Actinoplanes rishiriensis sp. nov., a novel motile actinomycete isolated by rehydration and centrifugation method

Abstract

The motile actinomycete strain RI50-RCA114(T) was isolated using rehydration and centrifugation method from a soil sample obtained from Rishiri Island in Japan. The taxonomic status of this organism was established using a polyphasic approach. Cells of strain RI50-RCA114(T) were Gram positive, aerobic, motile and formed irregular sporangia. The strain grew in the presence of 0-2% (w/v) NaCl, between pH 5 and 8, and over a temperature range of 20-37°C, with optimal growth at 30°C. Whole-cell hydrolysates of the strain contained meso-diaminopimelic acid, galactose, glucose and mannose, in addition to one unidentified O-methyl-hexose. The predominant menaquinone was MK-9(H(4)), and the major polar lipids comprised phosphatidylethanolamine, diphosphatidylglycerol and phosphatidyl-N-methylethylethanolamine. The major cellular fatty acids were iso-C(16:0), iso-C(15:0) and anteiso-C(17:0). Comparative 16S ribosomal RNA gene sequence analysis revealed that strain RI50-RCA114(T) had the closest sequence similarity with Actinoplanes globisporus JCM 3186(T) (97.6%). However, DNA-DNA hybridization assays as well as physiological and biochemical analyses differentiated strain RI50-RCA114(T) from its closest phylogenetic relative. On the basis of these data, we propose that strain RI50-RCA114(T) (=NBRC 108556(T)=BCC 49184(T)) be classified as the type strain of a novel Actinoplanes species and named Actinoplanes rishiriensis sp. nov.