Volume 445 Number 7127 pp459-566   (1 February 2007)

February 01, 2007
封面故事：美国飞天新计划：重返月球+造访火星

本期封面照片是“阿波罗-11”任务期间尼尔•阿姆斯特朗拍摄的，照片所示为Buzz Aldrin带着EASEP科研仪器前往该仪器的部署地点。三年前，在题为“The Vision for Space Exploration”的文件中，美国国家航空天局（NASA）介绍了关于太阳系探测活动的一个新框架，新的探测活动将像30多年前“阿波罗”时代那样再次令人振奋。新框架的执行情况如何?在该新框架中，优先执行的计划包括重返月球计划以及为首次人类飞向火星做准备等。在本期Nature上（第474页），Geoff Brumfiel报告了该项目前三年的进展情况。封面图片：NASA AS11-40-5942

 


February 01, 2007
一个涉及三个密切相关基因的气孔生物合成通道

气孔是植物的气体交换结构，是让植物能够征服大地的关键发明之一。地球上全部植物的气孔活动一起对全球碳和水循环有重要影响。所以，气孔生物合成通道的发现将有广泛意义。两个小组在本期Nature上报告，他们识别出一个涉及三个密切相关的基因的相继表达的通道，这三个基因分别是SPEECHLESS、MUTE 和 FAMA。这表明，三个密切相关的基本“螺旋-环-螺旋”（helix-loop-helix）蛋白的连续行动控制着气孔分异，这是一个与动物的细胞类型分异极为相似的机制。


February 01, 2007
TBPb的人类同源结构被发现

端粒（线性染色体的端部）受各种结合蛋白的保护。纤毛虫中一个重要的端粒结合复合体是TBPalpa/beta。人类有一个TBPa同源结构POT1，但此前TBPb在纤毛虫以外的生物中没有被发现。现在，两个研究小组各自独立地识别出，神秘莫测的 TBPb的人类同源结构为TPP1。令人吃惊的是，当POT1-TPP1复合体结合到端粒DNA上时，它并不抑制端粒酶的活性，而其他端粒结合蛋白却会抑制。相反，它会刺激端粒酶活性和核苷酸添加速率，即由核心端粒酶添加核苷酸的速率。


February 01, 2007
对“热木星”HD209458b的最新观测结果

“热木星”，即在距离非常近的轨道上绕其母恒星运行的太阳系外巨型行星，将改变我们关于什么是行星以及它们怎样形成的观点。尤其是编号为HD209458b的一颗“热木星”，它被发现有一个巨大的、逃逸的大气层，这个大气层形成了一个彗星一样的尾巴。“哈勃太空望远镜”对HD209458b的新的观测结果显示，其大气层中有一个很热的致密层，在这个致密层中，温度上升，大气膨胀，气体加速逃逸该行星。这一探测为研究太阳系外复杂的行星大气逃逸过程提供了一个新途径。


February 01, 2007
一个特殊类型的空穴QED体系

在空穴量子电动力学（QED）中，原子或量子点与单个光子发生强相互作用。最新研究工作表明，可以形成一个“强耦合”关系，在该耦合关系中，单个光子被吸收，并被重新发射很多次。Schuster等人建造了一个特殊类型的空穴QED体系，该体系植入在一个电路内。在这个体系中，一个超导量子位（qubit）与来自一个微波发射线的光子发生相互作用。在这一体系中可以形成一种新的作用关系，即强色散极限，在其中，单个光子对量子位有一个很大的效应，而从不会被吸收。这一发现为非破坏性计数空穴中所存在光子数量提供了可能性。该效应有可能用作量子位-光子条件逻辑的一个基础，这种逻辑是量子计算的一个要求。


February 01, 2007
能探测浓度低于100毫微微摩尔未标记抗体的传感器

半导体纳米线有可能用作高度灵敏的、高选择性的传感器，来探测低浓度的致病微生物，而不需要对所探测的病原体进行标记。实用微型传感器可用于诊断、国土安全和基础研究。当前的技术因各种原因尚未被广泛采用，其中包括将纳米尺度的设备集成进实用传感器中所存在的困难。现在来自耶鲁大学五个系的一个研究小组研究出解决这一问题的一个新方法。他们利用最新的（CMOS兼容的）系统制成了微型的、超灵敏的传感器，可探测浓度低于100毫微微摩尔的未标记的抗体，并且能够实时监测细胞免疫反应。


February 01, 2007
现代版麦克斯韦“思想实验”

在其1867年的经典的“思想实验”中，麦克斯韦设想了一个守卫着将两个充满气体的腔室分隔开的活门的小魔鬼。通过只允许快速运动的分子从左向右通过、只允许慢速运动的分子从右向左通过的方式，这个小魔鬼诱导了右腔室自然加热、左腔室自然冷却的现象。这种偏离平衡的现象是违反热力学第二定律的。来自爱丁堡大学（距麦克斯韦的出生地不远）化学学院的一个研究小组现在研制出一种分子“机器”，它能模仿麦克斯韦的小魔鬼是如何破坏平衡的。小魔鬼的这种分子化身是一种特殊设计的Rotaxane，即缠绕在一个中心轴上的一个分子环，中心轴上有这个分子环可以附着的结合点。以前的Rotaxane机器是通过扰乱它们的环结合模式来激发的，它们的环结合模式被扰乱后，会导致环在结合点之间来回运动，从而使体系回到平衡态。在这种新的Rotaxane机器中，关于环运动的信息被用来使该体系远离平衡态。但这里热力学第二定律并没有被违反，因为需要能量（能量是以光的形式提供的）来收集和传输分子信息。


February 01, 2007
一个演示物种间相互作用重要性的实验

生物膜是微生物群落的专门的生存环境，在这种环境中，它们通过一种由其自己分泌的细胞外聚合物材料与外界隔绝。这样形成的微生物垫曾在复杂性和生物多样性方面被与热带雨林相比。这种生物膜所承受的选择压力很可能要求各种细菌之间要有强烈的相互作用，而利用一个只含有两个物种（即土壤中的细菌Pseudomonas putida 和 Acinetobacter sp.）的简单群落所做的一个实验正好反映了这种相互作用关系有多么紧密。若以对两个物种都有利的方式改变该群落的物理结构，会导致其中一个物种的基因组发生一个简单的突变。在缺少一个伙伴的情况下，这种突变（发生在P. putida中）将是有害的。这一体系说明了物种间相互作用的重要性，并且对关于这些相互作用演化方式的研究工作也可能会有用。


February 01, 2007
TRPA1离子通道的激发机制

存在于痛觉神经元中的TRPA1离子通道会对有害的和刺激性的化合物做出反应，也会对寒冷做出反应。用小鼠做的基因剔除实验证实，TRPA1是一种生理上要求的痛觉传感器。如此多样的刺激何以激发TRPA1以前并不清楚，但Macpherson等人现在发现，TRPA1是被其半胱氨酸残体的共价修饰激发的。蛋白质被半胱氨酸活性试剂修饰并非不寻常，但这是第一次发现离子通道以这种方式被激发。TRPA1激发在对亲电性毒性和氧化性压力的响应中所起的作用也许是就可能发生的组织损伤向生物体发出警告。


February 01, 2007
与bicoid mRNA定位有关的特异性因子被发现

虽然bicoid mRNA（果蝇的前决定因子）是于1988年首次被定位的决定因子，但此前仍然不清楚它是怎样被定位在果蝇卵的前部的。现在，Uwe Irion 和 Daniel St Johnston已经识别出了这个神秘的特异性因子，它将RNA耦合到定位通道上，成为ESCRT-II复合物。ESCRT-II在对已经通过细胞内吞作用从细胞表面进入降解通道的蛋白质进行分类中起重要作用，并通过抑制生长因子受体来抑制肿瘤形成。但bicoid mRNA的定位是独立于内吞分类的，而且因为大鼠的ESCRT-II也结合RNA，所以mRNA定位中这一新颖的功能似乎在哺乳动物中被保留了下来。


Contents

Editorials
Brave blue world p459
Human spaceflight is no excuse for ignoring the home planet, which needs constant monitoring from space.

doi:10.1038/445459a

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Defence deficit p459
A public debate about renewing Britain's nuclear weaponry is undermined by excessive secrecy.

doi:10.1038/445459b

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A changing drug supply p460
Research cuts by the world's largest drug company reflect a challenging outlook for the industry.

doi:10.1038/445460a

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Top of pageResearch Highlights
Research highlights p462
doi:10.1038/445462a

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Top of pageNews
Blair under fire over Trident 'secrecy' p464
Government rebuffs expert advice on submarine fleet.

Jim Giles

doi:10.1038/445464a

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California institute woos NIH stem-cell chief p464
James Battey is in the frame for president's job.

Meredith Wadman

doi:10.1038/445464b

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Bush splashes out on ocean research p465
President offers marine science $140-million cash boost.

Emma Marris

doi:10.1038/445465a

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Infertility researchers target uterus transplant p466
Surgeons optimistic operations could succeed.

Helen Pearson

doi:10.1038/445466a

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Michigan lab axed as Pfizer cuts costs p466
Staff in shock as drug giant restructures research.

Meredith Wadman

doi:10.1038/445466b

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Sidelines p468
doi:10.1038/445468a

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Physicists plan search for the known unknowns p468
Experiments aim to force gravity into the equation.

Jenny Hogan

doi:10.1038/445468b

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Volcano gets choke chains to slow mud p470
Geophysicists offer concrete proposal to stem East Java eruption.

David Cyranoski

doi:10.1038/445470a

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News in brief p471
doi:10.1038/445471a

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Correction p471
doi:10.1038/445471b

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Top of pageBusiness
Display of flexibility p473
Physicists at the University of Cambridge are leading a revolution in how data can best be displayed. Katharine Sanderson reports.

Katharine Sanderson

doi:10.1038/445473a

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Top of pageNews Features
Space exploration: Where 24 men have gone before p474
Three years ago, President George W. Bush told NASA to return American astronauts to the Moon. Geoff Brumfiel reports on how far they have got.

doi:10.1038/445474a

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Reproductive medicine: The first cut p479
Extracting a cell from a budding human embryo can expose genetic defects, but does it actually help generate more healthy babies? Bruce Goldman investigates.

doi:10.1038/445479a

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Conservation science: Ground force p481
Is parachuting into the Amazonian jungle any way to save an ecosystem? One team of biologists thinks so. Thomas Hayden joined them on a trip to Peru to find out what they do.

doi:10.1038/445481a

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Top of pageCorrespondence
Research on Tasmanian bones raises a number of ethical questions p484
Jason Coombes

doi:10.1038/445484a

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Increased funding vital to competitiveness initiative p484
William Jeffrey

doi:10.1038/445484b

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Five-point plan to revive and reform Indian science p484
U. C. Lavania

doi:10.1038/445484c

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All sizes of needle in that overcrowded haystack p484
Neville W. Goodman

doi:10.1038/445484d

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Top of pageBooks and Arts
For better or for worse p485
Science must be applied carefully if we are to reap the benefits but minimize the risks.

Ian Wilmut reviews Times of Triumph, Times of Doubt: Science and the Battle for Public Trust by Elof Axel Carlson

doi:10.1038/445485a

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See also: Editor's summary


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Painting the whole picture? p486
Philip Ball reviews Visions of Nature: The Art and Science of Ernst Haeckel by Olaf Breidbach

doi:10.1038/445486a

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Drifting into art p487
doi:10.1038/445487a

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Top of pageEssay
Connections
A twenty-first century science p489
If handled appropriately, data about Internet-based communication and interactivity could revolutionize our understanding of collective human behaviour.

Duncan J. Watts

doi:10.1038/445489a

Full Text | PDF (170K)

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Top of pageNews and Views
Chemical biology: Sticky spices p491
The spiciness of foods such as horseradish is perceived through sensory neurons of the pain pathway. The lingering pungency of some such foods results from chemical modification of the channels that trigger these neurons.

Michael J. Caterina

doi:10.1038/nature05565

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Materials science: Synergy in a superlattice p492
Put two types of crystal together in one lattice, and the resulting material can have properties greater than the sum of those of its individual components. Until now, that's been a difficult trick to pull off on a large scale.

James R. Heath

doi:10.1038/445492a

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50 & 100 Years Ago p493
doi:10.1038/445493a

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Hydrology: Tropical rain recycling p495
The behaviour of water in the atmosphere is a poorly understood part of the hydrological cycle. Applying the principles of isotope chemistry to satellite data provides a powerful approach for improving the situation.

Thom Rahn

doi:10.1038/445495a

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Organic chemistry: Catalytic gold rush p496
Despite gold's reputation as an inert element, chemists have mined a rich seam of catalytic reactions that use this metal. The latest example stakes out gold's claim as a versatile catalyst.

Steven P. Nolan

doi:10.1038/445496a

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Developmental biology: Moonlighting at the pole p497
Which end of a fly embryo becomes the head is partly dictated by the accumulation of bicoid RNA at the anterior pole. The protein that amasses the RNA turns out to be an old acquaintance from a different context.

Tor Erik Rusten and Harald Stenmark

doi:10.1038/445497a

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Reproductive biology: Sperm alliance p499
Tim Lincoln

doi:10.1038/445499a

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Quantum physics: Photon lab in a circuit p500
Electrical circuits might be regarded as rather mundane pieces of classical engineering. But their electromagnetic fields are, like light, a quantum object whose energy comes in discrete units — photons.

Frank K. Wilhelm and Enrique Solano

doi:10.1038/445500a

Full Text | PDF (103K)

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Top of pageBrief Communications Arising
Biological scaling: Does the exception prove the rule? pE9
Brian J. Enquist, Andrew P. Allen, James H. Brown, James F. Gillooly, Andrew J. Kerkhoff, Karl J. Niklas, Charles A. Price and Geoffrey B. West

doi:10.1038/nature05548

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Biological scaling: Does the exception prove the rule? (Reply) pE10
Peter B. Reich, Mark G. Tjoelker, Jose-Luis Machado and Jacek Oleksyn

doi:10.1038/nature05549

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Biological scaling: Does the exception prove the rule? (Reply) pE11
Lars O. Hedin

doi:10.1038/nature05550

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Top of pageArticles
Termination of asymmetric cell division and differentiation of stomata p501
Lynn Jo Pillitteri, Daniel B. Sloan, Naomi L. Bogenschutz and Keiko U. Torii

doi:10.1038/nature05467

Abstract | Full Text | PDF (1,633K) | Supplementary information

See also: Editor's summary


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The POT1–TPP1 telomere complex is a telomerase processivity factor p506
Feng Wang, Elaine R. Podell, Arthur J. Zaug, Yuting Yang, Paul Baciu, Thomas R. Cech and Ming Lei

doi:10.1038/nature05454

Abstract | Full Text | PDF (1,024K) | Supplementary information

See also: Editor's summary


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Top of pageLetters
The signature of hot hydrogen in the atmosphere of the extrasolar planet HD 209458b p511
Gilda E. Ballester, David K. Sing and Floyd Herbert

doi:10.1038/nature05525

First paragraph | Full Text | PDF (289K) | Supplementary information

See also: Editor's summary


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Resolving photon number states in a superconducting circuit p515
D. I. Schuster, A. A. Houck, J. A. Schreier, A. Wallraff, J. M. Gambetta, A. Blais, L. Frunzio, J. Majer, B. Johnson, M. H. Devoret, S. M. Girvin and R. J. Schoelkopf

doi:10.1038/nature05461

First paragraph | Full Text | PDF (643K)

See also: Editor's summary | News and Views by Wilhelm & Solano


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Label-free immunodetection with CMOS-compatible semiconducting nanowires p519
Eric Stern, James F. Klemic, David A. Routenberg, Pauline N. Wyrembak, Daniel B. Turner-Evans, Andrew D. Hamilton, David A. LaVan, Tarek M. Fahmy and Mark A. Reed

doi:10.1038/nature05498

First paragraph | Full Text | PDF (1,289K) | Supplementary information

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A molecular information ratchet p523
Viviana Serreli, Chin-Fa Lee, Euan R. Kay and David A. Leigh

doi:10.1038/nature05452

First paragraph | Full Text | PDF (642K) | Supplementary information

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Importance of rain evaporation and continental convection in the tropical water cycle p528
John Worden, David Noone and Kevin Bowman and The Tropospheric Emission Spectrometer science team and data contributors

doi:10.1038/nature05508

First paragraph | Full Text | PDF (2,710K) | Supplementary information

See also: News and Views by Rahn


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Evolution of species interactions in a biofilm community p533
Susse Kirkelund Hansen, Paul B. Rainey, Janus A. J. Haagensen and Søren Molin

doi:10.1038/nature05514

First paragraph | Full Text | PDF (616K) | Supplementary information

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Transcription factor control of asymmetric cell divisions that establish the stomatal lineage p537
Cora A. MacAlister, Kyoko Ohashi-Ito and Dominique C. Bergmann

doi:10.1038/nature05491

First paragraph | Full Text | PDF (994K) | Supplementary information

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Noxious compounds activate TRPA1 ion channels through covalent modification of cysteines p541
Lindsey J. Macpherson, Adrienne E. Dubin, Michael J. Evans, Felix Marr, Peter G. Schultz, Benjamin F. Cravatt and Ardem Patapoutian

doi:10.1038/nature05544

First paragraph | Full Text | PDF (1,011K) | Supplementary information

See also: Editor's summary | News and Views by Caterina


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The twisted ion-permeation pathway of a resting voltage-sensing domain p546
Francesco Tombola, Medha M. Pathak, Pau Gorostiza and Ehud Y. Isacoff

doi:10.1038/nature05396

First paragraph | Full Text | PDF (5,027K) | Supplementary information


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Structure prediction for the down state of a potassium channel voltage sensor p550
Michael Grabe, Helen C. Lai, Monika Jain, Yuh Nung Jan and Lily Yeh Jan

doi:10.1038/nature05494

First paragraph | Full Text | PDF (562K) | Supplementary information


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bicoid RNA localization requires specific binding of an endosomal sorting complex p554
Uwe Irion and Daniel St Johnston

doi:10.1038/nature05503

First paragraph | Full Text | PDF (1,122K) | Supplementary information

See also: Editor's summary | News and Views by Rusten & Stenmark


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TPP1 is a homologue of ciliate TEBP- and interacts with POT1 to recruit telomerase p559
Huawei Xin, Dan Liu, Ma Wan, Amin Safari, Hyeung Kim, Wen Sun, Matthew S. O'Connor and Zhou Songyang

doi:10.1038/nature05469

First paragraph | Full Text | PDF (841K) | Supplementary information

See also: Editor's summary


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Top of pageNaturejobs
Prospect
Postdocs face crossroads. p563

Paul Smaglik

doi:10.1038/nj7127-563a

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Career Views
Christoph Borchers, director, University of Victoria–Genome BC Proteomics Centre, Victoria, British Columbia, Canada p564
Christoph Borchers takes over at Canadian proteomics centre.

Virginia Gewin

doi:10.1038/nj7127-564a

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Better offices, better postdocs p564
Sloan Foundation funds new postdoc offices.

Virginia Gewin

doi:10.1038/nj7127-564b

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Happily ever after? p564
Choosing a mentor can be excruciating.

Maria Ocampo-Hafalla

doi:10.1038/nj7127-564c

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Recruitment
Bias cut p566
Women, it seems, often get a raw deal in science — so how can discrimination be tackled?

Lutz Bornmann

doi:10.1038/nj7127-566a

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Highlights
Opportunities: The National Institutes of Health
doi:10.1038/nj0144

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