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ningkeqing木虫 (正式写手)
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Nature Contents 26 October 2006 (pp883-1030)
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[自然要览] （选自英国Nature杂志，2006年10月26日出版） 封面故事：蜜蜂基因组完成测序 Insights into social insects from the genome of the honeybee Apis mellifera “蜜蜂基因组测序联合课题组”本周发表了蜜蜂Apis mellifera的完整基因组序 列。蜜蜂通过授粉对全球生态具有重要影响，它们也是研究社会行为的一种关键 模型。该基因组所含主管先天免疫、表皮形成和味觉受体的基因数量少于其他昆 虫，但所含气味受体多于其他昆虫，并且含有用于花蜜和花粉利用的新颖基因。 种群遗传学知识有助于我们了解非洲化蜜蜂是否是通过杂交或迁移从“新世界” 向外扩散的。在配发的一篇News and Views文章中，E. O. Wilson对“将蜜蜂提 升到一个高级的社会组织状态”的深远的生物学变化是怎样反映在新测序的基因 组中的进行了分析。封面所示为一株犬齿赤莲上的一只蜜蜂。（Carrol W. Perkins/photolibrary.com）（Article p. 931; News and Views p. 919） 一种当“甩手掌柜”的蠕虫（Symbiosis: doing without） Symbiosis insights through metagenomic analysis of a microbial consortium Olavius algarvensis是一种海洋寡毛纲蠕虫，存在于地中海厄尔巴岛沿海浅水 沙子中。它们的解剖特征是引人注目的，因为它们不但没有嘴、胃和肠，而且没 有肾管（nephridia），即肾脏一样的器官。消化系统的省略出现在其他动物 中，但这种动物是惟一省略了自己的排泄系统以适应共生方式的寄主。现在，生 活在这些蠕虫皮肤下面的共生细菌群落的基因组成已被确定。多源基因组分析揭 示了如此多的重要寄主任务何以被外包给了共生体。（Letter p. 950; News and Views） 燧石能够反映海水温度变化的史（Sands of time） A palaeotemperature curve for the Precambrian oceans based on silicon isotopes in cherts 燧石是含有石英微晶的致密的硅质岩石，是地球上保存最完好的海洋沉积物之 一，其形成涵盖的时间段从距今35亿年前的太古代早期到现在。新的数据表明， 燧石的硅同位素组成随地质年龄有系统性变化，并且与氧同位素组成具有相关 性。这意味着，燧石的同位素组成很可能记录了它们的形成温度。利用关于硅循 环数值模型从这些数据获得的同位素曲线，提供了前寒武纪海水温度变化的一个 独特记录，其变化从距今35亿年前到距今8亿年前在70摄氏度至20摄氏度之间。 （Letter p. 969, News and Views） 水合作用对地幔物质电导性的影响（Rising damp?） Hydrous olivine unable to account for conductivity anomaly at the top of the asthenosphere / The effect of water on the electrical conductivity of olivine 地幔的性质（如粘度和熔化温度）受含水量严重影响。然而，确定地幔含水量仍 然富有挑战性。曾有人提出，橄榄石的水合作用是岩流圈（地壳和上层地幔下面 的可变形层）高电导性的原因，但水对这些物质的影响（通过氢的结合而产生） 尚未在实验室中确定。现在，两个小组报告了关于氢对橄榄石电导性影响的实验 结果。他们都发现，少量氢能急剧增加电导性，但它们关于这种水合作用是否能 够解释所观察到的地幔电导性的结论却不一致。显然，需要进行更多工作来确定 这种偏差背后的因素。（Letters pp. 973, 977; News and Views） 南非发现迄今最古老七鳃鳗化石（Out of the shadows） A lamprey from the Devonian period of South Africa 七鳃鳗和八目鳗是现存惟一无颚脊椎动物，在关于现存有颚脊椎动物的比较研究 中普遍被用作“代理祖先”。直到不久前，科学家对七鳃鳗的演化历史还知之甚 少，因为惟一已知化石是来自距今约3亿年前的石炭纪时期的谜一样的样本。后 来，今年早些时候，Nature发表了来自中国石炭纪地层的一个精细化石标本，它 看起来非常接近现代形式。现在，又有了一个来自南非泥盆纪地层的保存完好的 化石，距今约3.6亿年，是已知最古老的七鳃鳗。它看起来与现代七鳃鳗稍有不 同，但在重要方面都是一样的，而与同样来自泥盆纪的各种不同的、现已灭绝的 披甲鱼类有所不同。（Letter p. 981） 决定四肢形状的遗传因素（Tetrapods toe the line） Regulatory constraints in the evolution of the tetrapod limb anterior –posterior polarity 四足动物四肢前后极性，即可解释为什么你的大拇指和小拇指是不同的等现象的 不对称性， 是由Sonic hedgehog (Shh)基因在胚胎肢芽（limb bud）后部的表 达早就确定了的。Shh表达反过来由HoxA 和 HoxD类群中的基因控制的。 Tarchini等人发现，Shh基因由Hox类群中更靠后的成员控制，也就是说，由那些 其表达因它们的同线性转录激发而被排除在最靠前肢芽之外的基因控制。换句话 说，四肢形状的形成，是躯干中Hox基因表达的同线性的一个副作用，这便为关 于演化过程用可供利用的原材料来做什么的理论施加了一个遗传学上的约束条 件。（Letter p. 985） 物种损失对生态系统功能的影响（Species loss and productivity） Effects of biodiversity on the functioning of trophic groups and ecosystems 关于物种灭绝是否会改变群落生产力和生态系统功能的问题，是一个争议非常大 的问题。上个世纪90年代所做的研究工作表明，物种损失可降低群落的生产力， 降低它们捕捉和消耗有限资源方面的效率。对这些研究结果的理解是有争议的， 后来的研究工作产生了若干反例，这些反例使关于生物多样性效应的普遍性受到 质疑。现在，Cardinale等人报告了对关于物种多样性和生态功能的实验研究所 进行的一次“多源分析”（meta-analysis）结果。他们的结论是，物种损失的 确影响生态功能，但影响的程度取决于具体损失的是哪些物种。（Letter p. 989） 角膜中的抗血管生成分子（Bloodless evolution） Corneal avascularity is due to soluble VEGF receptor-1 角膜是身体上少数没有血管在其中流通的组织之一。这个没有血管的“岛屿”经 常被用来试验癌症、关节炎、动脉硬化、糖尿病和由病理性血管生成驱动的其他 疾病的抗血管生成疗法。该组织没有血管是引人注目的，这是由于其周围组织都 有高度发达的血管，而更为引人注目的是因为角膜现在被发现含有大量强效抗血 管生成分子VEGF-A (血管内皮生长因子)。该发现又导致了一个对药物设计而很 重要的发现：作为一种可溶性VEGFR-1的一种VEGF-A 阱也存在于角膜中，角膜中 没有血管正是由该物质这一个因素造成的。有趣的是，已知含血管角膜的少数动 物（海牛、突变小鼠和一些有Pax6突变的先天性无虹膜症患者）都缺少角膜可溶 性VEGFR-1。（Letter p. 993） 可用于风湿性关节炎药物研究的动物模型（This year’s model） Chronic polyarthritis caused by mammalian DNA that escapes from degradation in macrophages 用于治疗风湿性关节炎的药物的开发 一直没有一种好的动物模型的帮助。现 在，一种新开发的突变小鼠模型有可能帮助填补这个空白。这种小鼠缺少 DNaseII基因，是被第二个突变从那个突变的致命影响中拯救过来的，这第二个 突变允许干扰素的组成性生成。这种小鼠患了慢性多发性关节炎，与人类的风湿 性关节炎类似，原因是在细胞程序死亡和定向红血球生成过程中DNA降解失败 了。这是出乎意料的：对各种不同小鼠组织所做的分析表明，携带未降解DNA的 巨噬细胞会被激活，产生TNF（肿瘤坏死因子），导致多发性关节炎的发展。有 趣的是，TNF与风湿性关节炎的发病有关，抗TNF疗法有时被用来治疗该疾病。 （Letter p. 998） 基因放大的新机制 （Making more of genes） Amplification of histone genes by circular chromosome formation in Saccharomyces cerevisiae 基因放大的一种以前不知道的机制，已在酿酒酵母(Saccharomyces cerevisiae) 中被发现，它涉及基因组中包含组蛋白基因、一个端粒和DNA复制起源的一个区 域两侧的转位子之间的重组。转位子序列物理上交联、重组为一个稳定的环形染 色体，含有被放大的基因。这一特定的重组事件在组蛋白H2A 和 H2B水平下降的 细胞中得到加强。类似机制人类可能也有，因为人类基因组45%由转位子组成。 （Letter p. 1003） |
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ningkeqing
木虫 (正式写手)
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---------------------- NEWS AND VIEWS ---------------------- Genomics: How to make a social insect The profound biological changes that lofted the honeybee to an advanced state of social organization are reflected in its newly sequenced genome. The species can now be studied all the way from molecule to colony. Edward O. Wilson 10.1038/443919a http://www.nature.com/nature/journal/v443/n7114/full/443919a.html Palaeoceanography: In hot water There has long been scepticism about the geochemical evidence that the ancient ocean was markedly warm. A fresh approach bolsters the case for an ocean that, in the distant past, was indeed quite hot. Christina L. De La Rocha 10.1038/443920a http://www.nature.com/nature/journal/v443/n7114/full/443920a.html Palaeontology: Modern look for ancient lamprey It was once thought that lampreys evolved from armoured jawless vertebrates. But a recently discovered lamprey fossil dates from the twilight age of their supposed ancestors, and looks surprisingly modern. Philippe Janvier 10.1038/443921a http://www.nature.com/nature/journal/v443/n7114/full/443921a.html 50 & 100 years ago 10.1038/443923a http://www.nature.com/nature/journal/v443/n7114/full/443923a.html Electromagnetism: Like a speeding watch A rotation in light's electric-field vector can alter the light's frequency. This rotational equivalent of the Doppler effect has proved surprisingly elusive, but has now been spotted in the laboratory. Miles Padgett 10.1038/443924a http://www.nature.com/nature/journal/v443/n7114/full/443924a.html Genomics: Blueprints for partnerships Gutless marine worms harness the resources of a team of bacteria in lieu of a digestive or excretory system. A genome-sequence analysis now defines the roles of the microbes. David A. Stahl and Seana K. Davidson 10.1038/nature05208 http://www.nature.com/nature/jou ... ll/nature05208.html Geophysics: Protons lead the charge Is the anomalously high electrical conductivity seen in part of Earth's mantle caused by protons derived from hydrous defects in the mineral olivine? Two groups investigate this possibility -- and draw different conclusions. Greg Hirth 10.1038/443927a http://www.nature.com/nature/journal/v443/n7114/full/443927a.html Developmental biology: Red-eye redirected Barbara Marte 10.1038/443928a http://www.nature.com/nature/journal/v443/n7114/full/443928a.html CORRESPONDENCE Correction 10.1038/443928b http://www.nature.com/nature/journal/v443/n7114/full/443928b.html ---------------------- BRIEF COMMUNICATIONS ---------------------- Palaeontology: Skull morphology of giant terror birds These monstrous birds were probably more agile and less portly than previously thought. Luis M. Chiappe and Sara Bertelli 10.1038/443929a http://www.nature.com/nature/journal/v443/n7114/full/443929a.html BRIEF COMMUNICATIONS ARISING Evolutionary biology: Sympatric plant speciation in islands? Tod F. Stuessy 10.1038/nature05216 Abstract: http://www.nature.com/nature/jou ... bs/nature05216.html Article: http://www.nature.com/nature/jou ... ll/nature05216.html Evolutionary biology: Sympatric plant speciation in islands? (Reply) Vincent Savolainen et al. 10.1038/nature05217 Abstract: http://www.nature.com/nature/jou ... bs/nature05217.html Article: http://www.nature.com/nature/jou ... ll/nature05217.html ---------------------- ARTICLES ---------------------- Insights into social insects from the genome of the honeybee Apis mellifera The Honeybee Genome Sequencing Consortium 10.1038/nature05260 Abstract: http://www.nature.com/nature/jou ... bs/nature05260.html Article: http://www.nature.com/nature/jou ... ll/nature05260.html Symbiosis insights through metagenomic analysis of a microbial consortium Tanja Woyke et al. 10.1038/nature05192 Abstract: http://www.nature.com/nature/jou ... bs/nature05192.html Article: http://www.nature.com/nature/jou ... ll/nature05192.html Complete crystallographic analysis of the dynamics of CCA sequence addition A series of crystallographic 'snapshots' of tRNA maturase reveals the molecular changes in the enzyme that holds it in place on the tRNA, accommodating incoming CTP and ATP nucleotides, and allowing repositioning of the active site after each of the first two CMP residues are added. Kozo Tomita, Ryuichiro Ishitani, Shuya Fukai and Osamu Nureki 10.1038/nature05204 Abstract: http://www.nature.com/nature/jou ... bs/nature05204.html Article: http://www.nature.com/nature/jou ... ll/nature05204.html ---------------------- LETTERS ---------------------- Evidence for superfluidity of ultracold fermions in an optical lattice Evidence for superfluidity of ultracold fermionic atom pairs in an optical lattice details that such systems are highly controllable, making them attractive models for studying analogous problems such as high-temperature superconductivity. J. K. Chin et al. 10.1038/nature05224 Abstract: http://www.nature.com/nature/jou ... bs/nature05224.html Article: http://www.nature.com/nature/jou ... ll/nature05224.html Exploration of molecular dynamics during transient sorption of fluids in mesoporous materials A combination of nuclear magnetic resonance measurements and computer simulations is used to probe directly the dynamics of molecular uptake, both inside and out of the hysteresis regime, and identifies marked differences in the dynamics that are directly correlated with the existence or otherwise of hysteresis. Rustem Valiullin et al. 10.1038/nature05183 Abstract: http://www.nature.com/nature/jou ... bs/nature05183.html Article: http://www.nature.com/nature/jou ... ll/nature05183.html A palaeotemperature curve for the Precambrian oceans based on silicon isotopes in cherts Francois Robert and Marc Chaussidon 10.1038/nature05239 Abstract: http://www.nature.com/nature/jou ... bs/nature05239.html Article: http://www.nature.com/nature/jou ... ll/nature05239.html Hydrous olivine unable to account for conductivity anomaly at the top of the asthenosphere Takashi Yoshino, Takuya Matsuzaki, Shigeru Yamashita and Tomoo Katsura 10.1038/nature05223 Abstract: http://www.nature.com/nature/jou ... bs/nature05223.html Article: http://www.nature.com/nature/jou ... ll/nature05223.html The effect of water on the electrical conductivity of olivine Duojun Wang, Mainak Mookherjee, Yousheng Xu and Shun-ichiro Karato 10.1038/nature05256 Abstract: http://www.nature.com/nature/jou ... bs/nature05256.html Article: http://www.nature.com/nature/jou ... ll/nature05256.html A lamprey from the Devonian period of South Africa Robert W. Gess, Michael I. Coates and Bruce S. Rubidge 10.1038/nature05150 Abstract: http://www.nature.com/nature/jou ... bs/nature05150.html Article: http://www.nature.com/nature/jou ... ll/nature05150.html Regulatory constraints in the evolution of the tetrapod limb anterior-posterior polarity Basile Tarchini, Denis Duboule and Marie Kmita 10.1038/nature05247 Abstract: http://www.nature.com/nature/jou ... bs/nature05247.html Article: http://www.nature.com/nature/jou ... ll/nature05247.html Effects of biodiversity on the functioning of trophic groups and ecosystems A meta-analysis of experimental studies addresses the relationship between species diversity and ecological functioning, and concludes that reduction in species loss does affect ecological functioning, but that the magnitude of these effects depends on which species are actually lost. Bradley J. Cardinale et al. 10.1038/nature05202 Abstract: http://www.nature.com/nature/jou ... bs/nature05202.html Article: http://www.nature.com/nature/jou ... ll/nature05202.html Corneal avascularity is due to soluble VEGF receptor-1 Balamurali K. Ambati et al. 10.1038/nature05249 Abstract: http://www.nature.com/nature/jou ... bs/nature05249.html Article: http://www.nature.com/nature/jou ... ll/nature05249.html Chronic polyarthritis caused by mammalian DNA that escapes from degradation in macrophages Kohki Kawane et al. 10.1038/nature05245 Abstract: http://www.nature.com/nature/jou ... bs/nature05245.html Article: http://www.nature.com/nature/jou ... ll/nature05245.html Amplification of histone genes by circular chromosome formation in Saccharomyces cerevisiae Diana E. Libuda and Fred Winston 10.1038/nature05205 Abstract: http://www.nature.com/nature/jou ... bs/nature05205.html Article: http://www.nature.com/nature/jou ... ll/nature05205.html Distinct catalytic and non-catalytic roles of ARGONAUTE4 in RNA-directed DNA methylation Yijun Qi et al. 10.1038/nature05198 Abstract: http://www.nature.com/nature/jou ... bs/nature05198.html Article: http://www.nature.com/nature/jou ... ll/nature05198.html CORRIGENDA Corrigendum: The DNA sequence and biological annotation of human chromosome 1 S. G. Gregory et al. 10.1038/nature05152 http://www.nature.com/nature/jou ... ll/nature05152.html RETRACTION Retraction: Origin of the obliquities of the giant planets in mutual interactions in the early Solar System Adrian Brunini 10.1038/nature05298 http://www.nature.com/nature/jou ... ll/nature05298.html CORRIGENDA Corrigendum: Complete photo-fragmentation of the deuterium molecule T. Weber et al. 10.1038/nature05296 Abstract: http://www.nature.com/nature/jou ... bs/nature05296.html Article: http://www.nature.com/nature/jou ... ll/nature05296.html ***** |
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