| 2005年09月08日 Nature中文摘要 | | 点击： 作者： 来源： 时间： 2006-11-11 本站论坛 |
|  | Volume 437 Number 7056 pp169-294
封面故事：一种细菌神经传输物质运输分子
一种与依赖于钠和氯的神经传输物质的运输分子有关的细菌蛋白的晶体结构已经被确定。在大脑中，这些运输分子利用电化学梯度来驱动血清素、多巴胺、伽马氨基丁酸和氨基乙酸等神经传输物质在神经键上的快速吸收，从而结束神经传输。来自非常喜欢高温的细菌Aquifex aeolicus的运输分子运送亮氨酸（白氨酸）穿过细胞膜。它的结构显示了钠离子和亮氨酸的结合点，同时还显示了物质到达这些结合点必需打开的“控制门”。关于该结构的知识对于药物设计的很多方面都是很重要的：这些运输分子是很多抗抑郁药物和很多被滥用的药物的作用目标，包括帕金森氏症和癫痫症在内的神经疾病都与这些分子丧失功能有关。
好斗的罗非鱼
“参与并不重要，获胜才重要”——这是对好斗的莫桑比克罗非鱼所做的一项研究得出的结论。这些鱼（指雄性）对一个对手、甚至对镜中的自己都会表现出好斗倾向。但在“虚拟”打斗中，由于打斗没有结果，所以其打斗的动作并不会诱发一次荷尔蒙反应（即在身体中循环的雄性激素增加），荷尔蒙反应只会发生在有胜负的真正大打斗中。这可能是一种适应机制，使个体在其一旦估计出其对手的相对打斗能力之后，能够做出一次荷尔蒙反应，来增强它们的社会地位。
行星与小行星的异同
有人认为奎波带天体2003 UB313是“第10颗行星”，而且关于“冥王星”是行星的争论还在进行中。这些都说明，关于行星与小行星之间是否存在一条明确界线的问题是非常具有现实意义的。对哈勃太空望远镜拍摄的已知最大的小行星的200多张图像所做的一项新的研究，支持认为如果二者之间存在分界线、那么该分界线也是很模糊的观点。Ceres具有比它大的多的行星的很多物理特点和一个相似的历史。它比我们的月球要小的多，但哈勃太空望远镜拍摄的图像表明，它是一个平坦的、椭圆形的天体，很可能是由一个石质核心与一个冰质地幔分离后形成的。与土星和木星的冰质卫星不同的是，Ceres是暗的，说明其地幔可能在一个薄的覆盖层或一个由石质材料构成的地壳之下。
Van Allen辐射带高能粒子的加速机制
Van Allen 辐射带是来自太阳风的高能粒子被地球的磁场束缚住的环绕地球的空间区域。这些粒子的高能量（数百万电子伏特）使得该区域对宇宙飞船构成威胁。更好地了解将这些粒子加速到如此高能量的机制，将使科学家更容易预测卫星所面临风险增大的周期，而最近的一次罕见的事件为验证当前模型提供了一个机会。2003年的“万圣节”太阳风暴破坏了GPS和通信卫星以及短波无线电信号和电网，在向南远至佛罗里达的地方引起了红色极光。在太空中，两个辐射带中靠外的一个被耗尽了，然后变得更靠近地球。电磁波被认为是将电子加速到高速度的主要过程，而不是以前所怀疑的径向散射。
大陆淡水入海量对沿海海洋生态系统的影响
大陆边缘地区对气候变化极为敏感，所以了解它们会怎样对极端温暖条件做出反应非常重要。白垩纪中期“温室”气候阶段赤道大西洋中生产力、海洋化学和碳循环的变化表明，河流的淡水入海量是沿海海洋生态系统中的一个重要因素。大陆淡水的高入海量导致海洋生产力发生很大变化，导致沿海海洋中缺氧。
土壤碳丢失可能跟气候变化有关
土壤释放的CO2与全球变暖之间存在一个正反馈的可能性，是气候研究中最有争议的问题之一。人们的担心是，气温升高可能会引起土壤储存的大量碳中有一些以温室气体CO2的形式被释放进大气中，导致气温的进一步升高和更多的CO2释放。到目前为止，关于这一反馈机制的证据都来自小规模的实验室实验和野外实验以及数学模拟。现在，来自英国国家土壤资源研究所和Rothamsted研究所的一个小组发表了一项全国性长期土壤监测研究的数据，这些数据显示，在过去25年间有大量碳丢失，而土地利用对碳丢失量几乎没有影响，说明碳丢失可能跟气候变化有关。
Prion蛋白的形式及其感染性
找到控制传染性海绵形脑病如“克-雅氏症”传播的方法的前景，部分取决于能否识别、然后定位携带这种疾病的Prion蛋白的感染性最强的形式。对受到操控的羊痒病Prion蛋白所进行的一项研究表明，由14至28个Prion蛋白分子组成的分子团是迄今感染性最强的，小于6个分子的分子团基本上没有感染性。这一发现对于阿尔茨海默氏症和帕金森氏症（以与Prion有关的淀粉质原纤维的沉积为特征）的治疗也可能具有参考价值。试图通过使这些大的蛋白团失去稳定性来缓解症状，反而可能会使症状加重，因为这样会产生虽然较小、但感染性更强的蛋白团。（Letter p. 257）本期Nature上有两篇论文对Prion蛋白和淀粉质原纤维的基础生物学问题进行了研究。研究表明，对酵母的成熟Prion蛋白进行改造，会导致表现型发生变化，但未必能导致在蛋白合成过程中发生蛋白折叠错误。这一结果对于Prion蛋白疾病的病理和治疗都具有参考意义。（Letter p. 262）对由核糖核酸酶-A得到的一种“人工设计的” 淀粉质原纤维所做的一项研究，显示了一种含有具有酶活性的、像是天然的分子的淀粉体。这一结果支持关于贝它-淀粉质结构的“拉链脊模型”（zipper-spine model）。
NOTCH1突变与动脉瓣钙化
在对同一家庭5代人的先天性心脏病所进行的一项研究中，研究人员发现了动脉瓣钙化（成年人心脏病的一个主要原因）的一个遗传基础。这种病在转录调控因子NOTCH1有一个突变的家庭成员中是明显的。该突变基因在转基因小鼠中表达时引起心瓣缺陷。NOTCH1突变以前曾在人类血癌中发现，但该研究是首次表明它在心脏发育中也扮演一个角色。
表皮细胞的更新
为了发挥其作为一个有效的物理屏障的功能，我们的皮肤形成了几层不断更新的表皮细胞。这一过程是怎样发生的一直不清楚，但以前用培养的皮肤细胞所做的研究表明，表皮底部的干细胞形成向皮肤表面迁移的新细胞。现在，对小鼠胚胎所做的研究表明，固定在表皮底部的原始干细胞具有进行非对称复制的新颖功能。它们产生一种“超底层细胞”，其中含有粘附分子和生长因子，该细胞是固定不变的；在其之上的是一种增殖能力很强的底层细胞，最适合分异。
本期目录：
Volume 437 Number 7056 pp169-294
Editorials
Small-minded government p169
Last week's debacle in New Orleans highlights failings not just in the Bush administration, but in how the United States chooses to govern itself.
doi: 10.1038/437169a
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Proteomics' new order p169
An international organization is finally bringing discipline to the study of cells' sets of proteins.
doi: 10.1038/437169b
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Endangered act p170
Efforts to reform the Endangered Species Act could harm America's most important conservation law.
doi: 10.1038/437170a
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Top of pageResearch Highlights
Research highlights p172
doi: 10.1038/437172a
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Top of pageNews
After the flood p174
Academic experts say they were all too aware of the devastation that would claim New Orleans and its surroundings in the wake of a fierce hurricane. Could they have done any more to convince politicians of the need to protect the city?
Tony Reichhardt, Erika Check and Emma Marris
doi: 10.1038/437174a
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Health centres and labs left reeling by Katrina p177
Hospital for New Orleans' poor hit hard.
Rex Dalton
doi: 10.1038/437177a
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Drug agency accused of political bias p179
Women's health director quits over 'morning after' pill delays
Meredith Wadman
doi: 10.1038/437179a
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Poles lose out as ozone levels begin to recover p179
Hole over Antarctica is third-largest recorded.
Quirin Schiermeier
doi: 10.1038/437179b
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Ecology is key to effective aid, UN told p180
Report recommends local management of natural resources.
Jim Giles
doi: 10.1038/437180a
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Budget plans hint at lean times ahead for Japanese research p181
Basic projects may face cutbacks.
Ichiko Fuyuno
doi: 10.1038/437181a
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Chernobyl: poverty and stress pose 'bigger threat' than radiation p181
Local communities suffer many effects of fall-out.
Valeska Stephan
doi: 10.1038/437181b
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News in brief p182
doi: 10.1038/437182a
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Top of pageNews Features
Stem-cell research: The rocky road to success p185
Tackling the legal and ethical minefield associated with human embryonic stem-cell research is not for the faint-hearted. Erika Check meets one man who is relishing the challenge.
doi: 10.1038/437185a
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Ornithology: A wing and a prayer p188
Sightings of the ivory-billed woodpecker, a bird believed extinct for 50 years, have fired the public's imagination. But is it really alive? Rex Dalton joins the team trying to save this elusive bird.
doi: 10.1038/437188a
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Top of pageBusiness
Fears rise over leaks of clinical trial results p191
Doctors accused of selling drug secrets to market analysts.
Virginia Gewin
doi: 10.1038/437191a
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In brief p191
doi: 10.1038/437191b
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Top of pageCorrespondence
Cuban science democratic and not tied to profit p192
Catherine Badgley and Ivette Perfecto
doi: 10.1038/437192a
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Bioweapons could kill more in one strike than guns p192
Michael C. Wendl
doi: 10.1038/437192b
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EURYI scheme aims to stop women disappearing p192
Neil Williams
doi: 10.1038/437192c
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EURYI: present procedure risks conflicts of interest p192
Gábor Lente
doi: 10.1038/437192d
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Top of pageBooks and Arts
In our own hands p193
Biotechnology is changing the world, but why do nations respond so differently?
Mark Cantley reviews Designs on Nature: Science and Democracy in Europe and the United States by Sheila Jasanoff
doi: 10.1038/437193a
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A scientist's life in Russia p194
Alan L. Mackay reviews About Science, Myself and Others by V. L. Ginzburg
doi: 10.1038/437194a
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Families behaving badly p195
Jonathan Wright reviews A Natural History of Families by Scott Forbes
doi: 10.1038/437195a
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Top of pageNews and Views
Structural biology: Fibres hinge on swapped domains p197
When proteins assemble themselves into fibres, there can be grave pathological consequences. Designing an otherwise soluble protein to make fibres provides a general mechanism for the construction process.
Andrew D. Miranker
doi: 10.1038/437197a
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Biological physics: Rare returns on lost effort p198
How does the size of a system affect its thermodynamic irreversibility? A deft experiment that observes the unfolding and refolding of a single molecule of RNA provides insights into the question at a small scale.
Wesley P. Wong and Evan Evans
doi: 10.1038/437198a
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Evolutionary genetics: Microarrays and species origins p199
Whole-genome arrays have been used to reveal small islands of genetic differentiation in Anopheles mosquitoes. Analysis of these regions will identify genes involved in the initial stages of speciation.
Roger Butlin and Cally Roper
doi: 10.1038/437199a
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Synthetic chemistry: Glycosylation with a twist p201
Nature has a whole battery of dedicated enzymes to make the complex links between sugar rings — how can synthetic chemists compete? An ingenious approach fills a big gap in the synthetic tool-kit.
Sabine L. Flitsch
doi: 10.1038/437201a
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50 & 100 years ago p202
doi: 10.1038/437202a
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Molecular physiology: Intimate contact enables transport p203
Sodium-coupled neurotransmitter transporters are essential for neurons to communicate. The high-resolution crystal structure of a bacterial relative hints at how this family of transporters works.
Baruch I. Kanner
doi: 10.1038/437203a
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Environmental science: Carbon unlocked from soils p205
Changes in climate and land use are implicated as the main factors in the large-scale loss of carbon from soils in England and Wales over the past 25 years. The same picture is likely to apply much more broadly.
E. Detlef Schulze and Annette Freibauer
doi: 10.1038/437205a
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Physical chemistry: Isn't it ionic p206
Magdalena Helmer
doi: 10.1038/437206a
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Top of pageBrief Communications
Behavioural endocrinology: No hormonal response in tied fights p207
Fish androgens may start to surge only when there seems to be a good chance of winning a contest.
Rui F. Oliveira, Luis A. Carneiro and Adelino V. M. Canário
doi: 10.1038/437207a
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Dynamical phenomena: Walking and orbiting droplets p208
Y. Couder, S. Protière, E. Fort and A. Boudaoud
doi: 10.1038/437208a
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Top of pageBrief Communications Arising
Malaria risk: Estimating clinical episodes of malaria pE3
Bernard L. Nahlen, Eline L. Korenromp, John M. Miller and Kenji Shibuya
doi: 10.1038/nature04178
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Malaria risk: Estimation of the malaria burden pE3
David R. Bell, Pernille Jorgensen, Eva Maria Christophel and Kevin L. Palmer
doi: 10.1038/nature04179
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Malaria risk: Estimating clinical episodes of malaria (reply) pE4
Robert W. Snow, Carlos A. Guerra, Abdisalan M. Noor, Hly Y. Myint and Simon I. Hay
doi: 10.1038/nature04180
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Top of pageArticles
Strategies for containing an emerging influenza pandemic in Southeast Asia p209
Neil M. Ferguson, Derek A.T. Cummings, Simon Cauchemez, Christophe Fraser, Steven Riley, Aronrag Meeyai, Sopon Iamsirithaworn and Donald S. Burke
doi: 10.1038/nature04017
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Crystal structure of a bacterial homologue of Na+/Cl--dependent neurotransmitter transporters p215
Atsuko Yamashita, Satinder K. Singh, Toshimitsu Kawate, Yan Jin and Eric Gouaux
doi: 10.1038/nature03978
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Top of pageLetters
Differentiation of the asteroid Ceres as revealed by its shape p224
P. C. Thomas, J. Wm. Parker, L. A. McFadden, C. T. Russell, S. A. Stern, M. V. Sykes and E. F. Young
doi: 10.1038/nature03938
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Wave acceleration of electrons in the Van Allen radiation belts p227
Richard B. Horne, Richard M. Thorne, Yuri Y. Shprits, Nigel P. Meredith, Sarah A. Glauert, Andy J. Smith, Shrikanth G. Kanekal, Daniel N. Baker, Mark J. Engebretson, Jennifer L. Posch, Maria Spasojevic, Umran S. Inan, Jolene S. Pickett and Pierrette M. E. Decreau
doi: 10.1038/nature03939
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Verification of the Crooks fluctuation theorem and recovery of RNA folding free energies p231
D. Collin, F. Ritort, C. Jarzynski, S. B. Smith, I. Tinoco, Jr and C. Bustamante
doi: 10.1038/nature04061
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Ionic colloidal crystals of oppositely charged particles p235
Mirjam E. Leunissen, Christina G. Christova, Antti-Pekka Hynninen, C. Patrick Royall, Andrew I. Campbell, Arnout Imhof, Marjolein Dijkstra, René van Roij and Alfons van Blaaderen
doi: 10.1038/nature03946
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Orbital forcing of Cretaceous river discharge in tropical Africa and ocean response p241
Britta Beckmann, Sascha Fl?gel, Peter Hofmann, Michael Schulz and Thomas Wagner
doi: 10.1038/nature03976
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Carbon losses from all soils across England and Wales 1978?2003 p245
Pat H. Bellamy, Peter J. Loveland, R. Ian Bradley, R. Murray Lark and Guy J. D. Kirk
doi: 10.1038/nature04038
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Geophysical evidence from the MELT area for compositional controls on oceanic plates p249
Rob. L. Evans, Greg Hirth, Kiyoshi Baba, Don Forsyth, Alan Chave and Randall Mackie
doi: 10.1038/nature04014
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The effect of migration on local adaptation in a coevolving host?parasite system p253
Andrew D. Morgan, Sylvain Gandon and Angus Buckling
doi: 10.1038/nature03913
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The most infectious prion protein particles p257
Jay R. Silveira, Gregory J. Raymond, Andrew G. Hughson, Richard E. Race, Valerie L. Sim, Stanley F. Hayes and Byron Caughey
doi: 10.1038/nature03989
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Prion protein remodelling confers an immediate phenotypic switch p262
Prasanna Satpute-Krishnan and Tricia R. Serio
doi: 10.1038/nature03981
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Amyloid-like fibrils of ribonuclease A with three-dimensional domain-swapped and native-like structure p266
Shilpa Sambashivan, Yanshun Liu, Michael R. Sawaya, Mari Gingery and David Eisenberg
doi: 10.1038/nature03916
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Mutations in NOTCH1 cause aortic valve disease p270
Vidu Garg, Alecia N. Muth, Joshua F. Ransom, Marie K. Schluterman, Robert Barnes, Isabelle N. King, Paul D. Grossfeld and Deepak Srivastava
doi: 10.1038/nature03940
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Asymmetric cell divisions promote stratification and differentiation of mammalian skin p275
Terry Lechler and Elaine Fuchs
doi: 10.1038/nature03922
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Interaction of phosphorylated c-Jun with TCF4 regulates intestinal cancer development p281
Abdolrahman S. Nateri, Bradley Spencer-Dene and Axel Behrens
doi: 10.1038/nature03914
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A mechanistic principle for proton pumping by cytochrome c oxidase p286
Kristina Faxén, Gwen Gilderson, Pia ?delroth and Peter Brzezinski
doi: 10.1038/nature03921
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Erratum: In situ multi-satellite detection of coherent vortices as a manifestation of Alfvénic turbulence p290
David Sundkvist, Vladimir Krasnoselskikh, Padma K. Shukla, Andris Vaivads, Mats André, Stephan Buchert and Henri Rème
doi: 10.1038/nature04144
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Erratum: Evasion of intracellular host defence by hepatitis C virus p290
Michael Gale, Jr and Eileen M. Foy
doi: 10.1038/nature04145
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Corrigendum: Action potential refractory period in ureter smooth muscle is set by Ca sparks and BK channels p290
T. Burdyga and Susan Wray
doi: 10.1038/nature04146
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Top of pageNaturejobs
Prospect
Breathing life into industry p291
Regional programme offers biotech training to life-science graduates
Paul Smaglik
doi: 10.1038/nj7056-291a
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Career Views
Brian Foster, European regional director, International Linear Collider's Global Design Effort, Oxford, UK p292
Physicist takes on large collider project
Janet Wright
doi: 10.1038/nj7056-292a
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Scientists & Societies p292
Young European scientists form research training networks
Alessandro Sartori
doi: 10.1038/nj7056-292b
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Graduate Journal: Dualities p292
Graduate learns to live with positives and negatives of her decisions
Karolina Tkaczuk
doi: 10.1038/nj7056-292c
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Top of pageFutures
Not at home to visitors p294
They're big, but they're not clever.
Janet Wright
doi: 10.1038/437294a
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