利用链霉素耐药性突变筛选抗菌活性放线菌

利用链霉素耐药性突变,从天然无抗菌活性或活性微弱的12株放线菌中筛选活性菌株。在链霉素浓度为25 μg/mL时共获得99株耐药菌株。通过抑菌活性测定,发现7株耐药突变菌株的发酵液产生了抑制细菌活性,其中仅耐药突变株67S-14所产生活性物质的遗传性能稳定。室内抑制真菌活性测定结果表明:菌株67S-14发酵液对玉米大斑病菌Exserohilum turcicum、番茄灰霉病菌Botrytis cinerea和棉花枯萎病菌Fusarium oxysporum f.sp.vasinfectum的抑制率较原始菌株No.67提高50%以上。该突变株在菌落形态方面与原始菌株存在较大的差异。Doskochilova溶剂系统纸层析结果表明,该活性物质可能为大环内酯类抗生素。HPLC分析结果表明,该抗生素可能是突变菌株67S-14产生的代谢产物。

Studies on the Screening of Bioactive Actinomycetes by Inducing Streptomycin Resistance Mutation

The activation experiments of twelve natural inactive actinomycetes by inducing streptomycin-resistance mutation were carried out.Ninety-nine mutants were obtained at streptomycin concentration of 25 μg/mL (MIC).Seven mutants showed bioactivity against tested bacterial were screened out,and one of them—the strain 67S-14 exhibited strong and constant inhibition effect.The results of antifungal activity in vitro showed that the inhibitory rate of fermentation broth of the strain 67S-14 was more than 50% higher than that of the wild strain No.67 against Exserohilum turcicu,Botrytis cinerea and Fusarium oxysporum f.sp.vasinfectum.The mutant 67S-14 showed obvious differences in the morphological characteristics compared with the wild-type strain No.67.The results of paper layer chromatography demonstrated that the bioactive substance might be a macrolide antibiotic.HPLC analysis showed that the antibiotic might be a metabolite of mutant 67S-14.