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Nature Contents 30 March 2006 (Vol. 440 pp.581-714)
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[自然要览] （选自英国Nature杂志，2006年3月30日出版） 封面故事：星系演化的高分辨率数值模拟 The evolution of galaxies from primeval irregulars to present-day ellipticals 星系形成被认为是通过气体团块和恒星之间的一系列合并进行的。此前，在高红移处观 测到的遥远明亮天体（所观测到的是它们在100亿年前的情形）与今天的星系之间的关 系一直不确定，因为一直没有可能非常详细地模拟那些气体的演化。现在，一项超高分 辨率的数值模拟研究，已经成功对早期的不规则星系的形成以及它们随后向椭圆形星系 的演化进行了模拟。具体来说，该模型可解释椭圆形星系在一个完全没有碰撞的过程中 是如何由高红移星系（被称为Lyman-break星系）演化而来的。本期封面图片所示为3亿 年之后的星系演化的一个中间阶段。（Letter p. 644） 酿酒酵母蛋白之间相互作用的全面分析（Proteomics landmark） Proteome survey reveals modularity of the yeast cell machinery 两个小组完成了对酿酒酵母（Saccharomyces cerevisiae）的蛋白之间相互作用的全面 分析。Gavin等人识别出了491种截然不同的蛋白复合物，它们与其他蛋白模块发生作 用，生成酵母的细胞机器。这项工作还生成了超过5000个新的酵母菌种，可供今后进行 分析。Krogan等人识别出了547个复合物，每个平均涉及4.9个蛋白分子。很多酵母蛋白 是在演化中保留下来的，所以这两项重要的普查分析工组对于人类生物学的很多方面也 将是有意义的。（Articles pp. 631, 637） 土星环中观测到直径100米的小卫星（Propelled into the limelight） 100-metre-diameter moonlets in Saturn's A ring from observations of 'propeller' structures 土星的环系统主要由半径在几厘米至10米之间的无数冰粒组成，理论工作者预测，在这 些冰粒和两个两公里大小的小卫星“潘”和“达佛涅斯”之间存在一组直径在40米至 120米之间的小卫星。这些小卫星太小，“卡西尼”探测器上的照相机无法看到。但现 在直径100米的小卫星已被间接观测到，它们表现为土星环中的螺旋桨形状的扰动。这 些明亮的特征比土星环周围区域亮度大二到三个等级。到目前为止已经观测到4个这样 的小卫星，但它们所代表的小卫星群的数量有可能达到数百万个。（Letter p. 648; News and Views） 获取物质结构信息的新方法（Know the score） Ab initio determination of solid-state nanostructure 了解和设计新材料，关键是要知道它们的原子的排列方式。这个信息最常见的是通过X- 射线晶体学方法获得的，但该方法要求在材料中存在周期性重复的结构单元，而很多重 要的纳米材料没有规则的重复。为了克服这个问题，来自密执安州立大学的一个小组开 发了一种新方法，该方法利用由X-射线或中子衍射数据确定的原子间距离来获知材料的 结构。它利用两个距离几何算法来预测结构：一种是Liga算法，它的灵感来自足球联赛 中的升降级；另一种是“遗传”算法，其线索来自交配方式。（Letter p. 655; News and Views） “绿胡子理论”所存在的问题（How green is your beard?/ A not-so-close shave） Altruism through beard chromodynamics 利他主义的演化（尤其是在面向非同胞时）是演化生物学上的一个谜。然而，如果能够 轻易辨认出利他主义者的话，对此现象就可能容易解释一些。显然，最简单的识别系统 是一个明显的、可遗传的标签。一个绿色的胡子就可以承担此任。已经有若干例关于人 类相互接触中的“绿胡子效应”的报道，尽管胡子本人和绿色往往都没有反映在报道 中。这一解释所存在的一个问题是，一个基因编码所有三个功能（利他主义、标签功能 和识别功能）是不大可能的。根据模拟结果，Jansen 和van Baalen又发现了这一理论 所存在的另一个问题：即使绿胡子基因具有选择优势，利他主义按照以前的假设也是不 稳定的。但他们补充说，如果很多胡子颜色共存的话，利用识别机制所进行的合作的演 化可能性会更大。（Letter p.663） 推断基因组内容的方法（The cart before the horse?） Chance and necessity in the evolution of minimal metabolic networks 人们经常会读到利用基因组序列数据来推断一种生物怎样生存的论文，不常见的是本期 Nature上报告的一组科学家所采用的方法，他们为一组具有类似生活方式的相关的生物 生成了基因网络，并利用这些网络来推断该组生物中另一成员的基因内容。以大肠杆菌 的基因组为出发点，他们预测出了Buchnera（一种细胞内共生体，具有一个内容大大减 少的基因组）的代谢方式，该细菌是从大肠杆菌的一个祖先演化来的。这项工作对于寻 找一个“最小的基因组”的工作有参考价值，而且已经表明，所谓的“非必需基因”的 概念可能是谬误的，因为一个基因在变化中的基因组背景下可以很容易变成必需的基 因。（Letter p.667） 人类第15号染色体的分析结果（Zody AKE） Analysis of the DNA sequence and duplication history of human chromosome 15 对人类第15号染色体所做的分析表明，该染色体是高度分段复制的。该染色体复制的不 寻常之处是，它们集中在两个遥远的区域，而不是沿染色体分布。其中一个区域包括可 引起Prader-Willi 和 Angelman综合症的基因删除。复制的绝大部分都有一个共同的祖 先，可以追溯到同一个起源事件。（Letter p. 671） 聪明程度与大脑皮层发育的关系（Bright prospects） Intellectual ability and cortical development in children and adolescents 这里是一个肯定有争议的问题：由智商测试测出的智力水平与儿童和少年的物理大脑发 育之间的关系。现在，一项对307位典型的、处在从儿童到青少年发育时期（大致在6岁 至19岁之间）的研究对象所做的跟踪研究表明，聪明的孩子在任何一个年龄都不会因为 有更多或更少大脑灰质而变得更聪明。相反，智力与皮层成熟的连续过程中的不同方面 有关。具体来说，大脑皮层厚度的变化轨迹，而不是皮层厚度本身，才与智力有关。聪 明的孩子大脑皮层弹性特别好，皮层增加有一个最初的加速和延长阶段，而在青少年早 期又有一个同样充满活力的皮层变薄过程。（Letter p. 676; News and Views） 清醒时也能做梦（While you were awake） Reverse replay of behavioural sequences in hippocampal place cells during the awake state 在睡眠过程中，大鼠海马体已知能重现清醒时所发生的一系列活动。一项对绕着一个跑 道跑动、进食和梳理打扮的大鼠所做的新的研究工作表明，情景重现在清醒状态也反复 出现，行为序列是按相反次序重现的。关于空间学习的理论以前曾解释过反向重现为什 么可能是有用的。在清醒状态的重现也许还可部分解释为什么学习事件如果在时间上间 隔开来、而不是聚在一起的话会更好，为什么过度活跃会引起学习问题，以及为什么仅 仅处于清醒状态和保持休息就能帮助学习。（Letter p. 680; News and Views） 蛔虫的“自身感受”（Once more with feeling） A C. elegans stretch receptor neuron revealed by a mechanosensitive TRP channel homologue “自身感受”是我们的日常生活所必需的。例如，我们依靠“自身感受”来“感觉”我 们的身体在空间的位置，来引导我们的胳膊和腿应该伸出去多少。对蛔虫所做的一项研 究表明，该生物在运动过程中利用“自身感受”来控制其身体的姿势和位置。这需要一 个单一的“自身感受”神经元和一个在该神经元中发挥作用的机械传感离子通道。蛔虫 的这种神经元在功能上与人类肌梭和高尔基腱器官类似，后者是控制胳膊和腿运动的重 要器官。这些结果表明，“自身感受”的基本原理在蛔虫和人类之间是在演化上保留下 来的，也表明蛔虫可以成为研究“自身感受”及其相关的人类疾病的一种有价值的模型 生物。（Letter p. 684） 一种控制硅积累的水稻基因被发现(Silicon rice) A silicon transporter in rice 硅是地壳和土壤中第二种最丰富的元素，对植物生长是有益的，可帮助它们克服不同形 式的压力。它对水稻的高产稳产尤其重要。现在，研究人员发现了一种控制硅积累的水 稻基因，即Lsi1。该基因永久性地表达在根部，对其活性的抑制可减少硅的吸收。这是 首次关于高等植物中一种硅运输基因的报告，因为有些植物不能积累足够数量的硅，所 以该发现有可能为培育抗压力作物提供策略。（Letter p. 688） 抑制INK4/ARF位点活性的目标 Oncogenic activity of Cdc6 through repression of the INK4/ARF locus INK4/ARF位点编码三个肿瘤抑制因子，其活性在人类癌症中是经常被抑制的。现在， Gonzalez等人在INK4/ARF位点上识别出了一个可能的DNA复制起源，它能调控转录沉寂 作用，如当复制蛋白Cdc6在某些人类肿瘤中过度表达时。这说明Cdc6在人类癌症中是抑 制INK4/ARF活性的另一个目标。（Letter p. 702） |
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木虫 (正式写手)
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---------------------- NEWS AND VIEWS ---------------------- Ecology: Green and pleasant trials In the 1980s, a large lake -- Lago Guri -- was created as part of a hydroelectric project in Venezuela. Islands in the lake have enabled ecologists to test a fundamental hypothesis in their discipline. Peter D. Moore http://www.nature.com/nature/journal/v440/n7084/full/440613a.html Planetary science: Saturn's bared mini-moons Propeller-shaped structures seem to reveal the presence of moonlets, about 100 metres in diameter, embedded in Saturn's rings. This discovery adds to our picture of how the rings formed and are evolving. Frank Spahn and Jurgen Schmidt http://www.nature.com/nature/journal/v440/n7084/full/440614a.html Neuroscience: Rewinding the memory record How does the brain store sequences of experience? Clues come from brain recordings of rats running along a track. The animals' memories seem to be consolidated in an unexpected way as they rest between runs. Laura L. Colgin and Edvard I. Moser http://www.nature.com/nature/journal/v440/n7084/full/440615a.html 50 & 100 years ago http://www.nature.com/nature/journal/v440/n7084/full/440616a.html Quantum metrology: Size isn't everything From probing living cells under a microscope to scanning the heavens for gravity waves, the limitations of precision measurements constrain our capacity to discover more about the world. But what exactly are those limits? Samuel L. Braunstein http://www.nature.com/nature/journal/v440/n7084/full/440617a.html Materials science: Nanostructures in a new league Aperiodic materials do not surrender details of their structure as readily as do their crystalline counterparts. The latest computational solution to this problem brings aspects of /`the beautiful game/' into play. John J. Rehr http://www.nature.com/nature/journal/v440/n7084/full/440618a.html X-Ray imaging: Soft focus Ed Gerstner http://www.nature.com/nature/journal/v440/n7084/full/440619a.html Cognitive science: Brain development and IQ If intelligence is partly determined by our genes, how does brain development relate to IQ? An attempt to answer this question measures the size of the outer layer of the brain, the cortex, with surprising results. Richard Passingham http://www.nature.com/nature/journal/v440/n7084/full/440619b.html Environmental chemistry: Boiling up an acid plume Tim Lincoln http://www.nature.com/nature/journal/v440/n7084/full/440620a.html ---------------------- BRIEF COMMUNICATIONS ---------------------- Biopolymers: Shape memory in spider draglines The torsional properties of spider silk add to its list of remarkable physical credentials. Olivier Emile, Albert Le Floch and Fritz Vollrath Abstract: http://www.nature.com/nature/journal/v440/n7084/abs/440621a.html Article: http://www.nature.com/nature/journal/v440/n7084/full/440621a.html ---------------------- REVIEW ---------------------- Eukaryotic evolution, changes and challenges T. Martin Embley and William Martin Abstract: http://www.nature.com/nature/jou ... bs/nature04546.html Article: http://www.nature.com/nature/jou ... ll/nature04546.html ---------------------- ARTICLES ---------------------- Proteome survey reveals modularity of the yeast cell machinery Anne-Claude Gavin et al. Abstract: http://www.nature.com/nature/jou ... bs/nature04532.html Article: http://www.nature.com/nature/jou ... ll/nature04532.html Global landscape of protein complexes in the yeast Saccharomyces cerevisiae Nevan J. Krogan et al. Abstract: http://www.nature.com/nature/jou ... bs/nature04670.html Article: http://www.nature.com/nature/jou ... ll/nature04670.html ---------------------- LETTERS ---------------------- The evolution of galaxies from primeval irregulars to present-day ellipticals A simulation of galaxy formation that follows evolution from the earliest stages of formation through to the point where the resulting galaxy is in its final form as a present-day elliptical. Masao Mori and Masayuki Umemura Abstract: http://www.nature.com/nature/jou ... bs/nature04553.html Article: http://www.nature.com/nature/jou ... ll/nature04553.html 100-metre-diameter moonlets in Saturn's A ring from observations of ‘propeller’ structures Four longitudinal double-streaks in an otherwise bland part of Saturn's mid-A ring have been observed. It seems that embedded moonlets approximately 40 to 120 metres in diameter cause these ‘propeller’-shaped perturbations to arise. Matthew S. Tiscareno, Joseph A. Burns, Matthew M. Hedman, Carolyn C. Porco, John W. Weiss, Luke Dones, Derek C. Richardson and Carl D. Murray Abstract: http://www.nature.com/nature/jou ... bs/nature04581.html Article: http://www.nature.com/nature/jou ... ll/nature04581.html Controlled multiple reversals of a ratchet effect Using vortices trapped inside a superconductor that repel each other it can be demonstrated that particle-particle interactions can lead to multiple drift reversal of a ratchet effect, very different from the single particle behaviour. Clecio C. de Souza Silva, Joris Van de Vondel, Mathieu Morelle and Victor V. Moshchalkov Abstract: http://www.nature.com/nature/jou ... bs/nature04595.html Article: http://www.nature.com/nature/jou ... ll/nature04595.html Ab initio determination of solid-state nanostructure Two novel algorithms for nanostructure reconstruction from precise unassigned interatomic distances makes sub-angstrom resolution structure solution of nanomaterials possible. P. Juhas, D. M. Cherba, P. M. Duxbury, W. F. Punch and S. J. L. Billinge Abstract: http://www.nature.com/nature/jou ... bs/nature04556.html Article: http://www.nature.com/nature/jou ... ll/nature04556.html Melting in the Earth's deep upper mantle caused by carbon dioxide By determining the solidus of carbonated peridotite at high pressure it was demonstrated that melting beneath mid-ocean ridges may occur at greater depths than usually assumed -- down to 330 kilometres or more. Rajdeep Dasgupta and Marc M. Hirschmann Abstract: http://www.nature.com/nature/jou ... bs/nature04612.html Article: http://www.nature.com/nature/jou ... ll/nature04612.html Altruism through beard chromodynamics Resolving the enigma of the evolution of altruism is helped along by models showing that the coexistence of many tags makes the evolution of cooperation using a recognition mechanism more likely. Vincent A. A. Jansen and Minus van Baalen Abstract: http://www.nature.com/nature/jou ... bs/nature04387.html Article: http://www.nature.com/nature/jou ... ll/nature04387.html Chance and necessity in the evolution of minimal metabolic networks Rather than using genome sequence data to make conclusions about how an organism lives, the reverse approach can be adopted -- using gene networks generated for a group of related organisms with similar lifestyles to infer the gene content of another member of the group. Csaba Pal, Balazs Papp, Martin J. Lercher, Peter Csermely, Stephen G. Oliver and Laurence D. Hurst Abstract: http://www.nature.com/nature/jou ... bs/nature04568.html Article: http://www.nature.com/nature/jou ... ll/nature04568.html Analysis of the DNA sequence and duplication history of human chromosome 15 An analysis of human chromosome 15 -- which is altered in Prader-Willi and Angelman syndromes -- reveals that it resembles a hall of mirrors, as it contains a number of sequence duplications throughout its length. The evolutionary events that may have led to the high number of duplications was also reconstructed. Michael C. Zody et al. Abstract: http://www.nature.com/nature/jou ... bs/nature04601.html Article: http://www.nature.com/nature/jou ... ll/nature04601.html Intellectual ability and cortical development in children and adolescents P. Shaw, D. Greenstein, J. Lerch, L. Clasen, R. Lenroot, N. Gogtay, A. Evans, J. Rapoport and J. Giedd Abstract: http://www.nature.com/nature/jou ... bs/nature04513.html Article: http://www.nature.com/nature/jou ... ll/nature04513.html Reverse replay of behavioural sequences in hippocampal place cells during the awake state David J. Foster and Matthew A. Wilson Abstract: http://www.nature.com/nature/jou ... bs/nature04587.html Article: http://www.nature.com/nature/jou ... ll/nature04587.html A C. elegans stretch receptor neuron revealed by a mechanosensitive TRP channel homologue Wei Li, Zhaoyang Feng, Paul W. Sternberg and X. Z. Shawn Xu Abstract: http://www.nature.com/nature/jou ... bs/nature04538.html Article: http://www.nature.com/nature/jou ... ll/nature04538.html A silicon transporter in rice Jian Feng Ma, Kazunori Tamai, Naoki Yamaji, Namiki Mitani, Saeko Konishi, Maki Katsuhara, Masaji Ishiguro, Yoshiko Murata and Masahiro Yano Abstract: http://www.nature.com/nature/jou ... bs/nature04590.html Article: http://www.nature.com/nature/jou ... ll/nature04590.html Regulation of cancer cell migration and bone metastasis by RANKL Cancer cells that express the receptor protein RANK migrate to bone tissue where the RANK ligand, RANKL, is found. This contributes to bone metastases and offers a potential therapeutic approach to prevent cancer metastases. D. Holstead Jones, Tomoki Nakashima, Otto H. Sanchez, Ivona Kozieradzki, Svetlana V. Komarova, Ildiko Sarosi, Sean Morony, Evelyn Rubin, Renu Sarao, Carlo V. Hojilla, Vukoslav Komnenovic, Young-Yun Kong, Martin Schreiber, S. Jeffrey Dixon, Stephen M. Sims, Rama Khokha, Teiji Wada and Josef M. Penninger Abstract: http://www.nature.com/nature/jou ... bs/nature04524.html Article: http://www.nature.com/nature/jou ... ll/nature04524.html Analysis of a RanGTP-regulated gradient in mitotic somatic cells A fluorescence resonance energy transfer biosensor called Rango enables examination of the Ran-importin-[beta] system in cells. Small changes in RanGTP concentration tip the balance between positive and negative mitotic regulators, thereby promoting spindle assembly and function. Petr Kal??b, Arnd Pralle, Ehud Y. Isacoff, Rebecca Heald and Karsten Weis Abstract: http://www.nature.com/nature/jou ... bs/nature04589.html Article: http://www.nature.com/nature/jou ... ll/nature04589.html Oncogenic activity of Cdc6 through repression of the INK4/ARF locus A putative DNA replication origin at the INK4/ARF locus -- which encodes three tumour suppressors -- has been identified that can mediate its transcriptional silencing. Susana Gonzalez, Peter Klatt, Sonia Delgado, Esther Conde, Fernando Lopez-Rios, Montserrat Sanchez-Cespedes, Juan Mendez, Francisco Antequera and Manuel Serrano Abstract: http://www.nature.com/nature/jou ... bs/nature04585.html Article: http://www.nature.com/nature/jou ... ll/nature04585.html |
2楼2006-04-02 14:22:04