PNAS nexus最新文献_第10页

Nanotubes enable intercellular communication in early-branching eukaryotes. 在早期分支真核生物中，纳米管使细胞间通信成为可能。

IF 4.8

PNAS nexus Pub Date : 2026-07-28 eCollection Date: 2026-07-01 DOI: 10.1093/pnasnexus/pgag238

Harikumar R Suma, Robert R Kay, Sandeep M Eswarappa, Pierre Stallforth

{"title":"Nanotubes enable intercellular communication in early-branching eukaryotes.","authors":"Harikumar R Suma, Robert R Kay, Sandeep M Eswarappa, Pierre Stallforth","doi":"10.1093/pnasnexus/pgag238","DOIUrl":"10.1093/pnasnexus/pgag238","url":null,"abstract":"Social amoebae, despite being unicellular organisms, exhibit multicellular phenotypes that require well-tuned inter- and intracellular communication modes. The social amoeba Dictyostelium discoideum is an excellent model to study multicellularity and metazoan cell signaling. While communication based on secreted small molecules has been described, juxtacrine connections were so far an unexplored intercellular communication mechanism in amoebae. Using fluorescence labeling and confocal microscopy, we identified de novo formation of tunneling nanotubes (TNTs) in amoebae. Live cell imaging revealed that these nanotubes are actin-rich protrusions that facilitate cargo transport by enabling membrane continuity between the connected cells. The identification of nanotubes in different amoebal species highlights the relevance of these protrusions within natural microbial communities since they act as a complementary mechanism for the transfer of essential cellular cargo. Remarkably, TNT-mediated connectivity persists under conditions that perturb cytoskeletal dynamics, indicating that nanotube-based communication is robust and adaptable. TNTs represent a novel juxtacrine communication machinery that promotes cell-to-cell communication and coordination in early eukaryotes and could play a key role in the emergence of multicellularity.","PeriodicalId":74468,"journal":{"name":"PNAS nexus","volume":"5 7","pages":"pgag238"},"PeriodicalIF":4.8,"publicationDate":"2026-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13410376/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148623038","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Life on the edge: Mesolithic population size and viability on Malta. 边缘的生活：马耳他的中石器时代人口规模和生存能力。

IF 4.8

PNAS nexus Pub Date : 2026-07-28 eCollection Date: 2026-07-01 DOI: 10.1093/pnasnexus/pgag234

James Blinkhorn, Lucy Timbrell, Matt Grove, Andrea Manica, Mario Mata-González, Huw S Groucutt, Nicholas C Vella, Eleanor M L Scerri

{"title":"Life on the edge: Mesolithic population size and viability on Malta.","authors":"James Blinkhorn, Lucy Timbrell, Matt Grove, Andrea Manica, Mario Mata-González, Huw S Groucutt, Nicholas C Vella, Eleanor M L Scerri","doi":"10.1093/pnasnexus/pgag234","DOIUrl":"10.1093/pnasnexus/pgag234","url":null,"abstract":"Recent discoveries in Malta and Tunisia provocatively point to a possible web of Mesolithic/Epipalaeolithic sea crossings, encounters, and exchanges that linked continents long before the age of the sail. Determining whether such connections were singular events or sustained episodes is therefore critical to illuminate the scale and character of early seafaring. Here, we model how patterns of sea-level change impacted land connectivity between Sicily and Malta and predict potential population sizes through time from the Last Glacial Maximum to evaluate whether Mesolithic hunter-gatherers could have persisted on Malta, or if sustained connections would have been required. To achieve this, we use reconstructions of sea-level change and modern bathymetric models to evaluate changes in land size areas and connectivity. We calculate net primary productivity values for a high-resolution paleoclimate dataset, which we translate to population density by comparisons to ethnographic datasets. Finally, we calculate changes in estimated population sizes through time for Malta and Sicily, as well as minimum distances of sea voyages. Our results show that following disconnection from Sicily, Malta would have been unable to support a viable, persistent forager population, including for the minimum 1000-year timespan of the Maltese Mesolithic record. As a result, only repeated, long-distance sea voyaging can explain the longevity of Mesolithic occupations of Malta, opening up the possibility that other south-central Mediterranean islands were reached and explaining the presence of European hunter-gatherer ancestry in North Africa.","PeriodicalId":74468,"journal":{"name":"PNAS nexus","volume":"5 7","pages":"pgag234"},"PeriodicalIF":4.8,"publicationDate":"2026-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13410373/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148622963","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Intermittent fasting rewires tissue-specific gene-transposable element regulatory networks. 间歇性禁食重新连接组织特异性基因转座元件调控网络。

IF 4.8

PNAS nexus Pub Date : 2026-07-27 eCollection Date: 2026-08-01 DOI: 10.1093/pnasnexus/pgag254

Xiangru Cheng, Yibo Fan, Xiangyuan Peng, Nishat I Tabassum, Dong-Gyu Jo, Terrance G Johns, Sureshkumar Balasubramanian, Sridevi Sureshkumar, Thiruma V Arumugam

{"title":"Intermittent fasting rewires tissue-specific gene-transposable element regulatory networks.","authors":"Xiangru Cheng, Yibo Fan, Xiangyuan Peng, Nishat I Tabassum, Dong-Gyu Jo, Terrance G Johns, Sureshkumar Balasubramanian, Sridevi Sureshkumar, Thiruma V Arumugam","doi":"10.1093/pnasnexus/pgag254","DOIUrl":"10.1093/pnasnexus/pgag254","url":null,"abstract":"Intermittent fasting (IF) is a dietary intervention known to promote systemic health benefits, yet its impact on genome-wide transcriptional regulatory networks, particularly those involving transposable elements (TEs), remains poorly understood. This study investigates the multitissue transcriptomic response to chronic IF in mice, focusing on TE regulation and its integration with host gene networks. We subjected C57BL/6 mice to 16 h of daily fasting for 4 months and performed RNA-seq on liver, skeletal muscle, and cortex tissues. Using locus-specific TE quantification, we found that IF induces profound, tissue-specific changes in TE expression, with the liver showing the strongest response (5,359 differentially expressed TEs), followed by skeletal muscle (620), while minimal changes were observed in the cortex. Integrated co-expression network analysis (WGCNA) in the liver and muscle revealed IF-responsive TEs that co-vary with nearby genes, forming distinct co-expression modules. Functional enrichment of genes proximal to co-expressed TEs within these modules highlighted clear tissue-specific regulatory programs. In the liver, the enriched terms were predominantly associated with translation and metabolism, whereas in skeletal muscle, the enriched pathways were involved in muscle contraction, mitochondrial organization, and chromatin modification. Furthermore, correlation analysis revealed strong, significant co-expression between TEs and their proximal genes within these modules, suggesting that TEs may exert potential cis-regulatory effects on adjacent genes. Taken together, our results provide a high-resolution atlas of TE regulation under IF and demonstrate that TEs are integral components of tissue-specific transcriptional networks reshaped by fasting. These findings offer new insights into how dietary interventions influence gene regulatory systems.","PeriodicalId":74468,"journal":{"name":"PNAS nexus","volume":"5 8","pages":"pgag254"},"PeriodicalIF":4.8,"publicationDate":"2026-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13436429/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148674881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Hot temperature during development alters iridescence in Morpho butterflies. 发育期的高温会改变大闪蝶的虹彩。

IF 4.8

PNAS nexus Pub Date : 2026-07-23 eCollection Date: 2026-08-01 DOI: 10.1093/pnasnexus/pgag243

Juliette J Rubin, Leo T Camino, Yanileth F López-Tacoaman, Pushkar R Wagh, Greta C Hernández Campos, W Owen McMillan

{"title":"Hot temperature during development alters iridescence in Morpho butterflies.","authors":"Juliette J Rubin, Leo T Camino, Yanileth F López-Tacoaman, Pushkar R Wagh, Greta C Hernández Campos, W Owen McMillan","doi":"10.1093/pnasnexus/pgag243","DOIUrl":"10.1093/pnasnexus/pgag243","url":null,"abstract":"Environmental temperature during critical stages of development can define the phenotype of an individual, especially for ectotherms. Color is a particularly biologically important phenotypically plastic trait but has been primarily studied in the context of pigmentary, rather than structural, coloration. In Morpho butterflies (Nymphalidae), structural coloration created by nanostructures on the wing scales leads to their striking blue iridescent effect. We reared Morpho helenor larvae and exposed the pupae to three temperature regimes during development: control tropics, temperate cool, and hot house, with hotter temperatures simulating those predicted under a future climate change scenario. We hypothesized that the hot house treatment would be the most disruptive to iridescence. In support of this hypothesis, hot conditions reduced the brightness of adult butterfly wings and altered the color profile enough that they would look different from control butterflies to bird predators and conspecifics. For certain bird perceivers, hot conditions would obliterate the iridescent effect entirely. The mechanism underlying these shifts appears to be, at least in part, driven by a decrease in the gap between nanostructures on the wing scale and consequent narrowing of the entire scale. Our study highlights the ways in which structural color is alternately vulnerable or robust to environmental temperature during development. From this work, we can glean insight into the environments that would be most supportive of iridescence in tropical butterflies and make predictions about the effects that changing climate regimes will have on the diversity of some of the earth's most dazzling organisms.","PeriodicalId":74468,"journal":{"name":"PNAS nexus","volume":"5 8","pages":"pgag243"},"PeriodicalIF":4.8,"publicationDate":"2026-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13430421/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148671467","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Finite-stage nonreciprocal thermal circulators for radiative energy harvesting: Benchmarks for isolation, termination, and etendue. 用于辐射能量收集的有限级非互反热循环器：隔离、终止和终止的基准。

IF 4.8

PNAS nexus Pub Date : 2026-07-21 eCollection Date: 2026-07-01 DOI: 10.1093/pnasnexus/pgag249

Seungwoo Lee

{"title":"Finite-stage nonreciprocal thermal circulators for radiative energy harvesting: Benchmarks for isolation, termination, and etendue.","authors":"Seungwoo Lee","doi":"10.1093/pnasnexus/pgag249","DOIUrl":"10.1093/pnasnexus/pgag249","url":null,"abstract":"Reaching the Landsberg limit for radiative energy conversion requires controlling not only spectra but also the direction in which radiative entropy is transported. We develop a finite-stage nonreciprocal thermal-circulator framework for positive illumination (solar conversion) and negative illumination (radiative-cooling work extraction). The ideal theory is expressed in terms of open-system exergy and a minimal port-network picture: a three-port circulator with a cold termination acts as a two-port thermal isolator, and cascaded isolators enforce directed adjacency between effective photon reservoirs. In response to the central practical limitation of nonreciprocal radiative cooling, emphasized recently by Liu et al. we recast the problem as a benchmark map rather than a claim of immediate device-level cooling enhancement. The reported work output values (in unit of W m-2) are hemispherical-equivalent upper envelopes; experimentally relevant output is reduced by captured free-space etendue, coupling efficiency, finite isolation ratio, finite termination temperature, atmospheric transmission, and out-of-window loss. We therefore introduce explicit sensitivity factors for isolation, termination, and captured etendue and ask how good a nonreciprocal system must be before the finite-stage advantage remains measurable. Finite-stage calculations give temperature and wavelength targets for 3-5 stages, while the practical benchmark identifies the isolation, termination, and coupling requirements needed to make those targets consequential. This formulation links ideal Landsberg-type limits to testable design requirements for nonreciprocal thermal photonics.","PeriodicalId":74468,"journal":{"name":"PNAS nexus","volume":"5 7","pages":"pgag249"},"PeriodicalIF":4.8,"publicationDate":"2026-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13419078/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148623027","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Correction to: Nudging recommendation algorithms increases news consumption and diversity on YouTube. 更正：推动推荐算法增加了YouTube上的新闻消费和多样性。

IF 4.8

PNAS nexus Pub Date : 2026-07-21 eCollection Date: 2026-07-01 DOI: 10.1093/pnasnexus/pgag241

引用次数: 0

Emphasizing society's expectations enhances charitable giving in NGO advertisements. 在公益广告中，强调社会期望能提高公益捐赠。

IF 4.8

PNAS nexus Pub Date : 2026-07-21 eCollection Date: 2026-07-01 DOI: 10.1093/pnasnexus/pgag206

Toshiko Tanaka, Tsuyoshi Nihonsugi, Masahiko Haruno

引用次数: 0

Reduced integrity in the frontal aslant tract's premotor connections is associated with dysfluency severity in stuttering. 额斜束运动前连接完整性降低与口吃的流利障碍严重程度有关。

IF 4.8

PNAS nexus Pub Date : 2026-07-17 eCollection Date: 2026-07-01 DOI: 10.1093/pnasnexus/pgag245

Maëva Michon, Fabrice Hirsch, Ivana Didirková, Davide Giampiccolo, Marie-Claude Monfrais-Pfauwadel, Anne-Laure Lemaitre, Jérémy Deverdun, Emmanuelle Lebars, Guillaume Herbet

{"title":"Reduced integrity in the frontal aslant tract's premotor connections is associated with dysfluency severity in stuttering.","authors":"Maëva Michon, Fabrice Hirsch, Ivana Didirková, Davide Giampiccolo, Marie-Claude Monfrais-Pfauwadel, Anne-Laure Lemaitre, Jérémy Deverdun, Emmanuelle Lebars, Guillaume Herbet","doi":"10.1093/pnasnexus/pgag245","DOIUrl":"10.1093/pnasnexus/pgag245","url":null,"abstract":"Stuttering is a neurodevelopmental disorder marked by impaired speech production and substantial interindividual variability in symptom severity. Although neuroimaging studies have identified abnormalities in the basal ganglia-thalamocortical circuitry, the specific white matter pathways that underpin dysfluent speech production remain poorly understood. Here, we focus on the frontal aslant tract (FAT), a dorsoventral intralobar tract connecting the superior and inferior frontal cortices and proposed to support both cognitive and motor functions. Using diffusion MRI, we first compared the quantitative anisotropy of the FAT and relevant control tracts in individuals who stutter (n = 30, mean age = 35.67, SD = 13.03) and fluent speakers (n = 22, mean age = 35.64, SD = 10.87) and observed no significant group-level differences in either hemisphere. To delineate the role of FAT subbundles in speech dysfluency, we then segmented the tract at its dorsal and ventral cortical terminations and assessed their relationships with stuttering severity (Stuttering Severity Instrument-Fourth Edition). We identified left FAT subbundles connecting the posteroventral frontal structures, particularly the rostroventral precentral gyrus and, to a lesser extent, the pars opercularis to a dorsal prefrontal region whose integrity predicts stuttering severity. The left-lateralized nature of these associations suggests that stuttering results, in part, from abnormal connectivity between prefrontal systems governing volitional control and the motor circuits engaged in speech production. Together, these findings refine current neurobiological models of stuttering by implicating frontofrontal white matter pathways underlying speech dysfluency and highlight a potential anatomical target for individualized therapeutic interventions.","PeriodicalId":74468,"journal":{"name":"PNAS nexus","volume":"5 7","pages":"pgag245"},"PeriodicalIF":4.8,"publicationDate":"2026-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13398998/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148586059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Memorizing the future: Encoding anticipated interactions enhances human memory for dynamic stimuli. 记忆未来：对预期的相互作用进行编码可以增强人类对动态刺激的记忆。

IF 4.8

PNAS nexus Pub Date : 2026-07-16 eCollection Date: 2026-07-01 DOI: 10.1093/pnasnexus/pgag244

Gonzalo Aparicio-Rodríguez, Daniel Ruiz Navalón, Paloma Manubens, Abel Sánchez-Jiménez, Carlos Calvo-Tapia, José Antonio Villacorta-Atienza

{"title":"Memorizing the future: Encoding anticipated interactions enhances human memory for dynamic stimuli.","authors":"Gonzalo Aparicio-Rodríguez, Daniel Ruiz Navalón, Paloma Manubens, Abel Sánchez-Jiménez, Carlos Calvo-Tapia, José Antonio Villacorta-Atienza","doi":"10.1093/pnasnexus/pgag244","DOIUrl":"10.1093/pnasnexus/pgag244","url":null,"abstract":"Survival in nature requires responding to rapidly changing situations, where memory is crucial for fast and reliable decision-making. This work explores human memory modulation under the hypothesis that in dynamic scenarios critical information is encoded as static maps of future interactions. Results show that dynamic stimuli containing future interactions are recalled 36% better than equivalent stimuli that do not and even 23% better than simpler dynamic stimuli. This aligns with a central prediction of the time-compaction hypothesis, suggesting that stimuli involving anticipated interactions may be more efficiently memorized and recalled because they are compatible with simplified static representations of future interactions-their maps of interactions. This effect is modulated by stimulus complexity: in simple scenarios, recall differences appear only in men, while in more complex situations, no gender bias emerges. This work reveals novel mechanisms by which memory can cope with dynamic situations, suggesting that those critical to survival-fighting, chasing, or fleeing-are preferentially remembered, enabling efficient learning and decision-making in a complex changing world.","PeriodicalId":74468,"journal":{"name":"PNAS nexus","volume":"5 7","pages":"pgag244"},"PeriodicalIF":4.8,"publicationDate":"2026-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13398999/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148586100","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Functional role of a structural water in the elevator domain of dicarboxylate transporter VcINDY. 结构水在二羧酸转运体VcINDY升降机结构中的功能作用。

IF 4.8

PNAS nexus Pub Date : 2026-07-16 eCollection Date: 2026-07-01 DOI: 10.1093/pnasnexus/pgag242

Andrew Daab, Yan Li, Jennifer J Marden, Jinmei Song, David B Sauer, Da-Neng Wang, Christopher Mulligan

{"title":"Functional role of a structural water in the elevator domain of dicarboxylate transporter VcINDY.","authors":"Andrew Daab, Yan Li, Jennifer J Marden, Jinmei Song, David B Sauer, Da-Neng Wang, Christopher Mulligan","doi":"10.1093/pnasnexus/pgag242","DOIUrl":"10.1093/pnasnexus/pgag242","url":null,"abstract":"The divalent anion sodium symporter (DASS) family mediates the uptake of Krebs cycle intermediates and sulfate and influences adiposity, insulin resistance, and metabolism in mammals. While Na+:substrate stoichiometry is known for several DASS transporters, the location of key Na+-binding sites remains elusive; important information for understanding the mechanism. In VcINDY, a bacterial DASS protein, we visualized a nonprotein cryo-electron microscopy (cryo-EM) density in the middle of the transport domain. Its size and coordination suggest that it may represent either a third Na+ ion or a structural water molecule. Using a combination of in vitro binding and transport assays, cryo-EM structural determination, and molecular dynamic simulations, we show that the density is not a Na+ ion. Instead, the data indicate that the density likely represents a structural water molecule critical for transport domain integrity. Sequence and structural similarities suggest this feature may be conserved across human DASS transporters such as NaCT and NaDC3.","PeriodicalId":74468,"journal":{"name":"PNAS nexus","volume":"5 7","pages":"pgag242"},"PeriodicalIF":4.8,"publicationDate":"2026-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13394699/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148581483","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0