galE基因敲除后空肠弯曲菌变异株脂寡糖结构的改变

galE mutant of Campylobacter jejuni exhibits a changed lipooligosaccharide structure

目的 :研究galE基因敲除后空肠弯曲菌变异株脂寡糖结构改变。方法 :提取空肠弯曲菌 (CJ)HB9313及galE-变异株脂寡糖 ,Tricine SDS聚丙烯酰胺凝胶电泳分离后 ,分别进行银染、免疫印迹及霍乱毒素配体印迹检查。结果 :与野生株比较变异株的脂寡糖分子量变小 ,电泳迁移速度快 ,不能与CJHB9313脂寡糖抗体结合 ,并失去与其配体结合的能力。结论 :galE基因敲除变异株丧失了脂寡糖外核糖基及神经节苷脂CM1样结构 。

Objective:To explore if galE knock-out mutant of Campylobacter jejuni(CJ) have a changed lipooligosaccharide(LOS) structure.Methods:Lipooligosaccharide from parental strains(CJ HB9313) and mutant strains were isolated and purified.The purified LOS preparations from parental and mutant strains were resolved by Tricine SDS polyacrylamide gel electrophoresis(PAGE),analyzed by silver staining and Western blot,tested for reaction with the ganglioside-binding ligands of cholera toxin(CT).Results:Silver staining showed that the parent strain expressed a LOS molecule of around 5 5 kD,whereas the galE mutant strain expressed a molecule of 4.5 kD.The Western blot showed that the LOS,expressed by galE mutant strain,no longer reacted with antiserum raised against CJ HB9313.Compared with parent strain,the mutant lost reactivity with CT.Conclusion:These results indicate that LOS molecule of galE mutants is truncated and removes epitopes that react with antiserum and ganglioside-like structures.The absence of these structures in the galE mutants may enable the development of a safe,live-vaccine without the possibility of inducing an immune response to host gangliosides.