13 October 2006 Vol 314, Issue 5797, Pages 220-323
迄今测出的最小的基因组
科学家最近测出的两个细菌基因组如此之简单和小，它们也许给自身的定位带来危机。日本和西班牙的研究小组测定了生活在其它生物内的"共生体"细菌基因组，其中一个可能将丧失它作为真正生物体的地位而成为其宿主细胞的一个部分，另一个看来正在走向灭绝。
Atshushi Nakabachi 和同事报告说，Carsonella ruddii是生活在吸食植物液昆虫身上的一种寄生细菌，它的基因组只有160个kb之长。过去的估计曾把最小的基因组定在400kb左右。虽然Carsonella基因组排得很满，有许多重叠的基因，而且几乎没有"废物"DNA，但是它没有许多被认为是生命不可缺少的基因。这些发现提出，Carsonella 也许进化成了昆虫细胞内的一个细胞器，宿主细胞补偿了缺失的基因功能。Vicente Pérez-Brocal 和同事报告，Buchnera aphidicola的基因组要大点，约为420kb。该细菌与其它几种细菌一样共生在一种蚜虫身上。与其它共生物种相比，B. aphidicola失去了许多能让它为宿主生存作出贡献的重要功能，这是好的共生体所需要做到的。其它的共生细菌看起来接管了这些功能。文章作者推测B. aphidicola 可能在走向灭绝。一篇相关的研究评述讨论了这两项研究。
简报：The 160-Kilobase Genome of the Bacterial Endosymbiont Carsonella, Atsushi Nakabachi, et al.
报告：A Small Microbial Genome: The End of a Long Symbiotic Relationship?, Vicente Pérez-Brocal, et al.
研究评述：The Bacterial World Gets Smaller, Siv G. E. Andersson
快速自旋的小行星对
具有两个部分的近地小行星1999 KW4也许在一次靠近太阳或地球飞行的激发下，正在快速地自旋。在现已发现的840个大的近地小行星中，28个是双体系统。双体系统通常在太空中比较常见，比如双星系统和行星-卫星系统。离我们近的小行星为了解双体系统的行为提供了一个机会。当最大的近地双体小行星1999 KW4于2001年5月从我们的地球旁边飞过时，研究人员通过将雷达发射到它们的表面，测量返回信号的强度和延迟，测绘了它的两个部分。Steven Ostro和同事现在展示了这些测绘努力的结果。小行星的主要部分Alpha由非坚固的碎石组成，而且以每2.8小时一周的速度沿自身的轴自转。该部分的小伴侣Beta比Alpha的形状长而且密度大。在另一篇报告中，Daniel Scheeres和同事模拟了该系统的轨道和旋转动力学。Alpha自旋的速度接近它的离散速度。文章作者提出，这个双体小行星也许来自一个碎石堆的前体小行星，在其一次靠近太阳或地球的飞行后被导致进入自旋状态。1999 KW4的轨道与地球的轨道相交，所以了解该小行星的快速自旋运动对可能的碰撞也许是重要的。
科学特快报告：Radar Imaging of Binary Near-Earth Asteroid (66391) 1999 KW4, Steven J. Ostro, et al.
科学特快报告：Dynamical Configuration of Binary Near-Earth Asteroid (66391) 1999 KW4, D. J. Scheeres, et al.
巨大的金矿沉积也许形成得很快
科学家对来自巴布亚新几内亚一个岩浆中的液体做了采样后提出，世界上最大的一个金矿也许是在5万年左右的时间内形成的。世界上大约一半的已知金矿来自热液矿石的沉积，是由超热的水从岩石流过时沉积在矿脉的。几十年来，研究人员一直想知道这种热流溶液中到底含有多少金子，其中的金子输运多快、如何沉积、来自何处。Stuart Simmons 和Kevin Brown利用巴布亚新几内亚Lihir 岛的Ladolam金矿的一个非同寻常的情况研究了这些问题，那里是世界上最大和最年轻的热液金沉积正在一个活跃的热液系统中发生的地方。由于热液体给采矿带来困难，当地的采矿业钻了许多地热井，为研究人员提供了采样主要来自死火山下面岩浆的深水的机会。Simmons 和Brown确定出这些液体的含金量比来自其他地热系统的液体要多，他们估计在Ladolam沉积中需要大约5.5年的时间就能使金子积累出来，这在地质时间的尺度上是相当短的。一篇Christoph Heinrich撰写的研究评述讨论了这个沉积是否会更快地形成。
报告：Gold in Magmatic Hydrothermal Solutions and the Rapid Formation of a Giant Ore Deposit, Stuart F. Simmons and Kevin L. Brown
研究评述：How Fast Does Gold Trickle Out of Volcanoes?, Christoph A. Heinrich
突变陪伴基因的治疗作用？
只在细胞表面表达的肿瘤特异分子是治疗癌症的单克隆抗体的理想靶标。研究人员一直在寻找肿瘤特异的抗原，但是这些抗原多数是细胞内部的突变蛋白，单克隆抗体看不到它们。Andrea Schietinger和同事发现，一个细胞表面的非突变的细胞膜蛋白能被转变为一个肿瘤特异的抗原。他们报告了导致这个转变的复杂路径。一个陪伴基因(Cosmc)的突变中止了一个糖基转移酶的活性，通常在将糖附加到蛋白上需要该酶。这个突变改变了细胞表面蛋白的碳水化合物结构，并导致一个能作为高度特异的、具有治疗作用的单克隆抗体靶标的肿瘤特异分子的产生。Cosmc 基因的突变在几种人类和小鼠的肿瘤中被发现过，意味着该路径也许能产生几种能作为诊断和治疗抗体靶标的肿瘤特异的抗原。
报告：A Mutant Chaperone Converts a Wild-Type Protein into a Tumor-Specific Antigen, Andrea Schietinger, et al.
从DNA损坏到细胞死亡
一项新研究提出了一个帮助将带有基因损坏的细胞送入自毁灭程序的机制。为了维持健康，带有DNA损伤的细胞必须在细胞周期中暂停，以便修复DNA或进入被称为“凋亡”的细胞自杀程序。DNA损伤部分地通过抑制CDK2的活性来激活一个停止细胞周期的信号机制。Haojie Huang和同事提出，CDK2不仅与细胞周期的控制机制有关，而且与细胞死亡的控制机制有关。在培养细胞中，CDK2修饰转录因子FOXO1。在带有大范围DNA损伤的细胞中，降低FOXO1的修饰使其能运动到细胞核，在那里它增强诱导凋亡的基因的表达。一篇相关的研究评述讨论了这些发现，指出它们也许能为细胞如何对癌症治疗比如辐射和化疗发生抵抗力提供线索。
报告：CDK2-Dependent Phosphorylation of FOXO1 as an Apoptotic Response to DNA Damage, Haojie Huang, Kevin M. Regan, Zhenkun Lou, Junjie Chen, and Donald J. Tindall
研究评述：Balancing Life-or-Death Decisions, Jiri Bartek and Jiri Lukas
激光作为化学反应的催化剂？
研究人员报告说，激光脉冲能起某些化学催化剂的作用。催化剂通过改变妨碍原子在分子中重新组合的能量壁垒来加快化学反应的速度。但是催化剂的发现是一个比较慢和困难的过程，而且一个化学反应的那个部分能被比较容易地改变也是有限的。Benjamin Sussman和同事显示，激光脉冲也许有朝一日能取代催化剂来引导某些化学反应的结果。通过施加一个准确控制的、高强度的红外激光场，文章作者能控制激化的溴化碘分子分裂成一个碘原子和一个溴原子的方法。具体地说，脉冲改变能量壁垒使其倾向于两个可能的结果中的一个。这个技术的一个优点是，通过简单的时间控制，它能针对反应路径中的所有部分。一篇相关的研究评述讨论了这些结果的意义。
报告：Dynamic Stark Control of Photochemical Processes, Benjamin J. Sussman, Dave Townsend, Misha Yu. Ivanov, and Albert Stolow
研究评述：Strong-Arming Molecular Dynamics, Herschel Rabitz
Contents
This Week in Science
Editor summaries of this week's papers.
Science 13 October 2006: 220.
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Editorial:
Funding Basic Agricultural Research
William H. Danforth
Science 13 October 2006: 223.
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Editors' Choice
Highlights of the recent literature.
Science 13 October 2006: 224.
|Full Text »
NetWatch
Best of the Web in science.
Science 13 October 2006: 229.
|Full Text »
Gordon Research Conferences
Science 13 October 2006: 314-322.
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Science Podcast
Science 13 October 2006: 323.
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NEW PRODUCTS
Science 13 October 2006: 323.
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News of the Week
GENOMICS: On Your Mark. Get Set. Sequence!
Elizabeth Pennisi
Science 13 October 2006: 232.
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NUCLEAR PROLIFERATION: North Korea's Bomb: Boom or Bust?
Richard Stone
Science 13 October 2006: 233.
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NOBEL PRIZE IN ECONOMICS: Laurels for Theories That Demystified Inflation, Unemployment, and Growth
Yudhijit Bhattacharjee
Science 13 October 2006: 235.
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NOBEL PRIZE IN CHEMISTRY: Solo Winner Detailed Path From DNA to RNA
Robert F. Service
Science 13 October 2006: 236.
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BIOMEDICINE: NIH Funds a Dozen 'Homes' for Translational Research
Jocelyn Kaiser
Science 13 October 2006: 237.
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STEM CELLS: California Stem-Cell Institute Unveils 10-Year Plan
Constance Holden
Science 13 October 2006: 237.
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ScienceScope
Science 13 October 2006: 235.
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Random Samples
Science 13 October 2006: 231.
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Newsmakers
Science 13 October 2006: 249.
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News Focus
FUSION REACTOR: ITER's $12 Billion Gamble
Daniel Clery
Science 13 October 2006: 238-242.
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FUSION REACTOR: How to Squeeze a Plasma
Daniel Clery
Science 13 October 2006: 239.
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BRIAN O'NEILL PROFILE: Trying to Lasso Climate Uncertainty
John Bohannon
Science 13 October 2006: 243-244.
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NEUROSCIENCE: Brain Evolution on the Far Side
Elizabeth Pennisi
Science 13 October 2006: 244-245.
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PUBLIC HEALTH: Gerberding Defends Her Transformation of CDC
Jocelyn Kaiser and Jennifer Couzin
Science 13 October 2006: 246-247.
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PARTICLE PHYSICS: Tidy Triangle Dashes Hopes for Exotic Undiscovered Particles
Adrian Cho
Science 13 October 2006: 248.
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Letters
This Week's Letters
Science 13 October 2006: 251.
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Cooperating over Water Issues in the Middle East
Eric Pallant
Science 13 October 2006: 251.
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What Happens to the Whistleblowers?
Rachel L. Ruhlen
Science 13 October 2006: 251-252.
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A Problem with Mentoring
Maryjane Selgrade
Science 13 October 2006: 252-253.
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Mice, Pain, and Empathy
Ernest Gwyn Jordan; and Jeffrey S. Mogil
Science 13 October 2006: 253.
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Corrections and Clarifications
Science 13 October 2006: 254.
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Books et al.
PLANETARY SCIENCE: How to Build Planets
Caleb A. Scharf
Science 13 October 2006: 255-256.
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ECOLOGY: Fighting Fire with Common Sense
Ted Steinberg
Science 13 October 2006: 256.
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Books Received
Science 13 October 2006: 256.
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Policy Forum
ECOLOGY: Enhanced: Millennium Ecosystem Assessment: Research Needs
Stephen R. Carpenter, Ruth DeFries, Thomas Dietz, Harold A. Mooney, Stephen Polasky, Walter V. Reid, and Robert J. Scholes
Science 13 October 2006: 257-258.
Summary »| Full Text »| PDF »| Supporting Online Material »|
Perspectives
GENETICS: The Bacterial World Gets Smaller
Siv G. E. Andersson
Science 13 October 2006: 259-260.
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APPLIED PHYSICS: Seeking the Ultimate Nanolaser
Susumu Noda
Science 13 October 2006: 260-261.
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CELL BIOLOGY: Balancing Life-or-Death Decisions
Jiri Bartek and Jiri Lukas
Science 13 October 2006: 261-262.
Summary »| Full Text »| PDF »|
GEOCHEMISTRY: How Fast Does Gold Trickle Out of Volcanoes?
Christoph A. Heinrich
Science 13 October 2006: 263-264.
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CHEMISTRY: Strong-Arming Molecular Dynamics
Herschel Rabitz
Science 13 October 2006: 264-265.
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CHEMISTRY: Quantum Chemistry of Complex Systems
David C. Clary
Science 13 October 2006: 265-266.
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Brevia
The 160-Kilobase Genome of the Bacterial Endosymbiont Carsonella
Atsushi Nakabachi, Atsushi Yamashita, Hidehiro Toh, Hajime Ishikawa, Helen E. Dunbar, Nancy A. Moran, and Masahira Hattori
Science 13 October 2006: 267.
Although densely packed with genes, the tiny genome of an insect symbiont lacks some genes for essential functions, suggesting that it may be evolving into an organelle.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Research Article
The Consensus Coding Sequences of Human Breast and Colorectal Cancers
Tobias Sjöblom, Siân Jones, Laura D. Wood, D. Williams Parsons, Jimmy Lin, Thomas D. Barber, Diana Mandelker, Rebecca J. Leary, Janine Ptak, Natalie Silliman, Steve Szabo, Phillip Buckhaults, Christopher Farrell, Paul Meeh, Sanford D. Markowitz, Joseph Willis, Dawn Dawson, James K. V. Willson, Adi F. Gazdar, James Hartigan, Leo Wu, Changsheng Liu, Giovanni Parmigiani, Ben Ho Park, Kurtis E. Bachman, Nickolas Papadopoulos, Bert Vogelstein, Kenneth W. Kinzler, and Victor E. Velculescu
Science 13 October 2006: 268-274.
Published online 7 September 2006 [DOI: 10.1126/science.1133427] (in Science Express Research Articles)
Sequence analysis of >13,000 genes in breast and colorectal tumors shows that almost 200, a surprisingly large number, can be mutated, complicating any simple classification.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Reports
Self-Assembly of CdTe Nanocrystals into Free-Floating Sheets
Zhiyong Tang, Zhenli Zhang, Ying Wang, Sharon C. Glotzer, and Nicholas A. Kotov
Science 13 October 2006: 274-278.
Sheets of cadmium telluride particles can be assembled in a solvent without the usual constraint provided by a template or patterned surface.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Dynamic Stark Control of Photochemical Processes
Benjamin J. Sussman, Dave Townsend, Misha Yu. Ivanov, and Albert Stolow
Science 13 October 2006: 278-281.
The induced electric field of a precisely timed infrared laser pulse can be used to adjust the energy landscape of a photochemical reaction and direct its outcome.
Abstract »| Full Text »| PDF »|
Coherent Dynamics of Coupled Electron and Nuclear Spin Qubits in Diamond
L. Childress, M. V. Gurudev Dutt, J. M. Taylor, A. S. Zibrov, F. Jelezko, J. Wrachtrup, P. R. Hemmer, and M. D. Lukin
Science 13 October 2006: 281-285.
Published online 14 September 2006 [DOI: 10.1126/science.1131871] (in Science Express Reports)
Electron spins of a nitrogen vacancy in diamond are coupled to the nuclear spins of surrounding carbon atoms, allowing both to be manipulated for information processing.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Rapid Early Development of Circumarctic Peatlands and Atmospheric CH4 and CO2 Variations
Glen M. MacDonald, David W. Beilman, Konstantine V. Kremenetski, Yongwei Sheng, Laurence C. Smith, and Andrei A. Velichko
Science 13 October 2006: 285-288.
Expansion of northern peatlands beginning during the last deglaciation explains the early Holocene peak in atmospheric methane levels and slight drop in carbon dioxide levels.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Gold in Magmatic Hydrothermal Solutions and the Rapid Formation of a Giant Ore Deposit
Stuart F. Simmons and Kevin L. Brown
Science 13 October 2006: 288-291.
Fluids emanating from a magma beneath Papua New Guinea contain enough gold to demonstrate that one of the world's largest deposits was formed within only about 55,000 years.
Abstract »| Full Text »| PDF »|
Cellular and Subcellular Structure of Neoproterozoic Animal Embryos
James W. Hagadorn, Shuhai Xiao, Philip C. J. Donoghue, Stefan Bengtson, Neil J. Gostling, Maria Pawlowska, Elizabeth C. Raff, Rudolf A. Raff, F. Rudolf Turner, Yin Chongyu, Chuanming Zhou, Xunlai Yuan, Matthew B. McFeely, Marco Stampanoni, and Kenneth H. Nealson
Science 13 October 2006: 291-294.
X-ray imaging of the internal structures of Late Precambrian embryos implies that they were stem-group metazoans having already evolved sophisticated methods of differential cell division.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
CDK2-Dependent Phosphorylation of FOXO1 as an Apoptotic Response to DNA Damage
Haojie Huang, Kevin M. Regan, Zhenkun Lou, Junjie Chen, and Donald J. Tindall
Science 13 October 2006: 294-297.
The death of cells with damaged DNA results in part from altered localization of a transcription factor, triggered by a cell cycle protein.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Tissue Geometry Determines Sites of Mammary Branching Morphogenesis in Organotypic Cultures
Celeste M. Nelson, Martijn M. VanDuijn, Jamie L. Inman, Daniel A. Fletcher, and Mina J. Bissell
Science 13 October 2006: 298-300.
As the treelike mammary gland develops, branches form at geometrically defined positions where the concentration of inhibitory growth factors is minimal.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Tandem Riboswitch Architectures Exhibit Complex Gene Control Functions
Narasimhan Sudarsan, Ming C. Hammond, Kirsten F. Block, Rüdiger Welz, Jeffrey E. Barrick, Adam Roth, and Ronald R. Breaker
Science 13 October 2006: 300-304.
Multiple untranslated RNA sequences can occur in series upstream of genes to create complex genetic switches that are regulated by metabolites rather than proteins.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
A Mutant Chaperone Converts a Wild-Type Protein into a Tumor-Specific Antigen
Andrea Schietinger, Mary Philip, Barbara A. Yoshida, Parastoo Azadi, Hui Liu, Stephen C. Meredith, and Hans Schreiber
Science 13 October 2006: 304-308.
A mutation alters the glycosylation pattern of a membrane protein, converting it to a tumor-specific antigen that could be a therapeutic target for cancer therapy.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Herpes Simplex Virus Encephalitis in Human UNC-93B Deficiency
Armanda Casrouge, Shen-Ying Zhang, Céline Eidenschenk, Emmanuelle Jouanguy, Anne Puel, Kun Yang, Alexandre Alcais, Capucine Picard, Nora Mahfoufi, Nathalie Nicolas, Lazaro Lorenzo, Sabine Plancoulaine, Brigitte Sénéchal, Frédéric Geissmann, Koichi Tabeta, Kasper Hoebe, Xin Du, Richard L. Miller, Bénédicte Héron, Cyril Mignot, Thierry Billette de Villemeur, Pierre Lebon, Olivier Dulac, Flore Rozenberg, Bruce Beutler, Marc Tardieu, Laurent Abel, and Jean-Laurent Casanova
Science 13 October 2006: 308-312.
Published online 14 September 2006 [DOI: 10.1126/science.1128346] (in Science Express Reports)
Although multiple genes are generally thought to control an individual's resistance to infection, only one gene determines susceptibility to a herpesvirus.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
A Small Microbial Genome: The End of a Long Symbiotic Relationship?
Vicente Pérez-Brocal, Rosario Gil, Silvia Ramos, Araceli Lamelas, Marina Postigo, José Manuel Michelena, Francisco J. Silva, Andrés Moya, and Amparo Latorre
Science 13 October 2006: 312-313.
An aphid symbiont with a small genome has lost most metabolic functions, suggesting that it may soon be subsumed by another, more competent symbiont.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
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