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Nature Contents 18 May 2006 (Vol. 441 pp.255-384)
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[自然要览] （选自英国Nature杂志，2006年5月18日出版） 封面故事：微观世界中合作与欺骗的演化 Evolution of an obligate social cheater to a superior cooperator 生活在土中的社会性细菌Myxococcus xanthus形成大量成群的细胞，这些细胞通过分泌 能杀死和降解其猎物的代谢物的方式捕食其他微生物，产生大量细胞外营养物。饥饿促 使这些细胞集结成大约有10万个成员的群体（见本期封面），它们通过交换细胞间信号 来构建子实体（fruiting bodies），并分异成抗压力的孢子。这为研究演化生物学中 一个长期悬疑的问题提供了一个难得的模型，这个问题就是合作与欺骗策略的演化。在 子实体发育上有缺陷的一些M. xanthus基因型“欺骗”嵌合体群体中没有缺陷的基因 型。一个欺骗者所发生的单一的自发突变，能恢复有效的合作发育，使其在适应性上相 对于两个祖先基因型都具有优越性，这种优越性包括，它可以不受其祖先欺骗者的剥削 和利用。（Article p. 310; News and Views）封面图片：Jürgen Berger & Supriya Kadam, MPI Tübingen 太阳系外第一个在“适宜居住”区域内的行星（It’s another world） An extrasolar planetary system with three Neptune-mass planets 随着寻找太阳系外行星所用技术的发展，越来越多的太阳系外行星已被发现（超过170 个），所发现的行星也越来越小。近年来，研究人员已经探测到7个被称为“热海王 星”或“超级地球”的行星。这些行星的质量比地球大5-20倍，在绕与太阳相似的恒星 的很近的轨道上运行（轨道周期为2-15天）。现在，研究人员发现了第一个多星体系， 由三个“海王星”质量的行星组成，轨道周期分别为8.67天、31.6天和197天（在“适 宜居住”的区域内）。它们都绕附近一颗编号为HD 69830的恒星运行。理论计算表明， 两个靠内的行星都主要由石质物质组成。靠外的一个行星很可能在一个石质或冰质的核 心周围包裹着一层明显的气体。它是第一个在一颗与太阳类似的恒星的“适宜居住”区 域内探测到的“海王星”质量的行星。（Article p. 305; News and Views） 人类染色体全部测序完成（FINAL CHAPTER) The DNA sequence and biological annotation of human chromosome 1 Nature杂志关于已完成的人类基因组序列的系列论文到本期就结束了，本期发表的是人 类1号染色体的分析结果。该染色体尽管是最后一个发表的，但并不是最不重要的一 个：它是人类染色体中最大的一个，基因密集，共有3,141个基因和991个假基因。“自 然出版集团”将于2006年6月1日出版22个常染色体、加上X和Y两个性染色体的已完成序 列的合集，同时配发“新闻和评论”文章。（Article p. 315） 所有时间尺度上的气温变化都有联系（The long view of temperature） Links between annual, Milankovitch and continuum temperature variability 科学家对影响年际气温变化的因素已经相当了解了，但对在十年至千年时间尺度上对地 球气温变化进行总体控制的因素却并不是很了解。除了少数几个气候变化模式外，这些 因素通常被描述为随机过程。Peter Huybers 和William Curry在这个方面往前更进了 一步，他们发现，气温变化在所有时间尺度上是联系在一起的。在地表气温与年度和具 有中间时间尺度的米兰柯维奇(Milankovitch)周期（23,000年至41,000年）之间有一个 简单的“幂次法则”关系，这种关系是由太阳辐射决定的。该发现提供了一个了解地球 气温变化、提高年际和更长时间尺度气候变化预测性的框架。（Letter p. 329） 被子植物“活化石”的一种新型胚囊（Angiosperm evolution: Unfinished business） Embryological evidence for developmental lability during early angiosperm evolution 达尔文称开花植物（也叫被子植物）的起源“令人讨厌的神秘”。如今，这个谜仍然远 没有完全解开，但随着一种新型胚囊（雌性生殖结构）在一种名叫Amborella trichopoda的常绿灌木（这种灌木现在仅见于新喀里多尼亚岛上）上的发现，人们在这 个方面也可以说取得了一些进展。Amborella是最古老被子植物分支惟一现存的代表， 是一种真正的“活化石”。 它的胚囊为了解开花植物早期演化中的一个实验期提供了 线索，可能代表着裸子植物和被子植物之间的一个关键中间形式。（Letter p. 337） 铜可能是海洋中一种潜在重要养分（Trading in iron for copper） Copper-containing plastocyanin used for electron transport by an oceanic diatom 硅藻占海洋生产力的40%，受海洋中铁盐缺乏的严重限制。这种重要营养物质的短缺也 许可解释一个令人吃惊的发现：海洋硅藻Thalassiosira oceanica利用一种含铜“质体 蓝素”（plastocyanin）运输电子，而所有其他含叶绿素-c的物种（包括沿海硅藻）都 是利用含铁的细胞色素c6。这些金属蛋白的利用，与海洋中有可以利用的铜和铁的条件 是一致的，而这一新的发现表明，铜是开放海洋中一种潜在的重要营养成分。（Letter p. 341） 一种引人注目的共生机制（Symbiosis can be catching） Horizontal endosymbiont transmission in hydrothermal vent tubeworms Riftia pachyptila（巨型无内脏管虫，见于热液喷孔附近）的成虫如果没有为其提供 营养的共生细菌的话，可能就不会存在。然而这些管虫的幼虫没有共生体，对每一代的 管虫，细菌都必须重新进驻。曾有人提出，这种管虫是通过摄取的办法获得细菌的，但 一项新的研究却提出了一种非常不同的、独特的细菌进驻过程。细菌是通过感染管虫的 皮肤、并穿过其皮肤迁移的方式到达它们的共生环境的，这个过程伴随着寄主组织的大 量死亡。物种间这种引人注目的互动，是一种新颖的共生启动机制，与致病感染类似。 （Letter p. 345） 高浓度甜味剂引起苦味的原因（Bitter sweeteners） A TAS1R receptor-based explanation of sweet 'water-taste' 有趣的是，糖精钠和乙酰磺胺酸钾等人造甜味剂如果用量过大时不但不甜，还可能有苦 味。然后如果用水漱口，嘴里就会有甜味。这些现象为了解TAS1R味觉受体的作用提供 了新线索。除了引起“甜水”后觉外，高浓度糖精还能掩盖同时所尝的其他甜味剂的效 应。在分子层次上所出现的是一个由两个结合点构成的体系。糖精和乙酰磺胺酸钾结合 到一个高亲和力的结合点上时，会产生甜味；而在高浓度时，它们则结合到第二个低亲 和力的抑制性点上。当甜味抑制成分被水洗掉时，甜味受体重新激活，甜味的感觉又回 来了。甜味抑制成分在食品工业上被用来抵消不想要的高甜度，这种高甜度是由于在某 些低脂肪产品中用甜碳水化合物取代脂肪而产生的：甜水味可以用来指示甜味抑制成分 的活性。（Letter p. 354） 一种具有广谱活性的新型强力抗生素（A new line in antibiotics） Platensimycin is a selective FabF inhibitor with potent antibiotic properties 致病细菌对抗生素的抗药性在全世界的发展引起人们严重关切：今天用在一线的抗生素 有一天可能会失效。所以，一组新的具有用作抗生素的巨大潜力的化合物的发现，将会 引起人们极大兴趣。Platensimycin是一组新的天然产物中的第一个成员，它能通过抑 制FabF/FabB蛋白选择性杀死细菌，这是一个在临床应用中的任何药品都没有采用的机 制。它是一种对革兰氏阳性细菌具有广谱活性的强力抗生素，包括临床上有关的抗药性 细菌，如对Methicillin具有抗药性的金黄葡萄球菌(MRSA)和对万古霉素具有抗药性的 肠球菌（VRE）。（Letter p. 358; News and Views） “角蛋白-17”在细胞生长中的作用（Cell growth: Repaired for action） A keratin cytoskeletal protein regulates protein synthesis and epithelial cell growth 受控生长是细胞的一个重要性质，被用来促进组织再生：在基本“家政工作”方面低速 再生；在组织修复方面快速再生。现在，研究发现，“角蛋白-17”（上皮细胞中一种 结构蛋白）在需要迅速细胞生长的条件下参与蛋白合成机器的激发。角蛋白是被称为 “角蛋白中间细丝”的细胞骨架纤维聚合物的构造单元，帮助细胞抵抗机械损伤。这一 新发现揭示了一个出人意料的机制，细胞骨架利用该机制调控蛋白合成和生长。它对了 解身体怎样进行组织重造具有广泛意义。（Letter p. 362; News and Views） 能解释“西格玛F”转录因子作用的数学模型（Development: Genes speak volumes） The mechanism of cell differentiation in Bacillus subtilis 发育生物学中一个关键问题是，含有相同基因组的细胞何以有不同基因表达模式。这个 问题归结为名为“芽胞杆菌”（Bacillus subtilis）的细菌的基本生物学问题。在孢 子形成的早期，由于营养压力，一个“芽胞杆菌”细胞内部分裂成两个腔室，它们注定 要走不同发育路径。一个被称为“西格玛F”的转录因子在该过程中是一个关键因素， 它和控制它的调控因子已经受到了广泛的研究。然而，关于差异性基因激发如何开始的 详细情况仍然不明了。现在，研究人员开发出了一个数学模型，它能在试管试验中重复 实验结果，并能解释“西格玛F”的作用。该模型发现，两个细胞类型之间体积比的变 化，是细胞命运的主要触发因素，该变化导致它们当中其中一个中的一个关键磷酸酶 （SpoIIE）的活性发生变化。（Letter p. 371） |
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ningkeqing
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---------------------- NEWS AND VIEWS ---------------------- Sociobiology: The Phoenix effect A spore-forming bacterium can escape from social collapse and extinction with a single mutation that has a dramatic effect. Here is evidence that a cooperative system can recover from the very brink of destruction. Kevin R. Foster http://www.nature.com/nature/journal/v441/n7091/full/441291a.html Extrasolar planets: A neptunian triplet Three planets of Neptune mass have been discovered orbiting a Sun-like star known to have an asteroid belt. Exquisite measurements suggest that the search for habitable planets might be easier than assumed. David Charbonneau http://www.nature.com/nature/journal/v441/n7091/full/441292a.html Microbiology: Antibiotic stops ‘ping-pong’ match As bacteria become resistant to existing drugs, there is a need for antibiotics with new modes of action. Such a compound has been found, and it works by binding to an intermediate in the catalytic cycle of its target. Eric D. Brown http://www.nature.com/nature/journal/v441/n7091/full/441293a.html Solid-state physics: When is a metal not a metal? When it's an insulator, of course. Materials that should in theory conduct electricity — but don't — are well known, but the anomalous behaviour of one material has caused particular head-scratching. Steven C. Erwin http://www.nature.com/nature/journal/v441/n7091/full/441295a.html Cell biology: Skin care by keratins Keratin proteins perform several functions in skin cells, including those of providing mechanical support and protection against injury. But it seems they also have a more active part to play in healing wounds. M. Bishr Omary and Nam-On Ku http://www.nature.com/nature/journal/v441/n7091/full/441296a.html Plasma physics: Cool vibes Ultracold plasmas blur the classical boundaries between the different states of matter. Newly observed electron-density waves could become useful probes of how electrons behave in this exotic regime. Thomas C. Killian http://www.nature.com/nature/journal/v441/n7091/full/441297a.html Evolution: Experiments in botany Henry Gee http://www.nature.com/nature/journal/v441/n7091/full/441298a.html Device physics: A bug-beating diode A diode that emits light at a shorter wavelength than ever before shows huge — albeit destructive — technological promise. But further work is needed to ensure that this promise is fulfilled. Asif Khan http://www.nature.com/nature/journal/v441/n7091/full/441299a.html ---------------------- NEWS AND VIEWS FEATURE ---------------------- Microbial sciences: The superficial life of microbes The social activities and organization of bacteria are crucial to their ecological success. But it is only in recent years that we have begun to study these secret societies. Roberto Kolter and E. Peter Greenberg http://www.nature.com/nature/journal/v441/n7091/full/441300a.html ---------------------- BRIEF COMMUNICATIONS ---------------------- Language evolution: Semantic combinations in primate calls Putty-nosed monkeys rely on two basic calling sounds to construct a message of utmost urgency. Kate Arnold and Klaus Zuberbühler Abstract: http://www.nature.com/nature/journal/v441/n7091/abs/441303a.html Article: http://www.nature.com/nature/journal/v441/n7091/full/441303a.html BRIEF COMMUNICATIONS ARISING Immunology: Toll-like receptors and antibody responses D. Nemazee, A. Gavin, K. Hoebe and B. Beutler Abstract: http://www.nature.com/nature/jou ... bs/nature04875.html Article: http://www.nature.com/nature/jou ... ll/nature04875.html Immunology: Toll-like receptors and antibody responses (Reply) C. Pasare and R. Medzhitov Abstract: http://www.nature.com/nature/jou ... bs/nature04876.html Article: http://www.nature.com/nature/jou ... ll/nature04876.html ---------------------- ARTICLES ---------------------- An extrasolar planetary system with three Neptune-mass planets Simulations show that the system of three Neptune-mass planets is in a dynamically stable configuration, with theoretical calculations favouring a mainly rocky composition for both inner planets, but a significant gaseous envelope surrounding a rocky/icy core for the outer planet. Christophe Lovis, Michel Mayor, Francesco Pepe, Yann Alibert, Willy Benz, Fran?ois Bouchy, Alexandre C. M. Correia, Jacques Laskar, Christoph Mordasini, Didier Queloz, Nuno C. Santos, Stéphane Udry, Jean-Loup Bertaux and Jean-Pierre Sivan Abstract: http://www.nature.com/nature/jou ... bs/nature04828.html Article: http://www.nature.com/nature/jou ... ll/nature04828.html Evolution of an obligate social cheater to a superior cooperator Francesca Fiegna, Yuen-Tsu N. Yu, Supriya V. Kadam and Gregory J. Velicer Abstract: http://www.nature.com/nature/jou ... bs/nature04677.html Article: http://www.nature.com/nature/jou ... ll/nature04677.html The DNA sequence and biological annotation of human chromosome[thinsp]1 S. G. Gregory et al. Abstract: http://www.nature.com/nature/jou ... bs/nature04727.html Article: http://www.nature.com/nature/jou ... ll/nature04727.html ---------------------- LETTERS ---------------------- Suppression of dwarf galaxy formation by cosmic reionization J. Stuart B. Wyithe and Abraham Loeb Abstract: http://www.nature.com/nature/jou ... bs/nature04748.html Article: http://www.nature.com/nature/jou ... ll/nature04748.html An aluminium nitride light-emitting diode with a wavelength of 210 nanometres The development of a compact, solid-state light-emitting diode (LED) that emits at 210 nanometres -- the shortest wavelength yet achieved for any type of LED -- represents an important step towards achieving exciton-related light-emitting devices and replacing inefficient gas light sources with solid-state light sources. Yoshitaka Taniyasu, Makoto Kasu and Toshiki Makimoto Abstract: http://www.nature.com/nature/jou ... bs/nature04760.html Article: http://www.nature.com/nature/jou ... ll/nature04760.html Links between annual, Milankovitch and continuum temperature variability Reconstructions and observations of Earth's surface temperature are used to examine variability at scales from annual to Milankovitch (23 and 41 kyr) cycles and find that temperature variability is linked at all timescales in response to deterministic solar forcing. Peter Huybers and William Curry Abstract: http://www.nature.com/nature/jou ... bs/nature04745.html Article: http://www.nature.com/nature/jou ... ll/nature04745.html Seismic detection of folded, subducted lithosphere at the core–mantle boundary Seismic tomography of the D' region beneath the Caribbean reveals a 100-km vertical step in an otherwise flat D' shear velocity discontinuity and localized low velocities at the edge of the slab material, which may involve upwellings caused by the slab laterally displacing a thin hot thermal boundary layer. Alexander R. Hutko, Thorne Lay, Edward J. Garnero and Justin Revenaugh Abstract: http://www.nature.com/nature/jou ... bs/nature04757.html Article: http://www.nature.com/nature/jou ... ll/nature04757.html Embryological evidence for developmental lability during early angiosperm evolution Discovery of a new type of embryo sac in the plant Amborella -- the sole living representative of the most ancient angiosperm lineage, and a true /`living fossil/' -- sheds light on a period of experimentation in the early evolution and origin of flowering plants. William E. Friedman Abstract: http://www.nature.com/nature/jou ... bs/nature04690.html Article: http://www.nature.com/nature/jou ... ll/nature04690.html Copper-containing plastocyanin used for electron transport by an oceanic diatom Graham Peers and Neil M. Price Abstract: http://www.nature.com/nature/jou ... bs/nature04630.html Article: http://www.nature.com/nature/jou ... ll/nature04630.html Horizontal endosymbiont transmission in hydrothermal vent tubeworms Hydrothermal tubeworms are nutritionally dependent on their bacterial symbionts, but the larvae are symbiont-free and must be colonized anew each generation -- the bacteria reach their symbiotic niche through infection of and migration through the skin, which is accompanied by massive apoptosis of host tissue. Andrea D. Nussbaumer, Charles R. Fisher and Monika Bright Abstract: http://www.nature.com/nature/jou ... bs/nature04793.html Article: http://www.nature.com/nature/jou ... ll/nature04793.html Polycomb complexes repress developmental regulators in murine embryonic stem cells Laurie A. Boyer, Kathrin Plath, Julia Zeitlinger, Tobias Brambrink, Lea A. Medeiros, Tong Ihn Lee, Stuart S. Levine, Marius Wernig, Adriana Tajonar, Mridula K. Ray, George W. Bell, Arie P. Otte, Miguel Vidal, David K. Gifford, Richard A. Young and Rudolf Jaenisch Abstract: http://www.nature.com/nature/jou ... bs/nature04733.html Article: http://www.nature.com/nature/jou ... ll/nature04733.html A TAS1R receptor-based explanation of sweet ‘water-taste’ Veronica Galindo-Cuspinera, Marcel Winnig, Bernd Bufe, Wolfgang Meyerhof and Paul A. S. Breslin Abstract: http://www.nature.com/nature/jou ... bs/nature04765.html Article: http://www.nature.com/nature/jou ... ll/nature04765.html Platensimycin is a selective FabF inhibitor with potent antibiotic properties A new class of antibiotics that targets bacterial lipid biosynthesis is isolated from Streptomyces platensis, and demonstrates potent in vitro and in vivo activity against Gram- positive bacteria -- including methicillin-resistant Staphylococcus species. Jun Wang et al. Abstract: http://www.nature.com/nature/jou ... bs/nature04784.html Article: http://www.nature.com/nature/jou ... ll/nature04784.html A keratin cytoskeletal protein regulates protein synthesis and epithelial cell growth A cytoskeletal protein found inside specific epithelial cells, keratin 17, participates in the activation of protein synthesis under conditions calling for rapid cell growth, such as wound repair. Seyun Kim, Pauline Wong and Pierre A. Coulombe Abstract: http://www.nature.com/nature/jou ... bs/nature04659.html Article: http://www.nature.com/nature/jou ... ll/nature04659.html Critical role for the p110α phosphoinositide-3-OH kinase in growth and metabolic regulation Lazaros C. Foukas, Marc Claret, Wayne Pearce, Klaus Okkenhaug, Stephen Meek, Emma Peskett, Sara Sancho, Andrew J. H. Smith, Dominic J. Withers and Bart Vanhaesebroeck Abstract: http://www.nature.com/nature/jou ... bs/nature04694.html Article: http://www.nature.com/nature/jou ... ll/nature04694.html The mechanism of cell differentiation in Bacillus subtilis Dagmar Iber, Joanna Clarkson, Michael D. Yudkin and Iain D. Campbell Abstract: http://www.nature.com/nature/jou ... bs/nature04666.html Article: http://www.nature.com/nature/jou ... ll/nature04666.html Cleavage of pre-tRNAs by the splicing endonuclease requires a composite active site Cleavage of the 5' site of introns requires an unusual composite active site with the catalytic residues coming from Sen2, and the cation [pi] sandwich coming from Sen34. Christopher R. Trotta, Sergey V. Paushkin, Meenal Patel, Hong Li and Stuart W. Peltz Abstract: http://www.nature.com/nature/jou ... bs/nature04741.html Article: http://www.nature.com/nature/jou ... ll/nature04741.html |
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4楼2006-05-20 20:50:48
