《Nature》目录要览（2009年7月16日出版）
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《Nature》目录要览（2009年7月16日出版）
封面故事： 两种血吸虫完整基因组序列被确定
The Schistosoma japonicum genome reveals features of host–parasite interplay/The genome of the blood fluke Schistosoma mansoni
两个国际联合课题组在本期Nature上报告了曼氏血吸虫（Schistosoma mansoni）和日
本血吸虫（Schistosoma japonicum）的完整基因组序列。它们是引起血吸虫病（也称
“裂体血吸虫病”）的三种主要病原体中的两种。血吸虫病是一种“被忽视的”热带疾病，影响76个国家的超过2亿人。对新的基因组序列所做分析，为了解这些病原体的分子结构和宿主互动方式以及未来开发该疾病定向干涉疗法的途径提供了线索。这两种血吸虫的基因组是首次被测序的两种扁形虫基因组，所以它们为了解动物演化中的早期事件、尤其是身体模式的确定及组织发育成器官的过程提供了新视角。本期封面上的显微照片（由David Scharf提供，网址：http://www.scharfphoto.com/）所示为一对交配的曼氏血吸虫，大约放大了265倍，较纤细的雌性出现在雄性的下半部分。（Articles pp. 345, 352）
考古学的一个新领域——灵长类考古学（The new archaeology）
Primate archaeology
考古学家在寻找过去人类活动的证据，利用工具、陶器和日常用品的碎片等人工制品来构建当时的生活画面。因被吃掉而出现在碎片中的非人类物种很少被当成家畜；对早期考古工作来说，它们也很少被当成年代证据。本期Nature上的评论文章总结了灵长类动物学与考古学之间已知的交叉，并且进而提出应当建立一个新的学科——灵长类考古学。通过分析过去与现在的灵长类材料记录，我们可从一个新的视角来回答若干重要的问题。灵长类动物使用工具、创建生活地点和构建社会群体。所有这些活动都在考古记录上留下了它们的印记，由此我们可以获得有关人类的认知及工具使用的演化的证据。（Review p. 339）
关于主带天体多样性的另一种解释（Diversity in the asteroid belt）
Contamination of the asteroid belt by primordial trans-Neptunian objects
主小行星带（大致在火星与木星之间）中的大多数天体被假设是由一个原始盘在原位形成的，然而这个带中所含天体之多样令人吃惊，从原始的冰/石混合物到火成岩都有。对这种多样性的传统解释一直是，它代表着与原始行星盘中的最初凝固顺序相关的化学变化，但一系列新的模拟结果却提出了另一种解释。研究人员发现，关于太阳系动态演化的“尼斯”模型（主要是在法国尼斯的蔚蓝海岸天文台建立的一个模型）所要求的巨型行星轨道的猛烈动态演化，会导致将原始的海王星外天体插入到主小行星带的外层区域当中。这些来自太阳系外层的富含有机物的后来者，将会比主带小行星更易受碰撞演化影响，将会是微型陨石的丰富来源，从而可以解释另一个长期未解之谜——微型陨石与宏观（普通）陨石相比的的“原始”组成问题。（Letter p. 364）
冰在北极首次出现的时间（The arrival of Arctic ice）
Evidence for middle Eocene Arctic sea ice from diatoms and ice-rafted debris
北极并非始终存在海冰，而且我们对这一在气候上很敏感的地区的海冰历史的确知之甚少。最近在中始新世海洋沉积物中冰携碎屑的发现，促使人们提出这样的观点：冰是在距今大约4600万年前出现在北极的，但重要的是，要对基于陆地的冰川冰和海冰作为碎屑来源加以区分，因为每种冰有不同气候涵义。现在，对来自ACEX项目的一个海洋沉积芯所做分析，显示了针状硅藻Synedropsis spp.的数量巨大的、保存完好的化石（这种硅藻依靠海冰来生存），其所处位置在北极中部海床之下约260米的地方。结合详细的粒度分析，这一发现表明，海冰在距今约4750万年-4550万年前是冰携碎屑的主导性来源。这些结果将冰在北极的首次出现时间提前了125万年，将海冰硅藻的首次出现时间
提前了1600万年。（Letter p. 376）
关于冰川期气候波动的证据（All glacials are not alike）
Migration of the subtropical front as a modulator of glacial climate
来自几个方面的证据（包括北半球冰层的不同程度）都反映了冰川期波动的严重程度，尽管从南极冰层获取的冰芯表明，冰川状况及气温与大气二氧化碳浓度之间的关系在过去80万年间一直保持不变。现在，来自从西南印度洋获得的一个海洋沉积芯的关于海洋表面温度与海洋生产力之间关系的一项持续时间为80万年的新记录显示，在最冷的冰川期，南非沿海附近的副热带锋向北迁移，改变向“大西洋经向翻转环流”携带热量和盐分的“阿古拉斯海流”的力量。这项工作表明，副热带锋向北迁移的程度可使全球气候与大气二氧化碳浓度部分去耦合（也就是说，使二者之间部分失去关联）。（Letter p. 380; News & Views）
生物多样性中性理论的一种新形式（The road to biodiversity）
Global patterns of speciation and diversity
由Stephen Hubbell在2001年首次论述的生物多样性“中性”理论，通过采用认为每个
个体和每个物种都有相同的行为方式、与物种互动或物种历史无关的简化假设，成功预测了很多人们所观察到的生态多样性模式。本期Nature介绍了中性理论的一种新形式，增添了将有性生殖、突变和扩散等因素考虑在内的内容。这一新模型在很多层面上来模拟现实，与从包括巴拿马灌丛到堪萨斯哺乳动物化石在内的材料获得的真实数据非常相符。这些结果还表明，生物多样性可以在没有具体物理障碍的条件下出现——这种情况与在繁忙车流中所观察到的现象相似：只要有交通，就可能发生交通堵塞，并不需要明显的原因。（Letter p. 384; News & Views）
人类和狒狒FY基因变异的异同（Shared resistance to malaria）
Evolution of a malaria resistance gene in wild primates
在人类中，FY基因（亦称DARC）的变异会造成对间日疟原虫（Plasmodium vivax）之感染是易感还是有抵抗力的差别。FY编码红血细胞表面上的一个趋化因子受体，该受体是这种疟原虫的一个已知的进入点。现在，对肯尼亚安博塞利国家公园中一群黄狒狒所做的一项研究，识别出狒狒FY基因的变异是疟疾类寄生虫“肝囊虫”的易感性的一个关键决定因子。狒狒FY基因的功能性变异形式与在人类中所看到的变异形式并不同源，尽管狒狒和人类FY顺势调控基因区域中的变异模式表明，两个物种之间（的基因变异）在机制上和选择性上都可能具有相似之处。（Letter p. 388; Making the paper p. 305）
雷帕霉素是否可用于延长寿命？（Rapamycin for a longer life?）
Rapamycin fed late in life extends lifespan in genetically heterogeneous mice
抗肿瘤药物雷帕霉素以TOR为作用目标，后者是一种激酶，该激酶是PI3K–AKT–mTOR级联的组成部分，参与调控蛋白转译、细胞生长和自体吞噬。降低TOR功能已知会延长酵母、蠕虫和苍蝇的寿命。现在，在三个不同实验室中重复的实验表明，以可实质性抑制TOR信号作用的一个剂量对雄性和雌性小鼠施用的雷帕霉素，能够将它们的平均和最长寿命延长多达14%。这种寿命延长不但在从270天大开始施用雷帕霉素的小鼠身上观察到，而且还在从他们生命的一个后期阶段、即从600天大开始施用雷帕霉素的小鼠身上观察到。这些发现表明，TOR通道在哺乳动物衰老控制中以及在生命晚期疾病的发病机理中都是一个关键点。（Letter p. 392）
泛素化与寿命之间的关系（Ubiquitination and longevity）
A conserved ubiquitination pathway determines longevity in response to diet restriction
节制饮食会在一系列不同动物物种中延长寿命的事实表明，其中涉及一个保守机制。现在，Carrano等人发现，“E3泛素连接酶”WWP-1在蠕虫中是这种寿命延长所必需的。WWP-1的寿命延长功能是节制饮食所特有的，需要转录因子pha-4，而不是转录因子daf-16，后一种转录因子最为人们所知的是，它能通过降低胰岛素/ IGF1信号作用延长寿命。这一发现将普遍保守的泛素化通道牵涉到了寿命对饮食节制的反应当中。（Letter p. 396）
对海豹肢症病原学的重新思考（A rethink on phocomelia）
A reevaluation of X-irradiation-induced phocomelia and proximodistal limb patterning
先天性疾病海豹肢症（phocomelia）是一种罕见的肢畸形，它在上个世纪60年代作为在怀孕期间使用“反应停”（thalidomide）的一种副作用而更为人们所知。研究人员将发育中的小鸡肢芽暴露于X-射线辐射，从而来模仿海豹肢症；用这种小鸡模型所做的研究工作为早就建立的关于肢发育的渐进带模型提供了重要证据。按照渐进带模型，由“顶端外胚层脊”产生的成纤维细胞生长因子决定细胞命运。涉及分子分析和世系追踪的新的研究工作表明，X-射线辐射诱导的海豹肢症并不是人们过去所认为的一种模式形成缺陷（patterning defect），而是骨骼祖细胞依时丢失所造成的。该发现对海豹肢症病原学的当前模型和渐进带模型的预测结果提出了挑战。（Letter p. 400; Abstractions p. 305）
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NEWS AND VIEWS
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Ageing: A midlife longevity drug? pp331-332
The small molecule rapamycin, already approved for clinical use for various human disorders, has been found to significantly increase lifespan in mice. Is this a step towards an anti-ageing drug for people?
Matt Kaeberlein and Brian K. Kennedy
doi:10.1038/460331a
http://www.nature.com/nature/journal/v460/n7253/full/460331a.html
Atmospheric physics: Cosmic rays, clouds and climate pp332-333
Galactic cosmic rays could influence Earth's cloudiness by creating aerosol particles that prompt cloud formation. That possible effect looks to be smaller than thought, but the story won't end there.
Ken Carslaw
doi:10.1038/460332a
http://www.nature.com/nature/journal/v460/n7253/full/460332a.html
Galaxy formation: Anatomy of elliptical galaxies pp333-334
The family of elliptical galaxies is remarkable for the structural regularity of its members. Inspecting irregularities in this regularity could help in understanding how these galaxies form.
Luca Ciotti
doi:10.1038/460333a
http://www.nature.com/nature/journal/v460/n7253/full/460333a.html
Ecology: Towards a theory of biodiversity pp334-335
Models of ecological communities that incorporate mutation and spatial dispersal can yield results that go some way to explaining observations. A further step is to add sexual reproduction to the mix.
Jayanth R. Banavar and Amos Maritan
doi:10.1038/460334a
http://www.nature.com/nature/journal/v460/n7253/full/460334a.html
Climate change: Beyond the CO2 connection pp335-336
At times in the past, mobile ocean fronts in the subtropics have exercised an influence on the magnitude of climate change by decoupling temperature from levels of carbon dioxide in the atmosphere.
Rainer Zahn
doi:10.1038/460335a
http://www.nature.com/nature/journal/v460/n7253/full/460335a.html
Photonics: Light control at will p337
Microchips that make use of light instead of electrons could outperform their electronic counterparts if light flow can be controlled at will. Photonic crystals are instrumental in achieving such a manoeuvre.
Sajeev John
doi:10.1038/460337a
http://www.nature.com/nature/journal/v460/n7253/full/460337a.html
Obituary: Jean Dausset (1916-2009) p338
'Father' of the human leukocyte antigen system.
Dominique J. Charron
doi:10.1038/460338a
http://www.nature.com/nature/journal/v460/n7253/full/460338a.html
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REVIEW
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Primate archaeology pp339-344
Michael Haslam et al.
doi:10.1038/nature08188
Abstract:
http://www.nature.com/nature/journal/v460/n7253/abs/nature08188.html
Article:
http://www.nature.com/nature/journal/v460/n7253/full/nature08188.html
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ARTICLES
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The Schistosoma japonicum genome reveals features of host-parasite
interplay pp345-351
Schistosoma mansoni and Schistosoma japonicum are the pathogenic agents that cause the tropical disease schistosomiasis. Here, and in an accompanying paper, the genomes of these two flatworms are sequenced and analysed. The results provide insights into the molecular architecture and host interactions of the flatworms, as well as avenues for future development of targeted interventions for schistosomiasis.
doi:10.1038/nature08140
Abstract:
http://www.nature.com/nature/journal/v460/n7253/abs/nature08140.html
Article:
http://www.nature.com/nature/journal/v460/n7253/full/nature08140.html
The genome of the blood fluke Schistosoma mansoni pp352-358
Schistosoma mansoni and Schistosoma japonicum are the pathogenic agents that cause the tropical disease schistosomiasis. Here, and in an accompanying paper, the genomes of these two flatworms are sequenced and analysed. The results provide insights into the molecular architecture and host interactions of the flatworms, as well as avenues for future development of targeted interventions for schistosomiasis.
Matthew Berriman et al.
doi:10.1038/nature08160
Abstract:
http://www.nature.com/nature/journal/v460/n7253/abs/nature08160.html
Article:
http://www.nature.com/nature/journal/v460/n7253/full/nature08160.html
The active form of DNA polymerase V is UmuD[prime]2C-RecA-ATP pp359-363
Escherichia coli DNA polymerase (pol) V is involved in the mutagenic process of limited DNA synthesis across a DNA lesion, but the molecular composition of mutagenically active pol V and the importance of the RecA nucleoprotein filament RecA[ast] have remained unclear. The biochemical role of RecA[ast] is now defined.
Qingfei Jiang et al.
doi:10.1038/nature08178
Abstract:
http://www.nature.com/nature/journal/v460/n7253/abs/nature08178.html
Article:
http://www.nature.com/nature/journal/v460/n7253/full/nature08178.html
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LETTERS
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Contamination of the asteroid belt by primordial trans-Neptunian
objects pp364-366
The main asteroid belt contains a surprising diversity of objects, ranging from primitive ice-rock mixtures to igneous rocks. The standard model used to explain this assumes the violent dynamical evolution of the giant-planet orbits. Here, this evolution is shown to lead to the insertion of primitive trans-Neptunian objects into the outer belt, implying that the observed diversity of the asteroid belt is not a direct reflection of the intrinsic compositional variation of the proto-planetary disk, but rather of dynamical evolution.
Harold F. Levison et al.
doi:10.1038/nature08094
Abstract:
http://www.nature.com/nature/journal/v460/n7253/abs/nature08094.html
Article:
http://www.nature.com/nature/journal/v460/n7253/full/nature08094.html
Manipulation of photons at the surface of three-dimensional photonic crystals pp367-370
Photonic bandgap materials are envisioned to provide the necessary tools for guiding and manipulating photons in optical circuits. So far, basic approaches for photonic control have been based on embedding artificial defects and light emitters inside three-dimensional materials. Here it is demonstrated that three-dimensional photonic crystals possess two-dimensional surface states that can easily be manipulated to control photons, providing an alternative approach.
Kenji Ishizaki and Susumu Noda
doi:10.1038/nature08190
Abstract:
http://www.nature.com/nature/journal/v460/n7253/abs/nature08190.html
Article:
http://www.nature.com/nature/journal/v460/n7253/full/nature08190.html
Photoconductance and inverse photoconductance in films of functionalized metal nanoparticles pp371-375
A photoconductor is a material in which electrical conductivity changes when it is illuminated [mdash] invariably increasing in response to impinging light. However, here it is shown that nanoparticle-based materials can be engineered, through the careful choice of the molecules used to stabilize the nanoparticles, to exhibit negative photoconductance: conductivity in these materials decreases in the presence of light.
Hideyuki Nakanishi et al.
doi:10.1038/nature08131
Abstract:
http://www.nature.com/nature/journal/v460/n7253/abs/nature08131.html
Article:
http://www.nature.com/nature/journal/v460/n7253/full/nature08131.html
Evidence for middle Eocene Arctic sea ice from diatoms and ice-rafted
debris pp376-379
The presence of ice-rafted debris (IRD) in middle Eocene ocean sediments has previously been demonstrated, but it has been unclear whether the source of IRD was land-based glacial ice or sea ice, a distinction with important climate implications. The analysis of a sediment core from the ACEX project now reveals evidence that sea ice was the dominant source for IRD from 47.5 to 45.5 million years ago.
Catherine E. Stickley et al.
doi:10.1038/nature08163
Abstract:
http://www.nature.com/nature/journal/v460/n7253/abs/nature08163.html
Article:
http://www.nature.com/nature/journal/v460/n7253/full/nature08163.html
Migration of the subtropical front as a modulator of glacial climate pp380-383
Ice cores extracted from the Antarctic ice sheet suggest that glacial conditions and the relationship between temperatures and atmospheric carbon dioxide concentrations have been constant over the last 800,000 years, but there is some evidence for a fluctuating severity of glacial periods mediated by previously unidentified mechanisms. Variable migration of the subtropical front is now shown to modulate the severity of glacial periods,
partially decoupling global climate from atmospheric carbon dioxide concentrations.
Edouard Bard and Rosalind E. M. Rickaby
doi:10.1038/nature08189
Abstract:
http://www.nature.com/nature/journal/v460/n7253/abs/nature08189.html
Article:
http://www.nature.com/nature/journal/v460/n7253/full/nature08189.html
Global patterns of speciation and diversity pp384-387
The question of why biological diversity is spread in characteristic patterns is perhaps the biggest problem in ecology. In recent years, the 'neutral theory' of biodiversity has modelled the distribution of species in a very simple way, without reference to species interactions or history. Sexual reproduction, mutation and dispersal are now introduced to the simulation of populations; the resulting predictions correlate well with
real data sets.
M. A. M. de Aguiar et al.
doi:10.1038/nature08168
Abstract:
http://www.nature.com/nature/journal/v460/n7253/abs/nature08168.html
Article:
http://www.nature.com/nature/journal/v460/n7253/full/nature08168.html
Evolution of a malaria resistance gene in wild primates pp388-391
The study of a population of yellow baboons in Amboseli National Park in Kenya reveals the first reported association and functional characterization linking genetic variation and a complex trait [mdash] susceptibility to malaria [mdash] in a natural population of nonhuman primates.
Jenny Tung et al.
doi:10.1038/nature08149
Abstract:
http://www.nature.com/nature/journal/v460/n7253/abs/nature08149.html
Article:
http://www.nature.com/nature/journal/v460/n7253/full/nature08149.html
Rapamycin fed late in life extends lifespan in genetically heterogeneous
mice pp392-395
Although inhibition of the TOR signalling pathway extends lifespan in invertebrates, it was unknown whether mTOR signalling inhibition has similar effects in mammalian species. Here, feeding mice the drug rapamycin [mdash] an inhibitor of the mTOR pathway [mdash] late in life is shown to extend lifespan by 9-14%; currently, the only way to extend lifespan in rodents is by severe dietary restriction.
David E. Harrison et al.
doi:10.1038/nature08221
Abstract:
http://www.nature.com/nature/journal/v460/n7253/abs/nature08221.html
Article:
http://www.nature.com/nature/journal/v460/n7253/full/nature08221.html
A conserved ubiquitination pathway determines longevity in response to diet restriction pp396-399
The fact that dietary restriction increases longevity in diverse species suggests that there is a conserved mechanism for nutrient regulation and prosurvival responses. The E3 ubiquitin ligase WWP-1 and the E2 ubiquitin conjugating enzyme UBC-18 are now shown to be essential for such lifespan extension in the worm Caenorhabditis elegans.
Andrea C. Carrano, Zheng Liu, Andrew Dillin and Tony Hunter
doi:10.1038/nature08130
Abstract:
http://www.nature.com/nature/journal/v460/n7253/abs/nature08130.html
Article:
http://www.nature.com/nature/journal/v460/n7253/full/nature08130.html
A reevaluation of X-irradiation-induced phocomelia and proximodistal limb patterning pp400-404
The condition of phocomelia, a human birth defect in which the long bones are shorter than normal, is mimicked in developing chick limb buds exposed to X-rays. Studies of X-irradiation-induced phocomelia have served as evidence supporting the 'progress zone' model of limb patterning. Here, X-irradiation-induced phocomelia is shown not to be a patterning defect at all; rather, it results from a time-dependent loss of skeletal progenitors.
Jenna L. Galloway, Irene Delgado, Maria A. Ros and Clifford J. Tabin
doi:10.1038/nature08117
Abstract:
http://www.nature.com/nature/journal/v460/n7253/abs/nature08117.html
Article:
http://www.nature.com/nature/journal/v460/n7253/full/nature08117.html
The AP-1 transcription factor Batf controls TH17 differentiation pp405-409
TH17 cells comprise a subset of CD4+ T cells that coordinate the inflammatory response in host defence but are pathogenic in autoimmunity. Here, the AP-1 transcription factor BATF is shown to have a critical role in TH17 cell differentiation, with Batf-/- mice displaying a defect in TH17 differentiation and resistance to experimental autoimmune encephalomyelitis.
Barbara U. Schraml et al.
doi:10.1038/nature08114
Abstract:
http://www.nature.com/nature/journal/v460/n7253/abs/nature08114.html
Article:
http://www.nature.com/nature/journal/v460/n7253/full/nature08114.html
Cohesins form chromosomal cis-interactions at the developmentally regulated IFNG locus pp410-413
As well as its role in sister chromatid cohesion, cohesin is thought to have a role in the control of gene expression. Here, cohesin is shown to form the topological and mechanistic basis for cell-type-specific long-range chromosomal interactions at the developmentally regulated cytokine locus IFNG.
Suzana Hadjur et al.
doi:10.1038/nature08079
Abstract:
http://www.nature.com/nature/journal/v460/n7253/abs/nature08079.html
Article:
http://www.nature.com/nature/journal/v460/n7253/full/nature08079.html
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TECHNOLOGY FEATURES
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Systems biology: Untangling the protein web pp415-418
Researchers have identified thousands of macromolecular interactions within cells. But, as Nathan Blow finds out, joining them up in networks and figuring out how they work still poses a big challenge.
Nathan Blow
doi:10.1038/460415a
http://www.nature.com/nature/journal/v460/n7253/full/460415a.html
Systems biology: Playing by the rules p417
doi:10.1038/460417a
http://www.nature.com/nature/journal/v460/n7253/full/460417a.html
Systems biology: Table of suppliers pp419-420
doi:10.1038/460419a
http://www.nature.com/nature/journal/v460/n7253/full/460419a.html
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FUTURES
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Makeover p428
Off on the wrong track.
James L. Cambias
doi:10.1038/460428a
http://www.nature.com/nature/journal/v460/n7253/full/460428a.html
两个国际联合课题组在本期Nature上报告了曼氏血吸虫（Schistosoma mansoni）和日
本血吸虫（Schistosoma japonicum）的完整基因组序列。它们是引起血吸虫病（也称
“裂体血吸虫病”）的三种主要病原体中的两种。血吸虫病是一种“被忽视的”热带疾病，影响76个国家的超过2亿人。对新的基因组序列所做分析，为了解这些病原体的分子结构和宿主互动方式以及未来开发该疾病定向干涉疗法的途径提供了线索。这两种血吸虫的基因组是首次被测序的两种扁形虫基因组，所以它们为了解动物演化中的早期事件、尤其是身体模式的确定及组织发育成器官的过程提供了新视角。本期封面上的显微照片（由David Scharf提供，网址：http://www.scharfphoto.com/）所示为一对交配的曼氏血吸虫，大约放大了265倍，较纤细的雌性出现在雄性的下半部分。（Articles pp. 345, 352）
考古学的一个新领域——灵长类考古学（The new archaeology）
Primate archaeology
考古学家在寻找过去人类活动的证据，利用工具、陶器和日常用品的碎片等人工制品来构建当时的生活画面。因被吃掉而出现在碎片中的非人类物种很少被当成家畜；对早期考古工作来说，它们也很少被当成年代证据。本期Nature上的评论文章总结了灵长类动物学与考古学之间已知的交叉，并且进而提出应当建立一个新的学科——灵长类考古学。通过分析过去与现在的灵长类材料记录，我们可从一个新的视角来回答若干重要的问题。灵长类动物使用工具、创建生活地点和构建社会群体。所有这些活动都在考古记录上留下了它们的印记，由此我们可以获得有关人类的认知及工具使用的演化的证据。（Review p. 339）
关于主带天体多样性的另一种解释（Diversity in the asteroid belt）
Contamination of the asteroid belt by primordial trans-Neptunian objects
主小行星带（大致在火星与木星之间）中的大多数天体被假设是由一个原始盘在原位形成的，然而这个带中所含天体之多样令人吃惊，从原始的冰/石混合物到火成岩都有。对这种多样性的传统解释一直是，它代表着与原始行星盘中的最初凝固顺序相关的化学变化，但一系列新的模拟结果却提出了另一种解释。研究人员发现，关于太阳系动态演化的“尼斯”模型（主要是在法国尼斯的蔚蓝海岸天文台建立的一个模型）所要求的巨型行星轨道的猛烈动态演化，会导致将原始的海王星外天体插入到主小行星带的外层区域当中。这些来自太阳系外层的富含有机物的后来者，将会比主带小行星更易受碰撞演化影响，将会是微型陨石的丰富来源，从而可以解释另一个长期未解之谜——微型陨石与宏观（普通）陨石相比的的“原始”组成问题。（Letter p. 364）
冰在北极首次出现的时间（The arrival of Arctic ice）
Evidence for middle Eocene Arctic sea ice from diatoms and ice-rafted debris
北极并非始终存在海冰，而且我们对这一在气候上很敏感的地区的海冰历史的确知之甚少。最近在中始新世海洋沉积物中冰携碎屑的发现，促使人们提出这样的观点：冰是在距今大约4600万年前出现在北极的，但重要的是，要对基于陆地的冰川冰和海冰作为碎屑来源加以区分，因为每种冰有不同气候涵义。现在，对来自ACEX项目的一个海洋沉积芯所做分析，显示了针状硅藻Synedropsis spp.的数量巨大的、保存完好的化石（这种硅藻依靠海冰来生存），其所处位置在北极中部海床之下约260米的地方。结合详细的粒度分析，这一发现表明，海冰在距今约4750万年-4550万年前是冰携碎屑的主导性来源。这些结果将冰在北极的首次出现时间提前了125万年，将海冰硅藻的首次出现时间
提前了1600万年。（Letter p. 376）
关于冰川期气候波动的证据（All glacials are not alike）
Migration of the subtropical front as a modulator of glacial climate
来自几个方面的证据（包括北半球冰层的不同程度）都反映了冰川期波动的严重程度，尽管从南极冰层获取的冰芯表明，冰川状况及气温与大气二氧化碳浓度之间的关系在过去80万年间一直保持不变。现在，来自从西南印度洋获得的一个海洋沉积芯的关于海洋表面温度与海洋生产力之间关系的一项持续时间为80万年的新记录显示，在最冷的冰川期，南非沿海附近的副热带锋向北迁移，改变向“大西洋经向翻转环流”携带热量和盐分的“阿古拉斯海流”的力量。这项工作表明，副热带锋向北迁移的程度可使全球气候与大气二氧化碳浓度部分去耦合（也就是说，使二者之间部分失去关联）。（Letter p. 380; News & Views）
生物多样性中性理论的一种新形式（The road to biodiversity）
Global patterns of speciation and diversity
由Stephen Hubbell在2001年首次论述的生物多样性“中性”理论，通过采用认为每个
个体和每个物种都有相同的行为方式、与物种互动或物种历史无关的简化假设，成功预测了很多人们所观察到的生态多样性模式。本期Nature介绍了中性理论的一种新形式，增添了将有性生殖、突变和扩散等因素考虑在内的内容。这一新模型在很多层面上来模拟现实，与从包括巴拿马灌丛到堪萨斯哺乳动物化石在内的材料获得的真实数据非常相符。这些结果还表明，生物多样性可以在没有具体物理障碍的条件下出现——这种情况与在繁忙车流中所观察到的现象相似：只要有交通，就可能发生交通堵塞，并不需要明显的原因。（Letter p. 384; News & Views）
人类和狒狒FY基因变异的异同（Shared resistance to malaria）
Evolution of a malaria resistance gene in wild primates
在人类中，FY基因（亦称DARC）的变异会造成对间日疟原虫（Plasmodium vivax）之感染是易感还是有抵抗力的差别。FY编码红血细胞表面上的一个趋化因子受体，该受体是这种疟原虫的一个已知的进入点。现在，对肯尼亚安博塞利国家公园中一群黄狒狒所做的一项研究，识别出狒狒FY基因的变异是疟疾类寄生虫“肝囊虫”的易感性的一个关键决定因子。狒狒FY基因的功能性变异形式与在人类中所看到的变异形式并不同源，尽管狒狒和人类FY顺势调控基因区域中的变异模式表明，两个物种之间（的基因变异）在机制上和选择性上都可能具有相似之处。（Letter p. 388; Making the paper p. 305）
雷帕霉素是否可用于延长寿命？（Rapamycin for a longer life?）
Rapamycin fed late in life extends lifespan in genetically heterogeneous mice
抗肿瘤药物雷帕霉素以TOR为作用目标，后者是一种激酶，该激酶是PI3K–AKT–mTOR级联的组成部分，参与调控蛋白转译、细胞生长和自体吞噬。降低TOR功能已知会延长酵母、蠕虫和苍蝇的寿命。现在，在三个不同实验室中重复的实验表明，以可实质性抑制TOR信号作用的一个剂量对雄性和雌性小鼠施用的雷帕霉素，能够将它们的平均和最长寿命延长多达14%。这种寿命延长不但在从270天大开始施用雷帕霉素的小鼠身上观察到，而且还在从他们生命的一个后期阶段、即从600天大开始施用雷帕霉素的小鼠身上观察到。这些发现表明，TOR通道在哺乳动物衰老控制中以及在生命晚期疾病的发病机理中都是一个关键点。（Letter p. 392）
泛素化与寿命之间的关系（Ubiquitination and longevity）
A conserved ubiquitination pathway determines longevity in response to diet restriction
节制饮食会在一系列不同动物物种中延长寿命的事实表明，其中涉及一个保守机制。现在，Carrano等人发现，“E3泛素连接酶”WWP-1在蠕虫中是这种寿命延长所必需的。WWP-1的寿命延长功能是节制饮食所特有的，需要转录因子pha-4，而不是转录因子daf-16，后一种转录因子最为人们所知的是，它能通过降低胰岛素/ IGF1信号作用延长寿命。这一发现将普遍保守的泛素化通道牵涉到了寿命对饮食节制的反应当中。（Letter p. 396）
对海豹肢症病原学的重新思考（A rethink on phocomelia）
A reevaluation of X-irradiation-induced phocomelia and proximodistal limb patterning
先天性疾病海豹肢症（phocomelia）是一种罕见的肢畸形，它在上个世纪60年代作为在怀孕期间使用“反应停”（thalidomide）的一种副作用而更为人们所知。研究人员将发育中的小鸡肢芽暴露于X-射线辐射，从而来模仿海豹肢症；用这种小鸡模型所做的研究工作为早就建立的关于肢发育的渐进带模型提供了重要证据。按照渐进带模型，由“顶端外胚层脊”产生的成纤维细胞生长因子决定细胞命运。涉及分子分析和世系追踪的新的研究工作表明，X-射线辐射诱导的海豹肢症并不是人们过去所认为的一种模式形成缺陷（patterning defect），而是骨骼祖细胞依时丢失所造成的。该发现对海豹肢症病原学的当前模型和渐进带模型的预测结果提出了挑战。（Letter p. 400; Abstractions p. 305）
----------------------
NEWS AND VIEWS
----------------------
Ageing: A midlife longevity drug? pp331-332
The small molecule rapamycin, already approved for clinical use for various human disorders, has been found to significantly increase lifespan in mice. Is this a step towards an anti-ageing drug for people?
Matt Kaeberlein and Brian K. Kennedy
doi:10.1038/460331a
http://www.nature.com/nature/journal/v460/n7253/full/460331a.html
Atmospheric physics: Cosmic rays, clouds and climate pp332-333
Galactic cosmic rays could influence Earth's cloudiness by creating aerosol particles that prompt cloud formation. That possible effect looks to be smaller than thought, but the story won't end there.
Ken Carslaw
doi:10.1038/460332a
http://www.nature.com/nature/journal/v460/n7253/full/460332a.html
Galaxy formation: Anatomy of elliptical galaxies pp333-334
The family of elliptical galaxies is remarkable for the structural regularity of its members. Inspecting irregularities in this regularity could help in understanding how these galaxies form.
Luca Ciotti
doi:10.1038/460333a
http://www.nature.com/nature/journal/v460/n7253/full/460333a.html
Ecology: Towards a theory of biodiversity pp334-335
Models of ecological communities that incorporate mutation and spatial dispersal can yield results that go some way to explaining observations. A further step is to add sexual reproduction to the mix.
Jayanth R. Banavar and Amos Maritan
doi:10.1038/460334a
http://www.nature.com/nature/journal/v460/n7253/full/460334a.html
Climate change: Beyond the CO2 connection pp335-336
At times in the past, mobile ocean fronts in the subtropics have exercised an influence on the magnitude of climate change by decoupling temperature from levels of carbon dioxide in the atmosphere.
Rainer Zahn
doi:10.1038/460335a
http://www.nature.com/nature/journal/v460/n7253/full/460335a.html
Photonics: Light control at will p337
Microchips that make use of light instead of electrons could outperform their electronic counterparts if light flow can be controlled at will. Photonic crystals are instrumental in achieving such a manoeuvre.
Sajeev John
doi:10.1038/460337a
http://www.nature.com/nature/journal/v460/n7253/full/460337a.html
Obituary: Jean Dausset (1916-2009) p338
'Father' of the human leukocyte antigen system.
Dominique J. Charron
doi:10.1038/460338a
http://www.nature.com/nature/journal/v460/n7253/full/460338a.html
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REVIEW
----------------------
Primate archaeology pp339-344
Michael Haslam et al.
doi:10.1038/nature08188
Abstract:
http://www.nature.com/nature/journal/v460/n7253/abs/nature08188.html
Article:
http://www.nature.com/nature/journal/v460/n7253/full/nature08188.html
----------------------
ARTICLES
----------------------
The Schistosoma japonicum genome reveals features of host-parasite
interplay pp345-351
Schistosoma mansoni and Schistosoma japonicum are the pathogenic agents that cause the tropical disease schistosomiasis. Here, and in an accompanying paper, the genomes of these two flatworms are sequenced and analysed. The results provide insights into the molecular architecture and host interactions of the flatworms, as well as avenues for future development of targeted interventions for schistosomiasis.
doi:10.1038/nature08140
Abstract:
http://www.nature.com/nature/journal/v460/n7253/abs/nature08140.html
Article:
http://www.nature.com/nature/journal/v460/n7253/full/nature08140.html
The genome of the blood fluke Schistosoma mansoni pp352-358
Schistosoma mansoni and Schistosoma japonicum are the pathogenic agents that cause the tropical disease schistosomiasis. Here, and in an accompanying paper, the genomes of these two flatworms are sequenced and analysed. The results provide insights into the molecular architecture and host interactions of the flatworms, as well as avenues for future development of targeted interventions for schistosomiasis.
Matthew Berriman et al.
doi:10.1038/nature08160
Abstract:
http://www.nature.com/nature/journal/v460/n7253/abs/nature08160.html
Article:
http://www.nature.com/nature/journal/v460/n7253/full/nature08160.html
The active form of DNA polymerase V is UmuD[prime]2C-RecA-ATP pp359-363
Escherichia coli DNA polymerase (pol) V is involved in the mutagenic process of limited DNA synthesis across a DNA lesion, but the molecular composition of mutagenically active pol V and the importance of the RecA nucleoprotein filament RecA[ast] have remained unclear. The biochemical role of RecA[ast] is now defined.
Qingfei Jiang et al.
doi:10.1038/nature08178
Abstract:
http://www.nature.com/nature/journal/v460/n7253/abs/nature08178.html
Article:
http://www.nature.com/nature/journal/v460/n7253/full/nature08178.html
----------------------
LETTERS
----------------------
Contamination of the asteroid belt by primordial trans-Neptunian
objects pp364-366
The main asteroid belt contains a surprising diversity of objects, ranging from primitive ice-rock mixtures to igneous rocks. The standard model used to explain this assumes the violent dynamical evolution of the giant-planet orbits. Here, this evolution is shown to lead to the insertion of primitive trans-Neptunian objects into the outer belt, implying that the observed diversity of the asteroid belt is not a direct reflection of the intrinsic compositional variation of the proto-planetary disk, but rather of dynamical evolution.
Harold F. Levison et al.
doi:10.1038/nature08094
Abstract:
http://www.nature.com/nature/journal/v460/n7253/abs/nature08094.html
Article:
http://www.nature.com/nature/journal/v460/n7253/full/nature08094.html
Manipulation of photons at the surface of three-dimensional photonic crystals pp367-370
Photonic bandgap materials are envisioned to provide the necessary tools for guiding and manipulating photons in optical circuits. So far, basic approaches for photonic control have been based on embedding artificial defects and light emitters inside three-dimensional materials. Here it is demonstrated that three-dimensional photonic crystals possess two-dimensional surface states that can easily be manipulated to control photons, providing an alternative approach.
Kenji Ishizaki and Susumu Noda
doi:10.1038/nature08190
Abstract:
http://www.nature.com/nature/journal/v460/n7253/abs/nature08190.html
Article:
http://www.nature.com/nature/journal/v460/n7253/full/nature08190.html
Photoconductance and inverse photoconductance in films of functionalized metal nanoparticles pp371-375
A photoconductor is a material in which electrical conductivity changes when it is illuminated [mdash] invariably increasing in response to impinging light. However, here it is shown that nanoparticle-based materials can be engineered, through the careful choice of the molecules used to stabilize the nanoparticles, to exhibit negative photoconductance: conductivity in these materials decreases in the presence of light.
Hideyuki Nakanishi et al.
doi:10.1038/nature08131
Abstract:
http://www.nature.com/nature/journal/v460/n7253/abs/nature08131.html
Article:
http://www.nature.com/nature/journal/v460/n7253/full/nature08131.html
Evidence for middle Eocene Arctic sea ice from diatoms and ice-rafted
debris pp376-379
The presence of ice-rafted debris (IRD) in middle Eocene ocean sediments has previously been demonstrated, but it has been unclear whether the source of IRD was land-based glacial ice or sea ice, a distinction with important climate implications. The analysis of a sediment core from the ACEX project now reveals evidence that sea ice was the dominant source for IRD from 47.5 to 45.5 million years ago.
Catherine E. Stickley et al.
doi:10.1038/nature08163
Abstract:
http://www.nature.com/nature/journal/v460/n7253/abs/nature08163.html
Article:
http://www.nature.com/nature/journal/v460/n7253/full/nature08163.html
Migration of the subtropical front as a modulator of glacial climate pp380-383
Ice cores extracted from the Antarctic ice sheet suggest that glacial conditions and the relationship between temperatures and atmospheric carbon dioxide concentrations have been constant over the last 800,000 years, but there is some evidence for a fluctuating severity of glacial periods mediated by previously unidentified mechanisms. Variable migration of the subtropical front is now shown to modulate the severity of glacial periods,
partially decoupling global climate from atmospheric carbon dioxide concentrations.
Edouard Bard and Rosalind E. M. Rickaby
doi:10.1038/nature08189
Abstract:
http://www.nature.com/nature/journal/v460/n7253/abs/nature08189.html
Article:
http://www.nature.com/nature/journal/v460/n7253/full/nature08189.html
Global patterns of speciation and diversity pp384-387
The question of why biological diversity is spread in characteristic patterns is perhaps the biggest problem in ecology. In recent years, the 'neutral theory' of biodiversity has modelled the distribution of species in a very simple way, without reference to species interactions or history. Sexual reproduction, mutation and dispersal are now introduced to the simulation of populations; the resulting predictions correlate well with
real data sets.
M. A. M. de Aguiar et al.
doi:10.1038/nature08168
Abstract:
http://www.nature.com/nature/journal/v460/n7253/abs/nature08168.html
Article:
http://www.nature.com/nature/journal/v460/n7253/full/nature08168.html
Evolution of a malaria resistance gene in wild primates pp388-391
The study of a population of yellow baboons in Amboseli National Park in Kenya reveals the first reported association and functional characterization linking genetic variation and a complex trait [mdash] susceptibility to malaria [mdash] in a natural population of nonhuman primates.
Jenny Tung et al.
doi:10.1038/nature08149
Abstract:
http://www.nature.com/nature/journal/v460/n7253/abs/nature08149.html
Article:
http://www.nature.com/nature/journal/v460/n7253/full/nature08149.html
Rapamycin fed late in life extends lifespan in genetically heterogeneous
mice pp392-395
Although inhibition of the TOR signalling pathway extends lifespan in invertebrates, it was unknown whether mTOR signalling inhibition has similar effects in mammalian species. Here, feeding mice the drug rapamycin [mdash] an inhibitor of the mTOR pathway [mdash] late in life is shown to extend lifespan by 9-14%; currently, the only way to extend lifespan in rodents is by severe dietary restriction.
David E. Harrison et al.
doi:10.1038/nature08221
Abstract:
http://www.nature.com/nature/journal/v460/n7253/abs/nature08221.html
Article:
http://www.nature.com/nature/journal/v460/n7253/full/nature08221.html
A conserved ubiquitination pathway determines longevity in response to diet restriction pp396-399
The fact that dietary restriction increases longevity in diverse species suggests that there is a conserved mechanism for nutrient regulation and prosurvival responses. The E3 ubiquitin ligase WWP-1 and the E2 ubiquitin conjugating enzyme UBC-18 are now shown to be essential for such lifespan extension in the worm Caenorhabditis elegans.
Andrea C. Carrano, Zheng Liu, Andrew Dillin and Tony Hunter
doi:10.1038/nature08130
Abstract:
http://www.nature.com/nature/journal/v460/n7253/abs/nature08130.html
Article:
http://www.nature.com/nature/journal/v460/n7253/full/nature08130.html
A reevaluation of X-irradiation-induced phocomelia and proximodistal limb patterning pp400-404
The condition of phocomelia, a human birth defect in which the long bones are shorter than normal, is mimicked in developing chick limb buds exposed to X-rays. Studies of X-irradiation-induced phocomelia have served as evidence supporting the 'progress zone' model of limb patterning. Here, X-irradiation-induced phocomelia is shown not to be a patterning defect at all; rather, it results from a time-dependent loss of skeletal progenitors.
Jenna L. Galloway, Irene Delgado, Maria A. Ros and Clifford J. Tabin
doi:10.1038/nature08117
Abstract:
http://www.nature.com/nature/journal/v460/n7253/abs/nature08117.html
Article:
http://www.nature.com/nature/journal/v460/n7253/full/nature08117.html
The AP-1 transcription factor Batf controls TH17 differentiation pp405-409
TH17 cells comprise a subset of CD4+ T cells that coordinate the inflammatory response in host defence but are pathogenic in autoimmunity. Here, the AP-1 transcription factor BATF is shown to have a critical role in TH17 cell differentiation, with Batf-/- mice displaying a defect in TH17 differentiation and resistance to experimental autoimmune encephalomyelitis.
Barbara U. Schraml et al.
doi:10.1038/nature08114
Abstract:
http://www.nature.com/nature/journal/v460/n7253/abs/nature08114.html
Article:
http://www.nature.com/nature/journal/v460/n7253/full/nature08114.html
Cohesins form chromosomal cis-interactions at the developmentally regulated IFNG locus pp410-413
As well as its role in sister chromatid cohesion, cohesin is thought to have a role in the control of gene expression. Here, cohesin is shown to form the topological and mechanistic basis for cell-type-specific long-range chromosomal interactions at the developmentally regulated cytokine locus IFNG.
Suzana Hadjur et al.
doi:10.1038/nature08079
Abstract:
http://www.nature.com/nature/journal/v460/n7253/abs/nature08079.html
Article:
http://www.nature.com/nature/journal/v460/n7253/full/nature08079.html
----------------------
TECHNOLOGY FEATURES
----------------------
Systems biology: Untangling the protein web pp415-418
Researchers have identified thousands of macromolecular interactions within cells. But, as Nathan Blow finds out, joining them up in networks and figuring out how they work still poses a big challenge.
Nathan Blow
doi:10.1038/460415a
http://www.nature.com/nature/journal/v460/n7253/full/460415a.html
Systems biology: Playing by the rules p417
doi:10.1038/460417a
http://www.nature.com/nature/journal/v460/n7253/full/460417a.html
Systems biology: Table of suppliers pp419-420
doi:10.1038/460419a
http://www.nature.com/nature/journal/v460/n7253/full/460419a.html
----------------------
FUTURES
----------------------
Makeover p428
Off on the wrong track.
James L. Cambias
doi:10.1038/460428a
http://www.nature.com/nature/journal/v460/n7253/full/460428a.html
环境科学之家（http://www.eschina.org.cn/）
| 《Nature》目录要览 — 2011-04-28出版 |
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