OmpT对禽致病性大肠杆菌生物学特性和致病性影响的研究  

Effects of OmpT on biological characteristics and pathogenicity of avian pathogenic Escherichia coil

作　　者：宋祥军 蒋胡艳 侯曼曼 涂健[1] 邵颖[1] 刘红梅[1] 祁克宗[1] SONG Xiang-jun;JIANG Hu-yan;HOU Man-man;TU Jian;SHAO Ying;LIU Hong-mei;QI Ke-zong(Anhui Agricultural University,Key Laboratory of Veterinary Pathophysiology and Disease Prevention and Control in Anhui Province,Hefei 230036,China)

机构地区：[1]安徽农业大学兽医病理生物学与疫病防控安徽省重点实验室

出　　处：《中国预防兽医学报》2019年第10期1009-1014,1020,共7页Chinese Journal of Preventive Veterinary Medicine

基　　金：国家自然科学基金项目(31802161、31772707);安徽农业大学引进与稳定人才项目(yj2017-31);安徽农业大学校长青年基金重点项目(2017zd01)

摘　　要：为研究OmpT对禽致病性大肠杆菌(APEC)生物学特性和致病性的影响,本实验通过Red同源重组方法构建了APEC AE17菌株omp T缺失株(ΔompT)及回复株(ΔompT-comp),检测ompT基因缺失后对APEC生长速率、运动性、抗吞噬能力、组织载菌量、致病力以及基因表达量的影响。实验结果显示:ΔompT在生长速率、运动性及抗巨噬细胞吞噬方面与野生株相比差异不显著;其在雏鸡肝脏、脾脏、肺脏的载菌量均下降;LD50试验结果显示缺失株的致病力下降10倍。RNA-Seq分析结果显示ΔompT与野生株相比差异表达的基因共有490个,其中有365个基因表达上调,125个基因表达下调;生物信息学分析结果显示差异基因富集ABC转运通路、鞭毛装配以及脂多糖生物合成等重要通路。本研究发现ompT基因缺失后引起细菌基因表达量变化,并且导致APEC的致病性降低,该研究结果为APEC致病机理的研究提供了参考依据。To study the effects of OmpT on the biological characteristics and pathogenicity of avian pathogenic Escherichia coli(APEC), we constructed the ompT mutant strain(ΔompT) by Red recombination system and the corresponding complementary strain(ΔompT-comp), and tested the effects of omp T gene deletion on APEC growth rate, motility, anti-phagocytic ability, bacterial load in tissues, pathogenicity, and gene expression. The results showed that the growth rate, motility, and,anti-macrophage phagocytic ability of ompT gene mutant strain were not significantly different from the wildtype strain. In the experiment of animal infection, the bacterial load in liver, spleen, and lung decreased. Further studies showed that deletion of ompT gene reduced the pathogenicity by 10-fold based on the measurement of the LD50. RNA-Seq analysis revealed that compared with the wildtype strain, there were 490 genes differentially expressed in the ompT gene mutant strain, among which 365 genes were up-regulated and 125 genes were down-regulated. Bioinformatics analysis showed that differentially expressed genes were enriched in pathways such as ABC transport pathway, flagella assembly, and lipopolysaccharide biosynthesis. In conclusion, our investigation established that deletion mutant of ompT caused changes in bacterial gene expression and reduced the pathogenicity of APEC, and thus provided valuable information for studying the pathogenesis of APEC.

关 键 词：禽致病性大肠杆菌 OMPT 生物学特性 致病性 

分 类 号：S855.1[农业科学—临床兽医学]