Description of gamma radiation-resistant Geodermatophilus dictyosporus sp. nov. to accommodate the not validly named Geodermatophilus obscurus subsp. dictyosporus (Luedemann, 1968).

Abstract

A gamma radiation-resistant, Gram reaction-positive, aerobic and chemoorganotrophic actinobacterium, initially designated Geodermatophilus obscurus subsp. dictyosporus G-5(T), was not validly named at the time of initial publication (1968). G-5(T) formed black-colored colonies on GYM agar. The optimal growth range was 25-35 °C, at pH 6.5-9.5 and in the absence of NaCl. Chemotaxonomic and molecular characteristics of the isolate matched those described for members of the genus Geodermatophilus. The DNA G + C content of the strain was 75.3 mol%. The peptidoglycan contained meso-diaminopimelic acid as diagnostic diamino acid. The main polar lipids were phosphatidylcholine, diphosphatidylglycerol, phosphatidylinositol, phosphatidylethanolamine and one unspecified glycolipid; MK-9(H4) was the dominant menaquinone and galactose was detected as a diagnostic sugar. The major cellular fatty acids were branched-chain saturated acids, iso-C16:0 and iso-C15:0. The 16S rRNA gene showed 94.8-98.4 % sequence identity with the members of the genus Geodermatophilus. Based on phenotypic results and 16S rRNA gene sequence analysis, strain G-5(T) is proposed to represent a novel species, Geodermatophilus dictyosporus and the type strain is G-5(T) (=DSM 43161(T) = CCUG 62970(T) = MTCC 11558(T) = ATCC 25080(T) = CBS 234.69(T) = IFO 13317(T) = KCC A-0154(T) = NBRC 13317(T)). The INSDC accession number is HF970584.