Yang Yang

Publications (3)5.26 Total impact

• Article: [Cloning, expression and activity of K99 fimbrial operon gene from enterotoxigenic Escherichia coli].

  Yang Yang, Huayan Hou, Lei Yu, Guoqiang Zhu
  [show abstract] [hide abstract]
  ABSTRACT: To clone and express fan operon gene clusters of K99 fimbriae in enterotoxigenic Escherichia coli (ETEC) in vitro, and study the activity of the recombinant E. coli expressing K99 fimbriae. K99 fimbriae gene clusters were amplified by long-PCR method, using the genomic DNA of K99-fimbriae E. coli C8307 as the DNA template. The 5.7Kb PCR products were inserted into expressing vector pBR322 with restriction endonuclease, then positive clones were screened. The positive recombinant plasmid was transformed into non-fimbriae E. coli SE5000 strains, and pBR322 plasmid was also transformed into SE5000 for negative control strain. The recombination E. coli expressing K99 fimbriae was tested with agglutination assay, using monoclonal antibody serum and brush border vesicles from the piglet small intestinal epithelia cells. The expressed fimbriae on the surface of the recombinant E. coli SE5000 were observed by transmissible electromicroscope. Heat extraction method was employed to isolate and purify K99 fimbriae, which was exerted SDS-PAGE, and 18.5 kDa protein band was detected. The mouse sera produced from recombinant fimbriae was used to test K99-fimbriae strains C83907, C83914, C83260 with positive agglutination results, while negative results were found with E. coli contain other kinds of fimbriae. The assays of SDS-PAGE, Western blot, agglutination assay were used to evaluate antigenicity and biologic activity between C83907 and recombinant strain. Adhesion test with HeLa cell line demonstrated the recombinant strain and wild type have the similar adherence ability, and this adhesion can be inhibited with mouse serum containing polyclonal antibody against recombinant K99 fimbriae. This study has laid a good foundation for further study on bioactivity of K99.
  ACTA MICROBIOLOGICA SINICA 12/2012; 52(12):1524-30.
• Article: Flagella from F18+Escherichia coli play a role in adhesion to pig epithelial cell lines.

  Qiangde Duan, Mingxu Zhou, Xiaofang Zhu, Yang Yang, Jun Zhu, Wenbin Bao, Shenglong Wu, Xiaosai Ruan, Weiping Zhang, Guoqiang Zhu
  [show abstract] [hide abstract]
  ABSTRACT: F18 fimbriae and toxins produced by F18 fimbriae-carrying Escherichia coli (E. coli) strains are known virulence factors responsible for post-weaning diarrhea (PWD) and edema disease (ED). In this study, we showed that fliC isogenic mutants constructed in two reference wild-type F18 fimbriae (F18+) E. coli were markedly impaired in adherence in vitro cell models (p < 0.05). Flagella purified from F18+E. coli could directly bind to cultured piglet epithelial cells and block adherence of F18+E. coli to cells when pre-incubated. In addition, the F18+E. coli fliC deletion mutants up-regulated the expression of type I fimbriae produced by F18+E. coli strains. These results demonstrated that expression of flagella is essential for the adherence of F18+E. coli in vitro.
  Microbial Pathogenesis 10/2012; · 1.94 Impact Factor
• Article: The flagella of F18ab Escherichia coli is a virulence factor that contributes to infection in a IPEC-J2 cell model in vitro.

  Qiangde Duan, Mingxu Zhou, Xiaofang Zhu, Wenbin Bao, Shenglong Wu, Xiaosai Ruan, Weiping Zhang, Yang Yang, Jun Zhu, Guoqiang Zhu
  [show abstract] [hide abstract]
  ABSTRACT: Bacterial flagella contribute to pathogen virulence; however, the role of flagella in the pathogenesis of F18ab E. coli-mediated swine edema disease (ED) is not currently known. We therefore evaluated the role of flagella in F18ab E. coli adhesion, invasion, biofilm formation, and IL-8 production using an in vitro cell infection model approach with gene-deletion mutant and complemented bacterial strains. We demonstrated that the flagellin-deficient fliC mutant had a marked decrease in the ability to adhere to and invade porcine epithelial IPEC-J2 cells. Surprisingly, there was no difference in adhesion between the F18 fimbriae-deficient ΔfedA mutant and its parent strain. In addition, both the ΔfedA and double ΔfliCΔfedA mutants exhibited an increased ability to invade IPEC-J2 cells compared to the wild-type strain, although this may be due to increased expression of other adhesins following the loss of F18ab fimbriae and flagella. Compared to the wild-type strain, the ΔfliC mutant showed significantly reduced ability to form biofilm, whereas the ΔfedA mutant increased biofilm formation. Although ΔfliC, ΔfedA, and ΔfliCΔfedA mutants had a reduced ability to stimulate IL-8 production from infected Caco-2 cells, the ΔfliC mutant impaired this ability to a greater extent than the ΔfedA mutant. The results from this study clearly demonstrate that flagella are required for efficient F18ab E. coli adhesion, invasion, biofilm formation, and IL-8 production in vitro.
  Veterinary Microbiology 05/2012; 160(1-2):132-40. · 3.33 Impact Factor