稳定表达犬信号淋巴细胞激活因子基因细胞株的建立与鉴定

[目的]构建稳定表达犬瘟热病毒细胞受体———犬信号淋巴细胞激活因子(SLAM)的非洲绿猴肾细胞株(Vero)。[方法]采用RT-PCR方法从犬外周血淋巴细胞中扩增出SLAM基因,将其克隆到哺乳动物真核表达载体pcDNA3.1(+)中,构建重组质粒pcDNA3.1/SLAM。采用脂质体将pcDNA3.1/SLAM转染到Vero细胞中,利用G418加压筛选和纯化培养获得稳定表达SLAM的重组Vero细胞株。应用RT-PCR和间接免疫荧光试验检测SLAM的表达。[结果]重组蛋白SLAM在Vero细胞中获得表达,并且在不同代次的阳性细胞株中均能稳定表达目的蛋白。[结论]该研究建立了稳定表达犬SLAM的细胞株Vero/SLAM,为犬瘟热病毒的分离和生物学特性研究提供了平台。     

Effect of dietary stable isotopic ratios of carbon and nitrogen on the extent of their incorporation into tissues of rats

This study was conducted to investigate the effect of different dietary ratios of 13C to 12C or 15N to 14N on their relative incorporation into tissues. Eighty male rats were used in two 21-day feeding trials in which they were fed diets with either high δ13C levels (δ13C = 13.89% and δ15N = 2.37% in experiment 1 and δ13C = 19.34% and δ15N = 4.73% in experiment 2) or low δ13C levels (δ13C = 17.90% and δ15N = 3.08% in experiment 1 and δ13C = 21.76% and δ15N = 0.53% in experiment 2), meanwhile, the dietary δ15N levels were designed to two ranks. Blood, liver, adipose and muscle tissues were collected on day 0, 3, 7, 14, and 21 for determination of 13C, 12C, 15N and 14N isotopes. Rat growth rate, antioxidant capacity and metabolic parameters were also assessed. The results indicate that adipose tissue tend to deplete 13C before the stable isotopic ratios achieved final equilibrium. Therefore, feeds with different isotopic signatures had different incorporation rates into tissues. Low dietary 13C levels decreased tissue δ13C values whereas high dietary 13C levels did not alter tissue δ13C values during the 21-d experiment. Blood δ15 N values were a reliable parameter in assessing the relative contribution of dietary nitrogen to tissues. This study revealed a relationship between dietary isotopic signatures and their incorporation rates into rat tissues. However, more studies are needed to illustrate the mechanism through which dietary isotopic ratios influence the extent of isotopic incorporation into the tissues.     

新疆5个枣品种叶片碳同位素组成、瞬时水分利用效率的季节变化及与气象因子的关系

利用稳定碳同位素技术,对新疆环塔里木盆地主栽的5个枣品种叶片δ13C值进行了比较测定,同时测定各品种的瞬时光合速率、蒸腾速率、光合有效辐射及空气温湿度等因子。结果表明,(1)新疆栽培枣品种叶片δ13C值分布在-25.559‰～-27.861‰,平均值为-26.463‰;(2)5个枣品种叶片δ13C值季节变化差异显著(P<0.05),表现为春季(-26.088‰)>夏季(-26.395‰)>秋季(-26.904‰),且品种间差异极显著,最大的为-25.559‰(骏枣春季),最小的为-27.861‰(冬枣秋季),变幅2.302‰;(3)空气相对湿度是引起δ13C值季节变化的主要因素;(4)5个枣品种长期水分利用效率(WUEsl)大小顺序为:冬枣<梨枣<灰枣<赞皇大枣<骏枣,顺时水分利用效率(WUEi)大小顺序为:冬枣<骏枣<赞皇大枣<梨枣<灰枣,2种方法测定的结果均反映出鲜食品种中冬枣对当地干旱的适应能力最弱。     

植物水分利用效率的影响因子研究综述

在概述植物水分利用效率(WUE)及其层次和测定、计算方法的基础上,介绍了影响植物WUE的内部因素(包括植物种类和品种、叶片解剖结构及生理生化特征等)和外部因素(包括气象、土壤、生物因素等),以及各自的作用机理,尤其是对气孔不均匀关闭、影响Δ13C在田间条件下表现较差的原因、冠层和叶边界层对植物WUE产生的效应及其作用原理进行了探讨,并提出了今后植物WUE研究的重点和方向。     

哈密垦区棉花区域试验品种的丰产稳产性及适应性分析

[目的]研究哈密垦区棉花区域试验品种的丰产性、稳产性及适应性,以期为育种者和推广单位提供参考。[方法]利用1年多点试验联合方差分析方法,对2011年新疆生产建设兵团农业建设第十三师组织的棉花新品种1年多点区域试验中7个品种(赣杂108、E3、A3、13-20、97H1、9-24、邯杂154)进行丰产稳产性和适应性分析,以邯杂154为对照。[结果]品种E3、A3的丰产性较好,折合皮棉产量分别为3 174.0、3 012.0 kg/hm2,较对照邯杂154分别增产15.1%、9.2%,分别居参试品种(系)第1、2位,丰产主效应值均较大,稳产参数方差和变异度均较小,为高产稳产性品种,适应性参数回归系数小,回归截距大。其余品种产量均低于对照邯杂154。[结论]E3和A3适合肥力较低条件下种植,宜大面积推广种植。     

秸秆碳对不同施肥水平低肥力土壤碳组分的影响

为探明不同施肥水平下秸秆碳对低肥力土壤溶解性有机碳（DOC）、微生物量碳（MBC）和颗粒有机碳（POC）含量的影响,采用碳化硅管原位法,向不同施肥水平（0、120、240 kg·hm^-2,以纯氮计）的低肥力土壤添加¹³C标记小麦秸秆,定期取土样测定不同有机碳组分的含量及其δ¹³C值,并计算秸秆碳在各有机碳库中的转化及贡献比例。研究结果显示,秸秆添加后7 d是快速转化阶段,此后秸秆碳转化渐缓,以向POC转化为主。相较于DOC,秸秆碳更倾向转化为MBC和POC,秸秆添加60 d后的转化比例分别为0.12%~0.38%、4.01%~6.25%和4.74%~9.54%。秸秆添加后,土壤DOC、MBC和POC含量均显著增加,来自于秸秆碳的贡献分别为0.29%~15.01%、13.20%~32.85%和33.62%~59.69%。相较于0、240 kg·hm^-2的施氮处理,施氮量为120 kg·hm^-2时,秸秆添加能同时大幅提高试验土壤的活性和缓效性有机碳库含量。由此表明,秸秆还田条件下,适量施加氮肥更有利于低肥力土壤的培肥与固碳。     

基于稳定同位素和贝叶斯模型的引黄灌区地下水硝酸盐污染源解析

地下水硝酸盐（NO₃^-）污染已经成为全球严重的水环境问题之一,由于饮用水中高含量NO₃^-会转化成亚硝酸盐而增加各种疾病和癌症风险,其来源的确定对于NO₃^-污染的预防和控制非常重要。本文以黄河下游第二大灌区——潘庄灌区为例,首次采用NO₃^-的氮氧稳定同位素结合贝叶斯模型追溯地下水NO₃^-的来源并量化各种来源的贡献比例。结果表明,地下水NO₃^-含量分布在0.1~197.0 mg·L^-1,平均值为34.2 mg·L^-1。与《生活饮用水卫生标准》中规定的地下水NO₃^-最大含量[20 mg（N）·L^-1,相当于NO₃^-含量90 mg·L^-1]相比,有10%的样品NO₃^-含量超标。井深<30 m、30~60 m和>60 m的地下水NO₃^-平均含量分别为25.9 mg·L^-1、39.7 mg·L^-1和20.1 mg·L^-1。空间上,宁津县、武城县、平原县和禹城市有大片区域地下水NO₃^-含量较高。地下水NO₃^-的δ¹⁵N组成范围为0.72‰~23.93‰,平均值为11.62‰;δ¹⁸O组成范围为0.49‰~22.50‰,平均值为8.46‰。同位素结果表明粪便和污水、农业化肥是地下水中NO₃^-的主要污染来源。这反映了人类活动是引起地下水NO₃^-污染的主要原因。贝叶斯模型结果显示,粪便和污水对潘庄灌区地下水中NO₃^-平均贡献率高达56.2%,化肥的平均贡献率为19.3%,大气降水和土壤的平均贡献率分别为6.2%和12.3%。由于污水、粪便和化肥是地下水中NO₃^-的主要来源,为保护和改善研究区地下水水质,建议加强污水管道建设,强化畜禽粪便的管理以及提高化肥利用效率。     

Effects of nitrogen supply on water‐use efficiency of higher plants

The worldwide increase of food demand and reduced sweet‐water availability in some important food‐producing regions raised interest in more efficient water use, which has become one of the central research topics in agriculture. Improved irrigation management and reduced bare‐soil evaporation have highest priority to increase agronomic water‐use efficiency (WUE). Compared to these technical (irrigation) and basic (crop production) management options, effects of nutrient management on WUE were less frequently considered. Twenty‐nine publications on nitrogen (N) effects on biomass WUE of container‐grown plants are considered in this review. Most of them indicate positive N effects on WUE, and relevance of N effects on intrinsic WUE and unproductive water and carbon loss is discussed. A plot of 90 published data of percent decreases of WUE and dry mass under variable N supply is presented. Extrapolation of biomass WUE from leaf measurements of intrinsic WUE is critically reviewed. The positive correlation between WUE and dry‐mass formation suggests that physiological rather than stomatal effects are more important in order to explain positive N effects on WUE.     

Periglacial transport distance of Pb derived from small-scale ore veins in the Rhenish Slate Mountains

The spatial extent of metal contamination caused by small-scale ore veins is increased by periglacial solifluction. Our objectives were (1) to examine the spatial distribution of Pb in cover beds that migrated over Pb ore veins, (2) to calculate the transport distance of ore-derived Pb, and (3) to determine controls on the transport distance.We examined six transects (320-775 m long) in the Rhenish Slate Mountains in West Germany. The transects included four west-exposed and two east-exposed slopes with inclinations between 2-20°. All transects were forest-covered and located at 280-450 m above sea level. Soils were Dystric Cambisols and Stagnic Luvisols. Samples of 120 B horizons developed in the sediments of the last ice age (Wuerm) were analyzed for total Pb concentrations and partly also ²⁰⁶Pb/²⁰⁷Pb ratios. The Pb concentrations ranged from 20 to 135 mg kg^− 1. The spatial Pb distribution suggested that 14 (out of 18) sampling points showing local Pb concentration maxima contained Pb from ore veins upslope. With a two-end-member-mixing model using ²⁰⁶Pb/²⁰⁷Pb isotope ratios of the ore (²⁰⁶Pb/²⁰⁷Pb ratio: 1.1828) as one end member and of the native substrate (a mixture of slate and loess; ²⁰⁶Pb/²⁰⁷Pb ratio: 1.2254 ± 0.0072) as the other we confirmed that the 14 Pb peaks originated from the ore, because they contained 76-100% of ore-derived Pb. By the use of a geographic information system, the transport distance of this Pb was determined to range between 30 and 110 m. Silt concentrations (Pearson r = − 0.69) and the relief curvature (Cramér's V = 0.60) were major controls on the transport distance. Our study demonstrates that Pb ore veins can increase native soil Pb concentrations in soil derived from the periglacial drift of the last ice age (Wuerm) up to a distance of more than 100 m.     

陕西关中地区肉牛产地同位素溯源技术初探

为应用牛组织中C、N同位素组成的区域分布和同位素指标溯源肉牛产地,本文利用同位素比率质谱仪(IRMS)对陕西关中不同区县来源的牛尾毛样品的1δ3C和1δ5N值进行检测,通过聚类分析,研究陕西关中地区肉牛组织中同位素组成的区域分布情况。结果表明,杨凌区、眉县牛尾毛样品聚为一类;乾县、永寿县样品聚为一类;麟游县样品聚为一类;扶风县、岐山县和凤翔县分类不十分明显,分散在上述3类中。说明陕西关中不同地区肉牛组织中同位素组成存在差异,利用它们可进行肉牛地域的小范围溯源。