《天然》（20250227出书）一周论文导读

Nature, 27 February 2025, Volume 638 Issue 8052《天然》2025年2月27日，第638卷，8052期化学ChemistryTotal synthesis of 25 picrotoxanes by virtual library selection经由过程虚构库挑选实现25种木防己苦毒素化合物的全分解▲ 作者：Chunyu Li (李春雨) Ryan A. Shenvi▲ 链接：https://www.nature.com/articles/s41586-024-08538-y▲择要：为懂得决成绩且防止繁琐的试错试验，咱们构建了一个虚构库，此中包括难以捉摸的前期旁边体相似物，这些相似物经由过程反映性停止挑选并转变了分解门路。该方式的效力促进了25种自然木防己苦毒素化合物的简化分解道路。昂贵的密度泛函实践过渡态盘算被更快的反映物参数化所代替，从而进步了可扩大性，并在本研讨中提醒了反映机制。这种方式能够作为人类或盘算机帮助分解计划的附加搜寻东西，实用于高庞杂性目的化合物跟/或文献或反映数据库中代表性缺乏的步调。▲ Abstract：Here, to solve this problem but avoid tedious guess-and-check experimentation, we built a virtual library of elusive late-stage intermediate analogues that were triaged by reactivity and altered the synthesis pathway. The efficiency of this method led to concise routes to 25 naturally occurring picrotoxanes. Costly density-functional-theory transition-state calculations were replaced with faster reactant parameterizations to increase scalability and, in this case, inform the mechanism. This approach can serve as an add-on search to human or computer-assisted synthesis planning applicable to high-complexity targets and/or steps with little representation in the literature or reaction databases.昔人类学PaleoanthropologyAncient DNA reveals reproductive barrier despite shared Avar-period culture现代DNA提醒阿瓦尔时代存在生殖断绝▲ 作者：Ke Wang, Bendeguz Tobias et al.▲ 链接：https://www.nature.com/articles/s41586-024-08418-5▲择要：公元567至568年，存在东亚血缘的阿瓦尔人经由远程迁移到达了东中欧，并与存在欧洲血缘的群体相遇。咱们应用722个集体的现代全基因组数据，并联合对维也纳南部两处年夜型七至八世纪相邻坟场的精致跨学科剖析，探究这一相遇在数百年间的影响。咱们发明，即便在200年后，一处遗迹（莱奥贝斯多夫）的血缘仍以东亚为主，而另一处遗迹（默德林）则表现出当地欧洲血缘。只管这两处相邻遗迹共享奇特的晚期阿瓦尔文明，但它们之间的生物学亲缘关联却十分无限。咱们重修了两处遗迹的六代家谱，涵盖多达450名远亲集体，从而对社区停止逐代生齿统计剖析。只管血缘差别，但这些家谱以及普遍的近亲关联收集表现，远亲滋生景象不存在，父系形式与女性外婚制并存，存在多更生殖搭档关联（如娶寡嫂制），而且生物学连通性与社会位置的考古标志直接相干。这种代际遗传屏蔽的保持，是经由过程体系性地抉择来自阿瓦尔范畴内其余遗迹的存在类似血缘的朋友实现的。莱奥贝斯多夫与阿瓦尔中心地域的生物学接洽比与默德林更为严密，而默德林则与维也纳盆地的另一处存在欧洲血缘的遗迹相干联。遗迹之间的活动性重要源于女性外婚制，标明差别的婚姻收集是保持遗传屏蔽的重要驱能源。▲ Abstract：After a long-distance migration, Avars with Eastern Asian ancestry arrived in Eastern Central Europe in 567 to 568 CE and encountered groups with very different European ancestry. We used ancient genome-wide data of 722 individuals and fine-grained interdisciplinary analysis of large seventh- to eighth-century CE neighbouring cemeteries south of Vienna (Austria) to address the centuries-long impact of this encounter. We found that even 200?years after immigration, the ancestry at one site (Leobersdorf) remained dominantly East Asian-like, whereas the other site (M?dling) shows local, European-like ancestry. These two near欧洲杯买球正规官网by sites show little biological relatedness, despite sharing a distinctive late-Avar culture. We reconstructed six-generation pedigrees at both sites including up to 450 closely related individuals, allowing per-generation demographic profiling of the communities. Despite different ancestry, these pedigrees together with large networks of distant relatedness show absence of consanguinity, patrilineal pattern with female exogamy, multiple reproductive partnerships (for example, levirate) and direct correlation of biological connectivity with archaeological markers of social status. The generation-long genetic barrier was maintained by systematically choosing partners with similar ancestry from other sites in the Avar realm. Leobersdorf had more biological connections with the Ava皇冠新体育官网r heartlands than with M?dling, which is instead linked to another site from the Vienna Basin with European-like ancestry. Mobility between sites was mostly due to female exogamy pointing to different marriage networks as the main driver of the maintenance of the genetic barrier.地球迷信Earth ScienceContinued Atlantic overturning circulation even under climate extremes年夜西洋经向翻转环流在极其气象下依然连续▲ 作者：J. A. Baker, M. J. Bell et al.▲ 链接：https://www.nature.com/articles/s41586-024-08544-0▲ 择要：咱们展现了年夜西洋365速发国际官网经向翻转环流（AMOC）在34个气象模子中对极其温室气体跟北年夜西洋海水逼迫表示出顺应性。由连续的南年夜洋风驱动的南年夜洋回升流保持了AMOC的削弱状况，避免其完整瓦解。因为南年夜洋回升流必需经由过程年夜西洋或平静洋的下沉流来均衡，因而只有在弥补性的平静洋经向翻转环流（PMOC）开展时，AMOC才可能瓦解。值得留神的是，多少乎全部模子中都呈现了PMOC，但其强度缺乏以均衡全部南年夜洋回升流，这标明本世纪AMOC瓦解的可能性较低。咱们的研讨提醒了AMOC的稳固机制，这些机制对从前跟将来的AMOC变更存在主要意思，进而对生态体系跟大陆生物地球化学发生影响。研讨还标明，急切须要更好地舆解跟评价南年夜洋跟印度—平静洋环流，以正确猜测将来AMOC的变更。▲ Abstract：Here we show that the The Atlantic Meridional Overturning Circulation (AMOC) is resilient to extreme greenhouse gas and North Atlantic freshwater forcings across 34 climate models. Upwelling in the Southern Ocean, driven by persistent Southern Ocean winds, sustains a weakened AMOC in all cases, preventing its complete collapse. As Southern Ocean upwelling must be balanced by downwelling in the Atlantic or Pacific, the AMOC can only collapse if a compensating Pacific Meridional Overturning Circulation (PMOC) develops. Remarkably, a PMOC does emerge in almost all models, but it is too weak to balance all of the Southern Ocean upwelling, suggesting that an AMOC collapse is unlikely this century. Our findings reveal AMOC-stabilizing mechanisms with implications for past and future AMOC changes, and hence for ecosystems and ocean biogeochemistry. They suggest that better understanding and estimates of the Southern Ocean and Indo-Pacific circulations are urgently needed to accurately predict future AMOC change.Warming and cooling catalyse widespread temporal turnover in biodiversity变暖与降温催化了生物多样性的普遍时光更替▲ 作者：Malin L. Pinsky, Helmut Hillebrand et al.▲ 链接：https://www.nature.com/articles/s41586-024-08456-z▲择要：咱们剖析了来自大陆、海洋跟海水群落的42225个物种构成的时光序列。成果标明，在阅历更快温度变更（包含变温暖降温）的所在，时光更替率一直更快。别的，那些难以进入微气象遁迹所或面对更能人类影响的陆生群落对温度变更尤为敏感，每十年物种更替率高达48%。这些成果提醒了对连续气象变更的普遍懦弱性旌旗灯号，并凸起了哪些生态群落最为敏感，从而激发了对生态体系完全性的担心，由于气象变更跟其余人类影响正在减速。▲ Abstract：Here we analyse 42,225 time series of species composition from marine, terrestrial and freshwater assemblages, and show that temporal rates of turnover were consistently faster in locations that experienced faster temperature change, including both warming and cooling. In addition, assemblages with limited access to microclimate refugia or that faced stronger human impacts on land were especially responsive to temperature change, with up to 48% of species replaced per decade. These results reveal a widespread signal of vulnerability to continuing climate change and highlight which ecological communities are most sensitive, raising concerns about ecosystem integrity as climate change and other human impacts accelerate.生物学BiologyWidespread occurrence and relevance of phosphate storage in foraminifera磷酸盐在有孔虫中贮存的普遍性及相干性▲ 作者：Nicolaas Glock, Julien Richirt et al.▲ 链接：https://www.nature.com/articles/s41586-024-08431-8▲ 择要：咱们展现了磷酸盐贮存在有孔虫中是普遍存在的，从潮滩到深海均有发明。在瓦登海里，底栖有孔虫Ammonia confertitesta在水华时期细胞内贮存的磷酸盐总量高达德国每年磷肥耗费量的约5%。对南北海跟秘鲁氧最小区的估算盘算标明，底栖有孔虫可能在南北海缓冲河道磷径流约37天，在秘鲁边沿缓冲约21天。这标明这些生物可能对大陆磷轮回存在主要意思——它们可能在沿海情况中为工资富养分化的情形停止缓冲。磷酸盐以多聚磷酸盐的情势贮存在细胞器中，这些细胞器可能是酸性钙化体。它们的代谢功效可能包含调理浸透压、细胞内pH值以及钙跟能量贮存。别的，贮存高能磷化合物（如磷酸肌酸跟多磷酸）可能是有孔虫对氧气耗竭的一种顺应机制。▲ Abstract：Here we show that phosphate storage in foraminifera is widespread, from tidal flats to the deep sea. The total amount of intracellular phosphate stored in the benthic foraminifer Ammonia confertitesta in the Wadden Sea during a bloom is as high as around 5% of the annual consumption of phosphorus (P) fertilizer in Germany. Budget calculations for the Southern North Sea and the Peruvian Oxygen Minimum Zone indicate that benthic foraminifera may buffer riverine P runoff for approximately 37?days at the Southern North Sea and for about 21?days at the Peruvian margin. This indicates that these organisms are probably relevant for marine P cycling—they potentially buffer anthropogenic eutrophication in coastal environments. Phosphate is stored as polyphosphate in cell organelles that are potentially acidocalcisomes. Their metabolic functions can range from regulation of osmotic pressure and intracellular pH to calcium and energy storage. In addition, storage of energetic P compounds, such as creatine phosphate and polyphosphate, is probably an adaptation of foraminifera to O2 depletion.Learned magnetic map cues and two mechanisms of magnetoreception in turtles海龟进修磁舆图的线索与两种磁感到机制▲ 作者：Kayla M. Goforth, Catherine M. F. Lohmann et al.▲ 链接：https://www.nature.com/articles/s41586-024-08554-y▲择要：临时以来，人们始终以为，植物要应用地磁舆图停止导航，必需懂得目标地的地磁坐标。但是，对于植物可能进修地舆地区地磁特点的要害假设尚未失掉验证。咱们讲演一种标记性的导航物种——红海龟（Caretta caretta）可能进修此类信息。当在模仿特定大陆地位地磁场的磁场中被重复喂食时，少小海龟学会了辨别它们碰到食品的磁场与其余处所的磁场，这种才能可能是其寻食所在虔诚性的基本。在这种新的地磁舆图测试中，前提反射不受射频振荡磁场的影响，而射频振荡磁场应当会损坏基于自在基对的化学磁感触机制，这标明海龟的地磁舆图感知并不依附这种机制。比拟之下，须要应用磁罗盘的定向行动则会被射频振荡磁场烦扰。这些发明供给了证据，标明海龟的地磁舆图跟“磁罗盘”依附于两种差别的磁感到机制。▲ Abstract：It has long been proposed that, to navigate using a magnetic map, animals must learn the magnetic coordinates of the destination, yet the pivotal hypothesis that animals can learn magnetic signatures of geographical areas has, to our knowledge, yet to be tested. Here we report that an iconic navigating species, the loggerhead turtle (Caretta caretta), can learn such information. When fed repeatedly in magnetic fields replicating those that exist in particular oceanic locations, juvenile turtles learned to distinguish magnetic fields in which they encountered food from magnetic fields that exist elsewhere, an ability that might underlie foraging site fidelity. Conditioned responses in this new magnetic map assay were unaffected by radiofrequency oscillating magnetic fields, a treatment expected to disrupt radical-pair-based chemical magnetoreception, suggesting that the magnetic map sense of the turtle does not rely on this mechanism. By contrast, orientation behaviour that required use of the magnetic compass was disrupted by radiofrequency oscillating magnetic fields. The findings provide evidence that two different mechanisms of magnetoreception underlie the magnetic map and magnetic compass in sea turtles.