Probing Free Radical Damage to Biological Molecules by Spin-labeling Fluorophore

A spin-labeling fluorophore(NA-TEMPO ·), formed by labeling α-naphthalene with a paramagnetic nitroxide(4-hydroxyl-2,2,6,6-tetramethylpiperidinyl-1-oxy), was explored for biologically relevant carbon-centered radicals. The horseradish peroxidase (HPR)/H 2O 2 reaction was used to generate radicals in derivatives of tyrosine and phenylalanine, and the Fenton reaction was used to generate radicals in deoxyguanosine, guanosine, bovine serum albumin(BSA) and DNA. TEMPO ·-NA, a weak fluorescent compound, showed a dramatic increase in fluorescence intensity after scavenging carbon-centered radicals. The spin-labeling fluorophore with dual function groups, the radical recognizing group and fluorescent group, would be significantly useful in monitoring the formation and translocation of carbon-centered radicals in complex biological systems.国家自然科学基金 (批准号 :2 0 3 75 0 3 2 )资

黄土塬区氮磷配施对冬小麦光合作用、产量形成及水分利用的影响

在黄土高塬沟壑区,研究了不同施肥条件对冬小麦各个生育期的叶面积指数、光合作用、干物质积累、产量形成以及水分利用的影响,结果表明:与对照相比,施肥后小麦叶面积指数和光合速率都显著提高,同化作用增强,平均产量提高了47.6%,水分利用效率提高了24.6%。不同的肥料配施对冬小麦的干物质积累、产量以及水分利用效率的影响顺序基本一致,即高氮高磷>高氮低磷>低氮低磷>低氮高磷,但方差分析表明,在这种氮磷配施方案中起作用的主要是氮肥,磷肥的贡献不大,且二者并没有产生明显的交互作用

辐射免疫学研究进展

近年来辐射免疫学作为一门新兴学科进展迅速,特别是在低剂量辐射兴奋效应研究方面有较大发展,同时重离子辐射生物效应的研究在治疗肿瘤方面也有了明显进步。综述了国内、外辐射免疫学的现况,其目的是寻找出一种综合疗法,从而达到既可以较好的治疗肿瘤,又对病人损伤较小的目的

Effect of long-term fertilization on winter wheat water utilization in rain-fed farmland of the Loess Tableland

对长期定位施肥试验第22年度的测定数据进行了分析,探讨了旱地施肥对冬小麦水分利用的影响。试验结果表明,测定年份冬小麦的耗水深度受播种前雨季降雨入渗深度的影响位于地下200 cm左右。长期单施磷肥处理,播种期土壤有效贮水量与不施肥的对照接近,而单施氮肥,氮磷配施和氮磷钾配施均显著低于对照;在施P2O590 kg/hm2配施氮肥或施N 90 kg/hm2配施磷肥,随着施氮量或施磷量从0增加到180 kg/hm2,播种期土壤有效贮水量均逐渐降低,但前者作物的土壤水分消耗表现出降低趋势,而后者表现出增加趋势。与对照相比,各施肥处理均提高了土壤有效底墒的利用率。氮磷配施比单施磷肥降低了土壤供水占作物耗水的比例,使得作物生长和产量的形成对当季降水的依赖性增加。与对照相比,氮磷配施及氮磷钾配施显著提高了冬小麦收获指数、产量和水分利用效率,而单施磷肥和氮肥使收获指数、产量和水分利用效率显著降低。施P2O590 kg/hm2的条件下,不同施氮量之间收获指数差异较小,而产量和水分利用效率均高于单施磷肥;施N 90 kg/hm2的条件下,不同施磷量作物的收获指数、产量和水分利用效率均得到提高

Probing free radical damage to biological molecules by spin-labeling fluorophore

A spin-labeling fluorophore(NA-TEMPO.), formed by labeling a-naphthalene with a paramagnetic nitroxide (4-hydroxyl-2, 2, 6, 6-tetramethylpiperidinyl-1-oxy), was explored for biologically relevant carbon-centered radicals. The horseradish peroxidase (HPR)/H2O2 reaction was used to generate radicals in derivatives of tyrosine and phenylalanine, and the Fenton reaction was used to generate radicals in deoxyguanosine, guanosine, bovine serum albumin (BSA) and DNA. TEMPO.-NA, a weak fluorescent compound, showed a dramatic increase in fluorescence intensity after scavenging carbon-centered radicals. The spin-labeling fluorophore with dual function groups, the radical recognizing group and fluorescent group, would be significantly useful in monitoring the formation and translocation of carbon-centered radicals in complex biological systems

两种不同相对分子质量的壳寡糖对小鼠免疫功能的影响

目的研究两种不同相对分子质量的壳寡糖（chitosan oligosaccharide,COS）对小鼠免疫功能的影响。方法小鼠腹腔注射壳寡糖S-COS（平均相对分子质量800）,壳寡糖B-COS（平均相对分子质量1700）,硫酸岩藻糖（Fucoidan）120mg.kg-1,每日1次,连续14d,第10天注射5%牛血清白蛋白（bovine serum albumin,BSA）200μL/只进行免疫。于第15天检测脾指数,血清中细胞因子（IL-10、TNF-α、IFN-γ）含量,脾中淋巴细胞增殖,以及脾中CD4＋T细胞增殖。结果 S-COS和B-COS都能够促进CD4＋T细胞增殖,另外,B-COS还能增加脾指数,促进细胞因子IL-10和TNF-α分泌,以及脾中淋巴细胞增殖,而S-COS和硫酸岩藻糖则不能。结论 B-COS对小鼠免疫功能的调节作用优于S-COS

辐射诱导的DNA修复与细胞凋亡的ATP调控

综述了DNA辐射损伤导致的细胞阻遏于G1期以及在该时期对DNA的修复活动,提出了较大剂量辐射诱导的三磷酸腺苷不足导致细胞凋亡的假说,并分析了细胞走向凋亡与修复的辨正关系

The Hydrogen Evolution Reaction on the Hydrogen Storage Alloy Electrode

贮氢合金电极上氢气的析出反应分为水分子的放电和吸附氢原子复合脱附两个步骤，即反应按ＶｏｌｍｅｒＴａｆｅｌ机理进行．反应的超电势η可以区分为η１和η２两个组成部分（η＝η１＋η２），反映了Ｖｏｌｍｅｒ和Ｔａｆｅｌ反应的极化特征．析氢反应的速度由二者混合控制，在高超电势区，主要则由Ｖｏｌｍｅｒ反应所控制．反应的法拉第阻抗也同样取决于界面放电Ｖｏｌｍｅｒ反应．交换电流密度为～１０－６Ａ·ｃｍ－２，说明贮氢电极在氢反应中的催化活性与金属镍电极相当．The hydrogen evolution reaction was studied in 1 mol/L KOH solution on the hydrogen storage alloy Mm(NiCoMnAl) 5 electrode using open circuit potential decay and ac impedance technique. The reaction was found to proceed by the Volmer(discharge)-Tafel(recombination)mechanism. The measured overpotential η can be subdivided into two components η 1 and η 2 corresponding to the elementary Volmer and Tafel reaction. The Faradaic impedance was analyzed and characterized by the Volmer reaction. Then the exchange current density was evaluated . It was founded that the activity of hydrogen storage alloy electrode for the hydrogen evolution reaction was similar to that of Ni electrode.作者联系地址：北京有色金属研究总院,北京科技大学应用科学院,武汉大学化学系Author's Address: Department of Physical Cheistry,University of Science and Thechology Beijing, Beijing 100083 Yang Hanxi Department of Chemistry,Wuhan University,Wuhan 43007