Wang Yz

Autophagy favors Brucella melitensis survival in infected macrophages

This study investigated the role of autophagy in the survival of the invasive bacterium Brucella melitensis strain 16M in murine macrophages. Here, Brucella melitensis 16M was found to trigger autophagosome formation, enhance autophagy flux and increase the expression level of the autophagy marker protein LC3-II. When autophagy was pharmacologically inhibited by 3-methyladenine (3-MA), Brucella replication efficiency was significantly decreased (p < 0.05). These results suggest that autophagy favors Brucella melitensis 16M survival in murine macrophages.

ΦC31 integrase mediates efficient site-specific integration in sheep fibroblasts.

ΦC31 integrase, a site-specific recombinase, can effectively mediate the integration of foreign genes bearing an attB sequence into pseudo attP sites of genomes in human, mouse, and Drosophila cells. In this study, we measured ΦC31 integrase-mediated homologous recombination between attB and pseudo attP sites in sheep cells. The integration efficiency of the EGFP expression cassette with the attB sequence increased at least 2-fold in sheep fibroblasts. Three pseudo-attP sites were identified in the sheep genome, located in the intergenic regions on chromosomes 4, 13, and 7 respectively. Moreover, the transgene that was integrated at the three pseudo attP sites exhibited high levels of expression. Our study indicates that the ΦC31 integrase system provides an efficient integration tool for genetic engineering of the sheep genome.

Determination of some metabolites of Cordyceps sobolifera

Cordyceps sobolifera is an edible Chinese native medicinal material. Profiles of mannitol, polysaccharides, total saponins and total flavonoids in 12 populations of C. sobolifera were analyzed to evaluate the characteristics of this species. The amount of mannitol was uniformly distributed among the populations, which ranged from 5.78 to 10.91 g/100 g. The highest point reached by polysaccharide was 2.27 g/100 g and the lowest point was 0.35 g/100 g. It was the first report on content of total saponins in C. sobolifera and it was found not to be so rich in C. sobolifera. The highest amount of total flavonoids was 1.28 g/100 g. Mannitol was higher in stroma (11.37 g/100 g) than the one in sclerotium (6.42 g/100 g). It suggested that C. sobolifera might be a good source of mannitol. However, polysaccharide, total saponins and total flavonoids contents in the stroma were not different from those in the sclerotium.

Outer Membrane Protein 25 of Brucella Activates Mitogen-Activated Protein Kinase Signal Pathway in Human Trophoblast Cells

Outer membrane protein 25 (OMP25), a virulence factor from Brucella, plays an important role in maintaining the structural stability of Brucella. Mitogen-activated protein kinase (MAPK) signal pathway widely exists in eukaryotic cells. In this study, human trophoblast cell line HPT-8 and BALB/c mice were infected with Brucella abortus 2308 strain (S2308) and 2308ΔOmp25 mutant strain. The expression of cytokines and activation of MAPK signal pathway were detected. We found that the expressions of tumor necrosis factor-α, interleukin-1, and interleukin-10 (IL-10) were increased in HPT-8 cells infected with S2308 and 2308ΔOmp25 mutant. S2308 also activated p38 phosphorylation protein, extracellular-regulated protein kinases (ERK), and Jun-N-terminal kinase (JNK) from MAPK signal pathway. 2308ΔOmp25 could not activate p38, ERK, and JNK branches. Immunohistochemistry experiments showed that S2308 was able to activate phosphorylation of p38 and ERK in BABL/c mice. However, 2308ΔOmp25 could weakly activate phosphorylation of p38 and ERK. These results suggest that Omp25 played an important role in the process of Brucella activation of the MAPK signal pathway.

The impact of human activity on the biomass allocation of a medicinal herbaceous species in an agroforestry system of Southwest China

Human activity has a greater influence on plants than on any of the other components of the environment. We used material from cultivated and wild Coptis teeta populations in the Hengduan Mountains to test the null hypothesis that there is no effect of human activity on the biomass allocation of an herbaceous understory species in a forest ecosystem. At the plot level, an isometric relationship existed in most of the significant relationships. However, at the individual level, an allometric relationship existed in most of the log–log relationships. Human activity could significantly affect the slope of the linear relationship of leaf versus total biomass; and also the intercepts of the relationships of root biomass versus total biomass, plant height versus total biomass and reproductive versus vegetative biomass. At any given plant body size, wild C. teeta has higher biomass in the leaf and less in root than cultivated counterpart. But the trajectories of log rhizome biomass versus log total biomass were the same for both cultivated and wild individuals. Thus, we conclude that (1) the allometric trajectories change at different scales and (2) C. teeta-based agroforestry system could ensure sustainable use of this medicinal plant because of the stable biomass allocation to the salable rhizome organs.