伤寒沙门菌CT18和新疆XJ19体外培养条件下的蛋白质组差异分析

目的：分析我国新疆伤寒沙门菌分离株XJ19与全基因组测序的国际标准菌株CT18的蛋白表达差异,并推算基因差异。方法：运用二维蛋白电泳,对CT18和XJ19在体外培养基中的全菌蛋白进行分离,使用PDQuest软件找到其差异蛋白,进行质谱鉴定;对CT18差异蛋白编码基因设计引物,以XJ19DNA为模板进行PCR扩增,检测CT18差异蛋白编码基因在XJ19的存在情况。结果：菌株XJ19中存在53个特异蛋白点,鉴定出47个,但这些蛋白的编码基因在CT18中均存在,其中36个蛋白点在CT18的蛋白谱中不存在,11个蛋白在CT18中处于其他修饰状态;CT18中找到13个特异蛋白点,质谱鉴定出7个,其中6个所对应基因在XJ19中均能扩增出目的片段,但点C9蛋白的编码基因在XJ19中不存在。菌株XJ19中的多个差异蛋白参与磷酸戊糖途径的代谢及信号感应调控,此外超氧化物歧化酶、外膜蛋白OmpA呈现与CT18不同的修饰状态。结论：我们认为不同伤寒沙门菌分离株的遗传差异不仅仅是基因的有或无,还包括蛋白的不同表达和修饰所造成的不同调控机制和代谢的差异。

Comparative Analysis of Global Proteins of Chinese Salmonella typhi Isolate XJ19 and Sequenced Strain CT18

Objective： To reveal the global proteins and genomic difference between Salmonella typhi strain CT18 and Chinese isolate XJ19. Methods： A comparative analysis of the global proteins of S.typhi strain CT18 and Chinese isolate XJ19 was performed using two-dimensional gel electrophoresis, different proteins were found using PDQuest software and some of them were identified by mass spectrum, then PCR methodology was developed to identify the different protein coding genes of strain CT18 whether presenting in strain XJ19 or not. Results： 47 of 53 different protein spots in strain XJ19 and 6 of 7 different protein spots in strain CT18 were identified using mass spectrometry. Among different proteins of strain CT18, C9 protein coding gene presented in CT18 but not in XJ19. For strain XJ19, 36 proteins expressed in XJ19 but not in CT18, 11 proteins presented in both of the two strains with different modifications, among them all, enzymes involved in pentose phosphate pathway, global regulator LuxS, pathogenesis related factor SOD, and memberane protein OmpA had important effect in cell survival. Conclusion： The genetic differention of S.typhi isolates lies mainly in specific regulation and metabolism mechanism caused by different protein expression and modifications.