[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 synthetic 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% NaCl 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.