白蚁链霉菌(Streptomyces termitum)ACT-2菌株拮抗物质的分离纯化、解析及活性分析

Solation,Purification,Analysis,Bioactivities Analysis of Antagonistic Substance in Streptomyces termitum Strain ACT-2

从浙江省金华市郊水稻田土壤中筛到1株拮抗水稻白叶枯病菌的白蚁链霉菌(Streptomyces termitum)ACT-2菌株。该菌株的菌体和发酵液对水稻白叶枯病菌均表现出较强的拮抗能力;水稻盆栽生防试验结果表明:对水稻白叶枯病有较好的防效,生防效果最高可达80.80%。通过分步萃取、硅胶柱层析、凝胶柱层析等步骤,分离纯化获得拮抗活性物质,对目标物进行核磁共振氢谱分析和质谱分析,通过解析与比对该目标物为Aloesaponarin II(1-甲基-3,8-二羟基蒽醌),分子式为C15H10O4。以氯霉素为对照,测定纯化的Aloesaponarin II对水稻白叶枯病菌拮抗活性,结果表明Aloesaponarin II具有较强的抗菌活性,半抑制浓度为IC50=19.2μg/mL,但较氯霉素弱(半抑制浓度为IC50=0.39μg/mL)。

A Streptomyces termitum strain ACT-2 with antimicrobial activity against paddy white leaf wilt（ Xan-thomonas oryzae pv. oryzae）（Xoo）race P6 was screened from rice field soil in the suburb of Jinhua. Thalamus of strain ACT-2 and its fermentation both possessed with fairly strong antimicrobial activity to Xoo race P6. The best bio-control effects of the fermentation broth of strain ACT-2 on Xoo in experiments in pot cultivated paddy reached as high as 80. 80% . In this study,step-by-step extraction,silica gel column chromatography,gel column chromatography, and other steps,and obtained an antagonistic active substance by isolation and purification. Structural determination was made by 1 H NMR and EI-MS analyses. The targeted substance was Aloesaponarin II（1-methyl-3,8-dihydroxyl-anthraquinone）,with the molecular formula C15 H10 O4 by analyses and comparison. The antimicrobial activity of puri-fied Aloesaponarin II against Xoo race P6 was tested taking chloromycetin as a control. The results showed that Aloe-saponarin II possessed fairly strong antibiotic activity,its semi-inhibition concentration was IC50 = 19. 2 μg/ mL,but weaker than that of chloromycetin（IC50 = 0. 39 μg/ mL）.