中文摘要：

目的：为深入研究伤寒沙门菌调节因子phoP的功能，制备伤寒沙门菌phoP基因缺陷变异株。方法：根据伤寒沙门菌phoP基因序列，设计PCR特异性引物，并在5’末端加接酶Bgl Ⅱ位点，PCR扩增phoP基因上、下游片段后，用SglⅡ消化，再定向连接成phoP基因的缺损性同源性核苷酸片段。将此片段胶回收后并导入自杀质粒pDMB151的BamHⅠ位点，将阳性质粒用电转化导入伤寒沙门菌野生株，进行同源重组。用PCR观察重组现象，将完全重组的菌株作为phoP基因的缺陷变异株，并通过相应的核苷酸序列分析加以确定。结果：PCR及序列分析证实，缺陷变异株的phoP基因缺失297个碱基。结论：成功构建伤寒沙门菌phoP基因缺陷变异株，为进一步研究其在伤寒沙门菌中的功能奠定了基础。

英文摘要：

Objective： For investigating functions of the regulator phoP of Salmonella enterica serovar Typhi, phoP gene deletion mutant of S. enterica serovar Typhi was constructed. Methods： As the genomic information, two pair＇s primers were designed at upper-and down-streams of the phoP gene of S. enterica serovar Typhi to amplify two homologous DNA fragments. A Bgl Ⅱ site was added in 5 ＇termini of the reverse primer of the upper-stream fragment and the forward primer of the down stream fragment. After amplification and purification, two fragments were digested by Bgl Ⅱ and ligated as the homologous recombinant DNA fragment, which contained the defective target gene. The homologous recombinant DNA fragment was inserted into the BamH Ⅰ site of the suicide plasmid pGMB151. The positive vector was then transferred into the target cell of S. enterica serovar Typhi wild strain by using of electroporation. The recombination was visualized by PCR, and the complete recombinant strain was selected as the phoP gene deleted mutant strain and confirmed by the corresponding sequencing analysis. Results： A deletion of 297 bp from the phoP gene was confirmed by PCR and sequencing analysis. Conclusion： The phoP gene deleted mutant of S. enterica serovar Typhi was constructed successfully, and it was a foundation to study the detail functions of phoP in S. enterica serovar Typhi.