Nocardioides exalbidus sp. nov., a novel actinomycete isolated from lichen in Izu-Oshima Island, Japan
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A short coccoid- or rod-shaped, non-motile actinomycete strain RC825<SUP>T</SUP> was isolated from lichen in Izu-Oshima Island, Japan. A polyphasic study was undertaken to establish the taxonomic position of this strain. Phylogenetic analysis based on 16S rRNA gene sequence revealed that strain RC825<SUP>T</SUP> forms an evolutionary lineage within the radiation of the genus <I>Nocardioides</I>. In particular, it forms a coherent cluster with <I>Nocardioides oleivorans</I> and <I>Nocardioides ganghwensis</I> with high sequence similarity of 98 and 97.5%, respectively. However, DNA–DNA hybridization experiment demonstrated that strain RC825<SUP>T</SUP> is distinct from its closest phylogenetic neighbors, <I>N. oleivorans</I> and <I>N. ganghwensis</I>, with 44 and 39% relatedness, respectively. The cell-wall peptidoglycan of strain RC825<SUP>T</SUP> contained <SMALL>LL</SMALL>-diaminopimelic acid, indicating wall chemotype I. The predominant menaquinone was MK-8(H<SUB>4</SUB>). Strain RC825<SUP>T</SUP> had a cellular fatty acid profile containing straight-chain, branched, unsaturated and 10-methyl fatty acids, and the major fatty acid was iso-C<SUB>16:0</SUB>. The DNA G+C content of the strain was 74 mol%. On the basis of both phenotypic and phylogenetic evidence, the strain is separated from previously described <I>Nocardioides</I> species, and should be assigned to represent a novel species of the genus <I>Nocardioides</I>, for which the name <I>Nocardioides exalbidus</I> sp. nov. is proposed. The type strain is strain RC825<SUP>T</SUP> (=IAM 15416<SUP>T</SUP>=CCTCC AA206016<SUP>T</SUP>).
Actinomycetologica 21(1), 22-26, 2007-06-25
The Society for Actinomycetes Japan