编译 | 唐一尘
Science, 01 NOVEMBER 2019, VOL 366, ISSUE 6465
《科学》2019年11月1日，第366卷，6465期
动物/环境科学
Zoology/Environmental Science
Genomic architecture and introgression shape a butterfly radiation基因组结构和基因渗入形成了蝴蝶多样性
作者：Nathaniel B. Edelman、Paul B. Frandsen、Michael Miyagi，et al.
链接：
https://science.sciencemag.org/content/366/6465/594
摘要：
适应性辐射是扩大生物多样性的驱动力。填补新生态位或对变化的环境做出反应的需求可能会引起属内的快速多样化，从而导致众多具独特适应性的新物种。
然而，杂交在演化中的重要性一直是演化生物学中一个备受争议的话题。袖蝶属是由至少40个蝴蝶品种组成的多样化属，它们以其多彩且极为独特的翅翼图案而闻名。
由于这种多样性，该物种一直被用于研究物种之间的基因渗入。然而，由于难以区分基因混合，杂交在袖蝶属适应性辐射中的作用仍然受到质疑。
这里，研究人员制备了20个新的基因组装配体，并使用一种新方法确认通过杂交引入的基因变异。
结果显示，通过多个独立的基因渗入事件所引入的基因变异极大地影响了袖蝶的演化历史，而基因渗入的影响会随局部重组、基因密度和基因组架构而异。
这些结果提示，物种间偶尔的基因渗入和重组可能会对基因组产生重大的长期影响，并为物种的快速适应性分化和辐射提供必要的基因物质。
Abstract
We used 20 de novo genome assemblies to probe the speciation history and architecture of gene flow in rapidly radiating Heliconiusbutterflies. Our tests to distinguish incomplete lineage sorting from introgression indicate that gene flow has obscured several ancient phylogenetic relationships in this group over large swathes of the genome. Introgressed lociare underrepresented in low-recombination and gene-rich regions, consistent with the purging of foreign alleles more tightly linked to incompatibility loci. Here, we identify a hitherto unknown inversion that traps a color pattern switch locus. We infer that this inversion was transferred between lineages by introgression and is convergent with a similar rearrangement in another part ofthe genus. These multiple de novo genome sequences enable improved understanding of the importance of introgression and selective processes inadaptive radiation.
Neonicotinoids disrupt aquatic food webs and decrease fishery yields烟碱类杀虫剂破坏了水生食物网并降低渔业产量
作者：Masumi Yamamuro、Takashi Komuro、Hiroshi Kamiya，et al.
链接：
https://science.sciencemag.org/content/366/6465/620
摘要：
无脊椎动物的减少在陆地生态系统中非常普遍，而农药的使用也常常被认为是一个原因。
在此，研究人员报告了水生系统受到烟碱类杀虫剂的高毒性和持久性的威胁。这些效应通过改变食物网的结构和动态，影响到更高的营养水平和更高层次的消费者。
通过分析浮游动物、水质、鳗鱼和胡瓜鱼的年度渔业产量，研究人员发现，在日本岛根县烟碱类杀虫剂应用的流域，自1993年以来，在春季，平均浮游动物生物量减少83%，导致渔业产量从240吨暴跌到到22吨。
研究人员表示，这种干扰也可能发生在其他地方，因为烟碱类杀虫剂是目前全球使用最广泛的一类杀虫剂。
Abstract
Invertebrate declines are widespread in terrestrial ecosystems, and pesticide use is often cited as a causal factor. Here, we report that aquatic systems are threatened by the high toxicity and persistence of neonicotinoid insecticides. These effects cascade to higher trophic levels by altering food web structure and dynamics, affecting higher-level consumers. Using data on zooplankton, water quality, and annual fishery yields of eel and smelt, we show that neonicotinoid application to watersheds since 1993 coincided with an 83% decrease in average zooplankton biomass in spring, causing the smelt harvest to collapse from 240 to 22 tons in Lake Shinji, Shimane Prefecture, Japan. This disruption likely also occurs elsewhere, as neonicotinoids are currently the most widely used class of insecticides globally.
免疫学及生物医学工程
Immunity and Biomedical Engineering
Architecture of African swine fever virus and implications for viral assembly非洲猪瘟病毒结构及组装机制
作者：Nan Wang、Zhigao Bu、Zihe Rao、Xiangxi Wang，et al.
链接：
https://science.sciencemag.org/content/366/6465/640
摘要：
非洲猪瘟病毒约100年前首次被人类发现，至今已经从非洲传播至欧洲、南美洲、亚洲等地多个国家。
该病毒引起非洲猪瘟，能感染各品种和年龄的猪，发病率和死亡率极高。自2018年我国通报首例非洲猪瘟疫情以来，非洲猪瘟病毒呈现较快的传播速度。
这里，研究人员成功分离出国内非洲猪瘟病毒流行株，并首次解析了该病毒颗粒的三维结构，为开发新型非洲猪瘟疫苗奠定了基础。
结果显示，非洲猪瘟病毒是一种相当巨大、复杂的病原体。同时，研究人员新鉴定出非洲猪瘟病毒多种结构蛋白，提出其可能的组装机制，为揭示该病毒入侵宿主细胞以及逃避和对抗宿主抗病毒免疫的机制提供了重要线索。
Abstract
African swine fever virus (ASFV) is a giant and complex DNA virus that causes a highly contagious and often lethal swine disease for which no vaccine is available. Using an optimized image reconstruction strategy, we solved the ASFV capsid structure up to 4.1 angstroms, which is built from 17,280 proteins, including one major (p72) and four minor (M1249L, p17, p49, and H240R) capsid proteins organized into pentasymmetrons and trisymmetrons. The atomic structure of the p72 protein informs putative conformational epitopes, distinguishing ASFV from other nucleocytoplasmic large DNA viruses. The minor capsid proteins form a complicated network below the outer capsid shell, stabilizing the capsid by holding adjacent capsomers together. Acting as core organizers, 100-nanometer-long M1249L proteins run along each edge of the trisymmetrons that bridge two neighboring pentasymmetrons and form extensive intermolecular networks with other capsidproteins, driving the formation of the capsid framework. These structural details unveil the basis of capsid stability and assembly, opening up newavenues for African swine fever vaccine development.
Measles virus infection diminishes preexisting antibodies that offer protection from other pathogens麻疹病毒感染会减少预先存在的抗体，而这些抗体可以保护机体免受其他病原体的侵害作者：Michael J. Mina、Tomasz Kula、Yumei Leng，et al.
链接：
https://science.sciencemag.org/content/366/6465/599
摘要：
针对77名未接种疫苗儿童在麻疹感染前后免疫系统的研究揭示，这种感染可长期削弱对病毒和细菌的免疫力，从而产生一种免疫失忆，使这些人将来更容易受到其他病原体的感染 。
这里，研究人员使用了一种名为VirScan的工具分析未接种疫苗的儿童在麻疹感染前后的抗体（即针对并抵御异物—包括病毒抗原—的蛋白）反应。
该技术可对血液中数千种针对病毒和微生物抗原的抗体进行追踪。
研究人员发现，在感染麻疹两个月后，该病毒消耗了每个人的11％至73％的抗体储备，即使在疾病康复后，针对各种传染性病原体的免疫记忆也严重受损。但在接种了麻疹、腮腺炎和风疹疫苗的婴儿中则未见抗体耗竭。
此外，在感染麻疹的猕猴中，60％的抗体储备在至少5个月中都无法被检测到。研究人员表示，这突出了广泛接种疫苗的必要性。
Abstract
Measles virus is directly responsible for more than 100,000 deaths yearly. Epidemiological studies have associated measles with increased morbidity and mortality for years after infection, but the reasons why are poorly understood. Measles virus infects immune cells, causing acuteimmune suppression. To identify and quantify long-term effects of measles on the immune system, we used VirS can, an assay that tracks antibodies to thousands of pathogen epitopes in blood. We studied 77 unvaccinated children before and 2 months after natural measles virus infection. Measles cause delimination of 11 to 73% of the antibody repertoire across individuals. Recovery of antibodies was detected after natural reexposure to pathogens. Notably, these immune system effects were not observed in infants vaccinated against MMR (measles, mumps, and rubella), but were confirmed in measles-infected macaques.The reduction in humoral immune memory after measles infection generates potential vulnerability to future infections, underscoring the need for widespread vaccination.
Coupled electrophysiological, hemodynamic, and cerebrospinal fluid oscillations in human sleep人类睡眠中的电生理、血液动力学和脑脊液振荡
作者：Nina E. Fultz、Giorgio Bonmassar、Kawin Setsompop，et al.
链接：
https://science.sciencemag.org/content/366/6465/628
摘要：
睡眠对脑健康至关重要。已知非快速眼动睡眠的慢波神经元活动可支持记忆处理和巩固以及大脑的生理维持。
在该睡眠过程中，组织间液容积和流动对脑的盥洗增加，冲掉了积聚的可能导致神经变性的有毒废物蛋白。
然而，为什么这两个看似无关的过程会同时发生，或者它们是否甚至是关联的则仍然无法解释。
这里，研究人员使用加速神经成像技术检测了睡眠中人脑的生理和神经活动，揭示了在非快速眼动睡眠期间存在于电生理、血液和脑脊液动力学之间的关系模式。
结果显示，在神经元慢波之后跟随出现的是脑中血容量和血流的振荡，从而为耦合的脑脊液波流入和流出脑腔创造了空间。研究人员证明，神经元慢波不仅对记忆重要，还能改变脑的生理和流体动力学。
由于慢波睡眠中断和脑中毒性代谢蛋白的积累与包括阿尔茨海默氏病在内的数种疾病有关，因此这些结果可能有助于改善疾病影响。
Abstract
Sleep is essential for both cognition and maintenance of healthy brain function. Slow waves in neural activity contribute to memory consolidation, whereas cerebrospinal fluid (CSF) clears metabolic waste products from the brain. Whether these two processes are related is not known. We used accelerated neuroimaging to measure physiological and neural dynamicsin the human brain. We discovered a coherent pattern of oscillating electrophysiological, hemodynamic, and CSF dynamics that appears duringnon–rapid eye movement sleep. Neural slow waves are followed by hemodynamic oscillations, which in turn are coupled to CSF flow. These results demonstrate that the sleeping brain exhibits waves of CSF flow on a macroscopic scale, and these CSF dynamics are interlinked with neural and hemodynamic rhythms.
天文学Astronomy
A unified mechanism for unconfined deflagration-to-detonation transition in terrestrial chemical systems and typeI a supernovae超新星爆燃—爆轰转换的统一机制
作者：Alexei Y. Poludnenko、Jessica Chambers、Kareem Ahmed，et al.
链接：
https://science.sciencemag.org/content/366/6465/eaau7365
摘要：
Ia型超新星（SNIa）——白矮星的热核爆炸——的性质是天体物理学中一个悬而未决的问题。
几乎所有现有的正常、明亮SNIa的理论模型都要求爆发产生爆轰，以消耗所有的恒星物质，但爆发到爆轰转变（DDT）的机制仍不清楚。
本研究提出了湍流诱导的DDT的统一理论，描述了在无约束化学爆炸和热核爆炸中起爆的机理和条件。
通过化学火焰实验和热核火焰数值模拟，验证了模型的正确性。在SNIa模型中，研究人员使用所发展的理论确定了起爆标准，并表明在密度为每立方厘米107至108克时，DDT几乎是不可避免的。
Abstract
The nature of type Ia supernovae (SNIa)—thermonuclear explosions of white dwarf stars—is an open question in astrophysics. Virtually all existing theoretical models of normal, bright SNIa require the explosion to produce a detonation in order to consume all of stellar material, but themechanism for the deflagration-to-detonation transition (DDT) remains unclear. We present a unified theory of turbulence-induced DDT that describes the mechanism and conditions for initiating detonation both in unconfined chemical and thermonuclear explosions. The model is validated by using experiments with chemical flames and numerical simulations of thermonuclear flames. We use the developed theory to determine criteria for detonation initiation in the single-degenerate Chandrasekhar-mass SNIa model and show that DDT is almost inevitableat densities of 107 to 108 gramsper cubic centimeter.
A noninteracting low-massblack hole–giant star binary system一个相互作用的低质量黑洞—巨星双星系统
作者：Todd A. Thompson、Christopher S. Kochanek、Krzysztof Z. Stanek，et al.
链接：
https://science.sciencemag.org/content/366/6465/637
摘要：
带有伴星的黑洞双星系统通常是通过相互作用和吸积产生的x射线辐射发现的。而不相互作用的双星预计在银河系中会大量存在，但必须用其他方法进行观测。
本研究将径向速度和光度变化数据结合起来，表明这颗明亮、快速旋转的巨星2MASS J05215658+4359220是在一个有着巨大的看不见的伴星的双星系统中。该系统的轨道周期约为83天，偏心距接近于零。
这颗巨星的光度变化周期与轨道周期一致，而对这颗巨星的质量和半径的限制意味着，这颗看不见的伴星的质量是
倍太阳质量，这表明它是一个没有相互作用的低质量黑洞，或者是一颗质量大得出乎意料的中子星。
Abstract
Black hole binary systems with companion stars are typically found via their x-ray emission, generated by interaction and accretion. Noninteracting binaries are expected to be plentiful in the Galaxy but must be observed using other methods. We combine radialvelocity and photometric variability data to show that the bright, rapidly rotating giant star 2MASS J05215658+4359220 is in a binary system with amassive unseen companion. The system has an orbital period of ~83 days and near-zero eccentricity. The photometric variability period of the giant is consistent with the orbital period, indicating star spots and tidal synchronization. Constraints on the giant’s mass and radius imply that the unseen companion is
solar masses, indicating that it is anoninteracting low-mass black hole or an unexpectedly massive neutron star.
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