利用平板分离法从家蝇中分离出14株家蝇共生真菌，活性筛选表明CY-03有较好的抗菌活性，在供试浓度为0.1 mg/mL时，CY-03发酵液乙酸乙酯萃取物对番茄早疫病菌和苹果树腐烂病菌具有较好的抑制作用，抑制率约60%；在供试浓度为30μg/滤纸片时，与阳性对照相比，乙酸乙酯提取物对枯草芽胞杆菌有中等的抑制作用，抑菌圈直径为21.0 mm。进一步研究CY-03发酵液不同极性溶剂萃取物的抗菌活性，结果表明其活性物质主要集中在中等极性部位，在供试浓度为0.1 mg/mL时，CY-03发酵液乙酸乙酯提取物对苹果树腐烂病菌、杨树溃疡病菌、番茄早疫病菌和苦瓜枯萎病菌等具有较好的抑制作用，抑制率均大于45%；在供试浓度为30μg/滤纸片时，乙酸乙酯提取物对金黄色葡萄球菌、枯草杆菌和大肠埃希菌有中等的抑制作用，抑菌圈直径范围为14.8~23.0 mm。通过形态学特征观察和5.8S rDNA测序分析，初步确定该菌株为尖孢镰刀菌（ Fusarium oxysporum）。CY-03作为微生物源杀菌剂值得进一步研究。%Fourteen housefly symbiotic fungi were isolated from the gut of housefly by means of spread plate isolation method. Screening of activity showed that strain CY-03 showed better antimicrobial activity,under tested concentration at 0. 1 mg/mL,the acetic acetate extract( AAE)of CY-03 fermented broth had preferable antifungal activity against pathogens of tomato early blight,apple canker with inhibition rate at 60%;when the tested concentration was at 30μg/filter paper,as compared with positive control,AAE had medium inhibition against B. subtilis with inhibition ring at 21. 0 mm. The antimicrobial activity of CY-03 fermented broth extracted with different polar solvent was further studied,the results showed that the active substances were focused on the parts of medium polarity,when the tested concentraion was at 0. 1 mg/mL,the AAE of CY-03 fermented broth had better inhibition against the pathogens of poplar ulcer,tomato early blight,and balsam pear firing with inhibition rate of over 45%;when the tested concentra-tion was at 30μg/filter paper,the AAE had medium inhibition against Streptococcus aureus,Bacillus substilis,and E. coli,with inhibition rings ranged at 14. 8~23. 0 mm. The strain was initially identified as Fusarium oxysporum mor-phologically and through 5. 8S rDNA sequence analysis. CY-03 is worthy to study further as antimicrobial preparation of microbial resources.
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