Analysis of multitemperature isothermal titration calorimetry data at very low c: Global beats van't Hoff

Isothermal titration calorimetry data for very low c (≡K[M]₀) must normally be analyzed with the stoichiometry parameter n fixed — at its known value or at any reasonable value if the system is not well characterized. In the latter case, ΔH° (and hence n) can be estimated from the T-dependence of the binding constant K, using the van't Hoff (vH) relation. An alternative is global or simultaneous fitting of data at multiple temperatures. In this Note, global analysis of low-c data at two temperatures is shown to estimate ΔH° and n with double the precision of the vH method.     

Sexual size dimorphism and Rensch's rule in Canidae

The size variation between males and females of a species is a phenomenon known as sexual size dimorphism (SSD). The observed patterns of variation in SSD among species has led to the formulation of Rensch's rule, which establishes that, in species showing a male size bias, SSD increases with an increase in the body size of the species. However, for species in which there is a female size bias, the SSD would decrease when the body size of the species increases. In the present study, we examined the variation in body size and SSD of 33 species of canids from estimates of body mass and body length. We studied its relationship with life‐history characteristics and tested Rensch's rule using phylogenetic generalized least squares and phylogenetic reduced major axis regressions, respectively. We observed the existence of correlation between body mass and body length, although the SSDs from these estimators are uncorrelated. SSD did not show the pattern predicted by Rensch's rule. SSD also did not show any correlation with life‐history traits. It is likely that the low SSD observed in canids is related to the monogamy observed in the family, which is a rare situation in mammals.     

Translating niche features: Modelling differential exposure of Argentine reptiles to global climate change

Global climate change affects the distributions of ectotherms and may be the cause of several conservation problems, such as great displacement of climatic suitable spaces for species and, consequently, important reductions of the extent of liveable places, threatening the existence of many of them. Species exposure (and hence vulnerability) to global climate change is linked to features of their climatic niches (such as the relative position of the inhabited localities of each species in the climatic space), and therefore to characteristics of their geographic ranges (such as the extent of the distributions or altitudinal range inhabited by the species). In order to analyze the pattern of response of Argentine reptiles to global climate change, we ran phylogenetic generalized least squares models using species exposure to global climate change as a response variable, and (i) niche properties (breadth and position of the species in the climate space) and (ii) general features of the distribution of species (maximum latitude, altitudinal range, maximum elevation, distributional range and proximity to the most important dispersal barrier) as predictors. Our results suggest that the best way to explain climate change exposure is by combining breadth and position of climatic niche of the species or combining geographic features that are indicators of both niche characteristics. Our best model shows that in our study area, species with the narrowest distributional ranges that also inhabit the highest elevations are the most exposed to the effects of global climate change. In this sense, reptile species from Yungas, Puna and Andes ecoregions could be especially vulnerable to the effects of climate change. We believe that these types of models may represent an interesting tool for determining species and places particularly threatened by the effects of global climate change, which should be strongly considered in conservation planning.     

Optimizing the spectrofluorimetric determination of cefdinir through a Taguchi experimental design approach

The aim of this work is to optimize a spectrofluorimetric method for the determination of cefdinir (CFN) using the Taguchi method. The proposed method is based on the oxidative coupling reaction of CFN and cerium(IV) sulfate. The quenching effect of CFN on the fluorescence of the produced cerous ions is measured at an emission wavelength (λ_em) of 358 nm after excitation (λ_ex) at 301 nm. The Taguchi orthogonal array L₉ (3⁴) was designed to determine the optimum reaction conditions. The results were analyzed using the signal‐to‐noise (S/N) ratio and analysis of variance (ANOVA). The optimal experimental conditions obtained from this study were 1 mL of 0.2% MBTH, 0.4 mL of 0.25% Ce(IV), a reaction time of 10 min and methanol as the diluting solvent. The calibration plot displayed a good linear relationship over a range of 0.5–10.0 µg/mL. The proposed method was successfully applied to the determination of CFN in bulk powder and pharmaceutical dosage forms. The results are in good agreement with those obtained using the comparison method. Finally, the Taguchi method provided a systematic and efficient methodology for this optimization, with considerably less effort than would be required for other optimizations techniques. Copyright © 2015 John Wiley & Sons, Ltd.     

The Combined Effect of Cu,Zn and Pb on Enzyme Activities in Soil from the Vicinity of a Wellhead Protection Area

Heavy metals are known to have adverse effects on soil ecosystems, while soil enzyme activities are sensitive to soil pollution. This study investigated the combined effects of Cu, Zn and Pb on the activities of invertase (IN), urease (U) and alkaline phosphatase (ALP) in soil obtained from the vicinity of a wellhead protection area via an orthogonal array (OA) design method. The experimental results showed the following: (1) Cu showed higher inhibition on the activities of all three enzymes than Zn and Pb when three metals were all present in the soil sample. IN activity, U activity and ALP activity decreased as the levels of Cu increased, and ranged from 15.9% to 55.7%, 3.57% to 78.6%, and 3.23% to 75.3%, respectively. Their lowest values were found in samples at 35 days with 400 mg/kg Cu. (2) Zn and Pb had different influences on the activities of the three enzymes. The lowest IN activity (the highest reduction 58.0%) and U activity (76.8%) were observed when Zn was at the concentration of 100 mg/kg after 35 days, whereas the highest inhibitory function of Zn on ALP activity (75.3%) was at 300 mg/kg after 7 days. When the concentration of Pb increased from 35 to 350 mg/kg, the activities of IN (62.5%) and U (69.6%) were most inhibited at 35 days and 14 days, respectively. However, when Pb was at the concentration of 500 mg/kg after 14 days, ALP activity (72.0%) showed the lowest value. (3) With respect to the three hydrolases in this study, ALP was the most sensitive to the two-variable interactive effects of Cu, Zn and Pb, especially Cu?×?Pb. It is concluded that the soil ALP activity may be a sensitive tool for assessing additive toxic effect on soil biochemical parameters. To provide more information about the potential ecological risk of chemicals on soil ecosystems, much more should be done to clearly determine the mechanisms of the combined effects of heavy metals in soil.     

氨基酸的冷电弧-光催化-吸附脱色工艺优化

将TiO2光催化剂负载于活性炭,然后将活性炭装填于冷电弧-光催化-吸附集成反应器中,用该反应器对豆粕氨基酸进行脱色。以豆粕氨基酸的脱色率和氨基酸保留率为指标,探讨处理电压、处理时间、溶液pH和活性炭填充量4个因素对脱色效果的影响。在单因素试验的基础上,利用二次回归正交旋转组合设计建立回归模型方程确定最佳工艺条件,并对方程进行回归分析和系数检验。结果表明:回归方程在#=0.01水平上高度显著。各因素对脱色效果的影响程度大小依次为:溶液pH>活性炭填充量>处理时间>处理电压。最佳脱色条件为处理电压20kV、处理时间11min、溶液pH 3.6和活性炭填充量63g,此条件下氨基酸溶液脱色率为94.8%,保留率为83.1%。     

正交-满意度函数优化灵芝多糖及三萜共提取条件及其清除自由基活性

灵芝Ganoderma lingzhi是我国的一种著名珍稀药用真菌,多糖及三萜类化合物是其主要活性成分提。取乙时醇间水4h溶和液料为液提比取1:剂40,,以多灵糖芝和多三糖萜及的三提萜取提率取分率别为达响到应1值.13,=%正?和交k0-.4满6意%。度优函化数条优件化下乙提醇取含的量多、糖提和取三温萜,前者DPPH自由基清除活性高于热水法提取多糖,后者与乙醇浸提法提取三萜有相近的DPPH自由基清除活性。     

脆木耳生物学特性及驯化栽培

对采自海南省白沙县鹦哥岭阔叶树腐木上的标本,根据形态学特征和多基因分析,鉴定为脆木耳Auricularia fibrillifera,经分离纯化获得纯菌株作为实验材料,为了充分利用和开发木耳属资源,首次对该种的生物学特性和驯化栽培进行了研究。研究不同碳源、氮源、无机盐和生长因子在固体培养条件下对脆木耳菌丝生长的影响,对以上4个因素进行单因素试验,从中选出3个最优的水平进行正交试验。结果表明：脆木耳菌丝最适生长温度为33℃,最佳碳源为麦芽糖,最佳氮源为牛肉粉,最佳无机盐添加量为1.5% PO₄^3--1% Mg²⁺,最佳生长因子为玉米汁。驯化栽培过程中,栽培配方为：木屑78%,麸皮20%,石膏粉1%,石灰粉1%,发菌温度为22℃可使脆木耳菌丝在40d左右满袋,且生长旺盛,可培育出子实体。     

A metabolome‐based core hybridisation strategy for the prediction of rice grain weight across environments

Marker‐based prediction holds great promise for improving current plant and animal breeding efficiencies. However, the predictabilities of complex traits are always severely affected by negative factors, including distant relatedness, environmental discrepancies, unknown population structures, and indeterminate numbers of predictive variables. In this study, we utilised two independent F₁ hybrid populations in the years 2012 and 2015 to predict rice thousand grain weight (TGW) using parental untargeted metabolite profiles with a partial least squares regression method. A stable predictive model for TGW was built based on hybrids from the population in 2012 (r = 0.75) but failed to properly predict TGW for hybrids from the population in 2015 (r = 0.27). After integrating hybrids from both populations into the training set, the TGW of hybrids could be predicted but was largely dependent on population structures. Then, core hybrids from each population were determined by principal component analysis and the TGW of hybrids in both environments were successfully predicted (r > 0.60). Moreover, adjusting the population structures and numbers of predictive analytes increased TGW predictability for hybrids in 2015 (r = 0.72). Our study demonstrates that the TGW of F₁ hybrids across environments can be accurately predicted based on parental untargeted metabolite profiles with a core hybridisation strategy in rice. Metabolic biomarkers identified from early developmental stage tissues, which are grown under experimental conditions, may represent a workable approach towards the robust prediction of major agronomic traits for climate‐adaptive varieties.