title: The AS87_04050 gene is involved in bacterial lipopolysaccharide biosynthesis and pathogenicity of Riemerella anatipestifer.
abstract: Riemerella anatipestifer is reported worldwide as a cause of septicemic and exudative diseases of domestic ducks. In this study, we identified a mutant strain RA2640 by Tn4351 transposon mutagenesis, in which the AS87_04050 gene was inactivated by insertion of the transposon. Southern blot analysis indicated that only one insertion was found in the genome of the mutant strain RA2640. SDS-PAGE followed by silver staining showed that the lipopolysaccharide (LPS) pattern of mutant strain RA2640 was different from its wild-type strain Yb2, suggesting the LPS was defected. In addition, the phenotype of the mutant strain RA2640 was changed to rough-type, evident by altered colony morphology, autoaggregation ability and crystal violet staining characteristics. Bacterial LPS is a key factor in virulence as well as in both innate and acquired host responses to infection. The rough-type mutant strain RA2640 showed higher sensitivity to antibiotics, disinfectants and normal duck serum, and higher capability of adherence and invasion to Vero cells, compared to its wild-type strain Yb2. Moreover, the mutant strain RA2640 lost the agglutination ability of its wild-type strain Yb2 to R. anatipestifer serotype 2 positive sera, suggesting that the O-antigen is defected. Animal experiments indicated that the virulence of the mutant strain RA2640 was attenuated by more than 100,000-fold, compared to its wild-type strain Yb2. These results suggested that the AS87_04050 gene in R. anatipestifer is associated with the LPS biosynthesis and bacterial pathogenicity.
authors.affiliation: Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China.
authors.forename: Xiaolan
authors.initials: X
authors.lastname: Wang
authors.affiliation: Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China.
authors.forename: Chan
authors.initials: C
authors.lastname: Ding
authors.affiliation: Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China.
authors.forename: Shaohui
authors.initials: S
authors.lastname: Wang
authors.affiliation: Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China.
authors.forename: Xiangan
authors.initials: X
authors.lastname: Han
authors.affiliation: Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China.
authors.forename: Wanwan
authors.initials: W
authors.lastname: Hou
authors.affiliation: Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China.
authors.forename: Jiaping
authors.initials: J
authors.lastname: Yue
authors.affiliation: Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China.
authors.forename: Jiechi
authors.initials: J
authors.lastname: Zou
authors.affiliation: Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China.
authors.forename: Shengqing
authors.initials: S
authors.lastname: Yu
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D002448:Cell Adhesion / Q000502:physiology; D002522:Chlorocebus aethiops; D004372:Ducks; D008070:Lipopolysaccharides / Q000096:biosynthesis*; D011201:Poultry Diseases / Q000382:microbiology*; D060494:Riemerella / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity*; D014709:Vero Cells; D014774:Virulence
chemical_list: D001426:Bacterial Proteins; D008070:Lipopolysaccharides