酪蛋白水解物对雷帕霉素产生菌Streptomyces hygroscopicus ATCC29253 接合转移效率的影响

Effect of casamino acid on intergeneric conjugation in rapamycin-producing Streptomyces hygroscopicus ATCC29253

摘要:

摘要:吸水链霉菌(Streptomyces hygroscopicus)ATCC29253 能够产生非常丰富的次级代谢产物，除了雷帕霉素外，还可以分泌尼日利亚菌素、洋橄榄叶素、六烯类抗生素等多种具有生物活性的物质，具有重要的研究价值和应用前景。【目的】而建立高效的遗传操作系统是研究该链霉菌相关代谢产物合成机理和构建基因工程菌株的基础。【方法】我们测试了不同培养基及供体菌对吸水链霉菌及其它链霉菌接合转移效率的影响。【结果】我们发现酪蛋白水解物和镁离子能显著提高S.hygroscopicus ATCC29253 接合转移效率。通过随机组合试验，筛选出最佳的MgCl2和酪蛋白水解物浓度组合，使得S． hygroscopicus ATCC29253 接合转移效率达到1.5×10－4。同时我们还发现酪蛋白水解物可以明显改变S.lividans、S.albus、S.avermitilis 的接合转移效率。【结论】本研究首次发现酪蛋白水解物不光对S.hygroscopicus ATCC29253 接合转移有作用，对其它常用的链霉菌如S.lividans、S.albus、S.avermitilis 等的接合转移效率都有显著的影响。

Abstract:

Abstract:［Objective］Streptomyces hygroscopicus ATCC29253 has attracted much interests due to its capacity of producing various secondary metabolites with strong bioactivities，including immunosuppressant rapamycin，nigericin，hexaenes，elaiophylin and hygrocins． ［Objective］To investigate biosynthetic pathway of these metabolites and construct high-yield strains by genetic engineering，establishment of a highly efficient genetic manipulation system is critically required in this strain． ［Methods］We tested the effects of conjugation media and donor strains on conjugal transfer from Escherichia coli to S． hygroscopicus ATCC29253 and other Streptomycetes． ［Results］ We found that both casamino acid and MgCl2 supplemented in conjugation media improved conjugation frequency in S． hygroscopicus ATCC29253. A random experiment led to the disclosure of an optimal combination of casamino acid and MgCl2 by which the conjugation frequency in S． hygroscopicus reached 1. 5 × 10 － 4 ． Meanwhile，we also found significant changes in conjugation frequencies of S．lividans，S． albus and S． avermitilis when casamino acid was supplemented in conjugation media． ［Conclusion］Casamino acid has significant influence on conjugation frequency in not only S． hygroscopicus ATCC29253 but also other Streptomyces such as S． lividans，S． albus and S． avermitilis．