title: Fast lysis of Escherichia coli filament cells requires differentiation of potential division sites.
abstract: Periodic activation of zonal peptidoglycan (murein) synthesis at division sites in Escherichia coli has been reported recently. Zonal synthesis is responsible for septum formation, whereas elongation of the cell sacculus is performed by diffuse insertion of precursors. Zonal synthesis can be triggered in ftsA, ftsQ and ftsI (pbpB) division mutants growing as filaments at the restrictive temperature, but not in ftsZ mutant strains. The lytic response to beta-lactams of cells able or unable to periodically trigger a zonal mode of murein synthesis could be substantially different. Therefore, we investigated the response to the bacteriolytic beta-lactam cefsulodin of ftsZ and ftsI mutants growing at the restrictive (42 degrees C) temperature. The ftsI cells lysed early and quickly after addition of the antibiotic. Sacculi of lysed cells were transversely cut in a very sharp way. In contrast the ftsZ strain lysed late and slowly after addition of the antibiotic and sacculi showed a generalized weakening of the murein network and extended breaks with a frayed appearance. No transversely cut sacculi comparable to those seen in the ftsI samples were found. Our results strongly support that beta-lactam-induced lysis occurs preferentially at division sites because of the activation of zonal murein synthesis at the initiation of septation.
authors.affiliation: Centro de Biología Molecular Severo Ochoa Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Campus de Cantoblanco, 28049 Madrid, Spain. madepedro@cbm.uam.es
authors.forename: Miguel Angel
authors.initials: MA
authors.lastname: de Pedro
authors.forename: Joachim-Volker
authors.initials: JV
authors.lastname: Höltje
authors.forename: Heinz
authors.initials: H
authors.lastname: Schwarz
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics; D001433:Bacteriolysis / Q000187:drug effects*; D002352:Carrier Proteins; D002441:Cefsulodin / Q000494:pharmacology*; D002455:Cell Division / Q000187:drug effects* / Q000502:physiology; D002511:Cephalosporins / Q000494:pharmacology*; D003598:Cytoskeletal Proteins; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics / Q000502:physiology* / Q000648:ultrastructure; D029968:Escherichia coli Proteins; D006602:Hexosyltransferases / Q000235:genetics; D008854:Microscopy, Electron; D009097:Multienzyme Complexes / Q000235:genetics; D002267:Muramoylpentapeptide Carboxypeptidase; D009154:Mutation; D046915:Penicillin-Binding Proteins; D010457:Peptidoglycan / Q000378:metabolism; D046928:Peptidoglycan Glycosyltransferase; D010458:Peptidyl Transferases / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D002511:Cephalosporins; D003598:Cytoskeletal Proteins; D029968:Escherichia coli Proteins; C478704:FtsI protein, E coli; C071525:FtsZ protein, Bacteria; D009097:Multienzyme Complexes; D046915:Penicillin-Binding Proteins; D010457:Peptidoglycan; D010458:Peptidyl Transferases; D006602:Hexosyltransferases; D046928:Peptidoglycan Glycosyltransferase; D002267:Muramoylpentapeptide Carboxypeptidase; D002441:Cefsulodin