Microbial survey of bacterial contamination of shellfish products in Wenzhou / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the status of bacterial contamination in the shellfish products in Wenzhou.</p><p><b>METHODS</b>One hundred samples were collected and their bacterial populations including the total plate count were investigated.</p><p><b>RESULTS</b>Of the 100 samples collected, 67 samples failed to not meet the national regulations due to bacterial contamination, accounting for 67% of the total samples. Among the contaminated samples, the most serious contamination was caused by coliforms (61.4% of the total plate count with contamination), followed by Salmonella (18.6%), Vibio parahaemolyticus (15.7%), Listeria spp. (4.3%) and others (6%).</p><p><b>CONCLUSION</b>Microbial pollution has become a threat to the marine shellfish products in Wenzhou.</p>

Cloning, expression and identification of flaB gene from a clinical isolate of Helicobacter pylori / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To clone Helicobacter pylori flagellin B gene (flaB) to construct prokaryotic expression system of the gene and to identify immunity of the fusion protein.</p><p><b>METHODS</b>The flaB gene from a clinical isolate Y06 of H.pylori was amplified by high fidelity PCR. The nucleotide sequence of the target DNA amplification fragment was sequenced after T-A cloning. The expression vector pET32a with inserted flaB gene was constructed. FlaB fusion protein was expressed in E.coli strain BL21DE3 inducted by IPTG at different dosages. Western blot was applied to determine immunoreactivity and immunogenicity of the fusion protein and antibody against whole cell of H.pylori and rabbit antiserum immunized with the fusion protein, respectively.</p><p><b>RESULTS</b>In comparison with the reported corresponding sequences, the homology of nucleotide sequence of the cloned flaB gene was from 96.31% approximate, equals 97.73%, while the homology of its putative amino acid sequence was as high as 99.41% approximate, equals 100%. The expression output of FlaB fusion protein in pET32a-flaB-BL21DE3 system was approximately 40% of the total bacterial proteins. FlaB fusion protein was able to combine with antibody against whole cell of H.pylori and induce rabbit to produce specific antibody with high titer after the animal was immunized with the protein.</p><p><b>CONCLUSION</b>A prokaryotic expression system of H. pylori flaB gene with high efficiency has been established successfully. The expressed FlaB fusion protein with satisfactory immunogenicity and immunoreactivity can be used as antigen in H.pylori vaccine and detect kit.</p>