title: Antimicrobial activity of cecropins.
abstract: The lytic peptides, cecropins, were originally isolated from the haemolymph of the giant silk moth, Hyalophora cecropia and possess antibacterial and anticancer activity in vitro. This study investigated the antimicrobial activity of these peptides against human pathogens using standardised assay techniques, and the activity of cecropin B on outer and inner bacterial membranes. From a panel of 15 organisms, Gram-negative bacteria were generally more sensitive to cecropins than Gram-positive organisms, especially the lipopolysaccharide defective mutant, Escherichia coli BUE55. Cecropins B and P1 shared similar MIC values whereas Shiva-1, a cecropin B analogue, was less active. Through combination studies with hydrophobic antibiotics and electron microscopy, cecropin B was shown to disrupt the bacterial outer membrane. Protoplasts of Staphylococcus aureus and Staphylococcus epidermidis were resistant to cecropin B, suggesting that the cytoplasmic membranes of Gram-positive organisms were inherently more resistant to the peptide.
authors.affiliation: Department of Biomedical Sciences, University of Bradford, West Yorkshire, UK.
authors.forename: A J
authors.initials: AJ
authors.lastname: Moore
authors.forename: W D
authors.initials: WD
authors.lastname: Beazley
authors.forename: M C
authors.initials: MC
authors.lastname: Bibby
authors.forename: D A
authors.initials: DA
authors.lastname: Devine
mesh_terms: D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D023181:Antimicrobial Cationic Peptides; D002462:Cell Membrane / Q000187:drug effects / Q000648:ultrastructure; D002463:Cell Membrane Permeability / Q000187:drug effects; D004353:Drug Evaluation, Preclinical; D004357:Drug Synergism; D004912:Erythrocytes / Q000187:drug effects; D006090:Gram-Negative Bacteria / Q000187:drug effects* / Q000648:ultrastructure; D006094:Gram-Positive Bacteria / Q000187:drug effects* / Q000648:ultrastructure; D006801:Humans; D007301:Insect Hormones / Q000494:pharmacology*; D019476:Insect Proteins; D008826:Microbial Sensitivity Tests / Q000379:methods; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D010455:Peptides / Q000494:pharmacology*; D011523:Protoplasts / Q000187:drug effects; D013104:Spheroplasts / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D023181:Antimicrobial Cationic Peptides; D007301:Insect Hormones; D019476:Insect Proteins; D010455:Peptides; C057355:Shiva-1; C031162:cecropin B protein, Insecta; C070016:cecropin P1-LI