2006年4月28日 美国《科学》周刊312卷 第5773期
爱琴考古争议解决了？
部分地因为一棵被火山爆发而活埋的橄榄树的发现，多年来有关爱琴晚青铜时期年代的争议也许很快能得到解决。公元前2千年前后，有几个主要文化在爱琴海附近发展，后来这些文化成为古代近东和埃及贸易与文化的一部分。考古学家曾靠分析这些地方发现的文物之间的相似性把它们在不同时间段连接起来。比如，对古希腊文明有重要影响的克里特岛新宫殿文化（New Palace culture），与埃及的新王朝时期(New Kingdom period)有时间上的连接。但是自1970年代以来，来自这些地点的放射性碳年代测定表明，爱琴的新宫殿和其他时期，包括希腊本土的井墓时期和塞浦路斯重要的新沿海地点高度发展的时期，可能要早些。
在此之前，放射性碳数据中的不确定性使人们对这个地区的年表有争议。Sturt Manning和同事现在描述了大量的放射性碳年代测定，其结果跨越了300年的时间，这些数据表明一个更老的爱琴年表。帮助解决这个迷的一个关键发现是找到了一个如今属于希腊的岛上被该时期火山爆发活埋的一棵树。这次火山爆发产生了"古爱琴的庞培"，火山灰扩散到该地区不少的地方，为年代测定提供了一个重要的参照点。在一篇相关的简报中，Walter Friedrich和同事描述了这棵树的发现及其年代的测定，为火山爆发本身提供了直接和准确的年代。他们得出的结果与Manning小组的年表相符。这两篇文章使爱琴的记录提早了约100年。这意味着克里特岛新宫殿文化以及希腊和塞浦路斯那个时期的文化与埃及的第二中间时期看来是同时的，而不是在埃及新王朝之后。
报告：Chronology for the Aegean Late Bronze Age 1700-1400 B.C., Sturt W. Manning, et al.
简报：Santorini Eruption Radiocarbon Dated to 1627-1600 B.C., Walter L. Friedrich, et al.
机械的昆虫眼
研究人员报告说，一个新的机械复眼看上去很像昆虫的眼，而且工作的方式也差不多。这个眼的许多个透镜及其曲线的形状使它具有宽广的视野，以及超高速运动觉察和图像识别的能力。文章作者Ki-Hun Jeong 和同事说 ，用这类透镜的微型相机和运动传感器也许有医学、工业和军事的应用。昆虫的眼含有多个对着不同方向的名为"单眼(ommatidia)"成像单元。研究人员用柔性的聚合物来制造人工的单眼，每个单眼有一个透镜与管状的"波导"连接，波导将光引导到一个光电成像设备。然后，他们将这些单眼排放成一个半球形，朝着所有的方向。作者说，在所有的昆虫复眼中，蜜蜂的眼与这个新的机械眼最相像。
报告：Biologically Inspired Artificial Compound Eyes, Ki-Hun Jeong, Jaeyoun Kim, and Luke P. Lee
抗疟疾的野生蚊子
科学家在野生蚊子身上发现了一个天然的抗疟疾的基因线索，这也许能用于新的疟疾控制战略。有些野生蚊子在吸食了人类被疟疾原虫感染的血液后，将疟疾传染给他人。一项新研究提出，许多野生蚊子对疟疾原虫具有基因抵抗力，它们能杀死被感染血液中的寄生虫而不传播这些原虫。当野生蚊子吸食了来自马里人的被疟疾原虫天然感染的血液后，这些蚊子位于其名为"抵抗岛"的一小段染色体的基因保护蚊子不受疟疾原虫的感染。这个抵抗岛上的一个蚊子基因与植物和脊椎动物识别病原体的基因类似，而且似乎能在实验室中保护蚊子不受疟疾原虫的感染。这个国际小组的作者推测，易患并传播疟疾的蚊子也许其免疫系统有缺陷。
报告： Natural Malaria Infection in Anopheles gambiae Is Regulated by a Single Genomic Control Region, Michelle M. Riehle, et al.
真菌性制的极端转变
有些生活在土壤中的非致病霉菌被哺乳动物的肺吸入后，转变为致病的酵母，科学家现在发现了控制这个极端转变的基因。这项新研究的作者说，对控制"二态真菌"这类转变机制的进一步了解，也许对开发心的药物和疫苗有用。在美国，二态真菌每年能引起超过100万例感染，包括人类的肺炎。Julie Nemecek和同时发现，编码一对名为"组氨酸激酶"的蛋白复合体的基因，在几种二态真菌中能觉察出从土壤环境进入哺乳动物肺暖温环境的变化。这个古老的、进化保守的环境感应似乎参与控制很多真菌的特征，包括细胞壁和孢子的形成、以及毒性因子的表达。当真菌觉察到环境的变化后，比如从土壤进入人类肺脏，它们的性质会改变。
报告：Global Control of Dimorphism and Virulence in Fungi, Julie C. Nemecek, Marcel Wüthrich, and Bruce S. Klein
稻瘟病菌如何侵入水稻
稻瘟病是影响世界上水稻产量的最严重的周期性发作病害，现在一项新研究的作者对该真菌如何入侵水稻提供了线索。这个名为稻瘟病菌(Magnaporthe grisea)的致病真菌形成一个专门的、半球形的名为“附着器”的感染结构，该结构侵入水稻植物的叶和茎。文章作者揭示，这个致病真菌在能感染水稻之前，其中的个别细胞必须选择性地死亡。科学家得出结论，真菌病原体能在感染宿主时用自噬相关的细胞死亡来进行细胞分化和重构。他们还提出，真菌孢子的自噬细胞死亡也许能成为一种用来确定稻瘟病发生的发育“检查站”。
报告： Autophagic Fungal Cell Death Is Necessary for Infection by the Rice Blast Fungus, Claire Veneault-Fourrey, Madhumita Barooah, Martin Egan, Gavin Wakley, and Nicholas J. Talbot
观察纳米管的能量光谱
单壁碳纳米管是由具有半导体和金属性质的管形成的混合体，作为一个整体，人们不容区分出单个管的性质。现在，Matthew Sfeir和同事用两种不同的光谱学技术显现了单个纳米管的电子能量状态的具体变化和物理结构。该技术也许能用来预测微电子器件中某个纳米管如何工作。Sfeir和同事的试验证实了在半导体和金属纳米管中都有某种能量变化的出现，这些变化最早是在纳米管混合体中观察到的。
报告：Optical Spectroscopy of Individual Single-Walled Carbon Nanotubes of Defined Chiral Structure, Matthew Y. Sfeir, et al.
Contents
This Week in Science
Editor summaries of this week's papers.
Science 28 April 2006: 496.
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Editorial:
Re-Aim Blame for NIH's Hard Times
J. Michael Bishop and Harold Varmus
Science 28 April 2006: 499.
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Editors' Choice
Highlights of the recent literature.
Science 28 April 2006: 500.
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NetWatch
Best of the Web in science.
Science 28 April 2006: 505.
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NEW PRODUCTS
Science 28 April 2006: 601.
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News of the Week
ARCHAEOLOGY: New Carbon Dates Support Revised History of Ancient Mediterranean
Michael Balter
Science 28 April 2006: 508-509.
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STEM CELLS: Court Rules in Favor of California Stem Cell Institute
Jocelyn Kaiser
Science 28 April 2006: 509.
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SCIENTIFIC COMMUNITY: University Clears Chinese Biophysicist of Misconduct
Hao Xin
Science 28 April 2006: 511.
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PLANETARY SCIENCE: Simulation Suggests Peaceful Origin for Giant Planet's Weird Spin
Govert Schilling
Science 28 April 2006: 512-513.
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FRANCE: Chemist Claims Innocence to Spying Charge
Martin Enserink
Science 28 April 2006: 512.
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OCEANOGRAPHY: Korea and Japan Clash Over Surveys
Dennis Normile
Science 28 April 2006: 513.
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GENETICS: Parasite-Resistant Mosquitoes: A Natural Weapon Against Malaria?
Martin Enserink
Science 28 April 2006: 514.
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BIOMEDICAL RESEARCH: Bone Disease Gene Finally Found
Jennifer Couzin
Science 28 April 2006: 514-515.
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MICROBIOLOGY: Environmentally Sensitive Protein Proves Key to Making Yeast Pathogenic
Elizabeth Pennisi
Science 28 April 2006: 515.
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ScienceScope
Science 28 April 2006: 511.
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Random Samples
Science 28 April 2006: 507.
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Newsmakers
Science 28 April 2006: 525.
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News Focus
CELL BIOLOGY: Picking Up the Pieces After Hwang
Gretchen Vogel
Science 28 April 2006: 516-517.
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BIOMEDICAL RESEARCH: Fragile X's Unwelcome Relative
Greg Miller
Science 28 April 2006: 518-521.
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BIOMEDICAL RESEARCH: A Fix for Fragile X Syndrome?
Greg Miller
Science 28 April 2006: 521.
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ALICE DAUTRY PROFILE: After the Storm, New Pasteur Chief Treads Softly
Martin Enserink
Science 28 April 2006: 522-523.
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AGRICULTURE: New Disease Endangers Florida's Already-Suffering Citrus Trees
Erik Stokstad
Science 28 April 2006: 523-524.
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Letters
This Week's Letters
Science 28 April 2006: 526.
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Ongoing Threats to Endemic Species
J. Michael Scott and Dale D. Goble
Science 28 April 2006: 526.
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A Scientific Supercourse
Ronald E. Laporte, Gilbert S. Omenn, Ismail Serageldin, Vinton G. Cerf, and Faina Linkov
Science 28 April 2006: 526.
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Marine Parks Need Sharks?
Demian D. F. Chapman, Ellen K. Pikitch, Elizabeth A. Babcock;, Peter J. Mumby, Fiorenza Micheli, Craig P. Dahlgren, Steven Y. Litvin, Andrew B. Gill, Daniel R. Brumbaugh, Kenneth Broad, James N. Sanchirico, Carrie V. Kappel, Alastair R. Harborne, and Katherine E. Holmes
Science 28 April 2006: 526-528.
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A Not-So-Abrupt Departure
Michael E. Mann and Malcolm K. Hughes
Science 28 April 2006: 528-529.
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Mechanisms for Resistance in Soil
Stuart B. Levy;, Roger W. Pickup, and Glenn Rhodes
Science 28 April 2006: 529.
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Books et al.
EVOLUTIONARY GENETICS: Broken Cogs or Strategic Agents?
Peter Hammerstein and Edward H. Hagen
Science 28 April 2006: 530.
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ECONOMICS: Nothing Succeeds Like Failure
Sam Kean
Science 28 April 2006: 531.
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Books Received
Science 28 April 2006: 531.
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Education Forum
COMPUTER SIMULATIONS: Technological Advances in Inquiry Learning
Ton de Jong
Science 28 April 2006: 532-533.
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Perspectives
BIOPHYSICS: Lonely Voltage Sensor Seeks Protons for Permeation
Christopher Miller
Science 28 April 2006: 534-535.
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PLANETARY SCIENCE: Ice Among the Rocks
Alan Fitzsimmons
Science 28 April 2006: 535-536.
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ATMOSPHERE: Plant Respiration in a Warmer World
Anthony W. King, Carla A. Gunderson, Wilfred M. Post, David J. Weston, and Stan D. Wullschleger
Science 28 April 2006: 536-537.
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EVOLUTION: Enhanced: Size Does Not Matter for Mitochondrial DNA
Adam Eyre-Walker
Science 28 April 2006: 537-538.
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ASTRONOMY: Pulsar Magnetospheres and Pulsar Death
E. P. J. van den Heuvel
Science 28 April 2006: 539-540.
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NEUROSCIENCE: A Neuronal Receptor for Botulinum Toxin
Reinhard Jahn
Science 28 April 2006: 540-541.
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Association Affairs
AAAS News and Notes
Science 28 April 2006: 542.
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Review
Reefs of the Deep: The Biology and Geology of Cold-Water Coral Ecosystems
J. Murray Roberts, Andrew J. Wheeler, and André Freiwald
Science 28 April 2006: 543-547.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Brevia
Santorini Eruption Radiocarbon Dated to 1627-1600 B.C.
Walter L. Friedrich, Bernd Kromer, Michael Friedrich, Jan Heinemeier, Tom Pfeiffer, and Sahra Talamo
Science 28 April 2006: 548.
A buried olive tree provides a firm early date for the massive Santorini eruption, facilitating correlations among Bronze Age events throughout the Mediterranean.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Reports
A Periodically Active Pulsar Giving Insight into Magnetospheric Physics
M. Kramer, A. G. Lyne, J. T. O'Brien, C. A. Jordan, and D. R. Lorimer
Science 28 April 2006: 549-551.
Published online 23 February 2006 [DOI: 10.1126/science.1124060] (in Science Express Reports)
An intermittent pulsar switches off entirely for several weeks every 30 to 40 days and slows more rapidly while on, implying that pulsar winds periodically slow its spinning.
Abstract »| Full Text »| PDF »|
Quantum-Dot Spin-State Preparation with Near-Unity Fidelity
Mete Atatüre, Jan Dreiser, Antonio Badolato, Alexander Högele, Khaled Karrai, and Atac Imamoglu
Science 28 April 2006: 551-553.
Published online 6 April 2006 [DOI: 10.1126/science.1126074] (in Science Express Reports)
Optical cooling of an electron in a quantum dot to a few millikelvin maintains the spin state with high fidelity, as needed for quantum information storage.
Abstract »| Full Text »| PDF »|
Optical Spectroscopy of Individual Single-Walled Carbon Nanotubes of Defined Chiral Structure
Matthew Y. Sfeir, Tobias Beetz, Feng Wang, Limin Huang, X. M. Henry Huang, Mingyuan Huang, J. Hone, Stephen O'Brien, J. A. Misewich, Tony F. Heinz, Lijun Wu, Yimei Zhu, and Louis E. Brus
Science 28 April 2006: 554-556.
Electronic spectra and diffraction patterns collected simultaneously from single-walled carbon nanotubes reveal details of optical transitions not evident from bulk measurements.
Abstract »| Full Text »| PDF »|
Biologically Inspired Artificial Compound Eyes
Ki-Hun Jeong, Jaeyoun Kim, and Luke P. Lee
Science 28 April 2006: 557-561.
Small polymer refractive lenses connected to conical waveguides arranged about a polymer dome produce an artificial compound eye like that in many insects.
Abstract »| Full Text »| PDF »|
A Population of Comets in the Main Asteroid Belt
Henry H. Hsieh and David Jewitt
Science 28 April 2006: 561-563.
Published online 23 March 2006 [DOI: 10.1126/science.1125150] (in Science Express Reports)
A currently small population of comets exists in the main asteroid belt, differing in origin and temperature from those in the outer solar system.
Abstract »| Full Text »| PDF »|
Iron-Rich Post-Perovskite and the Origin of Ultralow-Velocity Zones
Wendy L. Mao, Ho-kwang Mao, Wolfgang Sturhahn, Jiyong Zhao, Vitali B. Prakapenka, Yue Meng, Jinfu Shu, Yingwei Fei, and Russell J. Hemley
Science 28 April 2006: 564-565.
An iron-rich magnesium silicate mineral, rather than just melt as has been assumed, can account for low seismic velocities at the base of Earth抯 mantle .
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Chronology for the Aegean Late Bronze Age 1700-1400 B.C.
Sturt W. Manning, Christopher Bronk Ramsey, Walter Kutschera, Thomas Higham, Bernd Kromer, Peter Steier, and Eva M. Wild
Science 28 April 2006: 565-569.
Radiocarbon ages from the Aegean region, along with the new age for the Santorini eruption, revise the inferred relations among Minoan, Egyptian, and Near Eastern cultures.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Population Size Does Not Influence Mitochondrial Genetic Diversity in Animals
Eric Bazin, Sylvain Glémin, and Nicolas Galtier
Science 28 April 2006: 570-572.
Mitochondrial DNA, often used as an index of population size because of its assumed evolutionary neutrality, in fact is unpredictably related to population demographics.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Proapoptotic BAX and BAK Modulate the Unfolded Protein Response by a Direct Interaction with IRE1
Claudio Hetz, Paula Bernasconi, Jill Fisher, Ann-Hwee Lee, Michael C. Bassik, Bruno Antonsson, Gabriel S. Brandt, Neal N. Iwakoshi, Anna Schinzel, Laurie H. Glimcher, and Stanley J. Korsmeyer
Science 28 April 2006: 572-576.
Two proteins that act at mitochondria to trigger cell death when cells are damaged also promote survival responses at the endoplasmic reticulum when cells are under stress.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Natural Malaria Infection in Anopheles gambiae Is Regulated by a Single Genomic Control Region
Michelle M. Riehle, Kyriacos Markianos, Oumou Niaré, Jiannong Xu, Jun Li, Abdoulaye M. Touré, Belco Podiougou, Frederick Oduol, Sory Diawara, Mouctar Diallo, Boubacar Coulibaly, Ahmed Ouatara, Leonid Kruglyak, Sékou F. Traoré, and Kenneth D. Vernick
Science 28 April 2006: 577-579.
A cluster of mosquito genes similar to innate immunity genes from other species confers resistance to the malaria parasite in a large proportion of wild mosquitoes.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Autophagic Fungal Cell Death Is Necessary for Infection by the Rice Blast Fungus
Claire Veneault-Fourrey, Madhumita Barooah, Martin Egan, Gavin Wakley, and Nicholas J. Talbot
Science 28 April 2006: 580-583.
For successful infection, a serious fungal pathogen of rice builds specialized cellular structures that pierce the plant cuticle, a process that requires autophagic cell death.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Global Control of Dimorphism and Virulence in Fungi
Julie C. Nemecek, Marcel Wüthrich, and Bruce S. Klein
Science 28 April 2006: 583-588.
When fungal spores are inhaled, a regulatory receptor senses the host environment and shifts their morphology from a filamentous to a virulent yeast form.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
A Voltage Sensor-Domain Protein Is a Voltage-Gated Proton Channel
Mari Sasaki, Masahiro Takagi, and Yasushi Okamura
Science 28 April 2006: 589-592.
Published online 23 March 2006 [DOI: 10.1126/science.1122352] (in Science Express Reports)
Most of a voltage-gated protein proton channel consists of a four-transmembrane domain similar to the voltage sensor of other channels.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
SV2 Is the Protein Receptor for Botulinum Neurotoxin A
Min Dong, Felix Yeh, William H. Tepp, Camin Dean, Eric A. Johnson, Roger Janz, and Edwin R. Chapman
Science 28 April 2006: 592-596.
Published online 16 March 2006 [DOI: 10.1126/science.1123654] (in Science Express Reports)
One of the toxins from botulinum enters neurons by hitching a ride on proteins that are exposed when synaptic vesicles release neurotransmitters and are then recycled.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Retinoid Signaling Determines Germ Cell Fate in Mice
Josephine Bowles, Deon Knight, Christopher Smith, Dagmar Wilhelm, Joy Richman, Satoru Mamiya, Kenta Yashiro, Kallayanee Chawengsaksophak, Megan J. Wilson, Janet Rossant, Hiroshi Hamada, and Peter Koopman
Science 28 April 2006: 596-600.
Published online 30 March 2006 [DOI: 10.1126/science.1125691] (in Science Express Reports)
The hormone retinoid triggers meiosis in the germ cells of the mouse ovary, stimulating oocyte formation; retinoid is degraded in the testis, allowing the generation of sperm.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Technical Comments
Comment on "Reconstructing Past Climate from Noisy Data"
Eugene R. Wahl, David M. Ritson, and Caspar M. Ammann
Science 28 April 2006: 529.
Abstract »| Full Text »| PDF »|
Response to Comment on "Reconstructing Past Climate from Noisy Data"
Hans von Storch, Eduardo Zorita, Julie M. Jones, Fidel Gonzalez-Rouco, and Simon F. B. Tett
Science 28 April 2006: 529.
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