Cloning and expression of duck C4BPα and verification of its interaction with Riemerella anatipestifer / 生物工程学报

To study the interaction between C4b-binding protein (C4BP) and Riemerella anatipestifer (RA), we cloned duck C4BPα, conducted prokaryotic expression and prepared the polyclonal antibody by immunizing mice. Then indirect immunofluorescence assay and dot blotting hybridization assay were used to verify the interaction between C4BP and RA. The full length of duck C4BPα nucleotide sequence was 1 230 bp, with the highest similarity to chicken C4BPα (82.1%). Phylogenetic tree analysis showed that duck C4BPα and chicken C4BPα were on the same phylogenetic tree branch and the genetic evolution relationship between them was the closest. C4BPα was efficiently expressed in Escherichia coli BL21 (DE3). The recombinant proteins existed in intracellular soluble form. The titer of polyclonal antibody was more than 1:10 000 and polyclonal antibodies could specifically recognize the recombinant proteins. The results of indirect immunofluorescence assay and dot blot hybridization assay showed that RA could interact with duck C4BP. The results provide a basis to further reveal the pathogenesis of RA.

Effect of Helicobacter pylori infection on bacterial flora in the lower esophagus of mice / 南方医科大学学报

<p><b>OBJECTIVE</b>To explore the relationship between Helicobacter pylori (H. pylori) infection and lower esophageal diseases in light of the changes of the bacterial flora in the lower esophagus.</p><p><b>METHODS</b>Thirty BALB/C mice were randomized into negative control group and H. pylori infection group, and in the latter group, the mice were subjected to intragastric administration of solution containing H. pylori. After 4 weeks of administration, all the mice were sacrificed, and the V6 areas in 16S rDNA were amplified from the bacterial DNA extracted from the lower esophagus using polymerase chain reaction-denaturing gradient gel electrophoresis. The bacterial floras were analyzed on DGGE atlas with Quantity-One 1-D analysis software, and the differential bands between the two groups were amplified using a 16S rDNA v6 area primer followed by DNA sequencing and BLAST analysis.</p><p><b>RESULTS</b>DGGE finger-prints showed a significantly greater number of DNA bands in the infection group than in the negative control group (P<0.01). The diversity index and richness index were also significantly higher in the infection group (0.01<P<0.05). Bacterium cluster class analysis well separated the dendrogram in the infection group. Principal component analysis showed that different groups of bacteria gathered in different locations, and BLAST analysis revealed the presence of special bacteria in the infection group.</p><p><b>CONCLUSION</b>In normal mice, Lactobacillus and the Bacteroides are the predominant bacterial flora colonizing in the lower esophagus, and Staphylococcus, Acinetobacter and Bacteridium become the predominant bacteria after H. pylori infection.</p>