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Abstract: Duck circovirus (DuCV) is classified in the genus Circovirus of the Circoviridae family. Two major open reading frames (ORFs), encoding the replicase (ORF1/rep) and the capsid protein (ORF2/cap), have been recognized for DuCV. Sequence analysis show that another major conserved ORF (named ORF3) is located in the complementary strand of ORF1/rep of DuCV, and its function remains to be investigated. In this study, the ORF3 of DuCV was expressed in recombinant baculovirus-infected Sf9 cells. By IFA and Western blot analysis, the ORF3 protein was positive for the sera from ducks infected with DuCV. The percentages of apoptotic cells of the Sf9 cells infected with the recombinant baculovirus encoding ORF3 of DuCV were significantly higher than (P <0.05) that of the Sf9 cells infected with wild-type baculovirus at 24, 48 and 72h postinfection. Based on our knowledge, we deduced that the ORF3 protein of DuCV might play an important role in viral pathogenesis via its apoptotic activity. [Copyright &y& Elsevier]

Peoniflorin (PF), extracted from the root of Pall., has been reported to have anti-inflammation and antioxidant effects in several animal models. Herein, we investigated the protective effects of PF against hydrogen peroxide (H2O2)-induced oxidative damage in human umbilical vein endothelial cells (HUVECs). HUVECs were treated by H2O2 (240 µmol/L) with or without PF. PF significantly increased the percent cell viability of HUVECs injured by H2O2 using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. By flow cytometric analysis, PF markedly attenuated H2O2-induced apoptosis and intracellular reactive oxygen species production. In addition, PF also displayed a dose-dependent reduction of lactate dehydrogenase leakage, malondialdehyde formation, and caspase-3 proteolytic activities in H2O2-treated cells, which was accompanied with a restoration of the activities of endogenous antioxidants, including total superoxide dismutase and glutathione peroxidase. Finally, Western blot data revealed that H2O2 upregulated phosphorylation of extracellular signal-regulated kinase 1/2 in HUVECs, which was almost completely reversed by PF. Taken together, our data provide the first evidence that PF has a protective ability against oxidative damage in HUVECs. PF may be a candidate medicine for the treatment of vascular diseases associated with oxidative stress. [ABSTRACT FROM AUTHOR]