| 2005年05月12日 Nature中文摘要 | | 点击： 作者： 来源： 时间： 2006-11-11 本站论坛 |
|  | Volume 435 Number 7039 pp129-246
封面故事：巨型水母的眼睛
巨型水母（Cubozoans）每个有24只四种类型的眼睛，但却没有用于信息处理的中央大脑。对这些眼睛所做的一项研究显示，它们的光学系统同脊椎动物的光学系统一样复杂。尽管如此，其视网膜却在焦点之外，清楚的图像不是用来看清东西的，而是作为处理视觉信息的一种方式。“模糊的”视图也许对避开静止的大目标、同时又不必关注小的漂浮目标和浮游生物非常有利。在动物视觉系统的早期演化中有一个缺少的环节，在这个环节中眼睛很可能只执行单一的任务，即看东西。关于巨型水母眼睛研究的新发现也为了解这个缺少的环节提供了一个线索。本期封面所示为本研究中所用的Chiropsalmus sp.的两只透镜眼睛和两对色素坑眼睛，它们比Tripedalia cystophora的眼睛大，但却与其相似。摄影：Dan-E. Nilsson。
能自我复制的机器人
自我复制是活生物的一个特性，但却在很大程度上被工程师和材料学家所忽略，他们对一次性的自组装更感兴趣。但自我复制也有非常有用的时候，在本期Nature上，研究人员通过能够进行物理自我复制的简单机器的研制，向我们展示了非生命世界在这个方向上能走多远。这些简单的机器是模块化的机器人，每个10厘米长的模块都有电磁铁，能够选择性地削弱和增强连接，从而决定体系结构在什么地方断开和接合。一个由三个模块构成的机器人能在仅仅一分钟多的时间内完成复制（关于这种本领的影片，请看补充信息）。与生物体系相比虽然简单，但这些机器人说明，自我复制并不是生物特有的。这种设计概念对于危险环境中的自持系统的设计可能是有用的，如在空间探索中所遇到的环境条件，在这些环境条件下采用传统维护方法是不现实的。
决定身体组织对称性的因素
虽然从外面看是对称的，但脊椎动物和其他动物的身体结构从里面看却远不是对称的。当人类心脏和肺在胚胎中形成的时候，它们是朝向体腔左侧和右侧的。为了确定形成这种不对称性的遗传规律和信号机制，科学家进行了很多研究，但却存在这样一个困难：一些组织，主要是肌肉和骨骼组织，必须忽略或抵制让其对称的指令才能成为不对称的结构。本期Nature上有三篇论文和由Eran Hornstein 和Clifford J. Taboin撰写的一篇News and Views文章，探讨了形成对称组织的胚胎元素“体节”（somites）是怎样实现不对称性的这一有趣的问题。
火星南极冰盖为什么不在其南极？
为什么火星的南极冰盖不在其南极？自从19世纪对火星进行早期观测以来，由冰冻CO2构成的火星南极常年冰盖位置的奇怪偏置以及在相邻半球上一个“神秘的”暗区域的存在一直使天文学家感到迷惑不解。现在，将天文观测和气候模拟结合起来所做的一项研究表明，南极冰盖的偏置和神秘区域的形成是由大气流动与巨型火山Tharsis的最南端部分及大型碰撞坑Argyre和Hellas发生相互作用而形成的两个截然不同的气候体系所产生的结果。
解释生物材料紧张变硬的简单理论
与大多数合成材料不同的是，生物材料经常在紧张时变硬。这一性质是血管、肺软组织和血栓等组织的生理功能的关键，自19世纪以来就有文献记录，但其分子结构和设计原理却不为人们所知。现在，Storm等人发现，一个非常简单的理论可解释细胞骨架蛋白和细胞外蛋白所形成的一系列生物聚合物胶体的紧张变硬现象。按照这一理论，排列成一个开放的交联网络的细丝蛋白等半柔性链体系，在低度紧张时便会不可避免地变硬，而不需要一个特定的架构或具有不同内在硬度特征的多种要素。
火星陨石碰撞坑的磁异常
最近的火星探测工作显示，巨型碰撞坑Argye和Hellas与其周围区域相比磁场强度要低得多。普遍认为，磁场强度的降低是由于在陨石碰撞过程中所产生的震荡波引起的压力去磁作用造成的，这意味着在陨石碰撞时火星没有内部产生的磁场。地球上已知最大和最古老的碰撞坑，即南非的Vredefort碰撞坑，是与火星上这两个大型碰撞坑最相似的地球上的碰撞坑。对Vredefort所做的一项研究显示，同在火星上一样，地球上这一巨型碰撞坑上的磁场强度也要低于平均水平。然而这一碰撞坑中的岩石却比地球上其他地方的类似岩石的磁场强度大得多。古磁数据表明，这些碰撞坑的磁场方向是随机的，说明火星碰撞坑的磁异常可能是因为火星没有磁场。
蜜蜂的舞蹈语言
Karl von Frisch发现，当采蜜的蜜蜂在发现一个新的食物来源后而返回蜂巢时，它们会跳一种摇摆舞，这种舞蹈中含有关于所发现食物来源的距离和方位的编码信息。他因这一发现而获得了诺贝尔奖。他假设，其他加入该舞蹈的蜜蜂会阅读这种编码，并利用这种信息找到那个食物来源。对这种假设持怀疑态度者提出，旁观的蜜蜂只是从跳舞的蜜蜂身上获得食物气味，然后凭借气味搜寻食物来源。尽管大多数生物学家倾向于Karl von Frisch关于舞蹈是真正信息来源的观点，但关于这种“编码”是怎样被翻译成一种“飞行计划”的却一直没有定量描述。现在，Riley等人利用一种能够跟踪加入蜂群的每只蜜蜂飞行路径的雷达跟踪系统，发现蜜蜂不仅能够阅读舞蹈中的编码信息，而且在它们飞向目标的过程中也不会受风向变化的影响。
人类行动时机的选择
什么决定人类的行动时机？这是一个大问题，人类动态学这门学科所研究的就是这个问题，该学科的预测具有实用价值：例如，当互联网服务提供商决定一个机构需要什么带宽时，它们要利用一个关于每个人可能的上网时间和活动水平的模型。目前的模型假设，一个人在一个给定的时刻有一个从事某一特定活动的非常明确的概率，但关于人类活动的时机不遵从这一规律（即Poisson统计规律）的证据正在出现。相反，两次连续事件之间的延迟可用所谓的heavy-tailed（power law）分布得到最好的描述。Albert-László Barabási为这种行为的流行提出了一个解释。他发现，人类动态的“突发”性质是决策行动的一个基本结果。
自免疫疾病的致病机理和可能疗法
自免疫反应（在此过程中身体的白血球伤害自己的组织）引起很多疾病，包括糖尿病、多发性硬化和关节炎。免疫细胞为什么只以某些器官为目标？尤其是在糖尿病中，为什么只有产生胰岛素的细胞被杀死？对此，我们并不了解。现在，Nakayama等人报告，这可能是因为胰岛素本身是自免疫糖尿病的一个主要自体抗原。在NOD小鼠（研究糖尿病的标准动物模型）中，当胰岛素分子上产生自体抗体的部分被改变时，自免疫糖尿病会消失。这也说明，删除式免疫疗法可能是一种实用的疗法。这项工作可能的临床意义被另一项在人类慢性I-型糖尿病患者身上所做的研究工作证实。该研究发现，胰腺周围分泌淋巴液的淋巴节中的T-淋巴细胞专门识别一部分胰岛素蛋白。这一发现对糖尿病的特定抗原疗法和胰岛细胞移植方法的可能应用具有参考意义。
本期目录：
Editorials
Blair's failure p129
Britain's research base is flourishing, and Tony Blair's last two governments can take much of the credit for it. But his third needs to focus on the troubled state of the universities.
doi: 10.1038/435129a
Full Text | PDF (77K)
--------------------------------------------------------------------------------
Proposals, please p129
You have one more month to submit proposals for ESOF2006, a fledgling but important forum for European science.
doi: 10.1038/435129b
Full Text | PDF (78K)
--------------------------------------------------------------------------------
Top of pageNews
'Refusal to share' leaves agency struggling to monitor bird flu p131
The WHO isn't being sent samples of deadly H5N1 virus.
Declan Butler
doi: 10.1038/435131a
Full Text | PDF (250K)
--------------------------------------------------------------------------------
Nations spar over erosion of nuclear treaty p132
Non-proliferation meeting can't even agree agenda.
Geoff Brumfiel
doi: 10.1038/435132a
Full Text | PDF (265K)
--------------------------------------------------------------------------------
Polio fight falters as Yemen and Java report fresh cases p133
Carina Dennis
doi: 10.1038/435133a
Full Text | PDF (578K)
--------------------------------------------------------------------------------
Competition boosts bid to find human genes p134
Teams race to develop better predictive software.
Alison Abbott
doi: 10.1038/435134a
Full Text | PDF (238K)
--------------------------------------------------------------------------------
Early martian visitors are caught on camera p134
Tony Reichhardt
doi: 10.1038/435134b
Full Text | PDF (238K)
--------------------------------------------------------------------------------
Cleaner skies leave global warming forecasts uncertain p135
Will reduced air pollution hasten climate change?
Quirin Schiermeier
doi: 10.1038/435135a
Full Text | PDF (163K)
--------------------------------------------------------------------------------
Wanted: scientists to shape Europe's future research policy p135
New agency's governing council will soon be named.
Alison Abbott
doi: 10.1038/435135b
Full Text | PDF (165K)
--------------------------------------------------------------------------------
news in brief p136
doi: 10.1038/435136a
Full Text | PDF (525K)
--------------------------------------------------------------------------------
Editorial note p137
doi: 10.1038/435137a
Full Text | PDF (241K)
--------------------------------------------------------------------------------
Top of pageNews Features
Chinese clinical trials: Consenting adults? Not necessarily... p138
Companies and scientists in the West are keen to test their drugs in China, which is an important future market. But those running clinical trials need to be on their guard, says David Cyranoski.
doi: 10.1038/435138a
Full Text | PDF (495K)
See also: Editor's summary
--------------------------------------------------------------------------------
Spanish astronomy: Rising star p140
As construction on the world's largest optical telescope nears completion in Spain, the country's astronomers are gearing up for an expanded role on the global stage. Mark Peplow follows the preparations for first light.
doi: 10.1038/435140a
Full Text | PDF (1,008K)
--------------------------------------------------------------------------------
Top of pageCorrespondence
Universities should foster neglected-disease work p143
Shifting the focus from patents and revenue to human welfare would speed progress.
Dave A. Chokshi
doi: 10.1038/435143a
Full Text | PDF (76K)
--------------------------------------------------------------------------------
Two-stage drug approval would reduce the risks p143
John A. Frantz
doi: 10.1038/435143b
Full Text | PDF (78K)
--------------------------------------------------------------------------------
Seeing clearly is not necessarily believing p143
Mott T. Greene
doi: 10.1038/435143c
Full Text | PDF (78K)
--------------------------------------------------------------------------------
Top of pageBooks and Arts
Death on the farm p145
Is the control of foot-and-mouth worse than the disease?
Matthew Baylis reviews A Manufactured Plague: The History of Foot-and-Mouth Disease in Britain by Abigail Woods
doi: 10.1038/435145a
Full Text | PDF (457K)
--------------------------------------------------------------------------------
Hitting the right note p146
Fernando Nottebohm reviews Nature's Music: The Science of Birdsong edited by Peter Marler and Hans Slabbekoorn
doi: 10.1038/435146a
Full Text | PDF (383K)
--------------------------------------------------------------------------------
Science in culture: Womb with a view? p147
All is not as it seems in a television programme on the life of a fetus.
Martin Kemp
doi: 10.1038/435147a
Full Text | PDF (198K)
--------------------------------------------------------------------------------
An autistic look at animals p147
Marian Stamp Dawkins reviews Animals in Translation: Using the Mysteries of Autism to Decode Animal Behaviour by Temple Grandin and Catherine Johnson
doi: 10.1038/435147b
Full Text | PDF (435K)
--------------------------------------------------------------------------------
Don't panic! p148
Joanne Baker reviews The Science of the Hitchhiker's Guide to the Galaxy by Michael Hanlon
doi: 10.1038/435148a
Full Text | PDF (236K)
--------------------------------------------------------------------------------
Top of pageEssay
Concept
Natural symmetry p149
Directional inference: scientific convention applies conclusions from animal studies to humans but not the reverse, contradicting current evidence.
G. A. Bradshaw and Barbara L. Finlay
doi: 10.1038/435149a
Full Text | PDF (150K)
--------------------------------------------------------------------------------
Top of pageNews and Views
Immunology: Insulin trigger for diabetes p151
Type I diabetes occurs when the immune system destroys crucial cells in the pancreas. But what prompts the body to turn against itself so disastrously? It seems that insulin is the key.
Matthias von Herrath
doi: 10.1038/435151a
Full Text | PDF (168K)
See also: Editor's summary
--------------------------------------------------------------------------------
High-energy physics: An emptier emptiness? p152
Temperatures similar to those reached an instant after the Big Bang can be created in collisions of gold atoms. The resulting fireballs may allow us a glimpse of a world that is more symmetrical than our own.
Frank Wilczek
doi: 10.1038/435152a
Full Text | PDF (488K)
--------------------------------------------------------------------------------
100 and 50 years ago p153
doi: 10.1038/435153a
Full Text | PDF (473K)
--------------------------------------------------------------------------------
Developmental biology: Asymmetrical threat averted p155
The somites are embryonic elements that give rise to the muscles, skeleton and some skin layers of the trunk. They form in a symmetrical fashion, but to do so they must be shielded from asymmetrical cues.
Eran Hornstein and Clifford J. Tabin
doi: 10.1038/435155a
Full Text | PDF (147K)
See also: Editor's summary
--------------------------------------------------------------------------------
Planetary science: Magnetic impact craters p156
Aerial surveys of the Vredefort impact crater in South Africa suggest that it is only weakly magnetic. The rocks themselves tell a different story, but does this apply to giant impact basins on Mars?
David J. Dunlop
doi: 10.1038/435156a
Full Text | PDF (234K)
See also: Editor's summary
--------------------------------------------------------------------------------
Sensory physiology: Brainless eyes p157
The visual equipment of box jellyfish includes eight optically advanced eyes that operate with only a rudimentary nervous system. As they produce blurred images, their function remains an open question.
Rüdiger Wehner
doi: 10.1038/435157a
Full Text | PDF (328K)
See also: Editor's summary
--------------------------------------------------------------------------------
Granular media: Information propagation p159
The transmission of force through granular matter such as sand is a crucial consideration in certain applications. The behaviour observed depends on the particle interactions as well as on the length scale involved.
Stefan Luding
doi: 10.1038/435159a
Full Text | PDF (218K)
--------------------------------------------------------------------------------
Obituary: Stanley J. Korsmeyer (1950?2005) p161
H. Robert Horvitz
doi: 10.1038/435161a
Full Text | PDF (116K)
--------------------------------------------------------------------------------
Research highlights p162
doi: 10.1038/435162a
Full Text | PDF (164K)
--------------------------------------------------------------------------------
Top of pageBrief Communications
Robotics: Self-reproducing machines p163
A set of modular robot cubes accomplish a feat fundamental to biological systems.
Victor Zykov, Efstathios Mytilinaios, Bryant Adams and Hod Lipson
doi: 10.1038/435163a
First paragraph | Full Text | PDF (315K) | Supplementary information
See also: Editor's summary
--------------------------------------------------------------------------------
Botany: A record-breaking pollen catapult p164
Joan Edwards, Dwight Whitaker, Sarah Klionsky and Marta J. Laskowski
doi: 10.1038/435164a
First paragraph | Full Text | PDF (153K) | Supplementary information
--------------------------------------------------------------------------------
Top of pageArticles
Retinoic acid signalling links left?right asymmetric patterning and bilaterally symmetric somitogenesis in the zebrafish embryo p165
Yasuhiko Kawakami, ángel Raya, R. Marina Raya, Concepción Rodríguez-Esteban and Juan Carlos Izpisúa Belmonte
doi: 10.1038/nature03512
Abstract | Full Text | PDF (436K) | Supplementary information
See also: Editor's summary | News and Views by Hornstein & Tabin
--------------------------------------------------------------------------------
FGF-induced vesicular release of Sonic hedgehog and retinoic acid in leftward nodal flow is critical for left?right determination p172
Yosuke Tanaka, Yasushi Okada and Nobutaka Hirokawa
doi: 10.1038/nature03494
Abstract | Full Text | PDF (479K) | Supplementary information
See also: Editor's summary | News and Views by Hornstein & Tabin
--------------------------------------------------------------------------------
Top of pageLetters to Nature
A link between prompt optical and prompt -ray emission in -ray bursts p178
W. T. Vestrand, P. R. Wozniak, J. A. Wren, E. E. Fenimore, T. Sakamoto, R. R. White, D. Casperson, H. Davis, S. Evans, M. Galassi, K. E. McGowan, J. A. Schier, J. W. Asa, S. D. Barthelmy, J. R. Cummings, N. Gehrels, D. Hullinger, H. A. Krimm, C. B. Markwardt, K. McLean, D. Palmer, A. Parsons and J. Tueller
doi: 10.1038/nature03515
First paragraph | Full Text | PDF (324K) | Supplementary information
--------------------------------------------------------------------------------
An infrared flash contemporaneous with the -rays of GRB 041219a p181
C. H. Blake, J. S. Bloom, D. L. Starr, E. E. Falco, M. Skrutskie, E. E. Fenimore, G. Duchêne, A. Szentgyorgyi, S. Hornstein, J. X. Prochaska, C. McCabe, A. Ghez, Q. Konopacky, K. Stapelfeldt, K. Hurley, R. Campbell, M. Kassis, F. Chaffee, N. Gehrels, S. Barthelmy, J. R. Cummings, D. Hullinger, H. A. Krimm, C. B. Markwardt, D. Palmer, A. Parsons, K. McLean and J. Tueller
doi: 10.1038/nature03520
First paragraph | Full Text | PDF (310K) | Supplementary information
--------------------------------------------------------------------------------
Albedo of the south pole on Mars determined by topographic forcing of atmosphere dynamics p184
Anthony Colaprete, Jeffrey R. Barnes, Robert M. Haberle, Jeffery L. Hollingsworth, Hugh H. Kieffer and Timothy N. Titus
doi: 10.1038/nature03561
First paragraph | Full Text | PDF (397K)
See also: Editor's summary
--------------------------------------------------------------------------------
Friction enhances elasticity in granular solids p188
C. Goldenberg and I. Goldhirsch
doi: 10.1038/nature03497
First paragraph | Full Text | PDF (339K)
See also: News and Views by Luding
--------------------------------------------------------------------------------
Nonlinear elasticity in biological gels p191
Cornelis Storm, Jennifer J. Pastore, F. C. MacKintosh, T. C. Lubensky and Paul A. Janmey
doi: 10.1038/nature03521
First paragraph | Full Text | PDF (231K)
See also: Editor's summary
--------------------------------------------------------------------------------
Plate-wide stress relaxation explains European Palaeocene basin inversions p195
S?ren B. Nielsen, Erik Thomsen, David L. Hansen and Ole R. Clausen
doi: 10.1038/nature03599
First paragraph | Full Text | PDF (744K)
--------------------------------------------------------------------------------
Palaeomagnetism of the Vredefort meteorite crater and implications for craters on Mars p198
Laurent Carporzen, Stuart A. Gilder and Rodger J. Hart
doi: 10.1038/nature03560
First paragraph | Full Text | PDF (1,696K)
See also: Editor's summary | News and Views by Dunlop
--------------------------------------------------------------------------------
Advanced optics in a jellyfish eye p201
Dan-E. Nilsson, Lars Gislén, Melissa M. Coates, Charlotta Skogh and Anders Garm
doi: 10.1038/nature03484
First paragraph | Full Text | PDF (422K)
See also: Editor's summary | News and Views by Wehner
--------------------------------------------------------------------------------
The flight paths of honeybees recruited by the waggle dance p205
J. R. Riley, U. Greggers, A. D. Smith, D. R. Reynolds and R. Menzel
doi: 10.1038/nature03526
First paragraph | Full Text | PDF (168K)
See also: Editor's summary
--------------------------------------------------------------------------------
The origin of bursts and heavy tails in human dynamics p207
Albert-László Barabási
doi: 10.1038/nature03459
First paragraph | Full Text | PDF (344K) | Supplementary information
See also: Editor's summary
--------------------------------------------------------------------------------
Fast vesicle replenishment allows indefatigable signalling at the first auditory synapse p212
Claudius B. Griesinger, Christopher D. Richards and Jonathan F. Ashmore
doi: 10.1038/nature03567
First paragraph | Full Text | PDF (567K) | Supplementary information
--------------------------------------------------------------------------------
Retinoic acid coordinates somitogenesis and left?right patterning in vertebrate embryos p215
Julien Vermot and Olivier Pourquié
doi: 10.1038/nature03488
First paragraph | Full Text | PDF (428K) | Supplementary information
See also: Editor's summary | News and Views by Hornstein & Tabin
--------------------------------------------------------------------------------
Prime role for an insulin epitope in the development of type 1 diabetes in NOD mice p220
Maki Nakayama, Norio Abiru, Hiroaki Moriyama, Naru Babaya, Edwin Liu, Dongmei Miao, Liping Yu, Dale R. Wegmann, John C. Hutton, John F. Elliott and George S. Eisenbarth
doi: 10.1038/nature03523
First paragraph | Full Text | PDF (330K)
See also: Editor's summary | News and Views by von Herrath
--------------------------------------------------------------------------------
Expanded T cells from pancreatic lymph nodes of type 1 diabetic subjects recognize an insulin epitope p224
Sally C. Kent, Yahua Chen, Lisa Bregoli, Sue M. Clemmings, Norma Sue Kenyon, Camillo Ricordi, Bernhard J. Hering and David A. Hafler
doi: 10.1038/nature03625
First paragraph | Full Text | PDF (271K) | Supplementary information
See also: Editor's summary | News and Views by von Herrath
--------------------------------------------------------------------------------
Enhancement of cellular memory by reducing stochastic transitions p228
Murat Acar, Attila Becskei and Alexander van Oudenaarden
doi: 10.1038/nature03524
First paragraph | Full Text | PDF (296K) | Supplementary information
--------------------------------------------------------------------------------
Corrigendum: Iron and phosphorus co-limit nitrogen fixation in the eastern tropical North Atlantic p232
Matthew M. Mills, Celine Ridame, Margaret Davey, Julie La Roche and Richard J. Geider
doi: 10.1038/nature03632
Full Text | PDF (80K)
--------------------------------------------------------------------------------
Top of pageTechnology Features
PCR: Replicating success p235
PCR often gets taken for granted, but there are ways of making it faster, more accurate and easier to perform. Pete Moore investigates.
Pete Moore
doi: 10.1038/435235a
Full Text | PDF (508K)
--------------------------------------------------------------------------------
Hot from the vent p235
doi: 10.1038/435235b
Full Text | PDF (226K)
--------------------------------------------------------------------------------
Amplifying the signal p236
doi: 10.1038/435236a
Full Text | PDF (225K)
--------------------------------------------------------------------------------
Photocopiers for DNA p237
doi: 10.1038/435237a
Full Text | PDF (144K)
--------------------------------------------------------------------------------
Simplifying the probe set p238
doi: 10.1038/435238a
Full Text | PDF (110K)
--------------------------------------------------------------------------------
Table of suppliers p239
doi: 10.1038/435239a
Full Text | PDF (45K)
--------------------------------------------------------------------------------
Top of pageNaturejobs
Prospects
Generous advice p241
Paul Smaglik
doi: 10.1038/nj7039-241a
Full Text | PDF (128K)
--------------------------------------------------------------------------------
Postdocs
The staff dreams are made of p242
Being the boss is new territory for young investigators. Kendall Powell screens strategies for managing a successful group.
Kendall Powell
doi: 10.1038/nj7039-242a
Full Text | PDF (399K)
--------------------------------------------------------------------------------
Career View
Graduate Journal: Defensive moves p244
Anne Margaret Lee
doi: 10.1038/nj7039-244a
Full Text | PDF (75K)
--------------------------------------------------------------------------------
Scientists & Societies p244
Jacinta Lodge
doi: 10.1038/nj7039-244b
Full Text | PDF (77K)
--------------------------------------------------------------------------------
Movers p244
doi: 10.1038/nj7039-244c
Full Text | PDF (77K)
--------------------------------------------------------------------------------
Top of pageFutures
A life with a semisent p246
Two's company.
Gregory Benford
doi: 10.1038/435246a
Full Text | PDF (186K)
|
上一篇：2005年05月05日 Nature中文摘要 下一篇：2005年05月19日 Nature中文摘要
| |
|
|
|
