編譯|未玖
Science,31 JAN 2025, VOL 387, ISSUE 6733
《科學》2025年1月31日，第387卷，6733期
材料科學Materials Science
Transforming achiral semiconductors into chiral domains with exceptional circular dichroism
將非手性半導體轉化為具有特殊圓二色性的手性域
▲ 作者：THOMAS J. UGRAS, RIVER B. CARSON, REILLY P. LYNCH, HAOYANG LI, YUAN YAO, LORENZO CUPELLINI, ET AL.
▲鏈接：
https://www.science.org/doi/10.1126/science.ado7201
▲摘要：
硫化鎘、硒化鎘和碲化鎘的不對稱半導體幻數尺寸簇（MSCs）的高濃度溶液被引導通過受控干燥彎月面，從而形成手性MSC組件。這一過程使其躍遷偶極矩對齊，并產生了具有極強圓二色性的手性光學薄膜。
滴鑄膜的G因子高達1.30數量級，圖案化膜的G因子高達1.06數量級，接近理論極限。通過控制蒸發幾何形狀，研究組實現了不同形狀和尺寸的域，其中超過6平方毫米的同手性域可在左旋和右旋手性之間平滑過渡。
該研究結果揭示了彎月面沉積過程、超分子細絲及其MSC成分排列之間的基本關系，以及其與新興手性的關聯。
▲ 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
氧化鋁納米顆粒η-θ相變的非確定性動力學
▲ 作者：MASAYA SAKAKIBARA, MINORU HANAYA, TAKAYUKI NAKAMURO AND EIICHI NAKAMURA
▲鏈接：
https://www.science.org/doi/10.1126/science.adr8891
▲摘要：
相圖和晶體學是研究結構相變的標準工具，而在原子水平上獲取動力學信息被認為必不可少，但頗具挑戰性。氧化鋁的η-θ相變在塊體中是單向的，并保持了晶格取向。
研究組報道了一個統計動力學研究的罕見例子，表明對于塊體Al(OH)3表面上的納米顆粒，這種相變通過遍歷平衡態經熔融態非確定性地發生，并且晶格取向的記憶在此過程中丟失。結果發現，相互轉化率對電子劑量率不敏感，且該過程的吉布斯活化自由能較小。
這些非確定性動力學應該是在塊狀晶體高表面能區域發生晶體成核的一個關鍵特征。
▲ 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.
化學Chemistry
Conformational dynamics of a multienzyme complex in anaerobic carbon fixation
厭氧固碳中多酶復合物的構象動力學
▲ 作者：MAX DONGSHENG YIN, OLIVIER N. LEMAIRE, JOSé GUADALUPE ROSAS JIMéNEZ, MéLISSA BELHAMRI, ANNA SHEVCHENKO, GERHARD HUMMER, ET AL.
▲鏈接：
https://www.science.org/doi/10.1126/science.adr9672
▲摘要：
在古老的微生物Wood-Ljungdahl途徑中，二氧化碳（CO2）以多步驟過程固定，最終在雙功能一氧化碳脫氫酶/乙酰輔酶A合成酶復合物（CODH/ACS）上合成乙酰輔酶A （acetyl-CoA）。
研究組展示了氣體轉化產乙酸菌乙醇梭菌蛋白CODH/ACS的結構快照，表征了整個反應的分子編排，包括電子轉移到CODH進行CO2還原、從類咕啉鐵硫蛋白（CoFeSP）伴侶到ACS活性位點的甲基轉移，以及乙酰輔酶A的產生。
與CODH不同，多結構域ACS經歷了巨大的構象變化，形成了與CODH活性位點的內部連接，容納CoFeSP進行甲基轉移，并保護反應中間體。總而言之，這些結構使人們能夠繪制出這種酶的詳細反應機制，這對厭氧生物中CO2的固定至關重要。
▲ 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.
公共衛生Public Health
Pre-exposure antibody prophylaxis protects macaques from severe influenza
暴露前抗體預防性保護獼猴免受嚴重流感
▲ 作者：MASARU KANEKIYO, REBECCA A. GILLESPIE, KRISTINE COOPER, VANESSA GUERRA CANEDO, PRISCILA M. S. CASTANHA, AMARENDRA PEGU, ET AL.
▲鏈接：
https://www.science.org/doi/10.1126/science.ado6481
▲摘要：
流感病毒大流行和季節性流行病奪去了無數人的生命。具有大流行潛力的流感病毒反復發生人畜共患外溢，亟需采取有效對策。
在這項工作中，研究組發現廣泛中和抗體（bnAb） MEDI8852暴露前預防在保護食蟹猴免受高致病性禽流感H5N1氣溶膠病毒感染引起的重癥疾病方面非常有效。在試驗劑量下，保護作用是抗體劑量依賴性的，但獨立于Fc介導的效應器功能。
接受每公斤體重10毫克或更高劑量MEDI8852的獼猴在感染后的呼吸功能損害可以忽略不計，而對照動物卻未能免于重癥疾病和死亡。鑒于MEDI8852和其他bnAb的廣泛性，研究組希冀，不可預見的大流行性甲型流感病毒是可預防的。
▲ 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.
動物學Zoology
Tiger recovery amid people and poverty
老虎種群在群體和貧困中復蘇
▲ 作者：YADVENDRADEV V. JHALA, NINAD AVINASH MUNGI, RAJESH GOPAL AND QAMAR QURESHI
▲鏈接：
https://www.science.org/doi/10.1126/science.adk4827
▲摘要：
恢復大型但具有重要生態意義的食肉動物是一項艱巨的全球挑戰。印度是世界上人口最多的地區，老虎（孟加拉虎）的種群恢復為評估巨型動物恢復的社會生態驅動因素提供了一個獨特機會。
在過去的二十年里，老虎的棲息地增加了30%（每年2929平方千米），導致全球最大的老虎種群占地約138200平方千米。老虎一直占據著沒有人類、獵物豐富的保護區（35255平方千米），但也在與約6000萬人共享的鄰近連通棲息地定居。
老虎的消失和滅絕以武裝沖突、貧困和廣泛的土地利用變化為特征。只要社會經濟繁榮和政治穩定占據上風，為老虎預留生存空間就可以實現土地共享。印度虎群的恢復讓人們對巨型動物的恢復持審慎樂觀態度，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
古基因組學揭示家養綿羊的起源、傳播和發展
▲ 作者：KEVIN G. DALY, VICTORIA E. MULLIN, ANDREW J. HARE, áINE HALPIN, VALERIA MATTIANGELI, MATTHEW D. TEASDALE, ET AL.
▲鏈接：
https://www.science.org/doi/10.1126/science.adn2094
▲摘要：
家養綿羊（Ovis aries）的起源和史前演化尚未完全清楚；為了解決這個問題，研究組從歐亞大陸采樣的跨越12000年的118個古基因組中生成了數據。
公元前8000年左右，來自土耳其中部地區的基因組在遺傳學上接近綿羊的馴化起源，但不能完全解釋后來種群的祖先，這表明了野生祖先的鑲嵌融合。基因組特征表明，古代牧民對綿羊的毛色模式、有角性和生長速度進行了選擇。
盡管首批歐洲綿羊群起源于土耳其（與古代人類基因組的發現有顯著相似之處），但研究組在青銅時代發現了大量與西部草原相關的綿羊祖先。
▲ 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.
本文鏈接：《科學》（20250131出版）一周論文導讀http://www.lensthegame.com/show-11-16962-0.html
聲明：本網站為非營利性網站，本網頁內容由互聯網博主自發貢獻，不代表本站觀點，本站不承擔任何法律責任。天上不會到餡餅，請大家謹防詐騙！若有侵權等問題請及時與本網聯系，我們將在第一時間刪除處理。
上一篇： 一周熱聞回顧（2025年2月2日）
下一篇： 目標月球南極！嫦娥七號任務有哪些特殊之處