球孢链霉菌JK-1抗菌物质的理化特性研究

目的]明确球孢链霉菌JK-1抗菌物质的基本理化性质.方法]以稻瘟菌为指示菌,采用菌丝生长速率法分别测定球孢链霉菌JK-1发酵滤液在不同温度、不同酸碱度、蛋白酶K处理和硫酸铵盐析之后的抑菌活性;采用硫酸铵盐析对抗菌物质进行初步提纯,并通过超滤的方法初步测定该抗菌物质的分子量大小.结果]球孢链霉菌JK-1产生的抗菌物质在高温和蛋白酶K处理的情况下抑菌活性显著降低,在pH2 ～ 11条件下抑菌活性无显著变化,而pH≥11的强碱性条件下抑菌活性显著降低.饱和度为50％的硫酸铵即可将发酵液中的抗菌物质完全沉淀下来,超滤发现其分子量在10 ～ 30 kD.结论]该研究结果为球孢链霉菌的田间应用及其抗菌物质的分离鉴定奠定了基础.

Study on Physicochemical Property of Antifungal Substances from Streptomyces globisporus JK-1

Objective] The aim was to understand basical physicochemical property of antifungal substances from S.globisporus JK-1.Method] Antifungal activity against Magnaporthe oryzae was determined after the culture filtrates of S.globisporus JK-1 were treated in various temperatures,pH values,proteinase K or ammonium sulfate precipitation,using the mycelial growth rate method.The antifungal substances were purified priliminarily by ammonium sulfate precipitation,and the range of molecular weight of the antifungal substance was determined with ultrafiltration.Result] The antifungal activity was significantly lower than control after being treated with high temperature,strong alkalinity （pH ≥ 11） or proteinase K.However,no significant difference was observed when it was treated at the pH ranging from 2 to 11.Ammoniun sulfate precipitation could be used to purify the antifungal substances preliminarily,and the molecular weight of the antifungal substance was between 10 kD and 30 kD.Conclusion] The study result provide a basic for field application and further isolation,purification and identification of the antifungal substances.