title: Atomic force microscopy study of the effect of antimicrobial peptides on the cell envelope of Escherichia coli.
abstract: The influences of the antibacterial magainin 2 and PGLa from the African clawed frog (Xenopus laevis) and the hemolytic bee venom melittin on Escherichia coli as the target cell were studied by atomic force microscopy (AFM). Nanometer-scale images of the effects of the peptides on this gram-negative bacterium's cell envelope were obtained in situ without the use of fixing agents. These high-resolution AFM images of the surviving and intact target cells before and after peptide treatment showed distinct changes in cell envelope morphology as a consequence of peptide action. Although all three peptides are lytic to E. coli, it is clear from this AFM study that each peptide causes distinct morphological changes in the outer membrane and in some cases the inner membrane, probably as a consequence of different mechanisms of action.
authors.affiliation: UNESCO Associated Centre for Macromolecules, Department of Chemistry, University of Stellenbosch, Matieland, South Africa.
authors.forename: M
authors.initials: M
authors.lastname: Meincken
authors.forename: D L
authors.initials: DL
authors.lastname: Holroyd
authors.forename: M
authors.initials: M
authors.lastname: Rautenbach
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D023181:Antimicrobial Cationic Peptides / Q000494:pharmacology*; D004926:Escherichia coli / Q000166:cytology / Q000187:drug effects* / Q000235:genetics; D054806:Magainins; D008555:Melitten / Q000494:pharmacology*; D018625:Microscopy, Atomic Force; D029867:Xenopus Proteins / Q000494:pharmacology*; D014982:Xenopus laevis
chemical_list: D000900:Anti-Bacterial Agents; D023181:Antimicrobial Cationic Peptides; D054806:Magainins; D029867:Xenopus Proteins; C045866:peptide-Gly-Leu-amide; C053301:magainin 2 peptide, Xenopus; D008555:Melitten