Actinomyces capricornis sp. nov., isolated from the oral cavity of a Japanese serow.

A novel Gram-positive, facultatively anaerobic, rod-shaped, nonspore forming, nonmotile organism was isolated from a Japanese serow oral cavity. Designated strain MAS-1T , it is most closely related to Actinomyces bowdenii DSM 15435T , with which it shares 98.07% sequence homology in the 16S ribosomal RNA gene. The primarily detected cellular fatty acids in strain MAS-1T were C16:0 and C18:1 w9c. The predominant respiratory quinone was MK-9 (H4 ). The major polar lipids were phosphatidylcholines, phosphatidylinositols, and glycophospholipids. The genomic DNA GC content of the isolate was 71.3 mol%. The digital DNA-DNA hybridization and average nucleotide identity values between MAS-1T and its related species were 23.5%-39.5% and 82.11%-91.01%, respectively, which were below the threshold (70% and 95%, respectively) for species delineation, indicating that strain MAS-1T represents a novel species. Strain MAS-1T can be differentiated from A. bowdenii by their reactions to naphthol-AS-BI-phosphohydrolase, α-galactosidase, β-galactosidase, and N-acetyl-β-glucosaminidase, as well as differing acid production from glycogen. Based on the results of genotypic, phenotypic, and biochemical analyses, herein it is proposed that the identified bacteria can be classified as a novel species, Actinomyces capricornis sp. nov., strain MAS-1T (=JCM 34236T  = DSM 111732T ).