鸭疫里默氏杆菌脂多糖的结构分析与分子致病机制研究

鸭疫里默氏杆菌(Riemerella anatipestifer, RA)是一种革兰氏阴性、无芽孢、不运动的小杆菌。RA感染可引起鸭、鹅、火鸡等的高致病性、接触传染性疾病。细菌脂多糖（LPS）是革兰氏阴性菌细胞壁的主要组分之一，由类脂A，核心多糖和O-特异性多糖三部分组成。研究表明, LPS是革兰氏阴性菌的一种重要的毒力因子。目前国内外对于RA LPS的分子结构以及分子致病机制的研究仍为空白。本研究的主要内容包括：1：RA菌株CH3 （CH3） LPS的分离纯化和结构测定；2：CH3的全基因组序列测定；3：CH3 LPS合成相关基因的鉴定、突变株的构建和生物学特性测定；4：突变株对易感动物的致病性差异分析；5：突变株LPS或全菌刺激单核/巨噬细胞后细胞因子编码基因的转录及表达差异分析。6：阐明RA LPS的分子致病机制。该研究将为RA的预防和控制提供理论基础

Riemerella anatipestifer is a Gram-negative, non-spore-forming, non-motile, rod-shaped bacterium, it belongs to the genus Riemerella in the family Flavobacteriaceae. R. anatipestifer infection is a contagious disease of ducks, goose, turkeys and various other birds, and has caused the highest mortality among duck diseases. Lipopolysaccharide (LPS) is the major component of the outer membrane of Gram-negative bacteria, contributing greatly to the structural integrity and pathogenesis of the bacteria. It comprises three parts of lipid A, core oligosaccharide and O-antigen. LPS has been determined as an important virulence factor of Gram-negtive bacterium. Up to date, no structural analysis and pathogenesis study has been reported for the LPS of R. anatipestifer. This study includes:(1) Isolation and structural analysis of LPS of R. anatipestifer strain CH3. (2) Whole genome sequencing of R.anatipestifer strain CH3. (3) Determination of the genes related to the synthesis of LPS, based on the LPS structure and whole genome sequence of the strain; Construction and biological characteristics of the LPS mutants of R. anatipestifer. (4) Pathogenesis studies of the mutants on host animals. (5) Transcription and expression analysis of the genes encoding cytokine proteins on monocytes/macrophages cells stimulated with LPS or whole cell bacteria (inactivated or live). (6) Clarify the role of R. anatipestifer LPS on the molecular pathogenesis of the bacteria. This study will benefit for the future prevention and control strategies against the infection.