In Vitro Hypoglycemic Diterpenoids from the Roots of Croton yunnanensis.

Fifteen compounds including nine new diterpenes were isolated from the roots of Croton yunnanensis. By HRESIMS, NMR, ECD data, and X-ray diffraction analysis, the new compounds were characterized as eight neo-clerodane diterpenes (compounds 1-8) and one 15,16-dinor-ent-pimarane diterpene (9). All diterpenes were assayed for their hypoglycemic activities. Compounds 1-4, 6, 7, and 10 promoted glucose uptake activity in insulin-resistant 3T3-L1 adipocytes. Compounds 1 and 6 showed insulin sensitizing activity, potentiating conspicuously their glucose uptake activity at a concentration of 20 µM when treated synergistically with low-concentration insulin at 1 nM.

Tigliane Diterpenoids with Larvicidal, Antifungal, and α-Glucosidase Inhibitory Activities from Croton damayeshu.

Thirty-five tigliane diterpenoids and two ent-kaurane diterpenoids were isolated from the leaves of Croton damayeshu, and, among them, compounds 1-10 were characterized as new tigliane diterpenoids. The structures of compounds 1-10 were determined by analysis of their HRESIMS, NMR, and ECD data and by chemical methods. The isolates were assayed for their larvicidal, antifungal, and α-glucosidase inhibitory activities, and compounds 8-10 were found to possess larvicidal activities against Plutella xylostella with LC50 values of 0.19, 0.16, and 0.26 µM, respectively, comparable to the LC50 of 0.14 µM for the positive control, flubendiamide.

[China's rice field greenhouse gas emission under climate change based on DNDC model simulation].

In contrast to a large body of literature assessing the impact of agriculture greenhouse gas (GHG) emissions on climate change, there is a lack of research examining the impact of climate change on agricultural GHG emissions. This study employed the DNDC v9.5, a state-of-art biogeochemical model, to simulate greenhouse gas emissions in China' s rice-growing fields during 1971-2010. The results showed that owing to temperature rising (on average 0.49 °C higher in the second 20 years than in the first 20 year) and precipitation increase (11 mm more in the second 20 years than in the first 20 years) during the rice growing season, CH4 and N2O emissions in paddy field increased by 0.25 kg C . hm-2 and 0.25 kg N . hm-2, respectively. The rising temperature accelerated CH4 emission and N2O emission increased with precipitation. These results indicated that climate change exerted impact on the mechanism of GHG emissions in paddy field.

Purification and characterization of recombinant envelope protein GP5 of porcine reproductive and respiratory syndrome virus from E. coli.

The major envelope protein, GP5, in porcine reproductive and respiratory syndrome virus (PRRSV) plays critical roles in the assembly, invasion and immune response of PRRSV particle, and is one of the mostly studied candidates in the development of recombinant vaccines. In this research, a purification process including immobilized metal affinity chromatography (IMAC) and hydrophobic interaction chromatography (HIC) was developed to prepare recombinant envelope protein GP5 with His-tag from an E. coli strain transformed with pGEM-ORF5. The result of cell culture indicated that His-tagged GP5 protein was expressed mainly in soluble form. After cell disruption, His-tagged GP5 protein was successfully purified by Ni(2+)-chelating Sepharose Fast Flow with a yield and purity of 80.5% and 48%, respectively. Recombinant GP5 protein was further purified by HIC to achieve a purity of 95%. Moreover, the purified rGP5 is shown in monomeric form contrasting the dimeric or tetrameric form when purified by a CEX-HIC process directly from PRRSV virions as reported in a previous study.

[Affecting factors of plant stomatal traits variability and relevant investigation methods].

Stoma is the main routeway for water and gas exchange in terrestrial plants, playing an important role on the global water and carbon cycles. Stomatal traits, including stomatal density, stomatal shape, stomatal size, and stomatal index, are the long term adaptation result of plants to environmental factors during evolution, and sensitive to the changes of environmental factors. This paper reviewed the last 30 years research advances in the relationships between stomatal traits and environmental factors (e.g., air CO2 concentration, temperature, water, and light, etc. ) and the main relevant investigation methods, and proposed the main directions of future research in stomatal traits in context of climate change.

The effects of drying following heat shock exposure of the desert moss Syntrichia caninervis.

Desert mosses are components of biological soil crusts (BSCs) and their ecological functions make assessment and protection of these mosses a high-ranking management priority in desert regions. Drying is thought to be useful for desert mosses surviving heat shock. In this study, we investigated the role of drying by monitoring the responses of physiological characters and asexual reproduction in the typical desert moss Syntrichia caninervis. Heat significantly decreased chlorophyll content and weakened rapid recovery of photochemical activity, and increased carotenoid content and membrane permeability. Lethal temperatures significantly destroyed shoot regeneration potential. In comparison with heat alone, drying significantly increased protonema emergence time and depressed protonema emergence area. Drying combined with heat accelerated water loss, followed by a decrease of photosynthetic activity. Drying had different influences on membrane permeability at different temperatures. When moss leaves were subjected to a combined stress of drying and heat shock, photosynthesis was maintained mainly due to the effects of drying on physiological activity although the cellular morphological integrity was affected. Drying caused opposing effects on moss physiological and reproductive characteristics. On the one hand, drying caused a positive synergistic effect with heat shock when the temperature was below 40 degrees C. On the other hand, drying showed antagonism with heat shock when the moss was subjected to temperatures higher than 40 degrees C. These findings may help in understanding the survival mechanism of dessert mosses under heat shock stress which will be helpful for the artificial reconstruction of BSCs.

[The isolating culture of neural stem cells from rat's fetus brain and transfection by electroporation].

OBJECTIVE: To isolate and culture the neural stem cells (NSC) from rat's fetus brain, to study the transfection efficacy of NSC using electroporation. METHODS: We isolated, cultured and amplified NSC from the brain of SD fetal rats. NSC and differentiated cells were identified using immunofluorescent histochemical methods. Using green fluorescence protein (GFP) as the marker, pEGFP-N1 was transfected into NSC using electroporation, and the transfection rate was calculated by counting the NSCs with green fluorescent. RESULTS: The cells isolated from brain tissue of fetal rats can proliferate for long time, both primary and passage culture of NSC can express specific antigen of NSC-Nestin, and after induced differentiation, the cells can express specific antigen of astrocytes-Glial fibrillary acidic protein (GFAP) and specific antigen of neurons-Neuron-specific enolase (NSE). The transfection rates of electroporation were 17.9% - 69.1%, the average was 30.5%. CONCLUSION: Isolated NSC which had the features of self-proliferation and differentiation potential from brain tissue of SD fetal rats, confirmed that electroporation was an efficient transfection method for NSC, provided experimental basis for gene therapy in the future.

An estimate on the rainout of atmospheric CO2.

The CO2 in the atmosphere is in contact with water vapor and rain droplets forming CO2 x H2O, HCO3- and CO3(2-) . Global precipitation is about 505 x 1015 kg/a. Based on theoretical calculation for unpolluted air and measurement observations, we estimated that 100-270 x 10(12) gC/a are scavenged from the air by global precipitation. This roughly equals carbon emissions from volcanic sources or 2-6 per cent of current CO2 emissions. An inventory-based estimate on carbon removal in northwestern Europe supports the above calculation on global scale. With increasing CO2 concentration in the air, precipitation scavenging may increase.

Ultrastructural damage to the preserved lung and its function after reperfusion.

OBJECTIVE: This study was undertaken to clarify what damage to a lung during cold storage influenced the function of transplanted lung after reperfusion. METHODS: We examined the ultrastructural damage in preserved right lung before reperfusion, and the function of transplanted left lung, in a same dog and measured the pulmonary artery oxygen pressure after reperfusion and the wet-to-dry-weight ratio. We compared these findings between those dogs that survived until six hours after reperfusion (Alive Group) and those dogs that did not survive (Dead Group). We also investigated any correlation between the ultrastructural damage in the preserved lung and the function of the transplanted lung. RESULTS: The frequency of protrusion and destruction of the endothelial cells in the small pulmonary artery, and vacuolization of pneumocytes, in the Dead Group was significantly higher than that in the Alive Group. A correlation was found between the frequency of two kinds of ultrastructural damage; vacuolization in the endothelial cells in the small pulmonary artery and vacuolization in the pneumocytes, and the pulmonary artery oxygen pressure at 1-hour after reperfusion. A correlation was also found between the frequency of the vacuolization of pneumocytes and the wet-to-dry-weight ratio. CONCLUSIONS: Findings suggested that a lung suffering severe damage to intracellular structure during hypothermic preservation is unable to function sufficiently after reperfusion and is at high risk for early graft failure.