《自然》（20181018出版）一周论文导读

Volume 562 Issue7727, 18 October 2018

2018年10月18日第562卷7727期

动物学Zoology

Elucidating thecontrol and development of skin patterning in cuttlefish

透过皮肤“看穿”墨鱼的想法

▲作者：Sam Reiter, Philipp Hülsdunk, Theodosia Woo, Gilles Laurent,et al.

▲相关链接：

https://www.nature.com/articles/s41586-018-0591-3

▲导读：墨鱼和章鱼具有一种无与伦比的能力——改变皮肤的颜色和纹理外观，以便伪装或交流，而这要归功于无数色素细胞的有控制的挤压。

跟踪这些色素细胞的扩张状态，可以定量描述墨鱼的实时知觉状态，甚至有望成为神经描述代替指标。

作者开发了相关计算方法和分析方法，从自由行动的墨鱼身上获取这些信息。

作者用了几周的时间拍摄水箱中的6只墨鱼，并以每秒60帧的帧速率在单细胞尺度上对墨鱼背侧外套膜的色素细胞进行了颜色分类。

他们还在墨鱼上方移动手的位置，使之经历由暗到明的过程，由此追踪墨鱼的动态变化。

作者多次重复这一过程，并报告称墨鱼每一次受到刺激时都产生相同的目标模式。

研究结果能够客观描述复杂的知觉行为，并且这种方法可以带来有关神经系统背后的组织原则的见解。

▲Abstract：Few animals providea readout that is as objective of their perceptual state as camouflagingcephalopods. Their skin display system includes an extensive array of pigmentcells (chromatophores), each expandable by radial muscles controlled by motorneurons. If one could track the individual expansion states of thechromatophores, one would obtain a quantitative description—and potentiallyeven a neural description by proxy—of the perceptual state of the animal inreal time. Here we present the use of computational and analytical methods toachieve this in behaving animals, quantifying the states of tens of thousandsof chromatophores at sixty frames per second, at single-cell resolution, andover weeks. We infer a statistical hierarchy of motor control, reveal anunderlying low-dimensional structure to pattern dynamics and uncover rules thatgovern the development of skin patterns. This approach provides an objectivedescription of complex perceptual behaviour, and a powerful means to uncoverthe organizational principles that underlie the function, dynamics andmorphogenesis of neural systems.

图片来源：NATURE

医学Medical science

Functional genomiclandscape of acute myeloid leukaemia

急性髓性白血病的药物敏感性

▲作者：Jeffrey W. Tyner, Cristina E. Tognon, Brian J. Druker, et al. 

▲ 相关链接：

https://www.nature.com/articles/s41586-018-0623-z

▲导读：急性髓性白血病是一种非常多样化的疾病，其复杂的突变模式使得要开发有效的药物疗法变得颇具挑战性。

作者报告了Beat AML项目（包含了562名AML患者的672例肿瘤活检的数据集）的初步结果。

作者发现了以前未在AML中观察到的新突变，以及突变和药物治疗反应之间的关联。

例如，观察到FLT3、NPM1和DNMT3A基因突变与依鲁替尼药物敏感性之间存在显著关联，这表明携带这些基因的突变版本（特别是FLT3）的患者可能对该特定疗法更敏感。

研究结果与未来基于该数据集的其他发现可能带来治疗AML的临床新方法。

▲Abstract: The implementationof targeted therapies for acute myeloid leukaemia (AML) has been challengingbecause of the complex mutational patterns within and across patients as wellas a dearth of pharmacologic agents for most mutational events. Here we reportinitial findings from the Beat AML programme on a cohort of 672 tumourspecimens collected from 562 patients. We assessed these specimens usingwhole-exome sequencing, RNA sequencing and analyses of ex vivo drugsensitivity. Our data reveal mutational events that have not previously beendetected in AML. We show that the response to drugs is associated withmutational status, including instances of drug sensitivity that are specific tocombinatorial mutational events. Integration with RNA sequencing also revealedgene expression signatures, which predict a role for specific gene networks inthe drug response. Collectively, we have generated a dataset—accessible throughthe Beat AML data viewer (Vizome)—that can be leveraged to address clinical,genomic, transcriptomic and functional analyses of the biology of AML.

Cervical excitatoryneurons sustain breathing after spinal cord injury

颈兴奋神经元有助在脊髓损伤后维持呼吸

▲作者：Kajana Satkunendrarajah, Spyridon K. Karadimas, Michael G. Fehlings, etal. 

▲ 相关链接：

https://www.nature.com/articles/s41586-018-0595-z

▲ 导读：呼吸功能障碍是颈椎创伤性脊髓损伤后发病和死亡的主要原因，常常需要辅助通气，因此需要制定恢复呼吸的策略。

作者在不同脊柱损伤模型中结合使用药物基因学和呼吸生理学分析，研究表明，颈椎中部兴奋性中间神经元的维护对维持非创伤性颈脊髓损伤小鼠的呼吸非常重要，同时对创伤性脊髓损伤后促进呼吸复苏也非常重要。

虽然这些中间神经元对于正常情况下的呼吸并非必要，但对未受伤动物体内的中间神经元进行刺激可以提高吸气幅度。

脊髓损伤后，通过药物立即刺激颈兴奋中间神经元可恢复呼吸运动功能。

总的来说，研究结果展示了一种通过靶向神经元亚群恢复中枢神经系统损伤后呼吸的策略。

▲Abstract：Dysfunctional breathing is themain cause of morbidity and mortality after traumatic injury of the cervicalspinal cord and often necessitates assisted ventilation, thus stressing theneed to develop strategies to restore breathing. Here, using a combination ofpharmacogenetics and respiratory physiology assays in different models ofspinal cord injury, we show that mid-cervical excitatory interneurons areessential for the maintenance of breathing in mice with non-traumatic cervicalspinal cord injury, and are also crucial for promoting respiratory recoveryafter traumatic spinal cord injury. Although these interneurons are notnecessary for breathing under normal conditions, their stimulation innon-injured animals enhances inspiratory amplitude. Immediately after spinalcord injury, pharmacogenetic stimulation of cervical excitatory interneuronsrestores respiratory motor function. Overall, our results demonstrate astrategy to restore breathing after central nervous system trauma by targeting aneuronal subpopulation.

图1:退行性颈椎病ntSCI患者的颈椎核磁共振成像。

植物科学Plant sciences

A separated vortexring underlies the flight of the dandelion

蒲公英种子的飞行

▲作者：Cathal Cummins, Madeleine Seale, Alice Macente, Naomi Nakayama, etal.  

▲ 相关链接：

https://www.nature.com/articles/s41586-018-0604-2

▲ 导读：蒲公英利用冠毛（小绒毛）帮助种子飞行扩散。

冠毛会延缓种子的降落，使种子飞行的距离超过水平风吹送的距离，冠毛或许还可以影响种子降落的方向。

然而，目前尚不清楚为什么羽状种子（如蒲公英）长有冠毛而不是翼状膜。作者构建了一个垂直风洞，对自由飞行的和固定的蒲公英种子的绕流做可视化处理。

通过长曝光摄影和高速成像，作者发现了一个稳定的气泡——涡环，它与种子本体分离，但稳定地保持在冠毛下部固定距离的位置。

不仅如此，蒲公英冠毛的孔隙度似乎受到精确地调控以稳定涡环，并且与实心盘相比，冠毛产生的单位面积阻力是其4倍以上。

作者认为这使得羽状设计比翼状膜能更有效地扩散轻盈的种子。

▲Abstract: Wind-dispersedplants have evolved ingenious ways to lift their seeds. The common dandelionuses a bundle of drag-enhancing bristles (the pappus) that helps to keep theirseeds aloft. This passive flight mechanism is highly effective, enabling seeddispersal over formidable distances; however, the physics underpinningpappus-mediated flight remains unresolved. Here we visualized the flow arounddandelion seeds, uncovering an extraordinary type of vortex. This vortex is aring of recirculating fluid, which is detached owing to the flow passingthrough the pappus. We hypothesized that the circular disk-like geometry andthe porosity of the pappus are the key design features that enable theformation of the separated vortex ring. The porosity gradient was surveyedusing microfabricated disks, and a disk with a similar porosity was found to beable to recapitulate the flow behaviour of the pappus. The porosity of thedandelion pappus appears to be tuned precisely to stabilize the vortex, whilemaximizing aerodynamic loading and minimizing material requirements. Thediscovery of the separated vortex ring provides evidence of the existence of anew class of fluid behaviour around fluid-immersed bodies that may underlielocomotion, weight reduction and particle retention in biological and manmadestructures.

图片来源：NATURE

考古学Archeology

Reassessing evidenceof life in 3,700-million-year-old rocks of Greenland

最早化石证据引争议

▲作者：Abigail C. Allwood, Minik T. Rosing, Christopher M. Heirwegh, et al.

▲ 相关链接：

https://www.nature.com/articles/s41586-018-0604-2

▲ 导读：地球上最古老的岩石发现于格陵兰岛，是寻找最早生命迹象的主要目标。

2016年，有研究人员在《自然》上发文，描述了在格陵兰岛西南部的岩石中发现的37亿年前的锥形结构，每个结构高1至4厘米。

他们认为这些是叠层石（由单细胞微生物在浅水中形成的层状沉积物），这一发现意味着化石记录的开始时间比先前预期的要早两亿年。

作者分析了上述化石的三维形状、方向和化学成分，结果发现这些结构和叠层石不一样，它们没有内部分层，缺乏微生物活动的化学标记，而且通过三维观察发现它们实际上是脊形，而不是圆锥形。

他们认为这些特征更适合解读为非生物源——海洋沉积物在被埋后长期变质和变形的结果。

这一发现不仅增加了人们对地球早期生命的理解，而且突出了综合三维分析对于在其他地方（如火星）寻找类似生命的重要性。

▲Abstract：The Palaeoarcheansupracrustal belts in Greenland contain Earth’s oldest rocks and are a primetarget in the search for the earliest evidence of life on Earth. A recent studyof 3,700-million-year-old rocks of the Isua supracrustal belt in Greenlanddescribed a rare zone in which low deformation and a closed metamorphic systemallowed preservation of primary sedimentary features, including putativeconical and domical stromatolites1 (laminated accretionary structures formed bymicrobially mediated sedimentation). The morphology, layering, mineralogy,chemistry and geological context of the structures were attributed to theformation of microbial mats in a shallow marine environment by 3,700 millionyears ago, at the start of Earth’s rock record. Here we report new researchthat shows a non-biological, post-depositional origin for the structures.Three-dimensional analysis of the morphology and orientation of the structureswithin the context of host rock fabrics, combined with texture-specificanalyses of major and trace element chemistry, show that the ‘stromatolites’are more plausibly interpreted as part of an assemblage of deformation structuresformed in carbonate-altered metasediments long after burial. The investigationof the structures of the Isua supracrustal belt serves as a cautionary tale inthe search for signs of past life on Mars, highlighting the importance ofthree-dimensional, integrated analysis of morphology, rock fabrics andgeochemistry at appropriate scales.

图片来源：NATURE

 

物理学Physics

Space-borneBose–Einstein condensation for precision interferometry

在太空中创造玻色—爱因斯坦凝聚

▲ 作者：Dennis Becker,  Maike D. Lachmann,Ernst M. Rasel, et al.

▲ 相关链接：

https://www.nature.com/articles/s41586-018-0605-1

▲ 导读：玻色—爱因斯坦凝聚是低密度原子气体冷却到接近绝对零度并且坍缩成非常致密的量子态时形成的物质状态。

研究玻色—爱因斯坦凝聚等量子系统有助于增加人们对引力波、广义相对论和量子力学的理解。

作者在探测火箭任务MAIUS-1（微重力下的物质波干涉测量）上创造了第一个自由落体天基玻色—爱因斯坦凝聚。

它与地基玻色—爱因斯坦凝聚相当，在1.6秒内产生约10^5个原子，而且作者在6分钟的太空飞行中能够进行80多次实验。

这些实验有助于增加人们对于在太空进行冷原子实验的理解，并且有望为量子气体实验开辟一个新时代。

▲Abstract： Because Bose–Einstein condensateshave an extremely low expansion energy, space-borne atom interferometers basedon Bose–Einstein condensation have the potential to have much greatersensitivity to inertial forces than do similar ground-based interferometers.Here we report on experiments conducted during the six minutes of in-spaceflight in which we studied the phase transition from a thermal ensemble to aBose–Einstein condensate and the collective dynamics of the resultingcondensate. Our results provide insights into conducting cold-atom experimentsin space, such as precision interferometry, and pave the way to miniaturizingcold-atom and photon-based quantum information concepts for satellite-basedimplementation. In addition, space-borne Bose–Einstein condensation opens upthe possibility of quantum gas experiments in low-gravity conditions.

Fig. 1: Set-up forspace-borne Bose–Einstein condensation.

图1:玻色-爱因斯坦凝聚装置

Thedispersion–brightness relation for fast radio bursts from a wide-field survey

快速射电暴的色散与亮度间存在关联

▲作者：R. M. Shannon, J.-P. Macquart, C. J. Riseley, et al.

▲相关链接：

https://www.nature.com/articles/s41586-018-0588-y

▲ 导读：尽管在过去10年中做出了相当大的努力，但到目前为止报道过的快速射电暴（来自银河系以外的强烈无线电发射）只有34次。

研究人员使用不同灵敏度的望远镜在一定的射电频率范围内以及受到人类活动不同程度的无线电频率干扰的环境中，进行了各种各样的搜索。

由于爆炸位置和亮度的不确定性，使得搜索变得更加复杂。作者报告了对这些射电暴进行的控制良好的宽视场射电巡视。

他们发现了20次射电暴，它们在首次检测后185 ~1097小时的随后观察中均未重复。

该样本包括迄今为止检测到的最近的和能量最高的爆炸。

该调查表明，爆发时光的色散和亮度之间存在关系，高通量暴发与在高灵敏度、窄视场巡视中发现的距离较远的射电暴事件类似。

▲ Abstract: Despite considerableefforts over the past decade, only 34 fast radio bursts—intense bursts of radioemission from beyond our Galaxy—have been reported. Attempts to understand thepopulation as a whole have been hindered by the highly heterogeneous nature ofthe searches, which have been conducted with telescopes of differentsensitivities, at a range of radio frequencies, and in environments corruptedby different levels of radio-frequency interference from human activity.Searches have been further complicated by uncertain burst positions andbrightnesses. Here we report a well controlled, wide-field radio survey forthese bursts. We found 20, none of which repeated during follow-up observationsbetween 185–1,097 hours after the initial detections. The sample includes boththe nearest and the most energetic bursts detected so far. The surveydemonstrates that there is a relationship between burst dispersion andbrightness and that the high-fluence bursts are the nearby analogues of themore distant events found in higher-sensitivity, narrower-field surveys.

澳大利帕克斯望远镜在2001年探测到第一次快速射电暴。

图片来源：Wayne England

加拿大探寻快速射电暴的射电望远镜CHIME。

图片来源：CHIMECollaboration

 

气候科学Climate science

Glacial expansion ofoxygen-depleted seawater in the eastern tropical Pacific

热带太平洋东部冰川时代缺氧海水扩张

▲作者：Babette A. A. Hoogakker, Zunli Lu, Natalie Umling, Eric Galbraith,et al.

▲ 相关链接：

https://www.nature.com/articles/s41586-018-0589-x

▲ 导读：海洋碳储量的增加被认为是解释冰河时代大气中二氧化碳浓度降低的一种机制；然而，目前尚未找到这种存储的明确特征。

海洋沉积物代理记录表明，在上一个冰河时代，深海中的氧气浓度的确较低，但太平洋近表面和中间水域（其中很大一部分目前氧含量很低）在冰川时期通常氧含量更高。

这种垂直对立可能意味着碳储存的最低净海盆综合变化。在此，作者采用双代理方法，将定性的上层水柱和定量的下层水氧相结合，以约束自上一个冰河世纪以来热带太平洋东部低氧水域垂直范围的变化。

作者的双重代理重建提供的证据表明，在最后一次冰川时期，太平洋东部的缺氧在向下扩张，而且没有迹象表明水柱上层有更多的氧气。

为此，作者推断其定量深水氧重建表明，冰川时代太平洋的呼吸碳库显著增加，将其作为耦合机制的重要组成部分，导致了冰川期间大气二氧化碳处于较低水平。

▲Abstract: Increased storage of carbon in the oceans has been proposed as amechanism to explain lower concentrations of atmospheric carbon dioxide duringice ages; however, unequivocal signatures of this storage have not been found.Marine sediment proxy records have suggested that oxygen concentrations in thedeep ocean were indeed lower during the last ice age, but that near-surface andintermediate waters of the Pacific Ocean—a large fraction of which are poorlyoxygenated at present—were generally better oxygenated during the glacial Thisvertical opposition could suggest a minimal net basin-integrated change incarbon storage. Here we apply a dual-proxy approach, incorporating qualitativeupper-water-column and quantitative bottom-water oxygen reconstructions, toconstrain changes in the vertical extent of low-oxygen waters in the easterntropical Pacific since the last ice age. Our tandem proxy reconstructionsprovide evidence of a downward expansion of oxygen depletion in the easternPacific during the last glacial, with no indication of greater oxygenation inthe upper reaches of the water column. We extrapolate our quantitativedeep-water oxygen reconstructions to show that the respired carbon reservoir ofthe glacial Pacific was substantially increased, establishing it as animportant component of the coupled mechanism that led to low levels ofatmospheric carbon dioxide during the glacial.

（晋楠）

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