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

 描述(申请人提供)：直肠弯曲杆菌是一种杆状革兰氏阴性厌氧口腔细菌，已在90%的成年人初期或已确诊的牙周炎中被鉴定出来，相比之下，健康人群中只有10%，牙龈炎患者中只有20%。除了与牙周疾病明显相关外，最近的研究还强调了直肠弯曲菌感染与Barrett‘s esopagus、口腔和口腔外脓肿、炎症性肠道疾病以及人类不良妊娠结局(包括早产和低出生体重)的关系。尽管直肠弯曲杆菌经常从人类中分离出来，但人们对此知之甚少 关于与这种新出现的病原体相关的发病机制的分子机制。为了开始对直肠弯曲菌致病机理的分析，我们将研究空肠弯曲菌致病过程中涉及的侵袭和侵袭相关基因是否也与直肠弯曲菌的致病机制有关。特别是，我们将1)确定标记为CIAB[弯曲菌入侵抗原B]的直肠弯曲菌基因是否为空肠弯曲菌CIAB的功能同源物；2)确定直肠弯曲菌CIAB的分泌状态，从而确定直肠弯曲菌是否存在功能性鞭毛II型分泌系统。从这个小项目中获得的结果将支持未来更大规模的直肠肌功能基因组研究，以了解直肠肌是如何导致人类疾病的。

 DESCRIPTION (provided by applicant): 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 II 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.