Lipid rafts play an important role in the vesicular stomatitis virus life cycle.

Lipid rafts are involved in the life cycle of many viruses. In this study, we investigated the role of lipids in the life cycle of vesicular stomatitis virus (VSV). Cholesterol depletion by pretreatment of BHK cells or VSV particles with methyl-beta-cyclodextrin (MbetaCD), a cholesterol-sequestering drug, inhibited the production of VSV dramatically. This effect was reversible, and virus production was restored by the addition of cholesterol, indicating that the reduction was caused by the loss of cholesterol in the cell membrane and virus, respectively. Cholesterol depletion at the adsorption stage also reduced the production of VSV significantly, but in contrast, only had a limited effect on virus production at the post-entry stage. Inhibition of sphingomyelin by myriocin treatment only showed a minor effect on VSV production. However, reduction of cholesterol and sphingomyelin at the same time dramatically reduced VSV production, showed a significant synergistic effect. These results suggest that lipid rafts play an important role in the life cycle of VSV.

Antioxidative activity of Rosmarinus officinalis L. essential oil compared to its main components.

This study was designed to examine the in vitro antioxidant activities of Rosmarinus officinalis L. essential oil compared to three of its main components (1,8-cineole, α-pinene, ß-pinene). GC-MS analysis of the essential oil resulted in the identification of 19 compounds, representing 97.97% of the oil, the major constituents of the oil were described as 1,8-cineole (27.23%), α-pinene (19.43%), camphor (14.26%), camphene (11.52%) and ß-pinene (6.71%). The oil and the components were subjected to screening for their possible antioxidant activity by means of 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay and ß-carotene bleaching test. In the DPPH test system, free radical-scavenging activity of R. officinalis L. essential oil, 1,8-cineole, α-pinene and ß-pinene were determined to be 62.45%±3.42%, 42.7%±2.5%, 45.61%±4.23% and 46.21%±2.24% (v/v), respectively. In the ß-carotene bleaching test system, we tested series concentration of samples to show the antioxidant activities of the oil and its main components, whereas the concentrations providing 50% inhibition (IC50) values of R. officinalis L. essential oil, 1,8-cineole, α-pinene and ß-pinene were 2.04%±0.42%, 4.05%±0.65%, 2.28%±0.23% and 2.56%±0.16% (v/v), respectively. In general, R. officinalis L. essential oil showed greater activity than its components in both systems, and the antioxidant activities of all the tested samples were mostly related to their concentrations. Antioxidant activities of the synthetic antioxidant, ascorbic acid and BHT, were also determined in parallel experiments as positive control.

Scale correlation between vegetation and soil in larch forest, NE China.

After the analysis on the linages of species, the fractal dimensions of vegetation and soil in a managed larch(Larix gmelini) forest in Daxingan Mountains, NE China were estimated separately, and their scale correlation was discussed. (1) The dominant species of the larch forest, larch and the important accompany species, birch(Betula platyphylla) were homogeneously distributed along the transect. The other species were heterogeneous, and can be divided into three groups located on the right, left and central parts of the transect respectively. The transect can be separated into two parts at the position for the 29th quadrat(580 m). (2) The fractal dimension in the large scale range from 200 to 400 m was lower than that in the small scale range from 0 to 200 m in the forest, indicating the different variation regularities of spatial heterogeneity in different scale ranges. The inflection point at 200 m was one of the key scales of spatial hierarchy of the larch forest. (3) The scale variation of the forest was correlated with that of soil pH on large scales, which reflected the indirect control of the dominant species to the spatial pattern and species distribution of understorey by changing soil acidity in the forest and the indirect effects of forest management.