title: A mannose-specific tetrameric lectin with mitogenic and antibacterial activities from the ovary of a teleost, the cobia (Rachycentron canadum).
abstract: A tetrameric lectin, with hemagglutinating activity toward rabbit erythrocytes and with specificity toward D-mannosamine and D(+)-mannose, was isolated from the ovaries of a teleost, the cobia Rachycentron canadum. The isolation protocol comprised ion exchange chromatography on CM-cellulose and Q-Sepharose, ion exchange chromatography by fast protein liquid chromatography (FPLC) on Mono Q, and finally gel filtration by FPLC on Superose 12. The lectin was adsorbed on all ion exchangers used. It exhibited a molecular mass of 180 kDa in gel filtration on Superose 12 and a single 45-kDa band in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, indicating that it is a tetrameric protein. The hemagglutinating activity of the lectin was stable up to 40 degrees C and between pH 4 and pH 10. All hemagglutinating activity disappeared at 60 degrees C and at pH 1 and pH 13. The hemagglutinating activity was doubled in the presence of 0.1 microM FeCl3. The lectin exerted antibacterial activity against Escherichia coli with 50% inhibition at 250 microg. There was no antifungal activity toward Coprinus comatus, Fusarium oxysporum, Mycosphaerella arachidicola, and Rhizoctonia solani at a dose of 300 microg. The lectin exhibited maximal mitogenic response from mouse splenocytes at a concentration of 14 microM.
authors.affiliation: Department of Biochemistry, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China.
authors.forename: Patrick H K
authors.initials: PH
authors.lastname: Ngai
authors.forename: T B
authors.initials: TB
authors.lastname: Ng
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D049109:Cell Proliferation / Q000187:drug effects; D004926:Escherichia coli / Q000187:drug effects; D005260:Female; D006386:Hemagglutination Tests; D037241:Mannose-Binding Lectins / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D051379:Mice; D008826:Microbial Sensitivity Tests; D008934:Mitogens / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D010053:Ovary / Q000737:chemistry*; D010473:Perciformes / Q000033:anatomy & histology*; D011817:Rabbits; D013154:Spleen / Q000166:cytology / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D037241:Mannose-Binding Lectins; D008934:Mitogens