XMolecular Cloning and Sequence Analyses of cDNAs Encoding Seven C2type Lectin2like Protein Subunits from Daboia russellii siamensis

按照Promega 公司的mRNA 提取试剂盒操作手册, 从圆斑蝰蛇( Daboia russellii siamensis ) 的毒腺中提 取mRNA ; 利用RT2PCR 的方法进行体外扩增, 获得C - 型凝集素蛋白的基因, 克隆到pMD182T 载体中。随机挑 选14 个阳性克隆进行核酸测序, 获得7 个编码不同蛇毒C - 型凝集素样蛋白亚基的cDNA , 分别命名为DRS2L1 、 DRS2L2 、DRS2L3 、DRS2L4 、DRS2L5 、DRS2L6 和DRS2L7 。由基因序列推导出的氨基酸序列表明, 克隆到的7 个蛇 毒C - 型凝集素样蛋白的亚基中均有糖识别结构域存在。BLAST 分析显示, 仅有DRS2L1 的蛋白序列与目前已知 的蛇毒C - 型凝集素样蛋白的α亚基相似。序列同源性比较并结合半胱氨酸位点分析, 推测DRS2L1 和DRS2L2 可能分别是圆斑蝰蛇毒Ⅹ因子激活剂的轻链LC2 和LC1 。DRS2L3 和DRS2L4 可能是高分子量的蛇毒C - 型凝集 素样蛋白的β亚基, 而DRS2L5 和DRS2L6 可能是低分子量的蛇毒C - 型凝集素样蛋白的β亚基。DRS2L7 可能是 类似于血小板膜糖蛋白Ib 结合蛋白的β亚基。

盐胁迫下杜氏盐藻(Dunaliella salina)cDNA文库的构建与新表达序列标签(EST)的获取、分析

在成功养殖杜氏盐藻(Dunaliella salina)的基础上,采用Takara cDNA文库构建试剂盒,构建盐胁迫下(1.5 mol/L NaCl)杜氏盐藻的cDNA文库.经鉴定,原始文库的滴度达1.2×106cfu/mL,重组率高达95%,且多数插入片段均在500 bp以上.对表达序列标签(expressed sequence tag,EST)分析发现,杜氏盐藻基因组中包含大量未鉴定的新基因.随机挑取60个单克隆进行序列测定,将所测序列经Blast比对等生物信息学方法分析后,发现其中三分之一,即20

彩鲫Ran基因全长cDNA的克隆及其组织表达特异性分析

根据Ran的保守区序列设计简并引物 ,结合SMARTcDNA合成及RACE PCR技术 ,克隆到彩鲫(Carassiusauratuscolorvariety)的Ran基因的cDNA全长 ,其编码区全长为 6 4 8bp ,编码 2 15个氨基酸。采用BLAST程序在NCBI数据库中对其进行同源基因搜索 ,结果表明 ,其推测的编码氨基酸序列与斑马鱼和鲑鱼的Ran基因编码的氨基酸序列的同源性分别高达 98%和 97%。还对其编码区全长序列进行了原核表达 ,以经纯化的表达蛋白免疫家兔 ,制备出了具有较高特异性

Upstream regulatory region of zebrafish lunatic fringe: Isolation and promoter analysis

Lunatic fringe (Lfng), one modulator of Notch signaling, plays an essential part in demarcation of tissues boundaries during animal early development, especially somitogenesis. To characterize the promoter of zebrafish 1fng and generate somite-specific transgenic zebrafish, we isolated the upstream regulatory region of zebrafish 1fng by blast search at the Ensembl genome database (http://www. ensembl.org) and analyzed the promoter activity using green fluorescent protein (GFP) as a reporter. Promoter activity assay in zebrafish shows that the 0.2-kb fragment containing GC-box, CAAT-box, and TATA-box can direct tissue-specific GFP expression, while the 0.4-kb and 1.2-kb fragments with further upstream sequence included drive GFP expression more efficiently. We produced 1fngEGFP-transgenic founders showing somite-specific expression of GFP and consequently generated a hemizygous 1fngEGFP-transgenic line. The eggs from 1fngEGFP-transgenic female zebrafish show strong GFP expression, which is consistent to the reverse-transcription polymerase chain reaction PCR (RT-PCR) detection of 1fng transcripts in the fertilized eggs. This reveals that zebrafish 1fng is a maternal factor existing in matured eggs, suggesting that fish somitogcnesis may be influenced by maternal factors.

Identification of three duplicated Spin genes in medaka (Oryzias latipes)

Gene and genomic duplications are very important and frequent events in fish evolution, and the divergence of duplicated genes in sequences and functions is a focus of research on gene evolution. Here, we report the identification and characterization of three duplicated Spindlin (Spin) genes from medaka (Oryzias latipes): OlSpinA, OlSpinB, and OlSpinC. Molecular cloning, genomic DNA Blast analysis and phylogenetic relationship analysis demonstrated that the three duplicated OlSpin genes should belong to gene duplication. Furthermore, Western blot analysis revealed significant expression differences of the three OlSpins among different tissues and during embryogenesis in medaka, and suggested that sequence and functional divergence might have occurred in evolution among them. © 2005 Elsevier B.V. All rights reserved.

Molecular cloning and characterisation of a fish PKR-like gene from cultured CAB cells induced by UV-inactivated virus

The double-stranded-RNA-dependent protein kinase (PKR) is an important component in an antiviral defence pathway that is mediated by interferon (IFN) in vertebrates. Previously, some important IFN system genes had been identified from an IFN-producing CAB (crucian carp Carassius auratus blastulae embryonic) cells after treatment with UV-inactivated GCHV (grass carp haemorrhage virus). Here, a fish PKR-like gene, named CaPKR-like, is cloned and sequenced from the same virally infected CAB cells. It has 2192 base pairs in length with a largest open reading frame (ORF) encoding a protein of 513 amino acid residues. BLAST search reveals that the putative CaPKR-like protein is most homologous to human PKR and also has a high-level homology with all members of a family of eIF2alpha kinases. Structurally, CaPKR-like possesses a conserved C-terminal catalytic domain of eIF2alpha kinase family and the most similarity to mammalian PKRs. Within its N-terminus, there are no dsRNA-binding domains conserved in mammalian PKRs instead of two putative Z-DNA binding domains (Zalpha). Like mammalian PKRs, CaPKR-like had a very low level of constitutive expression in normal CAB cells but was up-regulated in response to active GCHV, UV-inactivated GCHV and CAB IFN, implying that the transcriptional activation of CaPKR-like by viral infection is mediated possibly by newly produced CAB IFN, which was further supported by using cycloheximide, a potent inhibitor of protein synthesis. The results together suggested that CaPKR-like was the first identified fish gene most similar to mammalian PKRs. (C) 2004 Elsevier Ltd. All rights reserved.

Growth of aligned single-walled carbon nanotubes under ac electric fields through floating catalyst chemical vapour deposition

Through floating catalyst chemical vapour deposition(CVD) method, well-aligned isolated single-walled carbon nanotubes (SWCNTs) and their bundles were deposited on the metal electrodes patterned on the SiO2/Si surface under ac electric fields at relatively low temperature(280 degrees C). It was indicated that SWCNTs were effectively aligned under ac electric fields after they had just grown in the furnace. The time for a SWCNT to be aligned in the electric field and the effect of gas flow were estimated. Polarized Raman scattering was performed to characterize the aligned structure of SWCNTs. This method would be very useful for the controlled fabrication and preparation of SWCNTs in practical applications.

Viruses' complete genomes classification based on geometrical learning

In this paper, we proposed a method of classification for viruses' complete genomes based on graph geometrical theory in order to viruses classification. Firstly, a model of triangular geometrical graph was put forward, and then constructed feature-space-samples-graphs for classes of viruses' complete genomes in feature space after feature extraction and normalization. Finally, we studied an algorithm for classification of viruses' complete genomes based on feature-space-samples-graphs. Compared with the BLAST algorithm, experiments prove its efficiency.

Effects and numerical analysis of argon gas flow on the oxygen concentration in Czochralski silicon single crystal growth

Argon gas, as a protective environment and carrier of latent heat, has an important effect on the temperature distribution in crystals and melts. Numeric simulation is a potent tool for solving engineering problems. In this paper, the relationship between argon gas flow and oxygen concentration in silicon crystals was studied systematically. A flowing stream of argon gas is described by numeric simulation for the first time. Therefore, the results of experiments can be explained, and the optimum argon flow with the lowest oxygen concentration can be achieved. (C) 2002 Elsevier Science B.V. All rights reserved.

Determination of the interdiffusion coefficients of liquid Zn and Sn using Ta/Zn-Sn/Si trilayers

In this paper we present a new method for measuring diffusion coefficients in liquid metals under convection-less conditions with solid/liquid-liquid/solid trilayer. The advantage of this kind of trilayer is that effects from gravity-induced convection and Marangoni-convection can be omitted, so that the diffusion coefficient is determined more accurately. The Ta/Zn-Sn/Si trilayer were prepared with a multi-target ion-beam sputtering deposition technique and annealed in an electric furnace under an argon atmosphere. The interdiffusion of liquid zinc and tin at 500 degrees degree C was investigated. The diffusion concentration profiles were determined by energy dispersive spectroscopy. The interdiffusion coefficients range from 1.0x10(-6)cm(2)/s to 2.8x10(-6)cm(2)/s, which is less than previous values measured by capillary reservoir technique under 1g-environment where various convection exist. The precise interdiffusion coefficients of liquid zinc and tin result from the removing of disturbances of various kinds of convection.

Semi-insulating GaAs grown in outer space

A semi-insulating GaAs single crystal ingot was grown in a recoverable satellite, within a specially designed pyrolytic boron nitride crucible, in a power-traveling furnace under microgravity. The characteristics of a compound semiconductor single crystal depends fundamentally on its stoichiometry, i.e. the ration of two types of atoms in the crystal. a practical technique for nondestructive and quantitative measuring stoichiometry in GaAs single crystal was used to analyze the space-grown GaAs single crystal. The distribution of stoichiometry in a GaAs wafer was measured for the first time. The electrical, optical and structural properties of the space-grown GaAs crystal were studied systematically, Device fabricating experiments prove that the quality of field effect transistors fabricated from direct ion-implantation in semi-insulating GaAs wafers has a close correlation with the crystal's stoichiometry. (C) 2000 Elsevier Science S.A. All rights reserved.

生物油热解与燃烧特性的实验研究

生物质快速热解制油技术能以连续的工艺和工厂化的生产方式将木屑等生物质转化为易储存、易运输、能量密度高的生物油，是目前受到较多关注的一种转换技术。生物油既可以在锅炉中直接燃烧使用，也可用于热解气化制备合成气，再进一步合成为高品质的液体燃料。 为更好地处理生物油燃烧与热解过程中出现的问题，并为燃烧与热解反应装置的设计及优化提供必要数据，本文首先对由木屑在自热式生物质热解液化装置中热解得到的生物油进行了各种理化特性的分析，之后利用热重、热重-红外联用、管式炉等对生物油的热解与燃烧特性进行了实验研究。 生物油在氮气与氧气气氛下、不同升温速率的热重分析试验表明：生物油的热解分为两个阶段，第一阶段为生物油中低沸点有机物的挥发以及各组分间反应生成各类产物的过程，第二阶段为各种重组分的裂解过程。而生物油的燃烧则分为三个阶段，即前期的挥发与裂解和最后焦炭的燃烧过程。升温速率的升高使得氮气气氛中生物油样品的初始失重温度、失重峰值温度及对应的最大失重速率均有所增大，且在较高升温速率(20℃/min)下，较少含炭残余物形成。随升温速率升高，生物油着火温度提高，最终失重率无显著变化。采用热重-红外联用技术，对生物油热解过程中所释放气体进行了实时监测，在线分析结果表明，反应初始阶段主要析出物为自由水、低沸点的酸类、醇类、醛类、酮类等，随后主要释放物为水、CO2等，主要来自重组分的裂解。最后根据热重数据对热解与燃烧各段反应进行了动力学拟合。动力学分析结果表明：氮气气氛中生物油的热解过程可用两个一级反应来描述，对应其热解过程中的两个不同阶段，而生物油的燃烧过程可用三个一级反应来表示。 生物油的管式炉热解实验表明：随热解温度的升高，生物油产气率不断提高，在1100℃时达到最大值398ml/g。生物油热解气体产物中主要包含H2、CO、CO2及烃类如CH4、C2H4、C2H6等,产气热值在16.9～19.1MJ/Nm3间。在900℃下，生物油各种产物气体、残炭、焦油的比例约为30:6:64,残炭含量低于同温度下木粉热解结果，而焦油含量较高。

印刷线路板废弃物的热解与动力学实验研究

分别应用管式炉反应器和热重分析手段对印刷线路板废弃物的热解行为和热解动力学进行了实验研究。在管式炉中，研究不同的热解温度：700～950℃，对产物分布和气体成分分布的影响。实验结果表明：PCB热解气体的主要成分是H2和CO2，气体的热值较低，仅为2.09～5.41MJ/m^3，PCB不适合以气体产物为目标的能源利用方式。应用Friedman方法对PCB的热解动力学进行了研究，求得PCB的热解动力学参数分别是：表观活化能190.92kJ/mol，反应级数5.97，指前因子lnA47.14min^-1。

Synthesis and random laser application of ZnO nano-walls: a review

This review paper summarises briefly some important achievements of our recent research on the synthesis and novel applications of nanostructure ZnO such as honeycomb shaped 3-D (dimension) nano random-walls. A chemical reaction/vapour transportation deposition technique was employed to fabricate this structure on ZnO/SiO2/Si substrate without any catalyst and additive in a simple tube furnace to aim the low-cost and high qualified samples. Random laser action with strong coherent feedback at the wavelength between 375 nm and 395 nm has been firstly observed under 355 nm optical excitation with threshold pumping intensity of 0.38 MW/cm(2).

Study on the technology of thermal cracking of paraffin to alpha olefins

Alpha olefins are mainly produced from paraffin cracking in China, but their quality is not good because of bad quality of cracking feed and outdated technology. The technology of paraffin once-through cracking, paraffin recycle cracking of removing the heavy fraction after wax vaporizing and that of removing the heavy fraction before wax vaporizing were investigated in this paper. It was found that the technology of paraffin recycle cracking of removing the heavy fraction before wax vaporizing is new and better under the same operating conditions. Using hard paraffin (mp 54-56 degrees C) as feed, the high-quality alpha olefins products (C-5-C-21) containing more than 97 wt% of olefins and more than 88 wt% of alpha olefins are produced under optimum process conditions, which are a steam to paraffin ratio of 15 wt%, process temperature of 600 degrees C, low hydrocarbon partial pressure and residence time of 2 s. In addition, with the technology of the second injecting steam in ethylene cracking used in paraffin cracking, producing coke in paraffin cracking furnace has been markedly reduced.