《Nature》目录要览(2009年6月11日出版)

时间:2009-06-13  阅读:    我要评论:

 
《Nature》目录要览(2009年6月11日出版)
 
封面故事:观测日冕将不需等待日全食
Solar eclipses as an astrophysical laboratory
要对日冕进行有意义的观测,天文学家不再需要等日全食了。基于地球和卫星的日冕观测仪使得这种观测成了常规工作。但正如Jay Pasachoff在一篇Review文章(国际天文年系列约稿之一)中所解释的那样,新一代日食研究正在将从卫星上所进行的观察与地基观测从空间、时间以及光谱分辨率范畴(这样的分辨率太空中无法达到)上联系了起来。最终,随着基于太空的太阳望远镜数量增多,它们可能会完全替代基于地球的观测工作。但在今后6亿年左右(直到月球距太阳的距离增加到使其盘面太小、以至不能遮挡阳光的程度),日食仍将是地球上最壮观的景色之一。本期封面图片是由25幅图片组成的一个组合图,它所反映的是从蒙古所观测到的2008年8月1日日全食期间太阳的东半部分。(Review p. 789)Credit: © 2008 Miloslav Druckmüller, Martin Dietzel, Peter Aniol, Vojtech Rušin

七鳃鳗免疫系统与人类的相似之处(Double immunity in lampreys)
Dual nature of the adaptive immune system in lampreys
七鳃鳗和八目鳗(最后的无颌类脊椎动物)之所以吸引免疫学家注意,是因为它们的适应性免疫系统在灵活性上可与人类的相媲美。在人类身上,每个淋巴细胞表达针对某一种抗原的预期性受体,由可变的、多样的连接片段构成。无颌类脊椎动物利用由“富含亮氨酸重复序列”的蛋白片段组成的可变淋巴细胞受体,并有一个不可变的柄系在淋巴细胞表面上。对海生七鳃鳗所做的新的研究工作显示了更多与人类相似的地方:它们有一个分成不同腔室的适应性免疫系统,含有与哺乳动物适应性免疫系统中分泌细胞因子的T-细胞及分泌抗体的B-细胞相似的细胞。这表明,淋巴细胞分化沿类似T-细胞和B-细胞系方向上所发生的分歧在演化上出现的时间要比人们以前所认为的早得多,因而它们的系统不是我们人类自己免疫系统的一个先驱,就是同我们自己的免疫系统并行演化的。(Article p. 796; News & Views)


Sirtuins与寿命调控之间的关系(Sirtuins and longevity)
Histone H4 lysine 16 acetylation regulates cellular lifespan
“Sirtuins”(保守的“依赖于NAD+-的去乙酰化酶”或ADP-核糖转移酶)有助于很多生物延长寿命,尽管其中所涉及的机制还很不清楚。例如,酵母sirtuin Sir2已知能够使组蛋白H4的赖氨酸 -16残迹脱去乙酰基,但不清楚这是否与Sir2的抗衰老功能有关。现在,Dang等人报告了Sir2蛋白丰度与年龄相关的下降,这种下降与H4的赖氨酸 -16乙酰化和组蛋白的失去有关,使得从复制角度来讲比较老的酵母细胞中特定亚端粒区域转录沉默作用减弱。这一组蛋白乙酰化通道与关于酵母的现有衰老模型截然不同,可能代表着Sirtuins从演化角度来讲一个保守的功能,即通过使端粒染色质保持不变,来调控复制性衰老。(Article p. 802)

地球的可见光和近红外透射谱(Earth seen in a new light)
Earth's transmission spectrum from lunar eclipse observations
我们对太阳系外行星大气层极少认知中的一部分,是从来自这些行星之母恒星所发光的光谱中获得的,这种光在穿过恒星圆面时会通过行星的大气层。随着行星搜寻技术的发展,我们正在迅速逼近这样一个点:很可能发现与地球相似的星球。那么,我们在找什么呢?进行比较工作的一个好的出发点,将是我们自己星球的一个透射谱。现在我们有了这样一个透射谱,是根据对在一次月食期间从月球反射到地球的阳光进行定性获得的,这样一个情景类似于对一次行星凌日的几何特征进行观测。这种间接方法产生了地球的一个可见光和近红外透射谱。在反射谱中很弱的一些具有生物学意义的大气特征在透射谱中要强得多,比模型预测的结果要强。(Letter p. 814)

行星彼此之间相撞或与太阳相撞的可能性(Well did you ever…)
Existence of collisional trajectories of Mercury, Mars and Venus with the Earth
太阳系中行星轨道未来演化的数值模拟需要在非常大的尺度上来计算力,这主要是由于沿轨道运行的不同物质的相互依赖所产生的混沌因素。Jacques Laskar和 Mickael Gastineau利用每秒1万亿次浮点运算的JADE超级计算机来模拟关于太阳系在50亿年间演化情况的一组2,501个解,他们发现:这些解中1%导致水星的偏心率有很大增加,大到足以使其与金星或太阳相撞。令人吃惊的是,在一个高偏心率的解中,水星偏心率随后的下降诱导巨型行星的角动量发生转移,这种转移在大约33.4亿年后使所有陆地行星失去稳定,使水星、火星或金星有可能与地球相撞。(Letter p. 817; News & Views)

气候-碳敏感性与碳-气候响应(Climate–carbon sensitivity)
The proportionality of global warming to cumulative carbon emissions
迄今为止,描述和预测气候对由人类活动产生的二氧化碳排放的响应的工作都集中在气候敏感性上:与二氧化碳数量加倍相关的平衡温度变化。但最近的研究工作表明,这种“Charney”敏感性(根据1979年首先采用这种方法的气象学家Jule Charney命名)可能是对地球系统全面反应的一种不全面表征,因为它忽略了碳循环、气溶胶、土地利用和陆地覆盖的变化。Matthews等人提出关于气候系统对人类活动产生的二氧化碳排放的响应的一种新的度量,即碳-气候响应,或称CCR。他们将一个简化的气候模型、来自最近一次模型相互比较的一系列模拟结果以及历史上的约束因素结合起来,发现排放一万亿吨碳将引起1.0–2.1 ºC的全球变暖,而且与排放的时间点或大气中二氧化碳浓度无关,这个CCR值与对二十一世纪的模型预测结果是一致的。(Letter p. 829)

台东为什么很少发生大地震(An ill wind for slow earthquakes)
Slow earthquakes triggered by typhoons
由大地震产生的远震波已知会触发其他地震,即便相距很远,而且研究表明,季节性气压变化会调控微型地震活动。现在,Chiching Liu等人报告了一个出乎意料的地质现象:由天气状况诱发的地震。来自台湾东部钻孔应变仪的数据表明,慢地震(持续几小时、几分钟而不是几分钟、几秒钟的地震事件)可以由台风诱发。数值模型表明,与台风相关的慢压力导致断层发生一个非常小的脱夹,这种脱夹的应力一定很大,而且接近断裂。台东经受着非常高的压缩变形,但很少发生大地震。该地区重复发生的慢地震,其作用可能是使受应力区域分隔开来,抑制大地震的发生;大地震的发生需要长时间的连续地震断裂。(Letter p. 833)

多巴胺神经元的复杂性(Dopamine neuron complexity)
Two types of dopamine neuron distinctly convey positive and negative motivational signals
脑底部的多巴胺神经元是正常运动行为的关键,它们的损失会导致帕金森氏症等疾病。然而,多巴胺神经元的活性与身体运动无关,而是与奖励事件有关。最近的理论表明,多巴胺神经元作为一个同质的功能集团通过与奖励相关的信号来引导运动学习。现在,用对“正”刺激和“负”刺激做出巴甫洛夫条件反射的猴子所做的一项研究表明,多巴胺神经元比这一模型所暗示的异质性要更强一些。位于脑中稍有不同的区域中的不同类别的多巴胺神经元,对愉快的和不愉快的刺激有特定反应,对与这些事件相关的诱发刺激也有特定反应。这表明,多巴胺神经元在学习控制中的参与情况要更为复杂,它们所编码的信号也要比简单的奖励更为微妙。(Letter p. 837)

组蛋白与白血病的关系(Histones and leukaemia)
Haematopoietic malignancies caused by dysregulation of a chromatin-binding PHD finger
某些 “急性髓性白血病”(AML)患者中所见的染色体易位,会导致一种染色质结合蛋白的“PHD指”向一种核孔蛋白NUP98的融合。现在,研究人员发现这样一种融合蛋白是一种强力肿瘤蛋白,包括AML在内。向“PHD指”引入会使其放弃与在Lys4处发生三甲基化的组蛋白H3相结合的突变,将会阻断肿瘤发生。通过结合染色质,NUP98-PHD融合似乎会将有重要发育功能的基因锁定到一种活动状态。因此,抑制组蛋白修饰的一种“效应器”会导致肿瘤发生。(Letter p. 847)

Cdk1调控因子与监测细胞大小的机制之间的联系(A time to divide)
Polar gradients of the DYRK-family kinase Pom1 couple cell length with the cell cycle / A spatial gradient coordinates cell size and mitotic entry in fission yeast
当增生细胞因“依赖于周期蛋白的激酶”(Cdk1)的受控活性而达到一定大小时,它们会分裂,但Cdk1调控因子与监测细胞大小的机制之间的联系一直不是很清楚。本期Nature上两篇论文,描述了一种裂殖酵母激酶Pom1(已知是细胞极性的一个决定因子)何以能够在细胞内形成一个度量杆状细胞长度的极性梯度、以及何以能够通过对Cdk1抑制因子Wee1的负调控来诱导细胞分裂。(Letters pp. 852, 857)

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NEWS AND VIEWS
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Planetary science: The Solar System's extended shelf life pp781-782
Simulations show that orbital chaos can lead to collisions between Earth and
the inner planets. But Einstein's tweaks to Newton's theory of gravity render
these ruinous outcomes unlikely in the next few billion years.
Gregory Laughlin
doi:10.1038/459781a
http://www.nature.com/nature/journal/v459/n7248/full/459781a.html

Cell cycle: Cell division brought down to size pp782-783
Cells normally divide on reaching a fairly specific size, but how cell size
dictates the timing of cell division remains obscure. In fission yeast, a
spatial gradient of a cell-tip protein may provide an answer.
Kenneth E. Sawin
doi:10.1038/459782a
http://www.nature.com/nature/journal/v459/n7248/full/459782a.html

Ecology: Traits of plant invaders pp783-784
Many plants introduced to new habitats have fewer microbial pathogens than
when in their home range, and have the ability to grow rapidly. Such a
combination may make for especially troublesome immigrants.
Tim Seastedt
doi:10.1038/459783a
http://www.nature.com/nature/journal/v459/n7248/full/459783a.html

Immunology: Immunity's ancient arms pp784-786
Diverse receptors on two types of cell mediate adaptive immunity in jawed
vertebrates. In the lamprey, a jawless vertebrate, immunity is likewise
compartmentalized but the molecular mechanics are very different.
Gary W. Litman and John P. Cannon
doi:10.1038/459784a
http://www.nature.com/nature/journal/v459/n7248/full/459784a.html

50 & 100 years ago p785
doi:10.1038/459785a
http://www.nature.com/nature/journal/v459/n7248/full/459785a.html

Organic chemistry: Synthetic lessons from nature pp786-787
Most syntheses in organic chemistry target one molecule, or a few closely
related analogues at most. But by taking a leaf from nature's book, the
latest synthetic strategy opens the door to a whole family of compounds.
Huw M. L. Davies
doi:10.1038/459786a
http://www.nature.com/nature/journal/v459/n7248/full/459786a.html

Cell biology: The proteasome assembly line pp787-788
The assembly of the proteasome [mdash] the cellular machine that eliminates
unwanted proteins [mdash] is a carefully choreographed affair, involving a
complex sequence of steps overseen by dedicated protein chaperones.
Kiran Madura
doi:10.1038/459787a
http://www.nature.com/nature/journal/v459/n7248/full/459787a.html

----------------------
REVIEW
----------------------
Solar eclipses as an astrophysical laboratory pp789-795
Jay M. Pasachoff
doi:10.1038/nature07987
Abstract:
http://www.nature.com/nature/journal/v459/n7248/abs/nature07987.html
Article: http://www.nature.com/nature/journal/v459/n7248/full/nature07987.html

----------------------
ARTICLES
----------------------
Dual nature of the adaptive immune system in lampreys pp796-801
Peng Guo et al.
doi:10.1038/nature08068
Abstract:
http://www.nature.com/nature/journal/v459/n7248/abs/nature08068.html
Article: http://www.nature.com/nature/journal/v459/n7248/full/nature08068.html

Histone H4 lysine 16 acetylation regulates cellular lifespan pp802-807
Weiwei Dang et al.
doi:10.1038/nature08085
Abstract:
http://www.nature.com/nature/journal/v459/n7248/abs/nature08085.html
Article: http://www.nature.com/nature/journal/v459/n7248/full/nature08085.html

Flipping of alkylated DNA damage bridges base and nucleotide excision repair pp808-813
Julie L. Tubbs et al.
doi:10.1038/nature08076
Abstract:
http://www.nature.com/nature/journal/v459/n7248/abs/nature08076.html
Article: http://www.nature.com/nature/journal/v459/n7248/full/nature08076.html

----------------------
LETTERS
----------------------
Earth/'s transmission spectrum from lunar eclipse observations pp814-816
Enric Palle et al.
doi:10.1038/nature08050
Abstract:
http://www.nature.com/nature/journal/v459/n7248/abs/nature08050.html
Article: http://www.nature.com/nature/journal/v459/n7248/full/nature08050.html

Existence of collisional trajectories of Mercury, Mars and Venus with the Earth pp817-819
J. Laskar and M. Gastineau
doi:10.1038/nature08096
Abstract:
http://www.nature.com/nature/journal/v459/n7248/abs/nature08096.html
Article: http://www.nature.com/nature/journal/v459/n7248/full/nature08096.html

Direct observation of a widely tunable bandgap in bilayer graphene pp820-823
Yuanbo Zhang et al.
doi:10.1038/nature08105
Abstract:
http://www.nature.com/nature/journal/v459/n7248/abs/nature08105.html
Article: http://www.nature.com/nature/journal/v459/n7248/full/nature08105.html

Total synthesis of eudesmane terpenes by site-selective C-H oxidations pp824-828
Ke Chen and Phil S. Baran
doi:10.1038/nature08043
Abstract:
http://www.nature.com/nature/journal/v459/n7248/abs/nature08043.html
Article: http://www.nature.com/nature/journal/v459/n7248/full/nature08043.html

The proportionality of global warming to cumulative carbon emissions pp829-832
H. Damon Matthews, Nathan P. Gillett, Peter A. Stott and Kirsten Zickfeld
doi:10.1038/nature08047
Abstract:
http://www.nature.com/nature/journal/v459/n7248/abs/nature08047.html
Article: http://www.nature.com/nature/journal/v459/n7248/full/nature08047.html

Slow earthquakes triggered by typhoons pp833-836
ChiChing Liu, Alan T. Linde and I. Selwyn Sacks
doi:10.1038/nature08042
Abstract:
http://www.nature.com/nature/journal/v459/n7248/abs/nature08042.html
Article: http://www.nature.com/nature/journal/v459/n7248/full/nature08042.html

Two types of dopamine neuron distinctly convey positive and negative motivational signals pp837-841
Masayuki Matsumoto and Okihide Hikosaka
doi:10.1038/nature08028
Abstract:
http://www.nature.com/nature/journal/v459/n7248/abs/nature08028.html
Article: http://www.nature.com/nature/journal/v459/n7248/full/nature08028.html

Specificity of sensory-motor connections encoded by Sema3e-Plxnd1 recognition pp842-846
Eline Pecho-Vrieseling et al.
doi:10.1038/nature08000
Abstract:
http://www.nature.com/nature/journal/v459/n7248/abs/nature08000.html
Article: http://www.nature.com/nature/journal/v459/n7248/full/nature08000.html

Haematopoietic malignancies caused by dysregulation of a chromatin-binding PHD finger
Gang G. Wang et al.
doi:10.1038/nature08036
Abstract:
http://www.nature.com/nature/journal/vaop/ncurrent/full/nature08036.html
Article: http://www.nature.com/nature/journal/vaop/ncurrent/full/nature08036.html

Polar gradients of the DYRK-family kinase Pom1 couple cell length with the cell cycle pp852-856
Sophie G. Martin and Martine Berthelot-Grosjean
doi:10.1038/nature08054
Abstract:
http://www.nature.com/nature/journal/v459/n7248/abs/nature08054.html
Article: http://www.nature.com/nature/journal/v459/n7248/full/nature08054.html

A spatial gradient coordinates cell size and mitotic entry in fission yeast pp857-860
James B. Moseley, Adeline Mayeux, Anne Paoletti and Paul Nurse
doi:10.1038/nature08074
Abstract:
http://www.nature.com/nature/journal/v459/n7248/abs/nature08074.html
Article: http://www.nature.com/nature/journal/v459/n7248/full/nature08074.html

Chaperone-mediated pathway of proteasome regulatory particle assembly
Jeroen Roelofs et al.
doi:10.1038/nature08063
Abstract:
http://www.nature.com/nature/journal/v459/n7248/abs/nature08063.html
Article: http://www.nature.com/nature/journal/v459/n7248/full/nature08063.html

Hexameric assembly of the proteasomal ATPases is templated through their C termini
Soyeon Park et al.
doi:10.1038/nature08065
Abstract:
http://www.nature.com/nature/journal/v459/n7248/abs/nature08065.html
Article: http://www.nature.com/nature/journal/v459/n7248/full/nature08065.html

An unusual carbon-carbon bond cleavage reaction during phosphinothricin biosynthesis pp871-874
Robert M. Cicchillo et al.
doi:10.1038/nature07972
Abstract:
http://www.nature.com/nature/journal/v459/n7248/abs/nature07972.html
Article: http://www.nature.com/nature/journal/v459/n7248/full/nature07972.html

----------------------
FUTURES
----------------------
Timed release p880
Clean thoughts.
David Marusek
doi:10.1038/459880a
http://www.nature.com/nature/journal/v459/n7248/full/459880a.html

----------------------
Advance Online Publication
----------------------
Bone-marrow adipocytes as negative regulators of the haematopoietic microenvironment
Olaia Naveiras et al.
doi:10.1038/nature08099
Abstract:
http://www.nature.com/nature/journal/vaop/ncurrent/full/nature08099.html
Article: http://www.nature.com/nature/journal/vaop/ncurrent/full/nature08099.html

Cyclic AMP intoxication of macrophages by a Mycobacterium tuberculosis adenylate cyclase
Nisheeth Agarwal et al.
doi:10.1038/nature08123
Abstract:
http://www.nature.com/nature/journal/vaop/ncurrent/full/nature08123.html
Article: http://www.nature.com/nature/journal/vaop/ncurrent/full/nature08123.html

07 June 2009
Subcellular homeostasis of phytohormone auxin is mediated by the ER-localized PIN5 transporter
Jozef Mravec et al.
doi:10.1038/nature08066
Abstract:
http://www.nature.com/nature/journal/vaop/ncurrent/full/nature08066.html
Article: http://www.nature.com/nature/journal/vaop/ncurrent/full/nature08066.html

Neural mechanisms of rapid natural scene categorization in human visual cortex
Marius V. Peelen, Li Fei-Fei and Sabine Kastner
doi:10.1038/nature08103
Abstract:
http://www.nature.com/nature/journal/vaop/ncurrent/full/nature08103.html
Article: http://www.nature.com/nature/journal/vaop/ncurrent/full/nature08103.html

A soma-to-germline transformation in long-lived Caenorhabditis elegans mutants
Sean P. Curran, Xiaoyun Wu, Christian G. Riedel and Gary Ruvkun
doi:10.1038/nature08106
Abstract:
http://www.nature.com/nature/journal/vaop/ncurrent/full/nature08106.html
Article: http://www.nature.com/nature/journal/vaop/ncurrent/full/nature08106.html

A mechanism linking extra centrosomes to chromosomal instability
Neil J. Ganem, Susana A. Godinho and David Pellman
doi:10.1038/nature08136
Abstract:
http://www.nature.com/nature/journal/vaop/ncurrent/full/nature08136.html
Article: http://www.nature.com/nature/journal/vaop/ncurrent/full/nature08136.html

10 May 2009
Haematopoietic malignancies caused by dysregulation of a chromatin-binding PHD finger
Gang G. Wang et al.
doi:10.1038/nature08036
Abstract:
http://www.nature.com/nature/journal/vaop/ncurrent/full/nature08036.html
Article: http://www.nature.com/nature/journal/vaop/ncurrent/full/nature08036.html                    
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