中文摘要：

从青海湖采集20份水样，利用RM高盐培养基分离获得35株嗜盐菌．选取其中一株优势中度嗜盐菌QHL25进行形态学和生理生化特征分析，结果表明：QHL25菌落圆形或椭圆形，乳白色，不透明，中心突出，边缘透明，生长盐度为0~2．9mol／L，最适生长盐度为1．45mol／L．显微形态呈短杆状，革兰氏染色呈阴性，单个或成串排列．最适生长pH为8．5，最适生长温度为37℃．16SrDNA序列分析表明：该菌株与盐单胞菌属（Halomonassp．）相似性为98％；结合形态特征和生理生化特征分析，初步认定该菌株隶属于y变形杆菌纲（Gammaproteobacteria）海洋螺菌目（Oceanospirillales）盐单胞菌科（Holomonadaceae）盐单胞菌属（Holomonas）．薄层层析（TLC）定性分析可知QHL25胞内含有相容溶质四氢嘧啶；高效液相色谱（HPLC）定量分析表明，在1．7mot／L的NaCl度下，四氢嘧啶含量约为36．70mg儋（细胞干重）．

英文摘要：

Thirty-five strains of halophiles were isolated from 20 water samples of the Qinghai Lake by a RM medium with high salinity. The moderate halophile QHL25 was selected and studied phenotypically, physiologically and phylogenetically. On the basis of its morphological and physiological characteristics, the isolate was round or oval-shaped, white and opaque as a single cell or in clusters. It was a Gram-negative rod that was able to grow at the salt concentration ranging from 0 to 2.9 mol/L （an optimum of 1.45 tool/L）. The optimum pH and temperature for growth were 8.5 and 37 ~2 respectively. Based on the 16S rDNA gene sequence analysis, the halophile QHL25 had a 98% similarity with Halomonas sp. K1B-11. According to its morphological, physiological and biochemical characteristics combined with the sequence analysis of the 16S rDNA, strain QHL25 was preliminarily identified as a member of the genus Holomonas, which belonged to Oceanospirillales order of Gammaproteobacteria class. The intracellular compatible solute of ectoine accumulated in QHL25 could be detected by thin- layer chromatography and the content of ectoine was determined as 36.70 mg/g （cell dry weight） by high-performance liquid chromatography in the presence of 1.7 mol/L NaCl.