《Nature》目录要览：2010-02-05出版
时间：2010-02-08 阅读： 我要评论:
《Nature》目录要览：2010-02-05出版
封面故事：雾气中的蜘蛛网
Directional water collection on wetted spider silk
在有雾的早晨，蜘蛛网会闪闪发光，这表明它们能以很高效率从潮湿空气中收集水滴。
对草间蜘蛛（Uloborus walckenaerius）的网所做的一项研究显示，这种能力取决于蜘
蛛网湿了之后所发生的一个结构变化。“湿后重构”的纤维以周期性纺锤节为特征，后
者由随机的纳米纤维构成，被排列整齐的纳米纤维结点分隔开。这种结构在纺锤节和结
点之间产生一个表面能量梯度，并在作用在与纺锤节或结点相接触的水滴上的压力上产
生一个差别。这样可以确保水能在结点周围不断凝结，然后被输送到纺锤节上，在那里
它能积聚成悬挂起来的大水滴，如本期封面所示。模仿变湿的蛛丝结构的一种人造丝也
能从薄雾中收集水滴。这项研究对于设计能从雾气中收集淡水或在工业过程中过滤液体
气溶胶的功能性表面的工作可能会有启发。（Letter p. 640）
支配细胞命运的机制（Cell fate in the balance）
Opposing microRNA families regulate self-renewal in mouse embryonic stem
cells
胚胎干细胞的分化既需要对自我更新进行抑制，又需要对一个特定的分化通道进行激
发。被称为微RNA（miRNA）的小型非编码RNA作为支配细胞命运的重要物质正在被人们
所认识。现在研究发现，一种名为“let-7”的著名miRNA负责抑制胚胎干细胞中的自我
更新程序。这种抑制可以被一组“胚胎干细胞调控型miRNA”（称之为ESCC miRNA，它
们调控细胞周期）逆转，说明“let-7”和ESCC miRNA之间的互动提供一个能够支配细
胞命运的机制。（Article p. 621; News & Views）
蛋白酶抗疟疾目标（Protease antimalarial target）
An aspartyl protease directs malaria effector proteins to the host cell /
Plasmepsin V licenses Plasmodium proteins for export into the host
erythrocyte
疟原虫生命周期的一个关键部分（也是使通过蚊子向其他宿主传播疟疾成为可能的一个
部分）涉及在宿主血红细胞内的一个生长阶段。在这个阶段，疟原虫细胞将几百种蛋白
输出到宿主血细胞中，它们会将宿主血细胞改造成一个适合疟原虫繁殖的环境。注定要
被输出的蛋白包含一个保守主题，即PEXEL，而当这个主题在内质网中被分解之后，蛋
白便能转位到宿主细胞中。现在，两项独立的研究工作显示，分解PEXEL主题的酶为门
冬氨酰蛋白酶“plasmepsin V”。这一发现的直接意义是，它表明“plasmepsin V”是
抗疟疾药物的一个潜在作用目标。（Articles pp. 627, 632）
太阳系外行星大气层的地基观测研究（Exoplanet atmospheres）
A ground-based near-infrared emission spectrum of the exoplanet HD?189733b
空间红外光谱仪器已在被称为“热木星”的太阳系外行星的大气中成功识别出了H2O、
CH4、CO2 和 CO等各种不同分子。现在Swain等人报告了在太空望远镜无法观测的近红
外波长对“热木星”HD 189733b的光面发射光谱所做的基于地面的观测研究。他们在约
3.25μm处发现了一个明亮的发射特征，该特征利用假设局部热动态平衡条件的当前模
型是不能预测到和难以解释的。来自甲烷的荧光发射（与在太阳系行星大气中所看到的
相似）似乎是一个可能的解释。这项工作表明太阳系外行星上的大气化学要比以前所想
的更复杂，同时它也将太阳系外行星分子光谱学研究领域向地基望远镜敞开了大门。
（Letter p. 637; News & Views）
光合作用中的量子效应（Wired for light）
Coherently wired light-harvesting in photosynthetic marine algae at ambient
temperature
光合作用中最令人着迷、被研究最多的特征之一是能量在光合作用复合物中进行传输的
极高效率。一项新的光谱研究，通过直接显示室温下在来自Chroomonas CCMP270海藻的
5-纳米宽的光合作用蛋白上电子激发的量子相干共享，证实了人们早先提出的量子效应
可能在其中发挥作用的暗示。观察表明，这些蛋白内相距较远的单元被量子相干连接在
一起，以增强集光效率。（Letter p. 644; News & Views）
圣安德烈斯断层地震发生带下的形变过程（San Andreas tremors）
Migrating tremors illuminate complex deformation beneath the seismogenic San
Andreas fault
尽管人们已经进行了广泛研究，但关于圣安德烈斯断层地震发生带下的形变过程仍然有
很多东西有待发现。现在，美国地质调查局的David Shelly报告了对从2001年年中到
2008年观察到的地震情况所做的一项分析，他采用的方法所能达到的时空分辨率高于以
前在该地区所能达到的程度。其分析显示，圣安德烈斯断层在帕克菲尔德附近是地壳底
部一个连续结构，同时它也揭示了在地震发生带下的那部分断层上的人们以前不知道
的、复杂的形变模式，其中包括以高达每小时80公里速度迁移的震动序列。（Letter
p. 648）
马达加斯加的哺乳动物最初乘木筏而来（Madagascar ahoy）
Mammalian biodiversity on Madagascar controlled by ocean currents
马达加斯加有一个非常引人瞩目而又非常奇特的动物区系。虽然马达加斯加的哺乳动物
与非洲哺乳动物有远亲关系，但它们显然已经孤立进化了数千万年。它们的祖先是怎样
到该岛上的？1940年，杰出的古生物学家George Gaylord Simpson提出，哺乳动物是乘
坐木筏随波逐流从非洲到达那里的，这就是所谓的“Sweepstakes”假说。这个假说可
解释本地动物区系的古怪特点——只不过洋流是向相反方向流的，即是朝着非洲方向
的，而不是远离非洲方向的。但认为马达加斯加和非洲大陆陆地直接相连的另一种解释
也被排除了，因为马达加斯加在哺乳动物开始它们演化旅程时是一个岛屿。Jason Ali
和 Matthew Huber提出了解决这一问题的一个办法：对始新世（距今超过5000万年前）
时的洋流所做的一项重建工作表明，在一段短暂的时期内，洋流的确是从西向东流的，
从而使得动物能够通过木筏到马达加斯加定居。（Letter p. 653; News & Views）
人类与老鼠的共同之处（On the grid for the rat race）
Evidence for grid cells in a human memory network
Edvard Moser及其同事发现，大鼠和小鼠拥有关于它们周围环境的一个方向图，是由被
称为“网格细胞”的大脑皮层神经元产生和更新的。该发现是近年来最为激动人心的神
经科学发现之一。这些细胞为自我定位提供了一个周期性非常强的表述。这便自然引出
一个问题：人类是否也有一个类似机制？Christian Doeller、Caswell Barry 和 Neil
Burgess的一篇论文为这个问题提供了答案。在这项研究中，他们将自由运动大鼠网格
细胞的单元记录与在虚拟环境中穿行的人的全脑磁共振成像（fMRI）结合在了一起。
Doeller等人能够检测到代表一个人在虚拟现实环境中位置的宏观fMRI信号，该信号符
合定义网格细胞编码的标准。所以，人类似乎是用一种与啮齿类动物非常像的方式来表
示位置和支持空间认知的。（Letter p. 657）
导致肥胖症的基因突变（Genetic link to obesity）
Large, rare chromosomal deletions associated with severe early-onset obesity
/ A new highly penetrant form of obesity due to deletions on chromosome
16p11.2
肥胖症是一种具有高度遗传性的疾病，但迄今所报告的遗传关联性只能解释身体质量指
数遗传变化的很小一部分。两个小组报告了染色体16p11.2上所发生的基因删除，它们
也许可解释所谓“高外显率”突变中部分“缺失的遗传性”。这类突变很罕见，但一旦
存在，就会以非常高的频率被与严重肥胖症联系起来。这跟与临床症候联系不是很密切
的更为常见的基因缺陷形成对比。Bochukova等人在300个患有严重早发性肥胖周的患者
身上发现了罕见的复发性版本数突变体，它们是由涉及包括SH2B1（已知参与“莱普
亭”和胰岛素的信号作用）在内的几种基因的删除造成的。这些患者很多还患有神经发
育症。Walters等人在31个患有一种以前未被识别出的极端肥胖症的患者的染色体
16p11.2上识别出至少593个千碱基对的删除。他们用来识别病灶的策略（利用数量较少
的、表现型较好的极端表现型人群进行研究，继之以定向全基因组关联研究和
“population cohort”研究）有望作为一种手段，来识别更具普遍性的复杂代谢疾病
中“缺失的遗传性”。（Letters pp. 666, 671）
流感病毒蛋白的两面性（Double life of flu virus protein）
Structure of the amantadine binding site of influenza M2 proton channels in
lipid bilayers
当前的H1N1流感病毒对成熟的抗病毒药物金刚胺和金刚乙胺有抵抗力。这两种药物以M2
蛋白为作用目标，该蛋白是一种多功能跨膜质子通道。这个通道的结构一直是一个有些
争议的话题，因为M2通道一部分的X-射线晶体结构所显示的电子密度相应于微孔N-端那
一部分的单一金刚胺分子，而该通道更大一部分的溶液NMR结构则显示有四个金刚乙胺
分子结合到螺旋体C-端朝向类脂的表面上。现在，随着处在一个磷脂双层中的M2通道的
高分辨率结构（该结构利用固态NMR光谱获得）的发表，这个问题似乎已经解决。该结
构显示金刚胺有两个结合点：N-端通道腔中一个高亲和度点和C-端蛋白表面上一个低亲
和度点。这项工作对于新兴抗流感药物的开发可能会有价值（这是一个重要目标，因为
2009年的季节性流感病毒对金刚胺是敏感的，但对“达菲”（Tamiflu）却有抵抗
力），这便提出一个可能性：将来可能会出现多种抗药性病毒类型。（Letter p.
689）
----------------------
NEWS AND VIEWS
----------------------
Biogeography: Washed up in Madagascar pp613-614
How, when and from where did Madagascar's unique mammalian fauna originate?
The idea that the ancestors of that fauna rafted from Africa finds support
in innovative simulations of ancient ocean currents.
David W. Krause
doi:10.1038/463613a
http://www.nature.com/nature/journal/v463/n7281/full/463613a.html
Photosynthesis: Quantum design for a light trap pp614-615
The photosynthetic apparatus of cryptophyte algae is odd - its pigments are
farther apart than is expected for efficient functioning. A study into how
this apparatus works so well finds quantum effects at play.
Rienk van Grondelle and Vladimir I. Novoderezhkin
doi:10.1038/463614a
http://www.nature.com/nature/journal/v463/n7281/full/463614a.html
Stem cells: Big roles for small RNAs p616
Embryonic stem cells can create copies of themselves, but can also mature
into almost any type of cell in the body. Tiny gene regulators called
microRNAs are now shown to have a role in directing these properties.
Frank J. Slack
doi:10.1038/463616a
http://www.nature.com/nature/journal/v463/n7281/full/463616a.html
50 & 100 years ago p617
doi:10.1038/463617b
http://www.nature.com/nature/journal/v463/n7281/full/463617b.html
Extrasolar planets: Fluorescent methane spotted pp617-618
The atmospheric properties of distant worlds are becoming increasingly
clear. The latest observations reveal fluorescent emission from methane in
the upper atmosphere of a Jupiter-like extrasolar planet.
Seth Redfield
doi:10.1038/463617a
http://www.nature.com/nature/journal/v463/n7281/full/463617a.html
Biomaterials: Dew catchers p618
Magdalena Helmer
doi:10.1038/463618a
http://www.nature.com/nature/journal/v463/n7281/full/463618a.html
Applied physics: Nanothermal trumpets p619
The thermal process known as Joule heating, which often plagues electronic
devices, has been turned to good use: making devices that can produce sound
as well as reproduce music and speech.
Rama Venkatasubramanian
doi:10.1038/463619a
http://www.nature.com/nature/journal/v463/n7281/full/463619a.html
----------------------
ARTICLES
----------------------
Opposing microRNA families regulate self-renewal in mouse embryonic stem
cells pp621-626
The differentiation of an embryonic stem cell (ESC) requires both
suppression of the self-renewal process and activation of the specific
differentiation pathway. The let-7 family of microRNAs (miRNAs) are now
shown to suppress the self-renewal program in cells that are normally unable
to silence this program, whereas introduction of ESC cell cycle regulating
miRNAs blocks the action of let-7. Thus, the interplay between these two
groups of miRNAs dictates cell fate.
Collin Melton, Robert L. Judson and Robert Blelloch
doi:10.1038/nature08725
Abstract:
http://www.nature.com/nature/journal/v463/n7281/abs/nature08725.html
Article:
http://www.nature.com/nature/journal/v463/n7281/full/nature08725.html
An aspartyl protease directs malaria effector proteins to the host
cell pp627-631
To survive and evade host responses, malaria parasites export several
hundred proteins into the host cell on infection. A feature of these
proteins is a conserved, pentameric motif that is cleaved by an unknown
protease before export. This is one of two independent studies revealing the
identity of the protease as plasmepsin V, an aspartic acid protease located
in the endoplasmic reticulum. This enzyme is essential for parasite
viability and is an attractive candidate for drug development.
Justin A. Boddey et al.
doi:10.1038/nature08728
Abstract:
http://www.nature.com/nature/journal/v463/n7281/abs/nature08728.html
Article:
http://www.nature.com/nature/journal/v463/n7281/full/nature08728.html
Plasmepsin V licenses Plasmodium proteins for export into the host
erythrocyte pp632-636
To survive and evade host responses, malaria parasites export several
hundred proteins into the host cell on infection. A feature of these
proteins is a conserved, pentameric motif that is cleaved by an unknown
protease before export. This is one of two independent studies revealing the
identity of the protease as plasmepsin V, an aspartic acid protease located
in the endoplasmic reticulum. This enzyme is essential for parasite
viability and is an attractive candidate for drug development.
Ilaria Russo et al.
doi:10.1038/nature08726
Abstract:
http://www.nature.com/nature/journal/v463/n7281/abs/nature08726.html
Article:
http://www.nature.com/nature/journal/v463/n7281/full/nature08726.html
----------------------
LETTERS
----------------------
A ground-based near-infrared emission spectrum of the exoplanet HD
189733b pp637-639
Infrared spectroscopy can probe the conditions and compositions of exoplanet
atmospheres. Previous results relied on space-based telescopes that do not
provide spectroscopic capability in the 2.4-5.2 [mu]m spectral region. Here,
ground-based observations of the dayside emission spectrum for HD 189733b
are reported between 2.0-2.4 [mu]m and 3.1-4.1 [mu]m; an unexpected feature
at around 3.25 [mu]m is found that is difficult to explain with models that
assume local thermodynamic equilibrium conditions, and is assigned to
methane.
Mark R. Swain et al.
doi:10.1038/nature08775
Abstract:
http://www.nature.com/nature/journal/v463/n7281/abs/nature08775.html
Article:
http://www.nature.com/nature/journal/v463/n7281/full/nature08775.html
Directional water collection on wetted spider silk pp640-643
Many plants and animals make use of biological surfaces with structural
features at the micro- and nanometre-scale that control the interaction with
water. The appearance of dew drops on spider webs is an illustration of how
they are one such material capable of efficiently collecting water from air.
The water-collecting ability of the capture silk of the Uloborus
walckenaerius spider is now shown to be the result of a unique fibre
structure that forms after wetting.
Yongmei Zheng et al.
doi:10.1038/nature08729
Abstract:
http://www.nature.com/nature/journal/v463/n7281/abs/nature08729.html
Article:
http://www.nature.com/nature/journal/v463/n7281/full/nature08729.html
Coherently wired light-harvesting in photosynthetic marine algae at ambient
temperature pp644-647
Elisabetta Collini et al.
doi:10.1038/nature08811
Abstract:
http://www.nature.com/nature/journal/v463/n7281/abs/nature08811.html
Article:
http://www.nature.com/nature/journal/v463/n7281/full/nature08811.html
Migrating tremors illuminate complex deformation beneath the seismogenic San
Andreas fault pp648-652
Despite extensive study of the San Andreas fault, its physical character and
deformation mode beneath the relatively shallow earthquake-generating
portion remain largely unconstrained. Here, continuous seismic data from
mid-2001 to 2008 is examined, using an approach that allows differentiation
between activities from nearby patches of the deep fault and begins to
unveil rich and complex patterns of tremor occurrence, in particular,
constant motion of the tremor source.
David R. Shelly
doi:10.1038/nature08755
Abstract:
http://www.nature.com/nature/journal/v463/n7281/abs/nature08755.html
Article:
http://www.nature.com/nature/journal/v463/n7281/full/nature08755.html
Mammalian biodiversity on Madagascar controlled by ocean
currents pp653-656
Madagascar has a striking and peculiar fauna. It has been proposed that the
ancestors of Madagascar's present-day mammal stock rafted there from Africa,
but the validity of this hypothesis is questioned. Using palaeogeographic
reconstructions and palaeo-oceanographic modelling, surface currents during
the Palaeogene period are now shown to have been capable of transporting the
animals to the island, as required by the hypothesis.
Jason R. Ali and Matthew Huber
doi:10.1038/nature08706
Abstract:
http://www.nature.com/nature/journal/v463/n7281/abs/nature08706.html
Article:
http://www.nature.com/nature/journal/v463/n7281/full/nature08706.html
Evidence for grid cells in a human memory network pp657-661
Rodents have an orientation map of their surroundings, produced and updated
by a network of neurons in the entorhinal cortex known as 'grid cells'.
However, it is currently unknown whether humans encode their location in a
similar manner. Using functional magnetic resonance imaging in humans, a
macroscopic signal representing a subject's position in a virtual reality
environment is now detected that meets the criteria for defining grid-cell
encoding.
Christian F. Doeller, Caswell Barry and Neil Burgess
doi:10.1038/nature08704
Abstract:
http://www.nature.com/nature/journal/v463/n7281/abs/nature08704.html
Article:
http://www.nature.com/nature/journal/v463/n7281/full/nature08704.html
Hsp90 prevents phenotypic variation by suppressing the mutagenic activity of
transposons pp662-665
Phenotypic robustness in the face of genetic and environmental perturbations
-- known as canalization -- relies on buffering mechanisms. Hsp90 chaperone
machinery has been proposed to be an evolutionarily conserved buffering
mechanism of phenotypic variance. Here, an additional, perhaps alternative,
mechanism whereby Hsp90 influences phenotypic variation is proposed; Hsp90
mutations can generate new variation by transposon-mediated mutagenesis.
Valeria Specchia et al.
doi:10.1038/nature08739
Abstract:
http://www.nature.com/nature/journal/v463/n7281/abs/nature08739.html
Article:
http://www.nature.com/nature/journal/v463/n7281/full/nature08739.html
Large, rare chromosomal deletions associated with severe early-onset
obesity pp666-670
The contribution of copy number variation to obesity -- a highly heritable
and genetically heterogeneous disorder -- is investigated in 300 Caucasian
patients to reveal that large, rare deletions are significantly enriched in
patients compared to controls. Several rare copy number variants are
identified that are recurrent in patients but absent or at much lower
prevalence in controls.
Elena G. Bochukova et al.
doi:10.1038/nature08689
Abstract:
http://www.nature.com/nature/journal/v463/n7281/abs/nature08689.html
Article:
http://www.nature.com/nature/journal/v463/n7281/full/nature08689.html
A new highly penetrant form of obesity due to deletions on chromosome 16p11.
2 pp671-675
Recently, numerous single nucleotide polymorphisms have been identified as
being associated with obesity, but these loci together account for only a
small fraction of the known heritable component. Here, an association is
reported between rare deletions of at least 593 kilobases at 16p11.2 and a
highly penetrant form of obesity. The strategy used of combining study of
extreme phenotypes with targeted follow-up is promising for identifying
missing heritability in obesity.
R. G. Walters et al.
doi:10.1038/nature08727
Abstract:
http://www.nature.com/nature/journal/v463/n7281/abs/nature08727.html
Article:
http://www.nature.com/nature/journal/v463/n7281/full/nature08727.html
TGF-[bgr]-FOXO signalling maintains leukaemia-initiating cells in chronic
myeloid leukaemia pp676-680
Chronic myeloid leukaemia is caused by a BCR-ABL fusion, a constitutively
active tyrosine kinase that, it is believed, leads to suppression of the
forkhead O transcription factors (FOXO). Although the use of the tyrosine
kinase inhibitor imatinib is a breakthrough for CML therapy, imatinib does
not deplete the leukaemia-initiating cells (LICs) that drive the recurrence
of CML. Foxo3a is now shown to have an essential role in the maintenance of
CML LICs in a mouse model.
Kazuhito Naka et al.
doi:10.1038/nature08734
Abstract:
http://www.nature.com/nature/journal/v463/n7281/abs/nature08734.html
Article:
http://www.nature.com/nature/journal/v463/n7281/full/nature08734.html
Multiple native states reveal persistent ruggedness of an RNA folding
landscape pp681-684
The 'thermodynamic hypothesis' proposes that the sequence of a biological
macromolecule defines its folded, active structure as a global energy
minimum in the folding landscape; however, it is not clear whether there is
only one global minimum or several local minima corresponding to active
conformations. Here, using single-molecule experiments, an RNA enzyme is
shown to fold into multiple distinct native states that interconvert.
Sergey V. Solomatin, Max Greenfeld, Steven Chu and Daniel Herschlag
doi:10.1038/nature08717
Abstract:
http://www.nature.com/nature/journal/v463/n7281/abs/nature08717.html
Article:
http://www.nature.com/nature/journal/v463/n7281/full/nature08717.html
Experimental evidence for a frustrated energy landscape in a
three-helix-bundle protein family pp685-688
The primary sequence of a protein defines its free-energy landscape and thus
determines the rate constants of folding and unfolding, with theory
suggesting that roughness in the energy landscape leads to slower folding.
However, obtaining experimental descriptions of this landscape is
challenging. Landscape roughness is now shown to be responsible for the
slower folding and unfolding times observed in the R16 and R17 domains of
[alpha]-spectrin relative to the similar R15 domain.
Beth G. Wensley et al.
doi:10.1038/nature08743
Abstract:
http://www.nature.com/nature/journal/v463/n7281/abs/nature08743.html
Article:
http://www.nature.com/nature/journal/v463/n7281/full/nature08743.html
Structure of the amantadine binding site of influenza M2 proton channels in
lipid bilayers pp689-692
The antiviral drugs amantadine and rimantadine target the M2 protein of
influenza A virus, making an understanding of its structure important for
the study of drug resistance. The results of a recent crystal structure of
M2 differ from those of a solution NMR structure with regards to binding of
these drugs, indicating a different mechanism of inhibition in each case.
Here, using solid-state NMR spectroscopy, two different amantadine-binding
sites are shown to exist in the phospholipid bilayers of M2.
Sarah D. Cady et al.
doi:10.1038/nature08722
Abstract:
http://www.nature.com/nature/journal/v463/n7281/abs/nature08722.html
Article:
http://www.nature.com/nature/journal/v463/n7281/full/nature08722.html
Directional water collection on wetted spider silk
在有雾的早晨，蜘蛛网会闪闪发光，这表明它们能以很高效率从潮湿空气中收集水滴。
对草间蜘蛛（Uloborus walckenaerius）的网所做的一项研究显示，这种能力取决于蜘
蛛网湿了之后所发生的一个结构变化。“湿后重构”的纤维以周期性纺锤节为特征，后
者由随机的纳米纤维构成，被排列整齐的纳米纤维结点分隔开。这种结构在纺锤节和结
点之间产生一个表面能量梯度，并在作用在与纺锤节或结点相接触的水滴上的压力上产
生一个差别。这样可以确保水能在结点周围不断凝结，然后被输送到纺锤节上，在那里
它能积聚成悬挂起来的大水滴，如本期封面所示。模仿变湿的蛛丝结构的一种人造丝也
能从薄雾中收集水滴。这项研究对于设计能从雾气中收集淡水或在工业过程中过滤液体
气溶胶的功能性表面的工作可能会有启发。（Letter p. 640）
支配细胞命运的机制（Cell fate in the balance）
Opposing microRNA families regulate self-renewal in mouse embryonic stem
cells
胚胎干细胞的分化既需要对自我更新进行抑制，又需要对一个特定的分化通道进行激
发。被称为微RNA（miRNA）的小型非编码RNA作为支配细胞命运的重要物质正在被人们
所认识。现在研究发现，一种名为“let-7”的著名miRNA负责抑制胚胎干细胞中的自我
更新程序。这种抑制可以被一组“胚胎干细胞调控型miRNA”（称之为ESCC miRNA，它
们调控细胞周期）逆转，说明“let-7”和ESCC miRNA之间的互动提供一个能够支配细
胞命运的机制。（Article p. 621; News & Views）
蛋白酶抗疟疾目标（Protease antimalarial target）
An aspartyl protease directs malaria effector proteins to the host cell /
Plasmepsin V licenses Plasmodium proteins for export into the host
erythrocyte
疟原虫生命周期的一个关键部分（也是使通过蚊子向其他宿主传播疟疾成为可能的一个
部分）涉及在宿主血红细胞内的一个生长阶段。在这个阶段，疟原虫细胞将几百种蛋白
输出到宿主血细胞中，它们会将宿主血细胞改造成一个适合疟原虫繁殖的环境。注定要
被输出的蛋白包含一个保守主题，即PEXEL，而当这个主题在内质网中被分解之后，蛋
白便能转位到宿主细胞中。现在，两项独立的研究工作显示，分解PEXEL主题的酶为门
冬氨酰蛋白酶“plasmepsin V”。这一发现的直接意义是，它表明“plasmepsin V”是
抗疟疾药物的一个潜在作用目标。（Articles pp. 627, 632）
太阳系外行星大气层的地基观测研究（Exoplanet atmospheres）
A ground-based near-infrared emission spectrum of the exoplanet HD?189733b
空间红外光谱仪器已在被称为“热木星”的太阳系外行星的大气中成功识别出了H2O、
CH4、CO2 和 CO等各种不同分子。现在Swain等人报告了在太空望远镜无法观测的近红
外波长对“热木星”HD 189733b的光面发射光谱所做的基于地面的观测研究。他们在约
3.25μm处发现了一个明亮的发射特征，该特征利用假设局部热动态平衡条件的当前模
型是不能预测到和难以解释的。来自甲烷的荧光发射（与在太阳系行星大气中所看到的
相似）似乎是一个可能的解释。这项工作表明太阳系外行星上的大气化学要比以前所想
的更复杂，同时它也将太阳系外行星分子光谱学研究领域向地基望远镜敞开了大门。
（Letter p. 637; News & Views）
光合作用中的量子效应（Wired for light）
Coherently wired light-harvesting in photosynthetic marine algae at ambient
temperature
光合作用中最令人着迷、被研究最多的特征之一是能量在光合作用复合物中进行传输的
极高效率。一项新的光谱研究，通过直接显示室温下在来自Chroomonas CCMP270海藻的
5-纳米宽的光合作用蛋白上电子激发的量子相干共享，证实了人们早先提出的量子效应
可能在其中发挥作用的暗示。观察表明，这些蛋白内相距较远的单元被量子相干连接在
一起，以增强集光效率。（Letter p. 644; News & Views）
圣安德烈斯断层地震发生带下的形变过程（San Andreas tremors）
Migrating tremors illuminate complex deformation beneath the seismogenic San
Andreas fault
尽管人们已经进行了广泛研究，但关于圣安德烈斯断层地震发生带下的形变过程仍然有
很多东西有待发现。现在，美国地质调查局的David Shelly报告了对从2001年年中到
2008年观察到的地震情况所做的一项分析，他采用的方法所能达到的时空分辨率高于以
前在该地区所能达到的程度。其分析显示，圣安德烈斯断层在帕克菲尔德附近是地壳底
部一个连续结构，同时它也揭示了在地震发生带下的那部分断层上的人们以前不知道
的、复杂的形变模式，其中包括以高达每小时80公里速度迁移的震动序列。（Letter
p. 648）
马达加斯加的哺乳动物最初乘木筏而来（Madagascar ahoy）
Mammalian biodiversity on Madagascar controlled by ocean currents
马达加斯加有一个非常引人瞩目而又非常奇特的动物区系。虽然马达加斯加的哺乳动物
与非洲哺乳动物有远亲关系，但它们显然已经孤立进化了数千万年。它们的祖先是怎样
到该岛上的？1940年，杰出的古生物学家George Gaylord Simpson提出，哺乳动物是乘
坐木筏随波逐流从非洲到达那里的，这就是所谓的“Sweepstakes”假说。这个假说可
解释本地动物区系的古怪特点——只不过洋流是向相反方向流的，即是朝着非洲方向
的，而不是远离非洲方向的。但认为马达加斯加和非洲大陆陆地直接相连的另一种解释
也被排除了，因为马达加斯加在哺乳动物开始它们演化旅程时是一个岛屿。Jason Ali
和 Matthew Huber提出了解决这一问题的一个办法：对始新世（距今超过5000万年前）
时的洋流所做的一项重建工作表明，在一段短暂的时期内，洋流的确是从西向东流的，
从而使得动物能够通过木筏到马达加斯加定居。（Letter p. 653; News & Views）
人类与老鼠的共同之处（On the grid for the rat race）
Evidence for grid cells in a human memory network
Edvard Moser及其同事发现，大鼠和小鼠拥有关于它们周围环境的一个方向图，是由被
称为“网格细胞”的大脑皮层神经元产生和更新的。该发现是近年来最为激动人心的神
经科学发现之一。这些细胞为自我定位提供了一个周期性非常强的表述。这便自然引出
一个问题：人类是否也有一个类似机制？Christian Doeller、Caswell Barry 和 Neil
Burgess的一篇论文为这个问题提供了答案。在这项研究中，他们将自由运动大鼠网格
细胞的单元记录与在虚拟环境中穿行的人的全脑磁共振成像（fMRI）结合在了一起。
Doeller等人能够检测到代表一个人在虚拟现实环境中位置的宏观fMRI信号，该信号符
合定义网格细胞编码的标准。所以，人类似乎是用一种与啮齿类动物非常像的方式来表
示位置和支持空间认知的。（Letter p. 657）
导致肥胖症的基因突变（Genetic link to obesity）
Large, rare chromosomal deletions associated with severe early-onset obesity
/ A new highly penetrant form of obesity due to deletions on chromosome
16p11.2
肥胖症是一种具有高度遗传性的疾病，但迄今所报告的遗传关联性只能解释身体质量指
数遗传变化的很小一部分。两个小组报告了染色体16p11.2上所发生的基因删除，它们
也许可解释所谓“高外显率”突变中部分“缺失的遗传性”。这类突变很罕见，但一旦
存在，就会以非常高的频率被与严重肥胖症联系起来。这跟与临床症候联系不是很密切
的更为常见的基因缺陷形成对比。Bochukova等人在300个患有严重早发性肥胖周的患者
身上发现了罕见的复发性版本数突变体，它们是由涉及包括SH2B1（已知参与“莱普
亭”和胰岛素的信号作用）在内的几种基因的删除造成的。这些患者很多还患有神经发
育症。Walters等人在31个患有一种以前未被识别出的极端肥胖症的患者的染色体
16p11.2上识别出至少593个千碱基对的删除。他们用来识别病灶的策略（利用数量较少
的、表现型较好的极端表现型人群进行研究，继之以定向全基因组关联研究和
“population cohort”研究）有望作为一种手段，来识别更具普遍性的复杂代谢疾病
中“缺失的遗传性”。（Letters pp. 666, 671）
流感病毒蛋白的两面性（Double life of flu virus protein）
Structure of the amantadine binding site of influenza M2 proton channels in
lipid bilayers
当前的H1N1流感病毒对成熟的抗病毒药物金刚胺和金刚乙胺有抵抗力。这两种药物以M2
蛋白为作用目标，该蛋白是一种多功能跨膜质子通道。这个通道的结构一直是一个有些
争议的话题，因为M2通道一部分的X-射线晶体结构所显示的电子密度相应于微孔N-端那
一部分的单一金刚胺分子，而该通道更大一部分的溶液NMR结构则显示有四个金刚乙胺
分子结合到螺旋体C-端朝向类脂的表面上。现在，随着处在一个磷脂双层中的M2通道的
高分辨率结构（该结构利用固态NMR光谱获得）的发表，这个问题似乎已经解决。该结
构显示金刚胺有两个结合点：N-端通道腔中一个高亲和度点和C-端蛋白表面上一个低亲
和度点。这项工作对于新兴抗流感药物的开发可能会有价值（这是一个重要目标，因为
2009年的季节性流感病毒对金刚胺是敏感的，但对“达菲”（Tamiflu）却有抵抗
力），这便提出一个可能性：将来可能会出现多种抗药性病毒类型。（Letter p.
689）
----------------------
NEWS AND VIEWS
----------------------
Biogeography: Washed up in Madagascar pp613-614
How, when and from where did Madagascar's unique mammalian fauna originate?
The idea that the ancestors of that fauna rafted from Africa finds support
in innovative simulations of ancient ocean currents.
David W. Krause
doi:10.1038/463613a
http://www.nature.com/nature/journal/v463/n7281/full/463613a.html
Photosynthesis: Quantum design for a light trap pp614-615
The photosynthetic apparatus of cryptophyte algae is odd - its pigments are
farther apart than is expected for efficient functioning. A study into how
this apparatus works so well finds quantum effects at play.
Rienk van Grondelle and Vladimir I. Novoderezhkin
doi:10.1038/463614a
http://www.nature.com/nature/journal/v463/n7281/full/463614a.html
Stem cells: Big roles for small RNAs p616
Embryonic stem cells can create copies of themselves, but can also mature
into almost any type of cell in the body. Tiny gene regulators called
microRNAs are now shown to have a role in directing these properties.
Frank J. Slack
doi:10.1038/463616a
http://www.nature.com/nature/journal/v463/n7281/full/463616a.html
50 & 100 years ago p617
doi:10.1038/463617b
http://www.nature.com/nature/journal/v463/n7281/full/463617b.html
Extrasolar planets: Fluorescent methane spotted pp617-618
The atmospheric properties of distant worlds are becoming increasingly
clear. The latest observations reveal fluorescent emission from methane in
the upper atmosphere of a Jupiter-like extrasolar planet.
Seth Redfield
doi:10.1038/463617a
http://www.nature.com/nature/journal/v463/n7281/full/463617a.html
Biomaterials: Dew catchers p618
Magdalena Helmer
doi:10.1038/463618a
http://www.nature.com/nature/journal/v463/n7281/full/463618a.html
Applied physics: Nanothermal trumpets p619
The thermal process known as Joule heating, which often plagues electronic
devices, has been turned to good use: making devices that can produce sound
as well as reproduce music and speech.
Rama Venkatasubramanian
doi:10.1038/463619a
http://www.nature.com/nature/journal/v463/n7281/full/463619a.html
----------------------
ARTICLES
----------------------
Opposing microRNA families regulate self-renewal in mouse embryonic stem
cells pp621-626
The differentiation of an embryonic stem cell (ESC) requires both
suppression of the self-renewal process and activation of the specific
differentiation pathway. The let-7 family of microRNAs (miRNAs) are now
shown to suppress the self-renewal program in cells that are normally unable
to silence this program, whereas introduction of ESC cell cycle regulating
miRNAs blocks the action of let-7. Thus, the interplay between these two
groups of miRNAs dictates cell fate.
Collin Melton, Robert L. Judson and Robert Blelloch
doi:10.1038/nature08725
Abstract:
http://www.nature.com/nature/journal/v463/n7281/abs/nature08725.html
Article:
http://www.nature.com/nature/journal/v463/n7281/full/nature08725.html
An aspartyl protease directs malaria effector proteins to the host
cell pp627-631
To survive and evade host responses, malaria parasites export several
hundred proteins into the host cell on infection. A feature of these
proteins is a conserved, pentameric motif that is cleaved by an unknown
protease before export. This is one of two independent studies revealing the
identity of the protease as plasmepsin V, an aspartic acid protease located
in the endoplasmic reticulum. This enzyme is essential for parasite
viability and is an attractive candidate for drug development.
Justin A. Boddey et al.
doi:10.1038/nature08728
Abstract:
http://www.nature.com/nature/journal/v463/n7281/abs/nature08728.html
Article:
http://www.nature.com/nature/journal/v463/n7281/full/nature08728.html
Plasmepsin V licenses Plasmodium proteins for export into the host
erythrocyte pp632-636
To survive and evade host responses, malaria parasites export several
hundred proteins into the host cell on infection. A feature of these
proteins is a conserved, pentameric motif that is cleaved by an unknown
protease before export. This is one of two independent studies revealing the
identity of the protease as plasmepsin V, an aspartic acid protease located
in the endoplasmic reticulum. This enzyme is essential for parasite
viability and is an attractive candidate for drug development.
Ilaria Russo et al.
doi:10.1038/nature08726
Abstract:
http://www.nature.com/nature/journal/v463/n7281/abs/nature08726.html
Article:
http://www.nature.com/nature/journal/v463/n7281/full/nature08726.html
----------------------
LETTERS
----------------------
A ground-based near-infrared emission spectrum of the exoplanet HD
189733b pp637-639
Infrared spectroscopy can probe the conditions and compositions of exoplanet
atmospheres. Previous results relied on space-based telescopes that do not
provide spectroscopic capability in the 2.4-5.2 [mu]m spectral region. Here,
ground-based observations of the dayside emission spectrum for HD 189733b
are reported between 2.0-2.4 [mu]m and 3.1-4.1 [mu]m; an unexpected feature
at around 3.25 [mu]m is found that is difficult to explain with models that
assume local thermodynamic equilibrium conditions, and is assigned to
methane.
Mark R. Swain et al.
doi:10.1038/nature08775
Abstract:
http://www.nature.com/nature/journal/v463/n7281/abs/nature08775.html
Article:
http://www.nature.com/nature/journal/v463/n7281/full/nature08775.html
Directional water collection on wetted spider silk pp640-643
Many plants and animals make use of biological surfaces with structural
features at the micro- and nanometre-scale that control the interaction with
water. The appearance of dew drops on spider webs is an illustration of how
they are one such material capable of efficiently collecting water from air.
The water-collecting ability of the capture silk of the Uloborus
walckenaerius spider is now shown to be the result of a unique fibre
structure that forms after wetting.
Yongmei Zheng et al.
doi:10.1038/nature08729
Abstract:
http://www.nature.com/nature/journal/v463/n7281/abs/nature08729.html
Article:
http://www.nature.com/nature/journal/v463/n7281/full/nature08729.html
Coherently wired light-harvesting in photosynthetic marine algae at ambient
temperature pp644-647
Elisabetta Collini et al.
doi:10.1038/nature08811
Abstract:
http://www.nature.com/nature/journal/v463/n7281/abs/nature08811.html
Article:
http://www.nature.com/nature/journal/v463/n7281/full/nature08811.html
Migrating tremors illuminate complex deformation beneath the seismogenic San
Andreas fault pp648-652
Despite extensive study of the San Andreas fault, its physical character and
deformation mode beneath the relatively shallow earthquake-generating
portion remain largely unconstrained. Here, continuous seismic data from
mid-2001 to 2008 is examined, using an approach that allows differentiation
between activities from nearby patches of the deep fault and begins to
unveil rich and complex patterns of tremor occurrence, in particular,
constant motion of the tremor source.
David R. Shelly
doi:10.1038/nature08755
Abstract:
http://www.nature.com/nature/journal/v463/n7281/abs/nature08755.html
Article:
http://www.nature.com/nature/journal/v463/n7281/full/nature08755.html
Mammalian biodiversity on Madagascar controlled by ocean
currents pp653-656
Madagascar has a striking and peculiar fauna. It has been proposed that the
ancestors of Madagascar's present-day mammal stock rafted there from Africa,
but the validity of this hypothesis is questioned. Using palaeogeographic
reconstructions and palaeo-oceanographic modelling, surface currents during
the Palaeogene period are now shown to have been capable of transporting the
animals to the island, as required by the hypothesis.
Jason R. Ali and Matthew Huber
doi:10.1038/nature08706
Abstract:
http://www.nature.com/nature/journal/v463/n7281/abs/nature08706.html
Article:
http://www.nature.com/nature/journal/v463/n7281/full/nature08706.html
Evidence for grid cells in a human memory network pp657-661
Rodents have an orientation map of their surroundings, produced and updated
by a network of neurons in the entorhinal cortex known as 'grid cells'.
However, it is currently unknown whether humans encode their location in a
similar manner. Using functional magnetic resonance imaging in humans, a
macroscopic signal representing a subject's position in a virtual reality
environment is now detected that meets the criteria for defining grid-cell
encoding.
Christian F. Doeller, Caswell Barry and Neil Burgess
doi:10.1038/nature08704
Abstract:
http://www.nature.com/nature/journal/v463/n7281/abs/nature08704.html
Article:
http://www.nature.com/nature/journal/v463/n7281/full/nature08704.html
Hsp90 prevents phenotypic variation by suppressing the mutagenic activity of
transposons pp662-665
Phenotypic robustness in the face of genetic and environmental perturbations
-- known as canalization -- relies on buffering mechanisms. Hsp90 chaperone
machinery has been proposed to be an evolutionarily conserved buffering
mechanism of phenotypic variance. Here, an additional, perhaps alternative,
mechanism whereby Hsp90 influences phenotypic variation is proposed; Hsp90
mutations can generate new variation by transposon-mediated mutagenesis.
Valeria Specchia et al.
doi:10.1038/nature08739
Abstract:
http://www.nature.com/nature/journal/v463/n7281/abs/nature08739.html
Article:
http://www.nature.com/nature/journal/v463/n7281/full/nature08739.html
Large, rare chromosomal deletions associated with severe early-onset
obesity pp666-670
The contribution of copy number variation to obesity -- a highly heritable
and genetically heterogeneous disorder -- is investigated in 300 Caucasian
patients to reveal that large, rare deletions are significantly enriched in
patients compared to controls. Several rare copy number variants are
identified that are recurrent in patients but absent or at much lower
prevalence in controls.
Elena G. Bochukova et al.
doi:10.1038/nature08689
Abstract:
http://www.nature.com/nature/journal/v463/n7281/abs/nature08689.html
Article:
http://www.nature.com/nature/journal/v463/n7281/full/nature08689.html
A new highly penetrant form of obesity due to deletions on chromosome 16p11.
2 pp671-675
Recently, numerous single nucleotide polymorphisms have been identified as
being associated with obesity, but these loci together account for only a
small fraction of the known heritable component. Here, an association is
reported between rare deletions of at least 593 kilobases at 16p11.2 and a
highly penetrant form of obesity. The strategy used of combining study of
extreme phenotypes with targeted follow-up is promising for identifying
missing heritability in obesity.
R. G. Walters et al.
doi:10.1038/nature08727
Abstract:
http://www.nature.com/nature/journal/v463/n7281/abs/nature08727.html
Article:
http://www.nature.com/nature/journal/v463/n7281/full/nature08727.html
TGF-[bgr]-FOXO signalling maintains leukaemia-initiating cells in chronic
myeloid leukaemia pp676-680
Chronic myeloid leukaemia is caused by a BCR-ABL fusion, a constitutively
active tyrosine kinase that, it is believed, leads to suppression of the
forkhead O transcription factors (FOXO). Although the use of the tyrosine
kinase inhibitor imatinib is a breakthrough for CML therapy, imatinib does
not deplete the leukaemia-initiating cells (LICs) that drive the recurrence
of CML. Foxo3a is now shown to have an essential role in the maintenance of
CML LICs in a mouse model.
Kazuhito Naka et al.
doi:10.1038/nature08734
Abstract:
http://www.nature.com/nature/journal/v463/n7281/abs/nature08734.html
Article:
http://www.nature.com/nature/journal/v463/n7281/full/nature08734.html
Multiple native states reveal persistent ruggedness of an RNA folding
landscape pp681-684
The 'thermodynamic hypothesis' proposes that the sequence of a biological
macromolecule defines its folded, active structure as a global energy
minimum in the folding landscape; however, it is not clear whether there is
only one global minimum or several local minima corresponding to active
conformations. Here, using single-molecule experiments, an RNA enzyme is
shown to fold into multiple distinct native states that interconvert.
Sergey V. Solomatin, Max Greenfeld, Steven Chu and Daniel Herschlag
doi:10.1038/nature08717
Abstract:
http://www.nature.com/nature/journal/v463/n7281/abs/nature08717.html
Article:
http://www.nature.com/nature/journal/v463/n7281/full/nature08717.html
Experimental evidence for a frustrated energy landscape in a
three-helix-bundle protein family pp685-688
The primary sequence of a protein defines its free-energy landscape and thus
determines the rate constants of folding and unfolding, with theory
suggesting that roughness in the energy landscape leads to slower folding.
However, obtaining experimental descriptions of this landscape is
challenging. Landscape roughness is now shown to be responsible for the
slower folding and unfolding times observed in the R16 and R17 domains of
[alpha]-spectrin relative to the similar R15 domain.
Beth G. Wensley et al.
doi:10.1038/nature08743
Abstract:
http://www.nature.com/nature/journal/v463/n7281/abs/nature08743.html
Article:
http://www.nature.com/nature/journal/v463/n7281/full/nature08743.html
Structure of the amantadine binding site of influenza M2 proton channels in
lipid bilayers pp689-692
The antiviral drugs amantadine and rimantadine target the M2 protein of
influenza A virus, making an understanding of its structure important for
the study of drug resistance. The results of a recent crystal structure of
M2 differ from those of a solution NMR structure with regards to binding of
these drugs, indicating a different mechanism of inhibition in each case.
Here, using solid-state NMR spectroscopy, two different amantadine-binding
sites are shown to exist in the phospholipid bilayers of M2.
Sarah D. Cady et al.
doi:10.1038/nature08722
Abstract:
http://www.nature.com/nature/journal/v463/n7281/abs/nature08722.html
Article:
http://www.nature.com/nature/journal/v463/n7281/full/nature08722.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）
