title: Mode of action of antimicrobial peptide P45 on Listeria monocytogenes.
abstract: The mode of action of an antimicrobial peptide produced by Bacillus sp. P45 isolated from the intestine of the Amazonian basin fish Piaractus mesopotamicus was investigated. The antimicrobial peptide was purified from culture supernatants by precipitation with ammonium sulfate and gel filtration chromatography. The peptide has an EC(50) of 300 AU (activity units) ml(-1) and kills all viable cells of Listeria monocytogenes with a concentration of 800 AU ml(-1). A decrease in OD was observed when L. monocytogenes cultures were treated with the peptide, suggesting that cells were lysed. Transmission electron microscopy showed damage of the cell envelope and loss of protoplasmic material. The peptide P45 was bactericidal and bacteriolytic to L. monocytogenes. There is evidence that the mode of action is interfering at cell membranes and the cell wall. The knowledge of the mode of action of antimicrobial peptides is an essential step to consider their utilization in food or clinic.
authors.affiliation: Laboratório de Bioquímica e Microbiologia Aplicada, Instituto de Ciência e Tecnologia de Alimentos, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: Lisana Reginini
authors.initials: LR
authors.lastname: Sirtori
authors.forename: Amanda de Souza da
authors.initials: Ade S
authors.lastname: Motta
authors.forename: Adriano
authors.initials: A
authors.lastname: Brandelli
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D023181:Antimicrobial Cationic Peptides / Q000494:pharmacology*; D001407:Bacillus / Q000378:metabolism*; D002462:Cell Membrane / Q000187:drug effects / Q000648:ultrastructure; D002473:Cell Wall / Q000187:drug effects / Q000648:ultrastructure; D005399:Fishes / Q000235:genetics*; D008089:Listeria monocytogenes / Q000187:drug effects* / Q000648:ultrastructure; D008826:Microbial Sensitivity Tests; D046529:Microscopy, Electron, Transmission
chemical_list: D000900:Anti-Bacterial Agents; D023181:Antimicrobial Cationic Peptides