title: Identification of a novel cathelicidin antimicrobial peptide from ducks and determination of its functional activity and antibacterial mechanism.
abstract: The family of antimicrobial peptide, cathelicidins, which plays important roles against infections in animals, has been identified from many species. Here, we identified a novel avian cathelicidin ortholog from ducks and named dCATH. The cDNA sequence of dCATH encodes a predicted 146-amino-acid polypeptide composed of a 17-residue signal peptide, a 109-residue conserved cathelin domain and a 20-residue mature peptide. Phylogenetic analysis demonstrated that dCATH is highly divergent from other avian peptides. The α-helical structure of the peptide exerted strong antimicrobial activity against a broad range of bacteria in vitro, with most minimum inhibitory concentrations in the range of 2 to 4 μM. Moreover, dCATH also showed cytotoxicity, lysing 50% of mammalian erythrocytes in the presence or absence of 10% fetal calf serum at concentrations of 32 μM or 20 μM and killing 50% HaCaT cells at a concentration of 10 μM. The effects on bacterial outer and inner membranes, as examined by scanning electron microscope and transmission electron microscopy, indicate that dCATH kills microbial cells by increasing permeability, causing a loss of membrane integrity.
authors.affiliation: College of Animal Science and Technology, Northeast Agricultural University, Harbin 150030, P.R. China.
authors.forename: Wei
authors.initials: W
authors.lastname: Gao
authors.affiliation: College of Animal Science and Technology, Northeast Agricultural University, Harbin 150030, P.R. China.
authors.forename: Liwei
authors.initials: L
authors.lastname: Xing
authors.affiliation: College of Animal Science and Technology, Northeast Agricultural University, Harbin 150030, P.R. China.
authors.forename: Pei
authors.initials: P
authors.lastname: Qu
authors.affiliation: College of Animal Science and Technology, Northeast Agricultural University, Harbin 150030, P.R. China.
authors.forename: Tingting
authors.initials: T
authors.lastname: Tan
authors.affiliation: College of Animal Science and Technology, Northeast Agricultural University, Harbin 150030, P.R. China.
authors.forename: Na
authors.initials: N
authors.lastname: Yang
authors.affiliation: College of Animal Science and Technology, Northeast Agricultural University, Harbin 150030, P.R. China.
authors.forename: Dan
authors.initials: D
authors.lastname: Li
authors.affiliation: College of Animal Science and Technology, Northeast Agricultural University, Harbin 150030, P.R. China.
authors.forename: Huixian
authors.initials: H
authors.lastname: Chen
authors.affiliation: College of Animal Science and Technology, Northeast Agricultural University, Harbin 150030, P.R. China.
authors.forename: Xingjun
authors.initials: X
authors.lastname: Feng
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D023181:Antimicrobial Cationic Peptides; D001483:Base Sequence; D054804:Cathelicidins / Q000737:chemistry / Q000235:genetics / Q000494:pharmacology*; D016923:Cell Death / Q000187:drug effects; D002460:Cell Line; D002463:Cell Membrane Permeability / Q000187:drug effects; D004372:Ducks / Q000378:metabolism*; D004926:Escherichia coli / Q000187:drug effects / Q000648:ultrastructure; D006461:Hemolysis / Q000187:drug effects; D006801:Humans; D008564:Membrane Potentials / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D010802:Phylogeny; D016415:Sequence Alignment; D013211:Staphylococcus aureus / Q000187:drug effects / Q000648:ultrastructure
chemical_list: D000900:Anti-Bacterial Agents; D023181:Antimicrobial Cationic Peptides; D054804:Cathelicidins