Abstract
A Gram-staining-positive, filamentous bacterial strain, designated A-T 0308(T), was isolated from soil of a tropical mangrove forest in Thailand. Strain A-T 0308T developed spherical sporangia containing non-motile spores on aerial mycelium. The novel strain contained meso-diaminopimelic acid, N-acetyl-type peptidoglycan and madurose, mannose, ribose, galactose and glucose as whole-cell sugars. The predominant menaquinones were MK-9(H(4)) and MK-9(H(6)); a small amount of MK-9(H(2)) and MK-9 was also detected. Mycolic acids were not detected. The diagnostic phospholipids were phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylinositol, phosphatidylinositol mannoside and phosphoglycolipid. The predominant cellular fatty acids were iso-C(16:0) and 10-methylated C(17:0). The G+C content of the DNA was 72 mol%. Phenotypic and chemotaxonomic analyses showed that the novel isolate had characteristics typical of members of the genus Sphaerisporangium. 16S rRNA gene sequence analysis also indicated that the strain belongs to the genus Sphaerisporangium and that it represents a clade distinct from other members of the genus with sequence similarities ranging from 96.3 to 97.80/0 between the novel strain and its closest relatives. Based on the results of phenotypic, chemotaxonomic and phylogenetic studies, strain A-T 0308(T) (=BCC 21702(T) =NBRC 107571(T)) represents a novel species of the genus Sphaerisporangium, for which the name Sphaerisporangium krabiense sp. nov. is proposed.
