检索结果-南通市图书馆

Modeling the intracellular dynamics for Vif-APO mediated HIV-1 virus infection

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2010年第22期55卷 2329-2340页

作者： WANG Yi1,2 & LAI LuHua1,3 1 Center for Theoretical biology, Peking University, Beijing 100871, China 2 School of Physics, Peking University, Beijing 100871, China 3 BNLMS, State key laboratory for Structural Chemistry of Unstable and Stable Species, College of Chemistry and molecular Engineering, Peking University, Beijing 100871, China Center for Theoretical biology Peking University Beijing 100871 China School of Physics Peking University Beijing 100871 China BNLMS State Key Laboratory for Structural Chemistry of Unstable and Stable Species College of Chemistry and Molecular Engineering Peking University Beijing 100871 China

The viral infectivity factor (Vif) was found to be essential for controlling HIV-1 virus infectivity. It targets cellular antiviral proteins in APOBEC family (APO) to trigger its fast degradation and inhibits APO packaging into nascent virion. In the present study, we propose a mathematical model to quantitatively study the intracellular dynamics of these typical virus-host interactions. Four sets of published experimental data were compared with simulation results to justify the model. Systematic parameter sensitivity and perturbation analysis showed that parameters related to APO are crucial to the infectivity of newly synthesized HIV-1 virus. Interestingly, we discovered that the synthesis rate of the viral structure protein Gag and the required number per nascent virion are optimized to achieve high virion production with minimal level of packaged APO, and large portion of model parameters are beneficial to virus only within a relatively small range. Furthermore, minor variations in several parameters related to viral protein Tat, the activator of viral RNA synthesis, were found to induce switch-like behaviors on both incorporated Vif and APO. These findings may provide new insights for understanding the high mutation rate of HIV-1 virus and its latency, as well as help identify key targets for therapeutic design.

关键词：病毒感染载脂蛋白 HIV 细胞内动力学抗病毒蛋白建模介导

Eavesdropping in a quantum secret sharing protocol based on Grover algorithm and its solution

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2010年第3期53卷 491-495页

作者： HAO Liang1, LI JunLin1 & LONG GuiLu1,2 1key laboratory for Atomic and molecular NanoSciences and Department of Physics, Tsinghua University, Beijing 100084, China 2Tsinghua National laboratory for Information Science and Technology, Beijing 100084, China 1. key laboratory for Atomic and molecular NanoSciences and Department of Physics Tsinghua University Beijing 100084 China2. Tsinghua National Laboratory for Information Science and Technology Beijing 100084 China

A detailed analysis has showed that the quantum secret sharing protocol based on the Grover algorithm (Phys Rev A, 2003, 68: 022306) is insecure. A dishonest receiver may obtain the full information without being detected. A quantum secret-sharing protocol is presents here, which mends the security loophole of the original secret-sharing protocol, and doubles the information capacity.

关键词： quantum secret sharing Grover algorithm quantum cryptography quantum search algorithm

Characterization of interspecific hybrids and backcross progenies from a cross between Oryza minuta and Oryza sativa

在线全文

学校读者我要写书评

暂无评论

Science China(Life Sciences) 2009年第12期52卷 1148-1155页

作者： GUO SiBin, QIN FaLan, ZHANG DuanPin & LIN XingHua· National key laboratory of Crop Genetic Improvement, National Center of Crop molecular Breeding, Huazhong Agricultural University, Wuhan 430070, China National key laboratory of Crop Genetic Improvement National Center of Crop Molecular Breeding Huazhong Agricultural University Wuhan 430070 China

Oryza minuta, a tetraploid wild relative of cultivated rice, is an important source for the genetic improvement. Interspecific hybrids were obtained from the cross of O. sativa L. (IR24) and O. minuta (Acc. No. 101133) with 5.58% crossability, which ranged from 0.11% to 1.62% in the backcross generations. The chromosome numbers of the backcross progenies were 24 to 48. Seven yield-related traits of the parents, hybrid F1, and backcross progenies were evaluated. Simple sequence repeat markers analysis showed that the polymorphism ratio of SSR bands between IR24 and Acc. No. 101133 was 93.2%. The average donor segment number, length, donor genome size, and percentage of donor genome of 92 BC3F1 plants (2n=24) were 24.1, 17.8 cM, 438.4 cM and 26.2%, respectively. They were complex variation and uneven among the chromosomes. These introgression lines could be used to identify the favorable genes of O. minuta and provide a new platform for the genetic improvement of cultivated rice.

关键词： Oryza sativa L. Oryza minuta interspecific hybridization backcross progeny introgression line

Luminescence resonance energy transfer based on β-NaYF_4:Yb,Er nanoparticles and TRITC dye

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2009年第10期52卷 1590-1595页

作者： SUN LingDong, GU JianQin, ZHANG ShuZhuo, ZHANG YaWen & YAN ChunHua Beijing National laboratory for molecular Sciences, State key Lab of Rare Earth Materials Chemistry and Applications & PKU-HKU Joint Lab in Rare Earth Materials and Bioinorganic Chemistry, College of Chemistry and molecular Engineering, Peking University, Beijing 100871, China 1. Beijing National laboratory for molecular Sciences State Key Lab of Rare Earth Materials Chemistry and Applications & PKU-HKU Joint Lab in Rare Earth Materials and Bioinorganic Chemistry College of Chemistry and Molecular Engineering Peking University Beijing 100871 China

β-NaYF4:Yb,Er nanoparticles (NPs) are one of the most efficient upconversion materials, which can convert near-infrared light to higher-energy light through multiple photon absorptions or energy transfer. In addition, they may be attractive alternative donors for luminescence resonance energy transfer (LRET) studies, because of their sharp absorption and emission profiles, high quantum yields, large anti-stokes shifts, long lifetime, low toxicity, and superior photo-stability. In principle, many problems of fluorescence resonance energy transfer (FRET), such as excitation of acceptors, emission overlaps between donors and acceptors, high background noise, potential toxicity, and instability, can be overcome using β-NaYF4:Yb,Er NPs as energy donors. Because the organic coating induced separation can significantly reduce the energy transfer efficiency and aqueous FRET system is difficult to be applied in devices, we demonstrate a novel NP-dye LRET system in solid state. The emission of the β-NaYF4:Yb,Er NPs at 539 nm overlaps with the absorption of the tetrametrylrhodarnine isothiocyante (TRITC), satisfying the requirement of LRET process. Since TRITC molecules are adsorbed on the β-NaYF4:Yb,Er NPs by an electrostatic interaction, the interaction distance is suitable for LRET without any further modulation. The resultant solid LRET system is ready for the further applications for devices.

关键词： upconversion emission β-NaYF4:Yb Er nanoparticles TRITC assembly luminescence resonance energy transfer (LRET)

Are small RNAs a big help to plants?

在线全文

学校读者我要写书评

暂无评论

Science China(Life Sciences) 2009年第3期52卷 212-223页

作者： MAO YingBo,XUE XueYi & CHEN XiaoYa National key laboratory of Plant molecular Genetics,Institute of Plant Physiology and Ecology,Shanghai Institutes for Biological Sciences,Chinese Academy of Sciences,Shanghai 200032,China 1. National key laboratory of Plant molecular Genetics Institute of Plant Physiology and Ecology Shanghai Institutes for Biological Sciences Chinese Academy of Sciences Shanghai 200032 China

The discovery of RNA interference(RNAi) has augmented our knowledge of gene regulation and presents a fascinating technology that has a great potential for application in genetic analysis,disease therapy,plant protection,and many other *** this review,we will focus on the biological functions of RNAi and its application in agriculture with a brief introduction to the history of its discovery and molecular mechanism.

关键词： RNA interference gene regulation plant protection

Development of Novel Binder for Hardmetal Powder Extrusion Molding

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2002年第6期18卷 569-571页

作者： Jicheng ZHOU and Baiyun HUANGState key laboratory for Powder Metallurgy, Central South University , Changsha 410083, China Lab. for Power Metall. Central South Univ. Changsha 410083 China

A novel binder system for hardmetal powder extrusion moulding (PEM) process has been developed. The binder system comprises a major fraction of a mixture of low molecular weight components (LMWCs) and a minor fraction of very finely dispersed polymer. The feedstocks are mixed as a thick slurry at a suitable temperature and are rapidly homogenized by stirring at an adequate shear force. The binders are removed by thermal debinding. The thermal debinding mechanism has been investigated by thermogravimetry (TG) and differential thermogravimetry (DTG). At the first stage of debinding, the LMWCs are removed. These open up pore channels which allows much faster removal of the remaining polymer component during the subsequent stage. The microstructures of the moulded green parts were observed by scanning electron microscopy (SEM). The debound samples were sintered at different temperatures, and the sintered samples properties were measured.

关键词： Binder Thermal debinding Hardmetal powder extrusion moulding

Analysis micro-mechanism of burrs formation in the case of nanometric cutting process using numerical simulation method

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2007年第2期50卷 129-137页

作者： HAN XueSong & HU YuanZhong State key laboratory of Tribology, Tsinghua University, Beijing 100084, China 1. State key laboratory of Tribology Tsinghua University Beijing 100084 China

Burrs (exit failure), being one of the important factors influencing the final precision of workpiece, have been widely studied. Today, with the development of manufacturing technology, the depth of cut falls into the range of nanometer or subnanometer, there may be some different disciplines dominating the burrs generation process. molecular dynamics (MD) emthod, which is different from continuous mechanics, plays an important role in describing microscopic world. Take the example of single crystal copper, this paper carries out MD analysis micro-mechanism of burrs generation process. The results show that the burrs geometry depends on the type of workpiece (ductile or brittle). The depth of cut is decreased in the case of positive burrs generation process while the depth of cut is increased in case of negative burrs generation process. keywords burr - molecular dynamics - micro-mechanism Supported by China Postdoctor Science Foundation (Grant No. 20060390458)

关键词： burr molecular dynamics micro-mechanism

SYNTHESIS OF A NEW JON PAIR COMPLEX CONTAINING MOLYBDENUM(V)AND SAMARIUM(Ⅲ)

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 1994年第7期5卷 617-618页

作者： Chun Ting SUN Ya Bin ZHU Qing Hong FU Xun LIU Shu Zhen YI(key laboratory of molecular Spectrum and molecular Structure Jilin University, Changchun, 130023)

A new ion-pair complex [Mo(dtc)4][Sm(dtc)4]was synthesized *** molecular structure and crystal structure was determined through X-rayDiffraction method.

关键词：

在线全文

学校读者我要写书评

暂无评论

酵母蛋白质YJL084c的磷酸化分析

生物化学与生物物理学报 2002年第4期34卷 433-438页

作者：石晓钟敖世洲中国科学院上海生命科学研究院生物化学与细胞生物学研究所分子生物学国家重点实验室中国科学院上海生命科学研究院生物化学与细胞生物学研究所分子生物学国家重点实验室上海200031

PCL6、PCL7(PAP1)和PHO80为酵母蛋白激酶PHO85的细胞周期蛋白因子 ,同属于PHO80亚类 ,它们在蛋白质序列上有较高的同源性 ,彼此在功能上有一定程度的重叠。YLR190w为先前鉴定的PCL7 PHO85的一个底物 ,根据BLAST比较 ,YJL0 84c与YJLR190... 详细信息

PCL6、PCL7(PAP1)和PHO80为酵母蛋白激酶PHO85的细胞周期蛋白因子 ,同属于PHO80亚类 ,它们在蛋白质序列上有较高的同源性 ,彼此在功能上有一定程度的重叠。YLR190w为先前鉴定的PCL7 PHO85的一个底物 ,根据BLAST比较 ,YJL0 84c与YJLR190w在一段区域内有一定的同源性 ,并且根据已公布公共数据库 ,YJL0 84c是PCL6的一个结合蛋白。利用双杂交系统分析了YJL0 84c与这三个细胞周期蛋白因子之间的相互作用 ,表明PCL7也可以结合YJL0 84c。利用免疫共沉淀证实它们在体内的相互作用 ;通过体外GST沉降分析 ,验证它们的体外相互作用。YJL0 84c的体外翻译产物可以被PCL7 PHO85复合物磷酸化 ,进一步分别表达纯化YJL0 84c的氨基末端、中间和羧端三部分的GST融合蛋白片段 ,PCL7 PHO85复合物可以磷酸化其中间部分 ,而对N末端和C末端则未表现出磷酸化。以该中间片段蛋白质为底物 ,进一步研究高低磷条件对其磷酸化的影响。PCL7 PHO85对YJL0 84c的磷酸化受到无机磷条件的明显影响 :高磷条件下 ,磷酸化程度高 ;而低磷条件下磷酸化程度低。有意思的是 ,PCL6 PHO85免疫沉淀复合物也表现出同样的磷酸激酶特征。于是分析PHO81与这三个细胞周期因子之间相互作用。此外 ,还构建了Yjl0 84c的缺失株 ,分析了缺失的可能影响。

关键词： PCL6 PCL7 YJL084c 磷酸化酵母双杂交系统