| 2006年07月27日 Nature中英文摘要 | 点击： 作者： 来源： 时间： 2006-11-12 本站论坛
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Volume 442 Number 7101 pp329-484 (27 July 2006)
封面故事：锰掺杂砷化镓的扫描隧道显微镜研究
将金属作为“掺杂物”添加进半导体中的做法，被用来调整晶体管和二极管的电子性能。一项新的研究工作，利用在原子精度上取代单个掺杂物的办法来测量它们在纳米尺度上的相互作用。在掺杂锰的砷化镓中铁磁性的发现，激发了人们对基于电子自旋的半导体的兴趣。该研究利用扫描隧道显微镜来观察锰－锰相互作用中所涉及的砷化镓的电子状态。研究人员发现，铁磁相互作用严重依赖于晶体取向，这种性质也许可被用来生长铁磁转变温度超过随机掺杂材料的定向结构。该现象还有可能导致生成用在记忆或信息处理过程中的耦合量子位。（Letter p. 436）封面图片：砷化镓表面上所观测到的锰空穴状态调控自旋状态（箭头所示）之间的磁相互作用。
癌症与炎症之间的一个联系
人们长期寻找的癌症与炎症之间的一个联系已经被发现。由白介素-23（IL-23）（存在于很多人类肿瘤中）诱发的炎症，似乎能通过保护肿瘤不受免疫系统攻击和促进血管形成来帮助肿瘤生长。出生时没有IL-23的小鼠不会患癌症，这同体内IL-23被抗体阻断的小鼠一样，说明对待人类癌症也许可以采取一个类似的策略。
“土卫六”上的甲烷雨
土星的卫星“土卫六”和地球是太阳系中雨能到达地表的唯一地方。不过“土卫六”的雨可能与我们地球上的雨不是很像，因为它是甲烷雨，而且水和甲烷的大气周期是很不同的。本期Nature上两篇论文提供了关于“土卫六”上的雨天会是什么样子的线索。Hueso 和 Sánchez-Lavega利用一个数值模型发现，强甲烷对流风暴伴随着强降雨在某些条件下可能会出现在“土卫六”上。这些甲烷风暴与地球上的山洪暴发可能类似。Tokano等人提供了由搭载在“惠更斯”探测器上的仪器所获得的甲烷分布和温度数据。“惠更斯”最近拍摄了像是河流或河床的景观，但图像中没有任何液体的痕迹。但是，新的大气数据表明，“土卫六”上会下比较小的毛毛雨。与天文望远镜或“卡西尼”飞船所观测到的云形成对比的是，“惠更斯”所碰到的云是普遍存在的，说明降雨是在“土卫六”全球出现的，可能会影响“土卫六”的地表结构。
彗星与星际尘埃的异同
彗星据信是由“脏雪”聚集成的，大约是与太阳系在同一时间形成的。彗星与星际冰在组成上的相似性是引人注目的，说明它们可能起源于星际冰。然而，二者之间也有明显的区别：与分子云相比，彗星中缺少分子氮。或者说，人们是这样认为的。Maret等人利用一种新方法测定了一个致密的分子云中氮的丰度。结果是，他们没有发现分子氮占优势，而是发现原子氮占优势。该发现进一步表明了彗星、陨石、星际尘埃和分子云之间的相似性。由于氮的分解对原子氮来说比对分子氮更大，所以该发现也可以解释在陨石和星际尘埃颗粒中所观测到的同位素异常。
彗星与星际尘埃的异同
彗星据信是由“脏雪”聚集成的，大约是与太阳系在同一时间形成的。彗星与星际冰在组成上的相似性是引人注目的，说明它们可能起源于星际冰。然而，二者之间也有明显的区别：与分子云相比，彗星中缺少分子氮。或者说，人们是这样认为的。Maret等人利用一种新方法测定了一个致密的分子云中氮的丰度。结果是，他们没有发现分子氮占优势，而是发现原子氮占优势。该发现进一步表明了彗星、陨石、星际尘埃和分子云之间的相似性。由于氮的分解对原子氮来说比对分子氮更大，所以该发现也可以解释在陨石和星际尘埃颗粒中所观测到的同位素异常。
三种形式tRNA修饰酶的晶体结构
硫原子对于活细胞的生物合成机制来说有点难以对付，因为它们太活泼，需要采用特殊办法来驯服它们。现在，谷氨酸盐、赖氨酸和谷氨酸tRNA的大肠杆菌 tRNA修饰酶的三种形式的晶体结构已被确定。这种酶在蛋白合成期间对限制核糖体上“三字母”密码子-反密码子摇摆起关键作用，而将硫引入到其34号残体上的尿苷上形成硫尿苷是它发挥这一功能的关键。三种不同结构，让我们看到了将目标U34的位置转移到靠近催化点的地方、同时激发提供硫元素的两个半胱氨酸残体的连续反应是怎样进行的。最后得到的“封闭的”复合物，通过形成一个催化室来将活化点与溶剂屏蔽开来的办法帮助将硫原子准确地纳入到结构中。这可能是将活泼原子放到大分子中精确位置的酶的一个普遍机制。
一种极端喜欢热酸环境的微生物
尽管环境条件极端恶劣，但深海热液喷孔仍是众多微生物的生存之地。不过此前这种环境中还少发现一种生物：地球热酸温泉中生活着喜酸生物，但尽管理论预测在硫化物沉积物中存在酸性小生境，此前从这种沉积物中分离出的所有微生物却都是喜中性的，或者最多是能耐酸的。现在，研究人员终于从一个热液喷孔中分离出了一种极端喜欢热酸环境的微生物。它不是一种细菌，而是古生菌DHVE2（深海热液喷孔广古菌-2）家族的一个成员。它生长在pH值在3.3和 5.8之间、温度在55–75 °C的环境中。它占古生菌种群数量的比例接近15%，所以可能是这些环境中铁和硫循环中的一个主要因素。
关于流感疫情的数值模拟
关于一次潜在的流感爆发事件的流行病学数值模型表明，不存在一剂能够控制流感爆发的灵丹妙药，但将多种方法结合起来有可能减少传播，拯救很多生命。出入境控制不大可能有很大效果，限制国内旅行对控制疫情在国内的传播也几乎不起作用。这些模型预测，英国的一次疫情会在第一个病例发现之后两到三个月内达到高峰，而在四个月内结束。研究还表明，在一次疫情开始之后两个月内就需要有疫苗，这样才能对降低感染率起到较大作用。这意味着，疫苗要发挥作用就需要提前储备。
伤口电流在伤口愈合中所起的作用
在所有试验的动物中，上皮的破坏会产生一个内生的电流，涉及伤口愈合的细胞已知会对所施加的电信号产生响应。科学家对这些由伤口诱导的电流的了解已有 150多年了，但在这些年中的很多年，人们对这种电流在伤口愈合中所起作用基本上是持怀疑态度的。用小鼠和组织培养所做的新的研究工作将调控细胞运动的基因和信号作用通道与伤口愈合对电流的响应联系了起来，因而有可能导致人们对这一有趣的现象有一个更积极的态度。在该发现中居中心地位的分子是 phosphatidylinositol 3'-kinase-γ (PI3Kγ)和肿瘤抑制因子PTEN，它们被发现控制“愈合”细胞朝向由受伤引起的电信号的“向电性”运动。
关于流感疫情的数值模拟
关于一次潜在的流感爆发事件的流行病学数值模型表明，不存在一剂能够控制流感爆发的灵丹妙药，但将多种方法结合起来有可能减少传播，拯救很多生命。出入境控制不大可能有很大效果，限制国内旅行对控制疫情在国内的传播也几乎不起作用。这些模型预测，英国的一次疫情会在第一个病例发现之后两到三个月内达到高峰，而在四个月内结束。研究还表明，在一次疫情开始之后两个月内就需要有疫苗，这样才能对降低感染率起到较大作用。这意味着，疫苗要发挥作用就需要提前储备。
血管内腔是怎样形成的？
上皮管是很多不同组织中的重要结构单元，这些组织包括血管体系。在这些组织中，由于人们对抑制血管生成的物质作为抗癌药物的兴趣，使得它们在药理上也是很重要的。它们精确的形成机制一直难以确定。现在，对活斑马鱼（这种鱼是透明的，因而方便研究）的血管形成所做的高分辨率延时成像研究表明，血管内腔是由细胞内液泡合并形成的，液泡合并后又融合进了胞质膜中。该研究最终为已有一个世纪之久的关于内皮空腔形成的融合模型提供了活体确认，并且最终推翻了关于血管形成的其他模型，消除了人们对细胞培养赝品的担心。
Contents
Editorials
Come veto or high water p329
The obduracy of the White House will slow the progress of stem-cell research in the United States — just as Europe agrees to move forward with it.
doi:10.1038/442329a
Full Text | PDF (120K)
Still not alert p330
Tsunami preparations in the Indian Ocean remain inadequate.
doi:10.1038/442330a
Full Text | PDF (95K)
Let's replicate p330
Post-publication follow-up evolves.
doi:10.1038/442330b
Full Text | PDF (95K)
Top of page
Research Highlights
Research highlights p332
doi:10.1038/442332a
Full Text | PDF (474K)
Top of page
News
Nigeria ready for huge science spend p334
Oil revenues set to establish national research foundation.
Jim Giles
doi:10.1038/442334a
Full Text | PDF (267K)
A long week in stem-cell politics... p335
Europe and the United States still divided over embryo cells.
Meredith Wadman and Alison Abbott
doi:10.1038/442335a
Full Text | PDF (205K)
The lure of stem-cell lines p336
Nature investigates what human embryonic stem-cell lines have been derived worldwide so far, and why scientists are so desperate to work with new ones.
doi:10.1038/442336a
Full Text | PDF (1,078K)
Wildlife caught in crossfire of US immigration battle p338
Crackdown on illegal border crossings puts endangered species at further risk.
Emma Marris
doi:10.1038/442338a
Full Text | PDF (597K)
Sidelines p339
doi:10.1038/442339a
Full Text | PDF (202K)
Carbon credits for the Joneses p340
UK politician advocates domestic emissions allowance.
Jim Giles
doi:10.1038/442340a
Full Text | PDF (64K)
News in brief p341
doi:10.1038/442341a
Full Text | PDF (176K)
Correction p341
doi:10.1038/442341b
Full Text | PDF (176K)
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Business
Break with tradition p342
Traditional medicine has spent decades in the wings of pharmacology. Now India is pushing it to centre stage, as K. S. Jayaraman reports.
doi:10.1038/442342a
Full Text | PDF (554K)
In brief p343
doi:10.1038/442343a
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Market watch p343
doi:10.1038/442343b
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News Features
The trouble with replication p344
The idea that readers should be able to replicate published scientific results is seen as the bedrock of modern science. But what if replication proves difficult or impossible? Jim Giles tracks the fate of one group of papers.
doi:10.1038/442344a
Full Text | PDF (1,291K)
See also: Editor's summary
Bird flu: On border patrol p348
The United States has embarked on a huge effort to try to track the H5N1 avian flu virus in birds migrating into the country. But is surveillance more urgently needed elsewhere? Erika Check reports.
doi:10.1038/442348a
Full Text | PDF (907K)
Lab on a chip: A little goes a long way p351
Faster, safer and easier to control — chemical reactions in microreactors are taking off in the lab. Now industry is being seduced by the charms of the lab on a chip. Jenny Hogan investigates.
doi:10.1038/442351a
Full Text | PDF (391K)
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Correspondence
Hungary: academy is not obsolete or discriminatory p353
György Fábri
doi:10.1038/442353a
Full Text | PDF (108K)
Hungary: academy needs more than internal reform p353
Csaba Szabo
doi:10.1038/442353b
Full Text | PDF (108K)
Quest for seed immortality is mission impossible p353
Andreas Graner and Andreas Börner
doi:10.1038/442353c
Full Text | PDF (108K)
No place for secrets in scientific research p353
Clifford B. Saper
doi:10.1038/442353d
Full Text | PDF (108K)
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Books and Arts
Design flaws p355
Destroying the argument that intelligent design has a scientific basis.
John Tyler Bonner reviews Intelligent Thought: Science Versus the Intelligent Design Movement edited by John Brockman
doi:10.1038/442355a
Full Text | PDF (504K)
See also: Editor's summary
Diary of a weed p356
Anthony Trewavas reviews Seed to Seed: The Secret Life of Plants by Nicholas Harberd
doi:10.1038/442356a
Full Text | PDF (313K)
The body bared p356
doi:10.1038/442356b
Full Text | PDF (234K)
Playing the numbers game p357
David Colquhoun reviews Does Measurement Measure Up? How Numbers Reveal and Conceal the Truth by John M. Henshaw
doi:10.1038/442357a
Full Text | PDF (179K)
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News and Views
Semiconductor physics: Magnetic manipulations p359
A deft technique allows magnetic atoms to be placed one by one in a semiconductor crystal. It's a further step towards an ambitious goal: a computer chip that might simultaneously store and manipulate data.
Nitin Samarth
doi:10.1038/442359a
Full Text | PDF (253K)
See also: Editor's summary
Protein folding: Inside the cage p360
Many newly synthesized bacterial proteins avoid aggregation by folding inside a chaperonin nanocage. Unexpectedly, it turns out that the cage's internal properties can be optimized to accelerate folding.
R. John Ellis
doi:10.1038/442360a
Full Text | PDF (387K)
50 & 100 years ago p361
doi:10.1038/442361a
Full Text | PDF (333K)
Planetary science: Titan's exotic weather p362
Titan is viewed as a sibling of Earth, as both bodies have rainy weather systems and landscapes formed by rivers. But as we study these similarities, Titan emerges as an intriguingly foreign world.
Caitlin A. Griffith
doi:10.1038/442362a
Full Text | PDF (229K)
See also: Editor's summary
Developmental biology: The hole picture p363
What's the best way to make a tube? Roll up a sheet? Hollow out a solid rod? Some innovative movies show how the problem is tackled during the development of blood vessels in embryos.
Keith Mostov and Fernando Martin-Belmonte
doi:10.1038/442363a
Full Text | PDF (275K)
See also: Editor's summary
Astronomy: Revealing flares p364
Transient bursts of cosmic light provide a unique window on what's going on in the distant Universe. But similar bursts closer to home may be muddying the view, and hopes rest on a new tool to resolve things.
J. Anthony Tyson
doi:10.1038/442364a
Full Text | PDF (269K)
Developmental neurobiology: A destructive switch for neurons p365
In the developing nervous system, tremendous multiplication and diversification of cells elaborate the exquisite pattern of the brain. But how do cells shift from early proliferation to assume their mature states?
Peter K. Jackson
doi:10.1038/442365a
Full Text | PDF (407K)
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Insight: Lab on a chip -
Produced with support from:
Insight: Lab on a chip
Lab on a chip p367
Rosamund Daw and Joshua Finkelstein
doi:10.1038/442367a
Full Text | PDF (122K)
The origins and the future of microfluidics p368
George M. Whitesides
doi:10.1038/nature05058
Abstract | Full Text | PDF (592K)
Scaling and the design of miniaturized chemical-analysis systems p374
Dirk Janasek, Joachim Franzke and Andreas Manz
doi:10.1038/nature05059
Abstract | Full Text | PDF (538K)
Developing optofluidic technology through the fusion of microfluidics and optics p381
Demetri Psaltis, Stephen R. Quake and Changhuei Yang
doi:10.1038/nature05060
Abstract | Full Text | PDF (851K)
Future lab-on-a-chip technologies for interrogating individual molecules p387
Harold Craighead
doi:10.1038/nature05061
Abstract | Full Text | PDF (752K)
Control and detection of chemical reactions in microfluidic systems p394
Andrew J. deMello
doi:10.1038/nature05062
Abstract | Full Text | PDF (1,170K)
Cells on chips p403
Jamil El-Ali, Peter K. Sorger and Klavs F. Jensen
doi:10.1038/nature05063
Abstract | Full Text | PDF (1,443K)
Microfluidic diagnostic technologies for global public health p412
Paul Yager, Thayne Edwards, Elain Fu, Kristen Helton, Kjell Nelson, Milton R. Tam and Bernhard H. Weigl
doi:10.1038/nature05064
Abstract | Full Text | PDF (628K)
Article
Snapshots of tRNA sulphuration via an adenylated intermediate p419
Tomoyuki Numata, Yoshiho Ikeuchi, Shuya Fukai, Tsutomu Suzuki and Osamu Nureki
doi:10.1038/nature04896
Abstract | Full Text | PDF (848K) | Supplementary information
See also: Editor's summary
Top of page
Letters
A low fraction of nitrogen in molecular form in a dark cloud p425
S. Maret, E. A. Bergin and C. J. Lada
doi:10.1038/nature04919
First paragraph | Full Text | PDF (222K) | Supplementary information
See also: Editor's summary
Methane storms on Saturn's moon Titan p428
R. Hueso and A. Sánchez-Lavega
doi:10.1038/nature04933
First paragraph | Full Text | PDF (258K) | Supplementary information
See also: Editor's summary | News and Views by Griffith
Methane drizzle on Titan p432
Tetsuya Tokano, Christopher P. McKay, Fritz M. Neubauer, Sushil K. Atreya, Francesca Ferri, Marcello Fulchignoni and Hasso B. Niemann
doi:10.1038/nature04948
First paragraph | Full Text | PDF (177K) | Supplementary information
See also: Editor's summary | News and Views by Griffith
Atom-by-atom substitution of Mn in GaAs and visualization of their hole-mediated interactions p436
Dale Kitchen, Anthony Richardella, Jian-Ming Tang, Michael E. Flatté and Ali Yazdani
doi:10.1038/nature04971
First paragraph | Full Text | PDF (358K) | Supplementary information
See also: Editor's summary | News and Views by Samarth
Widespread active detachment faulting and core complex formation near 13° N on the Mid-Atlantic Ridge p440
Deborah K. Smith, Johnson R. Cann and Javier Escartín
doi:10.1038/nature04950
First paragraph | Full Text | PDF (607K)
A ubiquitous thermoacidophilic archaeon from deep-sea hydrothermal vents p444
Anna-Louise Reysenbach, Yitai Liu, Amy B. Banta, Terry J. Beveridge, Julie D. Kirshtein, Stefan Schouten, Margaret K. Tivey, Karen L. Von Damm and Mary A. Voytek
doi:10.1038/nature04921
First paragraph | Full Text | PDF (431K) | Supplementary information
See also: Editor's summary
Strategies for mitigating an influenza pandemic p448
Neil M. Ferguson, Derek A. T. Cummings, Christophe Fraser, James C. Cajka, Philip C. Cooley and Donald S. Burke
doi:10.1038/nature04795
First paragraph | Full Text | PDF (385K) | Supplementary information
See also: Editor's summary
Endothelial tubes assemble from intracellular vacuoles in vivo p453
Makoto Kamei, W. Brian Saunders, Kayla J. Bayless, Louis Dye, George E. Davis and Brant M. Weinstein
doi:10.1038/nature04923
First paragraph | Full Text | PDF (381K) | Supplementary information
See also: Editor's summary | News and Views by Mostov & Martin-Belmonte
Electrical signals control wound healing through phosphatidylinositol-3-OH kinase-bold gamma and PTEN p457
Min Zhao, Bing Song, Jin Pu, Teiji Wada, Brian Reid, Guangping Tai, Fei Wang, Aihua Guo, Petr Walczysko, Yu Gu, Takehiko Sasaki, Akira Suzuki, John V. Forrester, Henry R. Bourne, Peter N. Devreotes, Colin D. McCaig and Josef M. Penninger
doi:10.1038/nature04925
First paragraph | Full Text | PDF (801K) | Supplementary information
See also: Editor's summary
IL-23 promotes tumour incidence and growth p461
John L. Langowski, Xueqing Zhang, Lingling Wu, Jeanine D. Mattson, Taiying Chen, Kathy Smith, Beth Basham, Terrill McClanahan, Robert A. Kastelein and Martin Oft
doi:10.1038/nature04808
First paragraph | Full Text | PDF (492K) | Supplementary information
See also: Editor's summary
ATM stabilizes DNA double-strand-break complexes during V(D)J recombination p466
Andrea L. Bredemeyer, Girdhar G. Sharma, Ching-Yu Huang, Beth A. Helmink, Laura M. Walker, Katrina C. Khor, Beth Nuskey, Kathleen E. Sullivan, Tej K. Pandita, Craig H. Bassing and Barry P. Sleckman
doi:10.1038/nature04866
First paragraph | Full Text | PDF (483K) | Supplementary information
Degradation of Id2 by the anaphase-promoting complex couples cell cycle exit and axonal growth p471
Anna Lasorella, Judith Stegmüller, Daniele Guardavaccaro, Guangchao Liu, Maria S. Carro, Gerson Rothschild, Luis de la Torre-Ubieta, Michele Pagano, Azad Bonni and Antonio Iavarone
doi:10.1038/nature04895
First paragraph | Full Text | PDF (561K) | Supplementary information
See also: News and Views by Jackson
Molecular architecture of axonemal microtubule doublets revealed by cryo-electron tomography p475
Haixin Sui and Kenneth H. Downing
doi:10.1038/nature04816
First paragraph | Full Text | PDF (393K) | Supplementary information
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Naturejobs
Prospect
Prospects p479
Looking for the best way to balance lab life and family.
Paul Smaglik
doi:10.1038/nj7101-479a
Full Text | PDF (167K)
Special Report
Trial blazers p480
The drug industry may be going through lean times, as new candidates have to clear ever-higher safety hurdles. But this gives scientists who can steer a drug through clinical trials a head start in the job market, says Hannah Hoag.
Hannah Hoag
doi:10.1038/nj7101-480a
Full Text | PDF (605K)
Career Views
Matthias Kleiner, president, DFG, Bonn, Germany p482
Matthias Kleiner is first engineer to head Germany's DFG.
Friederike Siegel
doi:10.1038/nj7101-482a
Full Text | PDF (94K)
Where are the physician-scientists? p482
Physician-scientists wanted.
Alfredo Quiñones-Hinojosa
doi:10.1038/nj7101-482b
Full Text | PDF (94K)
Lab makeover p482
Giving the lab a new look.
Milan de Vries
doi:10.1038/nj7101-482c
Full Text | PDF (94K)
Top of page
Futures
Golden year p484
The gift of memories.
Igor Teper
doi:10.1038/442484a
Full Text | PDF (162K)文字
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