title: A piscidin-like antimicrobial peptide from the icefish Chionodraco hamatus (Perciformes: Channichthyidae): molecular characterization, localization and bactericidal activity.
abstract: Antimicrobial peptides (AMPs) are considered one of the most ancient components of the innate immune system. They are able to exert their protection activity against a variety of microorganisms, and are widely distributed in both vertebrates and invertebrates. In this paper we focused on an AMP identified in the Antarctic teleost Chionodraco hamatus, an icefish species. The cDNA sequence of the AMP, named chionodracine, is comprised of 515 bp and translates for a putative protein precursor of 80 amino acids, with a signal peptide of 22 amino acids. The structural features evidenced in the primary sequence of chionodracine lead to the inclusion of the peptide in the antimicrobial family of piscidins. The analysis by real-time PCR of the basal gene transcripts of chionodracine in different icefish tissues showed that the highest expression was found in gills, followed by head kidney. The chionodracine expression levels in head kidney leukocytes were up-regulated in vitro both by LPS and poly I:C, and in vivo by LPS. A putative chionodracine mature peptide was synthesized and employed to obtain a polyclonal antiserum, which was used in immunohistochemistry of gills sections and revealed a significant positivity associated with mast cells. The bactericidal activity of the peptide was investigated and found significant against Antarctic psychrophilic bacteria strains (Psychrobacter sp. TAD1 and TA144), the Gram-positive Bacillus cereus, and at a lesser extent against the Gram-negative Escherichia coli. Interestingly, the haemolytic activity of chionodracine was tested in vitro on human erythrocytes and no significant lysis occurred until peptide concentration of 50 μM.
authors.affiliation: Department for Innovation in Biological, Agro-food and Forest Systems, University of Tuscia, Largo dell'Università, 01100 Viterbo, Italy. fbuono@unitus.it
authors.forename: Francesco
authors.initials: F
authors.lastname: Buonocore
authors.forename: Elisa
authors.initials: E
authors.lastname: Randelli
authors.forename: Daniela
authors.initials: D
authors.lastname: Casani
authors.forename: Simona
authors.initials: S
authors.lastname: Picchietti
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Belardinelli
authors.forename: Donatella
authors.initials: D
authors.lastname: de Pascale
authors.forename: Concetta
authors.initials: C
authors.lastname: De Santi
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Scapigliati
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000864:Antarctic Regions; D023181:Antimicrobial Cationic Peptides / Q000235:genetics* / Q000378:metabolism*; D001483:Base Sequence; D017931:DNA Primers / Q000235:genetics; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D004912:Erythrocytes / Q000187:drug effects; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects / Q000276:immunology*; D005880:Gills / Q000378:metabolism; D060226:Head Kidney / Q000378:metabolism; D006461:Hemolysis / Q000276:immunology; D006801:Humans; D007150:Immunohistochemistry / Q000662:veterinary; D008070:Lipopolysaccharides / Q000633:toxicity; D008969:Molecular Sequence Data; D010473:Perciformes / Q000235:genetics / Q000276:immunology*; D011070:Poly I-C / Q000633:toxicity; D060888:Real-Time Polymerase Chain Reaction; D017422:Sequence Analysis, DNA
chemical_list: D023181:Antimicrobial Cationic Peptides; D017931:DNA Primers; D008070:Lipopolysaccharides; D011070:Poly I-C