The importance of host cell invasion and type III secretion to Campylobacter rectus virulence

项目摘要 直肠弯曲杆菌是一种杆状革兰氏阴性厌氧口腔细菌，已鉴定出90% 在患有初始或已确诊牙周炎的成年人中，这一比例为10%，而在健康人群中为20% 患有牙周炎的人。除了与牙周病有明确的联系外，最近的研究还 强调直肠弯曲菌感染与Barrett氏内翻、口腔和口外脓肿有关， 人类炎症性肠病和不良妊娠结局，包括早产和低产 体重。尽管直肠弯曲杆菌经常从人类中分离出来，但对其分子机制知之甚少。 与这种新出现的病原体相关的发病机制。为了开始对直肠弯曲菌的分析 发病机制，我们将调查侵袭和侵袭相关基因是否参与弯曲杆菌 空肠致病也是直肠弯曲菌致病的原因。特别是，我们将1)确定C. 直肠弯曲菌基因CIAB是空肠弯曲菌CIAB的功能同源物； 确定CIAB的分泌状态，从而确定一种功能性鞭毛III型 直肠肌存在分泌系统。从这个小项目中获得的结果将支持未来的功能 更大规模的直肠弯曲菌基因组研究，以了解直肠弯曲菌在人类疾病中的作用。

Project Summary Campylobacter rectus is a rod-shaped Gram-negative anaerobic oral bacterium that has been identified in 90% of adults with initial or established periodontitis, compared with 10% of healthy individuals and 20% of individuals with gingivitis. In addition to a clear association with periodontal disease, recent studies have highlighted the involvement of C. rectus infection in Barrett's esophoagus, oral and extraoral abcesses, inflammatory bowel disease and adverse pregnancy outcomes in humans including pre-term birth and low birth weight. Despite the frequent isolation of C. rectus from humans little is known about the molecular mechanisms of pathogenesis associated with this emerging pathogen. In order to begin an analysis of C. rectus pathogenesis, we will investigate whether invasion and invasion-related genes involved in Campylobacter jejuni pathogenesis are also responsible for C. rectus pathogenesis. In particular, we will 1) Determine if the C. rectus gene annotated as ciaB [Campylobacter invasion antigen B] is a functional homolog to C. jejuni ciaB; 2) Determine the secretion status of C. rectus ciaB and thereby establish whether a functional flagellar type III secretion system exists in C. rectus. Results gained from this small project will support future functional genomic studies of C. rectus on a larger scale to understand how C. rectus contributes to human disease.