Science,22 May 2025,Volume 388, Issue 6749
《科學》2025年5月22日，第388卷，6749期
物理學 Physics
A pulsar-helium star compact binary system formed by common envelope evolution
由共同包層演化形成的脈沖星-氦星致密雙星系統
▲ 作者：Z. L. YANG, J. L. HAN, D. J. ZHOU, W. C. JING, W. C. CHEN, T. WANG, X. D. LI, S. WANG, B. WANG , AND C. F. ZHANG
▲鏈接：
https://www.science.org/doi/10.1126/science.ado0769
▲摘要：雙星系統中的恒星可以相互作用，從而影響兩個天體的演化。理論預測，一些雙星系統經歷了一個共同的包絡階段，其中一個天體在其伴星的外層內運行，但這還沒有被直接觀察到。研究者發現了一顆快速旋轉的脈沖星，它與一顆伴星氦恒星在近軌道上運行。
與理論模型的比較表明，該系統最近經歷了一個共同的包絡階段，脈沖星在主序伴星的包絡內運行。伴星的外殼在一千年內被拋出，形成了氦星，一些質量被轉移到脈沖星上，增加了它的自旋速率。
▲ Abstract：Stars in binary systems can interact, which affects the evolution of both objects. Theory predicts that some binary systems experience a common envelope phase in which one object orbits within the outer layers of its companion, but this has not been directly observed. Yang et al. identified a rapidly spinning pulsar on a close orbit with a companion helium star. Comparison with theoretical models showed that this system recently underwent a common envelope phase, with the pulsar orbiting inside the envelope of a main sequence companion. The companion’s envelope was ejected within a thousand years, producing the helium star, and some mass was transferred to the pulsar, increasing its spin rate.
Erasure cooling, control, and hyperentanglement of motion in optical tweezers
光鑷中原子運動態的量子操控與超糾纏冷卻新機制
▲ 作者：ADAM L. SHAW, PASCAL SCHOLL, RAN FINKELSTEIN, RICHARD BING-SHIUN TSAI, JOONHEE CHOI, AND MANUEL ENDRES
▲鏈接：
https://www.science.org/doi/10.1126/science.adn2618
▲摘要：被困在光鑷中的原子是一個很有前途的量子信息處理平臺。通常在這樣的系統中，量子信息被編碼在原子的電子或核狀態中。然而，它們的運動狀態對環境影響更強，也可以用于量子信息。
研究者用一組充滿鍶原子的光學鑷子演示了這種方法。他們首先以高保真度將原子冷卻到運動基態，然后繼續在運動和電子自由度上創造貝爾狀態，這被稱為超糾纏。
▲ Abstract：Atoms trapped in optical tweezers are a promising platform for quantum information processing. Typically in such systems, quantum information is encoded in the atoms’ electronic or nuclear states. However, their motional states, which are more robust to environmental effects, could also be exploited for quantum information. Shaw et al. have demonstrated this approach using an array of optical tweezers filled with strontium atoms. The researchers first cooled the atoms to their motional ground state with high fidelity and then went on create a Bell state in both motional and electronic degrees of freedom, which is known as hyperentanglement.
生物學 Biology
The emergence and demise of giant sloths
巨型樹懶的出現和消亡
▲ 作者：ALBERTO BOSCAINI, DANIEL M. CASALI, NéSTOR TOLEDO, JUAN L. CANTALAPIEDRA, M. SUSANA BARGO, GERARDO DE IULIIS, TIMOTHY J. GAUDIN, MAX C. LANGER, RACHEL NARDUCCI, AND IGNACIO M. SOTO
▲鏈接：
https://www.science.org/doi/10.1126/science.adu0704
▲摘要：現今，有六種樹懶，它們都有類似的生態環境，比如樹棲和緩慢的新陳代謝。這些物種是一個曾經多樣化的美洲分支的一小部分殘余，這個分支主要由大型物種組成。作者研究了樹懶的進化史，揭示了樹懶的祖先群體是陸生的和大型的，較小的物種被衍生出來并聚集在一起。
在3000萬年的時間里，樹懶家族在美洲各地多樣化，從一個像大象一樣大的物種演化成一個完全水生的物種。不幸的是，像大多數其他大型更新世食草動物一樣，這個進化支幾乎被新到達的人類完全消滅了。
▲ Abstract：Today, there are six species of sloths, all of which have similar ecologies such as arboreality and a slow metabolism. These species are a tiny remnant of a once diverse American clade that was mostly made up of large-bodied species. Boscaini et al. looked across the evolutionary history of sloths and reveal that the ancestral groups were terrestrial and large, with smaller species being derived and convergent. For 30 million years, the sloth family diversified across the Americas, from a species as large as an elephant to one that was entirely aquatic. Unfortunately, like most other large Pleistocene herbivores, the clade was almost entirely eradicated by newly arriving humans.
Deep learning–guided design of dynamic proteins
基于深度學習的動態蛋白質設計
▲ 作者：AMY B. GUO, DENIZ AKPINAROGLU, CHRISTINA A. STEPHENS, MICHAEL GRABE, COLIN A. SMITH, MARK J. S. KELLY, AND TANJA KORTEMME
▲鏈接：
https://www.science.org/doi/10.1126/science.adr7094
▲摘要：許多信號蛋白和酶會對小分子或離子的結合作出反應，通過改變動力學傾向于一種結構構象而不是另一種結構構象。這種行為是生物功能的關鍵。但在設計的蛋白質中設定出這些特性是非常具有挑戰性的。研究者開發了一種算法來設計這種可以感知并響應鈣離子結合的動態蛋白質。
從結合鈣離子的靜態蛋白質開始，研究者確定了潛在的替代構象，并使用AlphaFold2預測來識別與兩種結構兼容的序列。分子動力學模擬和核磁共振實驗驗證了一種動態的多態設計，可以在離子結合時轉變為單一構象。
▲ Abstract：Many signaling proteins and enzymes respond to binding of a small molecule or ion by shifting dynamics to favor one structural conformation over another. This behavior is key to biological function, but engineering these properties in designed proteins is very challenging. Guo et al. developed a computational approach to designing such dynamic proteins that can sense and respond to binding of a calcium ion. Starting with a static protein that binds a calcium ion, the authors identified potential alternate conformations and used AlphaFold2 predictions to identify sequences that were compatible with both structures. Validation with molecular dynamics simulations and nuclear magnetic resonance experiments confirmed a dynamic, multistate design that could be shifted into a single conformation upon ion binding.
生態學 Ecology
Functional biogeography of marine microbial heterotrophs
海洋微生物異養生物的功能生物地理學
▲ 作者：EMILY J. ZAKEM, JESSE MCNICHOL, J. L. WEISSMAN, YUBIN RAUT, LIANG XU, ELISA R. HALEWOOD, CRAIG A. CARLSON, STEPHANIE DUTKIEWICZ, JED A. FUHRMAN, AND NAOMI M. LEVINE
▲鏈接：
https://www.science.org/doi/10.1126/science.ado5323
▲摘要：在海洋中，碳循環主要由微生物光合作用和呼吸作用驅動。有幾種方法將碳以不穩定和頑固性的溶解有機碳形式封存在深處。研究者認識到，目前微生物動力學在海洋碳儲存中的作用的生物地球化學模型是不充分的。
為了改進模型，他們利用來自太平洋、大西洋和印度洋樣帶的可用數據集來調查海洋微生物群落的結構，然后研究這種結構與功能的關系。在低緯度地區，可以看出垂直梯度——在表層有寡養生物，而在中上層深處有越來越多的共養生物，它們避免被表層捕食，生長緩慢，是調節海洋中溶解碳儲量的關鍵。
▲ Abstract：In the ocean, the carbon cycle is driven mainly by microbial photosynthesis and respiration. Several processes sequester carbon at depth in labile and recalcitrant forms of dissolved organic carbon. Zakem et al. recognized that current biogeochemical models for the roles of microbial dynamics in ocean carbon storage are inadequate. To improve models, the authors harnessed available datasets from Pacific, Atlantic, and Indian Ocean transects to investigate the structure of oceanic microbial communities and then studied how this structure relates to function. At low latitudes, a vertical gradient can be discerned, with oligotrophs on the surface and increasingly copiotrophic populations at mesopelagic depths that avoid surface predation, grow slowly, and are key to regulating the amount of dissolved carbon stored in the ocean.
化學 Chemistry
Turf algae redefine the chemical landscape of temperate reefs, limiting kelp forest recoveryl
草皮藻類重新定義溫帶珊瑚礁的化學景觀
▲ 作者：SHANE P. FARRELL, DANIEL PETRAS, PAOLO STINCONE, DARA S. YIU, JOHN A. BURNS, ABZER KELMINAL PAKKIR SHAH, AARON C. HARTMANN, DAMIAN C. BRADY, AND DOUGLAS B. RASHER
▲鏈接：
https://www.science.org/doi/10.1126/science.adt6788
▲摘要：在經歷海洋快速變暖的溫帶地區，海帶森林正在被化學成分豐富的草皮藻類所取代。然而，這些草皮藻類在多大程度上改變了周圍的化學環境或影響海帶森林的反彈潛力仍然未知。
研究者使用水下視覺調查、綜合化學分析和實驗室實驗來揭示草皮藻類向水中釋放生物活性化合物，從根本上改變了珊瑚礁的“化學景觀”，并直接抑制了海帶的形成。
研究表明，化學生態學在塑造現代海帶森林生態系統及其恢復能力方面至關重要。此外，該研究表明扭轉氣候驅動的國家轉變不僅需要遏制全球碳排放，還需要實施有針對性的地方干預措施，打破有害的生態反饋循環，促進恢復。
▲ Abstract：In temperate regions experiencing rapid ocean warming, kelp forests are being replaced by chemically rich turf algae. However, the extent to which these turf algae alter the surrounding chemical environment or affect the rebound potential of kelp forests (through chemically mediated interactions) remains unknown. Here, we used underwater visual surveys, comprehensive chemical profiling, and laboratory experiments to reveal that turf algae release bioactive compounds into the water that fundamentally alter the reef “chemical landscape” and directly suppress kelp recruitment. Therefore, our study reveals that chemical ecology is critical in shaping modern kelp forest ecosystems and their resilience. Further, it demonstrates that reversing climate-driven state shifts will require not only curbing global carbon emissions but also implementing targeted local interventions that break harmful ecological feedback loops and foster recovery.
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