Volume 439 Number 7072 pp1-116封面故事：蜜蜂行为方式的演化起源本期封面所示为两只蜜蜂在采花粉：左边为一只独行的雌蜜蜂，它把花粉当作自己窝里幼蜂们的一个蛋白来源；与它一起采花粉的是一只不能生育的“完全社会性的”工蜂。这两只雌蜂的社会生物学行为是不同的，但它们的行为的演化起源却是一样的。完全社会性的生活方式涉及照顾自己年幼的“弟弟妹妹”们的不能生育的工蜂。对这种行为是怎么出现的有一个解释，它涉及对母方生殖特征的选择。用蜜蜂所做的实验证实了这种可能性。有趣的是，工蜂行为的差异可由生殖特点的差异来解释。如果选择了爱采花粉而不是花蜜的特征，那么所得到的工蜂就具有较高的生殖潜力（一般来说是未表达的生殖潜力）。同样，未被选择的具有较高生殖潜力的蜜蜂喜欢采花粉。这意味着，母方的特征在独行的蜜蜂和包含工蜂的蜂群之间能起一个演化上的桥头堡的作用。
深海渔业资源的可持续性管理迫在眉睫用来区分海洋鱼类物种是安全还是濒危的IUCN（国际自然与自然资源保护联合会）标准已被首次用于深海鱼类，并获得了令人震惊的结果。在一个为期17年的时间段中，加拿大西北大西洋水域中的5种深海鱼类的状况已经恶化到了符合IUCN“严重濒危”标准的程度。这表明，需要采取紧急措施，对深海渔业资源进行可持续性管理。
副流感病毒5F融合蛋白融合前状态的晶体结构流感、HIV和副黏液病毒等包膜病毒对一个细胞的感染需要病毒膜和细胞膜的融合。涉及这一过程的很多病毒蛋白是高度“专业”的。首先，它们以一个亚稳态的形状出现，这个形状能储存进入细胞所需的能量；然后，该蛋白形状所发生的不可逆转的变化促成膜的融合。现在，研究人员确定了副流感病毒5F融合蛋白在其融合前状态的晶体结构。融合前和融合后状态的很多差别反映了膜融合机制的详细情况，这对于研究防止病毒感染的新方法可能具有价值。
纳米颗粒自组装合成技术的新进展将由两种不同材料构成的纳米颗粒组装成一个二元纳米颗粒超晶格，是合成大量具有精确控制的化学组成和构成成分紧密定位的各种不同材料（超材料）的一种很有希望的方法。在理论上，只有少数稳定的二元超晶格能由硬球来组装，从而潜在限制了这种方法的应用。但并非完全没有希望，因为在纳米尺度，有额外的力（如静电力、分子间力和偶极力等）来稳定二元纳米颗粒结构。现在，Shevchenko等人报告，他们由金属、半导体、磁性和电介质纳米颗粒的各种不同组合合成了十几种新结构。这一成果显示了自组装在设计具有可编程物理和化学性质的不同类别的新型材料和超材料方面所具有的潜力。
宇宙中核合成反应的发生地点放射性同位素铝-26的半衰期较短，约为72万年，所以我们能够检测到铝-26典型的伽马射线的事实，是当前核合成（即新原子核的生成）正在我们的银河系中发生的一个很好的指示。现在，由欧洲航天局的INTEGRAL天文望远镜所进行的一次伽马射线调查，为解决关于这种核合成发生地点的一个争论很久的问题提供了分辨率足够高的数据。关键的发现是，铝-26源与银河系共同转动。这个发现支持认为其来源是分布在整个银河系中的巨大恒星、而不是局部的恒星形成区域的观点。
又一次掩星现象被观测到掩星现象（当一个太阳系的天体从我们地球与一个恒星之间经过、并将其光线遮挡住时的现象）是天文学家们迫切等待的，因为它们提供了一个进行正常情况下不可能进行的测量工作的机会。自从冥王星的卫星Charon所产生的一次掩星现象被观测到以来，已经有25年没有观测到这种现象了。但在2005年7月11日，出现了另一次掩星现象，这次整个南美洲的天文台都处在理想的观测位置。所得到的数据被用来对Charon的半径进行准确测量，结果是接近605公里，并为该天体的大气密度确定一个上线（是一个相当低的上线）。请访问tinyurl.com/9c56s这个站点，观看用QuickTime技术拍摄的一部关于该事件的影片。
海洋与全球变暖发生在5500万年前的古新世末期的一个全球变暖事件，正在为我们提供一幅地球如何对气候变化做出响应的画面。当时，气温的迅速上升伴随着海洋和陆地生物圈的迅速变化以及海洋化学和环流的变化。用碳同位素记录所做的一项研究，显示了深水形成地点从南半球向北半球的一次转变，这个转变是在几千年时间内引发的，但可能持续了至少4万年。这表明，温室条件能诱发深层海洋环流的变化，这种变化可以迅速地被引发，但要逆转它所需要的时间却要长的多。
“束毛藻”从膦酸盐获取磷的方式固氮菌“束毛藻”（Trichodesmium）是热带和亚热带海洋中主要的“新”氮来源，但我们对能使这些细菌得以存活的细胞方面所发生的适应性变化却知之甚少。“束毛藻”能在北大西洋西部这样的溶解的有机磷酸盐含量较低的水域生存，这一事实表明，它是一种有效的磷酸盐清除者，能够利用溶解的有机磷。这一假设被在“马尾藻海”（Sargasso Sea）进行的一项新的研究所证实。“束毛藻”似乎是利用一种C-P裂解酶来从膦酸盐化合物中获取磷的。这种类型的化学键长期以来被认为是难以断开的，但控制膦酸盐代谢的基因存在于“红海束毛藻”（T. erythraeum）基因组和所有目前已经试验过的“束毛藻”物种中。
乳腺干细胞分离成功乳腺干细胞的存在是从对人类乳腺组织的遗传分析结果、以及从小鼠的乳腺能从组织碎片再生的事实推断出的。现在，两个小组报告，他们从小鼠身上分离出了乳腺干细胞。Shackelton等人报告了一种分离方法，该方法是基于为干细胞功能引入一个标记。于是，来自分离出的这组细胞中的一个细胞便显示了其威力：它在活体中再生了一个完整的乳腺。这组细胞在一个恶化前的乳腺肿瘤模型中能够增殖，从而为乳腺癌干细胞的概念提供了支持。在网上发表的一篇论文中，Stingle等人报告，他们利用一种强大的有限稀释移植方法，将罕见的一个亚组的成年小鼠乳腺细胞纯化到了近乎同质的程度，这些细胞能在6个星期内在活体中独自再生一个完整的乳腺。
人为什么不选择“摆动跑”？人类的腿能够迈出的步态有无数个，而我们从中所选择的是要么走，要么跑。这是因为走和跑是能量效率最大的两种步态吗？Srinivasan 和 Ruina用一个计算模型对无数不同的步态进行了分析评估，其做法是将它们套用到简单的牛顿力学原理中去，计算不同步态移动同样质量所需的能量大小。他们发现，走、跑和由二者结合起来形成的一种被称为“摆动跑”的步态每个都有其作为最佳步态时的一个速度值。然而，真实的人是根本不会选择“摆动跑”的，所以由这个模型所获得的简化了的运动情形可能忽略了使得“摆动跑”在真实世界中不现实的因素。
将siRNA用于性病防治的可能性由“小干涉RNA”（siRNA）所进行的基因沉默参与很多生物过程，它有可能成为一个重要的治疗形式，但一个主要障碍是难以将siRNA送进细胞中。现在，Palliser等人报告，他们将siRNA有效地送进了小鼠的阴道中，以保护它们不受致命的生殖器单纯疱疹病毒-2的感染。研制一种杀菌剂来防止性病传播是遏制艾滋病传播的一项优先工作，单纯疱疹病毒-2感染是艾滋病病毒传播的一个重要的共因子。这项研究表明， 也许有可能把siRNA作为一种阴道杀菌剂的活性成分，来防止病毒传播、治疗感染或防止性传播病毒的复发。
Caspase 8与成神经细胞瘤的关系基因改变在进攻性成神经细胞瘤（儿童最常见的固体肿瘤形式）中普遍存在。尤其是，凋亡蛋白酶caspase 8的删除或抑制在恶性、扩散性疾病中普遍存在。用成神经细胞瘤细胞系所做的实验显示，caspase 8对肿瘤初次形成没有影响，而是阻止随后的组织入侵和转移。它是作为一种转移抑制因子与粘合素一起发挥作用的，调控入侵性成神经细胞瘤细胞的存活状况和恶性程度。
Editorials
No new start at Los Alamos p1
A fresh contract for the management of the New Mexico nuclear-weapons laboratory offers it little prospect of a happy and prosperous new year.
doi:10.1038/439001a
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Developing resistance p1
A study of opposition to a vaccine for children shows how the public can lose faith in science.
doi:10.1038/439001b
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Sound science p2
Audio files downloaded from the Internet can enrich scientific communication.
doi:10.1038/439002a
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Top of pageResearch Highlights
Research highlights p4
doi:10.1038/439004a
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Top of pageNews
Mashups mix data into global service p6
Is this the future for scientific analysis?
Declan Butler
doi:10.1038/439006a
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Intelligent design verdict set to sway other cases p6
Failure in court sets offers evolutionary precedent.
Emma Marris
doi:10.1038/439006b
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Croatian scientists call for openness over funding p7
Researchers demand transparency for grant awards.
Alison Abbott
doi:10.1038/439007a
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Blow follows blow for stem-cell work p8
South Korean cloning scandal deepens.
David Cyranoski
doi:10.1038/439008a
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Los Alamos bosses ditched after decade of scandals p8
US weapons lab makes a fresh start.
Emma Marris
doi:10.1038/439008b
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News in brief p9
doi:10.1038/438902a
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Top of pageNews Features
Our Universe: Outrageous fortune p10
A growing number of cosmologists and string theorists suspect the form of our Universe is little more than a coincidence. Are these harmless thought experiments, or a challenge to science itself? Geoff Brumfiel investigates.
doi:10.1038/439010a
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Ethiopia: Awash with fossils p14
The Afar region of Ethiopia is littered with traces of the earliest humans. Rex Dalton gets on the trail with a team of devoted experts who just live for the next find.
doi:10.1038/439014a
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Top of pageBusiness
More than just hot air? p17
With the launch of an alternative-energy division, BP is taking steps to show that it is serious about 'clean' technology. Emma Marris reports.
doi:10.1038/439017a
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Top of pageCorrespondence
Power games cause sparks in physics, but biologists have learnt from evolution p18
Peter Hietz and Manuela Winkler
doi:10.1038/439018a
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Power clashes limit science and reflect archaic values p18
María Uriarte, Kathleen Weathers and Valerie Eviner
doi:10.1038/439018b
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Science is an adventure, not a battle p18
David Kleinfeld
doi:10.1038/439018c
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Bias may be unintentional but it's still there p18
Cathy W. S. Chen and Ying-Hen Hsieh
doi:10.1038/439018d
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Top of pageBooks and Arts
A robust approach p19
The functional overlap between different components protects biological systems.
Eörs Szathmáry reviews Robustness and Evolvability in Living Systems by Andreas Wagner
doi:10.1038/439019a
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Psychology in the real world? p20
Steve Blinkhorn reviews World As Laboratory: Experiments with Mice, Mazes, and Men by Rebecca Lemov
doi:10.1038/439020a
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Exhibition: Casting a long shadow p21
Laura Spinney reviews Melancholy: Genius and Insanity in the West
doi:10.1038/439021a
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Top of pageNews and Views
Developmental neuroscience: Two gradients are better than one p23
Wiring up retinal neurons to the correct brain region during development is a feat of precision growth. A novel directional cue repels retinal neuron fibres, acting as a counterbalance to a known attractive signal.
Liqun Luo
doi:10.1038/439023a
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Planetary science: The ferryman casts his shadow p24
The most accurate way of determining the size of some bodies in the Solar System is to observe them as they pass across the face of a star. In the case of Charon, Pluto's largest satellite, it's been a long wait.
David J. Tholen
doi:10.1038/439024a
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Oceanography: A phosphate alternative p25
A major player among the phytoplankton can exploit a source of phosphorus previously thought to be unavailable to it. That ability may provide an ecological advantage in nutrient-depleted regions of the open ocean.
Sergio A. Sañudo-Wilhelmy
doi:10.1038/439025a
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Volcanoes: Interpreting inclusive evidence p26
Crystallization of ascending magma may affect the style of volcanic activity. Pockets of melt incorporated into crystals provide windows on processes that occur several kilometres below Earth's surface.
Julia E. Hammer
doi:10.1038/439026a
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Biological physics: Harmonies from noise p27
Do random environments make for random responses to them? Mathematical models suggest that this is not always the case — adding noise could create synchronous oscillations in cell–cell signalling systems.
Michael Springer and Johan Paulsson
doi:10.1038/439027a
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50 & 100 years ago p28
doi:10.1038/439028a
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Top of pageBrief Communications
Fisheries: Deep-sea fishes qualify as endangered p29
A shift from shelf fisheries to the deep sea is exhausting late-maturing species that recover only slowly.
Jennifer A. Devine, Krista D. Baker and Richard L. Haedrich
doi:10.1038/439029a
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Top of pageBrief Communications Arising
Ecology: Mechanisms for consumer diversity pE1
Takehito Yoshida, Laura E. Jones, Stephen P. Ellner and Nelson G. Hairston, Jr
doi:10.1038/nature04526
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Ecology: Mechanisms for consumer diversity (Reply) pE2
William A. Nelson, Edward McCauley and Frederick J. Wrona
doi:10.1038/nature04527
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Top of pageArticles
Wnt–Ryk signalling mediates medial–lateral retinotectal topographic mapping p31
Adam M. Schmitt, Jun Shi, Alex M. Wolf, Chin-Chun Lu, Leslie A. King and Yimin Zou
doi:10.1038/nature04334
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Structure of the parainfluenza virus 5 F protein in its metastable, prefusion conformation p38
Hsien-Sheng Yin, Xiaolin Wen, Reay G. Paterson, Robert A. Lamb and Theodore S. Jardetzky
doi:10.1038/nature04322
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Top of pageLetters
Radioactive 26Al from massive stars in the Galaxy p45
Roland Diehl, Hubert Halloin, Karsten Kretschmer, Giselher G. Lichti, Volker Schönfelder, Andrew W. Strong, Andreas von Kienlin, Wei Wang, Pierre Jean, Jürgen Knödlseder, Jean-Pierre Roques, Georg Weidenspointner, Stephane Schanne, Dieter H. Hartmann, Christoph Winkler and Cornelia Wunderer
doi:10.1038/nature04364
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Charon's radius and atmospheric constraints from observations of a stellar occultation p48
A. A. S. Gulbis, J. L. Elliot, M. J. Person, E. R. Adams, B. A. Babcock, M. Emilio, J. W. Gangestad, S. D. Kern, E. A. Kramer, D. J. Osip, J. M. Pasachoff, S. P. Souza and T. Tuvikene
doi:10.1038/nature04276
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Charon's size and an upper limit on its atmosphere from a stellar occultation p52
B. Sicardy, A. Bellucci, E. Gendron, F. Lacombe, S. Lacour, J. Lecacheux, E. Lellouch, S. Renner, S. Pau, F. Roques, T. Widemann, F. Colas, F. Vachier, R. Vieira Martins, N. Ageorges, O. Hainaut, O. Marco, W. Beisker, E. Hummel, C. Feinstein, H. Levato, A. Maury, E. Frappa, B. Gaillard, M. Lavayssière, M. Di Sora, F. Mallia, G. Masi, R. Behrend, F. Carrier, O. Mousis, P. Rousselot, A. Alvarez-Candal, D. Lazzaro, C. Veiga, A. H. Andrei, M. Assafin, D. N. da Silva Neto, C. Jacques, E. Pimentel, D. Weaver, J.-F. Lecampion, F. Doncel, T. Momiyama and G. Tancredi
doi:10.1038/nature04351
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Structural diversity in binary nanoparticle superlattices p55
Elena V. Shevchenko, Dmitri V. Talapin, Nicholas A. Kotov, Stephen O'Brien and Christopher B. Murray
doi:10.1038/nature04414
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Abrupt reversal in ocean overturning during the Palaeocene/Eocene warm period p60
Flavia Nunes and Richard D. Norris
doi:10.1038/nature04386
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Three-dimensional brittle shear fracturing by tensile crack interaction p64
David Healy, Richard R. Jones and Robert E. Holdsworth
doi:10.1038/nature04346
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Phosphonate utilization by the globally important marine diazotroph Trichodesmium p68
S. T. Dyhrman, P. D. Chappell, S. T. Haley, J. W. Moffett, E. D. Orchard, J. B. Waterbury and E. A. Webb
doi:10.1038/nature04203
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Computer optimization of a minimal biped model discovers walking and running p72
Manoj Srinivasan and Andy Ruina
doi:10.1038/nature04113
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Complex social behaviour derived from maternal reproductive traits p76
Gro V. Amdam, Angela Csondes, M. Kim Fondrk and Robert E. Page, Jr
doi:10.1038/nature04340
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Rapid developmental switch in the mechanisms driving early cortical columnar networks p79
Erwan Dupont, Ileana L. Hanganu, Werner Kilb, Silke Hirsch and Heiko J. Luhmann
doi:10.1038/nature04264
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Generation of a functional mammary gland from a single stem cell p84
Mark Shackleton, François Vaillant, Kaylene J. Simpson, John Stingl, Gordon K. Smyth, Marie-Liesse Asselin-Labat, Li Wu, Geoffrey J. Lindeman and Jane E. Visvader
doi:10.1038/nature04372
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An siRNA-based microbicide protects mice from lethal herpes simplex virus 2 infection p89
Deborah Palliser, Dipanjan Chowdhury, Qing-Yin Wang, Sandra J. Lee, Roderick T. Bronson, David M. Knipe and Judy Lieberman
doi:10.1038/nature04263
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Potentiation of neuroblastoma metastasis by loss of caspase-8 p95
Dwayne G. Stupack, Tal Teitz, Matthew D. Potter, David Mikolon, Peter J. Houghton, Vincent J. Kidd, Jill M. Lahti and David A. Cheresh
doi:10.1038/nature04323
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Mechanochemical analysis of DNA gyrase using rotor bead tracking p100
Jeff Gore, Zev Bryant, Michael D. Stone, Marcelo Nöllmann, Nicholas R. Cozzarelli and Carlos Bustamante
doi:10.1038/nature04319
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RNA translocation and unwinding mechanism of HCV NS3 helicase and its coordination by ATP p105
Sophie Dumont, Wei Cheng, Victor Serebrov, Rudolf K. Beran, Ignacio Tinoco, Jr, Anna Marie Pyle and Carlos Bustamante
doi:10.1038/nature04331
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Functional waters in intraprotein proton transfer monitored by FTIR difference spectroscopy p109
Florian Garczarek and Klaus Gerwert
doi:10.1038/nature04231
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Top of pageNaturejobs
Prospect
A plan for the future p113
Help on steering your career.
Paul Smaglik
doi:10.1038/nj7072-113a
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Top of pageFutures
Gathering of the clans p116
Get in touch with your past.
Reinaldo José Lopes
doi:10.1038/439116a
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