编译|未玖

Science,31 JAN 2025, VOL 387, ISSUE 6733

《科学》2025年1月31日，第387卷，6733期

材料科学Materials Science

Transforming achiral semiconductors into chiral domains with exceptional circular dichroism

将非手性半导体转化为具有特殊圆二色性的手性域

▲ 作者：THOMAS J. UGRAS, RIVER B. CARSON, REILLY P. LYNCH, HAOYANG LI, YUAN YAO, LORENZO CUPELLINI, ET AL.

▲链接：

https://www.science.org/doi/10.1126/science.ado7201

▲摘要：

硫化镉、硒化镉和碲化镉的不对称半导体幻数尺寸簇（MSCs）的高浓度溶液被引导通过受控干燥弯月面，从而形成手性MSC组件。这一过程使其跃迁偶极矩对齐，并产生了具有极强圆二色性的手性光学薄膜。

滴铸膜的G因子高达1.30数量级，图案化膜的G因子高达1.06数量级，接近理论极限。通过控制蒸发几何形状，研究组实现了不同形状和尺寸的域，其中超过6平方毫米的同手性域可在左旋和右旋手性之间平滑过渡。

该研究结果揭示了弯月面沉积过程、超分子细丝及其MSC成分排列之间的基本关系，以及其与新兴手性的关联。

▲ Abstract：

Highly concentrated solutions of asymmetric semiconductor magic-sized clusters (MSCs) of cadmium sulfide, cadmium selenide, and cadmium telluride were directed through a controlled drying meniscus front, resulting in the formation of chiral MSC assemblies. This process aligned their transition dipole moments and produced chiroptic films with exceptionally strong circular dichroism. G-factors reached magnitudes as high as 1.30 for drop-cast films and 1.06 for patterned films, approaching theoretical limits. By controlling the evaporation geometry, various domain shapes and sizes were achieved, with homochiral domains exceeding 6 square millimeters that transition smoothly between left- and right-handed chirality. Our results uncovered fundamental relationships between meniscus deposition processes, the alignment of supramolecular filaments and their MSC constituents, and their connection to emergent chiral properties.

Nondeterministic dynamics in the η-to-θ phase transition of alumina nanoparticles

氧化铝纳米颗粒η-θ相变的非确定性动力学

▲ 作者：MASAYA SAKAKIBARA, MINORU HANAYA, TAKAYUKI NAKAMURO AND EIICHI NAKAMURA

▲链接：

https://www.science.org/doi/10.1126/science.adr8891

▲摘要：

相图和晶体学是研究结构相变的标准工具，而在原子水平上获取动力学信息被认为必不可少，但颇具挑战性。氧化铝的η-θ相变在块体中是单向的，并保持了晶格取向。

研究组报道了一个统计动力学研究的罕见例子，表明对于块体Al(OH)₃表面上的纳米颗粒，这种相变通过遍历平衡态经熔融态非确定性地发生，并且晶格取向的记忆在此过程中丢失。结果发现，相互转化率对电子剂量率不敏感，且该过程的吉布斯活化自由能较小。

这些非确定性动力学应该是在块状晶体高表面能区域发生晶体成核的一个关键特征。

▲ Abstract：

Phase diagrams and crystallography are standard tools for studying structural phase transitions, whereas acquiring kinetic information at the atomistic level has been considered essential but challenging. The η-to-θ phase transition of alumina is unidirectional in bulk and retains the crystal lattice orientation. We report a rare example of a statistical kinetics study showing that for nanoparticles on a bulk Al(OH)₃ surface, this phase transition occurs nondeterministically through an ergodic equilibrium through the molten state, and the memory of the lattice orientation is lost in this process. The rate of the interconversion was found to be insensitive to the electron dose rate, and this process had a small Gibbs free energy of activation. These nondeterministic kinetics should be a key feature of crystal nucleation occurring in high-surface-energy regions of bulk crystals.

化学Chemistry

Conformational dynamics of a multienzyme complex in anaerobic carbon fixation

厌氧固碳中多酶复合物的构象动力学

▲ 作者：MAX DONGSHENG YIN, OLIVIER N. LEMAIRE, JOSé GUADALUPE ROSAS JIMéNEZ, MéLISSA BELHAMRI, ANNA SHEVCHENKO, GERHARD HUMMER, ET AL.

▲链接：

https://www.science.org/doi/10.1126/science.adr9672

▲摘要：

在古老的微生物Wood-Ljungdahl途径中，二氧化碳（CO₂）以多步骤过程固定，最终在双功能一氧化碳脱氢酶/乙酰辅酶A合成酶复合物（CODH/ACS）上合成乙酰辅酶A （acetyl-CoA）。

研究组展示了气体转化产乙酸菌乙醇梭菌蛋白CODH/ACS的结构快照，表征了整个反应的分子编排，包括电子转移到CODH进行CO₂还原、从类咕啉铁硫蛋白（CoFeSP）伴侣到ACS活性位点的甲基转移，以及乙酰辅酶A的产生。

与CODH不同，多结构域ACS经历了巨大的构象变化，形成了与CODH活性位点的内部连接，容纳CoFeSP进行甲基转移，并保护反应中间体。总而言之，这些结构使人们能够绘制出这种酶的详细反应机制，这对厌氧生物中CO₂的固定至关重要。

▲ Abstract：

In the ancient microbial Wood-Ljungdahl pathway, carbon dioxide (CO₂) is fixed in a multistep process that ends with acetyl–coenzyme A (acetyl-CoA) synthesis at the bifunctional carbon monoxide dehydrogenase/acetyl-CoA synthase complex (CODH/ACS). In this work, we present structural snapshots of the CODH/ACS from the gas-converting acetogen Clostridium autoethanogenum, characterizing the molecular choreography of the overall reaction, including electron transfer to the CODH for CO₂ reduction, methyl transfer from the corrinoid iron-sulfur protein (CoFeSP) partner to the ACS active site, and acetyl-CoA production. Unlike CODH, the multidomain ACS undergoes large conformational changes to form an internal connection to the CODH active site, accommodate the CoFeSP for methyl transfer, and protect the reaction intermediates. Altogether, the structures allow us to draw a detailed reaction mechanism of this enzyme, which is crucial for CO₂ fixation in anaerobic organisms.

公共卫生Public Health

Pre-exposure antibody prophylaxis protects macaques from severe influenza

暴露前抗体预防性保护猕猴免受严重流感

▲ 作者：MASARU KANEKIYO, REBECCA A. GILLESPIE, KRISTINE COOPER, VANESSA GUERRA CANEDO, PRISCILA M. S. CASTANHA, AMARENDRA PEGU, ET AL.

▲链接：

https://www.science.org/doi/10.1126/science.ado6481

▲摘要：

流感病毒大流行和季节性流行病夺去了无数人的生命。具有大流行潜力的流感病毒反复发生人畜共患外溢，亟需采取有效对策。

在这项工作中，研究组发现广泛中和抗体（bnAb） MEDI8852暴露前预防在保护食蟹猴免受高致病性禽流感H5N1气溶胶病毒感染引起的重症疾病方面非常有效。在试验剂量下，保护作用是抗体剂量依赖性的，但独立于Fc介导的效应器功能。

接受每公斤体重10毫克或更高剂量MEDI8852的猕猴在感染后的呼吸功能损害可以忽略不计，而对照动物却未能免于重症疾病和死亡。鉴于MEDI8852和其他bnAb的广泛性，研究组希冀，不可预见的大流行性甲型流感病毒是可预防的。

▲ Abstract：

Influenza virus pandemics and seasonal epidemics have claimed countless lives. Recurrent zoonotic spillovers of influenza viruses with pandemic potential underscore the need for effective countermeasures. In this study, we show that pre-exposure prophylaxis with broadly neutralizing antibody (bnAb) MEDI8852 is highly effective in protecting cynomolgus macaques from severe disease caused by aerosolized highly pathogenic avian influenza H5N1 virus infection. Protection was antibody dose–dependent yet independent of Fc-mediated effector functions at the dose tested. Macaques receiving MEDI8852 at 10 milligrams per kilogram or higher had negligible impairment of respiratory function after infection, whereas control animals were not protected from severe disease and fatality. Given the breadth of MEDI8852 and other bnAbs, we anticipate that protection from unforeseen pandemic influenza A viruses is achievable.

动物学Zoology

Tiger recovery amid people and poverty

老虎种群在群体和贫困中复苏

▲ 作者：YADVENDRADEV V. JHALA, NINAD AVINASH MUNGI, RAJESH GOPAL AND QAMAR QURESHI

▲链接：

https://www.science.org/doi/10.1126/science.adk4827

▲摘要：

恢复大型但具有重要生态意义的食肉动物是一项艰巨的全球挑战。印度是世界上人口最多的地区，老虎（孟加拉虎）的种群恢复为评估巨型动物恢复的社会生态驱动因素提供了一个独特机会。

在过去的二十年里，老虎的栖息地增加了30%（每年2929平方千米），导致全球最大的老虎种群占地约138200平方千米。老虎一直占据着没有人类、猎物丰富的保护区（35255平方千米），但也在与约6000万人共享的邻近连通栖息地定居。

老虎的消失和灭绝以武装冲突、贫困和广泛的土地利用变化为特征。只要社会经济繁荣和政治稳定占据上风，为老虎预留生存空间就可以实现土地共享。印度虎群的恢复让人们对巨型动物的恢复持审慎乐观态度，尤其是在南半球。

▲ Abstract：

Recovery of large yet ecologically important carnivores poses a formidable global challenge. Tiger (Panthera tigris) recovery in India, the world’s most populated region, offers a distinct opportunity to evaluate the socio-ecological drivers of megafauna recovery. Tiger occupancy increased by 30% (at 2929 square kilometers per year) over the past two decades, leading to the largest global population occupying ~138,200 square kilometers. Tigers persistently occupied human-free, prey-rich protected areas (35,255 square kilometers) but also colonized proximal connected habitats that were shared with ~60 million people. Tiger absence and extinction were characterized by armed conflict, poverty, and extensive land-use changes. Sparing land for tigers enabled land sharing, provided that socioeconomic prosperity and political stability prevailed. India’s tiger recovery offers cautious optimism for megafauna recovery, particularly in the Global South.

Ancient genomics and the origin, dispersal, and development of domestic sheep

古基因组学揭示家养绵羊的起源、传播和发展

▲ 作者：KEVIN G. DALY, VICTORIA E. MULLIN, ANDREW J. HARE, áINE HALPIN, VALERIA MATTIANGELI, MATTHEW D. TEASDALE, ET AL.

▲链接：

https://www.science.org/doi/10.1126/science.adn2094

▲摘要：

家养绵羊（Ovis aries）的起源和史前演化尚未完全清楚；为了解决这个问题，研究组从欧亚大陆采样的跨越12000年的118个古基因组中生成了数据。

公元前8000年左右，来自土耳其中部地区的基因组在遗传学上接近绵羊的驯化起源，但不能完全解释后来种群的祖先，这表明了野生祖先的镶嵌融合。基因组特征表明，古代牧民对绵羊的毛色模式、有角性和生长速度进行了选择。

尽管首批欧洲绵羊群起源于土耳其（与古代人类基因组的发现有显著相似之处），但研究组在青铜时代发现了大量与西部草原相关的绵羊祖先。

▲ Abstract：

The origins and prehistory of domestic sheep (Ovis aries) are incompletely understood; to address this, we generated data from 118 ancient genomes spanning 12,000 years sampled from across Eurasia. Genomes from Central Türkiye ~8000 BCE are genetically proximal to the domestic origins of sheep but do not fully explain the ancestry of later populations, suggesting a mosaic of wild ancestries. Genomic signatures indicate selection by ancient herders for pigmentation patterns, hornedness, and growth rate. Although the first European sheep flocks derive from Türkiye, in a notable parallel with ancient human genome discoveries, we detected a major influx of Western steppe–related ancestry in the Bronze Age.