枯草芽孢杆菌胞外氨肽酶对菌体生长的作用研究

【目的】利用基因敲除技术构建突变菌株BS-AP-K来研究枯草芽孢杆菌的分泌型氨肽酶对菌体生长的作用。【方法】基于Xer/dif重组系统敲除Bacillus subtilis 168基因组中ywaD基因，研究比较野生型与BS-AP-K菌株在不同培养基中的生长情况。【结果】通过比较两菌株的生长情况，发现敲除分泌型氨肽酶会对菌体生长带来不利影响，而这种影响可以通过在培养基中添加多种游离氨基酸来弥补。【结论】研究结果表明胞外氨肽酶通过酶切外源蛋白质以及多肽来为细胞生长提供营养所需。

Effect of secretory aminopeptidase in Bacillus subtilis on the growth

Objective] Aim to study the effect of secretory aminopeptidase in Bacillus subtilis 168 on the growth, a gene knock-out mutant BS-AP-K was constructed. Methods] Based on the Xer/dif recombinant system, the ywaD gene was deleted from the genome. The growth of wild type and BS-AP-K in different media was monitored. Results] It turned out that the deletion of secretory aminopeptidase had a negative effect on the growth of the strain. The impaired growth rate of BS-AP-K strain can be overcome by amino acid supplements. Conclusion] This study indicated that the secretory aminopeptidase played an important role in supplying amino acids required for growth by hydrolyzing proteins or peptides.