红树林来源白浅灰链霉菌中生物碱类次级代谢产物研究及核糖体工程优化

综合应用Sephadex LH-20柱层析、反相中压液相柱层析、正相硅胶柱层析等方法对白浅灰链霉菌(Streptomyces albogriseolus)MGR072的生物碱类次级代谢产物的化学成分进行色谱分离,并运用紫外吸收、核磁及质谱等波谱方法对结构进行解析和鉴定,确定了两个化合物结构,分别为2-喹啉酸酯和4(1H)喹唑酮;基于核糖体工程原理,对该野生型菌株进行抗链霉素和抗利福霉素突变株筛选,得到1765株抗性突变株,其中S1、S2、S3、S4、R1、R2这6株的目标产物产量发生不同程度的变化,突变株R1、S3、S4相应峰的积分面积高达野生型菌株(WT)的15、24和12倍;突变株R2的相应峰几乎中断消失.本研究显示针对红树林微生物中丰富的生物碱类次级代谢产物,可通过定向化学分离和核糖体工程优化,快速锁定其中微量的新颖结构类群并对其产量进行调控,为后续分离新天然产物打下基础.

Research on the alkaloids produced by a mangrove Streptomyces albogriseolus and modulation of secondary metabolites by ribosome engineering

Streptornyces albogriseolus MGR072 was isolated from the sediments collected in Zhangjiangkou Mangrove Natural Reserve, Fujian province. The strain was cultivated in ISP3 medium and the fermentation broth was extracted by organic solvent. Alkaloids in the fiactionated extractions were tracked by dragendorff reagent and separated by chromatographic method. 2Quinolinecarboxylic acid （ 1 ） and 4 （ l H） Quinazolinone （ 2 ） were identified by NMR and MS. A collection of 1765 spontaneous streptomycin and rifampicin resistant mutants were developed to stimulate secondaly metabolism in the strain, guided by special UV absorptions of 1 and 2. The differences in the HPLC fingerprints of the wildtype and the mutant strains （ S1,S2, S3, S4, R1, R2） showed the changing of metabolic profiles ribosome engineering. The increased accumulation of secondary metabolites in 3 mutant strains, e. g. S3, RI and S4, was observed. This study suggested that the profile of the secondary metabolites fi＇om the mangrove microbes could be regulated by ribosome engineering. It is possible to trace and purify novel nature products from the engineered strains by directed chemical separation.