促性腺激素(LH,FSH)对鸡卵泡孕酮分泌的影响

摘出垂体12 h 后的卵泡孕酮(P_4)浓度显著下降.单独添加 LH 时第一卵泡(F_1)的P_4浓度显著增加,同时添加 LH 和 FSH 时,所有卵泡的颗粒层 P_4浓度恢复到对照的水平.但是单独添加 FSH 时无促进作用.LH 和 FSH 的处理对卵泡的卵泡膜 P_4浓度影响极小.在细胞培养液中添加 LH 和 FSH 可以促进颗粒层的 P_4合成,这种反应以 F_1最为明显.LH 和 FSH同时添加时对颗粒层 P_4合成有显著效果,但是对卵泡膜 P_4合成无明显促进作用.表明 P_4在 LH和 FSH 的协同调控下,主要在 F_1的颗粒层中合成.     

Role of adaptor TRIF in the MyD88-independent toll-like receptor signaling pathway

Stimulation of Toll-like receptors (TLRs) triggers activation of a common MyD88-dependent signaling pathway as well as a MyD88-independent pathway that is unique to TLR3 and TLR4 signaling pathways leading to interferon (IFN)-beta production. Here we disrupted the gene encoding a Toll/IL-1 receptor (TIR) domain-containing adaptor, TRIF. TRIF-deficient mice were defective in both TLR3- and TLR4-mediated expression of IFN-beta and activation of IRF-3. Furthermore, inflammatory cytokine production in response to the TLR4 ligand, but not to other TLR ligands, was severely impaired in TRIF-deficient macrophages. Mice deficient in both MyD88 and TRIF showed complete loss of nuclear factor kappa B activation in response to TLR4 stimulation. These findings demonstrate that TRIF is essential for TLR3- and TLR4-mediated signaling pathways facilitating mammalian antiviral host defense.     

Plant growth inhibitory activity and active substances with allelopathic potential of cogongrass (Imperata cylindrica) rhizome

Cogongrass (Imperata cylindrica [L.] Raeusch.) is a perennial rhizomatous grass that belongs to the Poaceae and is widely distributed in tropical, subtropical and temperate regions over the world. The grass is strongly invasive and is suggested to have allelopathic potential. However, limited information is available on allelopathic substances in cogongrass rhizomes. Therefore, the allelopathic potential and substances in cogongrass rhizomes were investigated. The extracts of cogongrass rhizomes inhibited the root and shoot growth of barnyard grass, ryegrass, timothy, cress, lettuce and alfalfa. After bioassay‐guided separations of the extracts, four growth inhibitory substances, 5‐methoxyflavone, 5,2′‐dimethoxyflavone, methyl caffeate and abscisic acid, were isolated. 5‐Methoxyflavone, 5,2′‐dimethoxyflavone and methyl caffeate significantly inhibited the root and shoot growth of cress at concentrations of ≥0.03–0.3 m mol L^?1 and their concentrations required for 50% growth inhibition were 0.079–0.24, 0.23–1.1 and 0.59–0.88 m mol L^?1, respectively. The other isolated substance, abscisic acid, has been reported to have strong growth inhibitory activity. Its concentrations required for 50% growth inhibition on cress were 0.31–0.61 μ mol L^?1. The present study suggests that cogongrass rhizomes might have allelopathic potential and that those four substances might contribute to that potential.     

Effect of Steel Slag to Improve Soil Quality of Tsunami-Impacted Land while Reducing the Risk of Heavy Metal Bioaccumulation

After the tsunami caused by the Great East Japan Earthquake, marine sediment was taken from the sea bottom and deposited over local agricultural fields. The marine sediment already contained an unknown amount of heavy metals, due to anthropogenic activities prior to the tsunami, which might affect plants, animals, and humans. Furthermore, soil salinity in tsunami-inundated land greatly increased. Three different amounts of steel slag were employed as pretreatment agent in order to improve agricultural soil quality. The soil samples treated with 2% of steel slag present a remarkable increase of A. thaliana biomass production with low BCF and TF values for most of the heavy metals. It was concluded that steel slag pretreatment used in the tsunami-inundated agricultural lands produced a noteworthy improvement in soil quality which lead to a positive stimulative effect on plant growth, and the slag addition treatment proved to be a promising treatment that might be used for phytostabilization of slightly contaminated soils.     

Biosorption of Mercury by Reed (<Emphasis Type="Italic">Phragmites australis</Emphasis>) as a Potential Clean Water Technology

Heavy metals are causing serious environmental and health problems worldwide, especially in places where mining is one of the major drivers of the country’s economy. Conventional technologies are considered expensive when providing the safe water; for this reason, new clean water technologies are needed. Biosorption has gained attention as a cost-effective system that uses biological materials to remove heavy metals from water; however, it can be noted that an efficient and proven biosorbent for several heavy metal has not been found. Reed (Phragmites australis) has demonstrated to be a potential biosorbent to remove several heavy metals because it is commonly found as heavy metal accumulator in wetlands. This study is focused on mercury (Hg) removal by using reed as biosorbent. Batch experiments were conducted and the microstructure of the biosorbent was analyzed by scanning electron microscope. The Langmuir isotherm and Freundlich isotherm model was applied for the data obtained. The pseudo-first-order and pseudo-second-order models were used to test adsorption kinetics data to investigate the mechanism of biosorption. A comparison with the performance of various adsorbents reported in literature was made. The results contribute to understand the use of Phragmites australis as potential biomass for biosorbent technology since it removed mercury (Hg) effectively in high concentrations. This study supports a variety of researches to achieve clean water technologies, and biosorption has proved to be a useful alternative to the conventional systems for the removal of heavy metal ions from aqueous solution.