Volume 444 Number 7116 pp123-242 (9 November 2006)November 09, 2006
封面故事：成年视网膜能够结合新的光受体细胞
光受体损失会在很多视网膜疾病中导致不可逆转的失明。试图通过向成年视网膜中移植大脑或视网膜干细胞来修复这种损伤的努力基本上都失败了，没有生成新的光受体，也几乎没有迹象表明移植的细胞能与视网膜神经元连接或恢复视力。现在，用小鼠做的一个实验表明，成年视网膜能够结合新的光受体细胞，前提是移植的细胞是处于某个特定发育阶段的专一的视杆前体细胞，是由转录因子Nrl（在本期封面照片中心位置所示细胞中标记为绿色，视网膜色素显示为红色）的表达定义的。这项研究为从胚胎或成年干细胞生成适合移植的细胞铺平了道路。这些发现还向一个被人们普遍接受的假设提出了挑战，该假设认为，未分异的细胞最适合CNS修复。
November 09, 2006
月球的内部是否平静
通过分析从月球上取回的样品，研究人员判断，月球上广泛的火山活动在距今大约32亿年前停止了，虽然最后的少量玄武岩喷发持续到了距今不到10亿年前，月球被普遍认为不受今天其内部过程的影响。然而，“阿波罗”和“月球勘探者”探测器都探测到了月球内部释放气体（氡）的证据。对似乎在距今只有几百万年之前被“刷新”的月球表面特征所做的一项新的分析表明，这种“刷新”可能是由从深层裂缝中突然逃逸、并离开地表的气体引起的。这种地方可能含有关于月球内部深层构造的线索，也是今后探索工作的理想候选地点。
November 09, 2006
喜马拉雅山区易发生地震的原因
印度次大陆在以每年约40毫米的速度向北插入亚洲，从而使青藏高原不断升高，使喜马拉雅山系变形，并引起一连串的地震。对新的和已有的测地数据所做的分析表明，控制喜马拉雅山大地震的应变累积地区向西藏延伸的程度超过我们以前的估计。西藏南部的影响可解释为什么最近发生一些较小地震的地区会发生大地震。
November 09, 2006
纤毛虫基因组完成测序
全基因组复制是极其强大的演化力量，而人们非常关注的是，这些事件中复制的基因发生了什么。现在，纤毛虫Paramecium tetraurelia的基因组序列已经测序完成，它的近4万个基因（它是一个基因非常丰富的基因组）表明，至少有三个连续的全基因组复制。由于基因顺序在Paramecium中保持得特别好，所以有可能对在每个事件中所复制的基因进行识别，从而为在复制之后不同时间的基因损失情况提供一个完整的画面。
November 09, 2006
Rhomboid蛋白的晶体结构已被确定
Rhomboid伽马分泌酶和相关膜蛋白专在膜内发挥作用：很多信号蛋白经过膜内蛋白水解而处于活性状态，而其他一些信号蛋白则转化成溶解性较差的、淀粉质的多肽片段。现在，Rhomboid的晶体结构已被确定，该结构显示了它是怎样利用来自膜外的水分子来解理嵌入在膜中的蛋白基质的。催化类似反应的其他蛋白也可能有这一机制。它们当中的一个，即Presenilin，所发生的突变与家族性阿尔茨海默氏症有关。
November 09, 2006
边界润滑的新的应用前景
经典的边界润滑在工程应用中很普遍，也被认为存在于生物系统中：通过确保摩擦发生在每个表面上由表面活性剂分子构成的边界层之间，而不是发生在基质本身之间，就可以减少磨损。现在，用浸在水中的涂有边界润滑剂的滑动表面所做的实验表明，相对于在干燥空气中的摩擦力而言，摩擦力可以减少两个数量级以上。这个机制可能涉及带电的端部基团的水合作用，这些端部基团随后可在它们附着在其上的表面上顺利滑动。这种新型边界润滑可用于研制润滑的人造植体以及用来开发关节问题的新的医学治疗方法。
November 09, 2006
气候变化的南北呼应
在南极洲Dronning Maud Land钻取的一个新的冰芯（这项工作是EPICA项目的一部分）因两个原因而显得特别。第一个原因是其地理位置，因为面对着南大西洋，所以它是与格陵兰冰芯记录直接相对应的第一个南极洲冰芯，两个地区都潜在地被“大西洋子午线逆转环流”所耦合。第二个原因是，因为相对于南极洲东部高原地区其他钻探点来说，这个冰芯的积累速度快，所以它所提供的记录的分辨率要高得多，并且还能利用CH4中的global signature来实质性地提高与格陵兰冰芯记录的同步水平。该新冰芯15万年的气候记录显示，不仅南极洲的大幅度变暖存在着一种“双极跷跷板”（bipolar seesaw）现象，而且对北半球的每次Dansgaard Oeschger事件来说在南极洲也都有相应事件发生。南半球的变暖程度线性依赖于北半球同时出现的冰退过程的持续时间，它为“双极跷跷板”概念提供了一个独立佐证。
November 09, 2006
C3b的X-射线结构
本期Nature上三篇论文报告了对C3b所做的首次X-射线结构分析（C3b是人补体C3的活性形式）。 补体系统是由血清蛋白和细胞表面受体构成的一个家族，能够识别病原体，并释放针对它们的免疫反应。C3蛋白的动力来源是一个硫酯基团：当被激发时，它与病原体上的一个受体结合，并将其标记为摧毁目标。主体细胞中还有类似的硫酯，所以C3硫酯必须受到严格控制。了解C3b活性形式的结构，是朝设计操控补体系统的治疗方法的目标所迈出的一步。研究人员已经发现，补体系统的不正确激发，与包括关节炎、哮喘、红斑狼疮、自免疫心脏病和多发性硬化等疾病有关。
November 09, 2006
Wza蛋白的三维结构
很多细菌都有一个外部的多糖囊，用来帮助它们在表面上寄生。作为寄主和病原体之间的一个接触点，这种多糖囊是疫苗和其他疗法的一个潜在作用目标。现在，研究人员确定了一种名为Wza的、负责将囊中的多糖从细菌里面向外转移的蛋白的三维结构。多数Wza处在里面的胞质膜和外面的细胞膜或外周胞质之间的空间中。该蛋白含有一个很大的中央空腔，多糖穿过这个空腔来输送。
November 09, 2006
四足动物耳和四肢的演化起源
从水中向陆地的演化转变是人们一直都感兴趣的问题，最近与这种转变有关的过渡性化石在加拿大的发现以及将以前被划分为鱼类的化石重新解释为四足动物（或近似于四足动物的动物）的研究结果，进一步激发了人们的这种兴趣。但陆地生命的历史还要更为久远一些。来自澳大利亚泥盆纪地层的、距今已有3.8亿年但却保存极为完好的Gogonasus鱼的化石，在很多方面都像鱼，但其耳和鳍却出乎意料地发达。所以，四足动物耳和四肢骨架的一些特征现在可以从鱼类那里找到根源了。
ContentsEditorials
Another one bites the dust p123
The hazards of seeking to implement reforms at universities with outstanding reputations have been demonstrated once again, this time in Switzerland.
doi:10.1038/444123a
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Correction or retraction? p123
Errors reported in this issue by authors of a Nature paper pose a dilemma about trust.
doi:10.1038/444123b
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Smart but lightweight p124
An imaginative innovation policy in Britain continues to be under-resourced.
doi:10.1038/444124a
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Top of pageResearch Highlights
Research highlights p126
doi:10.1038/444126a
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Top of pageNews
Telescope is no longer dish of the day p128
Arecibo in the firing line as US observatories face cuts.
Heidi Ledford
doi:10.1038/444128a
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Data handling causes image problem for top lab p129
Correction to 1993 paper gets physicists talking.
Geoff Brumfiel
doi:10.1038/444129a
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It's the junk that makes us human p130
'Non-coding' DNA may organize brain cell connections.
Erika Check
doi:10.1038/444130a
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Faculty forces president to quit Swiss role p130
Leading European university in turmoil.
Alison Abbott
doi:10.1038/444130b
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Power up your memory bank p133
A stimulating night's sleep improves recall.
Kerri Smith
doi:10.1038/444133a
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Telling the time p134
Geochronologists are pinning down dates in deep time better than ever before. Rex Dalton talks to the experts who are redrawing the details of Earth history.
doi:10.1038/444134a
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Sidelines p135
doi:10.1038/444135a
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News in brief p136
doi:10.1038/444136a
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Top of pageBusiness
A breed apart p137
The US Food and Drug Administration may soon approve the use of cloned livestock for food. But regulatory roadblocks aren't the only thing keeping clones off the menu, as Heidi Ledford reports.
doi:10.1038/444137a
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Top of pageNews Features
Radio astronomy: Dutch courage p138
Most astronomers head for remote mountain-tops or deserts to study the cosmos. Jenny Hogan meets a confident team set up on a patch of farmland in a crowded corner of mainland Europe.
doi:10.1038/444138a
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Infant pain: Does it hurt? p143
Working out whether premature babies feel pain has important implications for child development, says Jane Qiu.
doi:10.1038/444143a
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Top of pageCorrespondence
An open letter to Colonel Muammar al-Gaddafi p146
Richard J. Roberts and 113 fellow Nobel Laureates .
doi:10.1038/444146a
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Don't forget the steps that led physics to where it is p146
Antonino Zichichi
doi:10.1038/444146b
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Biodiversity definitions vary within the discipline p146
Alison Holt
doi:10.1038/444146c
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US scorn for treaties hasn't improved nuclear security p146
Sebastian Raupach
doi:10.1038/444146d
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Top of pageBooks and Arts
One culture? p147
We can gain a clearer picture of visual representation by crossing the divide between art and science.
Bart Kahr reviews Seen | Unseen: Art, Science and Intuition from Leonardo to the Hubble Telescope by Martin Kemp
doi:10.1038/444147a
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Exhibition: Sowing the seeds p148
Simon Mawer reviews Gregor Mendel: Planting the Seeds of Genetics
doi:10.1038/444148a
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Correction p148
doi:10.1038/444148b
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Exhibition: The ballerina within p149
Laura Spinney reviews Picasso XRAYS
doi:10.1038/444149a
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Easing the pain p149
John Carmody reviews The Worst of Evils: The Fight Against Pain by Thomas Dormandy
doi:10.1038/444149b
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Top of pageNews and Views
Cell biology: A clean energy programme p151
Mitochondria supply cells with energy, but in the process produce potentially damaging oxidants. It seems that a protein required to produce new mitochondria also protects against the resulting oxidative damage.
Toren Finkel
doi:10.1038/444151a
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Climate change: The south–north connection p152
A new ice-core record from Antarctica provides the best evidence yet of a link between climate in the northern and southern polar regions that operates through changes in ocean circulation.
Eric J. Steig
doi:10.1038/444152a
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Structural biology: Enzyme theory holds water p153
Intramembrane proteases have attracted much attention because of their biological and medical value. The first crystal structure of one of these enzymes begins to solve the mystery of how they work.
Matthew Freeman
doi:10.1038/nature05305
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Neurobiology: Right timing for retina repair p156
Transplants of photoreceptor cells offer hope for treating retinal disease. But getting the cells to make the right connections with the brain has been problematic. It seems the developmental stage of the cells may be the key.
Thomas A. Reh
doi:10.1038/444156a
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Physiology: Channelled pain p156
Lesley Anson
doi:10.1038/444156b
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Astronomy: A troupe of near dwarfs p158
Faint satellite galaxies of the Milky Way are being discovered that are dimmer than some of the Milky Way's star clusters. This finding poses a fundamental question: what are galaxies?
Sidney van den Bergh
doi:10.1038/444157a
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50 & 100 Years Ago p159
doi:10.1038/444159b
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Immunology: Exposure of an executioner p159
The complement C3 protein binds to pathogens, singling them out for execution by the immune system. Structural studies show how the chemical group responsible for this binding is exposed on activation.
Michael Carroll
doi:10.1038/nature05307
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Quantum physics: Information on heat p161
There is a fundamental quantum limit to heat flow, just as there is to electric current. This limit is independent of what carries the heat, and could also have a role in an unexpected quarter: information theory.
Keith Schwab
doi:10.1038/444161a
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Earth science: Isotopic hide and seek p162
Isotopes formed by the decay of radioactive nuclei provide evidence of how Earth was shaped in its infancy. But some decay products seem to be hidden — a finding that will revitalize a debate about Earth's interior.
Francis Albarède
doi:10.1038/444162a
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Top of pageBrief Communications
Mechanoluminescence: Light from sonication of crystal slurries p163
Light flashes sparked by acoustic shock waves far outshine those created by manual crushing.
Nathan C. Eddingsaas and Kenneth S. Suslick
doi:10.1038/444163a
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Human immunodeficiency viruses: SIV infection in wild gorillas p164
Fran Van Heuverswyn, Yingying Li, Cecile Neel, Elizabeth Bailes, Brandon F. Keele, Weimin Liu, Severin Loul, Christelle Butel, Florian Liegeois, Yanga Bienvenue, Eitel Mpoudi Ngolle, Paul M. Sharp, George M. Shaw, Eric Delaporte, Beatrice H. Hahn and Martine Peeters
doi:10.1038/444164a
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Top of pageArticles
Great Himalayan earthquakes and the Tibetan plateau p165
Nicole Feldl and Roger Bilham
doi:10.1038/nature05199
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Global trends of whole-genome duplications revealed by the ciliate Paramecium tetraurelia p171
Jean-Marc Aury, Olivier Jaillon, Laurent Duret, Benjamin Noel, Claire Jubin, Betina M. Porcel, Béatrice Ségurens, Vincent Daubin, Véronique Anthouard, Nathalie Aiach, Olivier Arnaiz, Alain Billaut, Janine Beisson, Isabelle Blanc, Khaled Bouhouche, Francisco Câmara, Sandra Duharcourt, Roderic Guigo, Delphine Gogendeau, Michael Katinka, Anne-Marie Keller, Roland Kissmehl, Catherine Klotz, France Koll, Anne Le Mouël, Gersende Lepère, Sophie Malinsky, Mariusz Nowacki, Jacek K. Nowak, Helmut Plattner, Julie Poulain, Françoise Ruiz, Vincent Serrano, Marek Zagulski, Philippe Dessen, Mireille Bétermier, Jean Weissenbach, Claude Scarpelli, Vincent Schächter, Linda Sperling, Eric Meyer, Jean Cohen and Patrick Wincker
doi:10.1038/nature05230
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Crystal structure of a rhomboid family intramembrane protease p179
Yongcheng Wang, Yingjiu Zhang and Ya Ha
doi:10.1038/nature05255
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Top of pageLetters
Lunar activity from recent gas release p184
Peter H. Schultz, Matthew I. Staid and Carlé M. Pieters
doi:10.1038/nature05303
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Single-mode heat conduction by photons p187
Matthias Meschke, Wiebke Guichard and Jukka P. Pekola
doi:10.1038/nature05276
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Boundary lubrication under water p191
Wuge H. Briscoe, Simon Titmuss, Fredrik Tiberg, Robert K. Thomas, Duncan J. McGillivray and Jacob Klein
doi:10.1038/nature05196
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One-to-one coupling of glacial climate variability in Greenland and Antarctica p195
EPICA Community Members and
doi:10.1038/nature05301
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An exceptional Devonian fish from Australia sheds light on tetrapod origins p199
John A. Long, Gavin C. Young, Tim Holland, Tim J. Senden and Erich M. G. Fitzgerald
doi:10.1038/nature05243
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Retinal repair by transplantation of photoreceptor precursors p203
R. E. MacLaren, R. A. Pearson, A. MacNeil, R. H. Douglas, T. E. Salt, M. Akimoto, A. Swaroop, J. C. Sowden and R. R. Ali
doi:10.1038/nature05161
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Spider toxins activate the capsaicin receptor to produce inflammatory pain p208
Jan Siemens, Sharleen Zhou, Rebecca Piskorowski, Tetsuro Nikai, Ellen A. Lumpkin, Allan I. Basbaum, David King and David Julius
doi:10.1038/nature05285
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Structure of C3b reveals conformational changes that underlie complement activity p213
Bert J. C. Janssen, Agni Christodoulidou, Andrew McCarthy, John D. Lambris and Piet Gros
doi:10.1038/nature05172
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Structure of C3b in complex with CRIg gives insights into regulation of complement activation p217
Christian Wiesmann, Kenneth J. Katschke, JianPing Yin, Karim Y. Helmy, Micah Steffek, Wayne J. Fairbrother, Scott A. McCallum, Lizette Embuscado, Laura DeForge, Philip E. Hass and Menno van Lookeren Campagne
doi:10.1038/nature05263
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The structure of complement C3b provides insights into complement activation and regulation p221
A. Abdul Ajees, K. Gunasekaran, John E. Volanakis, Sthanam. V. L. Narayana, Girish J. Kotwal and H. M. Krishna Murthy
doi:10.1038/nature05258
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Wza the translocon for E. coli capsular polysaccharides defines a new class of membrane protein p226
Changjiang Dong, Konstantinos Beis, Jutta Nesper, Anne L. Brunkan-LaMontagne, Bradley R. Clarke, Chris Whitfield and James H. Naismith
doi:10.1038/nature05267
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A functional RNAi screen for regulators of receptor tyrosine kinase and ERK signalling p230
Adam Friedman and Norbert Perrimon
doi:10.1038/nature05280
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Top of pageCorrigenda
Atomic-resolution chemical analysis using a scanning transmission electron microscope p235
N. D. Browning, M. F. Chisholm and S. J. Pennycook
doi:10.1038/nature05262
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Earthquakes triggered by silent slip events on Klauea volcano, Hawaii p235
Paul Segall, Emily K. Desmarais, David Shelly, Asta Miklius and Peter Cervelli
doi:10.1038/nature05297
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Top of pageErratum
Centrosome polarization delivers secretory granules to the immunological synapse p236
Jane C. Stinchcombe, Endre Majorovits, Giovanna Bossi, Stephen Fuller and Gillian M. Griffiths
doi:10.1038/nature05299
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Top of pageNaturejobs
Prospect
Prospects p237
Paul Smaglik
doi:10.1038/nj7116-137a
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Special report
Closing the deal p238
Sales and marketing jobs at pharmaceutical companies offer the opportunity to combine science with social skills and creative flair. Hannah Hoag investigates the pitch.
Hannah Hoag
doi:10.1038/444238a
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Career Views
Georgina Mace, director, Centre for Population Biology, Imperial College London, UK p240
Georgina Mace addresses conservation efforts as head of a population-biology centre.
Virginia Gewin
doi:10.1038/nj7116-240a
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The view from Russia p240
Russian science is slowly adapting to political change.
Mikhail Gelfand
doi:10.1038/nj7116-240b
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The path to a PhD p240
How I fell in love with plants on the way to a PhD.
Mhairi Dupré
doi:10.1038/nj7116-240c
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Highlights
Highlight: Francophone
doi:10.1038/nj0132
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Top of pageFutures
Making the sale p242
Give 'em the easy choice.
Fredric Heeren
doi:10.1038/444242a
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上一篇：2006年11月02日 Nature中英文摘要 下一篇：2005年01月14日 Science中文摘要
