Studies on Anti-disease Factors Produced by Fish Intestinal Bacteria

对鱼类肠道细菌产生的抗病因子进行了研究，得到以下结果：养殖日本比目鱼海水中的弧菌主要来源于鱼肠和粪丸。从沿海鱼类肠道中分离的梭状芽孢杆菌和革兰氏阳性厌氧球菌似乎对鱼类肠道内的环境具有适应性。从鱼肠、水和沉积物中分离的细菌中，有1.0 ~ 15%的菌株对鱼致病菌具有抗菌活性。由弧菌sp. nm10和芽孢杆菌sp. nm14产生的抗菌物质分别为蛋白质物质和铁载体。88-94%的分离气单胞菌产生醋酸，这可能是一种抗菌物质。许多气单胞菌属和弧菌分离株至少产生两种类型的蛋白酶，丝氨酸蛋白酶和金属蛋白酶。从牙鲆幼虫和幼鱼分离的弧菌中约有10%产生神经氨酸酶。

Anti-disease factors produced by fish intestinal bacteria were investigated and the following results were obtained:1. Most Vibrio bacteria in Japanese flounder-rearing seawater were suggested to derive from fish intestines via fecal pellets.2. Clostridia and gram-positive anaerobic cocci isolated from coastal fish intestines seem to adapt to the environment inside intestinal tracts of fish.3. Of bacteria derived from fish intestines, water and sediments, 1.0-15% of isolates showed antibacterial activities against fish pathogenic bacteria.4. Antibacterial substances produced by Vibrio sp. NM 10 and Bacillus sp. NM 14 were a proteinous substance and a sideerophore, respectively.5. As many of 88-94% of Aeromonas isolates produced acetic acid, which may be an antibacterial subtance.6. Many isolates of genera Aeromonas and Vibrio produced at least two types of protease, serine protease and metalloprotease.7. About 10% of vibrios isolates from larvae and juveniles of Japanese flounder produced neuraminidase.