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目的筛选来自塔克拉玛干沙漠沙生植物对铜绿假单胞菌具有抑制活性的内生放线菌菌株,对拟诺卡菌属菌株38-7L-1发酵液中活性化合物进行分析预测、分离纯化和结构验证。方法采用琼脂平板法进行抗菌活性筛选;基于16S r RNA基因序列对菌株38-7L-1进行初步分类鉴定;基于菌株38-7L-1 PKS I基因的KS域序列分析结果 ,结合活性峰的液-质联用数据,比对微生物天然产物数据库,预测活性化合物201的结构;通过色谱方法纯化化合物201;结合光谱数据分析及文献比对,确定和验证化合物201的结构。结果从81株沙生植物内生放线菌中获得7株活性菌株,包括链霉菌属菌株4株、考克菌属菌株1株、多形孢菌属菌株1株和拟诺卡菌属菌株1株。其中菌株38-7L-1活性最强并具有I型聚酮合酶基因,16S r RNA基因序列分析表明该菌株与Nocardiopsis alba DSM 43377T(X97883)的相似率为100%。菌株3 8-7L-1抗铜绿假单胞菌活性次级代谢产物,化合物201为十六元大环内酯类化合物,蔷薇霉素。结论 首次从拟诺卡菌中分离到常见于小单孢菌的蔷薇霉素,多策略组合对次级代谢产物结构预测具有指导意义。
Objective To screen endophytic actinomycetes strains of inhibitory activities against P. aeruginosa from sandy desert plants in Taklamakan Desert and to analyze and predict the active compounds in the fermentation broth of pseudomonas sp. Strain 38-7L-1. Purification and structure verification. Methods The antibacterial activity was determined by agar plate method. Based on the 16S rRNA gene sequence, the strain 38-7L-1 was preliminarily identified and identified. Based on the KS domain sequence analysis of the PKS I gene of strain 38-7L-1, - Mass spectrometry data, comparing the natural product database of microorganism to predict the structure of the active compound 201; Purifying the compound 201 by the chromatographic method; Identifying and verifying the structure of the compound 201 by combining spectral data analysis and literature comparison. RESULTS: Seven strains of Streptomyces endophyticus were obtained from 81 strains of endophytic actinomycetes, including 4 strains of Streptomyces, 1 strain of Coccus, 1 strain of Polymorphis and 1 strain of Nocardia 1 strain. Among them, strain 38-7L-1 was the most active and had type I polyketide synthase gene. Sequence analysis of 16S rRNA gene showed that the similarity of this strain to Nocardiopsis alba DSM 43377T (X97883) was 100%. Strain 38-7L-1 is an active secondary metabolite against Pseudomonas aeruginosa, and compound 201 is a 16-membered macrolide compound, Romycin. Conclusion For the first time, Romycin, which is commonly found in Micrococcus species, has been isolated from Nocardiopsis. The multi-strategy combination is instructive in predicting the structure of secondary metabolites.