Volume 441 Number 7096 pp785-906 (22 June 2006) 封面故事：治疗失聪的希望人类失聪是由名为Corti的器官中起传感作用的毛细胞的损失造成的。在哺乳动物中，这些细胞不能再生，但在如鸟类等非哺乳脊椎动物中，与毛细胞相邻的支持细胞能够通过“跨越分异”再生丢失的毛细胞。这便提出了一个问题：这种能力是否在哺乳动物身上已经彻底丧失？或者说，该能力仍然处于休眠状态？White等人通过利用新方法来纯化有丝分裂后的小鼠支持细胞，发现这些细胞在体外的确保持着发育成成熟毛细胞的能力。似乎，要求这些细胞再生的信号在活体中要么不存在，要么受到抑制。支持细胞进行增殖的能力随年龄所发生的变化与依赖于周期蛋白的激酶抑制因子p27Kip1的水平有关，这个发现为再生受损的毛细胞提供了一个可能的治疗途径。本期封面所示为转基因小鼠的Corti器官，图上毛细胞用紫色表示，支持细胞用荧光标记为绿色。
一种自授粉的兰花达尔文非常会使用标题，例如“兰花由昆虫授粉的各种不同办法”就能说明这一切。兰花是如何受粉的仍然是一个有丰富内容的话题，本期Nature上报告了名为Holcoglossum amesianum的兰花所表现出的一种开花植物中以前我们不知道的受粉机制。神奇的是，这种雌雄同体的花能将自己的花粉囊旋转360°，将花粉插入自己的柱头空腔中，而不需要任何授粉代理或媒介的帮助。该现象在无风、干旱条件下昆虫很少的时候出现在中国云南省高海拔森林中的树干上，可能是对极端生存环境的一种适应。
关于“拟南芥”等模型生物的文献综述“拟南芥”和“果蝇”等模型生物在实验室中被不断进行基因操纵和选择实验。有了这种实验所产生的数据，一种模型生物的自然遗传变异能告诉我们什么呢？Thomas Mitchell-Olds 和Johanna Schmitt对关于模型植物“拟南芥”（或称“阿拉伯芥”）自然变异的文献进行了综述，他们讨论了最近关于与若干具有重要生态学意义的复合特征有关的基因的发现，为了解基因组演化的机制、地理种群结构和自然种群中DNA所承受的选择压力等提供了线索。
黑洞的增长是一个磁过程我们看不到黑洞，它们是在黑色背景上的黑色。但我们能看到它们在哪里，因为当物质掉进黑洞中时会发出明亮的光。这种盘增长过程是高能天体物理学中很多方面的中心内容，但关于其内部活动情况的观测线索非常少。现在，Miller等人利用由恒星质量黑洞双星体系GRO J1655–40获得的非凡光谱数据，实现了为致密天体上的盘增长之性质确定观测约束条件的这个人们长期以来所寻求的目标。该光谱记录了一定是由一个磁过程提供动力的一个X-射线吸收风，这个磁过程还可通过盘来驱动增长。这表明，以盘的形式向黑洞上的累积增长从根本上说是一个磁过程。
利用硅波导实现宽带放大能同时放大和处理一系列波长通道的与硅兼容的光学元件的开发，是基于光子芯片的未来数据通信技术的关键。此前，这种类型的装置只能够放大单一波长通道。现在，利用为该目的专门设计的纳米尺度的硅波导，Foster等人实现了宽带放大。关键是他们利用了一种被称为“四波混合”的非线性光效应。这个过程还可用于以前只能在很长的光纤中实现的其他全光处理功能。
加州圣安德烈斯断层南段地震活动将增加圣安德烈斯断层南段只是该断层历史上没有断裂过的部分中的一部分。由于这个原因，科学家相信它构成加州最大的地震风险，尽管这个地方构造应力是否真的正在积聚是一个存在激烈争论的话题。Yuri Fialko利用来自雷达干涉测量卫星的数据，生成了该地区表面变形的详细图，该图表明，弹性应力正在以相当高的速度积聚：在过去300年里，已经积累了6-9米的一个位移。这说明，圣安德烈斯断层南段正在接近地震周期的间震期的最后，可以预料某种类型的地震活动将会增加。
动物也注重“形象分”如果我们看到一个人帮助另一个人，我们可能会在今后某个时候更倾向于去帮助利他主义者，而不是去帮助有自私名声的某个人。这种“形象打分”行为被认为有助于维持人与人之间的合作。现在，Redouan Bshary 和 Alexandra Grutter首次提供的实验证据表明，该行为也能稳定非人类的动物之间的合作。在他们的研究中，这种合作行为是由在一种相互关系中能将其伙伴（被称为“顾客”的鱼）身上的体外寄生虫清除掉的清洁鱼表现出来的。清洁鱼既可跟它们的顾客合作，将其身上的体外寄生虫清除掉，也可进行“欺骗”，并且只是简单地去吃其顾客身上的粘液，而将清除寄生虫的事情留给其他清洁鱼去做。一系列的觅食实验表明，顾客鱼会进行“形象打分”，清洁鱼在有一个根据形象进行打分的顾客在场时会表现得更为合作。
构成胸腺的两种组织类型有共同来源胸腺是T细胞的主要来源，T细胞构成防御病毒和癌细胞的免疫系统的主要支柱。胸腺由两种主要上皮细胞类型组成，即皮质细胞和髓质细胞，每种类型的细胞在T细胞选择中执行截然不同的任务。这两种类型的细胞是来自不同祖先还是共同祖先一直存在争议。现在，两个相互独立的研究小组发现，这两种组织类型有一个共同的祖先。一个具有与干细胞相似性质的前体能够生成两种组织的事实，为胸腺疾病的基于细胞的疗法提供了一线希望。
高尔基网络成熟过程的实验观测在细胞生物学的教科书中有两个关于高尔基网络成熟过程的模型：在“传统模型”中，含有货物蛋白的小囊在生产线上从一个囊运动到另一个囊，沿途它们被修饰，直到其被分泌出来；而“囊泡成熟模型”（囊泡是平坦的、盘状膜囊，包括高尔基分泌系统在内）认为，一个单一的高尔基腔室随着时间的推移而发育，使得货物蛋白始终留在一个囊泡中，直到它们做好了被包裹进运送囊中、运送到其最终目的地为止。两个独立的研究小组利用尖端成像技术发现，在酿酒酵母（Saccharomyces cerevisiae）中，这些蛋白在被分泌之前始终留在一个囊泡中。
偶然事件造成的基因表达失控的确是衰老的原因之一由基因组随机损伤所造成的对基因表达的控制的改变，一直被认为是衰老的一个可能的原因。对年轻（6个月）和年老（27个月）的小鼠的心脏组织所做的一项研究，为支持这一理论提供了重要的、但难以获得的数据。该研究首次表明，从小鼠心脏刚刚分离出的细胞的基因表达存在内在的可变性，这种可变性随着年龄的增加而增加。用基因毒性化学物质所做的处理，能够产生与衰老效应类似的现象。该结果表明，由偶然事件所造成的基因表达的失控，是与衰老有关的细胞退化和死亡的一个普遍机制。
中国热河生物群新发现七鳃鳗化石七鳃鳗的化石记录很少见，而且即便存在的化石也难以解释。来自中国白垩纪热河生物群的这个新标本填补了该动物化石记录中一个3亿年的空白，它表明，无颚脊椎动物的这个古代分支是在1亿年前变成其今天这种样子的。
ContentsEditorials
Neuroethics needed p907
Researchers should speak out on claims made on behalf of their science.
doi:10.1038/441907a
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Urgent but balanced p907
Energy problems demand a coherent solution, not a quick fix.
doi:10.1038/441907b
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The mad technologist p908
Hollywood warms to science, but fears technology.
doi:10.1038/441908a
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Research Highlights
Research highlights p910
doi:10.1038/441910a
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News
Tissue-sample payments anger lawmakers p912
Drug company link could hit biobank plans.
Erika Check
doi:10.1038/441912a
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Doomsday food store takes pole position p912
Remote island hosts global seed bank.
Jacqueline Ruttimann
doi:10.1038/441912b
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Sidelines p913
doi:10.1038/441913a
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Open-access journal hits rocky times p914
Financial analysis reveals reliance on philanthropy.
Declan Butler
doi:10.1038/441914a
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Congress pushes plan to make papers free p915
NIH may have to insist on submission to online archive.
Gene Russo
doi:10.1038/441915a
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Plan to rank universities fails to impress p917
Government risks undermining basic research, say critics.
Jim Giles
doi:10.1038/441917a
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Lure of lie detectors spooks ethicists p918
US companies are planning to profit from lie-detection technology that uses brain scans, but the move to commercialize a little-tested method is ringing ethical and scientific alarm bells. Helen Pearson reports.
doi:10.1038/441918a
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News in brief p920
doi:10.1038/441920a
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Correction p921
doi:10.1038/441921a
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News Features
Science in the movies: From microscope to multiplex - An MRI scanner darkly p922
There's more to science at the movies than Lex Luthor's attempts to synthesize kryptonite. In the first of two features on film, John Whitfield looks at how a cinematographic technique can provide insights into the perception of reality. In the second, Alison Abbott meets Ben Heisenberg, a director whose first film is a taut moral fable of laboratory life.
doi:10.1038/441922a
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Science in the movies: From microscope to multiplex - Betrayal at the bench p924
There's more to science at the movies than Lex Luthor's attempts to synthesize kryptonite. In the first of two features on film, John Whitfield looks at how a cinematographic technique can provide insights into the perception of reality. In the second, Alison Abbott meets Ben Heisenberg, a director whose first film is a taut moral fable of laboratory life.
doi:10.1038/441924a
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Conservation biology: The tiger's retreat p927
Tigers are teetering on the verge of extinction and human contact in their habitat could be their greatest threat. Erika Check investigates whether local people can live alongside India's big cats.
doi:10.1038/441927a
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Business
Angling Saxons p931
Eastern Germany is landing major electronics industry investments — but needs to build up its own innovative capacity, reports Ned Stafford.
doi:10.1038/441931a
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Correspondence
Misconduct: lack of action provokes web accusations p932
Shi-min Fang
doi:10.1038/441932a
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Misconduct: exposure is not like Cultural Revolution p932
Zheng Huang
doi:10.1038/441932b
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Misconduct: Chinese funding body unmoved p932
Ushma Savla Neill
doi:10.1038/441932c
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Education and training put Iran ahead of richer states p932
Mohammad Reza Mohebbi and Mehri Mohebbi
doi:10.1038/441932d
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Books and Arts
Lessons from Italy p933
How malaria affected, and was controlled in, Italy in the past century has important messages for today.
Brian Greenwood reviews The Conquest of Malaria: Italy, 1900–1962 by Frank M. Snowden
doi:10.1038/441933a
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Life under the microscope p934
Jane Maienschein reviews The Egg and Sperm Race: The Seventeenth-Century Scientists Who Unravelled the Secrets of Sex, Life and Growth by Matthew Cobb
doi:10.1038/441934a
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Virtually wild p935
doi:10.1038/441935a
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A weird, wired world p935
Vlatko Vedral reviews Entangled World: The Fascination of Quantum Information and Computation edited by Jürgen Audretsch
doi:10.1038/441935b
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News and Views
Animal behaviour: Trust in fish p937
A mutually beneficial interaction between two species of fish turns out to involve the careful appraisal of one by the other — and the appropriately virtuous behaviour by the former while being watched.
Lee Alan Dugatkin
doi:10.1038/441937a
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Astrophysics: Magnetic accretion p938
Disks of hot gas drawn onto a central star or black hole are the best energy-producing machines in the Universe. So how do these accretion disks work? The answer, it seems, is blowing in their winds.
Daniel Proga
doi:10.1038/441938a
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Cell biology: The Golgi grows up p939
The Golgi apparatus of the cell has long baffled biologists, mainly because it is unclear how proteins are conveyed through it on their way to the cell surface. Some innovative microscopy may resolve the issue.
Vivek Malhotra and Satyajit Mayor
doi:10.1038/441939a
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Plant biology: Designs on Rubisco p940
Rubisco is said to be both the most important enzyme on Earth and surprisingly inefficient. Yet an understanding of the reaction by which it fixes CO2 suggests that evolution has made the best of a bad job.
Howard Griffiths
doi:10.1038/441940a
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Materials science: Relaxors go critical p941
Relaxor ferroelectrics are fascinating and useful materials, but they seem to be heterogeneous, hopeless messes. Observing what they do under electric fields reveals critical behaviour that helps to make sense of them.
R. E. Cohen
doi:10.1038/441941a
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Immunology: A second chance for the thymus p942
Each organ develops at its own time — usually in the embryo. The discovery of progenitor cells that give rise to two structures in the thymus hints that this immune organ can continue to develop after birth.
Hans-Reimer Rodewald
doi:10.1038/441942a
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Brief Communications
Pollination: Self-fertilization strategy in an orchid p945
An orchid that flowers in harsh conditions pollinates itself unassisted by any of the usual agents.
Ke-Wei Liu, Zhong-Jian Liu, LaiQiang Huang, Li-Qiang Li, Li-Jun Chen and Guang-Da Tang
doi:10.1038/441945a
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Photonics: Lasers producing tailored beams p946
Eiji Miyai, Kyosuke Sakai, Takayuki Okano, Wataru Kunishi, Dai Ohnishi and Susumu Noda
doi:10.1038/441946a
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Brief Communications Arising
Sleep behaviour: Sleep in continuously active dolphins pE9
Yuske Sekiguchi, Kazutoshi Arai and Shiro Kohshima
doi:10.1038/nature04898
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Sleep behaviour: Activity and sleep in dolphins pE10
Guido Gnone, Tiziana Moriconi and Giorgia Gambini
doi:10.1038/nature04899
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Sleep behaviour: Sleep in continuously active dolphins; Activity and sleep in dolphins (Reply) pE11
O. I. Lyamin, J. Pryaslova, V. Lance and J. M. Siegel
doi:10.1038/nature04900
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Review
Genetic mechanisms and evolutionary significance of natural variation in Arabidopsis p947
Thomas Mitchell-Olds and Johanna Schmitt
doi:10.1038/nature04878
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Letters
The magnetic nature of disk accretion onto black holes p953
Jon M. Miller, John Raymond, Andy Fabian, Danny Steeghs, Jeroen Homan, Chris Reynolds, Michiel van der Klis and Rudy Wijnands
doi:10.1038/nature04912
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The giant electromechanical response in ferroelectric relaxors as a critical phenomenon p956
Z. Kutnjak, J. Petzelt and R. Blinc
doi:10.1038/nature04854
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Broad-band optical parametric gain on a silicon photonic chip p960
Mark A. Foster, Amy C. Turner, Jay E. Sharping, Bradley S. Schmidt, Michal Lipson and Alexander L. Gaeta
doi:10.1038/nature04932
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The Southern Ocean biogeochemical divide p964
I. Marinov, A. Gnanadesikan, J. R. Toggweiler and J. L. Sarmiento
doi:10.1038/nature04883
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Interseismic strain accumulation and the earthquake potential on the southern San Andreas fault system p968
Yuri Fialko
doi:10.1038/nature04797
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A lamprey from the Cretaceous Jehol biota of China p972
Mee-mann Chang, Jiangyong Zhang and Desui Miao
doi:10.1038/nature04730
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Image scoring and cooperation in a cleaner fish mutualism p975
Redouan Bshary and Alexandra S. Grutter
doi:10.1038/nature04755
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Experience-dependent and cell-type-specific spine growth in the neocortex p979
Anthony Holtmaat, Linda Wilbrecht, Graham W. Knott, Egbert Welker and Karel Svoboda
doi:10.1038/nature04783
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Mammalian cochlear supporting cells can divide and trans-differentiate into hair cells p984
Patricia M. White, Angelika Doetzlhofer, Yun Shain Lee, Andrew K. Groves and Neil Segil
doi:10.1038/nature04849
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Clonal analysis reveals a common progenitor for thymic cortical and medullary epithelium p988
Simona W. Rossi, William E. Jenkinson, Graham Anderson and Eric J. Jenkinson
doi:10.1038/nature04813
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Formation of a functional thymus initiated by a postnatal epithelial progenitor cell p992
Conrad C. Bleul, Tatiana Corbeaux, Alexander Reuter, Paul Fisch, Jürgen Schulte Mönting and Thomas Boehm
doi:10.1038/nature04850
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Nanog promotes transfer of pluripotency after cell fusion p997
José Silva, Ian Chambers, Steven Pollard and Austin Smith
doi:10.1038/nature04914
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Golgi maturation visualized in living yeast p1002
Eugene Losev, Catherine A. Reinke, Jennifer Jellen, Daniel E. Strongin, Brooke J. Bevis and Benjamin S. Glick
doi:10.1038/nature04717
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Live imaging of yeast Golgi cisternal maturation p1007
Kumi Matsuura-Tokita, Masaki Takeuchi, Akira Ichihara, Kenta Mikuriya and Akihiko Nakano
doi:10.1038/nature04737
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Increased cell-to-cell variation in gene expression in ageing mouse heart p1011
Rumana Bahar, Claudia H. Hartmann, Karl A. Rodriguez, Ashley D. Denny, Rita A. Busuttil, Martijn E. T. Dollé, R. Brent Calder, Gary B. Chisholm, Brad H. Pollock, Christoph A. Klein and Jan Vijg
doi:10.1038/nature04844
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Smad4 signalling in T cells is required for suppression of gastrointestinal cancer p1015
Byung-Gyu Kim, Cuiling Li, Wenhui Qiao, Mizuko Mamura, Barbara Kasperczak, Miriam Anver, Lawrence Wolfraim, Suntaek Hong, Elizabeth Mushinski, Michael Potter, Seong-Jin Kim, Xin-Yuan Fu, Chuxia Deng and John J. Letterio
doi:10.1038/nature04846
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Naturejobs
Prospect
Prospect p1021
Guidelines for physician-scientists call for training reform.
Paul Smaglik
doi:10.1038/nj7096-1021a
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Special Report
Rules rule p1022
Regulatory affairs is a young profession that's already making its mark in the world of drug development, where one false move can bring years of research to an unwelcome end. If your skills include communication and leadership, it may be for you, says Hannah Hoag.
Hannah Hoag
doi:10.1038/nj7096-1022a
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Careers and Recruitment
Paul Gilna, executive director, Community Cyberinfrastructure for Advanced Marine Microbial Ecology Research and Analysis (CAMERA) project, San Diego, California p1024
Paul Gilna moves on to tackle ocean microbes.
Virginia Gewin
doi:10.1038/nj7096-1024a
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Lessons from the jungle p1024
A trip to Africa inspires future graduate study.
Ayres Christ
doi:10.1038/nj7096-1024b
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Write and wrong p1024
Manuscript writing presents challenges.
Katja Bargum
doi:10.1038/nj7096-1024c
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Futures
Check elastic before jumping p1026
Paralysis of the senses, temporarily.
Neal Asher
doi:10.1038/4411026a
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