Streptomyces sp.Tü 4128中新型抗生素bagremycins抗性基因bagJ的研究

摘要

通过框内敲除鉴定了链霉菌Streptomyces sp.Tü 4128中基因bagJ的功能.HPLC结果表明,敲除基因bagJ导致抗生素生产水平大幅降低;回补菌株恢复了抗生素的生产;过表达菌株大幅提高了抗生素的产量,证明基因bagJ在新型抗生素bagremycins的生物合成中必不可少.抑菌圈实验表明基因bagJ敲除菌株较野生菌株对bagremycins更加敏感;BagJ在Streptomyces lividans TK64中异源表达后使该菌株对bagremycins的耐受性增强,证明bagJ是新型抗生素bagremycins的抗性基因.扫描电镜的结果证明了BagJ异源表达后导致Streptomyces TK64的菌丝形态发生了改变.其他抗生素的敏感性实验表明,BagJ可能是一个逆向转运蛋白.%The function of gene bagJ via in-frame deletion in Streptomyces sp.Tü 4128 was identified.The result of HPLC analysis showed that the production of bagremycins was significantly decreased in the single knock-out strain of bagJ.The production of bagremycins was recovered in the complementation strain.The overexpression of gene bagJ resulted in producing far more bagremycins,which indicated that bagJ was indispensable in the biosynthesis of bagremycins.The test of inhibition zones showed that the bagJ mutant was more sentitive to bagremycins than the wild type.Heterogenous expression of BagJ in Streptomnyces lividans TK64 enhanced its endurance to bagremycins which suggested that bagJ might be a resistant gene of the novel antibiotics bagremycins.SEM showed that the morphology of the mycelia was changed in the heterogenous expression strain of BagJ in S.lividams TK64.The sensitivity assays of other antibiotics showed that BagJ was probably an antiporter.