Sphaerosporangium gen. nov., a new member of the family Streptosporangiaceae, with descriptions of three new species as Sphaerosporangium melleum sp. nov., Sphaerosporangium rubeum sp. nov. and Sphaerosporangium cinnabarinum sp. nov., and transfer of Streptosporangium viridialbum Nonomura and Ohara 1960 to Sphaerosporangium viridialbum comb. nov.
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The taxonomic status of five actinomycete strains, 3-28(8)<SUP>T</SUP>, 4-20(13), 3D-70(20), 5-81(36) and 3D-72(35)<SUP>T</SUP>, isolated from sandy soil was studied using the polyphasic approach. All isolates produced branching substrate mycelia and developed spherical spore vesicles on aerial hyphae containing non-motile spores. They contained <I>meso</I>-diaminopimelic acid and the <I>N</I>-acetyl type of peptidoglycan. The predominant menaquinones were MK-9(H<SUB>4</SUB>) and MK-9(H<SUB>6</SUB>). Madurose, mannose, ribose, galactose and glucose were detected in the whole-cell hydrolysate. The diagnostic phospholipids were phosphatidylethanolamine and ninhydrin-positive phosphoglycolipids, and iso-C<SUB>16:0</SUB> and 10 methyl C<SUB>17:0</SUB> were detected as the major cellular fatty acids. These morphological and chemotaxonomic data were related to those of the genus <I>Streptosporangium</I> in the family <I>Streptosporangiaceae</I>. Phylogenetic analysis based on 16S rDNA sequence data suggested that the strains belong to the family <I>Streptosporangiaceae</I>, but not to any known genus, and form a monophyletic clade with <I>Streptosporangium viridialbum</I> and "<I>Streptosporangium cinnabarinum</I>". The signature nucleotides of the members of this clade are different from those of any known genera of the family <I>Streptosporangiaceae</I>. On the basis of phylogenetic analysis and the characteristic patterns of signature nucleotides as well as the morphological and chemotaxonomic data, the genus <I>Sphaerosporangium</I> gen. nov. is proposed for our five isolates and the type strains of <I>Streptosporangium viridialbum</I> and "<I>Streptosporangium cinnabarinum</I>". DNA–DNA hybridization and phenotypic characterization indicate that the new genus comprises four species, <I>Sphaerosporangium melleum</I> sp. nov. with the type strain 3-28(8)<SUP>T</SUP> (=JCM 13064<SUP>T</SUP> =DSM 44954<SUP>T</SUP>), <I>Sphaerosporangium rubeum</I> sp. nov. with the type strain 3D-72(35)<SUP>T</SUP> (=JCM 13067<SUP>T</SUP> =DSM 44936<SUP>T</SUP>), <I>Sphaerosporangium cinnabarinum</I> sp. nov. (=JCM 3291 =DSM 44094) and <I>Sphaerosporangium viridialbum</I> comb. nov. (=JCM 3027<SUP>T</SUP> =DSM 43801<SUP>T</SUP>).
Actinomycetologica 21(1), 11-21, 2007-06-25
The Society for Actinomycetes Japan