《Nature》目录要览：2009-10-01出版
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《Nature》目录要览：2009-10-01出版
封面故事：纪念柏林墙倒塌20周年
Cover caption
当柏林墙20年前倒塌时，其所产生的很多后果之一是，世界向东欧科学家敞开了大门。在本期Nature上，我们通过一系列特写文章来纪念这一事件20周年。Quirin Schiermier就研究人员所发生的变化对他们进行了采访（586页），并以引用指数和其他指标为尺度对整个东欧国家的科研现状做了总结（590页）。在一篇“Opinion”文章中，Kristie Macrakis回顾了东德国家安全部（秘密警察）的情况，那是人们最不愿记起的那个时代的机构之一，特别是该机构在国外进行的旨在从西方窃取科技情报的相关间谍活动（594页）。另请看本期的社论文章（569页）和网上相关内容。本期封面所示为柏林墙。
气溶胶怎样影响云和雨的形成（Reach for the clouds）
Untangling aerosol effects on clouds and precipitation in a buffered system
我们知道，大气气溶胶颗粒是云存在的关键。人们认为，气溶胶会影响云形成降雨及造成阴天的能力。但具体来说，云是怎样依赖于气溶胶的？全球气候系统的辐射力又是怎样通过它们依赖于气溶胶的？Bjorn Stevens 和 Graham Feingold提出，过去在分析气溶胶、云和雨之间关系中所存在的困难，部分反映了我们未能将缓冲云和雨对气溶胶扰动之响应的很多过程考虑进去。Stevens 和Feingold说，为了解决这一问题，研究工作需要着重去了解气溶胶、云和雨的特定体系。（Review Article p. 607）
Wnt通道抑制药物的作用目标（Target for Wnt inhibitors）
Tankyrase inhibition stabilizes axin and antagonizes Wnt signalling
Wnt通道（胚胎形成及活细胞中很多其他过程中所涉及的一个信号系统）的失调已被发现与很多癌症有关，这使得它成为抗癌疗法的一个有吸引力的目标。但虽然Notch和Hedgehog通道的抑制药物已进入临床试验阶段，Wnt抑制药物可发挥作用的目标却难以确定。现在，研究人员利用一种化学遗传学方法发现了Wnt通道的一个小分子抑制药物，并且对其直接目标和作用机制做了定性。XAV939能通过稳定Axin（Beta-catenin降解复合物的一个浓度限制因子）高效抑制Wnt信号作用。这项工作除了提出新的药物作用目标外，还为了解Wnt通道的生理调控方式提供了见解。（Article p. 614; News & Views）
能够选择性抑制结核分枝杆菌蛋白酶体的新药物（New anti-TB approach）
Inhibitors selective for mycobacterial versus human proteasomes
蛋白酶体（分解多余或受损蛋白的蛋白复合物）在结构上是从古细菌到真核生物一直保留下来的。蛋白酶体抑制药物已被用于癌症治疗，而且也被建议用于真核病原体如疟原虫和锥体虫所造成感染的治疗，但蛋白酶体抑制药物所固有的毒性是其在可治愈型感染的治疗中的一个缺陷。分枝杆菌是已知含蛋白酶体的惟一细菌病原体，能够选择性抑制结核分枝杆菌蛋白酶体的一组新的小分子的发现让我们看到一个希望：抗蛋白酶体药物也许会被证明是治疗结核病的高选择性药物。新发现的药物是“oxathiazol-2-ones”，它们以非可逆方式与结核分枝杆菌蛋白酶体结合，同时基本上会放过人体的蛋白酶体。（Article p. 621）
星系中暗物质和亮物质分布之间的关系（Lightening the darkness）
Universality of galactic surface densities within one dark halo scale-length
所有星系都被认为由一个光晕包围，这个光晕由“暗物质”组成，它们看不见，只能通过其引力相互作用检测到。Gentile等人报告，他们在星系中暗物质和亮物质的分布之间发现了一个令人吃惊的关系，这个关系涉及一系列观测特性。他们发现，在一个暗光晕标尺长度内，平均亮物质表面密度对几乎所有形状和大小的星系来说都是恒定的。此前还有一个发现：一个暗光晕标尺长度（该长度指一个范围的半径，在该范围内，暗物质的体密度分布保持不变）内的平均暗物质表面密度对所有星系都几乎是恒定的。（Letter p. 627）
用X-射线方法分析不稳定中间体的结构Chemical reactions X-rayed
X-ray observation of a transient hemiaminal trapped in a porous network
对于稳定晶体化合物的结构分析来说，X-射线结晶学是首选方法。但不稳定的反应中间体却是这种方法所不能分析的。现在，Kawamichi等人解决了这一问题。他们的办法是，设计一种稳定的多孔网状材料，它起一个“反应介质”的作用，化学反应在小孔内发生。然后，可用X-射线分析来对反应的不同阶段进行拍摄。在一项原理证明实验中，他们确定了一个多孔网络的结构：先是将一个芳族胺嵌入在该网络中，然后将一个乙醛基质扩散进该材料中，形成一个半酰胺中间体，最后形成亚胺产物。（Letter p. 633; News & Views）
大地震对断层强度可能具有全球性影响（Earthquakes find fault）
Remote triggering of fault-strength changes on the San Andreas fault at Parkfield
来自圣安得列斯断层Parkfield地区的一个时间跨度为20年的地震记录，被用来识别两起事件，在这两起事件中，断层强度的长期变化似乎都是由远处发生的大地震诱发的： 2004年的苏门答腊-安达曼地震和1992年的兰德斯地震。在这两起事件中，发生了两个与断层强度变化相一致的变化：地震波传播物的性质随时间的变化（反映了应力诱导的流体迁移）和重复地震序列的特点的系统性变化。这些发现表明，大地震对地球断层体系的强度有一个全球性影响。作为对该假说的支持，研究人员还发现，在2004年苏门答腊-安达曼地震后的三年里，震级大于或等于8级的地震发生的次数异乎寻常地多。（Letter p. 636）
郝氏近鸟实际上是伤齿龙（Anchiornis huxleyi: strictly for the troodontids）
A pre-Archaeopteryx troodontid theropod from China with long feathers on the metatarsus
伤齿龙和驰龙是与鸟类关系最近的恐龙。来自中国侏罗纪地层的郝氏近鸟（Anchiornis huxleyi）过去被认为是一种基础的鸟类，正处在积累鸟类特征的过程中，但仍保留其更早先祖的显著特征。然而，一个新的、引人注目的标本的发现表明，它实际上是一种伤齿龙。因此，它是该类别当中一个非常早的成员（早于始祖鸟），长有丰富的羽毛，尤其是在腿上和脚上。近鸟类（伤齿龙、驰龙和鸟类）的早期历史，过去显然是一个人们进行大量演化实验研究、并存在很大争议的历史，只是现在才随着新的化石发现的获得而变得明朗。（Letter p. 640; News & Views）
OCT4独自能从人神经干细胞产生iPS细胞（Human iPS cells made simpler）
Direct reprogramming of human neural stem cells by OCT4
今年早些时候，Hans Schöler的小组报告，仅一个转录因子OCT4就足以使小鼠成年神经干细胞重新编程，成为多能细胞，使它们能够在合适的条件下生成几乎任何一种类型的细胞。这是对该过程的一个非常大的简化——OCT4仅仅是在早期（2006/7年）关于产生诱导多能干细胞（iPS细胞）的经典研究工作中所用的四个因子之一。现在，Schöler及其同事发现，OCT4独自还能从人神经干细胞产生iPS细胞。（Letter p. 649）
跨膜蛋白FasL与细胞凋亡无关的功能（FasL’s non-apoptotic functions）
Membrane-bound Fas ligand only is essential for Fas-induced apoptosis
名为FasL (Fas ligand)的跨膜蛋白是在免疫调控中有重要作用的肿瘤坏死因子家族中的一员。FasL与其受体的结合诱导细胞凋亡，但尚不清楚细胞死亡对FasL的细胞功能有多重要。用剔除相关基因的突变小鼠（它们缺失分泌的FasL、但却表达正常水平的与膜结合的FasL；或者缺失与膜结合的FasL、但却仍能产生分泌的FasL）所做实验表明，可溶FasL通过不涉及细胞凋亡的机制促进自体免疫和肿瘤形成。（Letter p. 659）
病毒装填马达与核酸磷酸盐骨架的互动方式（Viral packaging）
Substrate interactions and promiscuity in a viral DNA packaging motor
“病毒装填马达”（ASCE超级家族的多聚环状ATP酶）通过以一种依赖于核苷酸的方式沿核酸单向转位，来调控病毒基因组对衣壳的填充。Aathaven等人利用单分子方法来确定在枯草芽孢杆菌噬菌体29的装填过程中，该马达蛋白怎样与核酸的磷酸盐骨架发生相互作用。他们发现，磷酸盐的电荷有助于转位，但并不是转位所必需的。事实上，装填马达的选择性非常差，甚至一个非生物聚合物也可以被装填进去。然而正常情况下，这个马达在大约每10个碱基对有一个磷酸盐电荷的一条链上与磷酸盐骨架发生相互作用。（Letter p. 669）
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NEWS AND VIEWS
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Drug discovery: Propping up a destructive regime pp599-600
The Wnt signalling pathway balances the opposing activities of two
proteins to transmit signals within cells. An inhibitor that stabilizes
one of these proteins reveals a new target for anticancer drug development.
Randall T. Peterson
doi:10.1038/461599a
http://www.nature.com/nature/journal/v461/n7264/full/461599a.html
Optics: Droplets set light in a spin pp600-601
Fusilli pasta is made by extruding dough through an appropriately
shaped hole. A new method for making similar shapes in the optical
field of light involves passing laser beams through droplets of liquid crystals.
Miles Padgett
doi:10.1038/461600a
http://www.nature.com/nature/journal/v461/n7264/full/461600a.html
Palaeontology: Feathered dinosaurs in a tangle pp601-602
A dramatic feathered dinosaur fossil from the Jurassic of China resolves
a 'temporal paradox'. But it adds intriguing complications to the debates
on the evolution of feathers and flight in birds.
Lawrence M. Witmer
doi:10.1038/461601a
http://www.nature.com/nature/journal/v461/n7264/full/461601a.html
Supramolecular chemistry: Molecular crystal balls pp602-603
Sorcerers have long gazed into crystal balls to conjure up information.
Chemists are also getting in on the act, using porous crystals to trap
unstable reaction intermediates and to reveal their structures.
Seth M. Cohen
doi:10.1038/461602a
http://www.nature.com/nature/journal/v461/n7264/full/461602a.html
Behavioural ecology: Winged warnings pp603-604
Alarm signals emitted by animals may not be all that they seem. But
a good example has been identified in the whistling sound of a crested
pigeon's wings when it takes flight in response to a predator.
Graeme D. Ruxton
doi:10.1038/461603a
http://www.nature.com/nature/journal/v461/n7264/full/461603a.html
50 & 100 years ago p604
doi:10.1038/461604b
http://www.nature.com/nature/journal/v461/n7264/full/461604b.html
Applied physics: Lasers go nano pp604-605
Two experiments that produce laser light by exploiting the collective
wave-like motion of free electrons on a metal surface bring the science
and technology of lasers into the nanoland.
Francisco J. Garcia-Vidal and Esteban Moreno
doi:10.1038/461604a
http://www.nature.com/nature/journal/v461/n7264/full/461604a.html
Correction p605
doi:10.1038/461605a
http://www.nature.com/nature/journal/v461/n7264/full/461605a.html
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REVIEW
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Untangling aerosol effects on clouds and precipitation in a buffered system pp607-613
Bjorn Stevens and Graham Feingold
doi:10.1038/nature08281
Abstract: http://www.nature.com/nature/journal/v461/n7264/abs/nature08281.html
Article: http://www.nature.com/nature/journal/v461/n7264/full/nature08281.html
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ARTICLES
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Tankyrase inhibition stabilizes axin and antagonizes Wnt signalling pp614-620
Deregulated Wnt pathway activity has been implicated in many cancers, making
this pathway an attractive target for anticancer therapies. Here, a small
molecule inhibitor of the Wnt pathway is identified and its direct target
and mechanism of action are characterized, providing new insights into the
physiological regulation of the Wnt pathway and new possibilities for
targeted Wnt pathway therapeutics.
Shih-Min A. Huang et al.
doi:10.1038/nature08356
Abstract: http://www.nature.com/nature/journal/v461/n7264/abs/nature08356.html
Article: http://www.nature.com/nature/journal/v461/n7264/full/nature08356.html
Inhibitors selective for mycobacterial versus human proteasomes pp621-626
Proteasome structure is extensively conserved across a broad range of
organisms, so it is not surprising that inhibitors of all chemical classes
tested have blocked both eukaryotic and prokaryotic proteasomes. However,
certain oxathiazol-2-one compounds are now shown to kill non-replicating
Mycobacterium tuberculosis and act as selective inhibitors of the M.
tuberculosis proteasome while largely sparing the human homologue.
Gang Lin et al.
doi:10.1038/nature08357
Abstract: http://www.nature.com/nature/journal/v461/n7264/abs/nature08357.html
Article: http://www.nature.com/nature/journal/v461/n7264/full/nature08357.html
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LETTERS
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Universality of galactic surface densities within one dark halo scale-length
pp627-628
Mean dark matter surface density within one dark-halo scale-length was recently
discovered to be constant across a wide range of galaxies. Here, the luminous
matter surface density is reported to also be constant within one scale-length
of the dark halo, such that although the total luminous-to-dark matter ratio
is not constant, within one halo scale-length it is constant.
Gianfranco Gentile, Benoit Famaey, HongSheng Zhao and Paolo Salucci
doi:10.1038/nature08437
Abstract: http://www.nature.com/nature/journal/v461/n7264/abs/nature08437.html
Article: http://www.nature.com/nature/journal/v461/n7264/full/nature08437.html
Plasmon lasers at deep subwavelength scale pp629-632
A key challenge is to realize ultracompact lasers that can directly generate
coherent optical fields at the nanometre scale, far beyond the diffraction
limit. Surface plasmons could be used to tightly confine light on very short
lengthscales, but so far this approach has been hampered by ohmic losses at
optical frequencies. The experimental demonstration of nanometre-scale plasmonic
lasers is now reported, realized using a hybrid plasmonic waveguide -
these lasers can generate optical modes a hundred times smaller than the diffraction limit.
Rupert F. Oulton et al.
doi:10.1038/nature08364
Abstract: http://www.nature.com/nature/journal/v461/n7264/abs/nature08364.html
Article: http://www.nature.com/nature/journal/v461/n7264/full/nature08364.html
X-ray observation of a transient hemiaminal trapped in a porous network pp633-635
Although X-ray crystallography is the method of choice for the direct structural
analysis of crystalline compounds, extending its use to the in situ mapping of
chemical transformations involving unstable intermediates is challenging. Here
this is achieved by using a porous network material as a 'reaction medium' to
enable X-ray observations of reaction intermediates that are usually transient
and non-isolable.
Takehide Kawamichi, Tsuyoshi Haneda, Masaki Kawano and Makoto Fujita
doi:10.1038/nature08326
Abstract: http://www.nature.com/nature/journal/v461/n7264/abs/nature08326.html
Article: http://www.nature.com/nature/journal/v461/n7264/full/nature08326.html
Remote triggering of fault-strength changes on the San Andreas fault at Parkfield pp636-639
Changes in fault strength over time can increase or decrease the likelihood of
failure and the ultimate triggering of seismic events. Observation of the
Parkfield area at the San Andreas fault over the years 1987-2008 now reveals
two occasions [mdash] the 2004 Sumatra-Andaman earthquake and the 1992 Landers
earthquake - where long-term changes in fault strength have probably been
induced remotely by large seismic events.
Taka/'aki Taira, Paul G. Silver, Fenglin Niu and Robert M. Nadeau
doi:10.1038/nature08395
Abstract: http://www.nature.com/nature/journal/v461/n7264/abs/nature08395.html
Article: http://www.nature.com/nature/journal/v461/n7264/full/nature08395.html
A pre-Archaeopteryx troodontid theropod from China with long feathers on the metatarsus
The early evolution of the major groups of derived non-avialan theropods is not
well understood, resulting in the 'temporal paradox' argument against the theropod
hypothesis of avian origins. Here, a small theropod specimen collected from the
earliest Late Jurassic of China is recovered that is referable to the Troodontidae,
which are among the theropods most closely related to birds, thus refuting the
'temporal paradox'. Furthermore, the extensive feathering of the specimen sheds
new light on the early evolution of feathers.
Dongyu Hu, Lianhai Hou, Lijun Zhang and Xing Xu
doi:10.1038/nature08322
Abstract: http://www.nature.com/nature/journal/vaop/ncurrent/full/nature08322.html
Article: http://www.nature.com/nature/journal/vaop/ncurrent/full/nature08322.html
Robust discrimination between self and non-self neurites requires thousands of
Dscam1 isoforms pp644-648
The tendency of branches from the same neuron (self-branches) to selectively
avoid one another is known as self-avoidance. The expression of different
isoforms of the Down Syndrome cell adhesion molecule (Dscam) gene, which
expresses a neuronal cell recognition protein of the immunoglobulin superfamily,
ensures that repulsion is restricted to self-branches. Here, in Drosophila,
the number of isoforms of Dscam1 required to prevent non-self branches from
recognizing each other is determined.
Daisuke Hattori et al.
doi:10.1038/nature08431
Abstract: http://www.nature.com/nature/journal/v461/n7264/abs/nature08431.html
Article: http://www.nature.com/nature/journal/v461/n7264/full/nature08431.html
Direct reprogramming of human neural stem cells by OCT4 p649
Although induced pluripotent stem (iPS) cells have been generated from mouse and
human somatic cells by ectopic expression of four transcription factors, the
expression of one of these four, Oct4, is sufficient to directly reprogram adult
mouse neural stem cells to iPS cells. The generation of one-factor human iPS
cells from human fetal neural stem cells by ectopic expression of OCT4 alone
is now reported, demonstrating that OCT4 is sufficient to reprogram human neural
stem cells to pluripotency.
Jeong Beom Kim et al.
doi:10.1038/nature08436
Abstract: http://www.nature.com/nature/journal/v461/n7264/abs/nature08436.html
Article: http://www.nature.com/nature/journal/v461/n7264/full/nature08436.html
Discovery of Atg5/Atg7-independent alternative macroautophagy pp654-658
Macroautophagy is the process by which defective proteins and entire organelles
are sequestered in membrane compartments called autophagosomes, which ultimately
fuse with lysosomes and undergo degradation. The genes Atg5 and Atg7 are believed
to be essential for mammalian macroautophagy. Here it is shown, however, that
under certain stress conditions mouse cells lacking Atg5 or Atg7 can still
perform autophagy-mediated protein degradation through an alternative pathway.
Yuya Nishida et al.
doi:10.1038/nature08455
Abstract: http://www.nature.com/nature/journal/v461/n7264/abs/nature08455.html
Article: http://www.nature.com/nature/journal/v461/n7264/full/nature08455.html
Membrane-bound Fas ligand only is essential for Fas-induced apoptosis pp659-663
Fas ligand (FasL) and its receptor Fas are critical for the shutdown of chronic
immune responses and prevention of autoimmunity. FasL function is regulated by
deposition in the plasma membrane and metalloprotease-mediated shedding, but it
is unclear what the respective roles of these secreted and membrane-bound forms
are. Gene-targeted mice that selectively lack either secreted FasL or membrane-
bound FasL are now generated, shedding light on this problem.
Lorraine A. O/' Reilly et al.
doi:10.1038/nature08402
Abstract: http://www.nature.com/nature/journal/v461/n7264/abs/nature08402.html
Article: http://www.nature.com/nature/journal/v461/n7264/full/nature08402.html
Cooperative binding of two acetylation marks on a histone tail by a single
bromodomain pp664-668
The recognition of histone post-translational modifications by effector modules
such as bromodomains is a key step in many chromatin-related processes. Although
effector-mediated recognition of single post-translation modifications is well
characterized, combinatorial readout of histones bearing multiple modifications
is poorly understood. Here, a distinct mechanism of combinatorial readout for
the mouse TAF1 homologue Brdt, a testis-specific member of the BET protein family, is reported.
Jeanne Moriniere et al.
doi:10.1038/nature08397
Abstract: http://www.nature.com/nature/journal/v461/n7264/abs/nature08397.html
Article: http://www.nature.com/nature/journal/v461/n7264/full/nature08397.html
Substrate interactions and promiscuity in a viral DNA packaging motor pp669-673
In several viruses and bacteriophages, DNA transport in processes such as genome
packaging is dependent on a subset of the ASCE superfamily of protein enzymes
consisting of multimeric ringed pumps. Little is known, however, about how these
motors engage their nucleic acid substrates. Here, the genome packaging motor of
the Bacillus subtilis bacteriophage is studied, revealing that the full
mechanochemical cycle of the motor involves two, rather different, phases.
K. Aathavan et al.
doi:10.1038/nature08443
Abstract: http://www.nature.com/nature/journal/v461/n7264/abs/nature08443.html
Article: http://www.nature.com/nature/journal/v461/n7264/full/nature08443.html
A human 5[prime]-tyrosyl DNA phosphodiesterase that repairs topoisomerase-mediated
DNA damage pp674-678
The mechanism of topoisomerase action involves making a transient break in DNA,
which, if it occurs near another DNA lesion, can persist, with the topoisomerase
attached the 3[prime] or 5[prime] end by a phosphotyrosyl bond. If the DNA termini
are not liberated from the topoisomerase, cancer and neurodegenerative disease
may result. A human enzyme that cleaves 3[prime]-phosphotyrosyl bonds has already
been identified; a complementary enzyme that cleaves 5[prime]-phosphotyrosyl
bonds is now reported.
Felipe Cortes Ledesma et al.
doi:10.1038/nature08444
Abstract: http://www.nature.com/nature/journal/v461/n7264/abs/nature08444.html
Article: http://www.nature.com/nature/journal/v461/n7264/full/nature08444.html
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FUTURES
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Quality control p686
A palpable hit.
Marissa Lingen
doi:10.1038/461686a
http://www.nature.com/nature/journal/v461/n7264/full/461686a.html
Cover caption
当柏林墙20年前倒塌时，其所产生的很多后果之一是，世界向东欧科学家敞开了大门。在本期Nature上，我们通过一系列特写文章来纪念这一事件20周年。Quirin Schiermier就研究人员所发生的变化对他们进行了采访（586页），并以引用指数和其他指标为尺度对整个东欧国家的科研现状做了总结（590页）。在一篇“Opinion”文章中，Kristie Macrakis回顾了东德国家安全部（秘密警察）的情况，那是人们最不愿记起的那个时代的机构之一，特别是该机构在国外进行的旨在从西方窃取科技情报的相关间谍活动（594页）。另请看本期的社论文章（569页）和网上相关内容。本期封面所示为柏林墙。
气溶胶怎样影响云和雨的形成（Reach for the clouds）
Untangling aerosol effects on clouds and precipitation in a buffered system
我们知道，大气气溶胶颗粒是云存在的关键。人们认为，气溶胶会影响云形成降雨及造成阴天的能力。但具体来说，云是怎样依赖于气溶胶的？全球气候系统的辐射力又是怎样通过它们依赖于气溶胶的？Bjorn Stevens 和 Graham Feingold提出，过去在分析气溶胶、云和雨之间关系中所存在的困难，部分反映了我们未能将缓冲云和雨对气溶胶扰动之响应的很多过程考虑进去。Stevens 和Feingold说，为了解决这一问题，研究工作需要着重去了解气溶胶、云和雨的特定体系。（Review Article p. 607）
Wnt通道抑制药物的作用目标（Target for Wnt inhibitors）
Tankyrase inhibition stabilizes axin and antagonizes Wnt signalling
Wnt通道（胚胎形成及活细胞中很多其他过程中所涉及的一个信号系统）的失调已被发现与很多癌症有关，这使得它成为抗癌疗法的一个有吸引力的目标。但虽然Notch和Hedgehog通道的抑制药物已进入临床试验阶段，Wnt抑制药物可发挥作用的目标却难以确定。现在，研究人员利用一种化学遗传学方法发现了Wnt通道的一个小分子抑制药物，并且对其直接目标和作用机制做了定性。XAV939能通过稳定Axin（Beta-catenin降解复合物的一个浓度限制因子）高效抑制Wnt信号作用。这项工作除了提出新的药物作用目标外，还为了解Wnt通道的生理调控方式提供了见解。（Article p. 614; News & Views）
能够选择性抑制结核分枝杆菌蛋白酶体的新药物（New anti-TB approach）
Inhibitors selective for mycobacterial versus human proteasomes
蛋白酶体（分解多余或受损蛋白的蛋白复合物）在结构上是从古细菌到真核生物一直保留下来的。蛋白酶体抑制药物已被用于癌症治疗，而且也被建议用于真核病原体如疟原虫和锥体虫所造成感染的治疗，但蛋白酶体抑制药物所固有的毒性是其在可治愈型感染的治疗中的一个缺陷。分枝杆菌是已知含蛋白酶体的惟一细菌病原体，能够选择性抑制结核分枝杆菌蛋白酶体的一组新的小分子的发现让我们看到一个希望：抗蛋白酶体药物也许会被证明是治疗结核病的高选择性药物。新发现的药物是“oxathiazol-2-ones”，它们以非可逆方式与结核分枝杆菌蛋白酶体结合，同时基本上会放过人体的蛋白酶体。（Article p. 621）
星系中暗物质和亮物质分布之间的关系（Lightening the darkness）
Universality of galactic surface densities within one dark halo scale-length
所有星系都被认为由一个光晕包围，这个光晕由“暗物质”组成，它们看不见，只能通过其引力相互作用检测到。Gentile等人报告，他们在星系中暗物质和亮物质的分布之间发现了一个令人吃惊的关系，这个关系涉及一系列观测特性。他们发现，在一个暗光晕标尺长度内，平均亮物质表面密度对几乎所有形状和大小的星系来说都是恒定的。此前还有一个发现：一个暗光晕标尺长度（该长度指一个范围的半径，在该范围内，暗物质的体密度分布保持不变）内的平均暗物质表面密度对所有星系都几乎是恒定的。（Letter p. 627）
用X-射线方法分析不稳定中间体的结构Chemical reactions X-rayed
X-ray observation of a transient hemiaminal trapped in a porous network
对于稳定晶体化合物的结构分析来说，X-射线结晶学是首选方法。但不稳定的反应中间体却是这种方法所不能分析的。现在，Kawamichi等人解决了这一问题。他们的办法是，设计一种稳定的多孔网状材料，它起一个“反应介质”的作用，化学反应在小孔内发生。然后，可用X-射线分析来对反应的不同阶段进行拍摄。在一项原理证明实验中，他们确定了一个多孔网络的结构：先是将一个芳族胺嵌入在该网络中，然后将一个乙醛基质扩散进该材料中，形成一个半酰胺中间体，最后形成亚胺产物。（Letter p. 633; News & Views）
大地震对断层强度可能具有全球性影响（Earthquakes find fault）
Remote triggering of fault-strength changes on the San Andreas fault at Parkfield
来自圣安得列斯断层Parkfield地区的一个时间跨度为20年的地震记录，被用来识别两起事件，在这两起事件中，断层强度的长期变化似乎都是由远处发生的大地震诱发的： 2004年的苏门答腊-安达曼地震和1992年的兰德斯地震。在这两起事件中，发生了两个与断层强度变化相一致的变化：地震波传播物的性质随时间的变化（反映了应力诱导的流体迁移）和重复地震序列的特点的系统性变化。这些发现表明，大地震对地球断层体系的强度有一个全球性影响。作为对该假说的支持，研究人员还发现，在2004年苏门答腊-安达曼地震后的三年里，震级大于或等于8级的地震发生的次数异乎寻常地多。（Letter p. 636）
郝氏近鸟实际上是伤齿龙（Anchiornis huxleyi: strictly for the troodontids）
A pre-Archaeopteryx troodontid theropod from China with long feathers on the metatarsus
伤齿龙和驰龙是与鸟类关系最近的恐龙。来自中国侏罗纪地层的郝氏近鸟（Anchiornis huxleyi）过去被认为是一种基础的鸟类，正处在积累鸟类特征的过程中，但仍保留其更早先祖的显著特征。然而，一个新的、引人注目的标本的发现表明，它实际上是一种伤齿龙。因此，它是该类别当中一个非常早的成员（早于始祖鸟），长有丰富的羽毛，尤其是在腿上和脚上。近鸟类（伤齿龙、驰龙和鸟类）的早期历史，过去显然是一个人们进行大量演化实验研究、并存在很大争议的历史，只是现在才随着新的化石发现的获得而变得明朗。（Letter p. 640; News & Views）
OCT4独自能从人神经干细胞产生iPS细胞（Human iPS cells made simpler）
Direct reprogramming of human neural stem cells by OCT4
今年早些时候，Hans Schöler的小组报告，仅一个转录因子OCT4就足以使小鼠成年神经干细胞重新编程，成为多能细胞，使它们能够在合适的条件下生成几乎任何一种类型的细胞。这是对该过程的一个非常大的简化——OCT4仅仅是在早期（2006/7年）关于产生诱导多能干细胞（iPS细胞）的经典研究工作中所用的四个因子之一。现在，Schöler及其同事发现，OCT4独自还能从人神经干细胞产生iPS细胞。（Letter p. 649）
跨膜蛋白FasL与细胞凋亡无关的功能（FasL’s non-apoptotic functions）
Membrane-bound Fas ligand only is essential for Fas-induced apoptosis
名为FasL (Fas ligand)的跨膜蛋白是在免疫调控中有重要作用的肿瘤坏死因子家族中的一员。FasL与其受体的结合诱导细胞凋亡，但尚不清楚细胞死亡对FasL的细胞功能有多重要。用剔除相关基因的突变小鼠（它们缺失分泌的FasL、但却表达正常水平的与膜结合的FasL；或者缺失与膜结合的FasL、但却仍能产生分泌的FasL）所做实验表明，可溶FasL通过不涉及细胞凋亡的机制促进自体免疫和肿瘤形成。（Letter p. 659）
病毒装填马达与核酸磷酸盐骨架的互动方式（Viral packaging）
Substrate interactions and promiscuity in a viral DNA packaging motor
“病毒装填马达”（ASCE超级家族的多聚环状ATP酶）通过以一种依赖于核苷酸的方式沿核酸单向转位，来调控病毒基因组对衣壳的填充。Aathaven等人利用单分子方法来确定在枯草芽孢杆菌噬菌体29的装填过程中，该马达蛋白怎样与核酸的磷酸盐骨架发生相互作用。他们发现，磷酸盐的电荷有助于转位，但并不是转位所必需的。事实上，装填马达的选择性非常差，甚至一个非生物聚合物也可以被装填进去。然而正常情况下，这个马达在大约每10个碱基对有一个磷酸盐电荷的一条链上与磷酸盐骨架发生相互作用。（Letter p. 669）
----------------------
NEWS AND VIEWS
----------------------
Drug discovery: Propping up a destructive regime pp599-600
The Wnt signalling pathway balances the opposing activities of two
proteins to transmit signals within cells. An inhibitor that stabilizes
one of these proteins reveals a new target for anticancer drug development.
Randall T. Peterson
doi:10.1038/461599a
http://www.nature.com/nature/journal/v461/n7264/full/461599a.html
Optics: Droplets set light in a spin pp600-601
Fusilli pasta is made by extruding dough through an appropriately
shaped hole. A new method for making similar shapes in the optical
field of light involves passing laser beams through droplets of liquid crystals.
Miles Padgett
doi:10.1038/461600a
http://www.nature.com/nature/journal/v461/n7264/full/461600a.html
Palaeontology: Feathered dinosaurs in a tangle pp601-602
A dramatic feathered dinosaur fossil from the Jurassic of China resolves
a 'temporal paradox'. But it adds intriguing complications to the debates
on the evolution of feathers and flight in birds.
Lawrence M. Witmer
doi:10.1038/461601a
http://www.nature.com/nature/journal/v461/n7264/full/461601a.html
Supramolecular chemistry: Molecular crystal balls pp602-603
Sorcerers have long gazed into crystal balls to conjure up information.
Chemists are also getting in on the act, using porous crystals to trap
unstable reaction intermediates and to reveal their structures.
Seth M. Cohen
doi:10.1038/461602a
http://www.nature.com/nature/journal/v461/n7264/full/461602a.html
Behavioural ecology: Winged warnings pp603-604
Alarm signals emitted by animals may not be all that they seem. But
a good example has been identified in the whistling sound of a crested
pigeon's wings when it takes flight in response to a predator.
Graeme D. Ruxton
doi:10.1038/461603a
http://www.nature.com/nature/journal/v461/n7264/full/461603a.html
50 & 100 years ago p604
doi:10.1038/461604b
http://www.nature.com/nature/journal/v461/n7264/full/461604b.html
Applied physics: Lasers go nano pp604-605
Two experiments that produce laser light by exploiting the collective
wave-like motion of free electrons on a metal surface bring the science
and technology of lasers into the nanoland.
Francisco J. Garcia-Vidal and Esteban Moreno
doi:10.1038/461604a
http://www.nature.com/nature/journal/v461/n7264/full/461604a.html
Correction p605
doi:10.1038/461605a
http://www.nature.com/nature/journal/v461/n7264/full/461605a.html
----------------------
REVIEW
----------------------
Untangling aerosol effects on clouds and precipitation in a buffered system pp607-613
Bjorn Stevens and Graham Feingold
doi:10.1038/nature08281
Abstract: http://www.nature.com/nature/journal/v461/n7264/abs/nature08281.html
Article: http://www.nature.com/nature/journal/v461/n7264/full/nature08281.html
----------------------
ARTICLES
----------------------
Tankyrase inhibition stabilizes axin and antagonizes Wnt signalling pp614-620
Deregulated Wnt pathway activity has been implicated in many cancers, making
this pathway an attractive target for anticancer therapies. Here, a small
molecule inhibitor of the Wnt pathway is identified and its direct target
and mechanism of action are characterized, providing new insights into the
physiological regulation of the Wnt pathway and new possibilities for
targeted Wnt pathway therapeutics.
Shih-Min A. Huang et al.
doi:10.1038/nature08356
Abstract: http://www.nature.com/nature/journal/v461/n7264/abs/nature08356.html
Article: http://www.nature.com/nature/journal/v461/n7264/full/nature08356.html
Inhibitors selective for mycobacterial versus human proteasomes pp621-626
Proteasome structure is extensively conserved across a broad range of
organisms, so it is not surprising that inhibitors of all chemical classes
tested have blocked both eukaryotic and prokaryotic proteasomes. However,
certain oxathiazol-2-one compounds are now shown to kill non-replicating
Mycobacterium tuberculosis and act as selective inhibitors of the M.
tuberculosis proteasome while largely sparing the human homologue.
Gang Lin et al.
doi:10.1038/nature08357
Abstract: http://www.nature.com/nature/journal/v461/n7264/abs/nature08357.html
Article: http://www.nature.com/nature/journal/v461/n7264/full/nature08357.html
----------------------
LETTERS
----------------------
Universality of galactic surface densities within one dark halo scale-length
pp627-628
Mean dark matter surface density within one dark-halo scale-length was recently
discovered to be constant across a wide range of galaxies. Here, the luminous
matter surface density is reported to also be constant within one scale-length
of the dark halo, such that although the total luminous-to-dark matter ratio
is not constant, within one halo scale-length it is constant.
Gianfranco Gentile, Benoit Famaey, HongSheng Zhao and Paolo Salucci
doi:10.1038/nature08437
Abstract: http://www.nature.com/nature/journal/v461/n7264/abs/nature08437.html
Article: http://www.nature.com/nature/journal/v461/n7264/full/nature08437.html
Plasmon lasers at deep subwavelength scale pp629-632
A key challenge is to realize ultracompact lasers that can directly generate
coherent optical fields at the nanometre scale, far beyond the diffraction
limit. Surface plasmons could be used to tightly confine light on very short
lengthscales, but so far this approach has been hampered by ohmic losses at
optical frequencies. The experimental demonstration of nanometre-scale plasmonic
lasers is now reported, realized using a hybrid plasmonic waveguide -
these lasers can generate optical modes a hundred times smaller than the diffraction limit.
Rupert F. Oulton et al.
doi:10.1038/nature08364
Abstract: http://www.nature.com/nature/journal/v461/n7264/abs/nature08364.html
Article: http://www.nature.com/nature/journal/v461/n7264/full/nature08364.html
X-ray observation of a transient hemiaminal trapped in a porous network pp633-635
Although X-ray crystallography is the method of choice for the direct structural
analysis of crystalline compounds, extending its use to the in situ mapping of
chemical transformations involving unstable intermediates is challenging. Here
this is achieved by using a porous network material as a 'reaction medium' to
enable X-ray observations of reaction intermediates that are usually transient
and non-isolable.
Takehide Kawamichi, Tsuyoshi Haneda, Masaki Kawano and Makoto Fujita
doi:10.1038/nature08326
Abstract: http://www.nature.com/nature/journal/v461/n7264/abs/nature08326.html
Article: http://www.nature.com/nature/journal/v461/n7264/full/nature08326.html
Remote triggering of fault-strength changes on the San Andreas fault at Parkfield pp636-639
Changes in fault strength over time can increase or decrease the likelihood of
failure and the ultimate triggering of seismic events. Observation of the
Parkfield area at the San Andreas fault over the years 1987-2008 now reveals
two occasions [mdash] the 2004 Sumatra-Andaman earthquake and the 1992 Landers
earthquake - where long-term changes in fault strength have probably been
induced remotely by large seismic events.
Taka/'aki Taira, Paul G. Silver, Fenglin Niu and Robert M. Nadeau
doi:10.1038/nature08395
Abstract: http://www.nature.com/nature/journal/v461/n7264/abs/nature08395.html
Article: http://www.nature.com/nature/journal/v461/n7264/full/nature08395.html
A pre-Archaeopteryx troodontid theropod from China with long feathers on the metatarsus
The early evolution of the major groups of derived non-avialan theropods is not
well understood, resulting in the 'temporal paradox' argument against the theropod
hypothesis of avian origins. Here, a small theropod specimen collected from the
earliest Late Jurassic of China is recovered that is referable to the Troodontidae,
which are among the theropods most closely related to birds, thus refuting the
'temporal paradox'. Furthermore, the extensive feathering of the specimen sheds
new light on the early evolution of feathers.
Dongyu Hu, Lianhai Hou, Lijun Zhang and Xing Xu
doi:10.1038/nature08322
Abstract: http://www.nature.com/nature/journal/vaop/ncurrent/full/nature08322.html
Article: http://www.nature.com/nature/journal/vaop/ncurrent/full/nature08322.html
Robust discrimination between self and non-self neurites requires thousands of
Dscam1 isoforms pp644-648
The tendency of branches from the same neuron (self-branches) to selectively
avoid one another is known as self-avoidance. The expression of different
isoforms of the Down Syndrome cell adhesion molecule (Dscam) gene, which
expresses a neuronal cell recognition protein of the immunoglobulin superfamily,
ensures that repulsion is restricted to self-branches. Here, in Drosophila,
the number of isoforms of Dscam1 required to prevent non-self branches from
recognizing each other is determined.
Daisuke Hattori et al.
doi:10.1038/nature08431
Abstract: http://www.nature.com/nature/journal/v461/n7264/abs/nature08431.html
Article: http://www.nature.com/nature/journal/v461/n7264/full/nature08431.html
Direct reprogramming of human neural stem cells by OCT4 p649
Although induced pluripotent stem (iPS) cells have been generated from mouse and
human somatic cells by ectopic expression of four transcription factors, the
expression of one of these four, Oct4, is sufficient to directly reprogram adult
mouse neural stem cells to iPS cells. The generation of one-factor human iPS
cells from human fetal neural stem cells by ectopic expression of OCT4 alone
is now reported, demonstrating that OCT4 is sufficient to reprogram human neural
stem cells to pluripotency.
Jeong Beom Kim et al.
doi:10.1038/nature08436
Abstract: http://www.nature.com/nature/journal/v461/n7264/abs/nature08436.html
Article: http://www.nature.com/nature/journal/v461/n7264/full/nature08436.html
Discovery of Atg5/Atg7-independent alternative macroautophagy pp654-658
Macroautophagy is the process by which defective proteins and entire organelles
are sequestered in membrane compartments called autophagosomes, which ultimately
fuse with lysosomes and undergo degradation. The genes Atg5 and Atg7 are believed
to be essential for mammalian macroautophagy. Here it is shown, however, that
under certain stress conditions mouse cells lacking Atg5 or Atg7 can still
perform autophagy-mediated protein degradation through an alternative pathway.
Yuya Nishida et al.
doi:10.1038/nature08455
Abstract: http://www.nature.com/nature/journal/v461/n7264/abs/nature08455.html
Article: http://www.nature.com/nature/journal/v461/n7264/full/nature08455.html
Membrane-bound Fas ligand only is essential for Fas-induced apoptosis pp659-663
Fas ligand (FasL) and its receptor Fas are critical for the shutdown of chronic
immune responses and prevention of autoimmunity. FasL function is regulated by
deposition in the plasma membrane and metalloprotease-mediated shedding, but it
is unclear what the respective roles of these secreted and membrane-bound forms
are. Gene-targeted mice that selectively lack either secreted FasL or membrane-
bound FasL are now generated, shedding light on this problem.
Lorraine A. O/' Reilly et al.
doi:10.1038/nature08402
Abstract: http://www.nature.com/nature/journal/v461/n7264/abs/nature08402.html
Article: http://www.nature.com/nature/journal/v461/n7264/full/nature08402.html
Cooperative binding of two acetylation marks on a histone tail by a single
bromodomain pp664-668
The recognition of histone post-translational modifications by effector modules
such as bromodomains is a key step in many chromatin-related processes. Although
effector-mediated recognition of single post-translation modifications is well
characterized, combinatorial readout of histones bearing multiple modifications
is poorly understood. Here, a distinct mechanism of combinatorial readout for
the mouse TAF1 homologue Brdt, a testis-specific member of the BET protein family, is reported.
Jeanne Moriniere et al.
doi:10.1038/nature08397
Abstract: http://www.nature.com/nature/journal/v461/n7264/abs/nature08397.html
Article: http://www.nature.com/nature/journal/v461/n7264/full/nature08397.html
Substrate interactions and promiscuity in a viral DNA packaging motor pp669-673
In several viruses and bacteriophages, DNA transport in processes such as genome
packaging is dependent on a subset of the ASCE superfamily of protein enzymes
consisting of multimeric ringed pumps. Little is known, however, about how these
motors engage their nucleic acid substrates. Here, the genome packaging motor of
the Bacillus subtilis bacteriophage is studied, revealing that the full
mechanochemical cycle of the motor involves two, rather different, phases.
K. Aathavan et al.
doi:10.1038/nature08443
Abstract: http://www.nature.com/nature/journal/v461/n7264/abs/nature08443.html
Article: http://www.nature.com/nature/journal/v461/n7264/full/nature08443.html
A human 5[prime]-tyrosyl DNA phosphodiesterase that repairs topoisomerase-mediated
DNA damage pp674-678
The mechanism of topoisomerase action involves making a transient break in DNA,
which, if it occurs near another DNA lesion, can persist, with the topoisomerase
attached the 3[prime] or 5[prime] end by a phosphotyrosyl bond. If the DNA termini
are not liberated from the topoisomerase, cancer and neurodegenerative disease
may result. A human enzyme that cleaves 3[prime]-phosphotyrosyl bonds has already
been identified; a complementary enzyme that cleaves 5[prime]-phosphotyrosyl
bonds is now reported.
Felipe Cortes Ledesma et al.
doi:10.1038/nature08444
Abstract: http://www.nature.com/nature/journal/v461/n7264/abs/nature08444.html
Article: http://www.nature.com/nature/journal/v461/n7264/full/nature08444.html
----------------------
FUTURES
----------------------
Quality control p686
A palpable hit.
Marissa Lingen
doi:10.1038/461686a
http://www.nature.com/nature/journal/v461/n7264/full/461686a.html
| 《Nature》目录要览 — 2011-04-28出版 |
| 《Nature》目录要览：2011-01-20出版 |
| 《Nature》目录要览：2010-12-23出版 |
| 《Nature》目录要览：2010-12-16出版 |
| 《Nature》目录要览：2010-12-09出版 |
| 《Nature》目录要览：2010-12-02出版 |
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