Biosynthesis of peptidoglycan in Pseudomonas aeruginosa. 2. Mode of action of beta-lactam antibiotics.
The intrinsic effect of various beta-lactam antibiotics on the biosynthesis of peptidoglycan of Pseudomonas aeruginosa X-48 was investigated. Most of the cephalosporins and penicillins tested already at 0.5 microgram/ml strongly inhibited (a) the incorporation of nascent peptidoglycan into the detergent-insoluble fraction (greater than 75%), (b) the formation of peptide crosslinkages (greater than 60%) and (c) the activity of the DD-carboxypeptidase and partially that of the transpeptidase (approximately 90% and approximately 40% respectively). Another group of beta-lactum drugs did not inhibit incorporation into the material insoluble in sodium dodecylsulfate, the formation of peptide crosslinkages nor transpeptidase activity. They only partially inhibited the activity of the DD-carboxypeptidase--endopeptidase system (40--50% at 0.5 microgram/ml). The results obtained differ from those of Presslitz and Ray [Antimicrob, Agents Chemother. 7, 578--581 (1975)] and show some resemblance to the effects of beta-lactams on the biosynthesis of Escherichia coli peptidoglycan.
D000117:Acetylglucosamine / Q000378:metabolism; D002511:Cephalosporins / Q000494:pharmacology*; D046911:Macromolecular Substances; D010406:Penicillins / Q000494:pharmacology*; D010457:Peptidoglycan / Q000096:biosynthesis*; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000378:metabolism*; D013329:Structure-Activity Relationship
D002511:Cephalosporins; D046911:Macromolecular Substances; D010406:Penicillins; D010457:Peptidoglycan; D000117:Acetylglucosamine