奶牛瘤胃中1株反-11-油酸氢化菌的筛选及鉴定  

Screening and Characterization of trans-11 18:1 Hydrogenating Bacteria from Rumen of Dairy Cows

作　　者：卢玉飞[1,2] 王加启[1] 赵圣国[1] 卜登攀[1] 周凌云[1] 孙鹏[1] 

机构地区：[1]中国农业科学院北京畜牧兽医研究所动物营养学国家重点实验室,北京100193 [2]扬州大学动物科学与技术学院,扬州225009

出　　处：《畜牧兽医学报》2014年第1期69-77,共9页ACTA VETERINARIA ET ZOOTECHNICA SINICA

基　　金：国家"973"计划项目(2011CB100804);中央级公益性科研院所基本科研业务费专项资金项目(2010jc-3-2)

摘　　要：本试验旨在分离荷斯坦奶牛瘤胃中反-11-油酸(tranan5-ll 18:1,t-VA)氢化菌,研究鉴定其生化性质和种属分类地位。将富集的t-VA氢化菌群,通过厌氧平板分离培养,筛选出氢化率高的菌株,利用全自动微生物分析系统的革兰氏阳性菌鉴定卡鉴定该菌的生化图谱。对该菌16S rDNA及3种功能性基因sodA、rpoB与recN进行PCR扩增并测序,与GenBank数据库中序列进行同源性比对,确定其种属分类地位。通过体外厌氧培养,从瘤胃中分离得到t-VA氢化率高达82.1%的菌株,命名为RV,革兰氏染色为阳性,细胞呈现球状或卵圆形,最佳生长温度和pH分别为39℃和6.0~7.8,绝对厌氧,生化性质包括能降解多种单糖和多糖作为能量来源,耐受部分抗生素和具有多种酶的活性等。由革兰氏阳性生化图谱发现,该菌与猪肠链球菌的生化图谱相似度为99%。RV菌的16S rDNA序列与牛链球菌和马链球菌16S rDNA的相似度为99%~100%。功能性基因sodA、rpoB和recN序列与牛链球菌的相似度分别为99%、99%和98%。本试验从瘤胃中筛选获得一株具有较高t-VA氢化能力的牛链球菌,是一株具有研究和潜在应用价值的氢化菌菌株。The purpose of this study was to identify trans-vaccenic acid(trans-11 C18:1,t-VA)hydrogenating bacteria in vitro from rumen of dairy cows and to analyze biochemistry characteristics and phylogenetic position.The t-VA-hydrogenating bacterium was isolated from the rumen of Holstein dairy cows based on enrichment culture under anaerobic conditions.The strains with high degree of hydrogenation were screened.The biochemical map were detected by gas chromatograph and the biochemical characterization of RV was analyzed by VITEK 2 compact system.The16S rDNA,sod A,rpoB and recN genes were sequenced and used for phylogenic tree building.The newly isolate bacteria named RV with t-VA hydrogenating efficiency of 82.1%was isolated.RV was strictly anaerobic,gram-staining-positive,globose or oval shaped,and had optimum growth performance at 39 'Cand pH 6.0-7.8.The carbon or energy sources of RV came from D-xylose,D-galactose,D-maltose,D-mannose,pullulan,sacchrose,D-trehalose,D-cellobiose,etc.It contained some enzyme activities(e.g alpha-galactosidase and arylamidase) and resistant phylotpye to bacitracin,novobiocin,polymixin B.The gram-positive biochemical map showed that the similarity of RV reached 99%to that of pig intestine Streptococcus.The sequence of 16S rDNA of RV had high identity to Streptococcus equinus and Streptococcus bovis(99%-100%).The sequence of the funtional genes(sodA,rpoB and recN) had the hightest homology to S.bovis(99%,99%and98%).One t-VA hydrogenating bacteria(a strain from S.bovis) named RV is isolated from rumen.To our known,this is the first study to find that S.bovis has t-VA hydrogenating activity.

关 键 词：分离 氢化菌 牛链球菌 反-11-油酸 瘤胃 

分 类 号：S823[农业科学—畜牧学]