| 2006年09月14日 Nature中英文摘要 | | 点击： 作者： 来源： 时间： 2006-11-11 本站论坛 |
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Volume 443 Number 7108 pp121-244 (14 September 2006)
September 14, 2006
封面故事：太阳发光度的变化
太阳能量输出（或发光度）的微小变化因其对气候变化的意义而引起人们的注意和争论。这种变化源自11年的太阳黑子周期中日面的暗结构(黑子)和亮结构（光斑）。1978年以来，科学家可以用卫星对这些结构进行准确追踪，并且发现它们的变化为0.07%。Foukal等人对我们在了解太阳发光度变化及其对地球上能量平衡的影响方面所取得的最新进展进行了评述，他们得出结论认为，自17世纪以来的太阳变亮不大可能对气候变化产生明显影响。与太阳紫外线和磁化等离子体输出相关的更具猜测性的气候变化尚不能排除，但由于涉及到复杂的相互作用因而也难以量化。本期封面所示为造成发光度变化的结构。（图片提供：Dan Kiselman/ Mats L?fdahl，瑞典1-米太阳望远镜2003年6月拍摄）
September 14, 2006
人类为什么与众不同？
什么使得人类与众不同？ 关于这个问题的一种比较遗传学方法揭示了一个候选基因，它在使人类之所以为人类方面起着部分作用。有趣的是，该基因在neocortex的胚胎发育过程中表达，而neocortex是大脑很多最复杂过程所发生的地点。该基因是在对直到黑猩猩/人类在进化过程中分道扬镳以前基本保持不变、但此后在人类中加速演化的非编码基因组区域所进行的一次搜寻中发现的。作为人类这个分支中演化速度最快的基因组区域之一的一个区域，相应于一个以前没有被研究过的RNA基因，名叫HAR1。基因表达研究表明，该基因在妊娠的关键阶段活跃于被称为Cajal-Retzius的神经元中，而这个时候neocortex的很多神经细胞正在大脑内确定自己的功能。
September 14, 2006
两种多药物排出输送分子的晶体结构
多药物排出输送分子在癌症化疗中和在细菌感染的治疗中会引起严重问题。它们的生物学中一个令人困惑的问题是，一个单一的输送分子何以能够识别和输送范围如此广泛的、结构又不相同的化合物？ 两种很不相同的多药物排出输送分子的晶体结构的发表，帮助解开了这个谜团。在第一项研究中，AcrB（一种来自大肠杆菌的多药物排出输送分子）的结构被确定出来。组成它的三个亚单元是在输送周期中的不同阶段被捕捉到的：基质结合之前、基质结合阶段和排出之后。庞大的多药物结合包通过多点结合处理多种基质。在另一项研究中，来自金黄色葡萄球菌(S.aureus)的一种由ATP驱动的多药物排出输送分子的结构被确定出来。这一“ABC”家族的输送分子的临床意义在于这样一个事实：它们催化在癌症治疗中所用的各种不同细胞毒性化合物的排出。该结构（在其中输送分子处于面向外的构型）是人类同类结构的一个有用模型，也许可以启发研究人员去合理设计以干涉在化疗中所用药物的排出为目标的药物。
September 14, 2006
最遥远、最古老的星系
本期Nature上186页所描述的星系在目前来说也许是最遥远、从而也是已知最古老的星系。在红移值为z~6的地方发现了大量星系样本，但在更早时候所做的探测往往是不确定的和不可靠的。不过这一“新的”古老星系有一个z=6.96的光谱红移值，相应于“大爆炸”之后仅7.50亿年。它的光谱上一个Lyman-a发射线表明，当宇宙只有其现在年龄约6%的时候，活跃的恒星形成过程正在进行当中。这个星系是在利用安装在Mauna Kea山顶峰上的 Subaru Suprime-Cam望远镜进行一次搜索过程中发现的。从宇宙中的星系作为一个整体来看，同样的搜索工作在红移为z ≈7的地方发现了若干星系，它们只有红移为z=6.6处星系密度的18-36%。利用“哈勃太空望远镜”在红移为z~7-8处进行的另一次搜索星系的工作，只在z~7-8处发现了一个候选星系，而如果说在z~7 和 z~6之间的星系群中没有发生变化的话，在z~7-8处是本应发现10个星系的。对这一结果的最简单的解释是，宇宙只是太年轻，无法在z~7-8处通过小星系的分级合并而形成很多明亮的星系。
September 14, 2006
“磁畴壁”技术又现生机
几十年前，计算机使用被称为“磁泡记忆体”的装置，在这种装置中，信息被存储在“磁畴壁”（domain wall）（磁化方向从一个方向改变为另一个方向的一个区域）中。“磁畴壁”是由磁场来移动的，但由于这种本来很有吸引力的技术在可靠性和缩放性方面存在问题，它后来就失宠了。今天，一种全新的、用电流短脉冲来移动“磁畴壁”的新手段，使得纳米尺度的基于“磁畴壁”的装置具有了可行性。Thomas等人利用这一新体系来在非常短的时间尺度上移动铁磁线中的“磁畴壁”，办法是施加纳秒长度的脉冲。而且，他们还观察到一种“飞去来器”效应，即“磁畴壁”被赶出了它们的约束势之外，处在了电流脉冲的相反方向上。
September 14, 2006
第五相氧的精确结构
氧作为一种气体以及在化学中以一种结合态形式出现对我们都很重要，除此之外，它的固体形式也有有趣的性质。固体氧有六种晶体相，其中一种，即第五相尤其具有不寻常的性质。它是暗红色的，在红外波段吸收强烈，失去了在其他相所具有的磁序，而且在很大的压力范围内是稳定的。此前，第五相氧的精确结构自其于1979年被发现以来一直不为人们所知。单晶X-射线衍射数据显示，第五相氧为O8，是束缚在一个分子晶格中的4个O2组成的一个斜方六面体单元。
September 14, 2006
欧洲今后夏季极端气候的出现将更频繁
欧洲很多地方经历了一系列极不寻常的夏天，气候极端干热（(2003年）和湿冷（2002年和2005年）。气候模型预测，这种夏天今后将更频繁出现，但造成这种变化的机制却不是很清楚。现在，Seneviratne等人利用一个区域气候模型发现，气温和土壤水分（而不是大气环流的变化）之间的反馈，是所预测的中欧和东欧夏季气温变化增加的主要原因。该结果突现了陆地-大气相互作用在未来气候变化中的潜在作用。
September 14, 2006
p53蛋白两种作用之间的关系
p53蛋白是脊椎动物DNA损伤响应和肿瘤抑制的一个重要调控因子。总体上，这两种作用被认为是有因果关系的：p53通过对肿瘤细胞中的DNA损伤或基因组异常做出响应以及触发生长抑制或细胞凋亡来抑制肿瘤。现在，Christophoru等人利用一个能够可逆转换的内生p53小鼠模型，发现病理性的由p53诱导的对辐射的响应，与由p53调控的对由这种辐射所诱导的肿瘤的抑制无关。相反，此后恢复 p53可避免辐射的病理效应，但能进行更多的肿瘤抑制。这些数据表明，DNA损伤响应和肿瘤抑制是p53的两个没有联系的活动，每个是由不同的信号诱导的。在另一项实验中，研究人员得出了一个类似的结论。肿瘤抑制蛋白ARF的缺乏，被发现会消除小鼠中一个额外版本的p53的额外的癌症保护活性。这个结果又一次说明，致癌信号作用对于触发p53的保护很关键，而由于DNA损伤所造成的p53的激发对于肿瘤最后发育的影响要小一些。 在一篇News and Views文章中，Anton Burns分析了这些发现对于p53活性模型的意义。
Contents
Editorials
Whistleblowers in peril p121
The US Congress should reverse a pernicious removal of protection of federal employees.
doi:10.1038/443121a
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Flickers of consciousness p121
Brain scans are forcing researchers to reconsider the state of outwardly unresponsive patients.
doi:10.1038/443121b
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Resisting terrorism p122
Government agencies, stakeholders and fellow researchers need to support primate researchers.
doi:10.1038/443122a
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Top of pageResearch Highlights
Research highlights p124
doi:10.1038/443124a
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Correction p125
doi:10.1038/443125a
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Top of pageNews
Neutrinos make a splash in Italy p126
Long-awaited experiment comes online.
Nicola Nosengo
doi:10.1038/443126a
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Warning flag for ethics boards p127
Institutional review panels form wildly different judgements.
Jim Giles
doi:10.1038/443127a
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Journey to the birth of the Universe p128
Record-breaking galaxy found.
Jenny Hogan
doi:10.1038/443128a
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Biomedical research gets a fresh twist down on the farm p128
Lab for unconventional work opens its doors.
Gene Russo
doi:10.1038/443128b
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Snapshot: Women at work p131
Alison Abbott
doi:10.1038/443131a
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Extreme TB strain threatens HIV victims worldwide p131
South Africa outbreak may prove impossible to contain.
Emma Marris
doi:10.1038/443131b
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Sidelines p132
doi:10.1038/443132a
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'Vegetative' patient shows signs of conscious thought p132
Evidence of brain activity raises issues for neurologists.
Michael Hopkin
doi:10.1038/443132b
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News in brief p134
doi:10.1038/443134a
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Top of pageBusiness
Nanotech's big issue p137
Lack of regulation and risk assessment could hamper the nanotechnology sector. Virginia Gewin reports.
doi:10.1038/443137a
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Top of pageNews Features
Ornithology: Digging for dodo p138
No one has seen a dodo in three and a half centuries, but that hasn't stopped the bizarre speculation about this extinct bird. Henry Nicholls investigates whether recent excavations in Mauritius could reveal the real creature.
doi:10.1038/443138a
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Climate change: A cosmic connection p141
Physicists and climate scientists have long argued over whether changes to the Sun affect the Earth's climate? A cloud chamber could help clear up the dispute, reports Jeff Kanipe.
doi:10.1038/443141a
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Top of pageCorrespondence
Investigator-initiated trials are more impartial p144
Bradley C. Johnston and Sunita Vohra
doi:10.1038/443144a
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Biochar trials aim to enrich soil for smallholders p144
William I. Woods, Newton P. S. Falc?o and Wenceslau G. Teixeira
doi:10.1038/443144b
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Biochar and biofuels for a brighter future p144
M. H. B. Hayes
doi:10.1038/443144c
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Science networks spread throughout the Arab world p144
A. Abyad
doi:10.1038/443144d
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Top of pageBooks and Arts
Our place in the Multiverse p145
Was the appearance of a Universe that can support life inevitable?
Joseph Silk reviews Many Worlds In One by Alex Vilenkin
doi:10.1038/443145a
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Back on track p146
Ann S. Masten reviews Out of the Woods: Tales of Resilient Teens by Stuart T. Hauser, Joseph P. Allen and Eve Golden
doi:10.1038/443146a
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A mathematical tonic p147
Timothy Gowers reviews Dr Euler's Fabulous Formula: Cures Many Mathematical Ills by Paul Nahin
doi:10.1038/443147a
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Correction p147
doi:10.1038/443147b
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In Retrospect: A global vision p148
Alison Jolly reviews The Ecological Theatre and the Evolutionary Play by George Evelyn Hutchinson
doi:10.1038/443148a
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Top of pageNews and Views
Evolutionary biology: Human brain gene wins genome race p149
The differences in brain size and function that separate humans from other mammals must be reflected in our genomes. It seems that the non-coding 'dark matter' of genomes harbours most of these vital changes.
Chris P. Ponting and Gerton Lunter
doi:10.1038/nature05154
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Crystallography: Solid oxygen takes shape p150
Oxygen crystallizes into a sequence of structures, starting as an insulator at low pressure and becoming a superconductor at high pressure. The elusive structure of an intermediate phase has now been determined.
Burkhard Militzer and Russell J. Hemley
doi:10.1038/443150a
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Astronomy: Dawn after the dark age p151
The latest surveys provide evidence for one, maybe two, galaxies farther back in cosmic time than ever detected before. But does the fact that we don't see more mean these are the very first galaxies to be formed?
Richard McMahon
doi:10.1038/443151a
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Cancer biology: Can less be more for p53? p153
The tumour-suppressor protein p53 is often mutated in cancer. But it seems that p53 deficiency is not all bad, and inhibiting this protein might mitigate toxic side effects of chemotherapy and radiotherapy.
Anton Berns
doi:10.1038/443153a
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Quantum physics: Observing and the observed p154
Quantum mechanics states that the measurement process can fundamentally alter what is being measured. This 'back-action' has been observed on the macroscopic scale — in the vibrations of a tiny mechanical device.
Michael Roukes
doi:10.1038/443154a
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50 & 100 years ago p156
doi:10.1038/443156a
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Structural biology: The ins and outs of drug transport p156
Multidrug transporters provide cells with a defence against toxic chemicals, but they are also responsible for drug resistance. The structures of two such transporters reveal novel aspects of their mechanisms.
Shimon Schuldiner
doi:10.1038/443156b
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Entomology: To catch a bee p158
Helen Dell
doi:10.1038/443155a
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Obituary: James A. Van Allen (1914–2006) p158
Magnetospheric and space physicist, discoverer of the eponymous belts.
Donald A. Gurnett
doi:10.1038/443158a
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Top of pageBrief Communications
Tumour biology: Policing of oncogene activity by p53 p159
Oncogenes, rather than DNA damage, may provide the key signal to p53 to trigger tumour suppression.
Alejo Efeyan, Isabel Garcia-Cao, Daniel Herranz, Susana Velasco-Miguel and Manuel Serrano
doi:10.1038/443159a
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Top of pageBrief Communications Arising
Archaeology: Progress and pitfalls in radiocarbon dating pE3
Chris S. M. Turney, Richard G. Roberts and Zenobia Jacobs
doi:10.1038/nature05214
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Archaeology: Progress and pitfalls in radiocarbon dating (Reply) pE4
Paul Mellars
doi:10.1038/nature05215
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Top of pageReview
Variations in solar luminosity and their effect on the Earth's climate p161
P. Foukal, C. Fr?hlich, H. Spruit and T. M. L. Wigley
doi:10.1038/nature05072
Abstract | Full Text | PDF (740K)
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Top of pageArticles
An RNA gene expressed during cortical development evolved rapidly in humans p167
Katherine S. Pollard, Sofie R. Salama, Nelle Lambert, Marie-Alexandra Lambot, Sandra Coppens, Jakob S. Pedersen, Sol Katzman, Bryan King, Courtney Onodera, Adam Siepel, Andrew D. Kern, Colette Dehay, Haller Igel, Manuel Ares, Jr, Pierre Vanderhaeghen and David Haussler
doi:10.1038/nature05113
Abstract | Full Text | PDF (449K) | Supplementary information
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Crystal structures of a multidrug transporter reveal a functionally rotating mechanism p173
Satoshi Murakami, Ryosuke Nakashima, Eiki Yamashita, Takashi Matsumoto and Akihito Yamaguchi
doi:10.1038/nature05076
Abstract | Full Text | PDF (854K) | Supplementary information
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Structure of a bacterial multidrug ABC transporter p180
Roger J. P. Dawson and Kaspar P. Locher
doi:10.1038/nature05155
Abstract | Full Text | PDF (610K) | Supplementary information
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Top of pageLetters
A galaxy at a redshift z = 6.96 p186
Masanori Iye, Kazuaki Ota, Nobunari Kashikawa, Hisanori Furusawa, Tetsuya Hashimoto, Takashi Hattori, Yuichi Matsuda, Tomoki Morokuma, Masami Ouchi and Kazuhiro Shimasaku
doi:10.1038/nature05104
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Rapid evolution of the most luminous galaxies during the first 900 million years p189
Rychard J. Bouwens and Garth D. Illingworth
doi:10.1038/nature05156
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Cooling a nanomechanical resonator with quantum back-action p193
A. Naik, O. Buu, M. D. LaHaye, A. D. Armour, A. A. Clerk, M. P. Blencowe and K. C. Schwab
doi:10.1038/nature05027
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Oscillatory dependence of current-driven magnetic domain wall motion on current pulse length p197
Luc Thomas, Masamitsu Hayashi, Xin Jiang, Rai Moriya, Charles Rettner and Stuart S. P. Parkin
doi:10.1038/nature05093
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Observation of an O8 molecular lattice in the phase of solid oxygen p201
Lars F. Lundegaard, Gunnar Weck, Malcolm I. McMahon, Serge Desgreniers and Paul Loubeyre
doi:10.1038/nature05174
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Land–atmosphere coupling and climate change in Europe p205
Sonia I. Seneviratne, Daniel Lüthi, Michael Litschi and Christoph Sch?r
doi:10.1038/nature05095
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The tumour suppressor Hippo acts with the NDR kinases in dendritic tiling and maintenance p210
Kazuo Emoto, Jay Z. Parrish, Lily Yeh Jan and Yuh-Nung Jan
doi:10.1038/nature05090
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The pathological response to DNA damage does not contribute to p53-mediated tumour suppression p214
M. A. Christophorou, I. Ringshausen, A. J. Finch, L. Brown Swigart and G. I. Evan
doi:10.1038/nature05077
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Structure of the insulin receptor ectodomain reveals a folded-over conformation p218
Neil M. McKern, Michael C. Lawrence, Victor A. Streltsov, Mei-Zhen Lou, Timothy E. Adams, George O. Lovrecz, Thomas C. Elleman, Kim M. Richards, John D. Bentley, Patricia A. Pilling, Peter A. Hoyne, Kellie A. Cartledge, Tam M. Pham, Jennifer L. Lewis, Sonia E. Sankovich, Violet Stoichevska, Elizabeth Da Silva, Christine P. Robinson, Maurice J. Frenkel, Lindsay G. Sparrow, Ross T. Fernley, V. Chandana Epa and Colin W. Ward
doi:10.1038/nature05106
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Autophosphorylation at serine 1987 is dispensable for murine Atm activation in vivo p222
Manuela Pellegrini, Arkady Celeste, Simone Difilippantonio, Rong Guo, Weidong Wang, Lionel Feigenbaum and André Nussenzweig
doi:10.1038/nature05112
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Molecular identification of the CRAC channel by altered ion selectivity in a mutant of Orai p226
Andriy V. Yeromin, Shenyuan L. Zhang, Weihua Jiang, Ying Yu, Olga Safrina and Michael D. Cahalan
doi:10.1038/nature05108
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Orai1 is an essential pore subunit of the CRAC channel p230
Murali Prakriya, Stefan Feske, Yousang Gwack, Sonal Srikanth, Anjana Rao and Patrick G. Hogan
doi:10.1038/nature05122
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An intron with a constitutive transport element is retained in a Tap messenger RNA p234
Ying Li, Yeou-cherng Bor, Yukiko Misawa, Yuming Xue, David Rekosh and Marie-Louise Hammarskj?ld
doi:10.1038/nature05107
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Top of pageNaturejobs
Prospect
Prospects p239
The anniversary of Hurricane Katrina reminds all scientists of a valuable lesson: be prepared.
Paul Smaglik
doi:10.1038/nj7108-239a
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Postdocs and Students
When it's personal p240
Personal problems can overwhelm an already stressful young research career, but sound strategies can help you stay the course, counsels Kendall Powell
Kendall Powell
doi:10.1038/nj7108-240a
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Careers and Recruitment
Richard Granger, director, Neukom Institute for Computational Science, Dartmouth College, Hanover, New Hampshire p242
Richard Granger set to head up centre that combines his love of computers and neuroscience.
Virginia Gewin
doi:10.1038/nj7108-242a
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Coming home p242
Returning home to Croatia to conduct science required persistence and patience.
Livia Puljak
doi:10.1038/nj7108-242b
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Tables turned p242
Facing the reality of being a graduate-student supervisor.
Mhairi Dupré
doi:10.1038/nj7108-242c
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Top of pageFutures
The trial of Jeremy Owens p244
The memory lingers on.
Peter Roberts
doi:10.1038/443244a
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