Proceedings of the National Academy of Sciences of the United States of America最新文献_第10页

Active control of mitochondrial network morphology by metabolism-driven redox state 代谢驱动氧化还原状态对线粒体网络形态的主动控制

IF 11.1 1区综合性期刊

Proceedings of the National Academy of Sciences of the United States of America Pub Date : 2025-04-17 DOI: 10.1073/pnas.2421953122

Gaurav Singh, Vineeth Vengayil, Aayushee Khanna, Swagata Adhikary, Sunil Laxman

{"title":"Active control of mitochondrial network morphology by metabolism-driven redox state","authors":"Gaurav Singh, Vineeth Vengayil, Aayushee Khanna, Swagata Adhikary, Sunil Laxman","doi":"10.1073/pnas.2421953122","DOIUrl":"https://doi.org/10.1073/pnas.2421953122","url":null,"abstract":"Mitochondria are dynamic organelles that constantly change morphology. What controls mitochondrial morphology however remains unresolved. Using actively respiring yeast cells growing in distinct carbon sources, we find that mitochondrial morphology and activity are unrelated. Cells can exhibit fragmented or networked mitochondrial morphology in different nutrient environments independent of mitochondrial activity. Instead, mitochondrial morphology is controlled by the intracellular redox state, which itself depends on the nature of electron entry into the electron transport chain (ETC)—through complex I/II or directly to coenzyme Q/cytochrome c. In metabolic conditions where direct electron entry is high, reactive oxygen species (ROS) increase, resulting in an oxidized cytosolic environment and rapid mitochondrial fragmentation. Decreasing direct electron entry into the ETC by genetic or chemical means, or reducing the cytosolic environment rapidly restores networked morphologies. Using controlled disruptions of electron flow to alter ROS and redox state, we demonstrate minute-scale, reversible control between networked and fragmented forms in an activity-independent manner. Mechanistically, the fission machinery through Dnm1 responds in minute-scale to redox state changes, preceding the change in mitochondrial form. Thus, the metabolic state of the cell and its consequent cellular redox state actively control mitochondrial form.","PeriodicalId":20548,"journal":{"name":"Proceedings of the National Academy of Sciences of the United States of America","volume":"30 1","pages":""},"PeriodicalIF":11.1,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143847229","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}

引用次数: 0

Cleavage cascade of the sigma regulator FecR orchestrates TonB-dependent signal transduction sigma调节因子FecR的切割级联协调tonb依赖的信号转导

IF 11.1 1区综合性期刊

Proceedings of the National Academy of Sciences of the United States of America Pub Date : 2025-04-17 DOI: 10.1073/pnas.2500366122

Tatsuhiko Yokoyama, Ryoji Miyazaki, Takehiro Suzuki, Naoshi Dohmae, Hiroki Nagai, Tomoya Tsukazaki, Tomoko Kubori, Yoshinori Akiyama

{"title":"Cleavage cascade of the sigma regulator FecR orchestrates TonB-dependent signal transduction","authors":"Tatsuhiko Yokoyama, Ryoji Miyazaki, Takehiro Suzuki, Naoshi Dohmae, Hiroki Nagai, Tomoya Tsukazaki, Tomoko Kubori, Yoshinori Akiyama","doi":"10.1073/pnas.2500366122","DOIUrl":"https://doi.org/10.1073/pnas.2500366122","url":null,"abstract":"TonB-dependent signal transduction is a versatile mechanism observed in gram-negative bacteria that integrates energy-dependent substrate transport with signal relay. In Escherichia coli , the TonB–ExbBD motor complex energizes the TonB-dependent outer membrane transporter FecA, facilitating ferric citrate import. FecA also acts as a sensor, transmitting signals to the cytoplasmic membrane protein FecR, which eventually activates the cytoplasmic sigma factor FecI, driving transcription of the fec operon. Building on our previous finding that FecR undergoes functional maturation through a three-step cleavage process [T. Yokoyama et al., J. Biol. Chem. 296 , 100673 (2021)], we here describe the complete mechanism of FecR-mediated ferric citrate signaling involving FecA and TonB. The cleavage cascade begins with FecR autoproteolysis prior to membrane integration. The soluble C-terminal domain (CTD) fragment of FecR is cotranslocated with the N-terminal domain (NTD) fragment through a twin-arginine translocation (Tat) system–mediated process. In the periplasm, the interaction between the CTD and NTD fragments prevents further cleavage. Binding of ferric citrate induces a conformational change in FecA, exposing its TonB box to the periplasmic space. This structural alteration is transmitted to the interacting FecR CTD via the motor function of TonB, resulting in the release of the CTD blockage from the NTD. Consequently, the successive cleavage of FecR’s NTD is initiated, culminating in the ferric citrate signal–induced activation of fec gene expression. Our findings reveal that the regulation of FecR cleavage, controlled by the TonB–FecA axis, plays a central role in the bacterial response to ferric citrate signals.","PeriodicalId":20548,"journal":{"name":"Proceedings of the National Academy of Sciences of the United States of America","volume":"9 1","pages":""},"PeriodicalIF":11.1,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143847217","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}

引用次数: 0

Elevated brain manganese induces motor disease by upregulating the kynurenine pathway of tryptophan metabolism. 脑锰升高通过上调色氨酸代谢的犬尿氨酸途径诱发运动疾病。

IF 11.1 1区综合性期刊

Proceedings of the National Academy of Sciences of the United States of America Pub Date : 2025-04-17 DOI: 10.1073/pnas.2423628122

Anna S Warden,Nishant Sharma,Steven Hutchens,Chunyi Liu,Noah R Haggerty,Kerem C Gurol,Thomas Jursa,Donald R Smith,Roy Dayne Mayfield,Somshuvra Mukhopadhyay

{"title":"Elevated brain manganese induces motor disease by upregulating the kynurenine pathway of tryptophan metabolism.","authors":"Anna S Warden,Nishant Sharma,Steven Hutchens,Chunyi Liu,Noah R Haggerty,Kerem C Gurol,Thomas Jursa,Donald R Smith,Roy Dayne Mayfield,Somshuvra Mukhopadhyay","doi":"10.1073/pnas.2423628122","DOIUrl":"https://doi.org/10.1073/pnas.2423628122","url":null,"abstract":"Elevated brain levels of the essential metals manganese (Mn), copper, or iron induce motor disease. However, mechanisms of metal-induced motor disease are unclear and treatments are lacking. Elucidating the mechanisms of Mn-induced motor disease is particularly important because occupational and environmental Mn overexposure is a global public health problem. To address this, here we combined unbiased transcriptomics and metabolomics with functional studies in a mouse model of human environmental Mn exposure. Transcriptomics unexpectedly revealed that Mn exposure up-regulated expression of metabolic pathways in the brain and liver. Notably, genes in the kynurenine pathway of tryptophan metabolism, which produces neuroactive metabolites that impact neurological function, were up-regulated by Mn. Subsequent unbiased metabolomics revealed that Mn treatment altered kynurenine pathway metabolites in the brain and liver. Functional experiments then demonstrated that pharmacological inhibition of the first and rate-limiting step of the kynurenine pathway fully rescued Mn-induced motor deficits. Finally, elevated Mn directly activates hypoxia-inducible factor (HIF) transcription factors, and additional mechanistic assays identified a role for HIF1, but not HIF2, in regulating expression of hepatic kynurenine pathway genes under physiological or Mn exposure conditions, suggesting that Mn-induced HIF1 activation may contribute to the dysregulation of the kynurenine pathway in Mn toxicity. These findings (1) identify the upregulation of the kynurenine pathway by elevated Mn as a fundamental mechanism of Mn-induced motor deficits; (2) provide a pharmacological approach to treat Mn-induced motor disease; and (3) should broadly advance understanding of the general principles underlying neuromotor deficits caused by metal toxicity.","PeriodicalId":20548,"journal":{"name":"Proceedings of the National Academy of Sciences of the United States of America","volume":"108 1","pages":"e2423628122"},"PeriodicalIF":11.1,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143846309","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}

引用次数: 0

Profile of John Hopfield and Geoffrey Hinton: 2024 Nobel laureates in physics. 约翰·霍普菲尔德和杰弗里·辛顿简介：2024年诺贝尔物理学奖得主。

IF 11.1 1区综合性期刊

Proceedings of the National Academy of Sciences of the United States of America Pub Date : 2025-04-17 DOI: 10.1073/pnas.2423094122

James L McClelland

引用次数: 0

Pulse timing dominates binaural hearing with cochlear implants. 脉冲时间控制双耳听力与人工耳蜗植入。

IF 11.1 1区综合性期刊

Proceedings of the National Academy of Sciences of the United States of America Pub Date : 2025-04-17 DOI: 10.1073/pnas.2416697122

Jan W H Schnupp,Sarah Buchholz,Alexa N Buck,Henrike Budig,Lakshay Khurana,Nicole Rosskothen-Kuhl

{"title":"Pulse timing dominates binaural hearing with cochlear implants.","authors":"Jan W H Schnupp,Sarah Buchholz,Alexa N Buck,Henrike Budig,Lakshay Khurana,Nicole Rosskothen-Kuhl","doi":"10.1073/pnas.2416697122","DOIUrl":"https://doi.org/10.1073/pnas.2416697122","url":null,"abstract":"Although cochlear implants (CIs) provide valuable auditory information to more than one million profoundly deaf patients, these devices remain inadequate in conveying fine timing cues. Early deaf patients in particular struggle to use interaural time differences (ITDs) for spatial hearing and auditory scene analysis. Why CI patients experience these limitations remains controversial. One possible explanation, which we investigate here, is that the stimulation by clinical CIs is inappropriate, as it encodes temporal features of sounds only in the envelope of electrical pulse trains, not the pulse timing. We have recently demonstrated that early deaf, adult implanted rats fitted with bilateral CIs that deliver carefully timed pulses routinely develop sensitivity to very small ITDs. Here we show that, while the early deafened mammalian auditory pathway can innately easily resolve pulse timing ITDs as small as 80 µs, it is many times less sensitive to the ITDs of pulse train envelopes. Our results indicate that the stimulation strategies in current clinical use do not present ITD cues in a manner that the inexperienced auditory pathway is highly sensitive to. This may deprive early deaf CI patients of the opportunity to hone their submillisecond temporal processing skills as they learn to hear through their prosthetic devices.","PeriodicalId":20548,"journal":{"name":"Proceedings of the National Academy of Sciences of the United States of America","volume":"30 1","pages":"e2416697122"},"PeriodicalIF":11.1,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143846312","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}

引用次数: 0

Verapamil and its metabolite norverapamil inhibit the Mycobacterium tuberculosis MmpS5L5 efflux pump to increase bedaquiline activity. 维拉帕米及其代谢物诺维拉帕米抑制结核分枝杆菌MmpS5L5外排泵，增加贝达喹啉活性。

IF 11.1 1区综合性期刊

Proceedings of the National Academy of Sciences of the United States of America Pub Date : 2025-04-17 DOI: 10.1073/pnas.2426827122

Adam J Fountain,Natalie J E Waller,Chen-Yi Cheung,William Jowsey,Michael T Chrisp,Mark Troll,Paul H Edelstein,Gregory M Cook,Matthew B McNeil,Lalita Ramakrishnan

{"title":"Verapamil and its metabolite norverapamil inhibit the Mycobacterium tuberculosis MmpS5L5 efflux pump to increase bedaquiline activity.","authors":"Adam J Fountain,Natalie J E Waller,Chen-Yi Cheung,William Jowsey,Michael T Chrisp,Mark Troll,Paul H Edelstein,Gregory M Cook,Matthew B McNeil,Lalita Ramakrishnan","doi":"10.1073/pnas.2426827122","DOIUrl":"https://doi.org/10.1073/pnas.2426827122","url":null,"abstract":"Bedaquiline is the cornerstone of a new regimen for the treatment of drug-resistant tuberculosis. However, its clinical use is threatened by the emergence of bedaquiline-resistant strains of Mycobacterium tuberculosis. Bedaquiline targets mycobacterial ATP synthase but the predominant route to clinical bedaquiline resistance is via upregulation of the MmpS5L5 efflux pump due to mutations that inactivate the transcriptional repressor Rv0678. Here, we show that the MmpS5L5 efflux pump reduces susceptibility to bedaquiline as well as its new, more potent derivative TBAJ-876 and other antimicrobial substrates, including clofazimine and the DprE1 inhibitors PBTZ-169 and OPC-167832. Furthermore, the increased resistance of Rv0678 mutants stems entirely from increased MmpS5L5 expression. These results highlight the potential of a pharmacological MmpS5L5 inhibitor to increase drug efficacy. Verapamil, primarily used as a calcium channel inhibitor, is known to inhibit diverse efflux pumps and to potentiate bedaquiline and clofazimine activity in M. tuberculosis. Here, we show that verapamil potentiates the activity of multiple diverse MmpS5L5 substrates. Using biochemical approaches, we demonstrate that verapamil does not exert this effect by acting as a disruptor of the protonmotive force used to power MmpS5L5, as previously proposed, suggesting that verapamil inhibits the function of the MmpS5L5 pump. Finally, norverapamil, the major verapamil metabolite, which has greatly reduced calcium channel activity, has equal potency in reducing resistance to MmpS5L5 substrates. Our findings highlight verapamil's potential for enhancing bedaquiline TB treatment, for preventing acquired resistance to bedaquiline and other MmpS5L5 substrates, while also providing the impetus to identify additional MmpS5L5 inhibitors.","PeriodicalId":20548,"journal":{"name":"Proceedings of the National Academy of Sciences of the United States of America","volume":"7 1","pages":"e2426827122"},"PeriodicalIF":11.1,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143846316","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}

引用次数: 0

Focusing a viral risk ranking tool on prediction 将病毒风险排序工具的重点放在预测上

IF 11.1 1区综合性期刊

Proceedings of the National Academy of Sciences of the United States of America Pub Date : 2025-04-17 DOI: 10.1073/pnas.2419337122

Katherine Budeski, Marc Lipsitch

{"title":"Focusing a viral risk ranking tool on prediction","authors":"Katherine Budeski, Marc Lipsitch","doi":"10.1073/pnas.2419337122","DOIUrl":"https://doi.org/10.1073/pnas.2419337122","url":null,"abstract":"Preparing to rapidly respond to emerging infectious diseases is critical. SpillOver: Viral Risk Ranking is an open-source tool developed to assess the risk of novel wildlife-origin viruses spilling over from animals to humans and spreading in human populations. Several risk factors used by the tool depend on evidence of previous zoonotic spillover itself or sustained transmission in humans. Therefore, we reanalyzed the Ranking Comparison after removing eight of the 31 risk factors that require postspillover knowledge and compared the adjusted risk rankings to the originals. The area under the receiver operating characteristic curve deteriorated from 0.94 for the original risk scores to 0.73 for the adjusted ones for predicting the classification as a human virus. We also compared the mean and SD of the risk scores for the human and non-human viruses at the risk factor level. Most excluded spillover-dependent risk factors had dissimilar means between the human and non-human virus classifications, but nonspillover-dependent risk factors frequently showed similar means between the two classifications. The original formulation of the tool depended on the inclusion of spillover-dependent risk factors to quantitatively assess the risk of zoonotic spillover for a novel virus. Future iterations of the tool should omit such risk factors and consider other nonspillover-dependent risk factors to ensure that the tool is fit for risk prediction of novel viruses.","PeriodicalId":20548,"journal":{"name":"Proceedings of the National Academy of Sciences of the United States of America","volume":"108 1","pages":""},"PeriodicalIF":11.1,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143847236","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}

引用次数: 0

Virion-associated influenza hemagglutinin clusters upon sialic acid binding visualized by cryoelectron tomography 低温电子断层扫描显示唾液酸结合上的病毒粒子相关流感血凝素簇

IF 11.1 1区综合性期刊

Proceedings of the National Academy of Sciences of the United States of America Pub Date : 2025-04-17 DOI: 10.1073/pnas.2426427122

Qiuyu J. Huang, Ryan Kim, Kangkang Song, Nikolaus Grigorieff, James B. Munro, Celia A. Schiffer, Mohan Somasundaran

{"title":"Virion-associated influenza hemagglutinin clusters upon sialic acid binding visualized by cryoelectron tomography","authors":"Qiuyu J. Huang, Ryan Kim, Kangkang Song, Nikolaus Grigorieff, James B. Munro, Celia A. Schiffer, Mohan Somasundaran","doi":"10.1073/pnas.2426427122","DOIUrl":"https://doi.org/10.1073/pnas.2426427122","url":null,"abstract":"Influenza viruses are enveloped, negative-sense single-stranded RNA viruses covered in a dense layer of glycoproteins. Hemagglutinin (HA) accounts for 80 to 90% of influenza glycoprotein and plays a role in host cell binding and membrane fusion. While previous studies have characterized structures of purified receptor-free and receptor-bound HA, the effect of receptor binding on HA organization and structure on virions remains unknown. Here, we used cryoelectron tomography to visualize influenza virions bound to a sialic acid receptor mimic. Overall, receptor binding did not result in significant changes in viral morphology; however, we observed rearrangements of HA trimer organization and orientation. Compared to the even interglycoprotein spacing of unliganded HA trimers, receptor binding promotes HA trimer clustering and the formation of a triplet of trimers. Subtomogram averaging and refinement yielded 8 to 10 Å reconstructions that allowed us to visualize specific contacts between HAs from neighboring trimers and identify molecular features that mediate clustering. Taken together, we present structural evidence that receptor binding triggers clustering of HA trimers, revealing an additional layer of HA dynamics and plasticity.","PeriodicalId":20548,"journal":{"name":"Proceedings of the National Academy of Sciences of the United States of America","volume":"134 1","pages":""},"PeriodicalIF":11.1,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143847237","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}

引用次数: 0

Receptor kinase pathway signal tuning through a nontranscriptional incoherent feedforward loop. 通过非转录非相干前馈回路调节受体激酶通路信号。

IF 11.1 1区综合性期刊

Proceedings of the National Academy of Sciences of the United States of America Pub Date : 2025-04-17 DOI: 10.1073/pnas.2420575122

Qian Wang,Yeon Hee Kang,Christian S Hardtke

{"title":"Receptor kinase pathway signal tuning through a nontranscriptional incoherent feedforward loop.","authors":"Qian Wang,Yeon Hee Kang,Christian S Hardtke","doi":"10.1073/pnas.2420575122","DOIUrl":"https://doi.org/10.1073/pnas.2420575122","url":null,"abstract":"Cellular signaling processes can elicit powerful responses and may need to be amplified to be efficient or dampened to prevent overstimulation. Therefore, they often involve autoregulatory feedbacks. Receptor kinase signaling pathways are abundant in plants, where they convey the presence of both exogenous and endogenous ligands. Among them, endogenous CLAVATA3/EMBRYO SURROUNDING REGION (CLE) peptide signaling acts in an inherently quantitative manner to determine the size of stem cell pools and direct tissue formation. The plant-specific MEMBRANE-ASSOCIATED KINASE REGULATOR (MAKR) family proteins act downstream of receptor kinases. Among the seven family members in Arabidopsis (Arabidopsis thaliana), MAKR5 conveys CLE45 signaling downstream of the receptor kinase BARELY ANY MERISTEM 3 (BAM3). Here, we show that the distinct MAKR5 mode of action can only be fully mimicked by MAKR3, suggesting functional diversification of MAKR proteins. Moreover, we find that CLE45-stimulated and BAM3-dependent MAKR5 recruitment to the plasma membrane can be triggered independent of receptor-like cytoplasmic kinases that act downstream of BAM3 and depends on membrane charge. The CLE45-BAM3-triggered enhancement of MAKR5 production and plasma membrane association is mediated by autoregulatory feedback on MAKR5 mRNA translation, for which the 5' UTR is required. At the same time, this signal amplification is dampened through CLE45-stimulated MAKR5 phosphorylation, which inactivates MAKR5, enhances its turnover, and impinges on MAKR5 mRNA levels. In summary, our results reveal a nontranscriptional incoherent feedforward loop in which receptor kinase signaling is amplified via ligand-triggered translation of a signal enhancer's mRNA yet also balanced via ligand-triggered inactivation of the signal enhancer protein.","PeriodicalId":20548,"journal":{"name":"Proceedings of the National Academy of Sciences of the United States of America","volume":"67 1","pages":"e2420575122"},"PeriodicalIF":11.1,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143846313","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}

引用次数: 0

Exotic mechanical properties enabled by countersnapping instabilities. 奇异的机械性能，使反击不稳定性。

IF 11.1 1区综合性期刊

Proceedings of the National Academy of Sciences of the United States of America Pub Date : 2025-04-17 DOI: 10.1073/pnas.2423301122

Paul Ducarme,Bart Weber,Martin van Hecke,Johannes T B Overvelde

{"title":"Exotic mechanical properties enabled by countersnapping instabilities.","authors":"Paul Ducarme,Bart Weber,Martin van Hecke,Johannes T B Overvelde","doi":"10.1073/pnas.2423301122","DOIUrl":"https://doi.org/10.1073/pnas.2423301122","url":null,"abstract":"Mechanical snapping instabilities are leveraged by natural systems, metamaterials, and devices for rapid sensing, actuation, and shape changes, as well as to absorb impact. In all current forms of snapping, shapes deform in the same direction as the exerted forces, even though there is no physical law that dictates this. Here, we realize countersnapping mechanical structures that respond in the opposite way. In contrast to regular snapping, countersnapping manifests itself in a sudden shortening transition under increasing tension or a sudden increase in tensile force under increasing extension. We design these structures by combining basic flexible building blocks that leverage geometric nonlinearities. We demonstrate experimentally that countersnapping can be employed to obtain new exotic properties, such as unidirectional stick-slip motion, switchable stiffness that does not otherwise affect the state of the system, and passive resonance avoidance. Moreover, we demonstrate that combining multiple countersnapping elements allows sequential stiffness switching for elements coupled in parallel, or instantaneous collective switching for elements in series. By expanding the repertoire of realizable elastic instabilities, our work opens routes to principles for mechanical sensing, computation, and actuation.","PeriodicalId":20548,"journal":{"name":"Proceedings of the National Academy of Sciences of the United States of America","volume":"265 1","pages":"e2423301122"},"PeriodicalIF":11.1,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143846294","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}

引用次数: 0