埃氏巨型球菌及其乙酸生成关键酶基因缺失工程菌体外代谢特性的初步研究  

Metabolic Characterization of Megasphaera Elsdenii and its Gene Deletion Engineering Bacteria in vitro

作　　者：孙国权[1,2] 刘国文[1] 邢欣[1] 逄晓阳[1,3] 龙淼[1] 苑学[2] 杨文艳[4] 王哲[1] 

机构地区：[1]吉林大学畜牧兽医学院,长春130062 [2]内蒙古民族大学动物科技学院,通辽028042 [3]吉林省产品质量监督检验院,长春130022 [4]吉林农业大学动物科技学院,长春130118

出　　处：《中国畜牧兽医》2010年第4期26-29,共4页China Animal Husbandry & Veterinary Medicine

基　　金：国家自然科学基金资助项目(30600441,30230260)

摘　　要：埃氏巨型球菌是奶牛瘤胃中的一种优势菌。本研究运用瘤胃微生态理论,结合埃氏巨型球菌能利用乳酸发酵产生丙酸的特点,初步研究埃氏巨型球菌(H6)及其乙酸生成关键酶基因缺失工程菌(TnH6)体外发酵特性。经健康羊瘤胃液体外连续培养结果表明,埃氏巨型球菌及其乙酸生成关键酶基因缺失工程菌均能利用乳酸生成VFA,发酵生成的VFA以丙酸为主,发酵类型倾向于丙酸型,但工程菌生成乙酸的能力明显降低,尽管丙酸生成能力有所下降,但显著降低了乙酸与丙酸的比例,从而为调控瘤胃乳酸发酵和利用H6、TnH6防治奶牛亚临床性瘤胃乳酸酸中毒提供了理论和试验基础。Megasphaera elsdenii is one of dominant bacteria in the rumen.In according to the characteristic of energy metabolism for the ruminant,that is energy supply through the volatile fatty acids such as acetate,propionate,butyrate generated by fermentation of microorganism in rumen,and the theory of ruminal fermentated regulation,which is mainly to regulate the degradation of lactate and the production of propionate.Primary substrates（lactic acid and pyruvate） were cocultured with H6 and TnH6 for 48 h,respectively,in order to observe the fermentation of ruminal fluid in vitro.Culture fluid was sampled for analysis of pH and VFA.The results showed that the lactate in the culture fluid was utilized by the strains of H6 and TnH6.Compared to strains H6,the acetate concentrations and the ratio of acetate to propionate were obviously reduced in the culture fluid of the strain TnH6,even though the concentration of propionate was slightly reduced.The results suggested that the transponed engineering bacteria TnH6 belonged to a deleted strain of acetic acid-producing gene and it could lay a foundation of developing a new micro ecosystem preparation for prevention and control of the diseases in periparturient dairy cows.

关 键 词：埃氏巨型球菌 乳酸发酵 代谢特性 

分 类 号：S852.6[农业科学—基础兽医学]