Inhibition of Hepatitis B Virus Replication by Rheum palmatum L. Ethanol Extract in a Stable HBV-producing Cell Line

Hepatitis B virus(HBV) infection is a severe health problem in the world. However, there is still not a satisfactory therapeutic strategy for the HBV infection. To search for new anti-HBV agents with higher efficacy and less side-effects, the inhibitory activities of traditional Chinese medicine Rheum palmatum L. ethanol extract(RPE) against HBV replication were investigated in this study. Quantitative real-time polymerase chain reaction(PCR) was employed to analyze the inhibitory activity of RPE against HBV-DNA replication in a stable HBV-producing cell line HepAD38; the expression levels of HBV surface antigen(HBsAg) and e antigen(HBeAg) were also determined by enzyme linked immunosorbent assay(ELISA) after RPE treatment. RPE could dose-dependently inhibit the production of HBV-DNA and HBsAg. The concentration of 50% inhibition(IC50) was calculated at 209.63, 252.53μg/mL, respectively. However, its inhibitory activity against HBeAg expression was slight even at high concentrations. RPE had a weak cytotoxic effect on HepAD38 cells(CC50 = 1 640μg/mL) and the selectivity index(SI) was calculated at 7.82. Compared with two anthraquinone derivatives emodin and rhein, RPE showed higher ability of anti-HBV and weaker cytotoxicity. So Rheum palmatum L. might possess other functional agents which could effectively inhibit HBV-DNA replication and HBsAg expression. Further purification of the active agents, identification and modification of their structures to improve the efficacy and decrease the cytotoxicity are required.     

Meconopsis wilsonii subsp. wilsonii (Papaveraceae) Rediscovered

Field studies in the Lamagetou Nature Reserve , Mianning Xian , Sichuan Province , in the summer of 2005 revealed a particularly rich and diverse flora . One particularly noteworthy plant growing in openings in the forest, at woodland margins and on exposed slopes, was the recently described Meconopsis wilsonii Grey-Wilson subsp. wilsonii (Papaveraceae) , a species previously known only from the type collection and last collected in 1908 , nearly 100 years ago.     

The Role of dinB in the Appearing of Antibiotics Resistance in E.coli

The role of dinB gene in the appearing of antibiotics resistance was studied. Plasmid containing multi-copy dinB gene was transfected into E. coli to create an overexpression. The strains carrying multi-copies of dinB gene demonstrate a significant survival advantage over the wild strain. In vitro experiment, the dinB-overexpressed strain evolved resistance within 8 hours, while wild strain could not.In vivo experiment with mice model infected with dinB-overexpressed strain, resistant clones emerged significantly earlier and demonstrated significant higher level of resistance than those infected with the wild control strain. The results showed that dinB gene made a contribution in the appearing of the antibiotics resistance and has a potential as a target for prevention from the appearing of antibiotic resistance.