Current Biology最新文献

{"title":"Novel off-context experience constrains hippocampal representational drift.","authors":"Gal Elyasaf, Alon Rubin, Yaniv Ziv","doi":"10.1016/j.cub.2024.10.027","DOIUrl":"10.1016/j.cub.2024.10.027","url":null,"abstract":"<p><p>The hippocampus forms unique neural representations for distinct experiences, supporting the formation of different memories.¹^,²^,³^,⁴^,⁵^,⁶ Hippocampal representations gradually change over time as animals repeatedly visit the same familiar environment (\"representational drift\").⁷^,⁸^,⁹^,¹⁰^,¹¹^,¹² Such drift has also been observed in other brain areas, such as the parietal,¹³^,¹⁴ visual,¹⁵^,¹⁶^,¹⁷ auditory,¹⁸^,¹⁹ and olfactory²⁰ cortices. While the underlying mechanisms of representational drift remain unclear, a leading hypothesis suggests that it results from ongoing learning processes.²⁰^,²¹^,²² According to this hypothesis, because the brain uses the same neural substrates to support multiple distinct representations, learning of novel stimuli or environments leads to changes in the neuronal representation of a familiar one. If this is true, we would expect drift in a given environment to increase following new experiences in other, unrelated environments (i.e., off-context experiences). To test this hypothesis, we longitudinally recorded large populations of hippocampal neurons in mice while they repeatedly visited a familiar linear track over weeks. We introduced off-context experiences by placing mice in a novel environment for 1 h after each visit to the familiar track. Contrary to our expectations, these novel episodes decreased place cells' representational drift. Our findings are consistent with a model in which representations of distinct memories occupy different areas within the neuronal activity space, and the drift of each of them within that space is constrained by the area occupied by the others.</p>","PeriodicalId":11359,"journal":{"name":"Current Biology","volume":" ","pages":"5769-5773.e3"},"PeriodicalIF":8.1,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142681158","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Palaeontology: Walking with pterosaurs.","authors":"David M Martill","doi":"10.1016/j.cub.2024.10.066","DOIUrl":"https://doi.org/10.1016/j.cub.2024.10.066","url":null,"abstract":"<p><p>Pterosaurs, iconic flying reptiles of the Mesozoic, walked on all fours. A new study has analysed their hand and foot anatomy and how it enabled the walking lifestyle that may have been the foundation of their attaining gigantic sizes.</p>","PeriodicalId":11359,"journal":{"name":"Current Biology","volume":"34 24","pages":"R1232-R1234"},"PeriodicalIF":8.1,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142845842","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Doublecortin reinforces microtubules to promote growth cone advance in soft environments.","authors":"Alessandro Dema, Rabab A Charafeddine, Jeffrey van Haren, Shima Rahgozar, Giulia Viola, Kyle A Jacobs, Matthew L Kutys, Torsten Wittmann","doi":"10.1016/j.cub.2024.10.063","DOIUrl":"10.1016/j.cub.2024.10.063","url":null,"abstract":"<p><p>Doublecortin (DCX) is a microtubule (MT)-associated protein in immature neurons. DCX is essential for early brain development,¹ and DCX mutations account for nearly a quarter of all cases of lissencephaly-spectrum brain malformations²^,³ that arise from a neuronal migration failure through the developing cortex.⁴ By analyzing pathogenic DCX missense mutations in non-neuronal cells, we show that disruption of MT binding is central to DCX pathology. In human-induced pluripotent stem cell (hiPSC)-derived cortical i³Neurons, genome edited to express DCX-mEmerald from the endogenous locus, DCX-MT interactions polarize very early during neuron morphogenesis. DCX interacts with MTs through two conserved DCX domains⁵^,⁶ that bind between protofilaments and adjacent tubulin dimers,⁷ a site that changes conformation during guanosine triphosphate (GTP) hydrolysis.⁸ Consequently and consistent with our previous results,⁵ DCX specifically binds straight growth cone MTs and is excluded from the GTP/guanosine diphosphate (GDP)-inorganic phosphate (Pi) cap recognized by end-binding proteins (EBs). Comparing MT-bound DCX fluorescence to mEmerald-tagged nanocage standards, we measure approximately one hundred DCX molecules per micrometer growth cone MT. DCX is required for i³Neuron growth cone advance in soft microenvironments that mimic the viscoelasticity of brain tissue, and using high-resolution traction force microscopy, we find that growth cones produce comparatively small and transient traction forces. Given our finding that DCX stabilizes MTs in the growth cone periphery by inhibiting MT depolymerization, we propose that DCX contributes to growth cone biomechanics and reinforces the growth cone cytoskeleton to counteract actomyosin-generated contractile forces in soft physiological environments in which weak and transient adhesion-mediated traction may be insufficient for productive growth cone advance.</p>","PeriodicalId":11359,"journal":{"name":"Current Biology","volume":" ","pages":"5822-5832.e5"},"PeriodicalIF":8.1,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11740832/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142767404","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Biochemically plausible models of habituation for single-cell learning.","authors":"Lina Eckert, Maria Sol Vidal-Saez, Ziyuan Zhao, Jordi Garcia-Ojalvo, Rosa Martinez-Corral, Jeremy Gunawardena","doi":"10.1016/j.cub.2024.10.041","DOIUrl":"10.1016/j.cub.2024.10.041","url":null,"abstract":"<p><p>The ability to learn is typically attributed to animals with brains. However, the apparently simplest form of learning, habituation, in which a steadily decreasing response is exhibited to a repeated stimulus, is found not only in animals but also in single-cell organisms and individual mammalian cells. Habituation has been codified from studies in both invertebrate and vertebrate animals as having ten characteristic hallmarks, seven of which involve a single stimulus. Here, we show by mathematical modeling that simple molecular networks, based on plausible biochemistry with common motifs of negative feedback and incoherent feedforward, can robustly exhibit all single-stimulus hallmarks. The models reveal how the hallmarks arise from underlying properties of timescale separation and reversal behavior of memory variables, and they reconcile opposing views of frequency and intensity sensitivity expressed within the neuroscience and cognitive science traditions. Our results suggest that individual cells may exhibit habituation behavior as rich as that which has been codified in multi-cellular animals with central nervous systems and that the relative simplicity of the biomolecular level may enhance our understanding of the mechanisms of learning.</p>","PeriodicalId":11359,"journal":{"name":"Current Biology","volume":" ","pages":"5646-5658.e3"},"PeriodicalIF":8.1,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142681137","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development: Turing mechanics.","authors":"Naoya Hino, Carolina Camelo, Carl-Philipp Heisenberg","doi":"10.1016/j.cub.2024.10.065","DOIUrl":"https://doi.org/10.1016/j.cub.2024.10.065","url":null,"abstract":"<p><p>Embryo axis formation begins with the localized expression of biochemical signals, which organize cell movements and determine cell fate. A quail study finds that tissue contraction and resulting long-range changes in tissue tension restrict the area where these biochemical signals are expressed.</p>","PeriodicalId":11359,"journal":{"name":"Current Biology","volume":"34 24","pages":"R1230-R1232"},"PeriodicalIF":8.1,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142846193","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Lungfishes.","authors":"Alice Clement","doi":"10.1016/j.cub.2024.09.010","DOIUrl":"https://doi.org/10.1016/j.cub.2024.09.010","url":null,"abstract":"<p><p>Alice Clement introduces the lungfishes, a group of sarcopterygian fishes that uses lungs to breathe and is the living sister group to tetrapod vertebrates.</p>","PeriodicalId":11359,"journal":{"name":"Current Biology","volume":"34 24","pages":"R1214-R1215"},"PeriodicalIF":8.1,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142846199","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Form, function, and evolutionary origins of architectural symmetry in honey bee nests.","authors":"Michael L Smith, Peter R Marting, Claire S Bailey, Bajaree Chuttong, Erica R Maul, Roberto Molinari, P Prathibha, Ethan B Rowe, Maritza R Spott, Benjamin Koger","doi":"10.1016/j.cub.2024.10.022","DOIUrl":"10.1016/j.cub.2024.10.022","url":null,"abstract":"<p><p>Symmetry is pervasive across the tree of life,¹^,²^,³^,⁴^,⁵ and organisms (including humans) build symmetrical structures for reproduction, locomotion, or aesthetics.⁶^,⁷^,⁸^,⁹ Symmetry, however, does not necessarily span across levels of biological organization (e.g., symmetrical body plans often have asymmetric organs).¹⁰ If and how symmetry exists in structures built by social insect collectives, where there is no blueprint or central organizer, remains an open question.¹¹ Here, we show that honey bees actively organize nest contents symmetrically on either side of their double-sided comb; 79% ± 7% of cell contents match their backside counterpart, creating a mirror image inside the nest. Experimentally restricting colonies to opposite sides of comb, we find that independent colonies will symmetrically mimic each other's nest organization. We then examine the mechanism by which independent colonies can indirectly coordinate nest symmetry, showing that 100% of colonies (n = 6) perfectly co-localize their brood nest with a randomly positioned heat source, indicating that heat drives nest site initiation and early brood production. Nest symmetry also has adaptive benefits: two-sided nests grow more quickly, rear more brood, and have a more stable thermal environment than one-sided nests do. Finally, examining the evolutionary origins, we show that symmetry persists in three-dimensional (3D) nests of Apis mellifera and across multiple Apis species, coinciding with the onset of double-sided combs, which made it possible to symmetrically stockpile nest contents. This work shows that, similar to molecular mechanisms that create symmetry in multicellular organisms, there are behavioral processes that create functional symmetry in the collective organization of animal architecture.</p>","PeriodicalId":11359,"journal":{"name":"Current Biology","volume":" ","pages":"5813-5821.e5"},"PeriodicalIF":8.1,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142603659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Plant defense metabolites influence the interaction between an insect herbivore and an entomovirus.","authors":"Jin-Yan Wang, Neng-Neng Fan, Yuan Yuan, Chris Bass, Evan Siemann, Xiang-Yun Ji, Jie-Xian Jiang, Nian-Feng Wan","doi":"10.1016/j.cub.2024.10.068","DOIUrl":"10.1016/j.cub.2024.10.068","url":null,"abstract":"<p><p>The tri-trophic interaction of plants, insect herbivores, and entomoviruses is an important topic in ecology and pest control. The susceptibility of insect herbivores to entomoviruses (e.g., nucleopolyhedroviruses) is influenced by host plants; however, the role of plant secondary metabolites in determining such susceptibility is poorly understood. Metabolomic analyses of Brassica oleracea, Glycine max, and Ipomoea aquatica plants, which differ in how they affect the susceptibility of Spodoptera exigua to nucleopolyhedroviruses among 14 plants, suggested that the plant secondary metabolites genistein, kaempferol, quercitrin, and coumarin play a role in influencing nucleopolyhedroviruses susceptibility. Subsequently, transcriptomic analysis of caterpillars, treated with nucleopolyhedroviruses alone or with one of these four phenolics, identified four genes (CYP340K4, CXE18, GSTe, and GSTe1) that were significantly downregulated by the phenolics. Functional characterization of these genes suggested that their downregulation significantly increased larval sensitivity to nucleopolyhedroviruses and altered aspects of the immune response. Our findings provide new insight into the role of plant defense metabolites in influencing the interactions between insect herbivores and entomopathogens and identify plant secondary metabolites as potential synergists of viral agents for the control of agricultural pests.</p>","PeriodicalId":11359,"journal":{"name":"Current Biology","volume":" ","pages":"5758-5768.e5"},"PeriodicalIF":8.1,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142692642","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"RNA helicases DDX3X and DDX3Y form nanometer-scale RNA-protein clusters that support catalytic activity.","authors":"Amber Yanas, Him Shweta, Michael C Owens, Kathy Fange Liu, Yale E Goldman","doi":"10.1016/j.cub.2024.10.055","DOIUrl":"10.1016/j.cub.2024.10.055","url":null,"abstract":"<p><p>DEAD-box helicases, crucial for many aspects of RNA metabolism, often contain intrinsically disordered regions (IDRs) whose functions remain unclear. Using multiparameter confocal microscopy, we reveal that sex chromosome-encoded homologous RNA helicases, DDX3X and DDX3Y, form nanometer-scale RNA-protein clusters (RPCs) that foster their catalytic activities in vitro and in cells. The IDRs are critical for the formation of these RPCs. A thorough analysis of the catalytic cycle of DDX3X and DDX3Y by ensemble biochemistry and single-molecule photon bursts in the confocal microscope showed that RNA release is a major step that differentiates the unwinding activities of DDX3X and DDX3Y. The N-terminal IDRs of DDX3X and DDX3Y are both the drivers of RPC formation and the major differentiators of their enzymatic activities. Our findings provide new insights that the nanoscale helicase RPCs may be the normal state of these helicases under non-stressed conditions that promote their RNA unwinding and might act as nucleation points for stress granule formation. This mechanism may apply broadly among other members of the DEAD-box helicase family.</p>","PeriodicalId":11359,"journal":{"name":"Current Biology","volume":" ","pages":"5714-5727.e6"},"PeriodicalIF":8.1,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142726985","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An Ediacaran bilaterian with an ecdysozoan affinity from South Australia.","authors":"Ian V Hughes, Scott D Evans, Mary L Droser","doi":"10.1016/j.cub.2024.10.030","DOIUrl":"10.1016/j.cub.2024.10.030","url":null,"abstract":"<p><p>Molecular clocks and Cambrian-derived metazoans strongly suggest a Neoproterozoic origin of many animal clades.¹^,²^,³^,⁴ However, fossil bilaterians are rare in the Ediacaran, and no definitive ecdysozoan body fossils are known from the Precambrian. Notably, the base of the Cambrian is characterized by an abundance of trace fossils attributed to priapulid worms,⁵^,⁶ suggesting that major divisions among ecdysozoan groups occurred prior to this time. This is supported by ichnofossils from the latest Ediacaran or early Cambrian left by a plausible nematoid,⁷^,⁸^,⁹ although definitively attributing this inferred behavior to crown-Nematoida remains contentious in the absence of body fossils.¹⁰ Given the high probability of the evolution of Ecdysozoa in the Proterozoic, the otherwise prolific fossil record of the Ecdysozoa, and the identification of more than 100 distinct Ediacaran genera, it is striking that no Ediacaran body fossils have been confidently assigned to this group. Here, we describe Uncus dzaugisi gen. et. sp. nov. from the Ediacara Member (South Australia), a smooth, vermiform organism with distinct curvature and anterior-posterior differentiation. The depth of relief of Uncus is unique among Ediacara fossils and consistent with a rigid outer cuticle. Ecological relationships and associated trace fossils demonstrate that Uncus was motile. Body morphology and the inferred style of movement are consistent with Nematoida, providing strong evidence for at least an ecdysozoan affinity. This validates the Precambrian origin of Ecdysozoa, reconciling a major gap between predicted patterns of animal evolution and the fossil record.⁴.</p>","PeriodicalId":11359,"journal":{"name":"Current Biology","volume":" ","pages":"5782-5788.e1"},"PeriodicalIF":8.1,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142675301","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}