編譯|李言
Nature,17 July 2025,Volume 643 Issue 8072
《自然》，2025年7月17日，第643卷，8072期
天文學Astronomy
Close-in planet induces flares on its host star
近距離行星在主星上引起耀斑
▲ 作者：Ekaterina Ilin, Harish K. Vedantham et al.
▲鏈接：
https://www.nature.com/articles/s41586-025-09236-z
▲摘要：
該研究報道了擁有兩顆已知近軌行星的1700萬年的G型矮星在HIP 67522恒星上探測到的行星誘發耀斑現象。
通過結合凌日系外行星巡天衛星的太空光度測量數據及特征化系外行星望遠鏡歷時5年的專項觀測，發現該恒星的15次耀斑爆發最內層行星凌日相位附近集中出現，表明該系統中存在持續的磁星—行星相互作用。這種相互作用的穩定性意味著，最內層行星持續承受著比沒有相互作用時高出六倍的耀斑速率。
隨后，高能輻射與粒子流持續轟擊HIP 67522 b行星，這可能解釋了詹姆斯·韋伯太空望遠鏡近期探測到的該行星大氣層的異常膨脹。因此，HIP 67522系統堪稱研究磁星—行星相互作用對新生系外行星大氣影響的典型范例。
▲ Abstract：
Here we report the detection of planet-induced flares on HIP 67522, a 17 million-year-old G dwarf star with two known close-in planets. Combining space-borne photometry from the Transiting Exoplanet Survey Satellite and dedicated Characterising Exoplanets Telescope observations over 5?years, we find that the 15 flares in HIP 67522 cluster near the transit phase of the innermost planet, indicating persistent magnetic star–planet interaction in the system. The stability of interaction implies that the innermost planet is continuously self-inflicting a six times higher flare rate than it would experience without interaction. The subsequent flux of energetic radiation and particles bombarding HIP 67522 b may explain the remarkably extended atmosphere of the planet, recently detected with the James Webb Space Telescope. HIP 67522 is, therefore, an archetype to understand the impact of magnetic star–planet interaction on the atmospheres of nascent exoplanets.
Refractory solid condensation detected in an embedded protoplanetary disk
在原行星盤內部探測到難熔固態物質凝結
▲ 作者：M. K. McClure, Merel van’t Hoff et al.
▲鏈接：
https://www.nature.com/articles/s41586-025-09163-z
▲摘要：
研究首次觀測到行星系統誕生的'零時刻'，捕捉到一個新生行星系統誕生的初始狀態。
通過詹姆斯·韋伯太空望遠鏡和阿塔卡馬大型毫米波陣列對年輕原恒星HOPS-315進行紅外與毫米波聯合觀測，研究發現其2.2天文單位內的星盤大氣層底部存在溫暖的氧化硅氣體與結晶硅酸鹽礦物儲層，該區域與毫米波觀測到的氧化硅噴流在空間上完全隔離。
通過與快速顆粒生長凝結模型及星盤結構模型的對比，表明此處形成的難熔固態物質與太陽系內同類物質具有相似性。研究結果表明，星盤內緣區域的物質環境受到星際固態物質升華作用支配，隨后從該氣體儲層中再凝結形成的難熔固體物質，其時間尺度與太陽系內難熔物質凝結過程相當。
▲ Abstract：
Here we report the astronomical detection of this t?=?0 moment, capturing the building blocks of a new planetary system beginning its assembly. The young protostar HOPS-315 is observed at infrared and millimetre wavelengths with the James Webb Space Telescope (JWST) and the Atacama Large Millimeter Array (ALMA), revealing a reservoir of warm silicon monoxide gas and crystalline silicate minerals low in the atmosphere of a disk within 2.2?AU of the star, physically isolated from the millimetre SiO jet. Comparison with condensation models with rapid grain growth and disk structure models suggests the formation of refractory solids analogous to those in our Solar System. Our results indicate that the environment in the inner disk region is influenced by sublimation of interstellar solids and subsequent refractory solid recondensation from this gas reservoir on timescales comparable with refractory condensation in our own Solar System.
化學Chemistry
Electricity-driven enzymatic dynamic kinetic oxidation
電驅動酶的動態動力學氧化
▲ 作者：Beibei Zhao, Yuanyuan Xu et al.
▲鏈接：
https://www.nature.com/articles/s41586-025-09178-6
▲摘要：
該研究用二茂鐵介導的電催化重塑硫胺素依賴酶，實現了α-支化醛的非天然動態動力學氧化。這種強大的電酶催化方法能低至0.05 mol%的酶負載量在全細胞體系中應用，并高效合成多種生物活性（S）-脯氨酸，對映體過量值高達99%。
機理研究表明，該電酶系統具有精確底物識別、加速外消旋化以及促進動力學匹配的電子轉移過程的多重功能。
▲ Abstract：
Here we report the reshaping of thiamine-dependent enzymes with ferrocene-mediated electrocatalysis to unlock an unnatural dynamic kinetic oxidation of α-branched aldehydes. This robust electroenzymatic approach yields various bioactive (S)-profens with up to 99% enantiomeric excess; it is applicable with whole cells overexpressing the enzyme and using down to 0.05?mol% enzyme loadings. Mechanistic investigations show multiple functions of the electroenzyme in precise substrate discrimination, accelerating racemization and facilitating kinetically matched electron transfer events.
地球科學Earth Science
Global terrestrial nitrogen fixation and its modification by agriculture
全球陸地生態系統氮固定及其農業活動影響
▲ 作者：Carla R. Reis Ely, Steven S. Perakis et al.
▲鏈接：
https://www.nature.com/articles/s41586-025-09201-w
▲摘要：
研究揭示了不確定性部分源于采樣偏差——現有自然陸地生態系統的生物固氮（BNF）測量數據多來自固氮生物豐度達全球平均水平17倍的區域。為校正偏差，研究人員通過空間顯式尺度轉換方法，基于主要生物地球化學固氮生態位分布對實地測量數據進行升尺度估算，獲得全球陸地BNF新估值。
研究發現自然生物群落的BNF總量為65?(52–77)?Tg?N?yr?1，低于既往自下而上的經驗估計，其中熱帶森林和旱地貢獻主要份額；農田和人工草場的農業BNF高達56（54-58）Tg?N?yr?1。
與工業化前相比，農業BNF已使陸地BNF總量提升64%，陸地總氮輸入量增加60%。研究表明，BNF在自然生物群落中可能對碳匯形成更強約束，并且代表農業氮源在全球氮循環中的貢獻被普遍低估，同時現行氮素安全使用限值的設定需重新考量。
▲ Abstract：
Here we show that this uncertainty is partly because of sampling bias, as field BNF measurements in natural terrestrial ecosystems occur where N fixers are 17 times more prevalent than their mean abundances worldwide. To correct this bias, we develop new estimates of global terrestrial BNF by upscaling field BNF measurements using spatially explicit abundances of all major biogeochemical N-fixing niches. We find that natural biomes sustain lower BNF, 65?(52–77)?Tg?N?yr?1, than previous empirical bottom-up estimates, with most BNF occurring in tropical forests and drylands. We also find high agricultural BNF in croplands and cultivated pastures, 56?(54–58)?Tg?N?yr?1. Agricultural BNF has increased terrestrial BNF by 64% and total terrestrial N inputs from all sources by 60% over pre-industrial levels. Our results indicate that BNF may impose stronger constraints on the carbon sink in natural terrestrial biomes and represent a larger source of agricultural N than is generally considered in analyses of the global N cycle, with implications for proposed safe operating limits for N use.
生物學Biology
Eighteen million years of diverse enamel proteomes from the East African Rift
來自東非大裂谷1800萬年前的牙釉質蛋白質組多樣性研究
▲ 作者：Daniel R. Green, Kevin T. Uno et al.
▲鏈接：
https://www.nature.com/articles/s41586-025-09040-9
▲摘要：
研究人員在保存了豐富新生代哺乳動物演化記錄的肯尼亞圖爾卡納盆地，采集了從更新世到漸新世古生物遺址化石牙釉質內部的微量蛋白質組。
通過基于質譜的蛋白質組學工作流程，并采用特定標準定位源自牙釉質的成巖修飾片段，研究人員成功從早中新世犀科化石和若干長鼻目化石中，復原了釉原蛋白、成釉蛋白、基質金屬蛋白酶-20和牙本質基質酸性磷蛋白1的片段。成巖修飾片段數量隨化石年代增加而遞減，且早中新世不同遺址的保存狀況存在顯著差異。
盡管這些序列片段稀疏、鑒定存在不確定性且可能發生成巖序列改變，但系統發育分析表明其對已滅絕類群的分類定位具有重要貢獻。研究鑒定出支持這些蛋白質古老年齡的典型修飾特征，包括迄今已知最古老的晚期糖基化終產物實例。
在地球持續高溫區域之一的致密牙釉質組織中發現蛋白質序列，預示著可能發現更古老的蛋白質組，這將為研究已滅絕類群的古生物學特征和演化關系提供關鍵分子證據。
▲ Abstract：
Here we sample small proteomes from the interior enamel of fossils at palaeontological sites from the Pleistocene to the Oligocene in the Turkana Basin, Kenya, which has produced a rich record of Cenozoic mammalian evolution10. Through a mass-spectrometry-based proteomic workflow, and using criteria to locate diagenetiforms derived from enamel, we recover fragments of enamelin, ameloblastin, matrix metalloprotease-20 and dentin matrix acidic phosphoprotein?1 from an Early Miocene rhinocerotid and several proboscideans collected from the sites of Buluk (16?million years ago; Ma) and Loperot (18?Ma). Diagenetiform counts decline in progressively older fossils, and we observe variability in Early Miocene preservation across sites. Phylogenetic analyses reveal the contribution of these sequences to the systematic placement of extinct taxa, although we caution that this approach must account for sparse fragments, uncertainty in fragment identification and possible sequence diagenesis. We identify likely modifications that support the ancient age of these proteins, and some of the oldest examples of advanced glycation end-products yet known. The discovery of protein sequences within dense enamel tissues in one of the persistently warmest regions on Earth promises the discovery of much older proteomes that will aid in the study of the palaeobiology and evolutionary relationships of extinct taxa.
Motor learning refines thalamic influence on motor cortex
運動學習細化丘腦對運動皮層的調控作用
▲ 作者：Assaf Ramot, Felix H. Taschbach et al.
▲鏈接：
https://www.nature.com/articles/s41586-025-08962-8
▲摘要：
通過使用縱向成像技術追蹤小鼠初級運動皮層（M1）第2/3層的主要輸入來源，研究發現運動丘腦是編碼熟練動作（兩周動物訓練）的關鍵輸入樞紐。
利用光遺傳學技術，研究人員鑒定出學習前后均受丘腦輸入強驅動的M1第2/3層神經元亞群。研究發現，運動學習可重塑丘腦對M1的調控模式，使運動丘腦優先激活編碼熟練動作的M1神經元。抑制熟練期丘腦向M1的輸入會顯著破壞習得動作的執行。該研究揭示了運動學習通過重構丘腦-M1神經環路實現熟練動作的穩定執行。
▲ Abstract：
Here, using longitudinal axonal imaging of the main inputs to M1 L2/3 in mice, we show that the motor thalamus is the key input source that encodes learned movements in experts (animals trained for two weeks). We then use optogenetics to identify the subset of M1 L2/3 neurons that are strongly driven by thalamic inputs before and after learning. We find that the thalamic influence on M1 changes with learning, such that the motor thalamus preferentially activates the M1 neurons that encode learned movements in experts. Inactivation of the thalamic inputs to M1 in experts impairs learned movements. Our study shows that motor learning reshapes the thalamic influence on M1 to enable the reliable execution of learned movements.
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