芦荟叶的特异结构、叶内生物活性成分及其与逆境适应的关系

叶是芦荟显著且最有利用价值的器官。世界上对芦荟的利用已达很高水平,对芦荟属植物叶中化学成分的种类、含量及分布特性已有较清楚认识。同时,业已发现,芦荟叶片的结构、叶内生物活性成分与其逆境适应之间关系密切。适度胁迫促进芦荟叶中生物活性成分的积累,改善N素及P、Si等矿质营养状况显著促进其叶中生物活性物质的生产、增强植株对逆境的适应性。对芦荟生理生态学的深入研究,可为芦荟抗逆栽培、新品种培育、合理利用及开发新优芦荟食品提供有力支撑。文章对芦荟叶结构的特异性、叶中的生物活性成分、叶中重要生物活性成分与叶结构的关系,以及芦荟叶片结构、叶中生物活性成分与其植株对逆境适应的研究进展进行了述评。

橡胶树雌蕊特异结构的发现初报

橡胶树(Hevea brasiliensis Muell.Arg.)的蒴果中通常含有3颗种子,但大田调查中发现,有含4颗种子和2颗种子的现象。对3个品系的橡胶树蒴果进行大田调查,并对雌蕊进行石蜡切片观察,结果表明:橡胶树的雌蕊中均存在四心室的现象,其发生频率品系间差异较大,没有观察到二心室的雌蕊;在橡胶树雌蕊中存在单个心室内2个胚珠的现象,品系间发生比率差异较大;3个品系的橡胶树均存在4颗种子的蒴果,品系间发生比率差异较大;只有GT1中存在2颗种子的蒴果。橡胶树4颗种子的蒴果由四心室雌蕊发育而来,2颗种子蒴果的形成原因有待进一步研究。

实时荧光定量PCR检测转基因玉米MON863结构特异基因的测量不确定度

[目的]对实时荧光定量PCR检测转基因玉米MON863结构特异基因的测量不确定度进行评定。[方法]使用转基因玉米MON863结构特异实时定量PCR方法测定含量为1%的转基因玉米MON863样品(CRM)中结构特异片段的含量,并从扩增反应、数据处理以及微量移液器等不确定度来源,评定测量的不确定度。[结果]研究得到uA=1.7×10-2,uB=9.0×10-4,uC=1.7×10-2,U95=0.036,测量结果为1.08%±0.036。[结论]转基因玉米MON863结构特异实时定量PCR方法检测结果的主要不确定度来自检验过程中的随机效应。

实时荧光定量PCR检测转基因玉米NK603结构特异基因的测量不确定度研究

应用四川省农业科学院分析测试中心实验室建立的转基因玉米NK603结构特异实时定量PCR方法测定含量为2%的转基因玉米NK603样品中结构特异片段的含量,并从扩增反应、数据处理以及微量移液器等不确定度来源,评定了测量的不确定度。结果表明,uA=0.0003,uB=0.001,uC=0.001,U95=0.002,测量结果为1.6%±0.002%。NK603结构特异实时定量PCR方法检测结果的主要不确定度来自检验过程中的随机效应。

大鼠胃经沿线特异组织结构与“循经取穴”关系的研究

目的:根据大鼠胃经沿线特异组织结构和针刺镇痛经络效应的相关性探讨其与“循经取穴”针刺作用的关系。方法:在大鼠胃经沿线特异组织结构上选择包括“后三里”在内的3个针刺位点,分别进行针刺前后痛阈测定,并与特异组织结构旁2个对照位点针刺前后的痛阈进行比较,同时对不同针刺位点特异组织结构上镇痛效应物质含量进行放免检测对比。结果:在胃经沿线特异组织结构上3个位点针刺前后痛阈变化明显,在特异组织结构旁2个对照位点上针刺前后痛阈未见有意义改变。针刺“后三里”与针刺特异组织结构旁2个对照位点的胃经沿线特异组织结构上β-内啡肽(β-EP)、强啡肽(DynA)含量差异显著。结论:正常大鼠胃经沿线特异组织结构具有激发针刺效应的特异性。

基于脑部特异子结构分析的阿尔兹海默症分类

近年来基于核磁共振影像学(Magnetic Resonance Imaging,MRI)的阿尔兹海默症(Alzheimer′s disease,AD)分类备受关注。研究表明,阿尔兹海默症与脑部子结构的形态学密切相关,现有研究通常是直接选取海马体、杏仁体等医学分析上具有特异性的子结构进行探究,并没有全面地去进行特异性子结构筛选。为了探究AD与子结构特异性之间的相关性,主要做了以下2个方面的工作:(1)提取脑部子结构的体积信息作为特征向量进行分类,并且通过机器学习决策树输出对分类起决定性作用的子结构。(2)以ResNet-3D为基础构建了网络,引入注意力子模块,过滤MRI图像中的冗余信息,同时将机器学习提取的特异性子结构的体积信息与高维特征信息进行融合,再进行分类。选用ADNI公开数据集上765名患者(正常(Cognitively Normal,CN)358名、AD患者407名)不同时期的2294个脑部MRI图像进行了实验验证。实验结果表明,决策树中对分类起主要作用的子结构为海马体、杏仁体和鼻内嗅皮层这三个区域,提出的方法,优于其他5种当前方法,可以作为一种很有前景的AD辅助诊断方法。

苏云金芽孢杆菌杀虫晶体蛋白基因的结构

本文从基本结构和特异结构两方面对苏云金芽孢杆菌杀虫晶体蛋白基因结构的最新研究成果进行了综述

Microstructural characteristics of joint region during diffusion-brazing of magnesium alloy and stainless steel using pure copper interlayer

A novel joining method,double-stage diffusion-brazing of an AZ31 magnesium alloy and a 304L austenitic stainless steel,was carried out using a pure copper interlayer.The solid-state diffusion bonding of 304L to copper was conducted at 850 ℃ for 20 min followed by brazing to AZ31 at 520 ℃ and 495 ℃ for various time.Microstructural characteristics of the diffusion-brazed joints were investigated in detail.A defect free interface of Fe-Cu diffusion area appeared between the Cu alloy and the 304L steel.Cu-Mg reaction products were formed between AZ31 and Cu alloys.A layered structure including AZ31/Cu-Mg compounds/Cu/Fe-Cu diffusion layer/304L was present in the joint.With time prolonging,the reduction in the width of Cu layer was balanced by the increase in the width of Cu-Mg compounds zone.Microhardness peaks in the zone between AZ31 and Cu layer were attributed to the formation of Mg-Cu compounds in this zone.

Uncertainty in Measuring Construct-specific Fragments of Genetically Modified Maize MON863 by Real Time Quantitative PCR

[Objective] The study aimed at evaluating the uncertainty in measuring the construct-specific fragments of genetically modified maize MON863 by real time quantitative PCR.[Method] The content of construct-specific fragments in MON863 samples was determined by real time quantitative PCR,and then the uncertainty of measurement result was evaluated according to the sources of uncertainty like the PCR system,the data processing and the micropipette.[Result] Type A evaluation of uncertainty（uA） in the measurement was 1.7×10^-2;Type B evaluation of uncertainty（uB） was 9.0×10^-4;the combined standard uncertainty（uC） was 1.7×10^-2;the expanded uncertainty（U95） was 0.036 and the finally measured result was 1.08%±0.036.[Conclusion] The main uncertainty of the result measured by real time quantitative PCR came from the randomizing effect in the experimental process.

经络黑箱方法研究及意义

经络的特异实质结构至今尚未探明 ,但已初步研究掌握了经络现象的规律性。古代和现代对于经络的研究常有黑箱方法的一些最基本特征。现代系统科学的黑箱方法 ,不是直接考察经络的内部结构 ,而是利用外部观察和试验来考察经络系统的输入输出及其动态过程 ,研究经络的功能和特性 ,探索其结构和机理的科学方法。现代经络黑箱方法的研究 ,也为经络诊断和治疗提高了精确性和有效性 。

克雅二氏病检测有了新试剂

单克隆抗体15B3已被研制出来用于传染性海棉状脑病（TSE3）的检测,15B3可检测出微孔蛋白的病原特异结构,从而可以对人和动物的机体进行检测,也可用来检测血液中的微孔蛋白。 微孔蛋白被看作是引起传染性海绵状脑病潜在的一种传染媒介,它含有细胞微孔蛋白的一种异常结构。 研究人员说,用单克隆抗体15B3可检测出染病的羊,牛,人等体内微孔蛋白质中的三种抗原表位,这些抗原表位不存在于细胞微孔蛋白中。 研究人员同时也探讨了6H4的特性。

液化气燃净器

液化气燃净器专利号：９４２２２１５９这是一种装在液化气钢瓶角阀下端的管件，可使残液在罐内气压下经管件雾化后送出罐外燃净。它由底部连通的长、短双管构成，下部有进液口及进液元件，上端接头与角阀孔构成滑套，其带单向阀的正压雾化结构为国内独创，性能优，它不需...

GPCR A2AAR Agonist Binding and Induced Conformation Changes of Functional Switches

Agonist binding of A2A adenosine receptor （A2AAR） shows protective effects against inflammatory and immune. Efforts are exerted in understanding the general mechanism and developing A2AAR selectively binding agonists. Using molecular dynamics （MD） simula- tions, we have studied the interactions between A2AAR and its agonist （adenosine）, and analyzed the induced dynamic behaviors of the receptor. Key residues interacting with adenosine are identified： A63^2.61,I66^2.64,V84^3.32,L85^3.33,T88^3.36,F168^5.29,M177^5.38,L249^6.51,H250^6.52 and N253^6.55 interacting with adenosine with affinities larger than 0.5 kcal/mol. Moreover, no interaction between adenosine and L167^5.28 is observed, which supports our previous findings that L1675^5.28 is an antagonist specific binding reside. The dynamic be- haviors of agonist bound A2AAR are found to be different from apo-A2AAR in three typical functional switches： （i） tight ＂ionic lock＂ forms in adenosine-A2AAR, but it is in equilibrium between formation and breakage in apo-A2AAR; （ii） the ＂rotamer toggle switch＂, T88^3.36/F242^6.44/W246^6.48, adopted different rotameric conformations in adenosin-A2AAR and apo-A2AAR; （iii） adenosine-A2AAR has a flexible intracellular loop 2 （IC2） and s-helical IC3, while apo-A2AAR preferred s-helical IC2 and flexible IC3. Our results indicate that agonist binding induced different conformational rearrangements of these characteristic functional switches in adenosine-A2AAR and apo-A2AAR.

Structural insights into a dual-specificity histone demethylase ceKDM7A from Caenorhabditis elegans

Histone lysine methylation can be removed by JmjC domain-containing proteins in a sequence- and methylationstate-specific manner. However, how substrate specificity is determined and how the enzymes are regulated were largely unknown. We recently found that ceKDM7A, a PHD- and JmjC domain-containing protein, is a histone demethylase specific for H3K9me2 and H3K27me2, and the PHD finger binding to H3K4me3 guides the demethylation activity in vivo. To provide structural insight into the molecular mechanisms for the enzymatic activity and the function of the PHD finger, we solved six crystal structures of the enzyme in apo form and in complex with single or two peptides containing various combinations of H3K4me3, H3K9me2, and H3K27me2 modifications. The structures indicate that H3Kgme2 and H3K27me2 interact with ceKDMTA in a similar fashion, and that the peptide-binding specificity is determined by a network of specific interactions. The geometrical measurement of the structures also revealed that H3K4me3 associated with the PHD finger and H3K9me2 bound to the JmjC domain are from two separate molecules, suggesting a trans-histone peptide-binding mechanism. Thus, our systemic structural studies reveal not only the substrate recognition by the catalytic domain but also more importantly, the molecular mechanism of dual specifieity of ceDKM7A for both H3K9me2 and H3K27me2.

Secondary Structure and Neurotrophic Effect of a 33.1 kDa Specific Protein (SSP-33.1) in Spinal Sensory Ganglia

Aim To analyze the secondary structure and neurotrophic effect of a specific protein in sensory neurons. Methods Comparison of the proteins expressed in the rat spinal sensory neurons and motor neurons was made by two dimensional electrophoresis. One specific protein in sensory neurons was isolated and purified by DEAE Sephacel ion exchange chromatography and high performance liquid chromatography. A primary analysis of its secondary structure by circular dichroism, and its neurotrophic effects were investigated using the model of dorsal root ganglia(DRG) cultured in vitro . Results The molecular weight and isoelectric point of the protein were 33 1 kDa and 5 52, respectively. Its circular dichroism showed that there were 20 8% α helix, 54 8% β sheet, 7 3% turn, and 17 1% random coil in its secondary structure. Biological experiments showed that the protein could promote the neurite outgrowth of DRG. Conclusion A specific protein in spinal sensory tissue with molecular weight of 33 1 kDa has been purified. There is mainly β sheet in the secondary structure of the protein. And the protein has neurotrophic effects in the model of DRG.

Expression and Identification of Inclusion Forming-related Domain of NS80 Nonstructural Protein of Grass Carp Reovirus

Grass carp reovirus （GCRV）, a double stranded RNA virus that infects aquatic animals, often with disastrous effects, belongs to the genus Aquareovirus and family Reoviridea. Similar to other reoviruses, genome replication of GCRV in infected cells occurs in cytoplasmic inclusion bodies, also called viral factories. Sequences analysis revealed the nonstmctural protein NS80, encoded by GCRV segment 4, has a high similarity with μNS in MRV（Mammalian orthoreovimses）, which may be associated with viral factory formation. To understand the function of the μNS80 protein in virus replication, the initial expression and identification of the immunogenicity of the GCRV NS80 protein inclusion forming-related region （335-742） was investigated in this study. It is shown that the over-expressed fusion protein was produced by inducing with IPTG at 28℃. In addition, serum specific rabbit antibody was obtained by using super purified recombinant NS80（335-742） protein as antigen. Moreover, the expressed protein was able to bind to anti-his-tag monoclonal antibody （mouse） and NS80〈335.742） specific rabbit antibody. Further western blot analysis indicates that the antiserum could detect NS80 or NS80C protein expression in GCRV infected cells. This data provides a foundation for further investigation of the role of NS80 in viral inclusion formation and virion assembly.

Isozyme Analysis of Spotted Halibut Verasper variegatus Temminck et Schlegel

To investigate the tissue-specificities of isozymes and the genetic structureof wild spotted halibut ( Verasper variegatus) population, horizontal starch gel electrophoresiswas performed on 45 individuals collected in part of the Yellow Sea. The performances of 17 isozymesin 8 kinds of tissues or organs were screened preliminarily in a TC-7.0 buffer system. The resultsshowed that the screened isozymes displayed remarkable tissue-specificities. Finally, 14 enzymes(AAT, ADH, EST, OPI, G3PDH, IDHP, LAP, LDH, MDH, MPI, PGDH, PGM, SDH and SOD) and 4 kinds of tissues(eye, skeleton muscle, liver and heart) were selected for genetic analysis. Fourteen isozymes areencoded by 20 loci, and 9 of them are polymorphic. The polymorphic loci are AAT-1~*, GPI-2~*,G3PDH~*, IDHP-1~*, LDH~*, MPI~*, PGM-1~*. PGM-2~* and SDH~*, and the proportion of polymorphic lociis 0.4500 (P_(0.99)) ? The mean values of observed and expected heterozygosities are 0.0278and 0.0265, respectively and the average effective number of alleles is 1.0675.

AtGGM2014, an Arabidopsis gene co-expression network for functional studies

Gene co-expression networks provide an important tool for systems biology studies. Using microarray data from the Array Express database, we constructed an Arabidopsis gene co-expression network, termed At GGM2014, based on the graphical Gaussian model, which contains 102,644 co-expression gene pairs among 18,068 genes. The network was grouped into 622 gene co-expression modules. These modules function in diverse house-keeping, cell cycle, development, hormone response, metabolism, and stress response pathways. We developed a tool to facilitate easy visualization of the expression patterns of these modules either in a tissue context or their regulation under different treatment conditions. The results indicate that at least six modules with tissue-specific expression pattern failed to record modular regulation under various stress conditions. This discrepancy could be best explained by the fact that experiments to study plant stress responses focused mainly on leaves and less on roots, and thus failed to recover specific regulation pattern in other tissues. Overall, the modular structures revealed by our network provide extensive information to generate testable hypotheses about diverse plant signaling pathways. At GGM2014 offers a constructive tool for plant systems biology studies.

The structure of Rap1 in complex with RIAM reveals specificity determinants and recruitment mechanism

The small GTPase Rap1 induces integrin activation via an inside-out signaling pathway mediated by the Rapl-interacting adaptor mol- ecule （RIAM）. Blocking this pathway may suppress tumor metastasis and other diseases that are related to hyperactive integrins. However, the molecular basis for the specific recognition of RIAM by Rap1 remains largely unknown. Herein we present the crystal structure of an active, GTP-bound GTPase domain of Rap1 in complex with the Ras association （RA）-pleckstrin homology （PH） structural module of RIAM at 1.65 A. The structure reveals that the recognition of RIAM by Rap1 is governed by side-chain interactions. Several side chains are critical in determining specificity of this recognition, particularly the Lys31 residue in Rap1 that is oppositely charged compared with the Glu31/Asp31 residue in other Ras GTPases. Lys31 forms a salt bridge with RIAM residue Glu212, making it the key specificity determinant of the interaction. We also show that disruption of these interactions results in reduction of Rapl：RIAM association, leadingto a loss of co-clustering and cell adhesion. Our findings elucidate the molecular mechanism by which RIAM med- iates Rapl-induced integrin activation. The crystal structure also offers new insight into the structural basis for the specific recruitment of RA-PH module-containing effector proteins by their smaU GTPase partners.