title: The waaL gene is involved in lipopolysaccharide synthesis and plays a role on the bacterial pathogenesis of avian pathogenic Escherichia coli.
abstract: Avian pathogenic Escherichia coli (APEC) is a Gram-negative bacterium that causes avian colibacillosis, resulting in economically devastating to poultry industries worldwide. Lipopolysaccharide (LPS) has been identified as an important virulence factor of E. coli. The waaL gene encodes O-antigen ligase, which is responsible for attaching the O-antigen to lipid A-core oligosaccharide. In this study, a mutant strain ΔwaaL was constructed from APEC serotype 2 strain DE17. The mutant strain showed a decreased swimming motility and resistance to complement-mediated killing but a similar growth rate in the culture, compared with its parent strain. In addition, the mutant LPS demonstrated different patterns in SDS-PAGE followed by silver staining and western blotting. Besides, the mutant strain significantly decreased its adherence and invasion abilities to DF-1 cells, compared to its parent strain DE17. Deletion of the waaL gene in DE17 reduced the bacterial virulence by 42.2-fold in ducklings, based on measurement of the median lethal dose (LD50). Additional analysis indicated that deletion of the waaL gene increased the biofilm formation ability and reduced the resistance to environmental stress. These results suggest that the waaL gene functions on the APEC LPS synthesis and bacterial pathogenesis.
authors: Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 518 Ziyue Road, Shanghai 200241, People's Republic of China.
authors: Yue
authors: Y
authors: Han
authors: Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 518 Ziyue Road, Shanghai 200241, People's Republic of China.
authors: Xiangan
authors: X
authors: Han
authors: Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 518 Ziyue Road, Shanghai 200241, People's Republic of China.
authors: Shaohui
authors: S
authors: Wang
authors: Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 518 Ziyue Road, Shanghai 200241, People's Republic of China.
authors: Qingmei
authors: Q
authors: Meng
authors: Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 518 Ziyue Road, Shanghai 200241, People's Republic of China.
authors: Yuxi
authors: Y
authors: Zhang
authors: Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 518 Ziyue Road, Shanghai 200241, People's Republic of China.
authors: Chan
authors: C
authors: Ding
authors: Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 518 Ziyue Road, Shanghai 200241, People's Republic of China. Electronic address: yus@shvri.ac.cn.
authors: Shengqing
authors: S
authors: Yu
mesh_terms: D000818:Animals; D019729:Carbon-Oxygen Ligases / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D002642:Chick Embryo; D004372:Ducks; D004926:Escherichia coli / Q000235:genetics; D004927:Escherichia coli Infections / Q000382:microbiology / Q000662:veterinary*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D005347:Fibroblasts / Q000382:microbiology; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology; D011201:Poultry Diseases / Q000382:microbiology*; D014774:Virulence; D037521:Virulence Factors / Q000235:genetics
chemical_list: D029968:Escherichia coli Proteins; D037521:Virulence Factors; D019729:Carbon-Oxygen Ligases; C571195:WaaL protein, E coli
keywords: Avian pathogenic Escherichia coli; Lipopolysaccharide; Pathogenesis; waaL mutant