Relation between cell wall turnover and cell growth in Bacillus subtilis

Abstract

The kinetics of cell wall turnover in B. subtilis were examined in detail. After pulse labeling of the peptidoglycan with N-acetylglucosamine, the newly formed peptidoglycan is stable for .apprx. 3/4 of a generation and is then degraded by a process that follows 1st-order kinetics. Deprivation of an auxotroph of amino acids required for proetin synthesis results in a turnover cessation. If a period of amino acid starvation occurs during the lag phase of turnover, then the turnover initiation is delayed for a period of time equivalent to the starvation period. During amino acid starvation, new cell wall peptidoglycan is synthesized and added to preexisting cell wall. This peptidoglycan after resumption of growth is also subject to degradation (turnover). Cell wall turnover is probably dependent on cell growth and elongation. Several possible control mechanisms for cell wall autolytic enzymes are discused in light of these observations.