beta.-keto acyl acyl carrier-protein synthetase. At the concentrations used, cerulenin had a negligible effect on cell growth and total protein synthesis, but reduced lipid synthesis by 50%. Extracellular and membrane-associated .alpha. toxin was absent in cultures treated with cerulenin, but toxin formation was resumed after either removal of the antibiotic or addition of exogenous fatty acids. The apparent absence of toxin precursor in membranes of inhibited cells favors inhibition at an earlier stage in toxin synthesis.