| 2006年08月10日 Nature中英文摘要 | | 点击： 作者： 来源： 时间： 2006-11-12 本站论坛 |
|  | 
Volume 442 Number 7103 pp601-718 (10 August 2006)
封面故事：5亿年前的动物胚胎化石？
保存非常好的、距今已有5亿年的动物胚胎化石（里面嵌入了磷酸钙，外面也包裹了一层磷酸钙）引起人们很大兴趣，因为它们可能含有关于动物演化一个关键阶段的发育过程的宝贵信息。 这些化石尺寸很小，这使得人们难以对它们进行研究，但一种新开发的方法可以让科学家恢复以前无法接触到的结构细节。这种新方法要用到利用一个同步加速器X-射线光源进行亚微米尺度的断层分析，它被用来解决化石形成过程中的一些极端问题。关于已知最早的两侧对称动物胚胎Markuelia 和 Pseudooides的微型化石的内部解剖结构的引人注目的数据，澄清了关于前者发展史的某些疑问，并且显示了关于后者发育过程的一个以前未知的模型。本期封面所示为一个Markuelia胚胎的一系列虚拟切片，它们既显示了这种动物的胚胎特征，也显示了其死后特征。
可提高水稻抗涝性能的基因
在很多亚洲国家，由于洪水损毁水稻作物而导致巨大的经济损失。大多数水稻栽培品种会在完全浸在水中后一周内死亡，但也有一些品种能在水下生存几个星期时间，这是由于它们有一个较大的定量特性基因位点，被称为Submergence 1 (Sub1)，其位置在第9号染色体的着丝点附近。现在，对 Sub1基因所做的一项详细研究发现，其中的一个基因Sub1A是水稻抗浸没性能的主要决定因子。将Sub1A引入一种在亚洲广泛栽培的水稻品种中，可提高其在洪水条件下的存活率，而不需要以牺牲其高产量和其他优点为代价。
关于古老恒星中锂数量的矛盾被解决
对宇宙微波背景所做的精确测量，揭示了关于早期宇宙的性质及其膨胀过程的很多信息。然而，有一个长期未能解决的矛盾：在最古老恒星上所观测到的锂的量不到“大爆炸”中的核反应所产生的锂的一半。现在，Korn等人解决了这一矛盾。他们发现，其他元素的丰度变化趋势可由扩散性涡动混合过程来解释，这个过程将锂带到了恒星深层。
直径小于100米的海王星外天体
Scorpius X-1 (Sco X1)在天文学历史中具有重要地位，因为它曾经是除太阳以外第一个所探测到的宇宙X-射线源。现在，它有了一个新头衔：由“Rossi X-射线定时探测器”卫星所获得的关于该天体X-射线光曲线中小而显著的下降，可能代表着首次观测到的小型（直径小于100米）海王星外天体（TNO）。这些不规则性出现在毫秒尺度上，几乎可以肯定是由微型TNO的隐藏造成的。自从奎波带天体首次于1992年被发现以来， 迄今已经发现了超过1000个TNO。已经观测到的TNO 直径在数百公里至几千公里之间，但预计还存在很多更小的天体。
声子-偏振子波及相关X-射线衍射技术
通过空气传播的光的基本粒子是光子。但当光通过凝聚态物质传播时，它会与凝聚态物质的晶格产生耦合，生成复杂的粒子，被称为偏振子。一项新的研究工作，利用超快X-射线衍射来直接观测支持固体中这种光激发的原子位移。在这项研究中，穿过铁电性钽酸锂（LiTaO3）传播的太赫辐射与晶格振动产生耦合，生成声子-偏振子波。这种新的X-射线衍射技术使研究人员有可能去跟踪晶格中支持这种波的传播的离子的绝对位移。
火山岩浆从地幔流出的机制
沿地球构造边界分布的火山的岩浆，是来自深层地幔中所产生的熔融物，但这些熔融物是怎样从地幔到达火山的却仍然不清楚。受到最近一些发现部分熔融的岩石中存在由应力驱动的分离现象的实验工作的启发，Katz等人提出了一个新理论，来解释这一系统的行为。该理论预测，在正在发生变形的、部分熔融的团块中，会自然出现成带状分布的集中的熔融物和剪切力。这说明，熔融的岩石从海洋中部山脊下面的地幔中的快速流出，可能是通过一个具有高度渗透性的、由富含熔融物的带状结构结成的网络发生的，而不是通过慢速流动的、统一分布的多孔流发生的。
小鼠鼻子中的第二套嗅觉受体
研究人员在小鼠鼻子中发现了第二套嗅觉受体，其中包括一些可能探测信息素、因而也许与交配有关的嗅觉受体。这些受体的基因也存在于鱼类和人类中，这让我们看到这样一个可能性：一种人类信息素受体可能很快将被发现。新发现的与痕量胺相关的受体（TAAR）存在于鼻腔内层中一组独特的细胞表面上，与探测气味的受体分子明显不同。 至少有三种不同的TAAR识别小鼠尿液中的不同化合物，这说明它们在探测个体间微妙的化学信息中可能扮演一个角色。
“刺胞动物”与两侧对称动物的Hox基因
从昆虫到人类的两侧对称动物的身体主轴，是在名为Hox的同一组基因的指示下形成的。了解Hox基因的演化及相关的ParaHox基因，需要关于在更为古老的动物类别中的Hox基因的互补基因的知识。Chourrout等人研究了这样两种动物中的Hox基因，它们分别是“刺胞动物”Nematstella 和 Hydra， 是在距今6亿年前出现的。虽然这些生物具有与两侧对称动物的前部Hox基因群相应的基因，但这些Hox基因的其余部分却有独立起源的迹象。该研究还表明，假设中的ProtoHox祖先基因群有一个简单的起源，即起源于仅仅两个基因。经过广泛的基因复制后，“刺胞动物”和两侧对称动物的Hox基因群遵从了独立的演化轨迹，得到了不同的结局。
Card9蛋白与先天免疫性的关系
我们很不了解的Card9蛋白（在结构上与先天免疫系统中所涉及的Carma蛋白相关）存在于包括血液淋巴细胞和脾脏在内的各种不同组织中。现在，Card9被发现控制一种以前不知道的、具有抗菌活性的先天免疫通道。Card9与Dectin-1发生相互作用，后者是哺乳动物先天免疫系统探测真菌的主要模式识别受体。该结果表明，先天和适应性免疫系统在演化上截然不同的ITAM受体，都通过对上游适应子的不同使用来选择性地结合保留下来的Bcl10/Malt1信号作用模块。
IT皮质中的神经活动与物体识别相关
在灵长类动物大脑皮层中一个被称为下颞叶皮质(IT)的区域所进行的直接电生理记录和fMRI扫描实验表明，该区域选择性地对高度复杂的视觉刺激（如面部特征）做出响应，从而导致这样一个假设：大脑中这个区域与物体识别有关。现在，研究人员获得了该假设的直接证据，因为他们发现了面部选择神经元与面部识别之间的一个直接联系。 IT皮质中面部选择神经元的微弱电刺激，会导致猴子关于面部类别的决定发生一个严重偏差。除了将 IT皮质中的神经活动与物体识别联系起来外，这项研究工作还为今后进行关于物体形状的神经编码的研究搭建了舞台。
Contents
Editorials
Safeguards for donors p601
Clashing perspectives on the ethics of the donation of human eggs for research purposes are likely to complicate international collaboration — whether stem-cell researchers like it or not.
doi:10.1038/442601a
Full Text | PDF (120K)
--------------------------------------------------------------------------------
Capturing carbon p601
Sequestration of greenhouse gases could play an important role in capping emissions.
doi:10.1038/442601b
Full Text | PDF (131K)
--------------------------------------------------------------------------------
Toronto crossroads p602
The international AIDS meeting still has a purpose.
doi:10.1038/442602a
Full Text | PDF (100K)
--------------------------------------------------------------------------------
Top of pageResearch Highlights
Research highlights p604
doi:10.1038/442604a
Full Text | PDF (294K)
--------------------------------------------------------------------------------
Top of pageNews
Ethicists and biologists ponder the price of eggs p606
A Nature Special Report investigates the ethics and economics of donating eggs for stem-cell research. In this, the first part Erika Check investigates whether paying donors would increase supply. In the second part Helen Pearson asks what is known about the long-term health risks faced by donors.
Erika Check
doi:10.1038/442606a
Full Text | PDF (276K)
--------------------------------------------------------------------------------
Health effects of egg donation may take decades to emerge p607
A Nature Special Report investigates the ethics and economics of donating eggs for stem-cell research. In the first part Erika Check investigated whether paying donors would increase supply. In this, the second part Helen Pearson asks what is known about the long-term health risks faced by donors.
Helen Pearson
doi:10.1038/442607a
Full Text | PDF (369K)
--------------------------------------------------------------------------------
Oil from bombed plant left to spill p609
War hampers clean-up efforts.
Kerri Smith with additional reporting by Michael Hopkin
doi:10.1038/442609a
Full Text | PDF (218K)
--------------------------------------------------------------------------------
Plan for postdoc union sparks backlash p609
University of California awaits petition ruling.
Heidi Ledford
doi:10.1038/442609b
Full Text | PDF (218K)
--------------------------------------------------------------------------------
AIDS vaccine research becomes 'big science' p610
But 'mission-oriented' approach has its critics.
Declan Butler
doi:10.1038/442610a
Full Text | PDF (295K)
See also: Editor's summary
--------------------------------------------------------------------------------
Sidelines p611
doi:10.1038/442611a
Full Text | PDF (174K)
--------------------------------------------------------------------------------
Views collide over fate of accelerator p612
Decommissioned particle smasher awaits fate.
Geoff Brumfiel
doi:10.1038/442612a
Full Text | PDF (179K)
--------------------------------------------------------------------------------
News in brief p613
doi:10.1038/442613a
Full Text | PDF (158K)
--------------------------------------------------------------------------------
Correction p613
doi:10.1038/442613b
Full Text | PDF (158K)
--------------------------------------------------------------------------------
Top of pageBusiness
Silent running: the race to the clinic p614
A technique for turning genes off has sparked a flurry of biotech investment. Erika Check investigates.
doi:10.1038/442614a
Full Text | PDF (275K)
--------------------------------------------------------------------------------
In brief p615
doi:10.1038/442615a
Full Text | PDF (114K)
--------------------------------------------------------------------------------
Market watch p615
Quirin Schiermeier
doi:10.1038/442615b
Full Text | PDF (114K)
--------------------------------------------------------------------------------
Top of pageNews Features
AIDS treatment: Staying the course p617
Some feared that widespread use of AIDS treatments in Africa would encourage drug resistance, with globally disastrous consequences. But there's no crisis yet, reports Erika Check.
doi:10.1038/442617a
Full Text | PDF (686K)
See also: Editor's summary
--------------------------------------------------------------------------------
Putting the carbon back: The hundred billion tonne challenge p620
One way to keep carbon dioxide out of the atmosphere is to put it back in the ground. In this, the first of two News Features on carbon sequestration, Quirin Schiermeier asks when the world's coal-fired power plants will start storing away their carbon. In the second, Emma Marris joins the enthusiasts who think that enriching Earth's soils with charcoal can help avert global warming, reduce the need for fertilizers, and greatly increase the size of turnips.
doi:10.1038/442620a
Full Text | PDF (1,279K)
See also: Editor's summary
--------------------------------------------------------------------------------
Putting the carbon back: Black is the new green p624
One way to keep carbon dioxide out of the atmosphere is to put it back in the ground. In the first of two News Features on carbon sequestration, Quirin Schiermeier asked when the world's coal-fired power plants will start storing away their carbon. In the second, Emma Marris joins the enthusiasts who think that enriching Earth's soils with charcoal can help avert global warming, reduce the need for fertilizers, and greatly increase the size of turnips.
doi:10.1038/442624a
Full Text | PDF (1,613K)
See also: Editor's summary
--------------------------------------------------------------------------------
Top of pageCorrespondence
Scientists are well placed to speak up for biodiversity p627
Guillaume Chapron
doi:10.1038/442627a
Full Text | PDF (107K)
--------------------------------------------------------------------------------
Authors were clear about hockey-stick uncertainties p627
Raymond S. Bradley, Malcolm K. Hughes and Michael E. Mann
doi:10.1038/442627b
Full Text | PDF (107K)
--------------------------------------------------------------------------------
Systems biology could help us harness useful microbes p627
Douglas Young
doi:10.1038/442627c
Full Text | PDF (107K)
--------------------------------------------------------------------------------
Sticking points in the push for change p627
Eugene A. Rosa
doi:10.1038/442627d
Full Text | PDF (107K)
--------------------------------------------------------------------------------
Top of pageCommentary
Fair payment or undue inducement? p629
Women who donate their eggs for stem-cell research should be compensated in the same way as other healthy research volunteers, argues Insoo Hyun.
doi:10.1038/442629a
Full Text | PDF (302K)
See also: Editor's summary
--------------------------------------------------------------------------------
Top of pageBooks and Arts
The Moses of Silicon Valley p631
William Shockley's work led to the foundation of the US computer industry.
Paul Grant reviews Broken Genius: The Rise and Fall of William Shockley, Creator of the Electronic Age by Joel N. Shurkin
doi:10.1038/442631a
Full Text | PDF (275K)
--------------------------------------------------------------------------------
New in paperback p632
doi:10.1038/442632a
Full Text | PDF (275K)
--------------------------------------------------------------------------------
Making sense of autism p632
Francesca Happé reviews Autism, Brain, and Environment by Richard Lathe and Understanding Autism: From Basic Neuroscience to Treatment edited by Steven O. Moldin and John L. R. Rubenstein
doi:10.1038/442632b
Full Text | PDF (275K)
--------------------------------------------------------------------------------
Subterranean storage blues p633
Gordon MacKerron reviews Uncertainty Underground: Yucca Mountain and the Nation's High-Level Nuclear Waste edited by Allison M. Macfarlane and Rodney C. Ewing
doi:10.1038/442633a
Full Text | PDF (275K)
See also: Editor's summary
--------------------------------------------------------------------------------
Top of pageNews and Views
Plant breeding: Rice in deep water p635
Many otherwise productive cultivars of rice suffer badly if immersed in water for long. The identification of a gene variant that confers tolerance to this threat has practical potential.
Takuji Sasaki
doi:10.1038/442635a
Full Text | PDF (634K)
See also: Editor's summary
--------------------------------------------------------------------------------
Cosmology: Where all the lithium went p636
For some years, astronomers have been trying to track down all the lithium predicted by standard cosmological models. Spectroscopic dissection of globular clusters reveals that the answer might lie in the stars.
Corinne Charbonnel
doi:10.1038/442636a
Full Text | PDF (385K)
See also: Editor's summary
--------------------------------------------------------------------------------
Neuroscience: An extra dimension to olfaction p637
The sense of smell is triggered by receptors in the olfactory epithelium that lines the nose. In mice at least, that lining is also responsible for receiving chemosensory cues involved in mating and other social behaviours.
John Ngai
doi:10.1038/nature05001
Full Text | PDF (225K)
See also: Editor's summary
--------------------------------------------------------------------------------
Materials science: Organosilica the conciliator p638
Acidic and basic molecules are antagonistic, and keeping them in their place is no easy job — unless, it seems, one unites them under the tutelage of ordered, nanoporous materials known as organosilicas.
Mietek Jaroniec
doi:10.1038/442638a
Full Text | PDF (541K)
--------------------------------------------------------------------------------
Solar System: Sifting through the debris p640
A quadrillion previously unnoticed small bodies beyond Neptune have been spotted as they dimmed X-rays from a distant source. Models of the dynamics of debris in the Solar System's suburbs must now be reworked.
Asantha Cooray
doi:10.1038/442640a
Full Text | PDF (400K)
See also: Editor's summary
--------------------------------------------------------------------------------
Neurodegenerative disease: Cut to the chase p641
A family of enzymes called caspases — best known for their involvement in programmed cell death — now seems to be pivotal in the progression of two neurodegenerative diseases.
Lisa M. Ellerby and Harry T. Orr
doi:10.1038/442641a
Full Text | PDF (149K)
--------------------------------------------------------------------------------
50 & 100 years ago p642
doi:10.1038/442642a
Full Text | PDF (132K)
--------------------------------------------------------------------------------
Microscopy: Nanotomography comes of age p642
The use of X-rays to construct three-dimensional tomographic images is well established in medicine. The same principle is being extended to the nanoscale, bringing us startlingly accurate pictures of tiny objects.
David Attwood
doi:10.1038/442642b
Full Text | PDF (279K)
--------------------------------------------------------------------------------
Neuroscience: Making faces in the brain p644
Artificially activating the right neurons at the right time causes visual perception of a face. This new result shows that such neurons directly underlie the recognition of complex objects.
James J. DiCarlo
doi:10.1038/nature05000
Full Text | PDF (122K)
See also: Editor's summary
--------------------------------------------------------------------------------
Top of pageArticles
A second class of chemosensory receptors in the olfactory epithelium p645
Stephen D. Liberles and Linda B. Buck
doi:10.1038/nature05066
Abstract | Full Text | PDF (970K) | Supplementary information
See also: Editor's summary | News and Views by Ngai
--------------------------------------------------------------------------------
Card9 controls a non-TLR signalling pathway for innate anti-fungal immunity p651
Olaf Gross, Andreas Gewies, Katrin Finger, Martin Schäfer, Tim Sparwasser, Christian Peschel, Irmgard Förster and Jürgen Ruland
doi:10.1038/nature04926
Abstract | Full Text | PDF (581K) | Supplementary information
See also: Editor's summary
--------------------------------------------------------------------------------
Top of pageLetters
A probable stellar solution to the cosmological lithium discrepancy p657
A. J. Korn, F. Grundahl, O. Richard, P. S. Barklem, L. Mashonkina, R. Collet, N. Piskunov and B. Gustafsson
doi:10.1038/nature05011
First paragraph | Full Text | PDF (142K) | Supplementary information
See also: Editor's summary
--------------------------------------------------------------------------------
Occultation of X-rays from Scorpius X-1 by small trans-neptunian objects p660
Hsiang-Kuang Chang, Sun-Kun King, Jau-Shian Liang, Ping-Shien Wu, Lupin Chun-Che Lin and Jeng-Lun Chiu
doi:10.1038/nature04941
First paragraph | Full Text | PDF (239K) | Supplementary information
See also: Editor's summary
--------------------------------------------------------------------------------
Tracking the motion of charges in a terahertz light field by femtosecond X-ray diffraction p664
A. Cavalleri, S. Wall, C. Simpson, E. Statz, D. W. Ward, K. A. Nelson, M. Rini and R. W. Schoenlein
doi:10.1038/nature05041
First paragraph | Full Text | PDF (275K)
See also: Editor's summary
--------------------------------------------------------------------------------
Supercurrent reversal in quantum dots p667
Jorden A. van Dam, Yuli V. Nazarov, Erik P. A. M. Bakkers, Silvano De Franceschi and Leo P. Kouwenhoven
doi:10.1038/nature05018
First paragraph | Full Text | PDF (423K) | Supplementary information
--------------------------------------------------------------------------------
Arctic hydrology during global warming at the Palaeocene/Eocene thermal maximum p671
Mark Pagani, Nikolai Pedentchouk, Matthew Huber, Appy Sluijs, Stefan Schouten, Henk Brinkhuis, Jaap S. Sinninghe Damsté, Gerald R. Dickens and Expedition 302 Scientists and Expedition 302 Scientists
doi:10.1038/nature05043
First paragraph | Full Text | PDF (247K) | Supplementary information
--------------------------------------------------------------------------------
The dynamics of melt and shear localization in partially molten aggregates p676
Richard F. Katz, Marc Spiegelman and Benjamin Holtzman
doi:10.1038/nature05039
First paragraph | Full Text | PDF (538K) | Supplementary information
See also: Editor's summary
--------------------------------------------------------------------------------
Synchrotron X-ray tomographic microscopy of fossil embryos p680
Philip C. J. Donoghue, Stefan Bengtson, Xi-ping Dong, Neil J. Gostling, Therese Huldtgren, John A. Cunningham, Chongyu Yin, Zhao Yue, Fan Peng and Marco Stampanoni
doi:10.1038/nature04890
First paragraph | Full Text | PDF (454K) | Supplementary information
See also: Editor's summary
--------------------------------------------------------------------------------
Minimal ProtoHox cluster inferred from bilaterian and cnidarian Hox complements p684
D. Chourrout, F. Delsuc, P. Chourrout, R. B. Edvardsen, F. Rentzsch, E. Renfer, M. F. Jensen, B. Zhu, P. de Jong, R. E. Steele and U. Technau
doi:10.1038/nature04863
First paragraph | Full Text | PDF (337K) | Supplementary information
See also: Editor's summary
--------------------------------------------------------------------------------
Mesodermal Wnt2b signalling positively regulates liver specification p688
Elke A. Ober, Heather Verkade, Holly A. Field and Didier Y. R. Stainier
doi:10.1038/nature04888
First paragraph | Full Text | PDF (532K) | Supplementary information
--------------------------------------------------------------------------------
Microstimulation of inferotemporal cortex influences face categorization p692
Seyed-Reza Afraz, Roozbeh Kiani and Hossein Esteky
doi:10.1038/nature04982
First paragraph | Full Text | PDF (400K) | Supplementary information
See also: Editor's summary | News and Views by DiCarlo
--------------------------------------------------------------------------------
Enzymatic activation of voltage-gated potassium channels p696
Yajamana Ramu, Yanping Xu and Zhe Lu
doi:10.1038/nature04880
First paragraph | Full Text | PDF (808K) | Supplementary information
--------------------------------------------------------------------------------
An ARC/Mediator subunit required for SREBP control of cholesterol and lipid homeostasis p700
Fajun Yang, Bryan W. Vought, John S. Satterlee, Amy K. Walker, Z.-Y. Jim Sun, Jennifer L. Watts, Rosalie DeBeaumont, R. Mako Saito, Sven G. Hyberts, Shaosong Yang, Christine Macol, Lakshmanan Iyer, Robert Tjian, Sander van den Heuvel, Anne C. Hart, Gerhard Wagner and Anders M. Näär
doi:10.1038/nature04942
First paragraph | Full Text | PDF (795K) | Supplementary information
--------------------------------------------------------------------------------
Sub1A is an ethylene-response-factor-like gene that confers submergence tolerance to rice p705
Kenong Xu, Xia Xu, Takeshi Fukao, Patrick Canlas, Reycel Maghirang-Rodriguez, Sigrid Heuer, Abdelbagi M. Ismail, Julia Bailey-Serres, Pamela C. Ronald and David J. Mackill
doi:10.1038/nature04920
First paragraph | Full Text | PDF (418K) | Supplementary information
See also: Editor's summary
--------------------------------------------------------------------------------
Assembly dynamics of microtubules at molecular resolution p709
Jacob W. J. Kerssemakers, E. Laura Munteanu, Liedewij Laan, Tim L. Noetzel, Marcel E. Janson and Marileen Dogterom
doi:10.1038/nature04928
First paragraph | Full Text | PDF (1,629K) | Supplementary information
--------------------------------------------------------------------------------
Top of pageNaturejobs
Prospect
Prospects p713
Postdoc is caught up in Israeli-Hezbollah conflict.
Paul Smaglik
doi:10.1038/nj7102-713a
Full Text | PDF (166K)
--------------------------------------------------------------------------------
Region
Japan's other research hub p714
The city of Sendai has much to offer research and industry, but, says David Cyranoski, competition for funding and brains is stiff.
David Cyranoski
doi:10.1038/nj7103-714a
Full Text | PDF (1,446K)
--------------------------------------------------------------------------------
Top of pageFutures
Statler pulchrifex p718
Make love and war.
Matt Weber
doi:10.1038/442718a
Full Text | PDF (118K)
|
上一篇：2006年08月17日 Nature中英文摘要 下一篇：2006年08月03日 Nature中英文摘要
| |
|
|
|
