当前位置：首页 >> 专题栏目 >> 中文摘要
2007年8月30日Nature中文摘要
 BIOX.CN  来源：生命经纬    2007年08月30日
封面故事： 兰花的起源
Dating the origin of the Orchidaceae from a fossil orchid with its
pollinator
自从达尔文时代以来，生物学家一直为兰花和它们的授粉者之间的亲密关系着
迷。这种关系之久远，从本期封面所示化石就可见一斑。化石中是一只无刺的工
蜂，带着兰花的一个花粉块，保存在距今1500万至2000万年前的琥珀中，是在多
米尼加共和国发现的。这个花粉块是雄性生殖结构，在授粉期间作为一个结构单
位被转移，带有一团花粉颗粒。该发现让人吃惊之处是，它是第一个明确来自兰
科的化石。花粉块的形态说明该兰花属于斑叶兰（Goodyerinae）。通过将这一
信息与来自其他相关化石植物的年代数据结合起来，研究人员便获得了对兰科植
物分子系统发生学的一个新的校正结果。分析结果否定了兰花起源于较近年代
（第三纪）的假设；相反，它表明它们起源于距今8000万年前的晚白垩纪。
（Letter p. 1042; www.nature.com/podcast）


哺乳动物性别特异性行为的形成时间（Love is in the air）
A functional circuit underlying male sexual behaviour in the female
mouse brain
哺乳动物中雄性与雌性行为之间的巨大差别是怎样形成的？ 关于这个问题的主
导理论是，性腺激素在脑发育早期诱导神经回路，让它们去诱导或抑制雄性或雌
性特征。但新的研究工作表明，雄性或雌性的交配偏好并不是在发育过程中确定
的。信息素感知已被发现能够改变成年雌性实验鼠的性行为。这一现象的关键是
“犁鼻器”（vomeronasal organ），一种功能未知的辅助嗅觉器官，存在于鼻
与嘴之间的犁骨（vomer bone）中。“犁鼻器”有缺陷的雌性会表现出雄性性行
为，说明雄性和雌性行为的促动回路都存在于每个性别的脑中，是通过性别特异
性的传感调控机制打开或关闭的。人类是在胎儿发育过程中失去“犁鼻器”的，
但这一发现为研究人类的性别特异性行为开辟了新途径。（Article p. 1009;
News & Views）


人类胚胎干细胞能够在体外自然产生hdFs（How stem cells carve a niche）
IGF and FGF cooperatively establish the regulatory stem cell niche of
pluripotent human cells in vitro
关于干细胞利基（stem cell niche）的概念因本期Nature上报告的一个重要发
现将会进一步发展。干细胞种群是在特定的解剖位置或称利基的地方形成的，这
些利基调控它们参与组织更新和修复的方式。现在，研究发现，人类胚胎干细胞
能够在体外自然产生“源自人类胚胎干细胞的成纤维细胞一样的利基细胞”
（hdFs），尽管已经离开了它们的体内微环境。然后，这些hdFs为支持性蛋白
（其中包括胰岛素一样的生长因子-2，它能促进干细胞存活和自我更新）提供一
个连续来源。这为我们思考人类胚胎干细胞的生长与分异的控制问题开创了一个
新方法。如果人类胚胎干细胞能够被可靠地沿一个特定的通道来引导，那么从治
疗角度来讲它们将变得更有趣。（Article p. 1015）


原始行星的生长和小行星的形成（Think inside the envelope）
Rapid planetesimal formation in turbulent circumstellar disks
一个原始行星盘通过不断吸收其周围新生包裹层中的物质而生长的现象，已在
Class 0 protostar NGC 1333–IRAS 4B中被首次观测到了。这是恒星和行星体
系形成过程早期一个关键步骤，所有这样的系统都被认为要经过这个步骤。“斯
皮策太空望远镜”的观测结果显示了一条来自水蒸气的在中红外波段的丰富的发
射线， 这表明它起源于一个极为致密的盘表面，是被向内掉的（infalling）包
裹材料的激波加热的（Letter p. 1026）。一个原始行星盘一旦形成，随着尘埃
颗粒之间的碰撞形成更大的天体，小行星被认为就会形成。但当前的理论仅仅预
测能够形成直径一米左右的小行星，而认为这样的像顽石一样的小行星在向中心
的原始恒星掉的过程中速度太快，无法形成直径达到一公里的小行星。新的计算
机模拟表明，气体盘与这些顽石之间的相互作用能形成极为致密的区域；在这些
区域中，顽石彼此之间距离非常近，以至于它们之间的相互吸引力会将它们吸到
一起，形成大小达很多公里的固体天体，从而直接形成作为行星构造单元的小行
星。（Letter p. 1022; News & Views）


25亿年前地球大气中氧含量上升的原因（Waitng for oxygen）
Increased subaerial volcanism and the rise of atmospheric oxygen 2.5
billion years ago
对地球上的生命来说非常重要的大气中氧含量的上升发生在距今大约25亿年前。
但关于被认为对这一事件负责的能产生氧的藻青菌的证据，是在距今2亿年前的
岩石中发现的。如果这些细菌的确提供了氧，为什么有这么一个时间延迟？ Lee
Kump 和 Mark Barley认为地球的构造演化是关键。首先，海底火山可能曾经起
到氧的一个封存库的作用，使氧不能逃逸进大气中。然后，在大约25亿年前发生
的大陆稳定化这一主要构造事件之后，火山活动的模式发生了变化，当时海底火
山活动突然减小了，而还原性较差的地面火山变得更为普遍。所以，由于被海底
火山吸收的氧变少了，便为大气中氧含量的上升创造了条件。（Letter p.
1033; News & Views）


植物气孔对未来径流变化的影响（Watering the plants）
Projected increase in continental runoff due to plant responses to
increasing carbon dioxide
对植物生理效应对陆地水径流未来变化的贡献所做的一项评估表明，按照关于未
来全球变暖的情景设想，发生洪灾的风险可能要比人们所假设的更大。让二氧化
碳进入植物、让水分逃逸的气孔，当二氧化碳浓度高时开启程度要小一些，以减
少植物水分的损失，从而使更多的水留在地表。这一效应可能是20世纪所观测到
的陆地径流增加的原因之一，但关于未来径流变化的大多数预测都没有将它考虑
进去。“二氧化碳当量”的概念（该概念被普遍用来比较温室气体对气候的效
应）也没有考虑到这一效应，所以可能需要根据这些发现对其进行修改。
（Letter p. 1037）


关于流动性对生物多样性影响的理论研究（Species on the move）
Mobility promotes and jeopardizes biodiversity in rock–paper–
scissors games
流动性是多数生态系统中的一个重要因素，从那些由一个地方向另一个地方迁徙
的动物到到处游动的细菌都是这样。Reichenbach等人在一项可能是关于流动性
对生物多样性影响的第一个理论研究中，用“石头－剪刀—布”游戏对竞争的物
种进行了模拟。在静态的种群中，现状可以保持。但当流动性超过一个临界值
时，生物多样性就会丢失。低于这个临界值，亚种群可以共存，生物多样性可以
维持——这一结果可能会被证明有助于生物多样性保护策略的设计。（Letter
p. 1046）


小鼠有了一个“HapMap”（Now mice get a HapMap）
A sequence-based variation map of 8.27 million SNPs in inbred mouse
strains
用被用来研究毒性和人类疾病的很多小鼠模型进行研究工作的遗传学家，现在有
了一个重要的新工具。4个野生型品系和11个近交系实验室小鼠品系的基因组已
经完成重新测序，得到一个关于DNA变异的全面的数据库。研究人员识别出了大
约830万个单碱基对差别，被称为“核苷酸多态性”（SNPs）。这些数据作为小
鼠的一个“HapMap”公开发布在网上，网址为http://mouse.perlegen.com/。这
套SNP标记的密度和质量对于一种哺乳动物基因组来说是前所未有的，将为识别
小鼠表现型差异的遗传决定因子提供一个强大工具。（Letter p. 1050）


果蝇能品尝出汽水（Drosophila’s taste for soda）
The detection of carbonation by the Drosophila gustatory system
果蝇被水果味吸引并不奇怪。最近的研究工作显示，果蝇还能嗅到二氧化碳并做
出反应。二氧化碳是果蝇在野外可能会碰到的发酵中的水果的一种标记物。现
在，果蝇还被发现能够通过其吻部的一组专门的神经元“尝”到以碳酸水形式存
在的二氧化碳。这一新颖的味觉模式有可能帮助果蝇获得由微生物所产生的营养
物质。（Letter p. 1054）


Tip60抑制肿瘤的前提（Tip60 as an oncogene）
Tip60 is a haplo-insufficient tumour suppressor required for an
oncogene-induced DNA damage response
乙酰转移酶Tip60调控转录，涉及DNA的损伤响应。现在，它被发现在小鼠模型中
和在人类肿瘤中都具有体内肿瘤抑制活性。人类Tip60位点（HTATIP）在头部和
颈部鳞状细胞癌、乳腺癌和淋巴癌中都经常突变。在组织微阵列上着色的核
Tip60在各种不同肿瘤中都丢失了，而且最显著的是在乳腺癌中也丢失了。这项
工作表明，要在初发肿瘤细胞中发起一个由致癌基因诱导的DNA损伤响应，Tip60
的浓度必需达到临界水平：这一防卫机制的失效可能与p53突变发生协同作用，
共同促进肿瘤的发育。（Letter p. 1063）



----------------------
NEWS AND VIEWS
----------------------
Behavioural neurobiology: Females can also be from Mars pp999 - 1000
Is the preference to mate as a male or a female irreversibly set
during development? Apparently not: a study in mice shows that
pheromone perception determines how an adult female behaves sexually.
Nirao M. Shah and S. Marc Breedlove
doi:10.1038/nature05892
http://www.nature.com/nature/journal/v448/n7157/full/nature05892.html

Theoretical physics: A black hole full of answers pp1000 - 1001
A facet of string theory, the currently favoured route to a 'theory of
everything', might help to explain some properties of exotic matter
phases ― such as some peculiarities of high-temperature
superconductors.
Jan Zaanen
doi:10.1038/4481000a
http://www.nature.com/nature/journal/v448/n7157/full/4481000a.html

Molecular biology: Damage control pp1001 - 1002
The chemical composition of normal DNA at the end of chromosomes does
not differ from that of damaged and broken DNA within chromosomes. New
findings hint at how the DNA-repair machinery distinguishes the two.
Claus M. Azzalin and Joachim Lingner
doi:10.1038/4481001a
http://www.nature.com/nature/journal/v448/n7157/full/4481001a.html

Planets: The first movement p1003
How do large objects form from the dusty gas surrounding a young star?
A simulation suggests that several familiar processes, among them gas
turbulence and self-gravitation, might work together to get the job
done.
Jeff Cuzzi
doi:10.1038/4481003a
http://www.nature.com/nature/journal/v448/n7157/full/4481003a.html

Translation: Duality in the genetic code pp1004 - 1005
The encoding of two non-universal amino acids involves dynamic
redefinition of 'stop' signals in the genetic code. Bacteria with
multiple proteins containing these amino acids add to our appreciation
of coding versatility.
John F. Atkins and Pavel V. Baranov
doi:10.1038/4481004a
http://www.nature.com/nature/journal/v448/n7157/full/4481004a.html

Palaeoclimate: Oxygen's rise reduced pp1005 - 1006
Why did oxygen not appear in Earth's atmosphere until hundreds of
millions of years after photosynthesizing organisms first produced it?
Perhaps because reducing gases from undersea volcanoes claimed it
first.
Timothy W. Lyons
doi:10.1038/4481005a
http://www.nature.com/nature/journal/v448/n7157/full/4481005a.html

Materials science: Polymer crystals downsized pp1006 - 1007
A record has been broken ― the smallest-ever polymer crystals have
been prepared. Their surprising shape provides crucial evidence that
might help explain how polymers crystallize.
Stephen Z. D. Cheng
doi:10.1038/4481006a
http://www.nature.com/nature/journal/v448/n7157/full/4481006a.html

----------------------
ARTICLES
----------------------
A functional circuit underlying male sexual behaviour in the female
mouse brain pp1009 - 1014
Female mice with genetic or physical lesions of the vomeronasal organ
(VNO) display strikingly masculine sexual behavior, suggesting that
the masculine circuitry is actually intact even in females but is
normally suppressed by VNO function.
Tali Kimchi, Jennings Xu and Catherine Dulac
doi:10.1038/nature06089
Abstract:
http://www.nature.com/nature/journal/v448/n7157/abs/nature06089.html
Article:
http://www.nature.com/nature/journal/v448/n7157/full/nature06089.html

IGF and FGF cooperatively establish the regulatory stem cell niche of
pluripotent human cells in vitro pp1015 - 1021
Insulin-like growth factor II (IGF-II) has a direct role in the
survival and self-renewal of pluripotent human embryonic stem cells
(hESCs). Evidence is also provided that IGF-II is expressed by
supportive hESC-derived fibroblasts that are produced by the hESC
themselves, revealing that pluripotent hESCs produce their own
supportive stem cell niche that is capable of supplying critical
factors to maintain hESCs in culture.
Sean C. Bendall et al.
doi:10.1038/nature06027
Abstract:
http://www.nature.com/nature/journal/v448/n7157/abs/nature06027.html
Article:
http://www.nature.com/nature/journal/v448/n7157/full/nature06027.html

----------------------
LETTERS
----------------------
Rapid planetesimal formation in turbulent circumstellar disks pp1022
- 1025
Anders Johansen et al.
doi:10.1038/nature06086
Abstract:
http://www.nature.com/nature/journal/v448/n7157/abs/nature06086.html
Article:
http://www.nature.com/nature/journal/v448/n7157/full/nature06086.html

The development of a protoplanetary disk from its natal
envelope pp1026 - 1028
The youngest protostellar objects show many signs of rapid development
from their initial, spheroidal configurations. Watson et al. find in
NGC1333 ― IRAS4B a rich emission spectrum of H2O, at wavelengths
20-37 mm, which indicates an origin in extremely dense, warm gas. They
model the emission as infall from a protostellar envelope onto the
surface of a deeply embedded, dense disc. This is the only example in
a sample of 30 class 0 objects, perhaps arising from a favourable
orientation or this may be an early and short-lived stage in the
evolution of a protoplanetary disk.
Dan M. Watson et al.
doi:10.1038/nature06087
Abstract:
http://www.nature.com/nature/journal/v448/n7157/abs/nature06087.html
Article:
http://www.nature.com/nature/journal/v448/n7157/full/nature06087.html

Direct observation of second-order atom tunnelling pp1029 - 1032
Direct, time-resolved observations of the correlated tunnelling of two
interacting ultracold atoms through a barrier in a double-well
potential are reported. Second-order tunnelling events, which are
found to be the dominating dynamical effect in the strongly
interacting regime, have not been previously directly observed with
ultracold atoms.
S. Folling et al.
doi:10.1038/nature06112
Abstract:
http://www.nature.com/nature/journal/v448/n7157/abs/nature06112.html
Article:
http://www.nature.com/nature/journal/v448/n7157/full/nature06112.html

Increased subaerial volcanism and the rise of atmospheric oxygen
2.5[thinsp]billion years ago pp1033 - 1036
The rise of atmospheric oxygen about 2.5 billion years ago occurred
because the predominant sink for oxygen, enhanced submarine volcanism,
was abruptly diminished. Submarine volcanoes are more reducing than
subaerial volcanoes, so a shift from predominantly submarine to a mix
of subaerial and submarine volcanism following a major tectonic
episode of continental stabilization would have reduced the overall
sink for oxygen and led to the rise of atmospheric oxygen.
Lee R. Kump and Mark E. Barley
doi:10.1038/nature06058
Abstract:
http://www.nature.com/nature/journal/v448/n7157/abs/nature06058.html
Article:
http://www.nature.com/nature/journal/v448/n7157/full/nature06058.html

Projected increase in continental runoff due to plant responses to
increasing carbon dioxide pp1037 - 1041
An ensemble of experiments is used with a global climate model to
assess the contribution of plant 'physiological forcing' to future
changes in continental runoff. It is found that the effect increases
simulated global mean runoff by 6 per cent when the concentration of
carbon dioxide is doubled relative to pre-industrial levels; an
increase that is comparable to that simulated in response to climate
change caused by radiative forcing. This finding suggests that the
risk of flooding may be greater than previously assumed under future
global warming scenarios.
Richard A. Betts et al.
doi:10.1038/nature06045
Abstract:
http://www.nature.com/nature/journal/v448/n7157/abs/nature06045.html
Article:
http://www.nature.com/nature/journal/v448/n7157/full/nature06045.html

Dating the origin of the Orchidaceae from a fossil orchid with its
pollinator pp1042 - 1045
The antiquity of the close relationship between orchids and their
pollinators is demonstrated by a 15-20 million years old fossil of an
orchid pollinarium attached to the business end of a stingless bee,
preserved in amber from the Dominican Republic. This spectacular find
is used to constrain the evolution of orchids, suggesting that the
most recent common ancestor of orchids lived in the Late Cretaceous.
Santiago R. Ramirez et al.
doi:10.1038/nature06039
Abstract:
http://www.nature.com/nature/journal/v448/n7157/abs/nature06039.html
Article:
http://www.nature.com/nature/journal/v448/n7157/full/nature06039.html

Mobility promotes and jeopardizes biodiversity in rock-paper-scissors
games pp1046 - 1049
This paper theoretically investigates the influence of mobility on
biodiversity using a spatial 'rock-paper-scissors' game. A critical
threshold of motility is identified, above which biodiversity is lost,
but below which an entanglement of travelling spiral waves emerges and
biodiversity is maintained.
Tobias Reichenbach, Mauro Mobilia and Erwin Frey
doi:10.1038/nature06095
Abstract:
http://www.nature.com/nature/journal/v448/n7157/abs/nature06095.html
Article:
http://www.nature.com/nature/journal/v448/n7157/full/nature06095.html

A sequence-based variation map of 8.27 million SNPs in inbred mouse
strains pp1050 - 1053
The genomic resources for laboratory mice are greatly expanded by
resequencing the genomes of 15 different strains to find single
nucleotide polymorphisms. This creates a 'HapMap' for mice with 8.27
million markers.
Kelly A. Frazer et al.
doi:10.1038/nature06067
Abstract:
http://www.nature.com/nature/journal/v448/n7157/abs/nature06067.html
Article:
http://www.nature.com/nature/journal/v448/n7157/full/nature06067.html

The detection of carbonation by the Drosophila gustatory system pp1054
- 1057
The fruitfly is able to smell and respond to CO2, but this paper shows
that they can also taste CO2 in the form of carbonated water. A
population of neurons that detect carbonation are identified, and it
is suggested that they allow the fly to track down nutrients from
growing microorganisms.
Walter Fischler, Priscilla Kong, Sunanda Marella and Kristin Scott
doi:10.1038/nature06101
Abstract:
http://www.nature.com/nature/journal/v448/n7157/abs/nature06101.html
Article:
http://www.nature.com/nature/journal/v448/n7157/full/nature06101.html

Dominant-negative mutations in the DNA-binding domain of STAT3 cause
hyper-IgE syndrome pp1058 - 1062
Hyper-immunoglobulin E syndrome (HIES) is a complex primary
immunodeficiency associated with inflammation, high levels of serum
IgE, multiple infections and skeletal abnormalities. In this paper,
the disease is linked to germline, heterozygous in-frame mutations in
the DNA binding domain of the transcription activator STAT3 in eight
of fifteen unrelated patients.
Yoshiyuki Minegishi et al.
doi:10.1038/nature06096
Abstract:
http://www.nature.com/nature/journal/v448/n7157/abs/nature06096.html
Article:
http://www.nature.com/nature/journal/v448/n7157/full/nature06096.html

Tip60 is a haplo-insufficient tumour suppressor required for an
oncogene-induced DNA damage response pp1063 - 1067
The acetyl-transferase Tip60 regulates transcription and is involved
in the DNA damage response. Now, work from a mouse model and in-human
tumours provides evidence that Tip60 is a tumour suppressor gene, and
suggests that Tip60 functions in an oncogene-induced DNA damage
response that restrains early tumourigenesis.
Chiara Gorrini et al.
doi:10.1038/nature06055
Abstract:
http://www.nature.com/nature/journal/v448/n7157/abs/nature06055.html
Article:
http://www.nature.com/nature/journal/v448/n7157/full/nature06055.html

Protection of telomeres through independent control of ATM and ATR by
TRF2 and POT1 pp1068 - 1071
At a gross level, telomere ends resemble the ends of a double-strand
break caused by DNA damage, yet telomeres do not activate the DNA
damage response. An insight is offered as to how this response is
suppressed. Two telomere-binding proteins, TRF2 and POT1, inhibit the
activities of two upstream 'sensor' damage-responsive kinases, ATM and
ATR, respectively. As these kinases initiate the signalling cascades
that provoke the repair of damaged DNA, their inhibition by TRF2 and
POT1 makes the telomere ends 'invisible' to the DNA repair machinery.
Eros Lazzerini Denchi and Titia de Lange
doi:10.1038/nature06065
Abstract:
http://www.nature.com/nature/journal/v448/n7157/abs/nature06065.html
Article:
http://www.nature.com/nature/journal/v448/n7157/full/nature06065.html

Crystal structure of the MgtE Mg2+ transporter pp1072 - 1075
The crystal structure of a member of the MgtE family of Mg2+
transporters at 3.5A resolution, and the structure of just the
cytoplasmic domain in the presence and absence of Mg2+ is described.
An elegant gating mechanism involving negative feedback by Mg2+ is
also proposed.
Motoyuki Hattori et al.
doi:10.1038/nature06093
Abstract:
http://www.nature.com/nature/journal/v448/n7157/abs/nature06093.html
Article:
http://www.nature.com/nature/journal/v448/n7157/full/nature06093.html
 
    
 


【发表评论】 【进入论坛】【关闭页面】
相关文章