Search

The effects of radiation and ice clouds on a torrential rainfall event of Jiang-Huai Valley over China are investigated through a series of two-dimensional sensitivity cloud-resolving model experiments. The model is integrated with an imposed large-scale vertical velocity and zonal wind constructed from the National Centers for Environmental Prediction (NCEP)/Global Data Assimilation System (GDAS) from 2 to 9 July 2007, while the control experiment is compared with two sensitivity experiments that exclude radiation and ice clouds, respectively. The exclusion of ice clouds decreases model domain mean surface rain rate through the weakened mean net condensation and the mean hydrometeor change from loss to gain during the life span of the rainfall event. The sensitivity of the mean rain rate to radiation occurs only in the later period of the rainfall event and is less than that to ice clouds. The reduction in the mean rain rate caused by the elimination of radiation is associated with the decreases in the mean net condensation and latent heat, which corresponds to the strengthened mean local atmospheric cooling.

Enterovirus 71 (EV71) infection causes hand-foot-and-mouth disease that leads to cardiopulmonary complications and death in young children. There is thus an urgent need to find new treatments to control EV71 infection. In this study, we report potent inhibition of EV71 by a polyene antibiotic Amphotericin B. Amphotericin B profoundly diminished the expression of EV71 RNA and viral proteins in the RD cells and the HEK293 cells. As a result, EV71 production was inhibited by Amphotericin B with an EC50 (50% effective concentration) of 1.75 μM in RD cells and 0.32 μM in 293 cells. In addition to EV71, EV68 was also strongly inhibited by Amphotericin B. Results of mechanistic studies revealed that Amphotericin B targeted the early stage of EV71 infection through impairing the attachment and internalization of EV71 by host cells. As an effective anti-fungi drug, Amphotericin B thus holds the promise of formulating a novel therapeutic to treat EV71 infection.

Background Interferon protects cells from virus infection by inducing the expression of genes with antiviral activities. One such antiviral gene is Mx (myxovirus resistance) that was first identified in mice for its protection against influenza virus infection. Humans carry two Mx genes, MxA and MxB. Although MxA has been reported to inhibit a number of RNA and DNA viruses, the antiviral function of MxB has just begun to be revealed.

Background Tetherin (also known as BST-2, CD317, and HM1.24) is an interferon- induced protein that blocks the release of a variety of enveloped viruses, such as retroviruses, filoviruses and herpesviruses. However, the relationship between tetherin and foamy viruses has not been clearly demonstrated. Results In this study, we found that tetherin of human, simian, bovine or canine origin inhibits the production of infectious prototypic foamy virus (PFV). The inhibition of PFV by human tetherin is counteracted by human immunodeficiency virus type 1 (HIV-1) Vpu. Furthermore, we generated human tetherin transmembrane domain deletion mutant (delTM), glycosyl phosphatidylinositol (GPI) anchor deletion mutant (delGPI), and dimerization and glycosylation deficient mutants. Compared with wild type tetherin, the delTM and delGPI mutants only moderately inhibited PFV production. In contrast, the dimerization and glycosylation deficient mutants inhibit PFV production as efficiently as the wild type tetherin. Conclusions These results demonstrate that tetherin inhibits the release and infectivity of PFV, and this inhibition is antagonized by HIV-1 Vpu. Both the transmembrane domain and the GPI anchor of tetherin are important for the inhibition of PFV, whereas the dimerization and the glycosylation of tetherin are dispensable.