空肠弯曲菌fliD基因突变株的构建及其生物学特性

Construction and characterization of a Campylobacter jejuni fliD mutant

【目的】研究fliD基因对空肠弯曲菌生物学特性的影响,为阐明该基因的功能和作用机制奠定基础。【方法】利用同源重组技术构建fliD基因的插入失活突变株NCTC11168△fliD,并通过与野生株比较,对fliD突变株生长速率、运动力、黏附力和侵袭力等生物学特性进行研究。【结果】与野生型NCTC11168相比,突变株NCTC11168△fliD的生理生化特性不变;突变株的生长速率无明显变化;MH半固体穿刺实验中,突变株只能在接种处生长,运动力明显减弱;在Caco-2细胞黏附、侵袭实验中,fliD突变株的黏附率和侵袭率分别为164.00±19.49、55.00±6.09,fliD基因失活使得突变株的黏附率和侵袭率显著降低(0<P<0.01)。【结论】fliD基因是空肠弯曲菌运动能力重要的分子基础,与空肠弯曲菌感染细胞的黏附侵袭作用密切相关,即与空肠弯曲菌的致病性密切相关。

[Objective] We studied the biological characteristics of thefliD mutant strain to clarify the function and mechanism of fliD gene. [Methods] The fliD mutant was constructed through homologous recombination, and biological characteristics of the fliD mutant were identified in comparison with the wild type of Campylobacter jejuni. [Results] Mutant NCTC11168△fliD presented the same biochemical indexes and similar growth curves of the wild type. After being inoculated into semisolid Mueller Hinton ager plate, the wild strain presented diffusion growth phenotype, but fliD mutant could only grow in the site inoculated, indicating that its motility was significantly reduced. The adhesion rate and invasion rate offliD mutant were 164.00±19.49 and 55.00：t：6.09 respectively, which means that the mutation offliD gene significantly reduced the rates of adhesion and invasion. [Conclusion] fliD gene was not only an important molecular basis for bacterial motility but also necessary for the adhesion and invasion of Campylobacterjejuni infection cells.