Objective To express recombinant Burkholderia pseudomallei(B.pseudomallei)type Ⅲ secretion system BipD protein,prepare its polyclonal antibodies and verify their immunological traits.Methods The recombinant pET-28a-BipD plasmid was generated,and the pET-28a-BipD-carried E.coli BL21(DE3)bacteria were induced with isopropyl-β-d-thiogalactoside(IPTG)to express recombinant BipD(rBipD)protein.The rBipD was obtained by affinity chromatography using His Trap column,then mixed with Fredrick's adjuvant to immunize BALB/c mice by intraperitoneal injection in order to obtain anti-rBipD polyclonal antibodies.The immunoreactivity of rBipD was detected by Western blot assay using rabbit anti-melioidosis serum and the serum from melioidosis patients.The immunogenicity of rBipD was evaluated using Western blotting and immunofluorescence staining.Finally,rBipD was used to establish an indirect ELISA to detect serum antibodies of clinical melioidosis patients.Results The recombinant plasmid pET-28a-BipD was successfully constructed and transformed into E.coli BL21(DE3)to induce rBipD expression with IPTG treatment.The obtained rBipD had a relative molecular weight of 36×103 and a purity of 95.4％,and had good immunogenicity and immunoreactivity.It could induce the production of specific antibodies after immunizing mice,and mouse polyclonal antibodies against rBipD were prepared with the titer of 1∶512 000.rBipD of 5.0 μg/mL produced specific immune response with the serum of melioidosis patients,but had no specific reaction with the serum of tuberculosis patients,with statistical difference(P＜0.01).Conclusion rBipD with immunological activity is successfully prepared and purified,and its polyclonal antibodies are also developed,which provide a good tool for clinical immunological diagnosis and study of immune mechanism of B.pseudomallei infection.

Objective To analyze the mechanism that Hcp1 protein in type Ⅵ secretion system of Burkholderia pseudomallei(B.pseudomallei)mediates the formation of multinucleated giant cells(MNGCs)when host cells are infected by the bacterium.Methods The mutant strain(BPC006 Δhcp1)and complementation strain(BPC006 Δhcp1::hcp1)were constructed by homologous recombination and plasmid complement technology,respectively.After RAW264.7 cells were infected with B.pseudomallei,the localization of Hcp1 in host cells was analyzed by immunofluorescence staining.The localization was further verified by cytoplasmic-membrane isolation in 293T cells after transfecting pCDNA4.1-Hcp1.The biological significance and effect of Hcp1 were explored by the anti-Hcp1 polyclonal antibody blocking and the formation of MNGC was detected by Giemsa staining.Results Western blotting showed that BPC006 Δhcp1 could not express Hcp1,while BPC006 Δhcp1::hcp1 restored Hcp1 expression.The above results proved that the mutant and complement strains were successfully constructed.Both cellular immunofluorescence co-localization and cytoplasmic-membrane isolation experiments showed that Hcp1 localized to host cell membranes.Last but not least,compared with the control group,anti-Hcp1 polyclonal antibodies inhibited the formation of MNGC(P＜0.01).Conclusion Hcp1 protein in type Ⅵ secretion system of B.pseudomallei is able to translocate to the RAW264.7 cell membranes and plays an important role in the formation of MNGCs.

OBJECTIVE： To compare the difference in volatile oil constituents of Glehniae littoralis from 3 producing areas as Shandong Laiyang， Hebei Anguo， Inner Mongolian Chifeng. METHODS： The method of steam distillation was used to extract the volatile oil of G. littoralis from different areas and calculate the extraction rate. The constituents of volatile oil were analyzed by using GC-MS. The data was corrected by Xcalibur chemical workstation. The constituents were searched by NIST 11.0 mass spectrometry database （matching degree ＞800）， and the relative mass fraction of each chemical constituent was obtained by peak area normalization. RESULTS： The extraction rate of volatile oil in G. littoralis from Laiyang was 0.013％， which was far lower than G. littoralis from Anguo （0.099％） and G. littoralis from Chifeng （0.105％）. There were 15， 18 and 27 constituents identified in volatile oil of G. littoralis from 3 producing areas； the relative mass fractions were 89.29％， 96.76％， 94.53％. Falcarinol was a common compound with the highest relative mass fraction of the volatile oil of G. littoralis from different producing areas； the relative mass fractions were 69.79％， 90.89％ and 71.04％， respectively. Fatty acids were rich in the sample from Laiyang， while C15H24 sesquiterpenoids were rich in the other samples from Anguo and Chifeng. CONCLUSIONS： Volatile oil of G. littoralis could be used as potential chemical markers to distinguish different producing areas due to their significant differences in chemical components.