第二松花江中下游汞污染对鱼类影响的研究

五十年代,日本发现了震惊世界的水俣病(原田正纯,1975),受到了有关国家政府和学术界的关注。这种病主要是食含甲基汞的鱼引起的(上田喜一,1974;武内忠男,1973)。我国第二松花江中下游自1958年以来,汞污染逐渐严量。仅吉林化学工业公司所属厂的四个车间,历年累计排汞量就高达一百余吨(除大量无机汞外,还含有甲基汞和其     

Nucleotide binding affinities of the intact proton-translocating transhydrogenase from Escherichia coli

Transhydrogenase (E.C. 1.6.1.1) couples the redox reaction between NAD(H) and NADP(H) to the transport of protons across a membrane. The enzyme is composed of three components. The dI and dIII components, which house the binding site for NAD(H) and NADP(H), respectively, are peripheral to the membrane, and dII spans the membrane. We have estimated dissociation constants (K_d values) for NADPH (0.87 μM), NADP⁺ (16 μM), NADH (50 μM), and NAD⁺ (100-500 μM) for intact, detergent-dispersed transhydrogenase from Escherichia coli using micro-calorimetry. This is the first complete set of dissociation constants of the physiological nucleotides for any intact transhydrogenase. The K_d values for NAD⁺ and NADH are similar to those previously reported with isolated dI, but the K_d values for NADP⁺ and NADPH are much larger than those previously reported with isolated dIII. There is negative co-operativity between the binding sites of the intact, detergent-dispersed transhydrogenase when both nucleotides are reduced or both are oxidised.     

维甲酸结合蛋白的分子可及性与该蛋白和配体相互作用的关系的研究

从蛋白质可及性分析的角度研究了ＥＲＡＢＰ与ＲＡ的相互作用模式,在原子水平和残基水平上计算了四个与维甲酸结合蛋白（ＥＲＡＢＰ）有关的分子的可及性,这四个分子是ＥＰＡ（无配体结晶生成的ＥＲＡＢＰ）,ＥＰＢ—ＲＡ（ＥＲＡＢ和配体雏甲酸ＲＡ,并对其进行分析比较。分析结果表明,ＲＡ在结合蛋白中采取β－芷香酮环向里,羧基端向外的构象形式;围绕结合部位有２４个残基;在结合配体ＲＡ时,在结合配体ＲＡ时,结合蛋白将发生构象变化,变化的结果是结合部位空穴的暴露程度增大。     

基于条件价值法的大熊猫(Ailuropoda melanoleuca)存在价值评估

大熊猫(Ailuropoda melanoleuca)是我国特有的国家一级保护物种,具有重要的保护意义,但其存在价值目前缺乏明确的市场价格.因此对大熊猫的存在价值进行估算,在中国乃至世界的野生动物保护中具有重要作用.通过条件价值法(contingent valuation method, CVM),研究了我国居民对于大熊猫的保护意识和支付意愿(willingness to pay, WTP),进而对大熊猫总体存在价值进行了评估.问卷调查选择在大熊猫栖息地集中分布的四川省进行,采用支付卡式(Payment Card, PC)问卷调查方式,对回收的674份有效问卷进行统计分析.其中非零支付474份,占有效问卷的70.4%.调查表明:人均支付价值为82.7yuan/a,进而得出我国大熊猫总的存在价值为3.67×1010yuan/a.建立支付价值与居民社会经济因子的回归模型,通过AIC(Akaike′s Information Criterion)指数选择最优模型,结果显示对支付价值有显著影响的因子为学历、收入和年龄.其中,支付价值与学历、收入水平呈正相关,与年龄呈负相关.通过对年龄、学历、收入3个因子进行方差分析,得出各因子不同水平支付价值的差异.     

Biofortification of crops with seven mineral elements often lacking in human diets – iron, zinc, copper, calcium, magnesium, selenium and iodine

The diets of over two-thirds of the world's population lack one or more essential mineral elements. This can be remedied through dietary diversification, mineral supplementation, food fortification, or increasing the concentrations and/or bioavailability of mineral elements in produce (biofortification). This article reviews aspects of soil science, plant physiology and genetics underpinning crop biofortification strategies, as well as agronomic and genetic approaches currently taken to biofortify food crops with the mineral elements most commonly lacking in human diets: iron (Fe), zinc (Zn), copper (Cu), calcium (Ca), magnesium (Mg), iodine (I) and selenium (Se). Two complementary approaches have been successfully adopted to increase the concentrations of bioavailable mineral elements in food crops. First, agronomic approaches optimizing the application of mineral fertilizers and/or improving the solubilization and mobilization of mineral elements in the soil have been implemented. Secondly, crops have been developed with: increased abilities to acquire mineral elements and accumulate them in edible tissues; increased concentrations of 'promoter' substances, such as ascorbate, β-carotene and cysteine-rich polypeptides which stimulate the absorption of essential mineral elements by the gut; and reduced concentrations of 'antinutrients', such as oxalate, polyphenolics or phytate, which interfere with their absorption. These approaches are addressing mineral malnutrition in humans globally.     

Environmental Supply-Chain Management in the Computer Industry:A Transaction Cost Economics Perspective

Our article uses the theory of transaction cost economics as a conceptual basis for examining the contracting mechanisms by which firms in the computer industry structure programs to encourage their suppliers to improve their environmental management systems and/or the environmental quality of their products. We explore the economic transactions hazards associated with asking suppliers to invest in the specialized technologies required to improve environmental performance of products and management practices and the relational contracting mechanisms computer industry firms are using to protect themselves against these hazards. We also describe the importance the managers we interviewed attributed to various transactions hazards and their perceptions of how well their firms were coping with them. We conclude by discussing questions for future research. By using TCE to frame our analysis of how computer manufacturers are structuring their relationships with their suppliers in the environmental area, we hope to show how social science theory can be used to enrich and increase the practicality of the work done by engineers and others in the mainstream areas of the industrial ecology field.     

Reduction of mitochondrial pyruvate dehydrogenase phosphatase activity in lactating rat mammary gland following starvation or insulin deprivation.

The initial rates of activation of inactivated pyruvate dehydrogenase from lactating rat mammary gland and from pig heart were employed to assay pyruvate dehydrogenase phosphatase activity in mammary gland mitochondrial extracts. 24 h-starvation or 3 h-deprivation of insulin diminished phosphatase activity compared to fed controls. Refeeding and insulin treatment of 24 h starved animals restored in 1 h control levels of phosphatase activity.     

Estimation of Cellobiohydrolase Ⅰ Activity by Numerical Differentiation of Dynamic Ultraviolet Spectroscopy

1,4-β-D-glucan cellobiohydrolase Ⅰ （CBH Ⅰ）, p-nitrophenyl β-D-cellobioside, p-nitrophenol and cellobiose show distinct ultraviolet spectra, allowing the design of an assay to track the dynamic process of p-nitrophenyl β-D-cellobioside hydrolysis by CBH Ⅰ. Based on the linear relationship between p-nitrophenol formation in the hydrolysate and its first derivative absorption curve of AUC340-400 m （area under the curve）, a new sensitive assay for the determination of CBH Ⅰ activity was developed. The dynamic parameters of catalysis reaction, such as Vm and kcat, can all be derived from this result. The influence of β-glucosidase and endoglucanase in crude enzyme sample on the assay was discussed in detail. This approach is useful for accurate determination of the activity of CBHs.     

Estimation of Cellobiohydrolase I Activity by Numerical Differentiation of Dynamic Ultraviolet Spectroscopy

1,4-β-D-glucan cellobiohydrolase I (CBH I),p-nitrophenyl β-D-cellobioside,p-nitrophenol andcellobiose show distinct ultraviolet spectra,allowing the design of an assay to track the dynamic process ofp-nitrophenyl β-D-cellobioside hydrolysis by CBH I.Based on the linear relationship between p-nitrophenolformation in the hydrolysate and its first derivative absorption Curve of AUC340_400_(nm)(area under the curve),a new sensitive assay for the determination of CBH I activity was developed.The dynamic parameters ofcatalysis reaction,such as Vm and k_(cat),can all be derived from this result.The influence of β-glucosidase andendoglucanase in crude enzyme sample on the assay was discussed in detail.This approach is useful foraccurate determination of the activity of CBHs.     

乙型脑炎患者脑脊液和血浆氨基酸代谢的变化

本文采用气相色谱法对５７例乙型脑炎患者极期和２１例恢复期患者的脑脊液（ＣＳＦ）和血浆１４种游离氨基酸浓度进行分析。结果表明,乙脑极期ＣＳＦ游离氨基酸浓度除苏氨酸、丝氨酸值低于正常值外,其它氨基酸值均增高,其中谷氨酸、鸟氨酸、赖氨酸、缬氨酸、脯氨酸值上升明显（ａｌｌＰ＜０．０１）,至乙脑恢复期不同幅度下降。乙脑极期血浆游离脯氨酸、赖氨酸、苯丙氨酸、酪氨酸、鸟氨酸、谷氨酸浓度高于正常值,而其它８种氨基酸值均下降明显,至乙脑恢复期,多数氨基酸恢复至接近正常水平。实验提示,乙脑病毒能明显影响血浆和ＣＳＦ中氨基酸的含量,而二者具有代谢差异。     

Impact of Firm-Based Environmental Standards on Subsidiaries and Their Suppliers: Evidence from Motorola-Penang

How successful are multinational corporations in extending their firm-based environmental standards to their subsidiaries and those subsidiaries' local suppliers in their global production networks in developing countries? We address this question through an in-depth case study of how Motorola, a prominent multinational electronics firm with an extensive global production network, is using a set of firm-based standards to meet several new stringent European Union environmental directives. The case study demonstrates that these firm-based standards appear to be enabling a major subsidiary and its suppliers in one developing economy to reduce the environmental intensities of their production activities. This finding suggests that the firm-based environmental standards of multinationals with extensive global production networks might contribute to a leveling up of environmental standards in subsidiaries and their local suppliers, rather than a "race to the bottom", thus reinforcing the technique or intensity effects associated with open trade, investment, and technology policies.     

Calculation of a Toxic Potential Indicator Via Chinese-Language Material Safety Data Sheets

This article presents an approach to evaluating the toxic potential for products or materials using Chinese-language material safety data sheets (MSDSs). The toxic potential indicator (TPI) is one of many simple methods used to evaluate the environmental impact of toxins in products and materials. According to actual application experience in Taiwan, difficulties and problems arise in the preliminary implementation of TPI values calculated via Chinese-language MSDSs. Some adjustment techniques combining Chinese vocabulary conversion and unit transformation are proposed in this article to overcome these obstacles. The proposed procedures and evaluated results can serve as a basis for environmentally conscious product design, especially with regard to the choice of materials used in Chinese-speaking countries.     

羟基磷灰石／聚乳酸及其共聚物复合生物材料

阐述了羟基磷灰石、聚乳酸和聚乙醇酸各自的结构性能特点;总结了两者通过复合有望得到具有良好力学性能、生物相容性、骨传导性的可降解羟基磷灰石／聚乳酸复合生物材料;最后展望了这类复合生物材料的发展方向。     

Identification of specific binding sites for leukotriene C4 in human fetal lung

Specific leukotriene C₄ (LTC₄) binding sites were identified in membrane preparations from human fetal lung. Specific binding of [³H]-LTC₄ represented 95 percent of total binding, reached steadystate within 10 minutes and was rapidly reversible upon addition of excess unlabeled LTC₄. Binding assays were performed at 4°C under conditions which prevented metabolism of [³H]-LTC₄ (80 mM serineborate, 10 mM cysteine, 10 mM glycine). Under these conditions, greater than 95 percent of the membrane bound radioactivity, as analyzed by high performance liquid chromatography, co-eluted with the LTC₄ standard. Computer-assisted analyses of saturation binding data showed a single class of binding sites with a dissociation constant (K_d) of 26 + 6 nM and a density (B_max) of 84 ± 18 pmol/mg protein. Pharmacological specificity was demonstrated by competition studies in which specific binding of [³H]-LTC₄ was displaced by LTC₄ and its structural analogs with inhibition constants (K_j) of 10 to 30 nM, whereas LTD₄, diastereoisomers of LTD₁, LTE₄ and the end organ antagonist FPL 55712 were 150 to 700 fold less potent competitors than LTC₄. These results provide evidence for specific, reversible, saturable, high affinity binding sites for [³H]-LTC₄ in human fetal lung membranes.     

骨嗜酸性肉芽肿放射治疗临床分析

目的：探讨骨嗜酸性肉芽肿的治疗方法。方法：对近5年来我院收治经病理证实的12例骨嗜酸性肉芽肿的治疗进行临床回顾性研究。结果：随访1．5a～6a,其中11例患者行局部肿块刮除和放射治疗30Cy后治愈,1例复发,行再程治疗后治愈,总有效率为100％。结论：骨嗜酸性内芽肿治疗采用手术局部肿块刮除和放射治疗,可取得良好效果。     

我国现有的金鱼品种的分类及其系统发育的探讨1)

一、引言 金鱼是我国广大人民乐于饲养的一种家养观赏鱼类。它是由野生红黄色鲫鱼演变而来的。明朝李时珍在《本草纲目》中记载:金鱼“述异记载晋桓冲游庐山,见湖中有赤鳞鱼,即此也。”他还写道:“自宋始有畜者,今则处处家养玩矣。”因此可以认为金鱼起源于我国晋朝(公元265—420年间)。至今已有一千多年的历史了。 李璞(1959)报道了我国的金鱼品种已有二十余个。徐金声等(1980)报道有143个之多。耶么迄今为止我国的金鱼品种究竟有多少呢?为了弄清我国的金鱼品种资源,作者曾在北京等十七个省市的各大公园和花木公司所属鱼场作了调查。在调查过程中,我们     

转铁蛋白受体单链抗体与BDNF融合蛋白的表达及活性鉴定

脑源性神经营养因子（BDNF）对中枢神经系统的多种神经元具有营养,修复和保护功能,但因无法通过血脑屏障限制了其应用。本文利用抗转铁蛋白受体（TfR）的单链抗体（ox26-scFv）作为脑转运载体,分别扩增单链抗体和BDNF基因,插入pTIG-Trx载体,构建融合基因表达载体pTIG-Trx/scFv-BDNF,在大肠杆菌BL21（DE3）中实现了高效表达。经Ni-NTA金属鏊合层析柱纯化后,在41Kd处可见目的纯化条带。大鼠GH3细胞免疫酶染色显示,ScFv-BDNF融合蛋白能与转铁蛋白受体特异性结合。同时能够促进鸡胚背根节神经突起的生长,具备了BDNF的生物学活性。为使BDNF能够跨越血脑屏障成为中枢神经系统的治疗药物打下了实验基础。