1株小鼠肠道酵母菌的分离与鉴定

Isolation and identification of a yeast strain from intestine of mice

为研制新型微生态制剂,从试验小鼠中分离出1株肠道酵母菌,采用形态学、生理生化、基因测序和系统发育树分析等方法对其进行鉴定。结果显示,该菌菌落呈白色、圆形,在显微镜下细胞呈椭圆形,出芽生殖;该菌能发酵葡萄糖、蔗糖和D–甘露醇,能够同化蛋白胨和硝酸钾,不能耐受高浓度乙醇,脲酶试验结果为阴性。序列分析结果表明,该菌株18SrDNA(登录号为KC534843)与汉逊德巴利酵母(Debaryomyces hansenii)18SrDNA(登录号为AB013567)的同源性达99%,26SrDNA(登录号为KC534842)与汉逊德巴利酵母(Debaryomyces hansenii)26SrDNA(登录号为EU131182)的同源性达99%。系统发育树分析结果显示,该菌株18SrDNA与Debaryomyces hansenii(登录号为AB013590)的亲缘关系最近,26SrDNA与Debaryomyces hansenii(登录号为EU131182)的亲缘关系最近。由以上结果可推断该菌为汉逊德巴利酵母。

In order to develop a new type of probiotics, a yeast strain was isolated from intestine of mice, and it wasidentified using the methods of morphology, physiology, biochemistry, gene sequencing and phylogenetic tree. Theresults showed that the bacterial colony presented in white milky color and oval shape. Through microscopic observation,we found its cell presented in oval shape, and the asexual reproduction was gemmation. The yeast could ferment glucose,sucrose and D–mannitol, as well as assimilate peptone and potassium nitrate, while, it could not tolerate highconcentration of alcohol, and the urease test was negative. The results from 18S rDNA sequencing analysis showed thatDNA homology of the strain (Accession No. KC534843) and Debaryomyces hansenii (Accession No. AB013567)reached up to 99%, moreover, 26S rDNA sequencing analysis showed that the homology between the strain (AccessionNo. KC534842) and Debaryomyces hansenii (Accession No. EU131182) was also 99%. From the result of phylogenetic tree showed that 18s rDNA gene sequence of the strain was closest to Debaryomyces hansenii (Accession No.AB013590), and 26S rDNA gene sequence of the strain was closest to Debaryomyces hansenii (Accession No.EU131182). We could draw the conclusion that the yeast strain was Debaryomyces hansenii.