对诺卡氏菌AS4.1186和AS4.1187保藏菌株的重新分类研究

Study on the Reclassification of Two Deposited Strains AS4.1186 and AS4.1187 of Nocardia

重新对念球状诺卡氏菌 (Nocardianostocoides)AS4 1 1 86和鲑色诺卡氏菌桔橙变种(Nocardiasalmonicolorvar.aurantiaca)AS4 1 1 87进行的多相分类研究表明 ,菌株AS4 1 1 86与德克萨斯糖丝菌 (Saccharothrixtexasensis)NRRLB 1 6 1 3 4 T 关系密切 ,它们的 1 6SrDNA序列相似性为 99 3 % ,DNA同源性为 77 6 % ;菌株AS4 1 1 87与赤红球菌 (Rhodococcusruber)DSM 43 3 3 8T 之间有着密切的关系 ,其 1 6SrDNA序列相似性为 99 5 % ,DNA同源性为 82 9%。胞壁组分、枝菌酸、甲基萘醌、磷酸类脂和DNAG +Cmol%测定等化学分类结果支持了上述结论。在形态和生理生化特性上 ,菌株AS4 1 1 86与NRRLB 1 6 1 3 4 T,菌株AS4 1 1 87与DSM 43 3 3 8T 之间也表现出非常相似的性状。根据系统发育分析、DNA同源性值、化学分类、形态和生理生化特性等研究结果 ,我们对菌株AS4 1 1 86和AS4 1 1 87的分类地位做了修正 ,将其从诺卡氏菌属中排除 ,认为念球状诺卡氏菌 (Nocardianostocoides)AS4 1 1 86与Saccharothrixtexasensis是同一个种 ,建议合并为Saccharothrixtexasensis;鲑色诺卡氏菌桔橙变种 (Nocardiasalmonicolorvar.aurantia ca)AS4 1 1 87与Rhodococcusruber是相同种 。

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.