Apparent Obligatory Dependence of Peptidoglycan Synthesis on Phospholipid Synthesis Studied in Ether-Treated Escherichia coli
Amino acid deprivation of Escherichia coli activates ppGpp synthetase I, a ribosome-associated enzyme encoded by the relA gene (reviewed by Cashel and Rudd, 1987). This results in the rapid accumulation of guanosine 5′-diphosphate 3′-diphosphate (ppGpp) in relA + bacteria but not in relA mutants; ppGpp is a putative stress signal compound specifying amino acid deficiency which apparently shuts down a variety of energy-consuming metabolic processes in starved bacteria in what has been termed the stringent response (Cashel and Rudd, 1987). The activities of both the peptidoglycan biosynthetic and the hydrolase systems are among the metabolic processes which are inhibited during the stringent response, and this may account for the well known penicillin tolerance exhibited by amino acid-deprived relA + bacteria (Pisabarro et al., 1991). The fact that amino-acid deprived relA mutant strains lyse when treated with penicillin is consistent with this proposal. Furthermore, lysis of amino acid-deprived relA + cells by inhibitors of peptidoglycan synthesis can be induced by the addition of agents, such as chloramphenicol, which interfere with the stringent response. These stringent response antagonists block the synthesis of ppGpp during amino acid deprivation (Cashel and Rudd, 1987).
KeywordsStringent Response Phospholipid Synthesis Peptidoglycan Synthesis Amino Acid Deprivation Amino Acid Deficiency
Unable to display preview. Download preview PDF.
- Cashel, M. and Rudd, K.E. (1987) The stringent response, in “Escherichia coli and Salmonella typhimurium. Cellular and Molecular Biology” (F.C. Neidhardt, J.L. Ingraham, K.B. Low, B. Magasanik, J. Schaecter, and H.E. Umbarger, Ed.), pp. 1410–1438. American Society for Microbiology, Washington, D.C.Google Scholar
- Harkness, R.E., Mirelman, D. and Ishiguro, E.E. (1983) Regulation of D-alanine carboxypeptidase and peptidoglycan cross-linkage in amino acid-deprived Escherichia coli. J. Bacteriol. 145, 845–849.Google Scholar
- Ishiguro, E.E. (1983) Mechanism of stringent control of peptidoglycan synthesis in Escherichia coli, in “The Target of Penicillin” (R. Hakenbeck, J.-V. Höltje and H. Labischinski, Ed.), pp. 631–636, Walter de Gruyter & Co., Berlin.Google Scholar