Microtubule associated protein tau binds to double-stranded but not single-stranded DNA

Tau, a major microtubule-associated protein of the neuron, which is known to promote the assembly of and to stabilize microtubules, has also been seen associated with chromatin in neuronal cell lines, but its role in this subcellular compartment is still unknown. In this study, the binding of tau to DNA was investigated using the electrophoretic mobility shift assay. Using polynucleotide as probe, we found that tau bound to double-stranded but not to single-stranded DNA. Formation of tau-polynucleotide complex was disrupted by alkaline pH and a high concentration of NaCl, but was not affected by dithiothreitol. Electron microscopy revealed that the protein associated with the nucleic acid in a necklacelike manner. DNA-cellulose chromatography and radioimmunodot-blot analyses showed that calf thymus histones VI-S, VII-S and VIII-S could replace both recombinant human brain tau₃₅₂ (tau-23) and tau₄₄₁ (tau-40) from DNA. Thus, tau appears to bind to DNA reversibly in the presence of histones. Received 24 November 2002; received after revision 28 December 2002; accepted 30 December 2002 RID="*" ID="*"Corresponding author.     

Photoelectrochemical synergetic degradation of Acid Orange II with TiO2 modified β-PbO2 electrode

Electrochemically assisted photocatalysis is an effective approach to improve photocatalytic efficiency. In this paper, modified β-PbO2 electrode was prepared by TiO2 co-deposition and characterized by SEM and XRD. Then 2.0g TiO2 modified β-PbO2 electrode (2.0 g TiO2 involved in the 200 mL co-deposition solution) was used in electrochemically assisted photocatalytic degradation of Acid Orange II and the influence of initial pH values was investigated when the potential applied across the electrodes was 1.5 V. When the potential applied was 2.5 V, the difference of the degradation process and the final products were studied. The results indicated that 2.0 g TiO2 modified β-PbO2 electrode was different from the unmodified one in that the β-PbO2 crystals became finer and the electrode became more compact and more uniform. The synergetic effect in electrochemically assisted photocatalytic degradation of Acid Orange Ⅱ was observed and degradation efficiency and TOC removal were the highest at initial solution pH 2.0. By UV-visible spectral analysis, it was proved that photoelectrochemical synergetic degradation of Acid Orange Ⅱ went through the step of producing main product maleic acid for the solution at the initial pH 2.0 within 2 h, but the degradation was slow for the solution at the initial pH 12.0.     

纳米固体超强酸SO4^2-/TiO2的制备及其催化活性

以廉价的无机盐TiCl4为原料,采用溶胶-凝胶法结合超临界流体干燥技术制备出纳米TiO2粉末,经硫酸溶液浸泡、活化后制成纳米固体超强酸SO4^2-/TiO2.着重探讨了纳米固体超强酸的制备条件,并将其用于乙酸正丁酯的合成反应以考察其催化活性.结果表明：该法制备的纳米固体超强酸SO4^2-/TiO2具有很强的催化活性,且制备成本低,反应时间短,酯化率高.     

活体细胞三维荧光图像恢复中的荧光衰减补偿

针对三维荧光显微镜成像中的光致漂白效应导致的图像质量下降问题，提出了一种荧光衰减曲线测量方法，并基于测量的荧光衰减曲线给出双指数曲线拟合，将拟合曲线用于活体细胞的三维荧光图像恢复．在此基础上给出期望最大化算法国像恢复结果，并对恢复结果做出分析．结果显示本文的方法可以对三维荧光显微成像中存在的荧光衰减进行有效补偿．     

Over-expression of an Arabi-dopsisd δ-OAT gene enhances salt and drought tolerance in transgenic rice

Riceisoneofthemostimportantcropsintheworld,sincemorethanhalfoftheworldspopulationisfedonrice(OryzasativaL.).Althoughmuchhasbeendoneonfoodsecurityforlong,osmoticstress,duetodroughtandsalinity,isstillthemostseriousfactorthataffectstheyieldofrice[1].Ithaslongbeenfoundthatplantsaccumulateosmolytestomaintainosmoticbalanceandtoprotectsubcellularstructures[2].Theseosmolytesaremainlysmallmolecularweightorganiccompoundsandproteinprotec-tants.Prolineisregardedasthemostwidely-distributedosmolyteandwitht…     

塔克拉玛干沙漠简单横向沙丘形态学示量特征

通过对塔克拉玛干沙漠不同区域发育的简单横向沙丘的形态学示量特征分析，表明简单横向沙丘的形态特征与沙源的供应有十分密切的关系，沙源的不同丰度导致简单横向沙丘的形态学参数之间有明显的不同，简单横向沙丘在发育过程中并不存在稳定的平衡状态，可能随沙源供应的改变其形态有所改变，而次生的横向沙丘由于主体沙丘对其有足够的沙源供应，因而形态可以得到充分发展，沙丘形态参数的统计数据表明，在简单形新月形沙丘-简单形横向沙丘-沙丘复合体的发展模式中，随沙源供应的增加，沙丘发育时间系列的延长以及其他因素如：风环境、植被等因素的作用，沙丘形态参数之间很难有确切的关系表达式。     

气动控制在液压机上的应用

阐述了液压机气动控制的工作原理，介绍了气动逻辑元件在液压传动中的应用，分析了气动传动的优缺点，并针对气动传动缺点，提出了解决方案。     

小系统局域网建设的设想

随着信息技术的发展，如何应用信息技术提高企业的生产力、生产效率显得日趋重要．将计算机网络技术引入到工程的设计及企业管理中已成为发展的必然，这一技术的应用势必大大地提高企业的综合竞争能力。本文就计算机网络技术在辽宁勘测院的生产及管理工作中应用的可行性、必要性及应用前景做了简要的分析和探讨．     

基于生态足迹分析法的可持续发展评估--以常州市新北区为例

以生态足迹分析方法为工具，对江苏省常州市新北区的可持续发展状况进行评估，计算得到该地区2002年的生态赤字达-1．2256hm^2．在此基础上分析生态赤字产生的原因，并提出促进该地区未来可持续发展的对策与措施。     

南瓜属4个栽培种种子蛋白及电泳图谱的比较

对南瓜属4个栽培种中的11个品种进行种子蛋白质含量及碱溶蛋白SDS-PAGE分析.结果显示,蛋白质含量在4栽培种间呈现一定的差异,在种内品种间则比较接近;非还原与还原条件下,4栽培种间蛋白谱带均有差异,可将各栽培种区别开,其中以还原条件下区别更为明显.栽培品种日本南瓜同时显示出中国南瓜和印度南瓜的特征条带,推测可能是2个种的种间杂交种.