title: Molecular cloning and multifunctional characterization of host defense peptides from the bullfrog Harderian gland with special reference to catesbeianalectin.
abstract: The Harderian gland (HG) is an orbital gland found in many terrestrial vertebrates that possess a nictitating membrane. Using reverse-transcription polymerase chain reaction (RT-PCR), we cloned five cDNAs encoding antimicrobial peptide (AMP)-homologs, catesbeianalectin, ranacyclin-CBa, ranatuerin-1CBa, ranatuerin-2CBa, and ranatuerin-2CBb, from the bullfrog HG total RNA. Of these, catesbeianalectin has not been thoroughly studied in terms of its biological activities. We examined antimicrobial activities of the synthetic replicate of catesbeianalectin and its putative unprocessed precursor, catesbeianalectin-GK. Both peptides showed slight but significant growth inhibitory activity against the Gram-negative bacterium Escherichia coli. Subsequently, we tested catesbeianalectin and catesbeianalectin-GK for mast cell degranulation activity as a criterion of the release of N-acetyl-β-D-glucosaminidase from the mouse-derived mastocytoma cell line P-815, followed by the standard MTT assay to assess cell survival and recovery after peptide treatment. We found that catesbeianalectin and catesbeianalectin-GK invariably exhibited mast cell degranulation activity without cytotoxic effects. Hemagglutination assay revealed the presence of lectin-like activity in both catesbeianalectin and catesbeianalectin-GK. Our findings strongly suggest that these multifunctional host defense peptides in the amphibian HG are involved in innate immunodefense of the eye of the host against pathogenic environmental microorganisms.
authors.affiliation: Department of Biology, Faculty of Science, Toho University, 2-2-1 Miyama, Funabashi, Chiba 274-8510, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Konishi
authors.forename: Shawichi
authors.initials: S
authors.lastname: Iwamuro
authors.forename: Itaru
authors.initials: I
authors.lastname: Hasunuma
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Sakae
authors.initials: S
authors.lastname: Kikuyama
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D002460:Cell Line; D002470:Cell Survival; D003001:Cloning, Molecular; D005786:Gene Expression Regulation / Q000502:physiology*; D006243:Harderian Gland / Q000502:physiology*; D037102:Lectins / Q000378:metabolism*; D051379:Mice; D058977:Molecular Sequence Annotation; D011892:Rana catesbeiana / Q000502:physiology*
chemical_list: D023181:Antimicrobial Cationic Peptides; D037102:Lectins