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2007年8月9日Nature中文摘要
 BIOX.CN  来源：生命经纬    2007年08月09日
封面故事：“能人”和“直立人”曾经共存了近50万年
Implications of new early Homo fossils from Ileret, east of Lake
Turkana, Kenya
类人猿“能人”（Homo habilis） 以及一般来说更大、时间更晚的“直立人”
（Homo erectus）经常被认为是同一进化分支上的两个点，其分别仅仅在时间
上。由于研究人员将来自格鲁吉亚Dmanisi的小型原始头骨解释为“形态上的中
间体”，这种观点得到了人们的进一步认可。但新的化石发现却讲述了一个不同
的故事。研究人员发现了一个特别小的“直立人”头骨和来自一个较晚的“能
人”化石的颌骨材料，而发现它们的环境表明，这两个物种在肯尼亚的Turkana
湖盆共存了近50万年时间。除了在时间上重叠外，“能人”和“直立人”在大小
上也重叠。“直立人”的高度性别二态性在这方面可能是一个因素。本期封面所
示为新发现的“直立人”化石（被称为KNM-ER 42700的部分颅骨），同时还有来
自坦桑尼亚的最大的非洲“直立人”OH 9。（Letter p. 688;
www.nature.com/podcast）（照片提供：F. Spoor， 肯尼亚国家博物馆）

药物重新发现方兴未艾（SECOND SITE）
New uses for old drugs
药物重新发现正在变成一大产业。由于将一种新药推向市场成本高昂，因此制药
公司正在重新审视它们旧的产品目录及过期的专利。Curtis R. Chong 和 David
J. Sullivan Jr解释说，对现有药物重新进行筛选，以寻找新的活性，是实验室
和诊所之间的一个很有价值的捷径。在发现对被忽略疾病的治疗方法上，全面筛
选工作很可能尤其有用。（Commentary p. 645）

茉莉酸信号通道的关键成分（Jasmonate and all that JAZ）
JAZ repressor proteins are targets of the SCFCOI1 complex during
jasmonate signaling / The JAZ family of repressors is the missing link
in jasmonate signalling
茉莉酸是一种羟脂（oxylipin），是茉莉香味中的主要成分。它是中央信号作用
成分尚未得到描述的最后一种主要植物激素。现在，从两个稍微不同的角度来研
究这个问题的两个小组已经揭开了这个谜团。Thines等人和Chini等人分别报告
说，JAsmonate Zim-domain (JAZ)蛋白家族的成员是茉莉酸信号通道的关键成
分。JAZ蛋白正常情况下抑制茉莉酸响应基因，但茉莉酸衍生物
jasmonoyl-isoleucine却将JAZ蛋白耦合到一个“泛素连接酶”（SCFCOI1）上，
从而确保它们的降解以及该信号通过基因表达的抑制所进行的传输。（Articles
pp. 661, 666; News & Views）

“量子铁磁流体”研究获得新成果（Quantum ferrofluids）
Strong dipolar effects in a quantum ferrofluid
本期Nature上一篇论文是关于超冷原子物理学中的一个热门话题的，那就是“量
子铁磁流体”，它们是由偏振的偶极子（电偶极子或磁偶极子）组成的超级流体
量子气体（superfluid quantum gases）。这种偶极子之间打破对称的相互作用
预计会导致新的物理现象。现在，来自斯图加特大学的一个研究小组用原子之间
的强各向异性磁性偶极子-偶极子相互作用成功生成了一个铬玻色-爱因斯坦凝聚
态，它诱使该气体云的纵横比发生显著变化。这种科学家苦寻的物质形式将使物
理体系的基础研究能够在以前尚未探索过的领域进行。（Letter p. 672; News
& Views）

现代版的牛顿“尘埃镜”实验（Dusting off an old technique）
Femtosecond time-delay X-ray holography
受牛顿曾经用来演示干涉的“尘埃镜”实验的启迪，Chapman等人设计了一个用
超快强X-射线脉冲来研究微粒的方法。牛顿的实验涉及可见光从一个背面镀银的
镜面前面的尘埃颗粒上的两次散射（一次进入镜面，一次从镜面出来），还涉及
相应的环形干涉图案。在现代版的这个实验中，X-射线脉冲聚焦在一个有聚苯乙
烯颗粒的薄膜上，放置在一个X-射线镜面之前。一个脉冲穿过样本，触发了一个
颗粒的爆炸，然后被镜面反射到样本上。所得到的衍射图案含有关于爆炸颗粒的
准确的时间和空间信息。这种类型的X-射线“flash”成像可用来在原子运动的
时间尺度上探索材料的三维动态。（Letter p. 676; News & Views;
www.nature.com/podcast）

上层温暖海水与下层冰冷海水发生混合的位置（Mixed message）
Intense mixing of lower thermocline water on the crest of the
Mid-Atlantic Ridge
海洋上层温暖的海水与下面较冷的海水的混合，是全球海洋环流中一个重要组成
部分，因为它能增加深水的浮力，但这种混合所发生的位置仍然不确定。Louis
St. Laurent 和 Andreas Thurnherr对当海水流经中大西洋山脊顶端一个狭窄通
道时所发生的海水混合现象进行了测量。他们所观测到的速度异乎寻常地高：如
果类似的混合速度发生在北大西洋海盆中的中大西洋山脊上的其他狭窄通道中，
那么这些地点对海水浮力增加的贡献就会像在这些通道的深度处该海盆其余地点
的总和那么大。所以，中海洋山脊上的狭窄通道（以前被忽略的地点）中所发生
的混合，对全球尺度上增加海水浮力的流量可能有一个相当可观的贡献。
（Letter p. 680; News & Views）

从地幔回到地表的物质的辨别（Earth to ocean）
The return of subducted continental crust in Samoan lavas
板块构造将化学富集的海洋壳和沉积物在俯冲带注射进地幔中。活跃的地幔混合
过程稀释和破坏了这些材料中的化学标记，所以当它们从地幔热柱中回到地表
时，它们将难以辨别。在萨摩亚海底熔岩中富集程度非常高的87Sr/86Sr 和
143Nd/144Nd同位素标记的发现将能帮助澄清这些问题。这些数据为在萨摩亚地
幔中循环的上层大陆壳的存在提供了明确证据，并且还支持认为循环的大陆壳物
质参与了地幔中在同位素组成上截然不同的地球化学库中其中一个（即所谓富集
的地幔“EM-2”成分）的形成的观点。（Letter p. 684; News & Views;
www.nature.com/podcast）

昆虫的生物多样性研究（Insects everywhere）
Low beta diversity of herbivorous insects in tropical forests / Host
specificity of Lepidoptera in tropical and temperate forests
昆虫是大多数生态系统中的主要力量，而在关于生物多样性的研究中它们却经常
没有鸟类、哺乳动物和植物受到的关注多。本期Nature上两篇论文改变了这种不
平衡状态。Novotny等人研究了巴布亚*新几内亚75,000平方公里雨林中的大约
500种鳞翅目毛虫、甲虫和果蝇。他们发现，食草昆虫的大多数种都广泛分布。
物种丰富度很高，这在热带很正常，但即便在数百公里距离内所发现的物种也没
有很大改变。Dyer等人从他们对从加拿大到巴西的地域范围内的蝴蝶和蛾幼虫的
数十万宿主特异性进食记录所做的研究得出了很不相同的结论。他们发现，一种
昆虫所食的树种的平均数量在热带要少于在“新世界”的温带部分，从而证实了
自达尔文和华莱士时代以来就被生物学家讨论很多的生态学中的纬度梯度。不
过，由于这两篇论文所得出的结果明显存在矛盾，所以这一讨论还将继续进行下
去。（Letters pp. 692, 696; News & Views）

瘙痒感的分子基础及其与痛感的区别（Technical itch）
A gastrin-releasing peptide receptor mediates the itch sensation in
the spinal cord
瘙痒的难受感是众所周知的，但其神经生物学基础却仍然不很清楚。现在，“瘙
痒通道”中的第一个分子层已经被识别出来。历史上，瘙痒曾被认为是痛感的一
种不太强烈的形式。但用基因剔除小鼠所做的研究表明，“释放胃泌素
（Gastrin）的肽受体”对于中枢神经系统的痒刺激（而不是痛刺激）很重要。
因此，该受体可能是开发不影响痛觉信号的抗瘙痒药物的一个目标。（Letter
p. 700）

泛素对神经退化疾病的普遍意义（Ubiquitin inclusions）
Global changes to the ubiquitin system in Huntington's disease
神经退化疾病“亨廷顿症”患者的神经元含有富含泛素的异常蛋白包容体。曾有
人提出，细胞泛素化和蛋白酶体降解系统中所发生的变化有助于这种疾病的发
生。对“亨廷顿症”患者大脑及这种疾病的几个小鼠模型所做的质谱分析，证实
了泛素链在蛋白包容体中始终存在，说明该系统功能的普遍丧失可能有助于这种
疾病的发生。 这些发现说明泛素可能用作一种诊断工具，而且由于泛素在神经
病理病灶中的异常积累还是阿尔茨海默氏症的一个特征，所以这些从神经学上来
看各不相同的疾病可能具有共同的基本分子特征。（Letter p. 704）

无脊椎动物的STDP现象（The memory of locusts）
Hebbian STDP in mushroom bodies facilitates the synchronous flow of
olfactory information in locusts
突触弹性（神经细胞之间联系的加强或减弱）已知在脊椎动物中依赖于输入信号
是在一个神经元的信号尖峰之前还是之后，这个现象被称为“尖峰时间依赖性弹
性”（STDP）。现在，Stijn Cassenaer 和Gilles Laurent首次在一种无脊椎动
物（即蝗虫）身上描述了STDP。他们的活体研究还表明，STDP是将感觉器官连接
到大脑中的记忆中心的神经通道上的嗅觉信息的神经编码得以保留下来的关键。
这一发现为了解昆虫脑中回路动态、架构和学习之间的关系提供了新线索。
（Letter p. 709; News & Views）



----------------------
NEWS AND VIEWS
----------------------
Femtophysics: Double vision pp651 - 652
By cunningly diffracting X-rays twice from an exploding
nanometre-scale sphere, holographic images can be made of a tiny
system evolving at lightning speed. The technique could be used to
picture atomic dynamics.
Andrea Cavalleri
doi:10.1038/448651a
http://www.nature.com/nature/journal/v448/n7154/full/448651a.html

Systems neuroscience: Timing is everything pp652 - 654
Interactions among neurons in brain circuits underlie sensory
perception and information storage. Work in locusts shows how the
timing of different neuronal signals is synchronized to ensure
effective communication.
Phillip Larimer and Ben W. Strowbridge
doi:10.1038/448652a
http://www.nature.com/nature/journal/v448/n7154/full/448652a.html

50 & 100 Years Ago p653
doi:10.1038/448653a
http://www.nature.com/nature/journal/v448/n7154/full/448653a.html

Chemical biology: Ions illuminated pp654 - 655
Calcium ions act as signals between cells, but their exact locations
― at the nanometre scale ― have been difficult to pinpoint. The
latest biosensor promises to reveal these details in dynamic living
systems.
Christopher J. Chang
doi:10.1038/448654a
http://www.nature.com/nature/journal/v448/n7154/full/448654a.html

Geochemistry: The lost continents pp655 - 656
Once subducted into the mantle, material from Earth's continental
crust seems to disappear. But its distinctive isotopic signature has
been found back at the surface ― in volcanic rocks on a Pacific
island.
Albrecht W. Hofmann
doi:10.1038/448655a
http://www.nature.com/nature/journal/v448/n7154/full/448655a.html

Electrostatics: Colour discrimination p656
Richard Webb
doi:10.1038/448656a
http://www.nature.com/nature/journal/v448/n7154/full/448656a.html

Biodiversity: World of insects pp657 - 658
When it comes to understanding patterns of biodiversity, ours is a
little-known planet. Large-scale sampling projects, as carried out in
two investigations of insect diversity, show a way forward.
Nigel E. Stork
doi:10.1038/448657a
http://www.nature.com/nature/journal/v448/n7154/full/448657a.html

Crystallography: A down-to-Earth approach pp658 - 659
In seeking out ideal conditions for growing protein crystals,
solutions have increasingly been found in the low-gravity conditions
of space. But answers might be lurking in fields closer to home.
John R. Helliwell and Naomi E. Chayen
doi:10.1038/448658a
http://www.nature.com/nature/journal/v448/n7154/full/448658a.html

Plant biology: Jasmonate perception machines pp659 - 660
How do plant cells respond so vigorously to organisms that damage
their cells? Following on from progress made in understanding hormonal
control of growth and development comes news of how a plant's security
system operates.
Edward E. Farmer
doi:10.1038/448659a
http://www.nature.com/nature/journal/v448/n7154/full/448659a.html

Correction p660
doi:10.1038/448660a
http://www.nature.com/nature/journal/v448/n7154/full/448660a.html

----------------------
LETTERS
----------------------
Strong dipolar effects in a quantum ferrofluid pp672 - 675
This paper reports the realization of a chromium Bose-Einstein
condensate (BEC) with strong anisotropic magnetic dipole-dipole
interaction between the atoms, which induces a pronounced change of
the aspect ratio of the cloud. The experiment opens the way for
exploration of the unique properties of quantum ferrofluids.
Thierry Lahaye et al.
doi:10.1038/nature06036
Abstract:
http://www.nature.com/nature/journal/v448/n7154/abs/nature06036.html
Article:
http://www.nature.com/nature/journal/v448/n7154/full/nature06036.html

Femtosecond time-delay X-ray holography pp676 - 679
A modern version of Newton's 'dusty 'mirror' experiment is made,
whereby X-ray pulses are focused on a thin membrane with polystyrene
particles placed in front of an X-ray mirror. After a pulse traverses
through the sample, triggering the explosion of a particle, it is
reflected back on to the sample by the mirror to probe this reaction.
The resulting diffraction pattern contains accurate time and spatially
resolved information about the exploding particles.
Henry N. Chapman et al.
doi:10.1038/nature06049
Abstract:
http://www.nature.com/nature/journal/v448/n7154/abs/nature06049.html
Article:
http://www.nature.com/nature/journal/v448/n7154/full/nature06049.html

Intense mixing of lower thermocline water on the crest of the
Mid-Atlantic Ridge pp680 - 683
Observations from the crest of the Mid-Atlantic Ridge suggest that
passages in rift valleys and ridge-flank canyons provide the most
energetic sites for oceanic turbulence. Measurements show that large
diffusivities characterize the mixing downstream of a sill in a well
stratified boundary layer, with mixing levels remaining of the order
of 10-4m2 s-1 at the base of the main thermocline.
Louis C. St Laurent and Andreas M. Thurnherr
doi:10.1038/nature06043
Abstract:
http://www.nature.com/nature/journal/v448/n7154/abs/nature06043.html
Article:
http://www.nature.com/nature/journal/v448/n7154/full/nature06043.html

The return of subducted continental crust in Samoan lavas pp684
- 687
Enriched 87Sr/86Sr and 143Nd/144Nd isotope signatures are reported in
submarine Samoan lavas. The data provide clear evidence for the
presence of recycled upper continental crust in the Samoan mantle, and
also support the idea that recycled continental material is involved
in the formation of one of the mantle's isotopically-distinct
geochemical reservoirs, the so-called enriched mantle 2.
Matthew G. Jackson et al.
doi:10.1038/nature06048
Abstract:
http://www.nature.com/nature/journal/v448/n7154/abs/nature06048.html
Article:
http://www.nature.com/nature/journal/v448/n7154/full/nature06048.html

Implications of new early Homo fossils from Ileret, east of Lake
Turkana, Kenya pp688 - 691
Two new cranial fossils found in Kenya have bearing on the
relationship between Homo habilis and Homo erectus. Descriptions of a
small H. erectus skull, and jaw material from a late-surviving
specimen of Homo habilis demonstrate that the two species co-existed
in the Lake Turkana basin in Kenya for almost half a million years.
F. Spoor et al.
doi:10.1038/nature05986
Abstract:
http://www.nature.com/nature/journal/v448/n7154/abs/nature05986.html
Article:
http://www.nature.com/nature/journal/v448/n7154/full/nature05986.html

Low beta diversity of herbivorous insects in tropical forests pp692
- 695
A study of about 500 species of lepidopteran caterpillars, beetles and
fruit flies details that that most species of herbivorous insects are
widely distributed over 75,000 km2 of contiguous lowland rain forest
in Papua New Guinea. Thus, although species richness was high, the
species found did not alter much even over hundreds of kilometres
despite habitat discontinuities and different geological terrains.
Vojtech Novotny et al.
doi:10.1038/nature06021
Abstract:
http://www.nature.com/nature/journal/v448/n7154/abs/nature06021.html
Article:
http://www.nature.com/nature/journal/v448/n7154/full/nature06021.html

Host specificity of Lepidoptera in tropical and temperate
forests pp696 - 699
Larval diets of tropical Lepidoptera are more specialized than those
of their temperate forest counterparts: tropical species on average
feed on fewer plant species, genera and families than do temperate
caterpillars. This results in a greater turnover in caterpillar
species composition between tree species in tropical faunas than in
temperate faunas, and it is suggested that greater specialization in
tropical faunas is the result of differences in trophic interactions.
L. A. Dyer et al.
doi:10.1038/nature05884
Abstract:
http://www.nature.com/nature/journal/v448/n7154/abs/nature05884.html
Article:
http://www.nature.com/nature/journal/v448/n7154/full/nature05884.html

Global changes to the ubiquitin system in Huntington's disease pp704
- 708
Mass spectrometry is used to systematically analyse the brains of
patients suffering from Huntingdon's disease, as well as several mouse
models of the disease, for the presence of ubiquitin chains. In all
cases, an accumulation of ubiquitin chains was found, suggesting that
a general dysfunction of this system may contribute to the disease
process.
Eric J. Bennett et al.
doi:10.1038/nature06022
Abstract:
http://www.nature.com/nature/journal/v448/n7154/abs/nature06022.html
Article:
http://www.nature.com/nature/journal/v448/n7154/full/nature06022.html

DNMT3L connects unmethylated lysine 4 of histone H3 to de novo
methylation of DNA pp714 - 717
DNMT3L, a regulatory factor related in sequence to DNA
methyltransferases, is shown to interact with the N terminus of
histone H3 and this interaction is inhibited by methylation at lysine
4. This suggests DNMT3L could respond to states of histone
modification to regulate de novo DNA methylation.
Steen K. T. Ooi et al.
doi:10.1038/nature05987
Abstract:
http://www.nature.com/nature/journal/v448/n7154/abs/nature05987.html
Article:
http://www.nature.com/nature/journal/v448/n7154/full/nature05987.html

Recognition of unmethylated histone H3 lysine 4 links BHC80 to
LSD1-mediated gene repression pp718 - 722
BHC80 is a component of the LSD1 co-repressor complex that
demethylates histone H3 at lysine 4. The PHD domain of BHC80 interacts
with the histone H3 tail only when lysine 4 is unmethylated, and BHC80
function is coupled to that of LSD1 in gene repression.
Fei Lan et al.
doi:10.1038/nature06034
Abstract:
http://www.nature.com/nature/journal/v448/n7154/abs/nature06034.html
Article:
http://www.nature.com/nature/journal/v448/n7154/full/nature06034.html
 
    
 


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