Study on the molecular basis behind chicken colonization of Campylobacter jejuni

空肠弯曲杆菌是世界范围内食源性疾病的主要原因。本研究构建了表达绿色荧光蛋白的空肠弯曲菌，并将其口服接种2周龄雏鸡。分别于感染后0、1、4周收集盲肠内容物，通过FACS分选选择性回收GFP阳性细菌细胞。然后将收集的样品用于iTRAQ标记，从而进行LC-MS/MS分析。比较分析表明，从所有样品中一致地检测到55个蛋白质，其中3个样品在鸡接种后显示出随时间的增加而增加的蛋白质。编码3-酮酰基-(酰基-载体蛋白)还原酶的FabG突变使细胞黏附受损，但不影响细菌的运动能力，提示该突变在与宿主细胞相互作用中具有功能作用。脂肪酸组成分析表明，与亲本菌株相比，突变体中的油酸含量显著减少，这表明这种脂肪酸组成可能影响宿主与病原菌的相互作用，从而改变了这种病原菌在鸡体内的定植。

Campylobacter jejuni is a leading cause of foodborne illness worldwide. In this study, GFP-expressing C. jejuni was constructed, which was then inoculated orally to 2week-old-chicken. After 0, 1, and 4 weeks post infection, cecum contents were collected and GFP-positive bacterial cells were selectively recovered through FACS sorting. The collected samples were then used to iTRAQ-labelling, thereby being subjected to LC-MS/MS analyses. Comparative analyses revealed that 55 proteins were consistently detected from all samples, in which three samples showed increased amounts in time-dependently after chicken inoculation. Mutation of fabG that encodes putative 3-ketoacyl-(acyl-carrier-protein) reductase, impaired cell adhesion whereas did not affect bacterial motility, suggesting the functional role of this mutation in interaction to host cell. Fatty acid composition analysis revealed the significant decrease of the oleic acids in the fabG mutant, compared with the parental strain, providing an idea that such fatty acid compositions may affect host-pathogen interaction, altering intestinal colonization of this pathogen in chicken.