Proceedings of the National Academy of Sciences of the United States of America最新文献

{"title":"From propulsion to suction: Unraveling thrust reversal in propellers at intermediate Reynolds numbers.","authors":"Rong Fu,Siyu Li,Yang Ding","doi":"10.1073/pnas.2504153122","DOIUrl":"https://doi.org/10.1073/pnas.2504153122","url":null,"abstract":"This study investigates propeller hydrodynamics at intermediate Reynolds numbers (Re), crucial for small-scale robotic systems but still uncharted. Experiments on a propeller-driven underwater vehicle and numerical simulations reveal thrust reversal-a phenomenon where clockwise propeller rotation leads to backward motion-in the approximate range 1.3 ≲ Re ≲ 150 under specific conditions. Notably, counterclockwise rotation consistently results in backward motion. Simulations reveal that this behavior arises when centrifugal suction, an inward force along the axis caused by radial outward flow from the propeller's rotation, dominates over fluid backward acceleration, the primary thrust mechanism at high Re. These findings provide critical insights into the unique dynamics of the intermediate Re regime and inform the design of efficient propulsion systems for miniature aquatic robots.","PeriodicalId":20548,"journal":{"name":"Proceedings of the National Academy of Sciences of the United States of America","volume":"28 1","pages":"e2504153122"},"PeriodicalIF":11.1,"publicationDate":"2025-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145209034","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Chemobiological synthesis of benzene, toluene, ethylbenzene, and xylene from glucose or glycerol.","authors":"Xuan Zou,Taewan Kim,Zi Wei Luo,Kyeong Rok Choi,Sunkyu Han,Sang Yup Lee","doi":"10.1073/pnas.2509568122","DOIUrl":"https://doi.org/10.1073/pnas.2509568122","url":null,"abstract":"Benzene, toluene, ethylbenzene, and p-xylene (BTEX) are key aromatic hydrocarbons widely used in fuels, polymers, and industrial chemicals, yet their production remains heavily dependent on fossil resources, raising environmental and public health concerns. To promote de novo production of BTEX from renewable feedstocks, we developed a chemobiological platform that integrates microbial biosynthesis with chemical deoxygenation. Four metabolically engineered Escherichia coli strains were constructed to produce one of four oxygenated precursors of BTEX-phenol, benzyl alcohol, 2-phenylethanol, or 2,5-xylenol-from glucose or glycerol. After in situ two-phase extractive fermentation of the individual engineered strains using isopropyl myristate (IPM) as the organic solvent, the organic phase containing one of the oxygenated precursors was separated from the aqueous phase and subjected to distinct chemical deoxygenation reactions to reduce the precursor to the corresponding BTEX compound. This modular approach, based on the compatible organic solvent, streamlines biotransformation and consecutive chemical derivatization, providing a practical and viable route to sustainable BTEX production. The platform is extensible and provides a generalizable framework for integrating biosynthesis with chemical deoxygenation in hybrid bioprocessing.","PeriodicalId":20548,"journal":{"name":"Proceedings of the National Academy of Sciences of the United States of America","volume":"506 1","pages":"e2509568122"},"PeriodicalIF":11.1,"publicationDate":"2025-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145209033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mouse X-linked microRNA cluster regulates the meiotic checkpoint and Prdm9-driven hybrid sterility in a copy number-dependent manner.","authors":"Petr Jansa,Giordano Tanieli,Kim Vucinic,Diana Lustyk,Karel Fusek,Barbora Valiskova,Kento Morimoto,Seiya Mizuno,Kristian Ullrich,Linda Odenthal-Hesse,Jan Provaznik,Vladimir Benes,Lucie Pfeiferova,Michal Kolar,Václav Gergelits,Jaroslav Pialek,Jiri Forejt","doi":"10.1073/pnas.2510229122","DOIUrl":"https://doi.org/10.1073/pnas.2510229122","url":null,"abstract":"One of the reproductive barriers between diverging populations during formation of a new species is the sterility of their hybrids. The Prdm9-driven hybrid male sterility of Mus musculus musculus × Mus musculus domesticus hybrids depends on the interaction between PRDM9, a histone methyltransferase that determines the positions of meiotic recombination hotspots, and an as yet unknown X-linked genetic factor within the Hybrid sterility X2 (Hstx2) locus. Here, we report that the Mir465 microRNA (miRNA) gene cluster is the predicted Hstx2 hybrid sterility factor. We show that removal of the Mir465 genes restores the fertility of sterile hybrids and improves meiotic synapsis of homologous chromosomes. Mir465 knockout also restores spermatogenesis in sterile chromosomal translocation carriers, demonstrating that Mir465 acts as a meiotic checkpoint that can be activated independently of Prdm9 intersubspecific incompatibility. Furthermore, the Mir465 knockout increases the global recombination rate in hybrids and in parental Mus m. domesticus mice. This demonstrates that Mir465 is responsible for the phenotypes of the two overlapping genetic loci, the Hstx2 engaged in fertility of hybrids and the Meiotic recombination 1 (Meir1) controlling the recombination rate. The finding of enlarged Mir465 clusters in all European Mus m. musculus samples tested and the identification of differentially expressed targets suggest that the reproductive barrier between the two subspecies is sensitive to copy number variation of Mir465 genes. Together, the underdominant interaction between Prdm9 and Mir465 provides a rare example of Dobzhansky-Muller incompatibility in hybrids of closely related species, making it accessible for further analysis at the molecular level.","PeriodicalId":20548,"journal":{"name":"Proceedings of the National Academy of Sciences of the United States of America","volume":"68 1","pages":"e2510229122"},"PeriodicalIF":11.1,"publicationDate":"2025-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145209035","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identification of claudin-3 as an entry factor for rat hepacivirus","authors":"Tomohisa Tanaka, Yasunori Akaike, Hirotake Kasai, Atsuya Yamashita, Yoshiharu Matsuura, Kohji Moriishi","doi":"10.1073/pnas.2508736122","DOIUrl":"https://doi.org/10.1073/pnas.2508736122","url":null,"abstract":"Approximately 58 million people worldwide are believed to be infected with hepatitis C virus (HCV), a major causative agent of chronic liver diseases. <jats:italic toggle=\"yes\">Hepacivirus ratti</jats:italic> strain rn-1, which was discovered from Rattus norvegicus (Norway rat) and designated Norway rat hepacivirus 1 (NRHV1), shares similar properties with HCV in terms of genetic homology, target cell tropism, pathogenicity, and the immune response. In vivo infection systems for NRHV1 will help overcome the challenges in HCV research for vaccine development. However, the virological characteristics of NRHV1, such as the mechanisms of cell entry, remain largely unexplored, in part owing to a paucity of cell culture systems for NRHV1. Here, we identified the host factors that facilitate NRHV1 entry by profiling the gene expression of two cell lines with different susceptibilities to NRHV1 infection. NRHV1 employs rodent orthologues of HCV entry factors, including scavenger receptor class BI, CD81, and occludin, and utilizes claudin-3 (CLDN3) but not claudin-1. The expression of rat and mouse, but not human, CLDN3 facilitates the entry of NRHV1 into murine cell lines that are nonsusceptible to NRHV1 infection. The host-specific cell entry of CLDN3 is determined by two amino acid residues, Ile <jats:sup>44</jats:sup> and Trp <jats:sup>46</jats:sup> , in extracellular loop 1. These findings suggest that CLDN3 serves as an entry factor for rat hepacivirus.","PeriodicalId":20548,"journal":{"name":"Proceedings of the National Academy of Sciences of the United States of America","volume":"7 1","pages":""},"PeriodicalIF":11.1,"publicationDate":"2025-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145209944","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The intrinsic neuronal network of the central nervous system and its modular (subsystem) architecture in a mammal.","authors":"Larry W Swanson,Joel D Hahn,Olaf Sporns","doi":"10.1073/pnas.2519768122","DOIUrl":"https://doi.org/10.1073/pnas.2519768122","url":null,"abstract":"The vertebrate central nervous system (CNS) has two great topographic divisions-brain and spinal cord-that together integrate the body's internal physiology and behavioral interactions with the environment. To clarify the architecture of intra-CNS connectivity supporting this integration in a mammal (rat), network science analyses were applied at the level of gray matter regions (nodes) connected by directed and weighted axonal projections. Neuroanatomical evidence indicates a bilateral, predominantly sexually monomorphic neuronal network of 840 nodes and a projected 81,434 direct interconnections (of the 704,760 possible connections), representing a projected network density of 12%; 32% of identified connections terminate contralaterally, and 41% of identified connections participate in bidirectionally linking a pair of nodes. Local network differentiations examined with unsupervised multiresolution consensus cluster analysis revealed a nested hierarchy of interconnected modules (clusters or subsystems) that were conservatively assigned putative functional roles. This structure-function hierarchy includes only three first-order modules, indicating a tripartite systems architecture (distinct from the bipartite brain-spinal cord topographic division): a bilaterally symmetric module pair centered in the forebrain-midbrain, associated with behavior control, cognition, and affect; and a single bilateral module centered in the rhombicbrain-spinal cord, associated with behavior execution and reflex integration. This modular spatial patterning suggests possible developmental and phylogenetic correlates. Additional analyses of the CNS's basic structural network plan included global neuronal network features-specifically, measures of centrality, rich club, and small world topology-that transcend modular boundaries.","PeriodicalId":20548,"journal":{"name":"Proceedings of the National Academy of Sciences of the United States of America","volume":"27 1","pages":"e2519768122"},"PeriodicalIF":11.1,"publicationDate":"2025-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145209030","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reaction-induced departures from continuum Navier-Stokes turbulence.","authors":"Christopher T Williams,Ryan M McMullen,Michael A Gallis","doi":"10.1073/pnas.2508608122","DOIUrl":"https://doi.org/10.1073/pnas.2508608122","url":null,"abstract":"Reactive hydrodynamic turbulence is an inherently multiscale phenomenon, characterized by the separation between energy-containing, viscous, and molecular length and time scales. The separation between the viscous scale (the Kolmogorov scale) and the molecular mean free path ostensibly justifies a macroscopic description of reactive turbulence via the Navier-Stokes (NS) equations. However, here we use molecular-level simulations to demonstrate that exothermic bimolecular reactions can cause the NS description of turbulence to break down in the near-continuum regime. Sufficiently energetic heat-releasing reactive collisions strongly distort the Maxwell-Boltzmann velocity distribution function, modifying not only the macroscopic chemical rate law but the kinetic-energy-transfer processes as well. This translational nonequilibrium ultimately introduces significant departures from the NS description in the kinetic energy spectra at scales orders of magnitude larger than both the molecular mean free path and the Kolmogorov length scale. These departures prove substantial enough to meaningfully alter integrated quantities, including the overall turbulence kinetic energy itself.","PeriodicalId":20548,"journal":{"name":"Proceedings of the National Academy of Sciences of the United States of America","volume":"98 1","pages":"e2508608122"},"PeriodicalIF":11.1,"publicationDate":"2025-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145209038","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Electrostatics and viscosity are strongly linked in concentrated antibody solutions","authors":"Fabrizio Camerin, Marco Polimeni, Anna Stradner, Emanuela Zaccarelli, Peter Schurtenberger","doi":"10.1073/pnas.2425974122","DOIUrl":"https://doi.org/10.1073/pnas.2425974122","url":null,"abstract":"Monoclonal antibodies are among the most promising therapeutic agents in modern medicine, yet their formulation into high-concentration solutions for subcutaneous self-administration poses a major challenge. A key obstacle is the marked increase in viscosity often observed under these conditions. To gain deeper insights into this phenomenon, coarse-grained models derived from soft matter physics have been widely employed. However, these models have yet to be fully leveraged for analyzing the rheological collective properties of such systems. In this study, using molecular dynamics simulations, we directly compute the antibody solution viscosity by starting from commonly used models in which electrostatic interactions are treated through effective screened Coulomb potentials. We demonstrate that this approach fails to reproduce experimental evidence and we show, by analyzing stress correlations in the system, that it is necessary to treat the heterogeneously charged domains with explicit Coulomb interactions, also including counterions and salt ions. By thoroughly analyzing the microscopic structure of the system, we further reveal the presence of transient strongly correlated antibodies which would not be present if charges were treated implicitly, thus pointing to a prominent role of electrostatics in determining the increase in viscosity at high concentrations. By taking advantage of our realistic treatment, new approaches can be devised to ensure that antibody solutions exhibit the desired characteristics for their intended broad use and effective deployment.","PeriodicalId":20548,"journal":{"name":"Proceedings of the National Academy of Sciences of the United States of America","volume":"3 1","pages":""},"PeriodicalIF":11.1,"publicationDate":"2025-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145209733","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Forest biodiversity increases productivity via complementarity from greater canopy structural complexity","authors":"Xianglu Deng, Bernhard Schmid, Helge Bruelheide, Chen Chen, Yi Li, Shan Li, Felix Morsdorf, Tama Ray, Meredith C. Schuman, Ting Tang, Goddert von Oheimb, Keping Ma, Xiaojuan Liu","doi":"10.1073/pnas.2506750122","DOIUrl":"https://doi.org/10.1073/pnas.2506750122","url":null,"abstract":"The horizontal distribution and vertical stratification of tree crowns can affect light interception and tree growth, thus driving forest productivity and carbon storage. However, how canopy structure is affected by tree diversity and thus can mediate its effects on productivity remains unclear. Using 4-y consecutive unmanned aerial vehicle-borne light detection and ranging and ground-based growth measurements from 482 plots and 38,088 trees, 11 to 15 y after planting, within a large-scale forest biodiversity experiment in southeast China, we found that increased canopy structural complexity consistently explains the positive effects of tree diversity on productivity. Species complementarity was the main mediator of diversity-enhanced productivity, with the positive complementarity effects strengthening over time. Our study underscores the importance of establishing multispecies forest communities with complex canopy structure to maximize productivity and carbon sequestration in forest ecosystems.","PeriodicalId":20548,"journal":{"name":"Proceedings of the National Academy of Sciences of the United States of America","volume":"38 1","pages":""},"PeriodicalIF":11.1,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145203500","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Aluminum speciation identification reveals water interactions in silicoaluminophosphate zeolites","authors":"Caiyi Lou, Wenna Zhang, Pan Gao, Yida Zhou, Yuchun Zhi, Fangxiu Ye, Wenfu Yan, Shutao Xu, Yingxu Wei, Zhongmin Liu","doi":"10.1073/pnas.2507802122","DOIUrl":"https://doi.org/10.1073/pnas.2507802122","url":null,"abstract":"Water plays a crucial role in material development. As it is ubiquitous throughout zeolite generation and application, host–guest interaction between zeolite and water attracts broad interest, but mechanistic understanding remains fragmented. Here, advanced solid-state NMR techniques (2D <jats:sup>17</jats:sup> O SPAM-MQ, <jats:sup>27</jats:sup> Al{ <jats:sup>31</jats:sup> P} <jats:italic toggle=\"yes\">J</jats:italic> -HMQC, <jats:sup>27</jats:sup> Al{ <jats:sup>29</jats:sup> Si} REDOR, and <jats:sup>1</jats:sup> H TQ-SQ NMR) combined with isotopic tracing and theoretical calculations determine water-induced octahedrally coordinated aluminum in silicoaluminophosphate molecular sieves (SAPOs) as an exclusive product of Al(OP) <jats:sub>4</jats:sub> units coordinated with two water molecules—a structure distinct from that in aluminosilicates. Based on the knowledge of aluminum speciation, we elucidate four water interaction mechanisms in SAPOs, including Brønsted-acid interaction, coordination, reversible/irreversible hydrolysis, and capillary condensation. Contrary to conventional wisdom attributing SAPO degradation to Al-O-P hydrolysis, we clarify that desilication dominates structural collapse, establishing Si environments as catalyst durability descriptors. These mechanistic insights decipher the nature of SAPO interacting with water and its fundamental differences from aluminosilicate zeolite.","PeriodicalId":20548,"journal":{"name":"Proceedings of the National Academy of Sciences of the United States of America","volume":"29 16 1","pages":""},"PeriodicalIF":11.1,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145203499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Correction for Sakuma et al., Liver lipid droplet cholesterol content is a key determinant of metabolic dysfunction-associated steatohepatitis.","authors":"","doi":"10.1073/pnas.2524902122","DOIUrl":"https://doi.org/10.1073/pnas.2524902122","url":null,"abstract":"","PeriodicalId":20548,"journal":{"name":"Proceedings of the National Academy of Sciences of the United States of America","volume":"124 1","pages":"e2524902122"},"PeriodicalIF":11.1,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145203534","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}