紫色非硫细菌Rhodocista属一新分离株的鉴定及其系统学研究

从污水处理厂分离到一株紫色非硫细菌３－ｐ，该菌株具避光性，能形成孢囊，具片层状光合内膜，在波长７９８ｎｍ处的吸收峰很低，需硫胺素和维生素Ｂ１２作生长因子。该菌株可以琥珀酸为碳源，最佳生长温度为３４℃～４１℃，体内未发现Ｒ体结构，醌类的主要成分是Ｑ－９。对菌株３－ｐ的１６Ｓ ｒＲＮＡ基因的分子系统学分析结果表明，菌株３－ｐ与世纪红蒌菌（Ｒｈｏｄｏｃｉｓｔａ ｃｅｎｔｅｎａｒｉａ）关系最近，相似性为９

CHARACTERIZATION AND PHYLOGENIC ANALYSIS ON A NEW ISOLATE OF GENUS RHODOCISTA

A strain of purple non sulfur bacteria was isolated from waste water plant in Beijing. It is phototaxic, and can converted the vibrioid cells into thick-wall cyst. Internal synhetic membrane is present as lamellae. It has a low absorption maxima at 798 nm. and require thiamine and vitamin B12 as growth factors. It can use succinate as carbon and energy source, but glucose can not be used. It can not grow in 3% NaC1 and had Q-9 as major quinone. The 16S rRNA gene was amplified, cloned and sequenced. A phylogenic tree was constructed on the basis of the 16S rDNA sequences. It showed that the previously known member of the genus Rhodocista, Rc. centenaria, is the nearest neighbor to strain 3-p. The level of binary sequence similarity between Rc. centenaria and strain 3-p of 95 %, and their phenotypic differences and genetic DNA-DNA relatedness of 56 %, shows they are different species of Rhodocista. A new species name, Rhodocista pekinense, was proposed for strain 3-p.