Effects of Bioavailable Heavy Metal Species,Arsenic, and Acid Drainage from Mine Tailings on a Microbial Community Sampled Along a Pollution Gradient in a Freshwater Ecosystem

Sediment and water samples representing a pollution gradient in a long, narrow lake polluted at one end by heavy metals, arsenic, and acid drainage from mine tailings, together with samples from an unpolluted reference lake, were analyzed to determine effects of pollutants on the microbial community of the polluted lake. Ribosomal ribonucleic acid, fatty acid, and phospholipid analyses, along with assays of CO₂ production, denitrification, and enzyme activities, were performed to characterize the microflora; and environmental conditions were defined by various physicochemical analyses, including determination of bioavailable metal species. Mine waste pollution fostered the growth of Holophagal Acidobacteria, green sulphur bacteria, and α-Proteobacteria but inhibited numerous other types of microorganisms, reducing the overall productivity, biomass, and biodiversity of the microflora. The beneficial effects imply toleration of pollutants, suppression of competing or antagonistic species, and utilization of biogenic sulphide; and the toxic effects are attributable to bioavailable metals, arsenic, and sulphuric acid produced by oxidation of sulphides. The bioavailability and toxicity of sediment-bound metals were evidently increased by acidification, elevation of sediment Eh, and inhibition of metal-immobilizing bacteria by pollutants but were decreased by metal-scavenging oxyhydroxides, sulphide, and organic matter. Metal toxicity also depended on specific metal properties (e.g., electronegativity), providing a basis for inferring mechanisms of toxicity and oxidation states of metals and explaining differences in relative toxicity. The pollutants harmed the ecosystem as a whole by inhibiting microorganisms that performed crucial ecological functions, notably oxygen-releasing photosynthesis, decomposition and humification of organic matter, nutrient recycling, and control of metal availability.     

Amperometric detection of cholesterol using an indirect electrochemical oxidation method

The indirect electrochemical oxidation method using bromine species in an organic media for measuring cholesterol was developed. The electrochemical behaviors of cholesterol were examined by cyclic voltammetry in a potential range of −0.5 to 2.0 V (vs. Ag/AgCl/saturated KCl). The polarization curve of the steady-state current in the applied potential range of 0-2.0 V is reported. The obtained kinetic parameters for the catalytic oxidation of cholesterol support the assumption that positive bromine species can be generated from bromine by undergoing two consecutive electrochemical oxidation steps. The positive bromine acts both as electron mediators and as electrocatalysts. Amperometric detection with an anodic current was investigated, and the calibration curve exhibited a linear relationship between the steady-state current and the concentration of cholesterol in the range of 30-200 μM, from which the sensitivity was calculated to be about 0.2 μA/cm²/μM. Moreover, the amperometric current followed Michaelis-Menten’s enzymatic model for cholesterol concentrations in the range of 30 μM to 5 mM, which can be applied for cholesterol rapid detection in processed foods.     

Changes of China agricultural climate resources under the background of climate change: IX. Spatiotemporal change characteristics of China agricultural climate resources

Based on the 1961-2007 ground surface meteorological data from 558 meteorological stations in China, this paper analyzed the differences of agricultural climate resources in China different regions, and compared the change characteristics of the agricultural climate resources in 1961-1980 (period I) and 1981-2007 (period II), taking the year 1981 as the time node. As compared with period I, the mean annual temperature in China in period II increased by 0.6 degrees C, and the > or = 0 degrees C active accumulated temperature in the growth periods of chimonophilous crops and the > or = 10 degrees C active accumulated temperature in the growth periods of thermophilic crops increased averagely by 123.3 degrees C x d and 125.9 degrees C x d, respectively. In 1961-2007, the mean annual temperature increased most in Northeast China, and the > or = 10 degrees C active accumulated temperature in the growth periods of thermophilic crops increased most in South China. The whole year sunshine hours and the sunshine hours in the growth periods of chimonophilous crops and of thermophilic crops in period II decreased by 125.7 h, 32.2 h, and 53.6 h, respectively, compared with those in period I. In 1961-2007, the annual sunshine hours decreased most in the middle and lower reaches of Yangtze River, while the sunshine hours in the growth periods of chimonophilous crops and of thermophilic crops decreased most in North China and South China, respectively. In the whole year and in the growth periods of chimonophilous and thermophilic crops, both the precipitation and the reference crop evapotranspiration in this country all showed a decreasing trend, with the largest decrement in the precipitation in the whole year and in the growth periods of chimonophilous and thermophilic crops in North China, the largest decrement in the reference crop evapotranspiration in the whole year and in the growth periods of thermophilic crops in the middle and lower reaches of Yangtze River, and the largest decrement in the reference crop evapotranspiration in the growth periods of chimonophilous crops in Northwest China. In 1961-2007, the climate in China in the whole year and in the growth periods of thermophilic crops showed an overall tendency of warm and dry, and the climate in the growth periods of thermophilic crops became warm and dry in Southwest China, North China, and Northeast China, but warm and wet in the middle and lower reaches of Yangtze River, Northwest China, and South China, whereas the climate in the growth periods of chimonophilous crops became warm and dry in North China, but became warm and wet in Northwest China.     

气候变化背景下中国农业气候资源变化Ⅱ.西南地区农业气候资源时空变化特征

基于1961—2007年中国西南地区88个气象台站的地面观测资料,结合统计方法和GIS软件,分析了全年及温度生长期内农业气候资源的时空变化特征.结果表明:1961—2007年,西南地区年平均气温呈上升趋势,平均增速为0.18℃.(10 a)-1;温度生长期内≥10℃和≥15℃积温均呈增加趋势,平均增速分别为55.3℃.d.(10 a)-1和37℃.d.(10a)-1.全区年日照时数呈现由西向东逐渐减少的特征,且东部的减少趋势较西部更显著;温度生长期内日照时数整体呈增加趋势,但空间差异较大.全区降水资源总体减少,年降水量和温度生长期内降水量的平均下降速率分别为10 mm.(10 a)-1和8 mm.(10 a)-1.全区年参考作物蒸散量普遍降低,其减幅小于年降水量的变化趋势,约53%的站点温度生长期内参考作物蒸散量减少.     

Macro‐scale bird species richness patterns of the East Asian mainland and islands: energy,area and isolation

Aim To create a map of bird species richness (BSR) in East Asia and to examine the effect of area, isolation, primary productivity, topographic heterogeneity, and human population density on BSR. Location East Asia (from 70° E to 180° E longitude), including the eastern half of the Palaearctic Region, the entire Oriental Region, and the entire Wallacea Subregion. Methods The breeding ranges of 2406 terrestrial bird species were mapped and overlaid to create a species richness map. The BSR map was transformed into a 100 × 100 km quadrat system, and BSR was analysed in relation to land area, average normalized difference vegetation index (NDVI), elevation range, and average population density. Results In general, BSR declined from the Tropics to the Arctic. In mainland East Asia, however, BSR was highest around the Tropic of Cancer, and fluctuated between 30° and 50° N. Islands had lower BSR than adjacent mainland areas. The NDVI was strongly positively correlated with BSR in mainland areas and on islands. For mainland areas, NDVI explained 65% of the BSR variation, and topographic heterogeneity explained an additional 6% in ordinary least‐squares regression. On islands, NDVI explained 66% of BSR variation, island area explained 13%, and distance to mainland accounted for 1%. Main conclusions In East Asia, we suggest that primary productivity is the key factor underpinning patterns of BSR. Primary productivity sets the upper limits of the capacity of habitats to support bird species. In isolated areas such as islands and peninsulas, however, BSR might not reach the richness limits set by primary productivity because the degree of isolation and area size also can affect species richness. Other factors, such as spatial heterogeneity, biotic interactions, and perturbations, may also affect species richness. However, their effects are secondary and are not as strong as primary productivity, isolation, and area size.     

Studies of H4R antagonists using 3D-QSAR,molecular docking and molecular dynamics

Three-dimensional quantitative structure–activity relationship studies were performed on a series of 88 histamine receptor 4 (H4R) antagonists in an attempt to elucidate the 3D structural features required for activity. Several in silico modeling approaches, including comparative molecular field analysis (CoMFA), comparative similarity indices analysis (CoMSIA), molecular docking, and molecular dynamics (MD), were carried out. The results show that both the ligand-based CoMFA model (Q ² = 0.548, R _ncv² = 0.870, R _pre² = 0.879, SEE = 0.410, SEP = 0.386) and the CoMSIA model (Q ² = 0.526, R _ncv² =0.866, R _pre² = 0.848, SEE = 0.416, SEP = 0.413) are acceptable, as they show good predictive capabilities. Furthermore, a combined analysis incorporating CoMFA, CoMSIA contour maps and MD results shows that (1) compounds with bulky or hydrophobic substituents at positions 4–6 in ring A (R2 substituent), positively charged or hydrogen-bonding (HB) donor groups in the R1 substituent, and hydrophilic or HB acceptor groups in ring C show enhanced biological activities, and (2) the key amino acids in the binding pocket are TRP67, LEU71, ASP94, TYR95, PHE263 and GLN266. To our best knowledge, this work is the first to report the 3D-QSAR modeling of these H4R antagonists. The conclusions of this work may lead to a better understanding of the mechanism of antagonism and aid in the design of new, more potent H4R antagonists.     

Glutathione s-transferase m1 gene polymorphism and laryngeal cancer risk: a meta-analysis

Background and Objectives

Studies investigating the association between glutathione S-transferase M1 (GSTM1) gene polymorphism and laryngeal cancer risk have reported conflicting results. The aim of the present study was to conduct a meta-analysis assessing the possible associations of GSTM1 gene polymorphism with laryngeal cancer risk.

Methods

The relevant studies were identified through a search of PubMed, Embase, ISI Web of Knowledge and Chinese National Knowledge Infrastructure until May 2011 and selected on the basis of the established inclusion criteria for publications, then a meta-analysis was performed to quantitatively summarize association of GSTM1 polymorphism with laryngeal cancer susceptibility.

Results

Seventeen studies were included in the present meta-analysis (2,180 cases and 2,868 controls). The combined results based on all studies showed that GSTM1 null genotype was associated with increased laryngeal cancer risk (OR = 1.17, 95% CI = 1.04∼1.31). When stratifying for race, GSTM1 null genotype exhibited increased laryngeal cancer risk in Caucasians (OR = 1.15, 95% CI = 1.01∼1.31), while no significant association was detected in Asians (OR = 1.25, 95% CI = 0.80∼1.96). In the subgroup analysis based on source of controls, significant associations were observed in the population-based studies (OR = 1.15, 95% CI = 1.01∼1.31) yet not in the hospital-based studies (OR = 1.25, 95% CI = 0.93∼1.67). Furthermore, in the subgroup analysis based on sample size, significant associations were also found in studies with at least 50 cases and 50 controls (OR = 1.15, 95% CI = 1.02∼1.30) but not in studies with fewer than 50 cases or 50 controls (OR = 1.46, 95% CI = 0.87∼2.46).

Conclusions

This meta-analysis supported that the GSTM1 gene polymorphism was associated with laryngeal cancer, particularly in Caucasians, and these associations varied in different subgroup, which indicated that population-based study with larger sample size was more appropriate in design of future study.     

Pyrazoloquinolines as PDE10A inhibitors: discovery of a tool compound

A series of pyrazoloquinolines, possessing (hetero)arylhydroxymethyl substituents at the quinoline C-4 position were evaluated as PDE10A inhibitors. Among these, methylpyrimidyl analogue 15 was identified as having good rodent and monkey exposure, and a MED of 10 mg/kg in an in vivo model.     

Structure elucidation of Sch 538415, a novel acyl carrier protein synthase inhibitor from a microorganism

A novel acyl carrier protein synthase inhibitor, Sch 538415 (1), was isolated from an unidentified bacterial microbe. Structure elucidation of 1 was accomplished based on analysis of spectroscopic data including UV, MS and 2D-NMR spectra. Compound 1 exhibited inhibitory activity in the acyl carrier protein synthase (AcpS) assay with an IC(50) value of 4.19 microM and showed antibacterial activity against Staphylococcus aureus in the agar diffusion assay.     

Comparative regulation of major enzymes in the bile acid biosynthesis pathway by cholesterol, cholate and taurine in mice and rats

These enzymes play important roles in the biosynthesis of bile acids. They are cholesterol 7alpha-hydroxylase (CYP7A1), the rate limiting enzyme in the classic pathway, sterol 12alpha-hydroxylase (CYP8B1), the key enzyme for synthesis of cholic acid (CA), and sterol 27-hydroxylase (CYP27), the initial enzyme in the alternative pathway. In the present study, the susceptibility of these three enzymes to dietary cholesterol and cholate, and the cholesterol lowering effect of taurine were determined in male C57BL/6 mice and Wistar rats. Both mice and rats were divided into 6 groups: control group (N), high cholesterol diet group (C), high cholesterol and cholate diet group (CB), and their 1% taurine-supplemented groups (NT, CT, CBT, respectively). After animals were fed with the respective diets for one week, the mRNA levels of CYP7A1 increased in the C-group compared with those of the N-group, and decreased in the CB-group compared with those of the C-group in both mice and rats. But the extent of decrease is different between the two species. CYP8B1 was also markedly repressed by cholate in mice, but not in rats. These results are consistent with the changes in serum and liver cholesterol concentrations. Taurine significantly increased CYP7A1 mRNA levels in the CBT-group compared with the CB-group in both animal models, with a subsequent decrease in serum and liver cholesterol levels and increase in fecal bile acid excretion. Up-regulated CYP8B1 was also observed after taurine supplementation in the CBT-group in mice. No increase in CYP7A1 was produced by taurine in the CT-group compared with that of the C-group in mice, although the changes of serum and liver cholesterol and fecal bile acids indicated taurine showed an efficient cholesterol lowering effect. In addition, CYP27 was induced in both C- and CB-groups of rats but not of mice, and no changes were produced by taurine. The overall results suggest that there are differences between mice and rats in susceptibility of the three enzymes to dietary cholesterol and cholate, and taurine induced CYP7A1 to produce its cholesterol-lowering effect only in the presence of cholate in the cholesterol diet.