《Nature》目录要览：2009-10-29出版
时间：2009-10-29 阅读： 我要评论:
《Nature》目录要览：2009-10-29出版
封面故事：“有质动力”的一种新形式
Acceleration of neutral atoms in strong short-pulse laser fields
Nature杂志上1957年发表的一篇论文（http://tinyurl.com/kpfla4），描述了作用在
由关于洛伦兹电磁力的方程所产生的一个非均匀电场中带电粒子的一种力。研究人员很
快意识到，这种被称为“有质动力”的力有可能被用来束缚和控制电子。但是，这种力
很弱，而且直到现代激光出现之后，它才在粒子加速器和惯性约束聚变装置中得到利
用。现在，这种力的一种新的存在形式已经被发现。Ulrich Eichman等人对作用在短脉
冲激光场中的中性原子上的以前没有被人们考虑过的强运动力进行了观察。作用在电子
上的“有质动力”是它们的驱动机制，能造成中性原子的超强加速，加速作用比地球引
力加速大14个数量级。如此强的一种力可能导致基础物理和应用物理中新应用的问世。
本期封面所示为在与一个聚焦的激光束相互作用后中性氦原子所发生的偏移。（Letter
p. 1261）
地球上水的起源问题（Dry at first, wet later）
Volatile accretion history of the terrestrial planets and dynamic
implications
水是地球上的生物所必需的，所以有关我们的水是从哪里来的问题是一个人们相当感兴
趣的问题。Francis Albarede对有关下面这个假设的证据进行了分析：在导致月球形成
的巨大碰撞发生之时，撞击的天体和原始地球基本上都是干的，只是在过了很长时间之
后通过从小行星带不断吸积湿的东西才获得了挥发性物质。他的结论是，这种水向地幔
中的引入可能触发了板块构造，而且这一机制对年轻的金星也可能曾发挥过作用，但对
火星似乎未能起作用。（Progress p. 1227）这篇论文是我们“国际天文年”纪念活动
系列文章之一，也发布在http://tinyurl.com/prhcqy上。
核糖体结构和功能研究方面的最新进展（Ribosomes in translation）
What recent ribosome structures have revealed about the mechanism of
translation
在一篇恰逢其时的“Review”文章中，2009年诺贝尔化学奖得主之一的Venkatraman
Ramakrishnan及其同事Martin Schmeing，对有关核糖体结构和功能研究方面的最新进
展进行了综述。以细菌转录的主要方面（这些方面对于所有蛋白的合成都应是共同的）
为重点，他们介绍了有关核糖体结构的知识是怎样越来越多地推动着复杂的生物化学和
遗传学实验工作。除了对基础转录研究的影响外，细菌结构知识还为开发更好的抗生素
提供了一个框架。（Review p. 1234）关于对Venkatraman Ramakrishnan的视频访谈，
请访问Nature Video YouTube频道，网址为：
www.youtube.com/user/NatureVideoChannel。
基因组演化的速度和模式（The generation game）
Genome evolution and adaptation in a long-term experiment with Escherichia
coli
在一项实验中，研究人员在实验室中培养了一批大肠杆菌，它们在近20年时间里一直以
葡萄糖为一种限制性营养物。这项实验为研究基因组演化的速度和模式提供了一个机
会。大肠杆菌克隆的基因组分别在2,000代、5,000代、10,000代、15,000代、20,000代
和 40,000代后被取样。适应性的发展加速极快，但基因组演化在20,000代几乎是不变
的。这样的一致性被认为是中性演化的特点，但来自几个方面的证据都表明，这些突变
大部分都是有益的。这个种群后来突变速度加快，并且积累了数百个另外的、以中性为
特征的突变。显然，基因组演化和适应性演化之间的耦合是一个复杂的问题。
（Article p. 1243; News & Views）
序列特异性DNA结合蛋白寻找目标的方式（Major to minor）
The role of DNA shape in protein–DNA recognition
序列特异性DNA结合蛋白何以能在数量巨大的非特异性DNA中找到目标是一个长期未解之
谜。一个比较受欢迎的模型是，序列是作为DNA螺旋的“大沟”中蛋白与碱基之间氢键
的形成被读取的。对蛋白-DNA复合物三维结构所做的一项新的分析表明，DNA形状是识
别的关键。DNA序列的前后部分通过让精氨酸优先与带负电的“口袋”结合改变DNA螺旋
“小沟”的宽度。DNA在核小体核心颗粒中的定位是这一效应的一个例子。（Article
p. 1248; News & Views）
伽马射线暴GRB 090423的红移值（Bursting at high redshift）
A -ray burst at a redshift of z 8.2 / GRB 090423 at a redshift of z 8.1
两个小组在本期Nature上发表了伽马射线暴GRB 090423的红移值和其他光谱数据。
Savaterra等人报告了其由Swift卫星在2009年4月23日获得的最初探测结果，以及在该
伽马射线暴发生14小时之后由位于La Palma的伽利略国家望远镜进行的一次红移测定，
所得值为z = 8.1。Tanvir等人利用位于夏威夷的英国红外天文望远镜在该伽马射线暴
发生约20分钟之后进行了红移测定，所得值为z = 8.1。 这些红移值与以前获得的任何
一个天体的已知最高红移值形成对比，后者为z = 6.96，是一个发射Lyman-α的星系的
红移值。这些测量值意味着，早在“大爆炸”之后约6亿年，大质量恒星就在随着伽马
射线暴的发生而生成和死亡，而且它们的性质与100亿年之后产生伽马射线暴的那些恒
星非常相似。（Letters pp. 1254, 1258; News & Views）
减小电子自旋与其环境相互作用噪音的方式（Tone down the noise）
Preserving electron spin coherence in solids by optimal dynamical decoupling
如果固体物质中的电子自旋要在量子计算机中得到利用，就需要减小不可避免会随自旋
与其环境相互作用出现的量子“噪音”。 现在，在发生脉冲式电子顺磁共振的丙二酸
单晶中所做的实验表明，这是可以做到的。利用外部脉冲诱导电子自旋去“翻转”最佳
的次数，会使其与环境相互作用所产生的噪音均匀化至零，而且自旋相干性所维持的时
间尺度也得到显著增加——在所研究的体系中从0.04 微秒增加到了30微秒。（Letter
p. 1265; News & Views）
鸟类磁定向能力与其眼睛有关（Bird navigation: the eyes have it）
Visual but not trigeminal mediation of magnetic compass information in a
migratory bird
鸟儿怎样找到回家的路？所有人都同意动物能够利用地球磁场来形成一个体内“罗盘”
以感应方向的说法，但人们观点的一致性也就到此为止。一些研究人员提出这样一个观
点：磁性是由鸟喙中连接到三叉神经上的磁体来探测的；另一些研究人员则认为，磁性
是通过眼睛经由一个复杂的光敏机制来传导的。对后一个观点（即有关眼睛所起作用的
观点）的支持，来自对欧洲知更鸟的一项神经外科和行为学研究。在脑中一个被称为
“cluster N”的中心有病灶的鸟被发现缺乏磁定向能力。而且至少在这种候鸟中，其
喙中假设存在的磁受体在磁性罗盘定向中没有起作用。（Letter p. 1274）
宿主-细菌相互作用现象（Host–bacteria phenomena）
Regulation of inflammatory responses by gut microbiota and chemoattractant
receptor GPR43 / Resolvin D2 is a potent regulator of leukocytes and
controls microbial sepsis
本期Nature上两篇论文凸显了有关小肠细菌与其宿主相互作用的研究工作的价值。最新
证据表明，小肠有益菌的产物能抵抗炎症和I-型糖尿病。结肠中的共生菌已知能发酵食
物纤维产生短链脂肪酸，而现在对一个小鼠结肠炎模型所做的一项研究表明，这些脂肪
酸能够通过刺激嗜中性细胞上的化学吸引剂受体GPR43来抑制先天性和炎性反应。这说
明短链脂肪酸与GPR43之间的相互作用为操控免疫反应的一个可能的目标。（Letter p.
1282）来自omega-3脂肪酸的局部发挥作用的Resolvins已被发现是消炎调控因子。现
在，对一个小鼠腹腔脓毒症模型所做研究表明，Resolvin D2 (RvD2)抑制嗜中性细胞向
发炎处的运送，降低白细胞与内皮细胞的相互作用。RvD2的细胞和分子作用转变成急剧
增加的存活率。这一发现表明，RvD2是一种强效消炎药物，同时也提出了不会降低宿主
防卫能力的新治疗方法。（Letter p. 1287）
外胚层细胞重新获得多能性的方式（Epiblasts regain pluripotency）
Epigenetic reversion of post-implantation epiblast to pluripotent embryonic
stem cells
首次在囊胚期胚胎的原始外胚层细胞中形成的多能状态，在随后的发育中会失去。现
在，Bao等人发现，来自形成时间已长达7.5天的小鼠胚胎的高级植入后外胚层细胞，可
通过暴露于LIF/STAT3信号作用而被重新编程回到多能状态。它们在转录组（细胞中的
全部mRNA）中发现了伴随的变化，这些变化导致见于外胚层细胞中的表型记忆和外遗传
记忆的丧失。以这种方式重新编程的细胞会形成银鲛的体细胞组织和生殖细胞，与能够
自我更新的外胚层干细胞不同。这项工作为研究信号作用和外遗传重新编程会怎样促进
多能性的重新获得提供了一个模型。（Letter p. 1292）
利用酶基质结合能进行催化方面的非对称性（Enzyme catalysis）
Exploitation of binding energy for catalysis and design
酶利用基质结合能来促进基态结合和选择性地降低反应过渡态的能量。Thyme等人已确
定，对单体“归巢”核酸内切酶I-AniI（该酶能以高序列特异性分解双链DNA）来说，
这种酶的N-端区域的突变造成某些运动参数（KA 和 KM）增加，而C-端区域的突变则减
小另一运动参数（kcat）。在利用酶基质结合能进行催化方面的这一出乎意料的非对称
性，也许使研究人员能够更有效地重新设计核酸内切酶，来分解基因组目标点，用于基
因疗法和其他生物医学应用。（Letter p. 1300）
----------------------
NEWS AND VIEWS
----------------------
Quantum information: Caught at the finishing line pp1217-1218
Quantum systems habitually leak information, limiting their usefulness
for practical applications. By optimally reversing the leak, this
information loss has been reduced to a trickle in the solid state.
Bob B. Buckley and David D. Awschalom
doi:10.1038/4611217a
http://www.nature.com/nature/journal/v461/n7268/full/4611217a.html
Materials science: Emerging routes to multiferroics pp1218-1219
Materials that combine ferroic properties [mdash] such as ferromagnetism
and ferroelectricity [mdash] are highly desirable, but rare. A new class
of multiferroic solids heralds a fresh approach for making such materials.
Ramamoorthy Ramesh
doi:10.1038/4611218a
http://www.nature.com/nature/journal/v461/n7268/full/4611218a.html
Evolutionary biology: Arrhythmia of tempo and mode pp1219-1221
An exercise in experimental evolution using bacteria has been running for
more than 20 years and 40,000 generations. The results to date provide
a glimpse of a new world, and are cause for both delight and unease.
Paul B. Rainey
doi:10.1038/4611219a
http://www.nature.com/nature/journal/v461/n7268/full/4611219a.html
Astrophysics: Most distant cosmic blast seen pp1221-1223
The most distant [gamma]-ray burst yet sighted is the earliest astronomical
object ever observed in cosmic history. This ancient beacon offers a
glimpse of the little-known cosmic dark ages.
Bing Zhang
doi:10.1038/4611221a
http://www.nature.com/nature/journal/v461/n7268/full/4611221a.html
Catalysis: Bond control in surface reactions pp1223-1225
Catalysts steer reactions towards certain products [mdash] but the basis
of their control is often unclear. Quantum chemical calculations reveal
which parameters control bond formation in a network of catalytic reactions.
Jens K. Norskov and Frank Abild-Pedersen
doi:10.1038/4611223a
http://www.nature.com/nature/journal/v461/n7268/full/4611223a.html
Structural biology: DNA binding shapes up pp1225-1226
DNA-binding proteins have the daunting task of finding their binding sites
among the 3 billion base pairs of the human genome. The shape of DNA, and
not just its sequence, may offer proteins much-needed direction.
Tom Tullius
doi:10.1038/4611225a
http://www.nature.com/nature/journal/v461/n7268/full/4611225a.html
Statistical physics: Swirled by light p1226
A micrometre-sized particle immersed in a liquid can be trapped by light.
An experiment shows that the trapping can be accompanied by a whirling
whose direction can be reversed by changing the light intensity.
Mark I. Dykman
doi:10.1038/4611226a
http://www.nature.com/nature/journal/v461/n7268/full/4611226a.html
----------------------
PROGRESS
----------------------
Volatile accretion history of the terrestrial planets and dynamic
implications pp1227-1233
Francis Albarede
doi:10.1038/nature08477
Abstract:
http://www.nature.com/nature/journal/v461/n7268/abs/nature08477.html
Article:
http://www.nature.com/nature/journal/v461/n7268/full/nature08477.html
----------------------
REVIEW
----------------------
What recent ribosome structures have revealed about the mechanism of
translation pp1234-1242
T. Martin Schmeing and V. Ramakrishnan
doi:10.1038/nature08403
Abstract:
http://www.nature.com/nature/journal/v461/n7268/abs/nature08403.html
Article:
http://www.nature.com/nature/journal/v461/n7268/full/nature08403.html
----------------------
ARTICLES
----------------------
Genome evolution and adaptation in a long-term experiment with
Escherichia coli pp1243-1247
Here, in order to gain insight into the relationship between rates of
genomic evolution and organismal adaptation, genomes sampled through 40,000
generations are sequenced from a laboratory population of Escherichia coli.
The results indicate that the coupling between genomic and adaptive
evolution
is complex and can be counterintuitive even in a constant environment, with
beneficial mutations surprisingly uniform over time whereas neutral
substitutions were highly variable.
Jeffrey E. Barrick et al.
doi:10.1038/nature08480
Abstract:
http://www.nature.com/nature/journal/v461/n7268/abs/nature08480.html
Article:
http://www.nature.com/nature/journal/v461/n7268/full/nature08480.html
The role of DNA shape in protein-DNA recognition pp1248-1253
The question of how proteins recognize specific DNA sequences in the face of
vastly higher concentrations of non-specific DNA remains unclear. One
suggested mechanism involves the formation of hydrogen bonds with specific
bases, primarily in the major groove. The comprehensive analysis of the
three-dimensional structures of protein-DNA complexes now shows that the
binding of arginine residues to narrow minor grooves is a widely used
mode for protein-DNA recognition.
Remo Rohs et al.
doi:10.1038/nature08473
Abstract:
http://www.nature.com/nature/journal/v461/n7268/abs/nature08473.html
Article:
http://www.nature.com/nature/journal/v461/n7268/full/nature08473.html
----------------------
LETTERS
----------------------
A [ggr]-ray burst at a redshift of z[thinsp][ap][thinsp]8.2 pp1254-1257
Long-duration [gamma]-ray bursts (GRBs), thought to result from the
explosions
of certain massive stars, are bright enough that some of them should be
observable
out to redshifts of z > 20. So far, the highest redshift measured for any
object
has been z = 6.96, for a Lyman-[alpha] emitting galaxy. Here, and in an
accompanying paper, GRB 090423 is reported to lie at a redshift of z [ap] 8.
2,
implying that massive stars were being produced and dying as GRBs
approximately
620 million years after the Big Bang.
N. R. Tanvir et al.
doi:10.1038/nature08459
Abstract:
http://www.nature.com/nature/journal/v461/n7268/abs/nature08459.html
Article:
http://www.nature.com/nature/journal/v461/n7268/full/nature08459.html
GRB[thinsp]090423 at a redshift of z[thinsp][ap][thinsp]8.1 pp1258-1260
Long-duration [gamma]-ray bursts (GRBs), thought to result from the
explosions
of certain massive stars, are bright enough that some of them should be
observable out to redshifts of z > 20. So far, the highest redshift measured
for any object has been z = 6.96, for a Lyman-[alpha] emitting galaxy. Here,
and in an accompanying paper, GRB 090423 is reported to lie at a redshift of
z [ap] 8.2, implying that massive stars were being produced and dying as
GRBs
approximately 620 million years after the Big Bang.
R. Salvaterra et al.
doi:10.1038/nature08445
Abstract:
http://www.nature.com/nature/journal/v461/n7268/abs/nature08445.html
Article:
http://www.nature.com/nature/journal/v461/n7268/full/nature08445.html
Acceleration of neutral atoms in strong short-pulse laser
fields pp1261-1264
The force experienced by a charged particle in an oscillating electric field
is proportional to the cycle-averaged intensity gradient. This
'ponderomotive'
force plays a major part in a variety of physical situations. Extremely
strong
kinematic forces are now observed on neutral atoms in short-pulse laser
fields;
the ponderomotive force on electrons is identified as the driving mechanism,
leading to probably the highest observed acceleration on neutral atoms in an
external field to date.
U. Eichmann, T. Nubbemeyer, H. Rottke and W. Sandner
doi:10.1038/nature08481
Abstract:
http://www.nature.com/nature/journal/v461/n7268/abs/nature08481.html
Article:
http://www.nature.com/nature/journal/v461/n7268/full/nature08481.html
Preserving electron spin coherence in solids by optimal dynamical
decoupling
pp1265-1268
For the quantum coherence of electron spins in solid materials to be
exploited
in future technologies such as quantum computing, the problem of spin
decoherence
due to electron spins coupling to the noisy environment must first be
solved.
Here, pulsed electron paramagnetic resonance is used to demonstrate
experimentally
optimal dynamical decoupling for preserving electron spin coherence in
irradiated
malonic acid crystals at temperatures from 50 K to room temperature.
Jiangfeng Du et al.
doi:10.1038/nature08470
Abstract:
http://www.nature.com/nature/journal/v461/n7268/abs/nature08470.html
Article:
http://www.nature.com/nature/journal/v461/n7268/full/nature08470.html
A dearth of intermediate melts at subduction zone volcanoes and the
petrogenesis
of arc andesites pp1269-1273
A large proportion of the magmas erupted at continental arc volcanoes are
andesites, which are regarded as a major component in the formation of
continental crust - consequently, it is important to understand andesite
petrogenesis. Here, an alternative view of andesite petrogenesis is
presented,
based on a review of quenched glassy melt inclusions trapped in phenocrysts,
whole-rock chemistry, and high-pressure and high-temperature experiments;
this
new view resolves several puzzling aspects of arc volcanism.
Olivier Reubi and Jon Blundy
doi:10.1038/nature08510
Abstract:
http://www.nature.com/nature/journal/v461/n7268/abs/nature08510.html
Article:
http://www.nature.com/nature/journal/v461/n7268/full/nature08510.html
Visual but not trigeminal mediation of magnetic compass information in a
migratory bird pp1274-1277
How do birds find their way home? Magnetic compass information is known to
have a key role in bird orientation, but how birds are able to sense the
Earth's magnetic field remains unresolved, although two hypotheses have been
proposed [mdash] the iron-mineral-based hypothesis and the light-dependent
hypothesis. Here, reported data from European robins strongly suggest that a
vision-mediated mechanism underlies the magnetic compass in this migratory
songbird.
Manuela Zapka et al.
doi:10.1038/nature08528
Abstract:
http://www.nature.com/nature/journal/v461/n7268/abs/nature08528.html
Article:
http://www.nature.com/nature/journal/v461/n7268/full/nature08528.html
Regulation of cortical microcircuits by unitary GABA-mediated volume
transmission pp1278-1281
Excess neurotransmitter diffuses out of the synaptic cleft, where it can
activate neurotransmitter receptors outside the postsynaptic density.
However,
neurotransmitter reuptake is thought to limit the significance of such
extrasynaptic, or 'volume', transmission. Individual neurogliaform cells are
now shown to release enough GABA for volume transmission within the axonal
cloud; these cells do not require synapses to produce inhibitory responses
in nearby neurons.
Szabolcs Olah et al.
doi:10.1038/nature08503
Abstract:
http://www.nature.com/nature/journal/v461/n7268/abs/nature08503.html
Article:
http://www.nature.com/nature/journal/v461/n7268/full/nature08503.html
Regulation of inflammatory responses by gut microbiota and chemoattractant
receptor GPR43 pp1282-1286
Recent evidence indicates that normal intestinal microbiota may positively
influence immune responses and protect against the development of
inflammatory
diseases. One of the potential protective elements in this process are
short-chain fatty acids (SCFAs), which are produced by fermentation of
dietary
fibre by intestinal microbiota and bind the G-protein-coupled receptor 43
(GPR43). Here it is shown that SCFA-GPR43 interactions profoundly affect
inflammatory responses in mice.
Kendle M. Maslowski et al.
doi:10.1038/nature08530
Abstract:
http://www.nature.com/nature/journal/v461/n7268/abs/nature08530.html
Article:
http://www.nature.com/nature/journal/v461/n7268/full/nature08530.html
Resolvin D2 is a potent regulator of leukocytes and controls microbial
sepsis
pp1287-1291
Evidence indicates that resolution of acute inflammation is an active
process,
and resolvins - a family of lipid mediators enzymatically generated within
resolution networks - possess unique and specific functions to orchestrate
catabasis, the phase in which disease declines. Resolvin D2 is now shown to
reduce excessive neutrophil trafficking to inflammatory sites and to
decrease
leukocyte interactions with endothelial cells in a nitric-oxide-dependent
manner.
Matthew Spite et al.
doi:10.1038/nature08541
Abstract:
http://www.nature.com/nature/journal/v461/n7268/abs/nature08541.html
Article:
http://www.nature.com/nature/journal/v461/n7268/full/nature08541.html
Epigenetic reversion of post-implantation epiblast to pluripotent embryonic
stem
cells pp1292-1295
The pluripotent state is first established in the primitive ectoderm cells
of
blastocysts but is progressively and irreversibly lost during development.
For
example, the transition from primitive ectoderm cell to epiblast cell, post
implantation, involves significant transcriptional and epigenetic changes. A
technique for reprogramming advanced epiblast cells from embryonic day
5.5-7.5
mouse embryos to embryonic-stem-cell-like cells - representing a return to
pluripotency - is now demonstrated.
Siqin Bao et al.
doi:10.1038/nature08534
Abstract:
http://www.nature.com/nature/journal/v461/n7268/abs/nature08534.html
Article:
http://www.nature.com/nature/journal/v461/n7268/full/nature08534.html
A regulatory circuit for piwi by the large Maf gene traffic jam in
Drosophila
pp1296-1299
PIWI-interacting RNAs (piRNAs) are a class of small RNAs that are known to
associate with the PIWI proteins Argonaute 3, Aubergine and Piwi to silence
retrotransposons in Drosophila germ lines. However, the primary processing
pathway, one of two systems to produce piRNAs in Drosophila, remains
incompletely characterized. Primary piRNA processing in a Drosophila ovarian
somatic cell line is now analysed to reveal the large Maf gene traffic jam
as a new piRNA cluster.
Kuniaki Saito et al.
doi:10.1038/nature08501
Abstract:
http://www.nature.com/nature/journal/v461/n7268/abs/nature08501.html
Article:
http://www.nature.com/nature/journal/v461/n7268/full/nature08501.html
Exploitation of binding energy for catalysis and design pp1300-1304
Enzymes use substrate-binding energy to promote ground-state association and
to
selectively stabilize the reaction transition state. Mutations in the
amino-terminal domain of the monomeric homing endonuclease I-AniI, which
cleaves
with high sequence specificity in the centre of a 20-base-pair DNA target
site,
are now found to have different effects on the kinetic parameters of the
enzyme
than those in the carboxy-terminal domain, revealing an unexpected asymmetry
in
the use of enzyme-substrate binding energy for catalysis.
Summer B. Thyme et al.
doi:10.1038/nature08508
Abstract:
http://www.nature.com/nature/journal/v461/n7268/abs/nature08508.html
Article:
http://www.nature.com/nature/journal/v461/n7268/full/nature08508.html
----------------------
FUTURES
----------------------
Helpdesk p1312
Personal service.
rp g
doi:10.1038/4611312a
http://www.nature.com/nature/journal/v461/n7268/full/4611312a.html
Acceleration of neutral atoms in strong short-pulse laser fields
Nature杂志上1957年发表的一篇论文（http://tinyurl.com/kpfla4），描述了作用在
由关于洛伦兹电磁力的方程所产生的一个非均匀电场中带电粒子的一种力。研究人员很
快意识到，这种被称为“有质动力”的力有可能被用来束缚和控制电子。但是，这种力
很弱，而且直到现代激光出现之后，它才在粒子加速器和惯性约束聚变装置中得到利
用。现在，这种力的一种新的存在形式已经被发现。Ulrich Eichman等人对作用在短脉
冲激光场中的中性原子上的以前没有被人们考虑过的强运动力进行了观察。作用在电子
上的“有质动力”是它们的驱动机制，能造成中性原子的超强加速，加速作用比地球引
力加速大14个数量级。如此强的一种力可能导致基础物理和应用物理中新应用的问世。
本期封面所示为在与一个聚焦的激光束相互作用后中性氦原子所发生的偏移。（Letter
p. 1261）
地球上水的起源问题（Dry at first, wet later）
Volatile accretion history of the terrestrial planets and dynamic
implications
水是地球上的生物所必需的，所以有关我们的水是从哪里来的问题是一个人们相当感兴
趣的问题。Francis Albarede对有关下面这个假设的证据进行了分析：在导致月球形成
的巨大碰撞发生之时，撞击的天体和原始地球基本上都是干的，只是在过了很长时间之
后通过从小行星带不断吸积湿的东西才获得了挥发性物质。他的结论是，这种水向地幔
中的引入可能触发了板块构造，而且这一机制对年轻的金星也可能曾发挥过作用，但对
火星似乎未能起作用。（Progress p. 1227）这篇论文是我们“国际天文年”纪念活动
系列文章之一，也发布在http://tinyurl.com/prhcqy上。
核糖体结构和功能研究方面的最新进展（Ribosomes in translation）
What recent ribosome structures have revealed about the mechanism of
translation
在一篇恰逢其时的“Review”文章中，2009年诺贝尔化学奖得主之一的Venkatraman
Ramakrishnan及其同事Martin Schmeing，对有关核糖体结构和功能研究方面的最新进
展进行了综述。以细菌转录的主要方面（这些方面对于所有蛋白的合成都应是共同的）
为重点，他们介绍了有关核糖体结构的知识是怎样越来越多地推动着复杂的生物化学和
遗传学实验工作。除了对基础转录研究的影响外，细菌结构知识还为开发更好的抗生素
提供了一个框架。（Review p. 1234）关于对Venkatraman Ramakrishnan的视频访谈，
请访问Nature Video YouTube频道，网址为：
www.youtube.com/user/NatureVideoChannel。
基因组演化的速度和模式（The generation game）
Genome evolution and adaptation in a long-term experiment with Escherichia
coli
在一项实验中，研究人员在实验室中培养了一批大肠杆菌，它们在近20年时间里一直以
葡萄糖为一种限制性营养物。这项实验为研究基因组演化的速度和模式提供了一个机
会。大肠杆菌克隆的基因组分别在2,000代、5,000代、10,000代、15,000代、20,000代
和 40,000代后被取样。适应性的发展加速极快，但基因组演化在20,000代几乎是不变
的。这样的一致性被认为是中性演化的特点，但来自几个方面的证据都表明，这些突变
大部分都是有益的。这个种群后来突变速度加快，并且积累了数百个另外的、以中性为
特征的突变。显然，基因组演化和适应性演化之间的耦合是一个复杂的问题。
（Article p. 1243; News & Views）
序列特异性DNA结合蛋白寻找目标的方式（Major to minor）
The role of DNA shape in protein–DNA recognition
序列特异性DNA结合蛋白何以能在数量巨大的非特异性DNA中找到目标是一个长期未解之
谜。一个比较受欢迎的模型是，序列是作为DNA螺旋的“大沟”中蛋白与碱基之间氢键
的形成被读取的。对蛋白-DNA复合物三维结构所做的一项新的分析表明，DNA形状是识
别的关键。DNA序列的前后部分通过让精氨酸优先与带负电的“口袋”结合改变DNA螺旋
“小沟”的宽度。DNA在核小体核心颗粒中的定位是这一效应的一个例子。（Article
p. 1248; News & Views）
伽马射线暴GRB 090423的红移值（Bursting at high redshift）
A -ray burst at a redshift of z 8.2 / GRB 090423 at a redshift of z 8.1
两个小组在本期Nature上发表了伽马射线暴GRB 090423的红移值和其他光谱数据。
Savaterra等人报告了其由Swift卫星在2009年4月23日获得的最初探测结果，以及在该
伽马射线暴发生14小时之后由位于La Palma的伽利略国家望远镜进行的一次红移测定，
所得值为z = 8.1。Tanvir等人利用位于夏威夷的英国红外天文望远镜在该伽马射线暴
发生约20分钟之后进行了红移测定，所得值为z = 8.1。 这些红移值与以前获得的任何
一个天体的已知最高红移值形成对比，后者为z = 6.96，是一个发射Lyman-α的星系的
红移值。这些测量值意味着，早在“大爆炸”之后约6亿年，大质量恒星就在随着伽马
射线暴的发生而生成和死亡，而且它们的性质与100亿年之后产生伽马射线暴的那些恒
星非常相似。（Letters pp. 1254, 1258; News & Views）
减小电子自旋与其环境相互作用噪音的方式（Tone down the noise）
Preserving electron spin coherence in solids by optimal dynamical decoupling
如果固体物质中的电子自旋要在量子计算机中得到利用，就需要减小不可避免会随自旋
与其环境相互作用出现的量子“噪音”。 现在，在发生脉冲式电子顺磁共振的丙二酸
单晶中所做的实验表明，这是可以做到的。利用外部脉冲诱导电子自旋去“翻转”最佳
的次数，会使其与环境相互作用所产生的噪音均匀化至零，而且自旋相干性所维持的时
间尺度也得到显著增加——在所研究的体系中从0.04 微秒增加到了30微秒。（Letter
p. 1265; News & Views）
鸟类磁定向能力与其眼睛有关（Bird navigation: the eyes have it）
Visual but not trigeminal mediation of magnetic compass information in a
migratory bird
鸟儿怎样找到回家的路？所有人都同意动物能够利用地球磁场来形成一个体内“罗盘”
以感应方向的说法，但人们观点的一致性也就到此为止。一些研究人员提出这样一个观
点：磁性是由鸟喙中连接到三叉神经上的磁体来探测的；另一些研究人员则认为，磁性
是通过眼睛经由一个复杂的光敏机制来传导的。对后一个观点（即有关眼睛所起作用的
观点）的支持，来自对欧洲知更鸟的一项神经外科和行为学研究。在脑中一个被称为
“cluster N”的中心有病灶的鸟被发现缺乏磁定向能力。而且至少在这种候鸟中，其
喙中假设存在的磁受体在磁性罗盘定向中没有起作用。（Letter p. 1274）
宿主-细菌相互作用现象（Host–bacteria phenomena）
Regulation of inflammatory responses by gut microbiota and chemoattractant
receptor GPR43 / Resolvin D2 is a potent regulator of leukocytes and
controls microbial sepsis
本期Nature上两篇论文凸显了有关小肠细菌与其宿主相互作用的研究工作的价值。最新
证据表明，小肠有益菌的产物能抵抗炎症和I-型糖尿病。结肠中的共生菌已知能发酵食
物纤维产生短链脂肪酸，而现在对一个小鼠结肠炎模型所做的一项研究表明，这些脂肪
酸能够通过刺激嗜中性细胞上的化学吸引剂受体GPR43来抑制先天性和炎性反应。这说
明短链脂肪酸与GPR43之间的相互作用为操控免疫反应的一个可能的目标。（Letter p.
1282）来自omega-3脂肪酸的局部发挥作用的Resolvins已被发现是消炎调控因子。现
在，对一个小鼠腹腔脓毒症模型所做研究表明，Resolvin D2 (RvD2)抑制嗜中性细胞向
发炎处的运送，降低白细胞与内皮细胞的相互作用。RvD2的细胞和分子作用转变成急剧
增加的存活率。这一发现表明，RvD2是一种强效消炎药物，同时也提出了不会降低宿主
防卫能力的新治疗方法。（Letter p. 1287）
外胚层细胞重新获得多能性的方式（Epiblasts regain pluripotency）
Epigenetic reversion of post-implantation epiblast to pluripotent embryonic
stem cells
首次在囊胚期胚胎的原始外胚层细胞中形成的多能状态，在随后的发育中会失去。现
在，Bao等人发现，来自形成时间已长达7.5天的小鼠胚胎的高级植入后外胚层细胞，可
通过暴露于LIF/STAT3信号作用而被重新编程回到多能状态。它们在转录组（细胞中的
全部mRNA）中发现了伴随的变化，这些变化导致见于外胚层细胞中的表型记忆和外遗传
记忆的丧失。以这种方式重新编程的细胞会形成银鲛的体细胞组织和生殖细胞，与能够
自我更新的外胚层干细胞不同。这项工作为研究信号作用和外遗传重新编程会怎样促进
多能性的重新获得提供了一个模型。（Letter p. 1292）
利用酶基质结合能进行催化方面的非对称性（Enzyme catalysis）
Exploitation of binding energy for catalysis and design
酶利用基质结合能来促进基态结合和选择性地降低反应过渡态的能量。Thyme等人已确
定，对单体“归巢”核酸内切酶I-AniI（该酶能以高序列特异性分解双链DNA）来说，
这种酶的N-端区域的突变造成某些运动参数（KA 和 KM）增加，而C-端区域的突变则减
小另一运动参数（kcat）。在利用酶基质结合能进行催化方面的这一出乎意料的非对称
性，也许使研究人员能够更有效地重新设计核酸内切酶，来分解基因组目标点，用于基
因疗法和其他生物医学应用。（Letter p. 1300）
----------------------
NEWS AND VIEWS
----------------------
Quantum information: Caught at the finishing line pp1217-1218
Quantum systems habitually leak information, limiting their usefulness
for practical applications. By optimally reversing the leak, this
information loss has been reduced to a trickle in the solid state.
Bob B. Buckley and David D. Awschalom
doi:10.1038/4611217a
http://www.nature.com/nature/journal/v461/n7268/full/4611217a.html
Materials science: Emerging routes to multiferroics pp1218-1219
Materials that combine ferroic properties [mdash] such as ferromagnetism
and ferroelectricity [mdash] are highly desirable, but rare. A new class
of multiferroic solids heralds a fresh approach for making such materials.
Ramamoorthy Ramesh
doi:10.1038/4611218a
http://www.nature.com/nature/journal/v461/n7268/full/4611218a.html
Evolutionary biology: Arrhythmia of tempo and mode pp1219-1221
An exercise in experimental evolution using bacteria has been running for
more than 20 years and 40,000 generations. The results to date provide
a glimpse of a new world, and are cause for both delight and unease.
Paul B. Rainey
doi:10.1038/4611219a
http://www.nature.com/nature/journal/v461/n7268/full/4611219a.html
Astrophysics: Most distant cosmic blast seen pp1221-1223
The most distant [gamma]-ray burst yet sighted is the earliest astronomical
object ever observed in cosmic history. This ancient beacon offers a
glimpse of the little-known cosmic dark ages.
Bing Zhang
doi:10.1038/4611221a
http://www.nature.com/nature/journal/v461/n7268/full/4611221a.html
Catalysis: Bond control in surface reactions pp1223-1225
Catalysts steer reactions towards certain products [mdash] but the basis
of their control is often unclear. Quantum chemical calculations reveal
which parameters control bond formation in a network of catalytic reactions.
Jens K. Norskov and Frank Abild-Pedersen
doi:10.1038/4611223a
http://www.nature.com/nature/journal/v461/n7268/full/4611223a.html
Structural biology: DNA binding shapes up pp1225-1226
DNA-binding proteins have the daunting task of finding their binding sites
among the 3 billion base pairs of the human genome. The shape of DNA, and
not just its sequence, may offer proteins much-needed direction.
Tom Tullius
doi:10.1038/4611225a
http://www.nature.com/nature/journal/v461/n7268/full/4611225a.html
Statistical physics: Swirled by light p1226
A micrometre-sized particle immersed in a liquid can be trapped by light.
An experiment shows that the trapping can be accompanied by a whirling
whose direction can be reversed by changing the light intensity.
Mark I. Dykman
doi:10.1038/4611226a
http://www.nature.com/nature/journal/v461/n7268/full/4611226a.html
----------------------
PROGRESS
----------------------
Volatile accretion history of the terrestrial planets and dynamic
implications pp1227-1233
Francis Albarede
doi:10.1038/nature08477
Abstract:
http://www.nature.com/nature/journal/v461/n7268/abs/nature08477.html
Article:
http://www.nature.com/nature/journal/v461/n7268/full/nature08477.html
----------------------
REVIEW
----------------------
What recent ribosome structures have revealed about the mechanism of
translation pp1234-1242
T. Martin Schmeing and V. Ramakrishnan
doi:10.1038/nature08403
Abstract:
http://www.nature.com/nature/journal/v461/n7268/abs/nature08403.html
Article:
http://www.nature.com/nature/journal/v461/n7268/full/nature08403.html
----------------------
ARTICLES
----------------------
Genome evolution and adaptation in a long-term experiment with
Escherichia coli pp1243-1247
Here, in order to gain insight into the relationship between rates of
genomic evolution and organismal adaptation, genomes sampled through 40,000
generations are sequenced from a laboratory population of Escherichia coli.
The results indicate that the coupling between genomic and adaptive
evolution
is complex and can be counterintuitive even in a constant environment, with
beneficial mutations surprisingly uniform over time whereas neutral
substitutions were highly variable.
Jeffrey E. Barrick et al.
doi:10.1038/nature08480
Abstract:
http://www.nature.com/nature/journal/v461/n7268/abs/nature08480.html
Article:
http://www.nature.com/nature/journal/v461/n7268/full/nature08480.html
The role of DNA shape in protein-DNA recognition pp1248-1253
The question of how proteins recognize specific DNA sequences in the face of
vastly higher concentrations of non-specific DNA remains unclear. One
suggested mechanism involves the formation of hydrogen bonds with specific
bases, primarily in the major groove. The comprehensive analysis of the
three-dimensional structures of protein-DNA complexes now shows that the
binding of arginine residues to narrow minor grooves is a widely used
mode for protein-DNA recognition.
Remo Rohs et al.
doi:10.1038/nature08473
Abstract:
http://www.nature.com/nature/journal/v461/n7268/abs/nature08473.html
Article:
http://www.nature.com/nature/journal/v461/n7268/full/nature08473.html
----------------------
LETTERS
----------------------
A [ggr]-ray burst at a redshift of z[thinsp][ap][thinsp]8.2 pp1254-1257
Long-duration [gamma]-ray bursts (GRBs), thought to result from the
explosions
of certain massive stars, are bright enough that some of them should be
observable
out to redshifts of z > 20. So far, the highest redshift measured for any
object
has been z = 6.96, for a Lyman-[alpha] emitting galaxy. Here, and in an
accompanying paper, GRB 090423 is reported to lie at a redshift of z [ap] 8.
2,
implying that massive stars were being produced and dying as GRBs
approximately
620 million years after the Big Bang.
N. R. Tanvir et al.
doi:10.1038/nature08459
Abstract:
http://www.nature.com/nature/journal/v461/n7268/abs/nature08459.html
Article:
http://www.nature.com/nature/journal/v461/n7268/full/nature08459.html
GRB[thinsp]090423 at a redshift of z[thinsp][ap][thinsp]8.1 pp1258-1260
Long-duration [gamma]-ray bursts (GRBs), thought to result from the
explosions
of certain massive stars, are bright enough that some of them should be
observable out to redshifts of z > 20. So far, the highest redshift measured
for any object has been z = 6.96, for a Lyman-[alpha] emitting galaxy. Here,
and in an accompanying paper, GRB 090423 is reported to lie at a redshift of
z [ap] 8.2, implying that massive stars were being produced and dying as
GRBs
approximately 620 million years after the Big Bang.
R. Salvaterra et al.
doi:10.1038/nature08445
Abstract:
http://www.nature.com/nature/journal/v461/n7268/abs/nature08445.html
Article:
http://www.nature.com/nature/journal/v461/n7268/full/nature08445.html
Acceleration of neutral atoms in strong short-pulse laser
fields pp1261-1264
The force experienced by a charged particle in an oscillating electric field
is proportional to the cycle-averaged intensity gradient. This
'ponderomotive'
force plays a major part in a variety of physical situations. Extremely
strong
kinematic forces are now observed on neutral atoms in short-pulse laser
fields;
the ponderomotive force on electrons is identified as the driving mechanism,
leading to probably the highest observed acceleration on neutral atoms in an
external field to date.
U. Eichmann, T. Nubbemeyer, H. Rottke and W. Sandner
doi:10.1038/nature08481
Abstract:
http://www.nature.com/nature/journal/v461/n7268/abs/nature08481.html
Article:
http://www.nature.com/nature/journal/v461/n7268/full/nature08481.html
Preserving electron spin coherence in solids by optimal dynamical
decoupling
pp1265-1268
For the quantum coherence of electron spins in solid materials to be
exploited
in future technologies such as quantum computing, the problem of spin
decoherence
due to electron spins coupling to the noisy environment must first be
solved.
Here, pulsed electron paramagnetic resonance is used to demonstrate
experimentally
optimal dynamical decoupling for preserving electron spin coherence in
irradiated
malonic acid crystals at temperatures from 50 K to room temperature.
Jiangfeng Du et al.
doi:10.1038/nature08470
Abstract:
http://www.nature.com/nature/journal/v461/n7268/abs/nature08470.html
Article:
http://www.nature.com/nature/journal/v461/n7268/full/nature08470.html
A dearth of intermediate melts at subduction zone volcanoes and the
petrogenesis
of arc andesites pp1269-1273
A large proportion of the magmas erupted at continental arc volcanoes are
andesites, which are regarded as a major component in the formation of
continental crust - consequently, it is important to understand andesite
petrogenesis. Here, an alternative view of andesite petrogenesis is
presented,
based on a review of quenched glassy melt inclusions trapped in phenocrysts,
whole-rock chemistry, and high-pressure and high-temperature experiments;
this
new view resolves several puzzling aspects of arc volcanism.
Olivier Reubi and Jon Blundy
doi:10.1038/nature08510
Abstract:
http://www.nature.com/nature/journal/v461/n7268/abs/nature08510.html
Article:
http://www.nature.com/nature/journal/v461/n7268/full/nature08510.html
Visual but not trigeminal mediation of magnetic compass information in a
migratory bird pp1274-1277
How do birds find their way home? Magnetic compass information is known to
have a key role in bird orientation, but how birds are able to sense the
Earth's magnetic field remains unresolved, although two hypotheses have been
proposed [mdash] the iron-mineral-based hypothesis and the light-dependent
hypothesis. Here, reported data from European robins strongly suggest that a
vision-mediated mechanism underlies the magnetic compass in this migratory
songbird.
Manuela Zapka et al.
doi:10.1038/nature08528
Abstract:
http://www.nature.com/nature/journal/v461/n7268/abs/nature08528.html
Article:
http://www.nature.com/nature/journal/v461/n7268/full/nature08528.html
Regulation of cortical microcircuits by unitary GABA-mediated volume
transmission pp1278-1281
Excess neurotransmitter diffuses out of the synaptic cleft, where it can
activate neurotransmitter receptors outside the postsynaptic density.
However,
neurotransmitter reuptake is thought to limit the significance of such
extrasynaptic, or 'volume', transmission. Individual neurogliaform cells are
now shown to release enough GABA for volume transmission within the axonal
cloud; these cells do not require synapses to produce inhibitory responses
in nearby neurons.
Szabolcs Olah et al.
doi:10.1038/nature08503
Abstract:
http://www.nature.com/nature/journal/v461/n7268/abs/nature08503.html
Article:
http://www.nature.com/nature/journal/v461/n7268/full/nature08503.html
Regulation of inflammatory responses by gut microbiota and chemoattractant
receptor GPR43 pp1282-1286
Recent evidence indicates that normal intestinal microbiota may positively
influence immune responses and protect against the development of
inflammatory
diseases. One of the potential protective elements in this process are
short-chain fatty acids (SCFAs), which are produced by fermentation of
dietary
fibre by intestinal microbiota and bind the G-protein-coupled receptor 43
(GPR43). Here it is shown that SCFA-GPR43 interactions profoundly affect
inflammatory responses in mice.
Kendle M. Maslowski et al.
doi:10.1038/nature08530
Abstract:
http://www.nature.com/nature/journal/v461/n7268/abs/nature08530.html
Article:
http://www.nature.com/nature/journal/v461/n7268/full/nature08530.html
Resolvin D2 is a potent regulator of leukocytes and controls microbial
sepsis
pp1287-1291
Evidence indicates that resolution of acute inflammation is an active
process,
and resolvins - a family of lipid mediators enzymatically generated within
resolution networks - possess unique and specific functions to orchestrate
catabasis, the phase in which disease declines. Resolvin D2 is now shown to
reduce excessive neutrophil trafficking to inflammatory sites and to
decrease
leukocyte interactions with endothelial cells in a nitric-oxide-dependent
manner.
Matthew Spite et al.
doi:10.1038/nature08541
Abstract:
http://www.nature.com/nature/journal/v461/n7268/abs/nature08541.html
Article:
http://www.nature.com/nature/journal/v461/n7268/full/nature08541.html
Epigenetic reversion of post-implantation epiblast to pluripotent embryonic
stem
cells pp1292-1295
The pluripotent state is first established in the primitive ectoderm cells
of
blastocysts but is progressively and irreversibly lost during development.
For
example, the transition from primitive ectoderm cell to epiblast cell, post
implantation, involves significant transcriptional and epigenetic changes. A
technique for reprogramming advanced epiblast cells from embryonic day
5.5-7.5
mouse embryos to embryonic-stem-cell-like cells - representing a return to
pluripotency - is now demonstrated.
Siqin Bao et al.
doi:10.1038/nature08534
Abstract:
http://www.nature.com/nature/journal/v461/n7268/abs/nature08534.html
Article:
http://www.nature.com/nature/journal/v461/n7268/full/nature08534.html
A regulatory circuit for piwi by the large Maf gene traffic jam in
Drosophila
pp1296-1299
PIWI-interacting RNAs (piRNAs) are a class of small RNAs that are known to
associate with the PIWI proteins Argonaute 3, Aubergine and Piwi to silence
retrotransposons in Drosophila germ lines. However, the primary processing
pathway, one of two systems to produce piRNAs in Drosophila, remains
incompletely characterized. Primary piRNA processing in a Drosophila ovarian
somatic cell line is now analysed to reveal the large Maf gene traffic jam
as a new piRNA cluster.
Kuniaki Saito et al.
doi:10.1038/nature08501
Abstract:
http://www.nature.com/nature/journal/v461/n7268/abs/nature08501.html
Article:
http://www.nature.com/nature/journal/v461/n7268/full/nature08501.html
Exploitation of binding energy for catalysis and design pp1300-1304
Enzymes use substrate-binding energy to promote ground-state association and
to
selectively stabilize the reaction transition state. Mutations in the
amino-terminal domain of the monomeric homing endonuclease I-AniI, which
cleaves
with high sequence specificity in the centre of a 20-base-pair DNA target
site,
are now found to have different effects on the kinetic parameters of the
enzyme
than those in the carboxy-terminal domain, revealing an unexpected asymmetry
in
the use of enzyme-substrate binding energy for catalysis.
Summer B. Thyme et al.
doi:10.1038/nature08508
Abstract:
http://www.nature.com/nature/journal/v461/n7268/abs/nature08508.html
Article:
http://www.nature.com/nature/journal/v461/n7268/full/nature08508.html
----------------------
FUTURES
----------------------
Helpdesk p1312
Personal service.
rp g
doi:10.1038/4611312a
http://www.nature.com/nature/journal/v461/n7268/full/4611312a.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 |
特别声明：本文转载仅仅是出于传播信息的需要，版权归原作者所有，并不意味着代表本网站观点或证实其内容的真实性； 如其他媒体、网站或个人从本网站转载使用，须保留本网站注明的“来源”，并自负版权等法律责任； 作者如果不希望被转载或者联系转载稿费等事宜，请与我们接洽：service#environmentor.cn（请将#改为@）。
来源： 作者： （环境人 Environmentor.Cn）
