Cell wall turnover in growing and nongrowing cultures of Bacillus subtilis

Abstract

Cell wall turnover was studied in cultures of Bacillus subtilis in which growth was inhibited by nutrient starvation or by the addition of antibiotics. Concomitantly, the synthesis of wall, as measured by the incorporation of radioactively labeled N-acetylglucosamine, was followed in some of these cultures. In potassium- or phosphate-starved cultures, growth stopped, but wall turnover continued at a rate slightly lower than that in the control cultures. Lysis of cells did not occur. In glucose-starved cultures, continued wall turnover caused lysis of cells, since wall synthesis apparently was inhibited. The same phenomenon was observed after growth arrest by the addition of wall synthesis inhibitors such as fosfomycin, cycloserine, penicillin G, and vancomycin. Growth arrest by the addition of chloramphenicol allowed the continuation of wall synthesis; therefore, the observed turnover generally did not cause cell lysis.

The essential YycFG two‐component system controls cell wall metabolism in Bacillus subtilis

“…7B. In wild‐type strain 168 (circles) there was an 80% decrease in cell‐associated radioactivity during the experiment that occurred with a characteristic sigmoidal kinetic profile, previously observed by de Boer et al . (1982).…”

Bacterial peptidoglycan (murein) hydrolases

“…Cell wall turnover has been studied extensively in B. subtilis (Hughes et al , 1970; Pooley, 1976). Importantly, there is a correlation between the growth rate and the rate of cell wall turnover (de Boer et al , 1981, 1982; Cheung et al , 1983), indicating that the hydrolases are more active at high growth rates. Because of the requirement to cleave covalent bonds to allow cell wall enlargement, it has been speculated that hydrolases are pacemakers for cell growth (Höltje, 1995).…”

The death and lysis of microorganisms in environmental processes

“…The class of enzymes responsible for cell wall polymer hydrolysis have been termed autolysins and their action can be broadly divided into (a) constructive or voluntary and (b) destructive or involuntary. Constructive properties are exhibited while the control mechanisms of the autolysins are still effective and include daughter cell separation [150,151], turnover and expansion of cell wall biopolymers [152][153][154][155][156], and morphological differentiation [151,157]. Should this tight control of autolysin activity break down, then the destructive roles of the autolysins are manifested by the rupture of cell walls, leading to loss of cell activity and eventually to total dissolution of cellular integrity.…”