圆网蛛类系统发生与网型进化

本文从妖面蛛总科和园蛛总科系统发生关系、园蛛总科网型不同的蜘蛛间的系统发生关系及蛛网构建行为等几个方面着重介绍了圆网蛛类系统发生及网型进化的研究进展.圆网蛛类系统发生与其网型进化有效地结合、进行综合研究将有助于圆网蛛类的起源及网型多样性的研究.     

大腹园蛛鞭毛样丝蛋白cDNA克隆

应用RT-PCR技术,从大腹圆蛛（Araneus ventricosus)壶腹腺中扩增出鞭毛样丝蛋白基因（flagelldid-form silk protein gene),经1.5%琼脂糖凝胶电泳分离,WizardPCR Preps DNA Purification System回收后,将其克隆在pGEM-T载体中,经限制性核酸内切酶鉴定和核苷酸序列分析证实,构建的重组擀粒pSF1中含有蜂蛛鞭毛样丝蛋白基因,且含有3个重复序列。     

大腹园蛛(Araneus ventricosus)粗毒双向电泳及质谱分析

以大腹园蛛粗毒为材料,用固相pH梯度等电聚焦IPG(immobilized pH gradient)和SDS-PAGE(sodium dodecyl sulfate polyacrylamide gel electrophoresis)获得蛋白质组双向电泳图谱,经Bio-Rad公司的PDQUEST软件进行图像分析,检测到500个左右的蛋白质点．对其图谱的部分蛋白质点酶解后使用Micromass公司的ESI-Q-TOF进行了鉴定．得到了质量较好的MS／MS数据．然后将其在MS-Fit中的genepeptide数据库和Mascot的Swissprot中进行搜索从而对蛋白质点进行鉴定．目前初步获得5个组分的鉴定结果．     

大腹园蛛(Araneus ventricosus)12SrRNA基因片段序列分析

对大腹园蛛(Araneus ventricosus)的12SrRNA基因部分序列进行测定,得到276bp的碱基序列,其中A、T、G、C的含量分别为104bp(37.68％)、96bp(34.78％)、33bp(11.95％)、43bp(15.57％)。并尝试为我国蜘蛛目的分子系统学研究提供一些资料。     

大腹园蛛主壶腹腺蛛丝蛋白末端结构域的克隆表达

牵引丝(dragline silk)由主壶腹腺蛛丝蛋白(major ampullate spidroin, MaSp)组成,是蜘蛛丝中强度最好的丝,同时具有极佳的生物相容性和可降解性,因此引起研究者的研究热潮。目前关于大腹园蛛MaSp结构和成丝机理方面的研究甚少,限制了其仿生应用。本文以大腹园蛛牵引丝的组成蛋白质之一MaSp1为研究对象,通过锚定PCR的方法首次获取了大腹园蛛MaSp1 NT的完整编码基因,并对其进行了克隆、表达、纯化,产量可达60 mg/L;同时对该MaSp1的CT进行表达纯化,产量可达80 mg/L。另外,通过CD色谱分析了MaSp1 NT和CT的二级结构,结果表明二者的二级结构均以α-螺旋为主。上述结果为大腹园蛛MaSp1的结构和成丝机理研究奠定了基础。     

大腹圆蛛主壶腹腺cDNA文库构建和丝蛋白基因筛选

首次通过反转录-置换法和使用pUC18质粒成功构建大腹圆蛛（Araneus ventricosus)主壶腹腺（major ampullate gland)cDNA基因文库,并以鸟枪法从中筛选出具有典型重复结构的大腹圆蛛主壶腹丝蛋白cDNA基因AvF1,大小为1744bp,编码区为1572bp,编码氨基酸524个,分子量为42489.55Da,典型的重复结构为（GGP）nGGX。与现有已知的蛛丝蛋白基因中三带金蛛（Argiope trifas-ciata)鞭毛样丝基因（AtfF)有最高的同源性69.3%。大腹圆蛛主壶腹腺cDNA文库的构建和蛛丝蛋白新基因的克隆,为提供大腹圆蛛蛛丝蛋白基因背景和进一步研究蛛丝蛋白奠定了基础。     

大腹圆蛛Fosmid文库的构建及MaSp基因筛选方法的探讨

介绍了构建大腹圆蛛Fosmid基因组文库及牵引丝蛋白(MaSp)基因克隆筛选的全过程.采用改良CTAB法提取大片段基因组DNA,通过自主构建的电洗脱核酸回收装置分离回收30～40kbDNA片段,经补平磷酸化、与pCC2FOS载体连接、体外包装和转染EPI300TM-T1R,首次构建了无偏向性的大腹圆蛛Fosmid文库,其滴度为4.5×105cfu/mL,覆盖基因组倍数为10.以α-32P标记寡核苷酸探针对文库进行初步筛选,获得含MaSp基因的12个阳性克隆.该文库符合Fosmid文库的品质要求,为进一步筛选并研究大腹圆蛛MaSp基因序列奠定了基础.     

大腹园蛛鞭状腺蛛丝蛋白N端结构域的克隆表达及圆二色谱分析

鞭状腺蛛丝是6种蛛丝中延展性最好的丝,由鞭状腺蛛丝蛋白(FlSp)构成,具有极大的潜在应用价值。目前,有关FlSp的末端功能模块(NT和CT)编码基因的报道极少,且其结构和功能均尚未明确,这在一定程度上限制了鞭状腺蛛丝的仿生。现利用5′-RACE的方法,以大腹园蛛总RNA和基因组DNA为模板,首次获取了大腹园蛛FlSp NT模块(FlSp_A.v-NT)的完整编码基因,并对其成功进行了克隆、表达及纯化,产量可达60 mg/L;同时,利用圆二色谱(circular dichroism,CD)对FlSp_A.v-NT的二级结构进行了分析,结果显示其主要以α螺旋构象存在,这是首次对FlSp NT的二级结构进行探索,为后续FlSp NT结构功能的研究提供了材料,奠定了研究基础。     

大腹园蛛丝腺的氨基酸组成分析

通过解剖大腹园蛛,获得５种丝腺体,并对各丝腺蛋白进行了氨基酸组成分析和蛋白质相对分子质量测定,比较了不同丝腺体蛋白质组成的差异,发现不同丝腺体蛋白质氨基酸组成中Ｇｌｙ和Ｇｌｕ均有较高含量,而Ｓｅｒ的含量并不高,壶状腺中含有较高的Ｐｒｏ,而管状腺中含有较高的Ａｒｇ．同时发现不同丝腺体蛋白质的相对分子质量存在较明显差异,例如集合腺中不同相对分子质量的蛋白质分布较均匀,而在葡萄状腺中大分子质量的蛋白质明显高于小分子质量蛋白质．     

大腹园蛛大壶状腺丝蛋白-1基因部分cDNA的克隆和序列分析

大腹园蛛大壶状腺表达拖丝蛋白新基因的克隆, 为进一步研究蛛丝蛋白基因以及人工表达蛛丝蛋白提供参考依据。文章利用“通用方法”即反转录—置换法构建大腹园蛛(Araneus ventricosus)大壶状腺(Major ampullate gland) cDNA文库, 并筛选出具有典型重复结构的大腹园蛛大壶状腺丝蛋白-1部分cDNA序列AvMaSp1 (GenBank登录号: AY177203)。该部分序列大小为1 408 bp, 编码区为1 288 bp, 编码氨基酸429个, 预测分子量为34.07 kDa, 典型的重复结构为 (GA)nAm(GA)N, 与十字园蛛(Araneus diadematus)丝蛋白基因ADF-1 (GenBank登录号: ADU47853)同源关系最近, 一致性为75.0%。     

大腹园蛛丝腺及其细胞形态的初步观察

运用显微解剖和石蜡切片技术,我们首次对大腹园蛛Araneus ventricosus腹部的5种丝腺的形态进行了分离、拍照和切片观察.研究发现壶状腺腹腔较大,有多根纺管;梨状腺为多细胞腺体、成簇;集合腺有不规则的分支,纺管外附着小结节;葡萄状腺成簇.各类型丝腺腺体细胞明显可见,但未能明显见到不同丝腺腺体细胞的形态区别.同时也发现了几个存疑形态：壶状腺上附着的腺体、壶状腺下导管和壶状腺腺体细胞,它们可能与蜘蛛腺体的退化或发育等相关.     

Structural and Molecular Biology of the eye Lens Membrane

Abstract

The DNA double helix exhibits local sequence-dependent polymorphism at the level of the single base pair and dinucleotide step. Curvature of the DNA molecule occurs in DNA regions with a specific type of nucleotide sequence periodicities. Negative supercoiling induces in vitro local nucleotide sequence-dependent DNA structures such as cruciforms, left-handed DNA, multistranded structures, etc. Techniques based on chemical probes have been proposed that make it possible to study DNA local structures in cells. Recent results suggest that the local DNA structures observed in vitro exist in the cell, but their occurrence and structural details are dependent on the DNA superhelical density in the cell and can be related to some cellular processes.     

The Search for the Spatial and Electronic Requirements of a Drug

A new program called GAMMA (genetic algorithm for multiple molecule alignment) has been developed for the superimposition of several three-dimensional chemical structures. Superimposition of molecules and evaluation of structural similarity is an important task in drug design and pharmaceutical research. Similarities of compounds are determined by this program either based on their structural or their physicochemical properties by defining different matching criteria. These matching criteria are atomic properties such as atomic number or partial atomic charges. The program is based on a combination of a genetic algorithm with a numerical optimization process. A major goal of this hybrid procedure is to address the conformational flexibility of ligand molecules adequately. Thus, only one conformation per structure is necessary and the program can work even when only one conformation of a compound is stored in a database. The genetic algorithm optimizes in a nondeterministic process the size and the geometric fit of the overlay. The geometric fit of the conformations is further improved by changing torsional angles combining the genetic algorithm and the directed tweak method. The determination of the fitness of a superimposition is based on the Pareto optimization. As an application the superimposition of a set of Cytochrome P450c17 enzyme inhibitors has been performed.Electronic Supplementary Material available.     

Specific Features of Plastid Pigment Apparatus and Photosynthesis in the Leaves of Ephemeroid and Summer Plants as Related to Photoinhibition

The state of the pigment apparatus and potential photosynthesis (PP) was compared in the leaves of plants falling into two ecological groups, ephemeroids (three species) and summer plants (two species). For the first time, the organization of the plastid pigment apparatus was investigated in ephemeroids using the data on chlorophyll and carotenoid distribution between the major photosynthetic pools. The molar ratio between xanthophylls and chlorophyll in the light-harvesting complex of plastids in the ephemeroids (0.5 to 0.6) considerably exceeded that in the summer plants (0.3–0.4). By using salicylaldoxime, an inhibitor of the reverse reaction of the violaxanthin cycle, we were able to calculate the active pool of violaxanthin on its way to zeaxanthin. This pool was shown to amount to 85% of the sum total of xanthophylls of the violaxanthin cycle in the ephemeroid leaf plastids as compared to 60% in the summer species. Thus, potentially, the photosynthetic apparatus in the ephemeroid leaves is better provided with the pigments essential for photoprotective function and for maintaining a high photosynthetic rate under early spring conditions. Under chilling temperatures of 5–10°C and full insolation, PP in ephemeroids was as high as in the summer plants at 20°C.     

The Origin of Two Sexes Through Optimization of Recombination Entropy Against Time and Energy

Sexual reproduction in nature requires two sexes, which raises the question why the reproductive scheme did not evolve to have three or more sexes. Here we construct a constrained optimization model based on the communication theory to analyze trade-offs among reproductive schemes with arbitrary number of sexes. More sexes on one hand lead to higher reproductive diversity, but on the other hand incur greater cost in time and energy for reproductive success. Our model shows that the two-sexes reproduction scheme maximizes the recombination entropy-to-cost ratio, and hence is the optimal solution to the problem.     

The Mitochondrial Genome of Xiphinema americanum sensu stricto (Nematoda: Enoplea): Considerable Economization in the Length and Structural Features of Encoded Genes

The complete sequence of the mitochondrial genome of the plant parasitic nematode Xiphinema americanum sensu stricto has been determined. At 12626bp it is the smallest metazoan mitochondrial genome reported to date. Genes are transcribed from both strands. Genes coding for 12 proteins, 2 rRNAs and 17 putative tRNAs (with the tRNA-C, I, N, S1, S2 missing) are predicted from the sequence. The arrangement of genes within the X. americanum mitochondrial genome is unique and includes gene overlaps. Comparisons with the mtDNA of other nematodes show that the small size of the X. americanum mtDNA is due to a combination of factors. The two mitochondrial rRNA genes are considerably smaller than those of other nematodes, with most of the protein encoding and tRNA genes also slightly smaller. In addition, five tRNAs genes are absent, lengthy noncoding regions are not present in the mtDNA, and several gene overlaps are present. [Reviewing Editor: Dr. Yues van de Peer] F. Lamberti: Deceased, 2004     

Optimality modelling and quantitative genetics as alternatives to study the evolution of foraging behaviours in insect herbivores.

Summary Although the evolution of large-scale dispersal has received considerable attention, we know very little about how natural selection influences foraging behaviours in herbivorous insects. Host-selection behaviours and within-habitat movements jointly determine foraging behaviours, since host selection affects the allocation of time spent on a particular host versus moving between these hosts. However, host selection is generally a labile trait, whose expression is influenced by the physiological state of the forager and hence, by characteristics of the habitat. We discuss how the quantitative genetic concepts can be used to study the evolution of such labile behaviours. Since host responses depend on the physiological state of the forager, it is argued that the state of the forager must be explicitly considered when estimating the additive genetic basis of host-selection behaviours. The lability of foraging behaviours increases the difficulty of measuring the fitness consequence of variation in the foraging phenotype in specific habitats. Therefore, it may be difficult to rely exclusively on quantitative genetic methods to test hypotheses about adaptive change in foraging behaviours across different habitats. We provide a novel approach based on optimality modelling to calculate the fitness consequence of variation in the foraging phenotype across different habitats. This method, in conjunction with quantitative genetics, can be used to test hypotheses concerning the evolution of foraging behaviours.