无机盐对阿维链霉菌接合转移及异源表达放线紫红素的影响

Effect of inorganic salts on the conjugation and heterologous expression of actinorhodin in Streptomyces avermitilis

摘要:

摘要：【目的】阿维链霉菌可作为异源表达抗生素生物合成基因簇的良好宿主，但是需要优化含有大片段DNA质粒的接合转移效率。【方法】我们选取MgCl2、NaCl、Ca(NO3)2 和CaCl2等4种无机盐，在0－200 mmol/L浓度范围内分别研究其对大质粒向阿维链霉菌接合转移的影响，再设计完全随机试验筛选最佳条件。【结果】CaCl2对阿维链霉菌接合转移有极明显的促进作用，MgCl2也有一定提高作用。通过完全随机试验筛选出最佳的CaCl2和MgCl2浓度组合，使大质粒的接合转移效率提高11倍。同时，本研究还发现阿维链霉菌异源表达放线紫红素的最适培养基，成功表达放线紫红素。【结论】特定无机盐对阿维链霉菌接合转移效率有明显提高作用，并且能促进放线紫红素在阿维链霉菌中的表达。

Abstract:

Abstract: [Objective] Streptomyces avermitilis NRRL8165 could serve as a good host for heterlogous expression of antibiotics biosynthetic gene clusters. However, it needs to improve its conjugation frequency to accept large plasmids. [Methods] We chose MgCl2 , NaCl, Ca(NO3)2 and CaCl2, to test whether they affected the conjugation frequency of large plasmids at salt concentration from 0-200 mmol/L. A complete random experiment was designed for optimization. [Results] We found that CaCl2 promoted conjugation dramatically, and MgCl2 did significantly too. The complete random experiment led to diclosure of an optimal combination of MgCl2 and CaCl2 by which the conjugation frequency was improved by 11 fold. In addition, a supplemented medium was found to lead to successful heterologous expression of actinorhodin in S. avermitilis. [Conclusion] Some inorganic salts can not only significantly improve the conjugation frequency of Streptomyces avermitilis NRRL8165 but also promote the expression of actinorhodin in Streptomyces avermitilis NRRL8165.