链霉菌702抗药性致死突变标志微波诱变筛选研究

A study on microwave induced screening of Streptomyces 702 by resistance-chemicals mutational label

目的筛选出产抗真菌活性物质的高产链霉菌702突变株。方法分别以链霉菌702菌株为试验材料和以庆大霉素为敏感抗生素建立链霉菌702孢子致死突变标志的微波诱变筛选模型,通过微波对链霉菌702菌株孢子进行不同时间的诱变处理,将诱变处理后的孢子悬液涂布于含致死浓度的庆大霉素的PDA平板培养基上,获得抗庆大霉素突变株,分别挑取单个抗药性突变菌株进行摇瓶初筛和复筛。生物效价测定采用一剂量法。结果微波处理30s对菌株的致死率可达70.53%,抗药性突变率高达23.13%,获得的抗药性突变株经过摇瓶初筛和复筛,获得高产突变株20-29-47菌株,产抗真菌活性物质的摇瓶发酵单位达到1478μg/ml,比出发菌株发酵单位986μg/ml提高了49.9%。结论采用抗药性致死突变标志的微波诱变筛选模型可以获得产抗真菌活性物质的链霉菌702高产菌株。

Objective To screen out a Streptomyces 702 strain of high yield of antifungal substance by microwave mutation. Methods Gentamicin-resistance mutational labelling selection model with Streptomyces 702 strain as experiment material and gentamicin as sensitive antibiotic was built to screening high-yield mutants. The Streptomyces 702 spores was treated by microwave in different times. Gentamicin-resistant microwave mutant is the single colony which grew on the PDA culture medium containing lethal concentration gentamicin. The single strain was choosed for primary screening and secondary screening, then determined for its yield of antifungi substance. The biological activitiy was mensurated by USP bioassays. Results The results showed that the gentamycin-resistance mutational frequency of the Streptomyces 702 treated by microwave for 30s was up to 23.13% and the lethal rate was 70.53%. High antifungal substance-producing mutant 20-29-47 was isolated in the screening experiments, and its yield of antifungal substance reached 1478μg/ml.which was 49.9% higher than that produced by its parent strain. Conclusions The Streptomyces 702 strain of high antifungal substance could be obtained by microwave mutation and resistance-chemical mutational labelling selection model.