《科學》（20181116出版）一周論文導讀

16 NOVEMBER 2018VOL 362, ISSUE 6416

天文學Astronomy

Large galaxy found lurking on the MilkyWay"s far side

隱藏在銀河系遠端的大星系

作者：Adam Mann

鏈接：

摘要：

繞著我們的星系旋轉的是一個鬼鬼祟祟的「巨人」。天文學家發現了一個名為Antlia 2的矮星系，它的大小是銀河系的1/3。

雖然，Antlia 2與大麥哲倫星雲(銀河系最大的「同伴」)一樣大，但它比麥哲倫星雲微弱一萬倍，因此人們直到現在才發現這個「低調的鄰居」。

而這個奇怪的星系挑戰了星系形成和暗物質模型。暗物質是一種看不見的物質，可以幫助星系聚集在一起。

這一星系是研究人員通過分析歐洲航天局蓋亞衛星的數據發現的。

蓋亞衛星主要用來測量銀河系內外10億顆恆星的運動和性質。

Abstract

Circling our galaxy is a stealthy giant. Astronomers have discovered a dwarf galaxy, called Antlia 2, that is one-third the size of the Milky Way itself. As big as the Large Magellanic Cloud, the galaxy"s largest companion, Antlia 2 eluded detection until now because it is 10,000 times fainter. Such a strange beast challenges models of galaxy formation and dark matter, the unseen stuff that helps pull galaxies together. The galaxy was discovered with data from the European Space Agency"s Gaia satellite, a space telescope measuring the motions and properties of 1 billion stars in and around the Milky Way.

The multiplemerger assembly of a hyperluminous obscured quasar at redshift 4.6

星系多重合併催生蒙塵類星體

作者：T. Díaz-Santos、R.J. Assef、A. W. Blain、M. Aravena、D.Stern、C.-W. Tsai、P. Eisenhardt、J.Wu、H. D. Jun，et al

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摘要：

在早期宇宙中，星系合併為形成被星塵遮蔽的類星體提供了原材料。

相關分析還揭示了非常明亮的星系是如何同時給其中心的超級巨大黑洞提供原料並用星塵將其遮蓋的。

天文學家先前發現了一群遠方的被星塵遮蔽的強力類星體，但對它們是如何形成的則一直不清楚。

研究人員用阿塔卡馬大型毫米波/亞毫米波陣列（ALMA）望遠鏡分析了這類遮蔽星塵類星體中的一顆。

他們在亞毫米波長觀察到了被稱作WISE J224607.57?052635.0的遮蔽星塵的類星體。他們的分析（包括星塵輻射）揭示了與該類星體通過氣體和星塵橋接的3個小型的伴星系。

進一步的研究揭示了這些伴星系與光亮中央類星體間的動態互動。

研究人員推斷，驅動星系合併的鄰近星系的吸積是一種催化機制，不僅為類星體供能，還提供了遮蔽類星體的星塵。

Abstract

Galaxy mergers and gas accretion from the cosmic web drive the growth of galaxies and their central black holes at early epochs. We report spectroscopic imaging of a multiple merger event in the most luminous known galaxy, WISE J224607.56?052634.9 (W2246?0526), a dust-obscured quasar at redshift 4.6, 1.3 Gyr after the Big Bang. Far-infrared dust continuum observations show three galaxy companions around W2246?0526 with disturbed morphologies, connected by streams of dust likely produced by the dynamical interaction. The detection of tidal dusty bridges shows that W2246?0526 is accreting its neighbors, suggesting merger activity is may be a dominant mechanism through which the most luminous galaxies simultaneously obscure and feed their central super-massive black holes.

化學Chemistry

Light-drivenfine chemical production in yeast biohybrids

光納米顆粒供能酵母菌製造高價值化學物質

作者：Junling Guo、Miguel Suástegui、Kelsey K. Sakimoto、Vanessa M. Moody、Gao Xiao，et al

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摘要：

一種新型可基因編程的酵母菌株能從簡單、可再生性碳來源生物製造高價值的化學物質；該酵母菌株的動力來自可採光的納米顆粒。

該半導體—微生物雜合體克服了生物無機系統的基本限制，為將來的生物混合體微生物設計奠定了基礎。

研究人員表示，這些微生物可高效性地適用於具更大複雜性和功能性的生物製造過程。

該研究建立了一種高度模塊化的基於發麵酵母（S. cerevisiae，麵包酵母）的生物無機混合平台。

除了能發麵和釀造啤酒，S. cerevisiae還被廣泛用於生物製造。

Abstract

Inorganic-biological hybrid systems have potential to be sustainable,efficient, and versatile chemical synthesis platforms by integrating thelight-harvesting properties of semiconductors with the synthetic potential ofbiological cells. We have developed a modular bioinorganic hybrid platform thatconsists of highly efficient light-harvesting indium phosphide nanoparticlesand genetically engineered Saccharomycescerevisiae, a workhorse microorganism in biomanufacturing. Theyeast harvests photogenerated electrons from the illuminated nanoparticles anduses them for the cytosolic regeneration of redox cofactors. This processenables the decoupling of biosynthesis and cofactor regeneration, facilitatinga carbon- and energy-efficient production of the metabolite shikimic acid, acommon precursor for several drugs and fine chemicals. Our work provides a platformfor the rational design of biohybrids for efficient biomanufacturing processeswith higher complexity and functionality.

Preventingchemical weapons as sciences converge

隨著科學融合防止化學武器

作者：Michael Crowley、Lijun Shang、Malcolm Dando

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摘要：

本文重點介紹了在一個科學發展快速變化及國家安全不確定的時期，國際組織面臨的某些新挑戰，並為確保持續禁止化學武器提供了重要的建議。

《禁止化學武器組織》（OPCW）在消除化學武器中取得的許多成功在很大程度上是因為CWC（這是由193個參與國簽署的國際條約，致力於全面禁止世界各地對化學武器的研發、生產和使用）。

研究人員表示，為了阻止化學武器的重新出現，某些科學問題必需得到解決並達成共識，例如就化學化合物或其輸送方法而言，與有毒化學物品及它們可能用於武器相關的風險連同近來的科學進展的定義正變得不夠明確。

Abstract

Stark illustrations of the dangers from chemicalweapons can be seen in attacks using toxic industrial chemicals and sarinagainst civilians and combatants in Syria and toxic industrial chemicals inIraq, as well as more targeted assassination operations in Malaysia and theUnited Kingdom, employing VX and novichok nerve agents, respectively. Concernsabout such malign applications of chemical technology are exacerbated by theunstable international security environment and the changing nature of armedconflict, 「where borderlines between war, civil war, large-scale violations ofhuman rights, revolutions and uprisings, insurgencies and terrorism as well asorganized crime are blurred」 (1). It is thus essential that the globalcommunity regularly review the nature and implications of developments inchemistry, and its convergence with the life and associated sciences, andestablish appropriate measures to prevent their misuse. With the parties to theChemical Weapons Convention (CWC) convening a Review Conference to address suchissues beginning 21 November 2018, we highlight important scientific aspects (2)

生物學Biology

In vivomodeling of human neuron dynamics and Down syndrome

人體神經元動力學和唐氏綜合征的活體建模

作者：Raquel Real、Manuel Peter、Antonio Trabalza、Shabana Khan，et al

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摘要：

利用人體幹細胞潛能模擬皮質迴路的生理機能和疾病，需要在活體內監測細胞動力學。

研究人員發現，移植到成年小鼠皮質的人誘導多能幹細胞衍生的皮質神經元能組織成大規模血管化神經膠質區域，並具有複雜的細胞結構。

在4個月的時間裡，人類突觸網路基本重組，突觸形成和消除的比率達到平衡。

該研究顯示了在人體組織移植中進行體內成像的潛力，可用於病人特定的皮質發育、生理和發病機制建模。

Abstract

Harnessing the potential of human stem cells formodeling the physiology and diseases of cortical circuitry requires monitoringcellular dynamics in vivo. We show that human induced pluripotent stem cell(iPSC)–derived cortical neurons transplanted into the adult mouse cortexconsistently organized into large (up to ~100 mm3) vascularized neuron-gliaterritories with complex cytoarchitecture. Longitudinal imaging of >4000grafted developing human neurons revealed that neuronal arbors refined viabranch-specific retraction; human synaptic networks substantially restructuredover 4 months, with balanced rates of synapse formation and elimination; andoscillatory population activity mirrored the patterns of fetal neural networks.Lastly, we found increased synaptic stability and reduced oscillations intransplants from two individuals with Down syndrome, demonstrating thepotential of in vivo imaging in human tissue grafts for patient-specificmodeling of cortical development, physiology, and pathogenesis.

Molecular,spatial, and functional single-cell profiling of the hypothalamic preopticregion

下丘腦視前區分子、空間和功能單細胞分析

作者：Jeffrey R. Moffitt、DhananjayBambah-Mukku、Stephen W. Eichhorn、Eric Vaugh，et al

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摘要：

下丘腦控制著基本社會行為和體內平衡功能。然而，人們對下丘腦核的細胞結構卻知之甚少。

在此，研究人員開發了一種基於圖像的原位細胞類型識別和映射方法，並將其與單細胞RNA測序相結合，創建了小鼠下丘腦視前區分子標記和空間解析的細胞圖譜。

研究分析了100萬個細胞，確定了約70個具有明顯神經調節特徵和空間組織的神經元群體，並識別了在雄性和雌性小鼠的社會行為中激活的特定神經元群體，為行為迴路的機械研究提供了一個高解析度框架。

Abstract

Thehypothalamus controls essential social behaviors and homeostatic functions.However, the cellular architecture of hypothalamic nuclei—including themolecular identity, spatial organization, and function of distinct celltypes—is poorly understood. Here, we developed an imaging-based in situcell-type identification and mapping method andcombined it with single-cell RNA-sequencing to create a molecularly annotatedand spatially resolved cell atlas of the mouse hypothalamic preoptic region. Weprofiled ~1 million cells, identified ~70 neuronal populations characterized bydistinct neuromodulatory signatures and spatial organizations, and definedspecific neuronal populations activated during social behaviors in male andfemale mice, providing a high-resolution framework for mechanisticinvestigation of behavior circuits. The approach described opens a new avenuefor the construction of cell atlases in diverse tissues and organisms.

Dietary fat:From foe to friend?

膳食脂肪：敵人還是朋友？

作者：David S. Ludwig、Walter C. Willett、Jeff S. Volek、Marian L. Neuhouser

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摘要：

飲食對人類健康有重大影響。

在本期《科學》特刊「飲食與健康」中，有4篇《綜述》探索了我們所吃的東西與健康間的關係，以及在這一領域中持續存在的各種爭議。

例如，幾十年來，飲食建議的前提是高脂肪攝入會導致肥胖、糖尿病、心臟病甚至癌症。

因此其中一篇關於膳食脂肪的論文，重點介紹了有關健康飲食中的油脂比例應該是多少的新的廣泛共識，以及頗具重要性的哪些特殊油脂可能最為健康。

研究人員它總結了現有的證據，以確定在關於宏量營養素和慢性疾病的爭論中存在廣泛共識的領域。

Abstract

For decades, dietary advice was based on the premise that high intakesof fat cause obesity, diabetes, heart disease, and possibly cancer. Recently,evidence for the adverse metabolic effects of processed carbohydrate has led toa resurgence in interest in lower-carbohydrate and ketogenic diets with highfat content. However, some argue that the relative quantity of dietary fat andcarbohydrate has little relevance to health and that focus should instead beplaced on which particular fat or carbohydrate sources are consumed. Thisreview, by nutrition scientists with widely varying perspectives, summarizesexisting evidence to identify areas of broad consensus amid ongoing controversyregarding macronutrients and chronic disease.

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