title: Release of outer membrane fragments from wild-type Escherichia coli and from several E. coli lipopolysaccharide mutants by EDTA and heat shock treatments.
abstract: EDTA-induced outer membrane losses from whole cells of wild-type Escherichia coli (O111:B4) and several lipopolysaccharide (LPS) mutants derived from E. coli K-12 D21 were analyzed. EDTA treatment induced losses of LPS (up to 40%), outer membrane proteins OmpA, OmpF/C, and lipoprotein, periplasmic proteins, and phosphatidylethanolamine. The extent of these releases was strain specific. Successively more EDTA was necessary to induce these losses from strains containing LPS with increasing polysaccharide chain length. An additional heat shock immediately following the EDTA treatment had no effect on LPS release, but it decreased the release of outer membrane proteins and reduced the leakage of periplasmic proteins, suggesting that the temporary increase in outer membrane "permeability" caused by Ca2+-EDTA treatment was rapidly reversed by the redistribution of outer membrane components, a process which is favored by a mild heat shock. The fact that the material released from E. coli C600 showed a constant ratio of lipoprotein, OmpA, and phosphatidylethanolamine at all EDTA concentrations tested suggests that the material is lost as specific outer membrane patches. The envelope alterations caused by EDTA did not result in cell lysis.
authors.affiliation: Department of Biochemistry, University of Groningen, The Netherlands.
authors.forename: H J
authors.initials: HJ
authors.lastname: Marvin
authors.forename: M B
authors.initials: MB
authors.lastname: ter Beest
authors.forename: B
authors.initials: B
authors.lastname: Witholt
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D004492:Edetic Acid / Q000494:pharmacology*; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism / Q000648:ultrastructure; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism; D006358:Hot Temperature; D008070:Lipopolysaccharides / Q000235:genetics / Q000378:metabolism*; D008970:Molecular Weight; D009154:Mutation
chemical_list: D001425:Bacterial Outer Membrane Proteins; D008070:Lipopolysaccharides; D004492:Edetic Acid; D005954:Glucosephosphate Dehydrogenase