| 查看: 247 | 回复: 1 | |||
| 当前主题已经存档。 | |||
ningkeqing木虫 (正式写手)
|
[交流]
Nature Contents 13 April 2006 (Vol. 440 pp.715-844)
|
||
|
[自然要览] （选自英国Nature杂志，2006年4月13日出版） 封面故事：味觉差异的奥秘 Independent evolution of bitter-taste sensitivity in humans and chimpanzees 是否能够尝到苦味是是否能够发现食物中毒素的关键。苯硫脲（PTC）是一种不同寻常 的化学物质，其特殊性在于它要么味道非常苦，要么几乎没有味道，这主要取决于一个 人的遗传情况。在1939年发表在Nature杂志上的一篇经典论文中，R. A. Foster、E. B. Ford 和J. S. Huxley指出，黑猩猩对PTC也有不同的敏感度，这被认为是反映了人 类与黑猩猩之间共有的一个古老的遗传多态性，是由自然选择维持下来的。现在，由于 主管人类PTC敏感度的TAS2R38位点已经被识别出来，Wooding等人便对人类与黑猩猩在 这个问题上的相似性重新做了比较。TAS2R38也与黑猩猩的PTC敏感度有关，但令人吃惊 的是，造成这一多态性的突变在两个物种身上是不同的。在原始人类的演化过程中， “无味觉”等位基因似乎至少独立演化过两次。由D. J. Cox拍摄的封面照片是2003年3 月在美国田纳西州查塔努加动物园里拍摄的，照片上的黑猩猩正在尽可能多地收集水 果。（Letter p. 930; www.nature.com/podcast） 能在陆地上捕食的鳗鲶鱼（A fish out of water） Evolution: A catfish that can strike its prey on land 上期Nature杂志封面文章介绍的是一个改变世界的事件，即有四肢的脊椎动物从有鳍的 鱼类的发展和演化过程。这一事件又是如何导致脊椎动物征服陆地的呢？关于这个问 题，研究人员现在找到了一个意想不到的线索，那就是在热带非洲泥质沼泽中发现的鳗 鲶鱼。这种动物在陆地上吃草和捕获猎物的能力非常强。进食时，这种动物能将其脑袋 向下弯，该本领似乎是其适应性的秘密之所在。（Brief Communication p. 881） 比“露西”更早的“南方古猿”（Australopithecus before Lucy） Asa Issie, Aramis and the origin of Australopithecus 人类被普遍认为是由“南方古猿”这个属的动物演化来的，但这个属的起源却笼罩在一 层迷雾中。在埃塞俄比亚一处名为Middle Awash的研究区域一个以前未曾取样分析的时 间段中新发现的化石，为这个研究课题增添了重要信息。它们是“南方古猿湖畔种” （Australopithecus anamensis）已知最早的成员，是在肯尼亚Turkana盆地之外发现 的第一批此类化石。这些动物生活在一个林地环境中，它们的化石反映了“南方古猿湖 畔种”会是怎样由更原始的地猿（Ardipithecus）演化来的，并且“南方古猿湖畔种” 还可能是被俗称为“露西”的“南方古猿阿法种”（Australopithecus afarensis）的 祖先。（Article p. 883; www.nature.com/podcast） 关于“织女星”的新老问题（Falling standards） Vega is a rapidly rotating star “织女星”是北半球可以看到的第二颗最亮的恒星，被天文学家用作一个确定其他恒星 亮度的标准。对该恒星在其整个光谱范围内的光强度我们都已精确了解，其亮度也与能 量输出联系了起来。但是，根据这种比较得出的结论一直存在问题，于是就有人提出， “织女星”从极地方向看是一个失真的、迅速转动的恒星。现在，Peterson等人报告 说，“织女星”的确在迅速转动，从地球上来看也几乎是极地朝向我们的。这个观点解 决了早先的一些问题，但又为“织女星”的年龄增添了不确定性，并且提出这样一个可 能性：该恒星的尘埃环有可能比我们所想的古老得多。（Letter p. 896; News and Views） 量子世界中的“牛顿摆”（Cradle to wave） A quantum Newton's cradle “牛顿摆”是一种流行的教具和益智玩具，它反映了一维体系中动量的守恒。现在，研 究人员在一种一维玻色气体中也生成了这样一个量子世界中的“牛顿摆”。在量子“牛 顿摆”中，由超冷铷原子构成的一维阵列互相碰撞数千次，彼此之间又反弹开来或通过 彼此进行传播，而不会有明显的阻尼。该体系有可能在力传感装置和原子干涉仪中找到 用途。（Letter p. 900; News and Views） 一种新型有机光源（The white light of technology） Management of singlet and triplet excitons for efficient white organic light-emitting devices 随着节约能源受到各国政府的高度重视，寻找经济光源的工作便成为一个热门研究领 域。本期Nature报告的一项进展可能是这一领域所迈出的重要一步。该研究工作为制造 颜色稳定的有机发光装置确定了一个新的架构，这类装置能够产生适用于固体发光的白 光。该技术的新颖之处是使用了荧光和磷光掺杂材料，它们可以优化电荷的俘获，内部 量子效率有可能达到100%。这种类型的技术有可能使有机发光装置（OLED）的发光效率 远远高于白炽发光装置。即便现在还处在发展过程的早期，这种新光源在类似亮度下的 发光效率也要比今天的白炽光源高出近75%。（Letter p. 908） 来自地幔的岩石（Rock of ages） Deep origin and hot melting of an Archaean orogenic peridotite massif in Norway 进入地球深处是不容易的。但现在，科学家发现，在挪威西部一个名叫奥特洛伊的地 方，来自年轻地球深处的一大块地幔可供进行研究。那里的达到公里尺度的裸露岩石来 自深度超过400公里的地球深层，该现象仅由地表构造是无法解释的。这些地幔岩石一 定是分阶段露出地面的。首先，在由深度至少在350公里至120公里之间的地方进行上涌 的过程中，地幔岩石发生熔化；然后，经过10亿年左右的停顿之后，最后的一次构造跳 跃将其带到了地面。（Letter p. 913） 甲烷的厌氧氧化反应（Ridding the world of methane） A microbial consortium couples anaerobic methane oxidation to denitrification 虽然存在很多猜测，但尚未发现能够用硝酸盐作为惟一电子受体来在厌氧条件下氧化甲 烷的微生物。现在，研究人员已经在实验室里的一个微生物群落中演示了这一反应，该 微生物群落有两个成员，一个是一种生长缓慢的细菌，该类型的细菌以前没有培养过； 另一个是一种古生物。两种生物典型的核酸标记物都存在于全世界的淡水样品中，说明 该反应在生物甲烷和氮循环中是一个重要环节。该反应还有可能被用来抑制与集约型农 业生产有关的甲烷生成量的增加。（Letter p. 918; News and Views） 土壤氮对未来气候的影响（Nitrogen sets the scene） Nitrogen limitation constrains sustainability of ecosystem response to CO2 大气中CO2浓度的未来趋势以及未来气候的发展趋势，都将部分取决于陆地生态系统积 累来自人类活动的CO2排放的程度。对草地进行的一项为期6年的野外研究发现，因CO2 浓度升高所造成的生物质的增加在周围环境中氮供应的影响下随着时间的推移将下降， 但不是在氮富集的影响下，说明不同土壤中氮含量的自然变化和氮沉降速度的变化都有 可能影响植物生物质积累对CO2浓度升高所产生的响应。氮在很多被管理的和未管理的 土壤中都是一个限制因素，所以土壤氮可能是影响全球对CO2浓度升高的响应情况的一 个重要限制因素。（Letter p. 922） 一种奇异的母爱形式（Yummy mummy） Parental investment by skin feeding in a caecilian amphibian 研究人员在一群神秘的热带脊椎动物中发现了一种特别不寻常的母爱形式。在卵生的两 栖动物Boulengerula taitanus的种群中，幼子用专门的牙齿来剥掉并吃下其母亲变性 的皮肤外层，从而确保在自己的生命中有一个良好的开端。这种奇异的行为可以被看作 是演化上的一个环节，它为相关胎生两栖动物在输卵管内壁上哺育胎儿铺平了道路。该 论文“补充信息”中的影片看起来的确是血淋淋的。（Letter p. 926） 用STED显微镜观测联会囊（Single-synapse microscopy） STED microscopy reveals that synaptotagmin remains clustered after synaptic vesicle exocytosis STED（受激发射损耗）显微镜是一种新型光学显微镜技术，它能克服限制传统荧光显微 镜分辨率的衍射障碍。这种显微镜能够观测联会囊大小（40纳米）的结构。现在STED显 微镜首次被用来分辨哺乳动物中枢神经系统中单次联会中的各个联会囊。对神经传输物 质的释放至关重要的联合囊循环已被深入研究了30多年，但仍有一个大问题没有回答： 它们的构成成分是在胞质膜上扩散，还是仍然聚集在一起？STED显微镜的观测结果显 示，至少一个主要成分，即synaptotagmin-1，在胞外分泌之后仍然聚集在一起，是被 整体循环的。（Letter p. 935） 一种利用转基因酵母生产青蒿素衍生物的方法（Battling malaria） Production of the antimalarial drug precursor artemisinic acid in engineered yeast 具有抗药性的疟疾寄生虫广泛存在，因此由疟疾所导致的死亡人数近年来明显增加。从 中药材青蒿中分离出的青蒿素，是惟一能够高效杀死疟疾寄生虫的药物。由于需求量 大，只能从植物中来提取的青蒿素已经供不应求。现在，Ro等人报告说，他们利用基因 工程方法培育出了携带一个青蒿基因的酵母，这种酵母能产生该药物的前体物质青蒿素 酸。青蒿素酸可通过化学方法进行改造，变成活性青蒿素衍生物。关于这一方法的效率 还需要做进一步研究，但它却有可能缓解该药物的短缺，降低生产成本。（Letter p. 940; www.nature.com/podcast） |
回复此楼» 猜你喜欢
机械工程264学硕求调剂
已经有3人回复
-
264求调剂
已经有9人回复
-
求调剂
已经有6人回复
-
22408 266求调剂
已经有7人回复
-
求调剂
已经有14人回复
-
273求调剂
已经有43人回复
-
307求调剂
已经有13人回复
-
327求调剂
已经有7人回复
-
338求调剂
已经有6人回复
-
326分，一志愿沪9，求生物学调剂
已经有3人回复
» 本主题相关商家推荐: (我也要在这里推广)
ningkeqing
木虫 (正式写手)
- 应助: 0 (幼儿园)
- 金币: 1925.4
- 帖子: 826
- 在线: 16小时
- 虫号: 71943
- 注册: 2005-06-02
- 性别: GG
- 专业: 无机非金属基复合材料
|
---------------------- NEWS AND VIEWS ---------------------- Astrophysics: A whirling dervish Vega is a fundamental reference star for astronomers. But it seems that our perceptions of it have been misconceived -- rather than spinning slowly, the star is a rapid rotator seen pole-on. Richard Gray http://www.nature.com/nature/journal/v440/n7086/full/440873a.html Ageing: Chromatin unbound Sir2 proteins slow ageing in yeast by locking chromatin -- the DNA and proteins in chromosomes -- into a stable, silent state. Inactivating a Sir2 family protein in mice causes premature ageing and genome instability. Jan Vijg and Yousin Suh http://www.nature.com/nature/journal/v440/n7086/full/440874a.html Conservation biology: Roads and genetic connectivity The Ventura Freeway slices through wildlife habitat near Los Angeles. A case study shows how large highways such as this can seriously impede genetic exchange in large vertebrates. Jared L. Strasburg http://www.nature.com/nature/journal/v440/n7086/full/440875a.html Chemistry: A nose for sarin Andrew Mitchinson http://www.nature.com/nature/journal/v440/n7086/full/440876a.html Quantum physics: Equilibrium on hold Startlingly, two atomic clouds confined to one dimension can be made to pass through each other repeatedly without ever coming to rest. Such non-equilibrium phenomena are fundamental, but experimentally elusive. Henk T. C. Stoof http://www.nature.com/nature/journal/v440/n7086/full/440877a.html Biogeochemistry: Methane and microbes Microorganisms can carry out a wonderful range of chemical transformations. The anaerobic oxidation of methane seemed not to be among them. But it is -- both with sulphate, and now it turns out, with nitrate. Rudolf K. Thauer and Seigo Shima http://www.nature.com/nature/journal/v440/n7086/full/440878a.html Biological imaging: The diffraction barrier broken The conventional optical limitations of fluorescence microscopy have been defied, to achieve nanoscale resolution of individual vesicle organelles at the junctions of neuronal cells. Garth J. Simpson http://www.nature.com/nature/journal/v440/n7086/full/440879a.html Behavioural ecology: Grasshoppers don't play possum When about to be eaten by frogs, certain grasshoppers assume a static, unwieldy pose that means they cannot be swallowed. Similar behaviours, interpreted as feigning death, may also be open to alternative explanations. Graeme Ruxton http://www.nature.com/nature/journal/v440/n7086/full/440880a.html ---------------------- BRIEF COMMUNICATIONS ---------------------- Evolution: A catfish that can strike its prey on land This denizen of tropical swamps may shed light on how ancient fish were able to survive out of water. Sam Van Wassenbergh, Anthony Herrel, Dominique Adriaens, Frank Huysentruyt, Stijn Devaere and Peter Aerts Abstract: http://www.nature.com/nature/journal/v440/n7086/abs/440881a.html Article: http://www.nature.com/nature/journal/v440/n7086/full/440881a.html BRIEF COMMUNICATIONS ARISING Taxonomy: Sus bucculentus revisited Judith H. Robins, Howard A. Ross, Melinda S. Allen and Elizabeth Matisoo-Smith Abstract: http://www.nature.com/nature/jou ... bs/nature04770.html Article: http://www.nature.com/nature/jou ... ll/nature04770.html ---------------------- ARTICLES ---------------------- Asa Issie, Aramis and the origin of Australopithecus Newly recovered Ethiopian fossils of Australopithecus anamensis show how Australopithecus might have evolved from the earlier and more primitive genus Ardipithecus, and might have been a harbinger of Australopithecus afarensis, better known as /`Lucy/'. Tim D. White, Giday WoldeGabriel, Berhane Asfaw, Stan Ambrose, Yonas Beyene, Raymond L. Bernor, Jean-Renaud Boisserie, Brian Currie, Henry Gilbert, Yohannes Haile-Selassie, William K. Hart, Leslea J. Hlusko, F. Clark Howell, Reiko T. Kono, Thomas Lehmann, Antoine Louchart, C. Owen Lovejoy, Paul R. Renne, Haruo Saegusa, Elisabeth S. Vrba, Hank Wesselman and Gen Suwa Abstract: http://www.nature.com/nature/jou ... bs/nature04629.html Article: http://www.nature.com/nature/jou ... ll/nature04629.html Chemokines enhance immunity by guiding naive CD8+ T cells to sites of CD4+ T cell-dendritic cell interaction Dendritic cells that interact in a pathogen-specific manner with CD4+ T cells produce chemical signals that actively attract naive CD8+ T cells. Interference with these guidance signals promoting CD8+ T-cell association with this select dendritic cell subpopulation prevents the development of optimal immunological memory responses. Flora Castellino, Alex Y. Huang, Gr?(c)goire Altan-Bonnet, Sabine Stoll, Clemens Scheinecker and Ronald N. Germain Abstract: http://www.nature.com/nature/jou ... bs/nature04651.html Article: http://www.nature.com/nature/jou ... ll/nature04651.html ---------------------- LETTERS ---------------------- Vega is a rapidly rotating star Vega, the second brightest star in the northern hemisphere, is shown to be rapidly rotating, but seen almost pole-on. This finding adds uncertainty to Vega's age and raises the possibility that its debris disk could be substantially older than previously thought. D. M. Peterson, C. A. Hummel, T. A. Pauls, J. T. Armstrong, J. A. Benson, G. C. Gilbreath, R. B. Hindsley, D. J. Hutter, K. J. Johnston, D. Mozurkewich and H. R. Schmitt Abstract: http://www.nature.com/nature/jou ... bs/nature04661.html Article: http://www.nature.com/nature/jou ... ll/nature04661.html A quantum Newton's cradle A report on a form of quantum 'Newton's cradle', in which one-dimensional arrays of ultracold rubidium atoms undergo thousands of collisions without significant damping. The experiment sheds light on the fundamental dynamics of such systems, and may find applications in force sensing and atom interferometry. Toshiya Kinoshita, Trevor Wenger and David S. Weiss Abstract: http://www.nature.com/nature/jou ... bs/nature04693.html Article: http://www.nature.com/nature/jou ... ll/nature04693.html Parametric oscillation in vertical triple microcavities C. Diederichs, J. Tignon, G. Dasbach, C. Ciuti, A. Lemaitre, J. Bloch, Ph. Roussignol and C. Delalande Abstract: http://www.nature.com/nature/jou ... bs/nature04602.html Article: http://www.nature.com/nature/jou ... ll/nature04602.html Management of singlet and triplet excitons for efficient white organic light-emitting devices Through careful management of the bound electron-hole pairs responsible for light emission, efficiencies can be achieved that should challenge those of the incandescent sources responsible for a substantial amount of domestic and commercial electricity consumption. Yiru Sun, Noel C. Giebink, Hiroshi Kanno, Biwu Ma, Mark E. Thompson and Stephen R. Forrest Abstract: http://www.nature.com/nature/jou ... bs/nature04645.html Article: http://www.nature.com/nature/jou ... ll/nature04645.html Deep origin and hot melting of an Archaean orogenic peridotite massif in Norway Dirk Spengler, Herman L. M. van Roermund, Martyn R. Drury, Luisa Ottolini, Paul R. D. Mason and Gareth R. Davies Abstract: http://www.nature.com/nature/jou ... bs/nature04644.html Article: http://www.nature.com/nature/jou ... ll/nature04644.html A microbial consortium couples anaerobic methane oxidation to denitrification Although much speculated on, this is the first unambiguous report demonstrating the isolation of a consortium of microorganisms capable of anaerobic methane oxidation using nitrate as the sole electron acceptor. Ashna A. Raghoebarsing, Arjan Pol, Katinka T. van de Pas-Schoonen, Alfons J. P. Smolders, Katharina F. Ettwig, W. Irene C. Rijpstra, Stefan Schouten, Jaap S. Sinninghe Damste, Huub J. M. Op den Camp, Mike S. M. Jetten and Marc Strous Abstract: http://www.nature.com/nature/jou ... bs/nature04617.html Article: http://www.nature.com/nature/jou ... ll/nature04617.html Nitrogen limitation constrains sustainability of ecosystem response to CO2 Peter B. Reich, Sarah E. Hobbie, Tali Lee, David S. Ellsworth, Jason B. West, David Tilman, Johannes M. H. Knops, Shahid Naeem and Jared Trost Abstract: http://www.nature.com/nature/jou ... bs/nature04486.html Article: http://www.nature.com/nature/jou ... ll/nature04486.html Parental investment by skin feeding in a caecilian amphibian Alexander Kupfer, Hendrik Muller, Marta M. Antoniazzi, Carlos Jared, Hartmut Greven, Ronald A. Nussbaum and Mark Wilkinson Abstract: http://www.nature.com/nature/jou ... bs/nature04403.html Article: http://www.nature.com/nature/jou ... ll/nature04403.html Independent evolution of bitter-taste sensitivity in humans and chimpanzees Stephen Wooding, Bernd Bufe, Christina Grassi, Michael T. Howard, Anne C. Stone, Maribel Vazquez, Diane M. Dunn, Wolfgang Meyerhof, Robert B. Weiss and Michael J. Bamshad Abstract: http://www.nature.com/nature/jou ... bs/nature04655.html Article: http://www.nature.com/nature/jou ... ll/nature04655.html STED microscopy reveals that synaptotagmin remains clustered after synaptic vesicle exocytosis Katrin I. Willig, Silvio O. Rizzoli, Volker Westphal, Reinhard Jahn and Stefan W. Hell Abstract: http://www.nature.com/nature/jou ... bs/nature04592.html Article: http://www.nature.com/nature/jou ... ll/nature04592.html Production of the antimalarial drug precursor artemisinic acid in engineered yeast Through the bio-engineering of Saccharomyces cerevisiae high titres of artemisinic acid were produced using a novel cytochrome P450 monooxygenase. Optimization of this process on an industrial scale may significantly reduce the cost of artemisinin, which could then be used to combat malaria in resource-poor settings. Dae-Kyun Ro, Eric M. Paradise, Mario Ouellet, Karl J. Fisher, Karyn L. Newman, John M. Ndungu, Kimberly A. Ho, Rachel A. Eachus, Timothy S. Ham, James Kirby, Michelle C. Y. Chang, Sydnor T. Withers, Yoichiro Shiba, Richmond Sarpong and Jay D. Keasling Abstract: http://www.nature.com/nature/jou ... bs/nature04640.html Article: http://www.nature.com/nature/jou ... ll/nature04640.html Reactive oxygen species have a causal role in multiple forms of insulin resistance Nicholas Houstis, Evan D. Rosen and Eric S. Lander Abstract: http://www.nature.com/nature/jou ... bs/nature04634.html Article: http://www.nature.com/nature/jou ... ll/nature04634.html IκB kinase-α is critical for interferon-α production induced by Toll-like receptors 7 and 9 Katsuaki Hoshino, Takahiro Sugiyama, Mitsuru Matsumoto, Takashi Tanaka, Masuyoshi Saito, Hiroaki Hemmi, Osamu Ohara, Shizuo Akira and Tsuneyasu Kaisho Abstract: http://www.nature.com/nature/jou ... bs/nature04641.html Article: http://www.nature.com/nature/jou ... ll/nature04641.html The reversibility of mitotic exit in vertebrate cells Cells proceed through the cell cycle in a highly ordered and unidirectional manner; however, if the degradation of cyclin B is prevented as cells exit mitosis and its associated Cdk1 kinase activity restored, cells can reverse back to M phase. Tamara A. Potapova, John R. Daum, Bradley D. Pittman, Joanna R. Hudson, Tara N. Jones, David L. Satinover, P. Todd Stukenberg and Gary J. Gorbsky Abstract: http://www.nature.com/nature/jou ... bs/nature04652.html Article: http://www.nature.com/nature/jou ... ll/nature04652.html Toxin-induced conformational changes in a potassium channel revealed by solid-state NMR Adam Lange, Karin Giller, Sonke Hornig, Marie-France Martin-Eauclaire, Olaf Pongs, Stefan Becker and Marc Baldus Abstract: http://www.nature.com/nature/jou ... bs/nature04649.html Article: http://www.nature.com/nature/jou ... ll/nature04649.html ***** |
2楼2006-04-15 15:01:46
100