CONDITIONS THAT INDUCE STAPHYLOCOCCUS-AUREUS HEAT-SHOCK PROTEINS ALSOINHIBIT AUTOLYSIS

When Staphylococcus nul ens strain 8325 was grown at 30 degrees C and heat shocked at 40 degrees C the rate of cell autolysis in buffer with or without Triton X-100 was reduced. Treatment of growing cells with other agents (CdCl2, ethanol, NaCl) known to induce heal shock protein s also resulted in cells that showed a decreased rate of autolysis. He at shocked cells showed lower rates of freeze-thaw autolysin activity on purified cell walls, and isolated crude cell walls from heat shocke d cells had lower rates of autolytic activity compared to controls. No differences in the peptidoglycan hydrolase activity profiles of contr ol and heat shocked cells were detected by renaturing sodium dodecyl s ulfate polyacrylamide gel electrophoresis. It is proposed that autolys ins are damaged by heat shock and their targeting to the cell wall is impaired, possibly by complexing with heat shock proteins, which may a lso inhibit autolysin activity. Heat shock also inhibited the autolyti c activity of methicillin-resistant and related-susceptible strains, a nd the possible relationship of this to the expression of methicillin resistance is discussed. (C) 1998 Federation of European, Microbiologi cal Societies. Published by Elsevier Science B.V. All rights reserved.