title: Skin peptides of different life stages of Ewing's tree frog.
abstract: In frogs, an important mechanism of skin innate immunity against invading microbial pathogens is secretion of antimicrobial peptides from the specialized granular glands. Since these glands develop fully in skin dermis after completion of metamorphosis, they are small and immature in skin of larvae (tadpoles). Skin secretions vary among different life stages. Antimicrobial activity and peptide composition of natural mixture of skin peptides of three different life stages of New Zealand Ewing's Tree Frog (Litoria ewingii), tadpoles, metamorphs and adults were analyzed. The peptide mixtures were collected from skin secretions and analyzed for activity against the standard reference bacterium, Escherichia coli (ATCC 25922). Their peptide components were analyzed using liquid chromatography mass spectrometry (LC-MS). The peptide mixture from adults and metamorphs contained the species-specific antimicrobial peptide uperin 7.1 and inhibited the growth of E. coli (ATCC 25922). In contrast, the peptide mixture of tadpoles did not inhibit the growth of E. coli (ATCC 25922). This peptide mixture did not contain uperin 7.1 but had peptides whose molecular masses did not correspond to molecular masses of any known frog antimicrobial peptides.
authors.affiliation: School of Biological Sciences, University of Canterbury, Christchurch, New Zealand. ermins@gmail.com
authors.forename: Ermin
authors.initials: E
authors.lastname: Schadich
authors.forename: Anthony L J
authors.initials: AL
authors.lastname: Cole
authors.forename: Marie
authors.initials: M
authors.lastname: Squire
authors.forename: Drusilla
authors.initials: D
authors.lastname: Mason
mesh_terms: D029845:Amphibian Proteins / Q000302:isolation & purification*; D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000302:isolation & purification* / Q000494:pharmacology; D001001:Anura / Q000254:growth & development*; D002853:Chromatography, Liquid; D004926:Escherichia coli / Q000254:growth & development; D012867:Skin / Q000737:chemistry / Q000254:growth & development*; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D029845:Amphibian Proteins; D023181:Antimicrobial Cationic Peptides