| 2005年11月10日 Nature中文摘要 | | 点击： 作者： 来源： 时间： 2006-11-11 本站论坛 |
|  | Volume 438 Number 7065 pp129-256
封面故事：雄性果蝇的同性恋行为
果蝇的“无果实”基因首次被发现是因为突变的雄性表现出同性恋行为。它的基因产物在雄性和雌性之间有所不同，存在于整个中枢神经系统的各组神经元中，但没有发现明显的神经解剖差别。现在，研究人员在果蝇大脑中发现了雄性和雌性有所不同的表达“无果实”基因的一组神经元。这种差别是由主动除去雌性的神经前体细胞产生的。雄性特有的Fru蛋白抑制这种细胞程序死亡，使它们能形成一个神经回路，这个回路引导它们去追求雌性，而不是雄性。这个发现说明了一个特定的基因何以能够引导大脑发育以及随后的与性别有关的行为。在这个例子中，我们可以结合一个已经被发现的神经回路和“性别决定基因”的已经被确定的作用来理解性取向。本期封面所示为这一关键大脑区域中的神经元。
血清素的原始作用
在野外，线虫Caenorhabditis elegans（在寿命研究中常用的一种实验室模型动物）的寿命可能会受到土壤细菌的致病感染的限制。现在，研究人员发现了线虫用来避开这些病原体的一个以前不知道的机制：它能探测这些细菌的气味，并且通过激活在感染后增加调节性神经传输物质血清素含量的特定神经元，它还能够学会将这些细菌的气味与一种危险联系起来。在哺乳动物体内，肠胃中血清素信号作用与化学疗法所造成的恶心有关，血清素受体是防止恶心的药物的主要作用目标。这些新的研究结果说明，血清素在指示肠道疾患中的作用可能是原始的，是在动物漫长进化过程中保留下来的。
NMDA受体及其亚单元的结构
大脑NMDA (N-甲基-D-天门冬氨酸盐)受体涉及包括学习和记忆形成等在内的关键过程，它们丧失功能会导致很多疾病，包括帕金森氏症、精神分裂症和中风。NMDA受体是由NR1 和 NR2 亚单元组成的离子通道蛋白，但人们不知道这些亚单元是怎样排列的。现在，Furukawa等人报告了一个NR1/NR2A异二聚物的氨基乙酸和谷氨酸盐结合区域的高分辨率晶体结构，以及与谷氨酸盐形成复合物的NR2A亚单元的高分辨率晶体结构。该结构证实，NR1/NR2A异二聚物是NMDA受体中的基本功能单元，NR1的酪氨酸 535 （位于该亚单元界面中）是控制受体去活化率的一个地点。
木星大气层中带状风的数学模型
木星大气层中的特征带是由两种基本类型的强风构成的一个涉及木星全球的体系产生的，这两种基本类型的风分别是很宽的向东吹的赤道喷射流和范围较小的、纬度较高的喷射流，后者向交替方向流动。研究人员开发出一个新的数学模型，它在以前的模型失败的地方获得了成功，即它能同时产生两个居主导地位的带状风模式。
用太阳周期解释Dansgaard–Oeschger事件的周期
Dansgaard–Oeschger事件是在上次冰期期间和末期非常有规律性地发生的迅速的气候波动：在距今110000年和23000年间发生23次这种事件，周期为1470年。如果能够识别造成这种周期的原因，就有可能弄清是什么触发了这些事件。过去，太阳作为一个可能的原因被排除在外，这是因为在太阳变化的记录中缺少一个时间为1470年的光谱内容。尽管如此，Braun等人还是提出了一个新的假设，它令人信服地将1470年周期解释为两个著名的太阳周期的净结果。这两个著名的太阳周期是DeVries 和 Gleissberg周期，周期长度分别为87年和210年。
地震开始时的情况影响最后强度
在瀑布模型（对地震是如何开始的所做的一个被广泛接受的解释）中，滑动在一小块断层上开始，在条件适合时继续沿一个断层平面断裂。这一多米诺骨牌式的理论的含义是，小地震是与大地震相同的方式开始的，地震的大小在断裂停止前是无法确定的。对日本、台湾、加州和阿拉斯加的地震所做的新的观测表明，与该理论预测相反的是，地震开始的过程强烈影响最后的震级。在地震断裂开始后最初的几秒内所释放出的能量的频率与地震强度之间有一个缩放比例关系。了解这一过程的物理问题，将使得在不知道一个断层平面周围应力状态的情况下预测地震强度成为可能。
岛屿上的物种是怎么来的？
生物学家早就把岛屿当作了解生命分异的天然实验室。从这些研究中（尤其是Ernst Mayr所做的研究）获得的一个结论是，偏远群岛上的生命是从移居生物由大陆向岛屿的简单的单向流动中积累起来的。Filardi 和 Moyle通过估计一个泛太平洋鸟群（这种鸟的名称为monarch flycatchers，在Mayr的研究工作中有它们）在时空上的关系来检验这一假设。它们的分子种类史数据表明，关于岛屿的传统观点（即把岛屿当成是踏脚石，认为物种是通过以在各个岛屿上跳跃的方式越过海洋到达大洋洲及太平洋岛屿的）与事实不符。实际上，物种向太平洋主要群岛上的分布是一个物种辐射过程造成的，这个过程既涉及物种从岛屿向大陆迁移，也涉及相反的过程。
自然变异受很多因素的限制
用果蝇的12个不同种系所做的一项实验表明，自然出现的突变以快的惊人的速度产生大量基因表达变异。让自然突变（只有弱的有害效应或没有有害效应）积累仅仅200代，基因表达的演化就能在占总数40%的基因中检测到。这种变异有促进演化的可能，但将所观察到的演化速度与物种之间的差异所做的比较表明，自然变异受物理的、发育的或其他一些因素的限制。
Gigaxonin是一种新型“泛素-脚手架蛋白”
“巨大轴索性神经病”（GAN）是一种罕见的疾病，出现在孩童时代的早期。它是由GAN基因的突变引起的，该基因编码gigaxonin，这是BTB/kelch细胞骨架蛋白超级家族的一个成员。这一细胞骨架网络的改变是一些较常见疾病的一个特点，这些疾病包括“肌萎缩性(脊髓) 侧索硬化”，所以科学家对gigaxonin的功能很有兴趣，因为它也许可提供关于一般性神经退化疾病发病机理的线索。现在，研究人员发现gigaxonin是一种新型“泛素-脚手架蛋白”，是神经功能所必需的，通过对与微管相关的蛋白1B的光链降解的控制来生存。
细胞层次上的生物节律
多数动物细胞即使在组织培养中也能形成分子振荡，它们是生物节律的基础。要将这一能力用到在整个生物体中所看到的复杂的、与时间有关的行为模式中需要一系列各自独立的大脑振荡体的干预。果蝇被证明是研究这一体系的一个好模型。果蝇表现出特征性的早、晚运动活性，每个由不同的一组成年大脑时钟神经元控制。现在，通过培养在这些早、晚细胞中有不同节律周期的转基因动物，研究人员发现，大脑时钟细胞被组织进两个单独的神经回路中。一个回路包括早细胞和晚细胞，驱动生物运动活性节律。晚细胞的时间是由早细胞决定的，因为每天都有一个从早细胞到晚细胞的复位信号，复位后，信号之间的节奏又恢复到由遗传密码所编好的程序。
科学家积极探寻不用动物进行毒性试验的方法
定于2007年生效的欧盟的一项法令，可能要求制造商们必须对在如化妆品等日用品中所使用的数百种化学物质进行毒性试验。如果采用传统方法，将会大大增加要死在毒性试验中的动物的数量。所以，研究人员正在积极寻找合适的不用动物的毒性试验方法。
Editorials
DARPA dreaming p129
Replicating the success of the US Defense Advanced Research Projects Agency (DARPA), in an organization devoted to energy research, will be easier said than done.
doi:10.1038/438129a
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A less toxic solution p129
Industry should get behind a European partnership that will explore alternatives to animal testing.
doi:10.1038/438129b
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Flu in circulation p130
An interim US rule on safeguards may not, on its own, be enough to contain the 1918 flu virus.
doi:10.1038/438130a
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Top of pageResearch Highlights
Research highlights p132
doi:10.1038/438132a
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Top of pageNews
Deadly flu virus can be sent through the mail p134
US lab agrees to share reconstructed pandemic strain.
Andreas von Bubnoff
doi:10.1038/438134a
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Far East lays plans to be stem-cell hotspot p135
Asia seeks to capitalize on home-grown expertise.
David Cyranoski
doi:10.1038/438135a
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Sidelines p136
doi:10.1038/438136a
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Researchers break the rules in frustration at review boards p136
Experiments on human subjects go ahead without official approval, says survey.
Jim Giles
doi:10.1038/438136b
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Boeing strike leaves satellites stranded on launch pad p137
Rocket mechanics down tools over healthcare dispute.
Geoff Brumfiel
doi:10.1038/438137a
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Antigravity craft slips past patent officers p139
'Impossible' device gets seal of approval.
Philip Ball
doi:10.1038/438139a
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Bush buries US bunker-buster project p139
Plans for ground-penetrating nuclear warhead scrapped.
Geoff Brumfiel
doi:10.1038/438139b
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Congress attacked over species bill p140
Conservationists rally in face of law reforms.
Rex Dalton
doi:10.1038/438140a
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News in brief p142
doi:10.1038/438142a
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Top of pageNews Features
Animal testing: More than a cosmetic change p144
Commercial and political pressures are pushing for a halt to the use of animals in toxicology tests in Europe. This change will also mean a move towards better science, says Alison Abbott.
doi:10.1038/438144a
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Linguistics: Tongue tied p148
Endangered languages often contain key linguistic insights found nowhere else. But the tongues are disappearing faster than scientists can document them. Jessica Ebert reports.
doi:10.1038/438148a
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Psychiatric disease: All in the mind of a mouse p151
Could mice with faulty genes help us to understand the biology of psychiatric disease? Carina Dennis investigates.
doi:10.1038/438151a
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Top of pageBusiness
Path to approval proves rocky for copycat biodrugs p154
Attempts to copy the first generation of biotechnology drugs are facing fierce resistance, as Meredith Wadman reports.
Meredith Wadman
doi:10.1038/438154a
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In brief p155
doi:10.1038/438155a
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Market Watch p155
Colin Macilwain
doi:10.1038/438155b
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Top of pageCorrespondence
Biodiversity needs the help of global change managers, not museum-keepers p156
Pierre L. Ibisch, Michael D. Jennings and Stefan Kreft
doi:10.1038/438156a
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Biodiversity: journals must take a broader view p156
Justin Gerlach
doi:10.1038/438156b
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Biodiversity: saving Florida panther makes sense p156
Laura Hartt
doi:10.1038/438156c
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Top of pageAutumn Books
Peaks in climate research p157
Lonnie Thompson climbs every mountain to look for clues to climate change.
Georg Hoffmann reviews Thin Ice: Unlocking the Secrets of Climate in the World's Highest Mountains by Mark Bowen
doi:10.1038/438157a
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Magnetic personalities p158
David W. Hughes reviews Fatal Attraction: Magnetic Mysteries and the Enlightenment by Patricia Fara
doi:10.1038/438158a
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A poisoned reputation p158
John Cornwell reviews Between Genius and Genocide: The Tragedy of Fritz Haber, Father of Chemical Warfare by Daniel Charles
doi:10.1038/438158b
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Short cut to space-time p159
Jim Al-Khalili reviews A Briefer History of Time by Stephen Hawking and Leonard Mlodinow
doi:10.1038/438159a
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Science in society p161
Daniel J. Kevles reviews Victory and Vexation in Science: Einstein, Bohr, Heisenberg and Others by Gerald Holton
doi:10.1038/438161a
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The making of a genius p162
Mark Lythgoe reviews The Creating Brain: The Neuroscience of Genius by Nancy C. Andreasen
doi:10.1038/438162a
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Digging for clues p163
Jennifer Clack reviews Discovering Dorothea: The Life of the Pioneering Fossil-Hunter Dorothea Bate by Karolyn Shindler
doi:10.1038/438163a
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A Stone Age greenhouse p165
Robert J. Charlson reviews Plows, Plagues and Petroleum: How Humans Took Control of Climate by William F. Ruddiman
doi:10.1038/438165a
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Sticking with nature p166
R. McNeill Alexander reviews The Gecko's Foot. Bio-inspiration: Engineered from Nature. by Peter Forbes
doi:10.1038/438166a
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Top of pageNews and Views
Neurobiology: Triggers for channel opening p167
Fast transmission between nerve cells relies on specialized ion channels. Probing the structure of these proteins reveals how the binding of a neurotransmitter causes the communication channels to open.
Cynthia Czajkowski
doi:10.1038/438167a
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Materials Science: Erasing electron mass p168
Two-dimensional graphite could be useful in carbon-based electronic devices. How electrons move in these structures seems best described by relativistic quantum physics, modelling them as if they have no mass at all.
Charles L. Kane
doi:10.1038/438168a
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Microbiology: RAMP resistance p170
There is an urgent need for new antimicrobial agents because antibiotic resistance has become so prevalent. But a promising class of such agents, known as RAMPs, may suffer from the same problem.
Angus Buckling and Michael Brockhurst
doi:10.1038/438170a
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Seismology: The start of something big? p171
Can we predict the final size of an earthquake from observations of its first few seconds? An extensive study of earthquakes around the Pacific Rim seems to indicate that we can — but uncertainties remain.
Rachel Abercrombie
doi:10.1038/438171a
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Circadian rhythms: Clock coordination p173
Many animals concentrate their activity around dawn and dusk. This timing is regulated by distinct 'morning' and 'evening' oscillators in the central nervous system. But how are these two neuronal clocks coordinated?
Michael N. Nitabach
doi:10.1038/438173a
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50 & 100 years ago p175
doi:10.1038/438175a
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Top of pageBrief Communications
Gravitational tractor for towing asteroids p177
A spacecraft could deflect an Earth-bound asteroid without having to dock to its surface first.
Edward T. Lu and Stanley G. Love
doi:10.1038/438177a
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Green chemistry: Biodiesel made with sugar catalyst p178
Masakazu Toda, Atsushi Takagaki, Mai Okamura, Junko N. Kondo, Shigenobu Hayashi, Kazunari Domen and Michikazu Hara
doi:10.1038/438178a
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Top of pageBrief Communications Arising
Neuroscience: Rewiring the adult brain pE3
Michael B. Calford, Yuzo M. Chino, Aniruddha Das, Ulf T. Eysel, Charles D. Gilbert, Stephen J. Heinen, Jon H. Kaas and Shimon Ullman
doi:10.1038/nature04359
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Neuroscience: Rewiring the adult brain (Reply) pE3
Stelios M. Smirnakis, Michael C. Schmid, Alyssa A. Brewer, Andreas S. Tolias, Almut Schüz, Mark Augath, Werner Inhoffen, Brian A. Wandell and Nikos K. Logothetis
doi:10.1038/nature04360
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Top of pageArticles
Pathogenic bacteria induce aversive olfactory learning in Caenorhabditis elegans p179
Yun Zhang, Hang Lu and Cornelia I. Bargmann
doi:10.1038/nature04216
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Subunit arrangement and function in NMDA receptors p185
Hiroyasu Furukawa, Satinder K Singh, Romina Mancusso and Eric Gouaux
doi:10.1038/nature04089
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Top of pageLetters
Simulation of equatorial and high-latitude jets on Jupiter in a deep convection model p193
Moritz Heimpel, Jonathan Aurnou and Johannes Wicht
doi:10.1038/nature04208
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Two-dimensional gas of massless Dirac fermions in graphene p197
K. S. Novoselov, A. K. Geim, S. V. Morozov, D. Jiang, M. I. Katsnelson, I. V. Grigorieva, S. V. Dubonos and A. A. Firsov
doi:10.1038/nature04233
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Experimental observation of the quantum Hall effect and Berry's phase in graphene p201
Yuanbo Zhang, Yan-Wen Tan, Horst L. Stormer and Philip Kim
doi:10.1038/nature04235
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A record of Permian subaqueous vent activity in southeastern Brazil p205
Jorge Kazuo Yamamoto, Thomas Rich Fairchild, Paulo Cesar Boggiani, Tarcísio Jose Montanheiro, Carlos César de Araújo, Pedro Kunihiko Kiyohara, Sergio Luis Fabris de Matos and Paulo César Soares
doi:10.1038/nature04252
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Possible solar origin of the 1,470-year glacial climate cycle demonstrated in a coupled model p208
Holger Braun, Marcus Christl, Stefan Rahmstorf, Andrey Ganopolski, Augusto Mangini, Claudia Kubatzki, Kurt Roth and Bernd Kromer
doi:10.1038/nature04121
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The deterministic nature of earthquake rupture p212
Erik L. Olson and Richard M. Allen
doi:10.1038/nature04214
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Single origin of a pan-Pacific bird group and upstream colonization of Australasia p216
Christopher E. Filardi and Robert G. Moyle
doi:10.1038/nature04057
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A mutation accumulation assay reveals a broad capacity for rapid evolution of gene expression p220
Scott A. Rifkin, David Houle, Junhyong Kim and Kevin P. White
doi:10.1038/nature04114
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Gigaxonin-controlled degradation of MAP1B light chain is critical to neuronal survival p224
Elizabeth Allen, Jianqing Ding, Wei Wang, Suneet Pramanik, Jonathan Chou, Vincent Yau and Yanmin Yang
doi:10.1038/nature04256
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Fruitless specifies sexually dimorphic neural circuitry in the Drosophila brain p229
Ken-Ichi Kimura, Manabu Ote, Tatsunori Tazawa and Daisuke Yamamoto
doi:10.1038/nature04229
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Suppression of Polycomb group proteins by JNK signalling induces transdetermination in Drosophila imaginal discs p234
Nara Lee, Cédric Maurange, Leonie Ringrose and Renato Paro
doi:10.1038/nature04120
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A resetting signal between Drosophila pacemakers synchronizes morning and evening activity p238
Dan Stoleru, Ying Peng, Pipat Nawathean and Michael Rosbash
doi:10.1038/nature04192
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Principal pathway coupling agonist binding to channel gating in nicotinic receptors p243
Won Yong Lee and Steven M. Sine
doi:10.1038/nature04156
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Cis–trans isomerization at a proline opens the pore of a neurotransmitter-gated ion channel p248
Sarah C. R. Lummis, Darren L. Beene, Lori W. Lee, Henry A. Lester, R. William Broadhurst and Dennis A. Dougherty
doi:10.1038/nature04130
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Top of pageNaturejobs
Prospect
The hands that guide p253
Good mentors deserve wider recognition.
Paul Smaglik
doi:10.1038/nj7065-253a
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Career Views
Steven Williams, president, Wildlife Management Institute, Washington DC p254
Wildlife biologist goes back to conservation.
Virginia Gewin
doi:10.1038/nj7065-254a
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Mentors & Protégés p254
Mentor helps students even during busy times.
Joyce Tung
doi:10.1038/nj7065-254b
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Graduate journal: Post-holiday revelations p254
A return to the lab brings fresh revelations.
Tobias Langenhan
doi:10.1038/nj7065-254c
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Top of pageFutures
The crime of the century p256
A little family planning.
Geoff Brumfiel
doi:10.1038/438256a
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