title: Gene expression and distribution of antibacterial L-amino acid oxidase in the rockfish Sebastes schlegeli.
abstract: Antibacterial factors in the epidermal mucus of fish have a potential importance in the first line of the host defense response to bacterial pathogens. We previously isolated a novel antibacterial protein termed SSAP (Sebastes schlegeli antibacterial protein) from the skin mucus of the rockfish S. schlegeli and identified it as a new member of the L-amino acid oxidase (LAO) family. In the present study, the localization of SSAP in S. schlegeli was investigated by reverse transcription (RT)-PCR, quantitative real time RT-PCR, Western blotting and measurements of LAO and antibacterial activities. SSAP mRNA was expressed dominantly in skin and gill and weakly in ovary or kidney as shown by RT-PCR and real time RT-PCR. The quantity of SSAP mRNA in skin varied among the individuals, ranging from 1.1 to 13.9 ng microg(-1) total RNA, although no relationship was found between the size of fish and gene expression. SSAP was exclusively detected in skin and gill by Western blotting using a specific anti-SSAP antiserum. In addition, the extracts of both tissues apparently showed LAO activity and antibacterial activity against Photobacterium damselae subsp. piscicida. This study demonstrates that SSAP is predominantly synthesized in skin and gill and probably functions as an antibacterial LAO in both tissues.
authors.affiliation: Department of Food Science and Technology, Tokyo University of Marine Science and Technology, Konan 4-5-7, Minato, Tokyo 108-8477, Japan.
authors.forename: Yoichiro
authors.initials: Y
authors.lastname: Kitani
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Mori
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nagai
authors.forename: Keiko
authors.initials: K
authors.lastname: Toyooka
authors.forename: Shoichiro
authors.initials: S
authors.lastname: Ishizaki
authors.forename: Kuniyoshi
authors.initials: K
authors.lastname: Shimakura
authors.forename: Kazuo
authors.initials: K
authors.lastname: Shiomi
authors.forename: Yuji
authors.initials: Y
authors.lastname: Nagashima
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D015153:Blotting, Western; D005399:Fishes / Q000235:genetics / Q000378:metabolism*; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000276:immunology*; D005880:Gills / Q000201:enzymology; D006861:Hydrogen Peroxide / Q000378:metabolism; D050830:L-Amino Acid Oxidase / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D010776:Photobacterium / Q000187:drug effects; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012867:Skin / Q000201:enzymology
chemical_list: D000900:Anti-Bacterial Agents; D006861:Hydrogen Peroxide; D050830:L-Amino Acid Oxidase