title: Phylloseptin-1 (PSN-1) from Phyllomedusa sauvagei skin secretion: a novel broad-spectrum antimicrobial peptide with antibiofilm activity.
abstract: Amphibian skin secretions have proven to be rich sources of antimicrobial peptides that are proposed to be fundamental components of the innate immune system. As amphibian skin is a multi-functional organ playing, among other things, a crucial role in respiration, it has been deemed that a core biological role for such peptides is control of microbial flora on this surface. To date, however, antimicrobial efficacy has been universally determined by means of establishing minimum inhibitory concentrations (MICs) using planktonic organisms rather than those within a biofilm such as would occur on this exposed surface. Here we describe the identification and structural characterisation of a novel 19 amino acid residue antimicrobial peptide of the phylloseptin family, named PSN-1, from the skin secretion of the waxy monkey frog, Phyllomedusa sauvagei. PSN-1 displayed broad-spectrum activity against a range of planktonic organisms with a high potency (MIC 5 microM) against Staphylococcus aureus. In a specific bioassay with the same organism grown as a biofilm, the minimal biofilm eradication concentration (MBEC) was found to be of the same high potency (5 microM). The present data would suggest that evaluation of actions and potency of amphibian skin secretion antimicrobial peptides might best be achieved by evaluating MBEC rather than MIC using planktonic organisms and that data arising from such studies may have more biological relevance in reflecting the purpose for which they have evolved through natural selection.
authors.affiliation: Molecular Therapeutics Research, School of Pharmacy, Medical Biology Centre, Queen's University, Belfast BT9 7BL, Northern Ireland, UK.
authors.forename: Ruowen
authors.initials: R
authors.lastname: Zhang
authors.forename: Mei
authors.initials: M
authors.lastname: Zhou
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.forename: Stef
authors.initials: S
authors.lastname: McGrath
authors.forename: Tianbao
authors.initials: T
authors.lastname: Chen
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Chen
authors.forename: Chris
authors.initials: C
authors.lastname: Shaw
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry / Q000235:genetics / Q000494:pharmacology*; D001483:Base Sequence; D018441:Biofilms / Q000187:drug effects*; D003001:Cloning, Molecular; D006461:Hemolysis; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D011898:Ranidae; D013211:Staphylococcus aureus / Q000187:drug effects
chemical_list: D023181:Antimicrobial Cationic Peptides; C533251:phylloseptin-1, Phyllomedusa