Study on the Reclassification of Two Deposited Strains AS4. 1186 and AS4. 1187 of Nocardia
对诺卡氏菌AS4.1186和AS4.1187保藏菌株的重新分类研究

Polyphasic evidence for the reclassification of Nocardia nostocoides AS4.1186 and Nocardia salmonicolor var. aurantiaca AS4.1187 indicated that strain AS4.1186 was closely related to Saccharothrix texasensis and strain AS4.1187 was very closely related to Rhodococcus ruber. Binary 16S rDNA sequence for the pair AS4.1186 and Saccharothrix texasensis NRRL B-16134 T, and the pair AS4.1187 and Rhodococcus ruber DSM 43338 T exhibited 99.3% and 99.5% similarity, respectively. Corresponding DNA-DNA reassociation values were significantly higher than 70%, 77.6% and 82.9%, respectively. Results of chemotaxonomic analyses of cell wall, mycolic acid, principal menaquinones, phospholipid type and the G+C content of the DNA supported the conclusions of the genotypic analyses. The very similar morphological and physiological characteristics agreed with the high degree of relatedness. On the basis of phylogenetic analyses, DNA-DNA reassociation values, chemotaxonomic properties, morphological and physiological characteristics, it is concluded that strain AS4.1186 and AS4.1187 should be removed from the genus Nocardia. We propose to transfer Nocardia nostocoides AS4.1186 to the genus Saccharothrix, combine with the species S.texasensis, and combine Nocardia salmonicolor var. aurantiaca AS4.1187 with the species Rhodococcus ruber.