SGM Journals
Research Article

Sporichthya brevicatena sp. nov.

Tamura, Tomohiko, Hayakawa, Masayuki, Hatano, Kazunori

International Journal of Systematic Bacteriology 1999; 49(4):1779 · https://doi.org/10.1099/00207713-49-4-1779

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Summary auto-generated

Researchers isolated a novel actinomycete strain (YU720-21T) from Japanese soil that produces short chains of aerial spores without substrate mycelium. Morphological and chemotaxonomic analyses revealed the organism belongs to the genus Sporichthya, characterized by LL-diaminopimelic acid in cell walls, menaquinone 9(H8) as the major quinone, and 71 mol% DNA G+C content. Phylogenetic analysis based on 16S rDNA sequences confirmed its placement within Sporichthya with 99% similarity to the known species S. polymorpha. However, DNA-DNA hybridization demonstrated only 20-28% relatedness to S. polymorpha, establishing it as a distinct species. The new isolate differs from S. polymorpha in carbon source utilization patterns, menaquinone composition ratios, and cellular fatty acid profiles. The authors propose this strain as a new species, Sporichthya brevicatena sp. nov., with the type strain designated YU720-21T (IFO 16195T). This work expands the known diversity within the genus Sporichthya, previously containing only a single recognized species.

Key findings

  • Strain YU720-21T represents a new Sporichthya species, S. brevicatena, distinguished from S. polymorpha by DNA-DNA hybridization showing only 20-28% relatedness
  • The organism lacks substrate mycelium but produces short aerial spore chains with motile spores, containing LL-diaminopimelic acid cell walls and 71 mol% G+C DNA content
  • Phylogenetic analysis based on 16S rDNA sequences confirms placement in genus Sporichthya with monophyletic clustering to S. polymorpha, supported by 100% bootstrap confidence
  • Differential chemotaxonomic characteristics distinguish S. brevicatena including different menaquinone composition ratios and cellular fatty acid profiles compared to S. polymorpha

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Abstract

A strain was isolated from soil that formed short chains of aerial mycelium dividing into motile spores on an agar medium, but not substrate mycelium. The organism had menaquinone 9(H8), LL-diaminopimelic acid in the cell wall amino acids and a DNA G+C content of 71 mol%. On the basis of the morphological and chemotaxonomic characteristics and phylogenetic analysis, this strain was classified into the genus Sporichthya. DNA-DNA hybridization revealed that the strain differed from the known species, Sporichthya polymorpha. Therefore, a new species, Sporichthya brevicatena sp. nov., is proposed. The type strain is S. brevicatena YU720-21T (= IFO 16195T).