摘要

A novel Gram-positive, aerobic, catalase-positive, filamentous micro-organism, designated strain IMMIB L-1269(T), originating from sputum was characterized using phenotypic and molecular taxonomic methods. It showed cell-wall chemotype III, phospholipid type PII (with phosphatidylethanolamine as the diagnostic phospholipid) and contained an unsaturated menaclumone with seven isoprene units (MK-7) as the predominant isoprenoid quinone. It synthesized long-chain cellular fatty acids of the straight-chain saturated, monounsaturated and iso- and anteiso-branched types (with iso-C(15:0), C(16:0) and iso-C(17:0) predominating) and possessed a DNA G + C content of 49.3 mol%. On the basis of its morphological, biochemical and chemical characteristics, strain IMMIB L-1269(T) did not conform to any presently recognized taxon. Comparative analyses based on 16S rRNA gene sequences confirmed the distinctiveness of the isolate, as it displayed sequence-divergence values greater than 7.7% with respect to recognized Gram-positive taxa. Phylogenetic treeing analysis served to reinforce the view that strain IMMIB L-1269(T) was distinct from recognized taxa, as it formed a relatively long subline branching within a 16S rRNA gene sequence cluster that encompassed the genera Thermoactinomyces, Laceyella, Mechercharimyces, Thermoflavimicrobium, Planifilum, Seinonella and Shimazuella of the family Thermoactinomycetaceae. On the basis of phenotypic and molecular phylogenetic evidence, strain IMMIB L-1269T represents a novel genus and species, for which the name Desmospora activa gen. nov., sp. nov. is proposed. The type strain of Desmospora activa is strain IMMIB L-1269T (=DSM 45169(T) =CCUG 55916(T)). An emencled description of the family Thermoactinomycetaceae is also given.