白蚁巢来源链霉菌T12的分离鉴定及其抗菌活性代谢产物

Isolation, identification and antimicrobial metabolites of Streptomyces sp. T12 from termite nest

摘要:

[目的] 探索黑翅土白蚁巢中链霉菌发酵产物的抗菌活性，并对其抗菌成分进行研究。[方法] 通过牛津杯法测试菌株发酵液对4种致病菌的抗菌活性，筛选出活性菌株T12；利用分子生物学16S rRNA序列分析确定T12的分类地位；运用多种色谱方法从乙酸乙酯粗提物中分离纯化活性化合物，利用质谱和核磁共振谱鉴定其化学结构；。[结果] T12被鉴定为Streptomyce sp.，当供试浓度为30 μg/滤纸片时，该菌发酵液的乙酸乙酯萃取物对金黄色葡萄球菌与白色念珠菌的抑菌效果显著，抑菌圈直径分别为20.1 mm和17.4 mm。从乙酸乙酯萃取物中分离得到2个单体化合物geldanamycin （1）和17-O-demethylgeldanamycin （2）。抗菌活性测试表明，在供试浓度30 μg/滤纸片时，化合物1和2表现出很好的抑菌活性，对金黄色葡萄球菌的抑制圈直径分别为14.6 mm和14.5 mm，与阳性对照硫酸庆大霉素的活性相当，对白色念珠菌的抑制圈直径分别为10.9 mm和13.9 mm，与阳性对照两性霉素的活性相当。[结论] 菌株T12具有开发为新型微生物源杀菌剂的应用价值。

Abstract:

[Objective] To investigate antimicrobial activity and metabolites of Streptomyces sp. from the termite nest. [Methods] Antimicrobial activities of fermentation broth against four pathogenic microbes were tested by Oxford cup method. The bioactive strain T12 was identified by molecular biology 16S rRNA sequence analysis. The active metabolites of T12 were isolated and purified from ethyl acetate crude extracts by various chromatographic methods, and their chemical structures were identified by mass spectrometry and nuclear magnetic resonance spectroscopy, and their antimicrobial activities were determined by filter paper method.[Results] T12 was identified as Streptomyces sp.. Under the concentration of 30 μg/filter paper, the ethyl acetate extract of T12 had potent antibacterial activities against Staphylococcus aureus and Candida albicans with inhibition zone diameters of 20.1 mm and 17.4 mm, respectively. Two metabolites including geldanamycin (1) and 17-O-demethylgeldanamycin (2), were isolated and characterized from fermentation broth. Both metabolites 1 and 2 exhibited good antimicrobial activity at the concentration of 30 μg/filter paper. The inhibition diameters of compounds 1 and 2 against S. aureus were 14.6 mm and 14.5 mm respectively, which were equivalent to those of gentamicin sulfate as positive control. The inhibition diameters of compounds 1 and 2 against C. albicans were 10.9 mm and 13.9 mm respectively, which were comparable to those of the referenced amphotericin. [Conclusion] Strain T12 could be potentially developed as a new microbial microbicide.