Secretion of lipids induced by inhibition of peptidoglycan synthesis in streptococci

Abstract

Inhibition of peptidoglycan synthesis causes an immediate and massive secretion of newly synthesized and old lipids from several species of bacteria, including streptococci, Staphylococcus epidermidis and Bacillus subtilis. Lipid secretion occurs in the absence of detectable bacterial lysis. This novel phenomenon was examined in more detail in 3 strains of streptococci: S. sanguis (group H), S. pyogenes (group A) and S. pneumoniae. The secretion of lipids is specifically induced by inhibitors of peptidoglycan synthesis; it is not caused by inhibitors of protein, RNA or DNA synthesis. The occurrence appears to be reversible since penicillin-induced secretion comes to a halt upon the timely addition of penicillinase, correlating with resumption of culture growth. All cellular lipids are secreted in essentially the same proportions as those found in the drug-treated bacteria. Continued peptidoglycan synthesis may be essential for the integration and retention of lipid material in the plasma membrane.