具抗肿瘤活性放线菌菌株YIM 90022的分离和系统发育分析

Isolation and phylogenetic analysis of one actinomycete strain YIM 90022 exhibiting anticancer activity

从青海盐碱土壤样品中分离到一株兼性嗜碱放线菌YIM 90022，该菌株的发酵产物具有很强的体外抗胃癌、肺癌、乳腺癌、皮肤癌、肾癌和子宫癌肿瘤细胞株活性。基于16S rRNA基因序列的系统发育分析表明，菌株YIM 90022属于拟诺卡氏属（Nocardiopsis）的成员，与该属的4个有效发表种N．exhalans DSM 44407^T，N．prasina DSM 43845^T，N．metallicus DSM 44598^T和N．listeri DSM 40297^T系统发育关系最密切，与其分别以98．8％，98．5％，98．4％和97．8％的16S rRNA基因核苷酸序列相似性聚为一簇。但菌株YIM 90022不与这4个有效种中任何一个单独相聚，形成了一个独立亚分枝。结合形态特征、生理生化特性、细胞化学分类特征，以及rep-PCR基因指纹分析等方面的研究结果，菌株YIM 90022可能为拟诺卡氏菌属的一个潜在新种。菌株YIM 90022在大多数培养基上生长良好，气生菌丝和基内菌丝丰富，在酵母膏麦芽膏琼脂、燕麦片琼脂等培养基中产生可溶性色素。生长pH范围6．0．12．0，最适pH8．5；能在含0—15％NaCl（W／V）的培养基上生长。

One facultative alkaliphilic actinomycete strain YIM 90022 was isolated from hypersaline alkaline soil in Qinghai province, China. An almost-complete 16S rRNA gene sequence （1500 bp） for strain YIM 90022 was obtained Phylogenetic analysis based on 16S rRNA gene sequences showed that strain YIM 90022 was closely related to four members of the genus Nocardiopsis with 16S rRNA gene sequence similarity values of 98.8 % （ N. exhalans DSM 44407^T）, 98.5% （N.prasina DSM 43845^T）, 98.4% （N. metallicus DSM 44598^T） and 97.8% （N. listeri DSM 40297^T）, but represented a distinct phylogenetic lineage. Repetitive element sequence-based PCR （rep-PCR） genomic fingerprinting was evaluated on strain YIM 90022 and its closest relatives to investigate their genetic relatedness. The analysis of the rep-PCR genomic fingerprints showed that strain YIM 90022 was distinguishable from its closest relatives. The polyphasic taxonomic data presented in this study, including its morphology, physiological and biochemical characteristics, chemotaxonomy, 16S rRNA gene sequence-based phylogenetic analysis and rep-PCR genomic fingerprinting, supported the view that strain YIM 90022 represented a potential new species of the genus Nocardiopsis. The fermentation broth of strain YIM 90022 strongly inhibited growth of cell series of gastric cancer, lung cancer, mammary cancer, melanoma cancer, renal cancer and uterus cancer. Strain YIM 90022 grew well on most tested media, producing exuberant vegetative hyphae and aerial hyphae. The vegetative hyphae are long and fragmented. Light yellow to deep brown diffusible pigments were produced on ISP 2, ISP 3 and ISP 6. Growth of the strain occurred in the pH range 6.0- 12.0, with optimal pH 8.5. The NaCl tolerate range was 0- 15 % （W/V）. Cell walls contain mesodiaminopimelic acid and have no diagnostic sugars. Polar lipids are phosphatidylcholine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylmethylethanolamine. Major menaquinones are MK-10（H4, H6）. The DNA G ＋ C content is 71.5 mol %.