《Nature》目录要览：2009-08-06出版
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《Nature》目录要览：2009-08-06出版
封面故事： HIV-1 RNA基因组二级结构被确定
Architecture and secondary structure of an entire HIV-1 RNA genome
根据对从感染性病毒颗粒提取出的真实HIV RNA所做分析，研究人员已确定了一个完整HIV-1 RNA基因组的二级结构。单链病毒RNA基因组内的二级结构已知具有几种功能和调控作用，但此前研究人员尚未对任何病毒的完整RNA进行过全面分析。SHAPE技术（由引物延伸催化的高通量选择性2’-羟基酰化）被用来对由HIV-1 RNA基因组形成的所有结构进行定性。由此，他们发现了无数高结构性主题（其中一些发布在本期封面上），其中很多主题的功能也可以被推断出来。重要的是，RNA结构元素的存在被发现影响蛋白的翻译，有助于正确的蛋白折叠。这些结果表明，HIV-1基因组有结构，其构成元素对病毒适应性非常关键。从这项工作获得的信息，有可能使我们对HIV-1生物学有更好的认识，并有可能导致新的抗逆转录病毒干预方法的问世。本期封面图片由Lars Sahl提供。（Article p. 711; News & Views）
关于宇宙射线起源的争论（Cosmic ray origins disputed）
Beyond the myth of the supernova-remnant origin of cosmic rays
自从它们1912年被发现以来，宇宙射线一直让试图解释它们起源的理论工作者感到困惑。宇宙射线事实上是被遥远的、能量极高的事件加速到接近光速的亚原子粒子和离子流。河外宇宙射线是很有可能由包含超大质量黑洞的遥远活动星系产生的。在本期的一篇“进展综述”文章中（此文发布在我们的“国际天文年”综述文章系列中，网址为：http://tinyurl.com/prhcqy ），Yousaf Butt就当前有关“银河系”宇宙射线的正统观点发表了自己的看法。目前人们普遍接受的观点是，这些粒子流（能量不像河外宇宙射线那么高）是在与我们银河系中的强大超新星相关的冲击波中被加速的。Butt认为，说这些射线起源于某个超新星残迹的观点不成立，而且甚至认为存在不同宇宙射线加速点的观点也可能是错误的。整个“银河系”、以及被称为“超级泡泡”的结构都可能被涉及到。（Progress p. 701）
多能心脏先祖细胞中的两个微RNA（Muscle cell fate and plasticity）
miR-145 and miR-143 regulate smooth muscle cell fate and plasticity
研究表明，两个微RNA，即miR-145 和 miR-143，存在于小鼠胚胎的多能心脏先祖细胞中。miR-145是由心肌蛋白诱导的成年成纤维细胞向平滑肌细胞内的重新编程所必需的，并且足以诱导神经冠干细胞分化成“血管平滑肌细胞”（VSMC）。miR-145 和 miR-143一起以一个转录因子网络为目标，来促进平滑肌细胞的分化和抑制其增殖。这些发现提供的证据表明，微RNA能够起开关的作用，引导细胞向某个特定的体系分化。另外，miR-145 和 miR-143在调控VSMC的分化表现型和增殖表现型中所起作用在很多血管类疾病中可能是有关系的，因为VSMC在这两种状态之间的振荡有助于血管闭塞。（Article p. 705）
100亿年前的大质量致密星系（Small galaxies are great）
A high stellar velocity dispersion for a compact massive galaxy at redshift z = 2.186
研究人员认识到，宇宙中最古老和最明亮的星系可能比以前所想的更致密——它们把与当今一个椭圆形星系的质量相似的星际物质塞进了一个体积要小得多的空间中。这个认识正促使他们对与星系演化有关的一些假设重新进行评估。例如，这个认识意味着，大质量星系的大小在过去100亿年一定增长了约5倍。如果这些早期星系如同最近光度测量研究工作所反映的那么小，则组成它们的恒星应当在以比当今同样质量的恒星高得多的速度运动，这是一个与花样滑冰运动员向内收缩胳膊时所产生的快速转动相似的现象。这个观点是可以验证的。对一个高红移（z = 2.186）大质量致密星系所做的最新观测，为从光度测量推断出的星系的高质量/小尺寸组合假说提供了支持，也为认为100亿年前的大质量星系与我们今天所看到的星系很不相同的结论提供了支持。（Letter p. 717; News & Views）
火星上甲烷浓度的变化（Methane making on Mars）
Observed variations of methane on Mars unexplained by known atmospheric chemistry and physics
对火星上的甲烷所做的最新观测结果表明，甲烷浓度局部增加，并且随季节变化。不过，甲烷的光学化寿命长达几个世纪，因此它在该行星上的分布空间上应是均匀的。Frank Lefèvre 和 François Forget利用一个火星全球气候模型，同时结合相关化学方法，来研究最近所观测到的火星上甲烷的变化对于我们了解甲烷的化学问题有何意义。他们发现，按照我们当前的理解，光化学不会造成甲烷浓度发生可以测得到的变化，火星表面上甲烷的分解速度必须极快，才能解释所报告的观测结果。我们也许需要等到未来的火星探测器进行实地测量，才能发现火星甲烷到底发生了什么变化。（Letter p. 720）
地球在前寒武纪的“绿化”事件（The Precambrian: a green alternative）
The late Precambrian greening of the Earth
过去10年，几十项研究工作报告了新元古代碳酸盐岩石中碳同位素的变化，并将它们与全球碳循环的波动联系起来。Paul Knauth 和Martin Kennedy从一个侧面对这些数据进行了分析，主要关注氧同位素的测量结果（是从超过2万份样品取得的）。氧同位素的测量结果是作为碳同位素分析的一部分必然要获得的，但却常常被忽略。他们得出一个引人注目的结论：这些氧和碳同位素的组合体系与我们非常了解的显生宙样品中的相同；显生宙样品岩化在了沿海的孔隙液中，接受着含有来自陆地植物质的光合作用碳的地下水流入。被广泛报道的新元古代碳酸盐中13C/12C比例的下降并非是碳周期的波动，它们更容易通过与显生宙样品类比来理解。这个结果可能表明，在前寒武纪晚期，受由能够进行光合作用的藻类、苔藓和真菌构成的一层贴地覆盖物的影响，当时的地球正在发生“绿化”。这样一个产生氧和植物质的事件，甚至可能要对（地球）从前寒武纪的一个实质上为微生物的世界向寒武纪的一个后生动物世界的关键过渡负间接责任。（Letter p. 728; News & Views）
距今3.5万年前的五孔鸟骨长笛（Early music movement）
New flutes document the earliest musical tradition in southwestern Germany
根据本期Nature上的一篇报告，居住在欧洲的最早的现代人已有了相当复杂的音乐传统。这篇报告介绍了来自德国南部Hohle Fels洞穴中的一个五孔鸟骨长笛，距今已有3.5万年左右。我们知道还有与此年龄相当的其他长笛，但它们都没有这么复杂或完整。该长笛是由最近发现用毛象牙做成的维纳斯像（Nature 459, 248-252; 2009）的同一研究小组在同一地点附近发现的。（Letter p. 737; News & Views）
全球人口发展趋势（Global population trends）
Advances in development reverse fertility declines
不同国家财富的不断增长同时伴随着生育率的下降，所以在很多发达国际（和发展中国家），生育率已降到了低于每个妇女约生育2.1人的人口替换值。这种人口“出生荒”，再加上人口的老龄化，造成了很多困难的社会和政治问题。但是，根据对总生育率（TFR）与人类发展指数（HDI）之间的关系所做的新的横向和纵向分析，Myrskylä等人发现，在一定程度的经济发展水平之上，生育率又会开始提高，从而减缓人口老龄化的速度。因此，与当前公众及科学界的争论形成对比的是，似乎存在这样一个可能性：当处在最先进的发展阶段时，不同国家将会有一个相对来说比较稳定的人口规模；如果移民量较大时，总人口还可能有所增加。（Letter p. 741; News & Views）
精神分裂症患病风险的遗传基础（Schizophrenia genetics）
Common variants conferring risk of schizophrenia
本期Nature上三篇论文为了解基因变异和精神分裂症风险提供了线索。“国际精神分裂症联盟”在“主要组织相容性复合体”（MHC）位点内发现了共同的变异体，为涉及影响非常小的数千个共同等位基因的精神分裂症风险的一个实质性多基因成分提供了分子遗传证据。这些等位基因对患两极性疾病的风险也有贡献。Hreinn Stefansson等人介绍了一项关于单核苷酸多态性的整个基因组范围内的关联研究，发现了与不同位点的重要联系，这些位点将免疫、脑发育、记忆和认知等与患精神分裂症的倾向联系了起来。Jianxin Shi等人进行了一项对照研究，以反映MHC基因组位点与精神分裂症之间的联系。他们的结果表明，染色质蛋白有可能与这种疾病有关。通过对近1万个病例和2万个对照组进行元分析，这三项研究表明，虽然共同的基因变异影响患精神分裂症的风险，但可能只有很少或几乎没有具有很大影响的单一共同位点。（Letters pp. 744, 748, 753）
绝对蛋白定量分析方法的实际应用（Proteins by numbers）
Proteome-wide cellular protein concentrations of the human pathogen Leptospira interrogans
通过测量蛋白版本数量进行的绝对蛋白定量分析，有可能为生物学过程提供重要信息，但除了酿酒酵母的特例外，此前利用标准蛋白质组程序尚未证明这种可能性。现在，以钩端螺旋体病病原体“肾脏钩端螺旋体”作为第一个目标，一种新的质谱方法被用来确定一个蛋白质组中相当大一部分的绝对蛋白质丰度，而该方法所依据的策略应可普遍应用于很多其他的生物学体系。该研究的结果反映了“肾脏钩端螺旋体”是怎样在总蛋白版本数量保持不变的情况下通过调整蛋白质组的动态平衡来适应环境变化的。（Letter p. 762）
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NEWS AND VIEWS
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Demography: Babies make a comeback pp693-694
The population of some wealthy countries is shrinking because of a
declining birth rate. It comes as a surprise, and one with policy
implications, that after a certain point of development that trend
can reverse.
Shripad Tuljapurkar
doi:10.1038/460693a
http://www.nature.com/nature/journal/v460/n7256/full/460693a.html
Galaxy formation: Too small to ignore pp694-695
A study of one galaxy's dynamics backs up previous claims that surprisingly
compact galaxies existed in the early Universe. But how such objects blew
up in size to form present-day galaxies remains a puzzle.
Karl Glazebrook
doi:10.1038/460694a
http://www.nature.com/nature/journal/v460/n7256/full/460694a.html
Archaeology: The earliest musical tradition pp695-696
Music is a ubiquitous element in our daily lives, and was probably just
as important to our early ancestors. Fragments of ancient flutes reveal
that music was well established in Europe by about 40,000 years ago.
Daniel S. Adler
doi:10.1038/460695a
http://www.nature.com/nature/journal/v460/n7256/full/460695a.html
Structural biology: Aerial view of the HIV genome pp696-698
A bird's-eye view of the higher-order structure of HIV-1's entire RNA
genome reveals new motifs in surprising places. Structural biologists
can now zoom in on these regions to explore their functions further.
Hashim M. Al-Hashimi
doi:10.1038/460696a
http://www.nature.com/nature/journal/v460/n7256/full/460696a.html
50 & 100 years ago p697
doi:10.1038/460697a
http://www.nature.com/nature/journal/v460/n7256/full/460697a.html
Biogeochemistry: Carbonate rocks deconstructed pp698-699
The ratios of stable isotopes, especially isotopes of carbon and oxygen,
have tales to tell about Earth's history. Post-depositional alteration of
the carbonate rocks being studied may radically alter the story.
Michael A. Arthur
doi:10.1038/460698a
http://www.nature.com/nature/journal/v460/n7256/full/460698a.html
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PROGRESS
----------------------
Beyond the myth of the supernova-remnant origin of cosmic rays pp701-704
Yousaf Butt
doi:10.1038/nature08127
Abstract: http://www.nature.com/nature/journal/v460/n7256/abs/nature08127.html
Article: http://www.nature.com/nature/journal/v460/n7256/full/nature08127.html
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ARTICLES
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miR-145 and miR-143 regulate smooth muscle cell fate and plasticity
pp705-710
Evidence for a single microRNA (miRNA) that can efficiently differentiate
multipotent stem cells into a specific lineage or regulate direct reprogramming
of cells into an alternative cell fate has been elusive. Two miRNAs, miR-145
and miR-143, are now shown to be co-transcribed in multipotent cardiac
progenitors before becoming localized to smooth muscle cells. miR-145 was
found to be necessary for myocardin-induced reprogramming of adult
fibroblasts and sufficient to induce differentiation of multipotent
neural crest stem cells.
Kimberly R. Cordes et al.
doi:10.1038/nature08195
Abstract: http://www.nature.com/nature/journal/v460/n7256/abs/nature08195.html
Article: http://www.nature.com/nature/journal/v460/n7256/full/nature08195.html
Architecture and secondary structure of an entire HIV-1 RNA genome
pp711-716
Single-stranded RNA viruses are responsible for the common cold, cancer,
AIDS and other serious health threats. The genomes of these viruses form
conserved secondary structures that have functional and regulatory roles,
but most potential regulatory elements in viral RNA genomes remain
uncharacterized. Here however, the structure of an entire HIV-1 genome at
single nucleotide resolution is reported.
Joseph M. Watts et al.
doi:10.1038/nature08237
Abstract: http://www.nature.com/nature/journal/v460/n7256/abs/nature08237.html
Article: http://www.nature.com/nature/journal/v460/n7256/full/nature08237.html
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LETTERS
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A high stellar velocity dispersion for a compact massive galaxy at redshift
z = 2.186 pp717-719
The oldest and most luminous galaxies in the early Universe are surprisingly
compact, having stellar masses similar to present-day elliptical galaxies
but much smaller sizes. This suggests that massive galaxies have grown in
size by a factor of about five over the past ten billion years, leading to
the expectation that the stars in these galaxies have much higher velocities
than those in present-day galaxies of the same mass. Here, the stellar
velocity dispersion for a compact massive galaxy at redshift z = 2.186
is indeed found to be very high.
Pieter G. van Dokkum, Mariska Kriek and Marijn Franx
doi:10.1038/nature08220
Abstract: http://www.nature.com/nature/journal/v460/n7256/abs/nature08220.html
Article: http://www.nature.com/nature/journal/v460/n7256/full/nature08220.html
Observed variations of methane on Mars unexplained by known atmospheric
chemistry and physics pp720-723
Recent observations of methane on Mars suggest that methane concentrations
are locally enhanced and change with the seasons. However, methane has a
photochemical lifetime of several centuries, and is therefore expected to
have a spatially uniform distribution on the planet. Here, using a global
climate model of Mars with coupled chemistry reveals that photochemistry
as currently understood cannot explain these variations in Martian methane.
Franck Lefevre and Francois Forget
doi:10.1038/nature08228
Abstract: http://www.nature.com/nature/journal/v460/n7256/abs/nature08228.html
Article: http://www.nature.com/nature/journal/v460/n7256/full/nature08228.html
Observation of strong coupling between a micromechanical resonator and an
optical cavity field pp724-727
Achieving coherent quantum control over massive mechanical resonators via
coupling to electrons or photons is a current research goal. Here, unambiguous
evidence for strong coupling of cavity photons to a mechanical resonator
is reported, paving the way for full quantum optical control of nano- and
micromechanical devices.
Simon Groblacher, Klemens Hammerer, Michael R. Vanner and Markus Aspelmeyer
doi:10.1038/nature08171
Abstract: http://www.nature.com/nature/journal/v460/n7256/abs/nature08171.html
Article: http://www.nature.com/nature/journal/v460/n7256/full/nature08171.html
The late Precambrian greening of the Earth pp728-732
The low 13C/12C ratio in some Neoproterozoic carbonates is considered to
be evidence of carbon cycle perturbations unique to the Precambrian. Here,
all published oxygen and carbon isotope data for Neoproterozoic marine
carbonates are compiled. The combined isotope systematics are found to be
identical to those of well-understood Phanerozoic examples, suggesting an
influx of photosynthetic carbon rather than perturbations to the carbon
cycle [mdash] and implying an explosion of photosynthesizing communities
on late Precambrian land surfaces.
L. Paul Knauth and Martin J. Kennedy
doi:10.1038/nature08213
Abstract: http://www.nature.com/nature/journal/v460/n7256/abs/nature08213.html
Article: http://www.nature.com/nature/journal/v460/n7256/full/nature08213.html
Fluid and deformation regime of an advancing subduction system at Marlborough,
New Zealand pp733-736
Newly forming subduction zones on Earth can provide insights into the
evolution of major fault zone geometries from shallow levels to deep in the
lithosphere, and into the role of fluids in promoting rock failure by several
modes. The acquisition of a transect of magnetotelluric soundings across the
Marlborough strike-slip fault system of the northern South Island of New
Zealand now implicates three distinct processes connecting fluid generation
along the upper mantle plate interface to rock deformation in the crust as
the subduction zone develops.
Philip E. Wannamaker et al.
doi:10.1038/nature08204
Abstract: http://www.nature.com/nature/journal/v460/n7256/abs/nature08204.html
Article: http://www.nature.com/nature/journal/v460/n7256/full/nature08204.html
New flutes document the earliest musical tradition in southwestern Germany
pp737-740
The existence of complex musical instruments is accepted to be an indication
of fully modern behaviour and advanced symbolic communication. The discovery
of bone and ivory flutes that are around 35,000 years old at Hohle Fels in
southwestern Germany now demonstrates the presence of a well-established
musical tradition at the time when modern humans colonized Europe.
Nicholas J. Conard, Maria Malina and Susanne C. Munzel
doi:10.1038/nature08169
Abstract: http://www.nature.com/nature/journal/v460/n7256/abs/nature08169.html
Article: http://www.nature.com/nature/journal/v460/n7256/full/nature08169.html
Advances in development reverse fertility declines pp741-743
The increasing wealth of nations is accompanied by a fall in fertility such
that in many developed and developing nations fertility rates have dropped
below replacement value (less than 2.1 children per woman). Rapid population
ageing, and in some cases the prospect of significant population decline,
present difficult social and political problems. However, it is now shown
that above a certain degree of economic development fertility begins to
rise once again.
Mikko Myrskyla, Hans-Peter Kohler and Francesco C. Billari
doi:10.1038/nature08230
Abstract: http://www.nature.com/nature/journal/v460/n7256/abs/nature08230.html
Article: http://www.nature.com/nature/journal/v460/n7256/full/nature08230.html
Common variants conferring risk of schizophrenia pp744-747
Here, in the first of three papers on the genetics of schizophrenia, a genome-
wide association study of single nucleotide polymorphisms using data from
several large genome-wide scans reveals significant associations to individual
loci that implicate perturbations in immunity, brain development, memory and
cognition in the predisposition to schizophrenia.
Hreinn Stefansson et al.
doi:10.1038/nature08186
Abstract: http://www.nature.com/nature/journal/v460/n7256/abs/nature08186.html
Article: http://www.nature.com/nature/journal/v460/n7256/full/nature08186.html
Common polygenic variation contributes to risk of schizophrenia and bipolar
disorder pp748-752
In the second of three papers on the genetics of schizophrenia, a large
genome-wide association study looking at common genetic variants underlying
the risk of schizophrenia implicates the major histocompatibility complex -
and thus, immunity [mdash] and provides molecular genetic evidence for a
substantial polygenic component to the risk of schizophrenia. The latter
involves thousands of common alleles of very small effect that also contribute
to the risk of bipolar disorder.
doi:10.1038/nature08185
Abstract: http://www.nature.com/nature/journal/v460/n7256/abs/nature08185.html
Article: http://www.nature.com/nature/journal/v460/n7256/full/nature08185.html
Common variants on chromosome 6p22.1 are associated with schizophrenia pp753-757
In the third of three papers looking at the genetics of schizophrenia, a
genome-wide association study using the Molecular Genetics of Schizophrenia
case-control data set followed by a meta-analysis further implicates the major
histocompatibility complex. The study also reveals that although common
schizophrenia susceptibility alleles can be detected, there are probably
few or no single common loci with large effects.
Jianxin Shi et al.
doi:10.1038/nature08192
Abstract: http://www.nature.com/nature/journal/v460/n7256/abs/nature08192.html
Article: http://www.nature.com/nature/journal/v460/n7256/full/nature08192.html
Switch in FGF signalling initiates glial differentiation in the Drosophila
eye pp758-761
Glial cells have an essential role in the building and wiring of nervous
systems. They generally migrate over long distances before they initiate
differentiation, but the molecular pathways coordinating the switch from
glial migration to glial differentiation are largely unknown. The study of
glial cells in the Drosophila eye disc now implicates fibroblast growth
factor (FGF) signalling proteins in this process.
Sigridur Rut Franzdottir et al.
doi:10.1038/nature08167
Abstract: http://www.nature.com/nature/journal/v460/n7256/abs/nature08167.html
Article: http://www.nature.com/nature/journal/v460/n7256/full/nature08167.html
Proteome-wide cellular protein concentrations of the human pathogen
Leptospira interrogans pp762-765
Absolute protein concentration measurements of a considerable fraction of
the proteome have, until now, only been derived from genetically altered
Saccharomyces cerevisiae cells, using a technique that is not directly
portable from yeast to other species. A mass-spectrometry-based method is
now used to determine the absolute protein abundance for a significant
fraction of the proteome of the human pathogen Leptospira interrogans.
Johan Malmstrom et al.
doi:10.1038/nature08184
Abstract: http://www.nature.com/nature/journal/v460/n7256/abs/nature08184.html
Article: http://www.nature.com/nature/journal/v460/n7256/full/nature08184.html
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CORRIGENDUM
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Warming of the Antarctic ice-sheet surface since the 1957 International
Geophysical Year p766
Eric J. Steig et al.
doi:10.1038/nature08286
http://www.nature.com/nature/journal/v460/n7256/full/nature08286.html
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FUTURES
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Expatriate p772
Contact has been made.
Julian Tang
doi:10.1038/460772a
http://www.nature.com/nature/journal/v460/n7256/full/460772a.html
Architecture and secondary structure of an entire HIV-1 RNA genome
根据对从感染性病毒颗粒提取出的真实HIV RNA所做分析，研究人员已确定了一个完整HIV-1 RNA基因组的二级结构。单链病毒RNA基因组内的二级结构已知具有几种功能和调控作用，但此前研究人员尚未对任何病毒的完整RNA进行过全面分析。SHAPE技术（由引物延伸催化的高通量选择性2’-羟基酰化）被用来对由HIV-1 RNA基因组形成的所有结构进行定性。由此，他们发现了无数高结构性主题（其中一些发布在本期封面上），其中很多主题的功能也可以被推断出来。重要的是，RNA结构元素的存在被发现影响蛋白的翻译，有助于正确的蛋白折叠。这些结果表明，HIV-1基因组有结构，其构成元素对病毒适应性非常关键。从这项工作获得的信息，有可能使我们对HIV-1生物学有更好的认识，并有可能导致新的抗逆转录病毒干预方法的问世。本期封面图片由Lars Sahl提供。（Article p. 711; News & Views）
关于宇宙射线起源的争论（Cosmic ray origins disputed）
Beyond the myth of the supernova-remnant origin of cosmic rays
自从它们1912年被发现以来，宇宙射线一直让试图解释它们起源的理论工作者感到困惑。宇宙射线事实上是被遥远的、能量极高的事件加速到接近光速的亚原子粒子和离子流。河外宇宙射线是很有可能由包含超大质量黑洞的遥远活动星系产生的。在本期的一篇“进展综述”文章中（此文发布在我们的“国际天文年”综述文章系列中，网址为：http://tinyurl.com/prhcqy ），Yousaf Butt就当前有关“银河系”宇宙射线的正统观点发表了自己的看法。目前人们普遍接受的观点是，这些粒子流（能量不像河外宇宙射线那么高）是在与我们银河系中的强大超新星相关的冲击波中被加速的。Butt认为，说这些射线起源于某个超新星残迹的观点不成立，而且甚至认为存在不同宇宙射线加速点的观点也可能是错误的。整个“银河系”、以及被称为“超级泡泡”的结构都可能被涉及到。（Progress p. 701）
多能心脏先祖细胞中的两个微RNA（Muscle cell fate and plasticity）
miR-145 and miR-143 regulate smooth muscle cell fate and plasticity
研究表明，两个微RNA，即miR-145 和 miR-143，存在于小鼠胚胎的多能心脏先祖细胞中。miR-145是由心肌蛋白诱导的成年成纤维细胞向平滑肌细胞内的重新编程所必需的，并且足以诱导神经冠干细胞分化成“血管平滑肌细胞”（VSMC）。miR-145 和 miR-143一起以一个转录因子网络为目标，来促进平滑肌细胞的分化和抑制其增殖。这些发现提供的证据表明，微RNA能够起开关的作用，引导细胞向某个特定的体系分化。另外，miR-145 和 miR-143在调控VSMC的分化表现型和增殖表现型中所起作用在很多血管类疾病中可能是有关系的，因为VSMC在这两种状态之间的振荡有助于血管闭塞。（Article p. 705）
100亿年前的大质量致密星系（Small galaxies are great）
A high stellar velocity dispersion for a compact massive galaxy at redshift z = 2.186
研究人员认识到，宇宙中最古老和最明亮的星系可能比以前所想的更致密——它们把与当今一个椭圆形星系的质量相似的星际物质塞进了一个体积要小得多的空间中。这个认识正促使他们对与星系演化有关的一些假设重新进行评估。例如，这个认识意味着，大质量星系的大小在过去100亿年一定增长了约5倍。如果这些早期星系如同最近光度测量研究工作所反映的那么小，则组成它们的恒星应当在以比当今同样质量的恒星高得多的速度运动，这是一个与花样滑冰运动员向内收缩胳膊时所产生的快速转动相似的现象。这个观点是可以验证的。对一个高红移（z = 2.186）大质量致密星系所做的最新观测，为从光度测量推断出的星系的高质量/小尺寸组合假说提供了支持，也为认为100亿年前的大质量星系与我们今天所看到的星系很不相同的结论提供了支持。（Letter p. 717; News & Views）
火星上甲烷浓度的变化（Methane making on Mars）
Observed variations of methane on Mars unexplained by known atmospheric chemistry and physics
对火星上的甲烷所做的最新观测结果表明，甲烷浓度局部增加，并且随季节变化。不过，甲烷的光学化寿命长达几个世纪，因此它在该行星上的分布空间上应是均匀的。Frank Lefèvre 和 François Forget利用一个火星全球气候模型，同时结合相关化学方法，来研究最近所观测到的火星上甲烷的变化对于我们了解甲烷的化学问题有何意义。他们发现，按照我们当前的理解，光化学不会造成甲烷浓度发生可以测得到的变化，火星表面上甲烷的分解速度必须极快，才能解释所报告的观测结果。我们也许需要等到未来的火星探测器进行实地测量，才能发现火星甲烷到底发生了什么变化。（Letter p. 720）
地球在前寒武纪的“绿化”事件（The Precambrian: a green alternative）
The late Precambrian greening of the Earth
过去10年，几十项研究工作报告了新元古代碳酸盐岩石中碳同位素的变化，并将它们与全球碳循环的波动联系起来。Paul Knauth 和Martin Kennedy从一个侧面对这些数据进行了分析，主要关注氧同位素的测量结果（是从超过2万份样品取得的）。氧同位素的测量结果是作为碳同位素分析的一部分必然要获得的，但却常常被忽略。他们得出一个引人注目的结论：这些氧和碳同位素的组合体系与我们非常了解的显生宙样品中的相同；显生宙样品岩化在了沿海的孔隙液中，接受着含有来自陆地植物质的光合作用碳的地下水流入。被广泛报道的新元古代碳酸盐中13C/12C比例的下降并非是碳周期的波动，它们更容易通过与显生宙样品类比来理解。这个结果可能表明，在前寒武纪晚期，受由能够进行光合作用的藻类、苔藓和真菌构成的一层贴地覆盖物的影响，当时的地球正在发生“绿化”。这样一个产生氧和植物质的事件，甚至可能要对（地球）从前寒武纪的一个实质上为微生物的世界向寒武纪的一个后生动物世界的关键过渡负间接责任。（Letter p. 728; News & Views）
距今3.5万年前的五孔鸟骨长笛（Early music movement）
New flutes document the earliest musical tradition in southwestern Germany
根据本期Nature上的一篇报告，居住在欧洲的最早的现代人已有了相当复杂的音乐传统。这篇报告介绍了来自德国南部Hohle Fels洞穴中的一个五孔鸟骨长笛，距今已有3.5万年左右。我们知道还有与此年龄相当的其他长笛，但它们都没有这么复杂或完整。该长笛是由最近发现用毛象牙做成的维纳斯像（Nature 459, 248-252; 2009）的同一研究小组在同一地点附近发现的。（Letter p. 737; News & Views）
全球人口发展趋势（Global population trends）
Advances in development reverse fertility declines
不同国家财富的不断增长同时伴随着生育率的下降，所以在很多发达国际（和发展中国家），生育率已降到了低于每个妇女约生育2.1人的人口替换值。这种人口“出生荒”，再加上人口的老龄化，造成了很多困难的社会和政治问题。但是，根据对总生育率（TFR）与人类发展指数（HDI）之间的关系所做的新的横向和纵向分析，Myrskylä等人发现，在一定程度的经济发展水平之上，生育率又会开始提高，从而减缓人口老龄化的速度。因此，与当前公众及科学界的争论形成对比的是，似乎存在这样一个可能性：当处在最先进的发展阶段时，不同国家将会有一个相对来说比较稳定的人口规模；如果移民量较大时，总人口还可能有所增加。（Letter p. 741; News & Views）
精神分裂症患病风险的遗传基础（Schizophrenia genetics）
Common variants conferring risk of schizophrenia
本期Nature上三篇论文为了解基因变异和精神分裂症风险提供了线索。“国际精神分裂症联盟”在“主要组织相容性复合体”（MHC）位点内发现了共同的变异体，为涉及影响非常小的数千个共同等位基因的精神分裂症风险的一个实质性多基因成分提供了分子遗传证据。这些等位基因对患两极性疾病的风险也有贡献。Hreinn Stefansson等人介绍了一项关于单核苷酸多态性的整个基因组范围内的关联研究，发现了与不同位点的重要联系，这些位点将免疫、脑发育、记忆和认知等与患精神分裂症的倾向联系了起来。Jianxin Shi等人进行了一项对照研究，以反映MHC基因组位点与精神分裂症之间的联系。他们的结果表明，染色质蛋白有可能与这种疾病有关。通过对近1万个病例和2万个对照组进行元分析，这三项研究表明，虽然共同的基因变异影响患精神分裂症的风险，但可能只有很少或几乎没有具有很大影响的单一共同位点。（Letters pp. 744, 748, 753）
绝对蛋白定量分析方法的实际应用（Proteins by numbers）
Proteome-wide cellular protein concentrations of the human pathogen Leptospira interrogans
通过测量蛋白版本数量进行的绝对蛋白定量分析，有可能为生物学过程提供重要信息，但除了酿酒酵母的特例外，此前利用标准蛋白质组程序尚未证明这种可能性。现在，以钩端螺旋体病病原体“肾脏钩端螺旋体”作为第一个目标，一种新的质谱方法被用来确定一个蛋白质组中相当大一部分的绝对蛋白质丰度，而该方法所依据的策略应可普遍应用于很多其他的生物学体系。该研究的结果反映了“肾脏钩端螺旋体”是怎样在总蛋白版本数量保持不变的情况下通过调整蛋白质组的动态平衡来适应环境变化的。（Letter p. 762）
----------------------
NEWS AND VIEWS
----------------------
Demography: Babies make a comeback pp693-694
The population of some wealthy countries is shrinking because of a
declining birth rate. It comes as a surprise, and one with policy
implications, that after a certain point of development that trend
can reverse.
Shripad Tuljapurkar
doi:10.1038/460693a
http://www.nature.com/nature/journal/v460/n7256/full/460693a.html
Galaxy formation: Too small to ignore pp694-695
A study of one galaxy's dynamics backs up previous claims that surprisingly
compact galaxies existed in the early Universe. But how such objects blew
up in size to form present-day galaxies remains a puzzle.
Karl Glazebrook
doi:10.1038/460694a
http://www.nature.com/nature/journal/v460/n7256/full/460694a.html
Archaeology: The earliest musical tradition pp695-696
Music is a ubiquitous element in our daily lives, and was probably just
as important to our early ancestors. Fragments of ancient flutes reveal
that music was well established in Europe by about 40,000 years ago.
Daniel S. Adler
doi:10.1038/460695a
http://www.nature.com/nature/journal/v460/n7256/full/460695a.html
Structural biology: Aerial view of the HIV genome pp696-698
A bird's-eye view of the higher-order structure of HIV-1's entire RNA
genome reveals new motifs in surprising places. Structural biologists
can now zoom in on these regions to explore their functions further.
Hashim M. Al-Hashimi
doi:10.1038/460696a
http://www.nature.com/nature/journal/v460/n7256/full/460696a.html
50 & 100 years ago p697
doi:10.1038/460697a
http://www.nature.com/nature/journal/v460/n7256/full/460697a.html
Biogeochemistry: Carbonate rocks deconstructed pp698-699
The ratios of stable isotopes, especially isotopes of carbon and oxygen,
have tales to tell about Earth's history. Post-depositional alteration of
the carbonate rocks being studied may radically alter the story.
Michael A. Arthur
doi:10.1038/460698a
http://www.nature.com/nature/journal/v460/n7256/full/460698a.html
----------------------
PROGRESS
----------------------
Beyond the myth of the supernova-remnant origin of cosmic rays pp701-704
Yousaf Butt
doi:10.1038/nature08127
Abstract: http://www.nature.com/nature/journal/v460/n7256/abs/nature08127.html
Article: http://www.nature.com/nature/journal/v460/n7256/full/nature08127.html
----------------------
ARTICLES
----------------------
miR-145 and miR-143 regulate smooth muscle cell fate and plasticity
pp705-710
Evidence for a single microRNA (miRNA) that can efficiently differentiate
multipotent stem cells into a specific lineage or regulate direct reprogramming
of cells into an alternative cell fate has been elusive. Two miRNAs, miR-145
and miR-143, are now shown to be co-transcribed in multipotent cardiac
progenitors before becoming localized to smooth muscle cells. miR-145 was
found to be necessary for myocardin-induced reprogramming of adult
fibroblasts and sufficient to induce differentiation of multipotent
neural crest stem cells.
Kimberly R. Cordes et al.
doi:10.1038/nature08195
Abstract: http://www.nature.com/nature/journal/v460/n7256/abs/nature08195.html
Article: http://www.nature.com/nature/journal/v460/n7256/full/nature08195.html
Architecture and secondary structure of an entire HIV-1 RNA genome
pp711-716
Single-stranded RNA viruses are responsible for the common cold, cancer,
AIDS and other serious health threats. The genomes of these viruses form
conserved secondary structures that have functional and regulatory roles,
but most potential regulatory elements in viral RNA genomes remain
uncharacterized. Here however, the structure of an entire HIV-1 genome at
single nucleotide resolution is reported.
Joseph M. Watts et al.
doi:10.1038/nature08237
Abstract: http://www.nature.com/nature/journal/v460/n7256/abs/nature08237.html
Article: http://www.nature.com/nature/journal/v460/n7256/full/nature08237.html
----------------------
LETTERS
----------------------
A high stellar velocity dispersion for a compact massive galaxy at redshift
z = 2.186 pp717-719
The oldest and most luminous galaxies in the early Universe are surprisingly
compact, having stellar masses similar to present-day elliptical galaxies
but much smaller sizes. This suggests that massive galaxies have grown in
size by a factor of about five over the past ten billion years, leading to
the expectation that the stars in these galaxies have much higher velocities
than those in present-day galaxies of the same mass. Here, the stellar
velocity dispersion for a compact massive galaxy at redshift z = 2.186
is indeed found to be very high.
Pieter G. van Dokkum, Mariska Kriek and Marijn Franx
doi:10.1038/nature08220
Abstract: http://www.nature.com/nature/journal/v460/n7256/abs/nature08220.html
Article: http://www.nature.com/nature/journal/v460/n7256/full/nature08220.html
Observed variations of methane on Mars unexplained by known atmospheric
chemistry and physics pp720-723
Recent observations of methane on Mars suggest that methane concentrations
are locally enhanced and change with the seasons. However, methane has a
photochemical lifetime of several centuries, and is therefore expected to
have a spatially uniform distribution on the planet. Here, using a global
climate model of Mars with coupled chemistry reveals that photochemistry
as currently understood cannot explain these variations in Martian methane.
Franck Lefevre and Francois Forget
doi:10.1038/nature08228
Abstract: http://www.nature.com/nature/journal/v460/n7256/abs/nature08228.html
Article: http://www.nature.com/nature/journal/v460/n7256/full/nature08228.html
Observation of strong coupling between a micromechanical resonator and an
optical cavity field pp724-727
Achieving coherent quantum control over massive mechanical resonators via
coupling to electrons or photons is a current research goal. Here, unambiguous
evidence for strong coupling of cavity photons to a mechanical resonator
is reported, paving the way for full quantum optical control of nano- and
micromechanical devices.
Simon Groblacher, Klemens Hammerer, Michael R. Vanner and Markus Aspelmeyer
doi:10.1038/nature08171
Abstract: http://www.nature.com/nature/journal/v460/n7256/abs/nature08171.html
Article: http://www.nature.com/nature/journal/v460/n7256/full/nature08171.html
The late Precambrian greening of the Earth pp728-732
The low 13C/12C ratio in some Neoproterozoic carbonates is considered to
be evidence of carbon cycle perturbations unique to the Precambrian. Here,
all published oxygen and carbon isotope data for Neoproterozoic marine
carbonates are compiled. The combined isotope systematics are found to be
identical to those of well-understood Phanerozoic examples, suggesting an
influx of photosynthetic carbon rather than perturbations to the carbon
cycle [mdash] and implying an explosion of photosynthesizing communities
on late Precambrian land surfaces.
L. Paul Knauth and Martin J. Kennedy
doi:10.1038/nature08213
Abstract: http://www.nature.com/nature/journal/v460/n7256/abs/nature08213.html
Article: http://www.nature.com/nature/journal/v460/n7256/full/nature08213.html
Fluid and deformation regime of an advancing subduction system at Marlborough,
New Zealand pp733-736
Newly forming subduction zones on Earth can provide insights into the
evolution of major fault zone geometries from shallow levels to deep in the
lithosphere, and into the role of fluids in promoting rock failure by several
modes. The acquisition of a transect of magnetotelluric soundings across the
Marlborough strike-slip fault system of the northern South Island of New
Zealand now implicates three distinct processes connecting fluid generation
along the upper mantle plate interface to rock deformation in the crust as
the subduction zone develops.
Philip E. Wannamaker et al.
doi:10.1038/nature08204
Abstract: http://www.nature.com/nature/journal/v460/n7256/abs/nature08204.html
Article: http://www.nature.com/nature/journal/v460/n7256/full/nature08204.html
New flutes document the earliest musical tradition in southwestern Germany
pp737-740
The existence of complex musical instruments is accepted to be an indication
of fully modern behaviour and advanced symbolic communication. The discovery
of bone and ivory flutes that are around 35,000 years old at Hohle Fels in
southwestern Germany now demonstrates the presence of a well-established
musical tradition at the time when modern humans colonized Europe.
Nicholas J. Conard, Maria Malina and Susanne C. Munzel
doi:10.1038/nature08169
Abstract: http://www.nature.com/nature/journal/v460/n7256/abs/nature08169.html
Article: http://www.nature.com/nature/journal/v460/n7256/full/nature08169.html
Advances in development reverse fertility declines pp741-743
The increasing wealth of nations is accompanied by a fall in fertility such
that in many developed and developing nations fertility rates have dropped
below replacement value (less than 2.1 children per woman). Rapid population
ageing, and in some cases the prospect of significant population decline,
present difficult social and political problems. However, it is now shown
that above a certain degree of economic development fertility begins to
rise once again.
Mikko Myrskyla, Hans-Peter Kohler and Francesco C. Billari
doi:10.1038/nature08230
Abstract: http://www.nature.com/nature/journal/v460/n7256/abs/nature08230.html
Article: http://www.nature.com/nature/journal/v460/n7256/full/nature08230.html
Common variants conferring risk of schizophrenia pp744-747
Here, in the first of three papers on the genetics of schizophrenia, a genome-
wide association study of single nucleotide polymorphisms using data from
several large genome-wide scans reveals significant associations to individual
loci that implicate perturbations in immunity, brain development, memory and
cognition in the predisposition to schizophrenia.
Hreinn Stefansson et al.
doi:10.1038/nature08186
Abstract: http://www.nature.com/nature/journal/v460/n7256/abs/nature08186.html
Article: http://www.nature.com/nature/journal/v460/n7256/full/nature08186.html
Common polygenic variation contributes to risk of schizophrenia and bipolar
disorder pp748-752
In the second of three papers on the genetics of schizophrenia, a large
genome-wide association study looking at common genetic variants underlying
the risk of schizophrenia implicates the major histocompatibility complex -
and thus, immunity [mdash] and provides molecular genetic evidence for a
substantial polygenic component to the risk of schizophrenia. The latter
involves thousands of common alleles of very small effect that also contribute
to the risk of bipolar disorder.
doi:10.1038/nature08185
Abstract: http://www.nature.com/nature/journal/v460/n7256/abs/nature08185.html
Article: http://www.nature.com/nature/journal/v460/n7256/full/nature08185.html
Common variants on chromosome 6p22.1 are associated with schizophrenia pp753-757
In the third of three papers looking at the genetics of schizophrenia, a
genome-wide association study using the Molecular Genetics of Schizophrenia
case-control data set followed by a meta-analysis further implicates the major
histocompatibility complex. The study also reveals that although common
schizophrenia susceptibility alleles can be detected, there are probably
few or no single common loci with large effects.
Jianxin Shi et al.
doi:10.1038/nature08192
Abstract: http://www.nature.com/nature/journal/v460/n7256/abs/nature08192.html
Article: http://www.nature.com/nature/journal/v460/n7256/full/nature08192.html
Switch in FGF signalling initiates glial differentiation in the Drosophila
eye pp758-761
Glial cells have an essential role in the building and wiring of nervous
systems. They generally migrate over long distances before they initiate
differentiation, but the molecular pathways coordinating the switch from
glial migration to glial differentiation are largely unknown. The study of
glial cells in the Drosophila eye disc now implicates fibroblast growth
factor (FGF) signalling proteins in this process.
Sigridur Rut Franzdottir et al.
doi:10.1038/nature08167
Abstract: http://www.nature.com/nature/journal/v460/n7256/abs/nature08167.html
Article: http://www.nature.com/nature/journal/v460/n7256/full/nature08167.html
Proteome-wide cellular protein concentrations of the human pathogen
Leptospira interrogans pp762-765
Absolute protein concentration measurements of a considerable fraction of
the proteome have, until now, only been derived from genetically altered
Saccharomyces cerevisiae cells, using a technique that is not directly
portable from yeast to other species. A mass-spectrometry-based method is
now used to determine the absolute protein abundance for a significant
fraction of the proteome of the human pathogen Leptospira interrogans.
Johan Malmstrom et al.
doi:10.1038/nature08184
Abstract: http://www.nature.com/nature/journal/v460/n7256/abs/nature08184.html
Article: http://www.nature.com/nature/journal/v460/n7256/full/nature08184.html
----------------------
CORRIGENDUM
----------------------
Warming of the Antarctic ice-sheet surface since the 1957 International
Geophysical Year p766
Eric J. Steig et al.
doi:10.1038/nature08286
http://www.nature.com/nature/journal/v460/n7256/full/nature08286.html
----------------------
FUTURES
----------------------
Expatriate p772
Contact has been made.
Julian Tang
doi:10.1038/460772a
http://www.nature.com/nature/journal/v460/n7256/full/460772a.html
环境科学之家（http://www.eschina.org.cn/）
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