降解有毒的含羞草素和二羟基吡啶化合物的瘤胃细菌

从采食银合欢不引起中毒症状的我国广西北海市涠洲岛的黄牛瘤胃中,分离出4株厌氧细菌.经高效液相色谱分析证实,菌株BR-1,BR-2,BR-5和BR-7能降解有毒的含羞草素(mimosine)、3-羟基-4(1氢)吡啶酮(3,4 DHP)和2,3-二羟基吡啶(2,3DHP).在宿主体外进行纯菌和混菌液体培养,3天分别降解含羞草素44—59%,3,4DHP 30—47%和2,3DHP58—60%.经分类鉴定,确定为三个种:BR-1和BR-2很相似,为乳杆菌属(Lactobacillus),可能是一个新种.BR-5为牛链球菌(Streptococcus bovis)和BR-7为生孢梭菌(Clostridiumsporogenes).上述这些兼性和严格厌氧的革兰氏阳性细菌对含羞草素和二羟基吡啶类毒素具有降解活性,这是以前没有报道过的.由于这些脱毒细菌栖居于瘤胃的微生态系统中,从而保护宿主动物免受银合欢的毒害.

RUMEN BACTERIA DEGRADING TOXIC MIMOSINE AND DIHYDROXYPYRIDINE COMPOUNDS IN CHINA

Four anaerobic strains were isolated from the rumen of the cattle which no specific toxic symptoms were seen when Leucaena was fed in Weizhou island Beihai city, Guangxi Province, China. All of these strains (BR-1, BR-2, BR-5 and BR-7) possess degradative activities to toxic mimosine?3-hydroxy-4 (1H) -pyridone (3, 4-DHP) and 2, 3-dihydroxypyridine (2, 3DHP) from Leucaena, that were confirmed by analysis of HPLC. Pure and mixed cultures of these four strains in vitro degraded 44-59% of mimosine, 30-47% of 3, 4 DHP, and 58-60% of 2, 3 DHP respectively in 3 days. Strains of Both BR-1 and BR-2 were almost identical and were characterized as Lactobacillus, may be a new species. Strains of BR-5 and BR-7 were characterized as Streptococcus bovis and Clostridium sporogenes respectively. It has not yet been reported that these Gram positive facultatively and obligately anaerobic b tetria wore able to degrade mimosine, 3, 4 DHP and 2, 3 DHP. These detoxic bact existing in the rumen microflora of cattle in Weizhou island, protecting thereface,their hosts animal from Leucaena toxicity.