To investigate the Mycoplasma hyopneumoniae(Mhp) P159 adhesion activity,the 3' end of P159 gene fragment was amplified by PCR from Mhp NJ strain,and inserted into expression vector pET-28a(+) for expression in E.coli.The results showed that the target gene was 450 bp.Molecular weight of the recombinant protein was 46 ku by SDS-PAGE detection and westem blot analysis indicated that the recombinant protein had specific reaction with pig anti Mhp serum.Furthermore,the recombinant protein was able to adhere to porcine lung epithelial cells and partially blocked the Mhp to adhere the cell which was specially inhibited by anti Mhp serum.The results provide a basis for the further study on the pathogenesis of Mhp.

Mycoplasma hyopneumoniae is the etiological agent of Mycoplasma pneumonia of Swine(MPS).Its adhesins play an important role in the pathogenesis process.In this article,some adhesins of Mycoplasma hyopneumoniae and other Mycoplasmas in the latest reseach at home and abroad were discussed,so as to provide new ideas for the further research on the pathogenesis of Mycoplasma hyopneumoniae and the prevention of the disease.

This experiment was conducted to study the adhesion activity of P216 protein and establish the model of adhesion protein of Mycoplasma hyopneumoniae(Mhp).According to analysis,the fragment of P216 gene with hydrophilicity,antigenicity and good adhesion was chose.P216 gene fragment was amplified by PCR from Mhp NJ strain and inserted into expression vector pET-32a(+),and the recombinant plasmid pET-32a(+)/P216 was constructed.After IPTG induction,the immunological and adhesion activity of the recombined protein was detected by Western blot and indirect immunofluorescence assay.The results showed that,the PCR product of the target gene was l 636 bp,the molecular weight of recombinant protein was 80.1 kDa by SDS-PAGE,and Western blot results showed that recombinant protein had satisfactory immunogenicity.Indirect immunofluorescence assay showed that the recombinant protein could produce occupied inhibition to the Mhp adhering with SJPL cells.These results indicated that the P216 protein had good adhesion activity,and could adhere SJPL cells.It provides new ideas for research of the other adhesions from Mycoplasma hyopneumoniae.

Mycoplasma hyopneumoniae （Mhp） is the etiologic agent of mycoplasma pneumonia in swine. In this study the DnaK gene of strain NJ is amplified by gene splicing with overlap extension PCR using a pair of inside-mutation primers. The PCR product is inserted into expression plasmid pET-28a （＋）. The recombinant plasmid is transformed into competent cells of BL21（DE3） and it contains correct object fragments by sequencing. It is induced to express by 1 mmol/L IPTG at 37 ~C for 5 hours. The dose of the recombinant protein is nearly 14. 1~ of the total product. The expression product of interest and its biological activities are characterized with Western blotting and ELISA analysis. This study provides the basis for diagnose agent and future preparation of new vaccine a~ainst Mvconlasma hvonneurnnniae.