腺嘌呤对大肠杆菌DH5α及其耐乙酸突变株DA19生长和代谢的影响

Effects of adenine on the growth and metabolism of Escherichia coli DH5α and its acetate-tolerant mutant DA19

摘要:

大肠杆菌DH5α和DA19在碳源限制的基本培养基中进行分批培养和氮源限制的基本培养基中进行连续培养,发现添加腺嘌呤会使DH5α生长改善,乙酸产生减少;对DA19的生长和代谢影响不明显。连续培养细胞的蛋白质组分析结果显示:添加腺嘌呤后DA19 purH表达水平降低,而DH5α purH表达水平不变,表明DH5α嘌呤核苷酸从头合成能力差;DH5α yddS表达上调,gnd表达水平稍有提高,细胞生长改善。

Abstract:

Batch cultures of Escherichia coli DH5α and DA19 in carbon source limited defined media and continuous cultures in nitrogen source limited defined media were performed to compare the metabolism in both strains. DH5α showed improved growth and less acetic acid production after supplementation of adenine, but adenine had little effects on the metabolism of DA19. The proteomic analysis showed that expression of purH was down regulated in DA19 by addition of adenine while was unchanged in DH5α, suggesting that the de novo synthesis ability of purine nucleotide in DH5α was poorer than that in DA19. Supplementation of adenine resulted in enhanced expression of gnd and yddS in DH5α, and thus improved the growth.