《Nature》目录要览：2009年9月10日出版
时间：2009-09-11 阅读： 我要评论:
《Nature》目录要览：2009年9月10日出版
封面故事：关于数据共享问题的不同意见
Cover caption
共享数据是好事，但若是共享你自己的数据，事情就会比较复杂。本期Nature上一系列
特写文章对这一有争议的领域进行探讨。Bryn Nelson对关于数据共享方面最佳实践的
意见进行了调查（News Feature p. 160）。在168页，今年5月份在多伦多举行的一个
关于数据发布的大型研讨会的与会者报告了这次会议的气氛。与会者赞成大型基因组和
蛋白组数据集在正式发表前要迅速对外发布，并且同意这一政策应当延伸到其他数据
集，包括化学结构数据、代谢组学数据、以及RNAi和组织库数据等。也是在5月份，由
欧盟资助的CASIMIR项目举行一个会议，讨论小鼠功能基因组学研究中数据和资源共享
的问题（172页）。 这次罗马会议的很多与会者都觉得，有关数据和资源存储的现有政
策应更有效地执行，资助机构、学术刊物和研究人员在共享问题上需要采取协调的政策
和行动。另请参考本期的编者按（135页）和网上相关内容。
关于mRNA降解过程的传统观点被否定（mRNAs lost in translation）
Co-translational mRNA decay in Saccharomyces cerevisiae
一旦一个信使RNA（mRNA）完成其工作，一旦其遗传信息被核糖体转变成一种多肽，它
就会经历一个降解过程。关于这一过程的一个被广泛接受的模型认为，“耗尽的”
mRNA首先在3'-端被脱去腺苷，然后5'-端的“盖子”被去掉，使得该聚合物易受一个从
5'-端到3'-端的核酸外切酶的影响。重要的是，过去人们认为，这一mRNA不再与核糖体
相关，而是存在于所谓的“细胞质处理小体”（ P bodies）中，即细胞质中含有高浓
度RNA处理酶的区域中。一项新的研究表明，这一观点是不准确的。相反，降解是当
mRNA仍然与积极进行翻译活动的核糖体相联系时发生的，而且被束缚在一个不含核糖体
的状态并不是mRNA开始降解的一个先决条件。这种“共翻译降解”可以实现高效解体，
同时让最终的翻译核糖体完成其合成工作。（Article p. 225）
TERT可从线粒体RMRP的RNA部分生成dsRNA（TERT beyond the telomere）
An RNA-dependent RNA polymerase formed by TERT and the RMRP RNA
由RNA调控的一些类型的沉默过程涉及次级siRNA的生成，它们是通过将单链RNA转变成
双链RNA生成的。这个过程是由一个“依赖于RNA的RNA聚合酶”（ RdRP）完成的。现
在，Maida等人发现，TERT（端粒酶的催化亚单元）可从线粒体“RNA处理核糖核酸内切
酶”（RMRP）的RNA部分生成dsRNA——以前的研究表明，线粒体RMRP在“软骨毛发发育
不全”（一种遗传性矮小症）中发生突变。所生成的dsRNA可被核糖核酸内切酶“切片
机”处理成siRNA。这是关于一种哺乳动物RdRP活性的首次报告。越来越多的证据表
明，TERT对细胞生理有所帮助，这种作用独立于其使端粒伸长的能力，而这项新的研究
工作则指出了其中所涉及的机制之一。（Article p. 230）
月球斜长岩几乎有纯净的组成（Pure lunar anorthosite）
The global distribution of pure anorthosite on the Moon
根据对月球斜长岩（英文anorthosite，主要由在月球上居主导地位的斜长石
（plagioclase feldspar）组成的火成岩）样品所做分析，月球高地的浅色壳层被认为
是由斜长石（plagioclase）从一个全球性的岩浆海洋中结晶和浮动形成的。这样一个
壳层的精确形成机制仍然是一个有争议的问题。现在，来自SELENE（日本月球探测器
KAGUYA的主要轨道运行器）的光谱数据，被用来生成关于月壳组成的一个清晰的、具有
高空间分辨率的视图。来自69个不同地点的这些数据显示，月壳中普遍存在几乎纯净的
斜长岩（anorthosite）（含100%的斜长石（plagioclase））。这个结果与以前认为月
球斜长岩中含82%-92%斜长石的估计数字形成鲜明对比，为关于月球岩浆海洋演化的模
型提供了一个有价值的约束条件。（本文中涉及的几个岩石名称都可翻译成斜长石，但
英文名称是有区别的——译者注）（Letter p. 236）
一种新形式的光学存储器方案（Optical slice-and-dice）
Coherent optical pulse sequencer for quantum applications
量子计算机和信息网络将需要一个能够存取数据、相当于电子计算机的随机存取存储器
的存储器。为此，来自堪培拉澳大利亚国立大学的一个小组设计出一种新形式的光学存
储器方案，它允许对所存储的光量子信息进行随机访问。多个光脉冲被存在一个基于铷
原子的相干光学存储器中。这些脉冲可被人为调出、分割和短暂压缩或延伸。虽然迄今
为止实验中所用的都是经典光脉冲，但该方法应可适用于供存储量子信息的一种随机时
间存取存储器的研制。（Letter p. 241）
解决沸石微孔所造成扩散限制的方法（Zeolite catalysis: the thin of it）
Stable single-unit-cell nanosheets of zeolite MFI as active and long-lived
catalysts
沸石（有微孔的铝硅酸盐晶体）被广泛用在工业中，作为具有尺寸和形状选择性的催化
剂。但正是这些使得它们具有催化活性的微孔给它们造成扩散限制。现在，Choi等人发
现，这个问题可通过在有双功能表面活性剂存在时合成沸石来解决。双功能表面活性剂
可以同时引导微孔形成和限制沸石晶体生长成厚度只有一个晶格单位的“纳米层”。这
些结构特征使得超薄沸石对于有机大分子的催化转化具有高度活性；它们还能减小扩散
限制的副作用，正如在甲醇向汽油转化过程中结焦及催化剂失活大大减小所表明的那
样。（Letter p. 246; News & Views）
“大氧化事件”并未导致地球大气氧含量一直增加（The rise and fall of oxygen）
Fluctuations in Precambrian atmospheric oxygenation recorded by chromium
isotopes
地球大气中氧含量的增加被认为是通过两大步骤发生的，但该过程的细节仍然不确定。
Frei等人利用来自条带状含铁构造（它们是以氧化铁形式含有大量氧的沉积岩）稳定铬
同位素，来追踪前寒武纪海洋中六价铬的存在，从而为地球大气-水圈系统的氧生成提
供了一个具有时间分辨率的画面。他们的数据表明，在从距今24.5亿年前到距今22亿年
前氧含量第一次大幅度增加（被称为“大氧化事件”）之前，大气及海洋表面的氧含量
有一个短暂的升高过程。铬在距今18.8亿年的条带状含铁构造中没有被分隔开来，说明
大气中氧含量有所下降。本文作者们提出，“大氧化事件”并没有导致大气中氧含量单
向分段式增加。（Letter p. 250; News & Views）
利基在保持生物多样性中的作用（Biodiversity: niches work）
The importance of niches for the maintenance of species diversity
如果说生物为了生存而永久争斗的话，那么为什么生物群落还如此多样化？对这个问题
的传统回答是存在生态利基——即便是在非常小的尺度上，环境差异也足以允许不同物
种共存。最近，关于生物多样性的“中性理论”提出，这种解释太复杂，物种分布更多
地是由偶然因素造成的。Jonathan Levine 和 Janneke HilleRisLambers通过将实验与
理论相结合的方式对这些思想进行了验证，发现当利基失去时生物多样会下降：至少在
这个回合，传统解释占了上风。（Letter p. 254）
噬蓝藻体中也存在光合体系-I（PSI）（Photosystems at the double）
Photosystem I gene cassettes are present in marine virus genomes
像植物叶绿体一样，海洋蓝细菌的光合作用膜也含有两个光合体系：光合体系-II
（PSII）调控电子从水到质体醌（亦称叶绿醌）的转移，而光合体系-I（PSI）调控电
子从质体蓝素向铁氧化还原蛋白的转移，从而减少以NADPH（还原型辅酶Ⅱ）形式固定
CO2所需能量。核心PSII基因最近在噬蓝藻体（感染蓝细菌的病毒）中被发现，在那里
它们的作用可能是补充宿主的光合作用能力。现在，对来自“Sorcerer II全球海洋取
样考察”项目的元基因组数据和有关病毒生物区系的研究数据所做的一项分析表明，
PSI成分也存在于噬蓝藻体中，也可能具有帮助提高光合作用整体表现的功能。
（Letter p. 258）
关于大脑决策机制的一个新理论（Decisions, decisions）
Changes of mind in decision-making
怎样改变我们的想法？理论神经学家已经建立了一些似乎比较合理的模型，来解释大脑
是怎样根据“吵杂的”、并且经常是含糊的信息来做出一个决定的，但这些模型都假
设，一旦决定已经做出，它就是永久性的。现在，研究人员进行了一系列实验，让实验
对象根据一个吵杂的视觉刺激来将一个手柄向两个位置当中的其中之一移动。他们用这
些实验建立了一个新模型，来解释在我们做出一个决定后我们怎样以及什么时候改变我
们的想法。实验中存在一些少见的情形：实验对象在选择他们答案的过程中便改变了他
们的想法。对这些情形所做分析表明，即便在做出一个决定之后，大脑也会继续处理它
所获得的信息（即信息仍然在处理管道中），要么撤销其当初决定，要么确认其当初决
定。该新理论将犹豫不决和自我纠正的动作引入了决策过程中。（Letter p. 263）
“第二代”测序方法——“外显子组”测序（Targeting the human exome）
Targeted capture and massively parallel sequencing of 12 human exomes
近年来DNA测序成本已大幅度下降，但它们对用来识别罕见和新颖变异体的全基因组测
序来说仍然太高，无法作为常规手段对大量人群采用。现在，Ng等人发现，定向捕捉和
大规模并行测序，对于在不同人类基因组中引起蛋白编码变化的变异体的灵敏的、特异
性的识别来说，可能是一种成本合理的、可重现的和比较稳妥的策略。利用这种“第二
代”测序方法，他们在12个人的“外显子组”（基因组的蛋白编码区）中确定了307个
巨碱基（百万碱基）。用Freeman-Sheldon综合症作为“概念证明”工具发现，引起单
基因疾病的候选基因可通过对少量不相关的、受影响的个体进行“外显子组”测序来识
别。（Letter p. 272）
果蝇对CO2排斥力受到抑制的机制（Fruit flies’ carbon dioxide avoidance
suppressed）
Modification of CO2 avoidance behaviour in Drosophila by inhibitory odorants
果蝇能够本能地避开二氧化碳，比如说由紧张的其他果蝇所产生的二氧化碳，但当二氧
化碳与其他气味剂（如由成熟的水果所产生的气味剂）相结合时，它们又能克服这种先
天排斥力。Stephanie Turner 和Anandasankar Ray报告说，这类能够改变行为的食物
气味剂直接作用于果蝇触角中对二氧化碳敏感的神经元上，而不是像人们所想的那样通
过其他嗅觉通道间接发挥作用。其他天然出现的气味剂也能阻断库蚊对二氧化碳有反应
的神经元的作用。库蚊是西尼罗河病毒及丝虫病的昆虫媒介。鉴于这些昆虫能被人呼出
的二氧化碳所吸引，这些抑制蚊子中对二氧化碳敏感的神经元的抑制剂，有可能帮助寻
找通过阻断这一通道发挥作用的驱蚊剂。（Letter p. 277）
凋亡细胞的“找到我”信号（Apoptosis: how cells become targets）
Nucleotides released by apoptotic cells act as a find-me signal to promote
phagocytic clearance
细胞凋亡几乎在所有组织中都出现，是正常发育和体内平衡的构成部分。不过，即使在
有较高细胞周转率的组织中，凋亡细胞也很少见；这种现象一直被归因于凋亡细胞具有
这样一种能力：它们能够通过“找到我”信号的释放来表示自己的存在，从而招来吞噬
细胞，立即启动清除过程。然而，凋亡细胞所释放的是哪种类型的“找到我”信号以及
这些信号是怎样被吞噬细胞检测到的仍不清楚。在这篇论文中，研究人员发现凋亡细胞
释放ATP 和 UTP，它们对表达P2Y2 ATP/UTP受体的吞噬细胞来说充当一种“找到我”信
号及化学引诱剂。（Letter p. 282; News & Views）
----------------------
NEWS AND VIEWS
----------------------
Sex determination: Birds do it with a Z gene pp177-178
The gene that determines sex in birds has eluded scientists for a decade.
Now this all-important locus is revealed as a gene on the Z chromosome
known for its proclivity for determining sex in all kinds of animals.
Jennifer A. Marshall Graves
doi:10.1038/461177a
http://www.nature.com/nature/journal/v461/n7261/full/461177a.html
Nanotechnology: A gentle jackhammer pp178-179
A futuristic method of data storage depends on the 'write-read' action
of a multitude of tiny silicon tips. The concept of dynamic superlubricity
offers a way to avoid the wear that would otherwise cripple them.
Enrico Gnecco
doi:10.1038/461178a
http://www.nature.com/nature/journal/v461/n7261/full/461178a.html
Early Earth: Oxygen for heavy-metal fans pp179-181
Chromium isotopes provide an eyebrow-raising history of oxygenation of
Earth's atmosphere. Not least, it seems that oxygen might have all but
disappeared half a billion years after its initial rise.
Timothy W. Lyons and Christopher T. Reinhard
doi:10.1038/461179a
http://www.nature.com/nature/journal/v461/n7261/full/461179a.html
50 & 100 years ago p180
doi:10.1038/461180a
http://www.nature.com/nature/journal/v461/n7261/full/461180a.html
Cell biology: Sent by the scent of death pp181-182
Dying cells release 'find-me' factors that attract professional scavenger
cells to engulf and digest them. These cellular invitations to dine can
take unexpected forms.
Christopher Gregory
doi:10.1038/461181a
http://www.nature.com/nature/journal/v461/n7261/full/461181a.html
Materials chemistry: Catalysts made thinner pp182-183
Thinner can be better, at least for the industrially useful catalysts
known as zeolites. A technique that allows single layers of zeolites to
assemble from solution opens up a plethora of practical applications.
Avelino Corma
doi:10.1038/461182a
http://www.nature.com/nature/journal/v461/n7261/full/461182a.html
Developmental biology: Instructions writ in blood pp183-184
It seems that growth factors may instruct blood-cell progenitors to
develop into specific mature cell types, actively determining lineage
choice. But is this reductionist view of cell fate overly simplistic?
Tariq Enver and Sten Eirik W. Jacobsen
doi:10.1038/461183a
http://www.nature.com/nature/journal/v461/n7261/full/461183a.html
----------------------
INSIGHT
----------------------
EDITORIAL
Transcribing the genome p185
Alex Eccleston and Magdalena Skipper
doi:10.1038/461185a
http://www.nature.com/nature/journal/v461/n7261/full/461185a.html
REVIEW ARTICLE
Defining mechanisms that regulate RNA polymerase II transcription in vivo
pp186-192
Nicholas J. Fuda, M. Behfar Ardehali and John T. Lis
doi:10.1038/nature08449
Abstract:
http://www.nature.com/nature/journal/v461/n7261/abs/nature08449.html
Article:
http://www.nature.com/nature/journal/v461/n7261/full/nature08449.html
The logic of chromatin architecture and remodelling at promoters
p193-198
Bradley R. Cairns
doi:10.1038/nature08450
Abstract:
http://www.nature.com/nature/journal/v461/n7261/abs/nature08450.html
Article:
http://www.nature.com/nature/journal/v461/n7261/full/nature08450.html
Genomic views of distant-acting enhancers pp199-205
Axel Visel, Edward M. Rubin and Len A. Pennacchio
doi:10.1038/nature08451
Abstract:
http://www.nature.com/nature/journal/v461/n7261/abs/nature08451.html
Article:
http://www.nature.com/nature/journal/v461/n7261/full/nature08451.html
Implications of chimaeric non-co-linear transcripts pp206-211
Thomas R. Gingeras
doi:10.1038/nature08452
Abstract:
http://www.nature.com/nature/journal/v461/n7261/abs/nature08452.html
Article:
http://www.nature.com/nature/journal/v461/n7261/full/nature08452.html
Chromosome crosstalk in three dimensions pp212-217
Anita Gondor and Rolf Ohlsson
doi:10.1038/nature08453
Abstract:
http://www.nature.com/nature/journal/v461/n7261/abs/nature08453.html
Article:
http://www.nature.com/nature/journal/v461/n7261/full/nature08453.html
Molecular networks as sensors and drivers of common human
diseases pp218-223
Eric E. Schadt
doi:10.1038/nature08454
Abstract:
http://www.nature.com/nature/journal/v461/n7261/abs/nature08454.html
Article:
http://www.nature.com/nature/journal/v461/n7261/full/nature08454.html
----------------------
ARTICLES
----------------------
Co-translational mRNA decay in Saccharomyces cerevisiae pp225-229
The levels of messenger RNA are determined by the rates of RNA decay and
transcription, but although the details of transcriptional regulation are
increasingly understood, the mechanism(s) controlling mRNA decay remain
unclear.
In yeast, it is hypothesized that ribosomes must be removed from mRNA before
transcripts are destroyed. However, here it is shown that decay takes place
while mRNAs are associated with actively translating ribosomes, allowing the
last translocating ribosome to complete translation.
Wenqian Hu et al.
doi:10.1038/nature08265
Abstract:
http://www.nature.com/nature/journal/v461/n7261/abs/nature08265.html
Article:
http://www.nature.com/nature/journal/v461/n7261/full/nature08265.html
An RNA-dependent RNA polymerase formed by TERT and the RMRP RNA pp230-235
Accumulating evidence suggests that the human telomerase reverse
transcriptase
catalytic subunit (TERT) has a role in cell physiology independent to that
of
elongating telomeres. Here it is shown to interact with RMRP, a gene that is
mutated in the syndrome cartilage-hair hypoplasia, to form a distinct
ribonucleoprotein complex that has RNA-dependent RNA polymerase (RdRP)
activity
and produces double-stranded RNAs that can be processed into small
interfering RNAs.
Yoshiko Maida et al.
doi:10.1038/nature08283
Abstract:
http://www.nature.com/nature/journal/v461/n7261/abs/nature08283.html
Article:
http://www.nature.com/nature/journal/v461/n7261/full/nature08283.html
----------------------
LETTERS
----------------------
The global distribution of pure anorthosite on the Moon pp236-240
It has long been thought that the lunar highland crust was formed by the
crystallization and floatation of plagioclase from a global magma ocean,
but the exact mechanism by which such a crust formed remains debated. Data
from the Japanese SELENE spacecraft are now used to produce a clear and high
spatial resolution view of the composition of the lunar crust. The existence
of widely distributed crustal rocks with compositions approaching 100 per
cent (by volume) plagioclase is revealed.
Makiko Ohtake et al.
doi:10.1038/nature08317
Abstract:
http://www.nature.com/nature/journal/v461/n7261/abs/nature08317.html
Article:
http://www.nature.com/nature/journal/v461/n7261/full/nature08317.html
Coherent optical pulse sequencer for quantum applications pp241-245
Precise and arbitrary control of an optical field that preserves optical
coherence is an important requisite for many proposed photonic technologies.
Here, a coherent optical memory based on photon echoes induced through
controlled
reversible inhomogeneous broadening is presented. The scheme allows storage
of
multiple pulses of light which can be arbitrarily recalled, time-stretched
or split.
Mahdi Hosseini et al.
doi:10.1038/nature08325
Abstract:
http://www.nature.com/nature/journal/v461/n7261/abs/nature08325.html
Article:
http://www.nature.com/nature/journal/v461/n7261/full/nature08325.html
Stable single-unit-cell nanosheets of zeolite MFI as active and long-lived
catalysts pp246-249
Zeolites [mdash] microporous crystalline aluminosilicates [mdash] are
widely
used in industry as size- and shape-selective catalysts, but the micropores
that enable this catalytic activity also cause diffusion limitations that
adversely affect it. This can be overcome by reducing the thickness of the
zeolite crystals and thus improving molecular diffusion. Here it is shown
that bifunctional surfactants can direct the formation of zeolite structures
that are only one unit cell thick.
Minkee Choi et al.
doi:10.1038/nature08288
Abstract:
http://www.nature.com/nature/journal/v461/n7261/abs/nature08288.html
Article:
http://www.nature.com/nature/journal/v461/n7261/full/nature08288.html
Fluctuations in Precambrian atmospheric oxygenation recorded by chromium
isotopes pp250-253
It is thought that oxygenation of the Earth's atmosphere occurred in two
broad
steps, but details of the evolution of atmospheric oxygenation remain
uncertain.
Chromium (Cr) stable isotopes from banded iron formations are now used to
track
the presence of Cr(VI) in Precambrian oceans, providing a time-resolved
picture
of the oxygenation history of the Earth's atmosphere-hydrosphere system.
Robert Frei, Claudio Gaucher, Simon W. Poulton and Don E. Canfield
doi:10.1038/nature08266
Abstract:
http://www.nature.com/nature/journal/v461/n7261/abs/nature08266.html
Article:
http://www.nature.com/nature/journal/v461/n7261/full/nature08266.html
The importance of niches for the maintenance of species
diversity pp254-257
If organisms are involved in a perpetual struggle for existence, how is it
that
communities are so diverse? The traditional answer is the ecological niche
but
this has recently been challenged by the neutral theory of biodiversity,
which
explains coexistence with the equivalence of competitors. Here, theory and
experimentation are integrated in order to explore this problem; the results
show that diversity declines when niches are removed.
Jonathan M. Levine and Janneke HilleRisLambers
doi:10.1038/nature08251
Abstract:
http://www.nature.com/nature/journal/v461/n7261/abs/nature08251.html
Article:
http://www.nature.com/nature/journal/v461/n7261/full/nature08251.html
Photosystem I gene cassettes are present in marine virus
genomes pp258-262
Cyanobacteria are important contributors to photosynthetic productivity in
the open oceans. Functional photosystem II components are known to be
encoded
in cyanophage genomes and are suggested to provide a fitness advantage to
the
virus by boosting host performance. It is now shown that photosystem I
components can also be detected in cyanophages.
Itai Sharon et al.
doi:10.1038/nature08284
Abstract:
http://www.nature.com/nature/journal/v461/n7261/abs/nature08284.html
Article:
http://www.nature.com/nature/journal/v461/n7261/full/nature08284.html
Changes of mind in decision-making pp263-266
How do we change our minds? Here, subjects were asked to make decisions
about
a noisy visual stimulus, which they indicated by moving a handle. By
following
hand trajectories, it was possible to determine the rare occasions when
subjects
changed their minds halfway through a trial. The authors extend a model
developed
to account for the timing and accuracy of the initial decision to explain
these
subsequent changes of mind.
Arbora Resulaj, Roozbeh Kiani, Daniel M. Wolpert and Michael N. Shadlen
doi:10.1038/nature08275
Abstract:
http://www.nature.com/nature/journal/v461/n7261/abs/nature08275.html
Article:
http://www.nature.com/nature/journal/v461/n7261/full/nature08275.html
The avian Z-linked gene DMRT1 is required for male sex determination in the
chicken pp267-271
Although sex determination in birds, as in mammals, is chromosomally based,
its mechanism has been a long-standing mystery. In birds, the homogametic
sex
is male (ZZ) and the heterogametic sex is female (ZW); one hypothesis is
that
two doses of a Z-linked gene are required for male development. Here it is
shown that reducing expression of the conserved Z-linked gene DMRT1
feminizes
the embryonic gonads in genetically male (ZZ) chicken embryos.
Craig A. Smith et al.
doi:10.1038/nature08298
Abstract:
http://www.nature.com/nature/journal/v461/n7261/abs/nature08298.html
Article:
http://www.nature.com/nature/journal/v461/n7261/full/nature08298.html
Targeted capture and massively parallel sequencing of 12 human
exomes pp272-276
Although DNA sequencing costs have fallen dramatically, they are still too
high for whole genome sequencing to be used to routinely identify rare and
novel variants in large cohorts. The targeted capture and massively parallel
sequencing of the exomes of 12 humans is now reported. Freeman-Sheldon
syndrome
is used as a proof-of-concept that candidate genes for monogenic disorders
can
be identified by exome sequencing of a small number of unrelated, affected
individuals.
Sarah B. Ng et al.
doi:10.1038/nature08250
Abstract:
http://www.nature.com/nature/journal/v461/n7261/abs/nature08250.html
Article:
http://www.nature.com/nature/journal/v461/n7261/full/nature08250.html
Modification of CO2 avoidance behaviour in Drosophila by inhibitory
odorants
pp277-281
Fruitflies instinctively avoid CO2, for example that produced by stressed
fellow
flies, but they overcome this avoidance response in some environments that
contain CO2, such as ripening fruits. Here, a new class of odorants present
in
food is identified that directly inhibit CO2-sensitive neurons in the
antenna -
not, as one would expect, indirectly via other olfactory pathways.
Stephanie Lynn Turner and Anandasankar Ray
doi:10.1038/nature08295
Abstract:
http://www.nature.com/nature/journal/v461/n7261/abs/nature08295.html
Article:
http://www.nature.com/nature/journal/v461/n7261/full/nature08295.html
Nucleotides released by apoptotic cells act as a find-me signal to promote
phagocytic clearance pp282-286
The efficient removal of apoptotic cells in vivo is thought to be due to the
release of 'find-me' signals by apoptotic cells that recruit motile
phagocytes.
Here, the caspase-dependent release of ATP and UTP during the early stages
of
apoptosis is demonstrated. ATP and UTP are found to act as chemoattractants
in
a process mediated through the ATP/UTP receptor P2Y2, which is present on
monocytes and macrophages.
Michael R. Elliott et al.
doi:10.1038/nature08296
Abstract:
http://www.nature.com/nature/journal/v461/n7261/abs/nature08296.html
Article:
http://www.nature.com/nature/journal/v461/n7261/full/nature08296.html
ErbB2 resembles an autoinhibited invertebrate epidermal growth factor
receptor
pp287-291
The tyrosine kinase receptor ErbB2 has been implicated in cancer,
particularly
breast cancer. It has been suggested that its oncogenic signalling
properties
result from the absence of a key 'tether' in the extracellular region that
autoinhibits other human ErbB receptors. ErbB2 is now shown to be the
closest
structural relative of the dEGFR receptor in Drosophila; although dEGFR also
lacks a tether, a distinct set of autoinhibitory interactions keep it
inactive.
Diego Alvarado, Daryl E. Klein and Mark A. Lemmon
doi:10.1038/nature08297
Abstract:
http://www.nature.com/nature/journal/v461/n7261/abs/nature08297.html
Article:
http://www.nature.com/nature/journal/v461/n7261/full/nature08297.html
Structure of the BK potassium channel in a lipid membrane from electron
cryomicroscopy pp292-295
Electron cryomicroscopy (cryo-EM) is an increasingly powerful method for
looking at the structures of large soluble proteins that does not require
crystallization of the proteins. Here, the first single-particle cryo-EM
study
of a membrane protein is reported- the human large-conductance calcium- and
voltage-activated potassium channel (BK) - in a lipid environment.
Liguo Wang and Fred J. Sigworth
doi:10.1038/nature08291
Abstract:
http://www.nature.com/nature/journal/v461/n7261/abs/nature08291.html
Article:
http://www.nature.com/nature/journal/v461/n7261/full/nature08291.html
Cover caption
共享数据是好事，但若是共享你自己的数据，事情就会比较复杂。本期Nature上一系列
特写文章对这一有争议的领域进行探讨。Bryn Nelson对关于数据共享方面最佳实践的
意见进行了调查（News Feature p. 160）。在168页，今年5月份在多伦多举行的一个
关于数据发布的大型研讨会的与会者报告了这次会议的气氛。与会者赞成大型基因组和
蛋白组数据集在正式发表前要迅速对外发布，并且同意这一政策应当延伸到其他数据
集，包括化学结构数据、代谢组学数据、以及RNAi和组织库数据等。也是在5月份，由
欧盟资助的CASIMIR项目举行一个会议，讨论小鼠功能基因组学研究中数据和资源共享
的问题（172页）。 这次罗马会议的很多与会者都觉得，有关数据和资源存储的现有政
策应更有效地执行，资助机构、学术刊物和研究人员在共享问题上需要采取协调的政策
和行动。另请参考本期的编者按（135页）和网上相关内容。
关于mRNA降解过程的传统观点被否定（mRNAs lost in translation）
Co-translational mRNA decay in Saccharomyces cerevisiae
一旦一个信使RNA（mRNA）完成其工作，一旦其遗传信息被核糖体转变成一种多肽，它
就会经历一个降解过程。关于这一过程的一个被广泛接受的模型认为，“耗尽的”
mRNA首先在3'-端被脱去腺苷，然后5'-端的“盖子”被去掉，使得该聚合物易受一个从
5'-端到3'-端的核酸外切酶的影响。重要的是，过去人们认为，这一mRNA不再与核糖体
相关，而是存在于所谓的“细胞质处理小体”（ P bodies）中，即细胞质中含有高浓
度RNA处理酶的区域中。一项新的研究表明，这一观点是不准确的。相反，降解是当
mRNA仍然与积极进行翻译活动的核糖体相联系时发生的，而且被束缚在一个不含核糖体
的状态并不是mRNA开始降解的一个先决条件。这种“共翻译降解”可以实现高效解体，
同时让最终的翻译核糖体完成其合成工作。（Article p. 225）
TERT可从线粒体RMRP的RNA部分生成dsRNA（TERT beyond the telomere）
An RNA-dependent RNA polymerase formed by TERT and the RMRP RNA
由RNA调控的一些类型的沉默过程涉及次级siRNA的生成，它们是通过将单链RNA转变成
双链RNA生成的。这个过程是由一个“依赖于RNA的RNA聚合酶”（ RdRP）完成的。现
在，Maida等人发现，TERT（端粒酶的催化亚单元）可从线粒体“RNA处理核糖核酸内切
酶”（RMRP）的RNA部分生成dsRNA——以前的研究表明，线粒体RMRP在“软骨毛发发育
不全”（一种遗传性矮小症）中发生突变。所生成的dsRNA可被核糖核酸内切酶“切片
机”处理成siRNA。这是关于一种哺乳动物RdRP活性的首次报告。越来越多的证据表
明，TERT对细胞生理有所帮助，这种作用独立于其使端粒伸长的能力，而这项新的研究
工作则指出了其中所涉及的机制之一。（Article p. 230）
月球斜长岩几乎有纯净的组成（Pure lunar anorthosite）
The global distribution of pure anorthosite on the Moon
根据对月球斜长岩（英文anorthosite，主要由在月球上居主导地位的斜长石
（plagioclase feldspar）组成的火成岩）样品所做分析，月球高地的浅色壳层被认为
是由斜长石（plagioclase）从一个全球性的岩浆海洋中结晶和浮动形成的。这样一个
壳层的精确形成机制仍然是一个有争议的问题。现在，来自SELENE（日本月球探测器
KAGUYA的主要轨道运行器）的光谱数据，被用来生成关于月壳组成的一个清晰的、具有
高空间分辨率的视图。来自69个不同地点的这些数据显示，月壳中普遍存在几乎纯净的
斜长岩（anorthosite）（含100%的斜长石（plagioclase））。这个结果与以前认为月
球斜长岩中含82%-92%斜长石的估计数字形成鲜明对比，为关于月球岩浆海洋演化的模
型提供了一个有价值的约束条件。（本文中涉及的几个岩石名称都可翻译成斜长石，但
英文名称是有区别的——译者注）（Letter p. 236）
一种新形式的光学存储器方案（Optical slice-and-dice）
Coherent optical pulse sequencer for quantum applications
量子计算机和信息网络将需要一个能够存取数据、相当于电子计算机的随机存取存储器
的存储器。为此，来自堪培拉澳大利亚国立大学的一个小组设计出一种新形式的光学存
储器方案，它允许对所存储的光量子信息进行随机访问。多个光脉冲被存在一个基于铷
原子的相干光学存储器中。这些脉冲可被人为调出、分割和短暂压缩或延伸。虽然迄今
为止实验中所用的都是经典光脉冲，但该方法应可适用于供存储量子信息的一种随机时
间存取存储器的研制。（Letter p. 241）
解决沸石微孔所造成扩散限制的方法（Zeolite catalysis: the thin of it）
Stable single-unit-cell nanosheets of zeolite MFI as active and long-lived
catalysts
沸石（有微孔的铝硅酸盐晶体）被广泛用在工业中，作为具有尺寸和形状选择性的催化
剂。但正是这些使得它们具有催化活性的微孔给它们造成扩散限制。现在，Choi等人发
现，这个问题可通过在有双功能表面活性剂存在时合成沸石来解决。双功能表面活性剂
可以同时引导微孔形成和限制沸石晶体生长成厚度只有一个晶格单位的“纳米层”。这
些结构特征使得超薄沸石对于有机大分子的催化转化具有高度活性；它们还能减小扩散
限制的副作用，正如在甲醇向汽油转化过程中结焦及催化剂失活大大减小所表明的那
样。（Letter p. 246; News & Views）
“大氧化事件”并未导致地球大气氧含量一直增加（The rise and fall of oxygen）
Fluctuations in Precambrian atmospheric oxygenation recorded by chromium
isotopes
地球大气中氧含量的增加被认为是通过两大步骤发生的，但该过程的细节仍然不确定。
Frei等人利用来自条带状含铁构造（它们是以氧化铁形式含有大量氧的沉积岩）稳定铬
同位素，来追踪前寒武纪海洋中六价铬的存在，从而为地球大气-水圈系统的氧生成提
供了一个具有时间分辨率的画面。他们的数据表明，在从距今24.5亿年前到距今22亿年
前氧含量第一次大幅度增加（被称为“大氧化事件”）之前，大气及海洋表面的氧含量
有一个短暂的升高过程。铬在距今18.8亿年的条带状含铁构造中没有被分隔开来，说明
大气中氧含量有所下降。本文作者们提出，“大氧化事件”并没有导致大气中氧含量单
向分段式增加。（Letter p. 250; News & Views）
利基在保持生物多样性中的作用（Biodiversity: niches work）
The importance of niches for the maintenance of species diversity
如果说生物为了生存而永久争斗的话，那么为什么生物群落还如此多样化？对这个问题
的传统回答是存在生态利基——即便是在非常小的尺度上，环境差异也足以允许不同物
种共存。最近，关于生物多样性的“中性理论”提出，这种解释太复杂，物种分布更多
地是由偶然因素造成的。Jonathan Levine 和 Janneke HilleRisLambers通过将实验与
理论相结合的方式对这些思想进行了验证，发现当利基失去时生物多样会下降：至少在
这个回合，传统解释占了上风。（Letter p. 254）
噬蓝藻体中也存在光合体系-I（PSI）（Photosystems at the double）
Photosystem I gene cassettes are present in marine virus genomes
像植物叶绿体一样，海洋蓝细菌的光合作用膜也含有两个光合体系：光合体系-II
（PSII）调控电子从水到质体醌（亦称叶绿醌）的转移，而光合体系-I（PSI）调控电
子从质体蓝素向铁氧化还原蛋白的转移，从而减少以NADPH（还原型辅酶Ⅱ）形式固定
CO2所需能量。核心PSII基因最近在噬蓝藻体（感染蓝细菌的病毒）中被发现，在那里
它们的作用可能是补充宿主的光合作用能力。现在，对来自“Sorcerer II全球海洋取
样考察”项目的元基因组数据和有关病毒生物区系的研究数据所做的一项分析表明，
PSI成分也存在于噬蓝藻体中，也可能具有帮助提高光合作用整体表现的功能。
（Letter p. 258）
关于大脑决策机制的一个新理论（Decisions, decisions）
Changes of mind in decision-making
怎样改变我们的想法？理论神经学家已经建立了一些似乎比较合理的模型，来解释大脑
是怎样根据“吵杂的”、并且经常是含糊的信息来做出一个决定的，但这些模型都假
设，一旦决定已经做出，它就是永久性的。现在，研究人员进行了一系列实验，让实验
对象根据一个吵杂的视觉刺激来将一个手柄向两个位置当中的其中之一移动。他们用这
些实验建立了一个新模型，来解释在我们做出一个决定后我们怎样以及什么时候改变我
们的想法。实验中存在一些少见的情形：实验对象在选择他们答案的过程中便改变了他
们的想法。对这些情形所做分析表明，即便在做出一个决定之后，大脑也会继续处理它
所获得的信息（即信息仍然在处理管道中），要么撤销其当初决定，要么确认其当初决
定。该新理论将犹豫不决和自我纠正的动作引入了决策过程中。（Letter p. 263）
“第二代”测序方法——“外显子组”测序（Targeting the human exome）
Targeted capture and massively parallel sequencing of 12 human exomes
近年来DNA测序成本已大幅度下降，但它们对用来识别罕见和新颖变异体的全基因组测
序来说仍然太高，无法作为常规手段对大量人群采用。现在，Ng等人发现，定向捕捉和
大规模并行测序，对于在不同人类基因组中引起蛋白编码变化的变异体的灵敏的、特异
性的识别来说，可能是一种成本合理的、可重现的和比较稳妥的策略。利用这种“第二
代”测序方法，他们在12个人的“外显子组”（基因组的蛋白编码区）中确定了307个
巨碱基（百万碱基）。用Freeman-Sheldon综合症作为“概念证明”工具发现，引起单
基因疾病的候选基因可通过对少量不相关的、受影响的个体进行“外显子组”测序来识
别。（Letter p. 272）
果蝇对CO2排斥力受到抑制的机制（Fruit flies’ carbon dioxide avoidance
suppressed）
Modification of CO2 avoidance behaviour in Drosophila by inhibitory odorants
果蝇能够本能地避开二氧化碳，比如说由紧张的其他果蝇所产生的二氧化碳，但当二氧
化碳与其他气味剂（如由成熟的水果所产生的气味剂）相结合时，它们又能克服这种先
天排斥力。Stephanie Turner 和Anandasankar Ray报告说，这类能够改变行为的食物
气味剂直接作用于果蝇触角中对二氧化碳敏感的神经元上，而不是像人们所想的那样通
过其他嗅觉通道间接发挥作用。其他天然出现的气味剂也能阻断库蚊对二氧化碳有反应
的神经元的作用。库蚊是西尼罗河病毒及丝虫病的昆虫媒介。鉴于这些昆虫能被人呼出
的二氧化碳所吸引，这些抑制蚊子中对二氧化碳敏感的神经元的抑制剂，有可能帮助寻
找通过阻断这一通道发挥作用的驱蚊剂。（Letter p. 277）
凋亡细胞的“找到我”信号（Apoptosis: how cells become targets）
Nucleotides released by apoptotic cells act as a find-me signal to promote
phagocytic clearance
细胞凋亡几乎在所有组织中都出现，是正常发育和体内平衡的构成部分。不过，即使在
有较高细胞周转率的组织中，凋亡细胞也很少见；这种现象一直被归因于凋亡细胞具有
这样一种能力：它们能够通过“找到我”信号的释放来表示自己的存在，从而招来吞噬
细胞，立即启动清除过程。然而，凋亡细胞所释放的是哪种类型的“找到我”信号以及
这些信号是怎样被吞噬细胞检测到的仍不清楚。在这篇论文中，研究人员发现凋亡细胞
释放ATP 和 UTP，它们对表达P2Y2 ATP/UTP受体的吞噬细胞来说充当一种“找到我”信
号及化学引诱剂。（Letter p. 282; News & Views）
----------------------
NEWS AND VIEWS
----------------------
Sex determination: Birds do it with a Z gene pp177-178
The gene that determines sex in birds has eluded scientists for a decade.
Now this all-important locus is revealed as a gene on the Z chromosome
known for its proclivity for determining sex in all kinds of animals.
Jennifer A. Marshall Graves
doi:10.1038/461177a
http://www.nature.com/nature/journal/v461/n7261/full/461177a.html
Nanotechnology: A gentle jackhammer pp178-179
A futuristic method of data storage depends on the 'write-read' action
of a multitude of tiny silicon tips. The concept of dynamic superlubricity
offers a way to avoid the wear that would otherwise cripple them.
Enrico Gnecco
doi:10.1038/461178a
http://www.nature.com/nature/journal/v461/n7261/full/461178a.html
Early Earth: Oxygen for heavy-metal fans pp179-181
Chromium isotopes provide an eyebrow-raising history of oxygenation of
Earth's atmosphere. Not least, it seems that oxygen might have all but
disappeared half a billion years after its initial rise.
Timothy W. Lyons and Christopher T. Reinhard
doi:10.1038/461179a
http://www.nature.com/nature/journal/v461/n7261/full/461179a.html
50 & 100 years ago p180
doi:10.1038/461180a
http://www.nature.com/nature/journal/v461/n7261/full/461180a.html
Cell biology: Sent by the scent of death pp181-182
Dying cells release 'find-me' factors that attract professional scavenger
cells to engulf and digest them. These cellular invitations to dine can
take unexpected forms.
Christopher Gregory
doi:10.1038/461181a
http://www.nature.com/nature/journal/v461/n7261/full/461181a.html
Materials chemistry: Catalysts made thinner pp182-183
Thinner can be better, at least for the industrially useful catalysts
known as zeolites. A technique that allows single layers of zeolites to
assemble from solution opens up a plethora of practical applications.
Avelino Corma
doi:10.1038/461182a
http://www.nature.com/nature/journal/v461/n7261/full/461182a.html
Developmental biology: Instructions writ in blood pp183-184
It seems that growth factors may instruct blood-cell progenitors to
develop into specific mature cell types, actively determining lineage
choice. But is this reductionist view of cell fate overly simplistic?
Tariq Enver and Sten Eirik W. Jacobsen
doi:10.1038/461183a
http://www.nature.com/nature/journal/v461/n7261/full/461183a.html
----------------------
INSIGHT
----------------------
EDITORIAL
Transcribing the genome p185
Alex Eccleston and Magdalena Skipper
doi:10.1038/461185a
http://www.nature.com/nature/journal/v461/n7261/full/461185a.html
REVIEW ARTICLE
Defining mechanisms that regulate RNA polymerase II transcription in vivo
pp186-192
Nicholas J. Fuda, M. Behfar Ardehali and John T. Lis
doi:10.1038/nature08449
Abstract:
http://www.nature.com/nature/journal/v461/n7261/abs/nature08449.html
Article:
http://www.nature.com/nature/journal/v461/n7261/full/nature08449.html
The logic of chromatin architecture and remodelling at promoters
p193-198
Bradley R. Cairns
doi:10.1038/nature08450
Abstract:
http://www.nature.com/nature/journal/v461/n7261/abs/nature08450.html
Article:
http://www.nature.com/nature/journal/v461/n7261/full/nature08450.html
Genomic views of distant-acting enhancers pp199-205
Axel Visel, Edward M. Rubin and Len A. Pennacchio
doi:10.1038/nature08451
Abstract:
http://www.nature.com/nature/journal/v461/n7261/abs/nature08451.html
Article:
http://www.nature.com/nature/journal/v461/n7261/full/nature08451.html
Implications of chimaeric non-co-linear transcripts pp206-211
Thomas R. Gingeras
doi:10.1038/nature08452
Abstract:
http://www.nature.com/nature/journal/v461/n7261/abs/nature08452.html
Article:
http://www.nature.com/nature/journal/v461/n7261/full/nature08452.html
Chromosome crosstalk in three dimensions pp212-217
Anita Gondor and Rolf Ohlsson
doi:10.1038/nature08453
Abstract:
http://www.nature.com/nature/journal/v461/n7261/abs/nature08453.html
Article:
http://www.nature.com/nature/journal/v461/n7261/full/nature08453.html
Molecular networks as sensors and drivers of common human
diseases pp218-223
Eric E. Schadt
doi:10.1038/nature08454
Abstract:
http://www.nature.com/nature/journal/v461/n7261/abs/nature08454.html
Article:
http://www.nature.com/nature/journal/v461/n7261/full/nature08454.html
----------------------
ARTICLES
----------------------
Co-translational mRNA decay in Saccharomyces cerevisiae pp225-229
The levels of messenger RNA are determined by the rates of RNA decay and
transcription, but although the details of transcriptional regulation are
increasingly understood, the mechanism(s) controlling mRNA decay remain
unclear.
In yeast, it is hypothesized that ribosomes must be removed from mRNA before
transcripts are destroyed. However, here it is shown that decay takes place
while mRNAs are associated with actively translating ribosomes, allowing the
last translocating ribosome to complete translation.
Wenqian Hu et al.
doi:10.1038/nature08265
Abstract:
http://www.nature.com/nature/journal/v461/n7261/abs/nature08265.html
Article:
http://www.nature.com/nature/journal/v461/n7261/full/nature08265.html
An RNA-dependent RNA polymerase formed by TERT and the RMRP RNA pp230-235
Accumulating evidence suggests that the human telomerase reverse
transcriptase
catalytic subunit (TERT) has a role in cell physiology independent to that
of
elongating telomeres. Here it is shown to interact with RMRP, a gene that is
mutated in the syndrome cartilage-hair hypoplasia, to form a distinct
ribonucleoprotein complex that has RNA-dependent RNA polymerase (RdRP)
activity
and produces double-stranded RNAs that can be processed into small
interfering RNAs.
Yoshiko Maida et al.
doi:10.1038/nature08283
Abstract:
http://www.nature.com/nature/journal/v461/n7261/abs/nature08283.html
Article:
http://www.nature.com/nature/journal/v461/n7261/full/nature08283.html
----------------------
LETTERS
----------------------
The global distribution of pure anorthosite on the Moon pp236-240
It has long been thought that the lunar highland crust was formed by the
crystallization and floatation of plagioclase from a global magma ocean,
but the exact mechanism by which such a crust formed remains debated. Data
from the Japanese SELENE spacecraft are now used to produce a clear and high
spatial resolution view of the composition of the lunar crust. The existence
of widely distributed crustal rocks with compositions approaching 100 per
cent (by volume) plagioclase is revealed.
Makiko Ohtake et al.
doi:10.1038/nature08317
Abstract:
http://www.nature.com/nature/journal/v461/n7261/abs/nature08317.html
Article:
http://www.nature.com/nature/journal/v461/n7261/full/nature08317.html
Coherent optical pulse sequencer for quantum applications pp241-245
Precise and arbitrary control of an optical field that preserves optical
coherence is an important requisite for many proposed photonic technologies.
Here, a coherent optical memory based on photon echoes induced through
controlled
reversible inhomogeneous broadening is presented. The scheme allows storage
of
multiple pulses of light which can be arbitrarily recalled, time-stretched
or split.
Mahdi Hosseini et al.
doi:10.1038/nature08325
Abstract:
http://www.nature.com/nature/journal/v461/n7261/abs/nature08325.html
Article:
http://www.nature.com/nature/journal/v461/n7261/full/nature08325.html
Stable single-unit-cell nanosheets of zeolite MFI as active and long-lived
catalysts pp246-249
Zeolites [mdash] microporous crystalline aluminosilicates [mdash] are
widely
used in industry as size- and shape-selective catalysts, but the micropores
that enable this catalytic activity also cause diffusion limitations that
adversely affect it. This can be overcome by reducing the thickness of the
zeolite crystals and thus improving molecular diffusion. Here it is shown
that bifunctional surfactants can direct the formation of zeolite structures
that are only one unit cell thick.
Minkee Choi et al.
doi:10.1038/nature08288
Abstract:
http://www.nature.com/nature/journal/v461/n7261/abs/nature08288.html
Article:
http://www.nature.com/nature/journal/v461/n7261/full/nature08288.html
Fluctuations in Precambrian atmospheric oxygenation recorded by chromium
isotopes pp250-253
It is thought that oxygenation of the Earth's atmosphere occurred in two
broad
steps, but details of the evolution of atmospheric oxygenation remain
uncertain.
Chromium (Cr) stable isotopes from banded iron formations are now used to
track
the presence of Cr(VI) in Precambrian oceans, providing a time-resolved
picture
of the oxygenation history of the Earth's atmosphere-hydrosphere system.
Robert Frei, Claudio Gaucher, Simon W. Poulton and Don E. Canfield
doi:10.1038/nature08266
Abstract:
http://www.nature.com/nature/journal/v461/n7261/abs/nature08266.html
Article:
http://www.nature.com/nature/journal/v461/n7261/full/nature08266.html
The importance of niches for the maintenance of species
diversity pp254-257
If organisms are involved in a perpetual struggle for existence, how is it
that
communities are so diverse? The traditional answer is the ecological niche
but
this has recently been challenged by the neutral theory of biodiversity,
which
explains coexistence with the equivalence of competitors. Here, theory and
experimentation are integrated in order to explore this problem; the results
show that diversity declines when niches are removed.
Jonathan M. Levine and Janneke HilleRisLambers
doi:10.1038/nature08251
Abstract:
http://www.nature.com/nature/journal/v461/n7261/abs/nature08251.html
Article:
http://www.nature.com/nature/journal/v461/n7261/full/nature08251.html
Photosystem I gene cassettes are present in marine virus
genomes pp258-262
Cyanobacteria are important contributors to photosynthetic productivity in
the open oceans. Functional photosystem II components are known to be
encoded
in cyanophage genomes and are suggested to provide a fitness advantage to
the
virus by boosting host performance. It is now shown that photosystem I
components can also be detected in cyanophages.
Itai Sharon et al.
doi:10.1038/nature08284
Abstract:
http://www.nature.com/nature/journal/v461/n7261/abs/nature08284.html
Article:
http://www.nature.com/nature/journal/v461/n7261/full/nature08284.html
Changes of mind in decision-making pp263-266
How do we change our minds? Here, subjects were asked to make decisions
about
a noisy visual stimulus, which they indicated by moving a handle. By
following
hand trajectories, it was possible to determine the rare occasions when
subjects
changed their minds halfway through a trial. The authors extend a model
developed
to account for the timing and accuracy of the initial decision to explain
these
subsequent changes of mind.
Arbora Resulaj, Roozbeh Kiani, Daniel M. Wolpert and Michael N. Shadlen
doi:10.1038/nature08275
Abstract:
http://www.nature.com/nature/journal/v461/n7261/abs/nature08275.html
Article:
http://www.nature.com/nature/journal/v461/n7261/full/nature08275.html
The avian Z-linked gene DMRT1 is required for male sex determination in the
chicken pp267-271
Although sex determination in birds, as in mammals, is chromosomally based,
its mechanism has been a long-standing mystery. In birds, the homogametic
sex
is male (ZZ) and the heterogametic sex is female (ZW); one hypothesis is
that
two doses of a Z-linked gene are required for male development. Here it is
shown that reducing expression of the conserved Z-linked gene DMRT1
feminizes
the embryonic gonads in genetically male (ZZ) chicken embryos.
Craig A. Smith et al.
doi:10.1038/nature08298
Abstract:
http://www.nature.com/nature/journal/v461/n7261/abs/nature08298.html
Article:
http://www.nature.com/nature/journal/v461/n7261/full/nature08298.html
Targeted capture and massively parallel sequencing of 12 human
exomes pp272-276
Although DNA sequencing costs have fallen dramatically, they are still too
high for whole genome sequencing to be used to routinely identify rare and
novel variants in large cohorts. The targeted capture and massively parallel
sequencing of the exomes of 12 humans is now reported. Freeman-Sheldon
syndrome
is used as a proof-of-concept that candidate genes for monogenic disorders
can
be identified by exome sequencing of a small number of unrelated, affected
individuals.
Sarah B. Ng et al.
doi:10.1038/nature08250
Abstract:
http://www.nature.com/nature/journal/v461/n7261/abs/nature08250.html
Article:
http://www.nature.com/nature/journal/v461/n7261/full/nature08250.html
Modification of CO2 avoidance behaviour in Drosophila by inhibitory
odorants
pp277-281
Fruitflies instinctively avoid CO2, for example that produced by stressed
fellow
flies, but they overcome this avoidance response in some environments that
contain CO2, such as ripening fruits. Here, a new class of odorants present
in
food is identified that directly inhibit CO2-sensitive neurons in the
antenna -
not, as one would expect, indirectly via other olfactory pathways.
Stephanie Lynn Turner and Anandasankar Ray
doi:10.1038/nature08295
Abstract:
http://www.nature.com/nature/journal/v461/n7261/abs/nature08295.html
Article:
http://www.nature.com/nature/journal/v461/n7261/full/nature08295.html
Nucleotides released by apoptotic cells act as a find-me signal to promote
phagocytic clearance pp282-286
The efficient removal of apoptotic cells in vivo is thought to be due to the
release of 'find-me' signals by apoptotic cells that recruit motile
phagocytes.
Here, the caspase-dependent release of ATP and UTP during the early stages
of
apoptosis is demonstrated. ATP and UTP are found to act as chemoattractants
in
a process mediated through the ATP/UTP receptor P2Y2, which is present on
monocytes and macrophages.
Michael R. Elliott et al.
doi:10.1038/nature08296
Abstract:
http://www.nature.com/nature/journal/v461/n7261/abs/nature08296.html
Article:
http://www.nature.com/nature/journal/v461/n7261/full/nature08296.html
ErbB2 resembles an autoinhibited invertebrate epidermal growth factor
receptor
pp287-291
The tyrosine kinase receptor ErbB2 has been implicated in cancer,
particularly
breast cancer. It has been suggested that its oncogenic signalling
properties
result from the absence of a key 'tether' in the extracellular region that
autoinhibits other human ErbB receptors. ErbB2 is now shown to be the
closest
structural relative of the dEGFR receptor in Drosophila; although dEGFR also
lacks a tether, a distinct set of autoinhibitory interactions keep it
inactive.
Diego Alvarado, Daryl E. Klein and Mark A. Lemmon
doi:10.1038/nature08297
Abstract:
http://www.nature.com/nature/journal/v461/n7261/abs/nature08297.html
Article:
http://www.nature.com/nature/journal/v461/n7261/full/nature08297.html
Structure of the BK potassium channel in a lipid membrane from electron
cryomicroscopy pp292-295
Electron cryomicroscopy (cryo-EM) is an increasingly powerful method for
looking at the structures of large soluble proteins that does not require
crystallization of the proteins. Here, the first single-particle cryo-EM
study
of a membrane protein is reported- the human large-conductance calcium- and
voltage-activated potassium channel (BK) - in a lipid environment.
Liguo Wang and Fred J. Sigworth
doi:10.1038/nature08291
Abstract:
http://www.nature.com/nature/journal/v461/n7261/abs/nature08291.html
Article:
http://www.nature.com/nature/journal/v461/n7261/full/nature08291.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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