Objective Using chemically synthesized small interfering RNA (siRNA) transfected HepG2.2.15 cells to construct a cell model in interfering hepatitis B virus (HBV) X gene, studying the inhibi-tion of HBV replication and antigen expression in vitro. Methods After transfection of HepG2.2.15 cell for 24 h, 48 h, 72 h, detecting the cell supernatant of HBsAg and HBeAg by chemiluminescence immunoassay, the cell supernatant HBxAg protein by ELISA , the HBx mRNA relative expression of transfected cell was detected by fluorescence quantitative polymerase chain reaction (PCR), the ability of cell proliferation was detected by CCK-8 assay. Results After HBx-siRNA transfected HepG2.2.15 cells, cell proliferation ability was inhibited. The cell of HBx mRNA and the cell supernatant of HBxAg expression decreased (P < 0.05); at the same time it in-hibited the expression of HBsAg and HBeAg. The suppressed peak and the inhibition rate were 66% and 58%respectively at 72 h. The fluorescence quantitative PCR confirmed that expression of HBV DNA in the super-natant was decreased. Conclusion The HepG2.2.15 cell interference model of HBV X gene has been success-fully constructed, which has an effect of inhibiting proliferation of HepG2.2.15 cells and replication and expres-sion of HBV gene in vitro.

Objective : To investigate the role of iron uptake⁃related gene iucA in the pathogenesis of Uropathogenic E. coli(UPEC) , UPEC CFT073 strain was used to construct the iucA gene deletion strain ΔiucA by λ Red homologous recombination technology , and the complemented strain C ⁃iucA was also constructed. Methods : The proliferation rates of CFT073 , ΔiucA and C ⁃iucA in Luria⁃Bertani liquid medium and sterile urine were determined by measuring the absorbance at 600 nm. Cultured 5637 human bladder cancer epithelial cells confluent monolayers were incubated with CFT073 , ΔiucA and C ⁃iucA for adhesion and invasion ability assay. C57BL/6 mouse urinary tract infection model was constructed to assess colonization ability of CFT073 , ΔiucA and C ⁃iucA in murine bladder tissues. Results : Data showed that CFT073 , ΔiucA and C ⁃iucA displayed the similar proliferation curves in LuriaBertani liquid medium(P = 0. 153) . The proliferation rate of △iucA in sterile urine was lower than that of CFT073 ( P = 0. 001) , while the proliferation rate of C ⁃iucA in sterile urine was significantly higher than that of ΔiucA (P = 0. 005) . △iucA demonstrated much lower adhesion and invasion ability compared with CFT073 ( P = 0. 007 , 0. 002) , and C ⁃iucA showed significantly higher adhesion and invasion ability than △iucA( P = 0. 046 , 0. 037) . The colonization ability of △iucA in murine bladder tissues was much lower than that of CFT073 and C ⁃iucA(P = 0. 002 , 0. 017) . Conclusion The results indicate iucA gene may contribute to the proliferation , adhesion , invasion and colonization ability of UPEC.