Current Biology最新文献

{"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":"Genome dynamics across the evolutionary transition to endosymbiosis.","authors":"Stefanos Siozios, Pol Nadal-Jimenez, Tal Azagi, Hein Sprong, Crystal L Frost, Steven R Parratt, Graeme Taylor, Laura Brettell, Kwee Chin Liew, Larry Croft, Kayla C King, Michael A Brockhurst, Václav Hypša, Eva Novakova, Alistair C Darby, Gregory D D Hurst","doi":"10.1016/j.cub.2024.10.044","DOIUrl":"10.1016/j.cub.2024.10.044","url":null,"abstract":"<p><p>Endosymbiosis-where a microbe lives and replicates within a host-is an important contributor to organismal function that has accelerated evolutionary innovations and catalyzed the evolution of complex life. The evolutionary processes associated with transitions to endosymbiosis, however, are poorly understood. Here, we leverage the wide diversity of host-associated lifestyles of the genus Arsenophonus to reveal the complex evolutionary processes that occur during the transition to a vertically transmitted endosymbiotic lifestyle from strains maintained solely by horizontal (infectious) transmission. We compared the genomes of 38 strains spanning diverse lifestyles from horizontally transmitted pathogens to obligate interdependent endosymbionts. Among culturable strains, we observed those with vertical transmission had larger genome sizes than closely related horizontally transmitting counterparts, consistent with evolutionary innovation and the rapid gain of new functions. Increased genome size was a consequence of prophage and plasmid acquisition, including a cargo of type III effectors, alongside the concomitant loss of CRISPR-Cas genome defense systems, enabling mobile genetic element expansion. Persistent endosymbiosis was also associated with loss of type VI secretion, which we hypothesize to be a consequence of reduced microbe-microbe competition. Thereafter, the transition to endosymbiosis with strict vertical inheritance was associated with the expected relaxation of purifying selection, gene pseudogenization, metabolic degradation, and genome reduction. We argue that reduced phage predation in endosymbiotic niches drives the loss of genome defense systems driving rapid genome expansion upon the adoption of endosymbiosis and vertical transmission. This remodeling enables rapid horizontal gene transfer-mediated evolutionary innovation and precedes the reductive evolution traditionally associated with adaptation to endosymbiosis.</p>","PeriodicalId":11359,"journal":{"name":"Current Biology","volume":" ","pages":"5659-5670.e7"},"PeriodicalIF":8.1,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142643963","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":"Adaptation to visual sparsity enhances responses to isolated stimuli.","authors":"Tong Gou, Catherine A Matulis, Damon A Clark","doi":"10.1016/j.cub.2024.10.053","DOIUrl":"10.1016/j.cub.2024.10.053","url":null,"abstract":"<p><p>Sensory systems adapt their response properties to the statistics of their inputs. For instance, visual systems adapt to low-order statistics like mean and variance to encode stimuli efficiently or to facilitate specific downstream computations. However, it remains unclear how other statistical features affect sensory adaptation. Here, we explore how Drosophila's visual motion circuits adapt to stimulus sparsity, a measure of the signal's intermittency not captured by low-order statistics alone. Early visual neurons in both ON and OFF pathways alter their responses dramatically with stimulus sparsity, responding positively to both light and dark sparse stimuli but linearly to dense stimuli. These changes extend to downstream ON and OFF direction-selective neurons, which are activated by sparse stimuli of both polarities but respond with opposite signs to light and dark regions of dense stimuli. Thus, sparse stimuli activate both ON and OFF pathways, recruiting a larger fraction of the circuit and potentially enhancing the salience of isolated stimuli. Overall, our results reveal visual response properties that increase the fraction of the circuit responding to sparse, isolated stimuli.</p>","PeriodicalId":11359,"journal":{"name":"Current Biology","volume":" ","pages":"5697-5713.e8"},"PeriodicalIF":8.1,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142692625","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":"Ecdysteroid-dependent molting in tardigrades.","authors":"Shumpei Yamakawa, Andreas Hejnol","doi":"10.1016/j.cub.2024.10.054","DOIUrl":"10.1016/j.cub.2024.10.054","url":null,"abstract":"<p><p>Although molting is a defining feature of the most species-rich animal taxa-the Ecdysozoa, including arthropods, tardigrades, nematodes, and others¹^,²-its evolutionary background remains enigmatic. In pancrustaceans, such as insects and decapods, molting is regulated by the ecdysteroid (Ecd) hormone and its downstream cascade (Figure 1A, see also the text).³^,⁴^,⁵ However, whether Ecd-dependent molting predates the emergence of the arthropods and represents an ancestral machinery in ecdysozoans remains unclear. For example, involvement of the Ecd hormone in molting regulation has been suggested only in some parasitic nematodes outside of arthropods,⁶^,⁷ and insect Ecd synthesis and receptor genes are lacking in some ecysozoan lineages (Figure S1A).⁸^,⁹^,¹⁰ In this study, we investigated the role of Ecd in the molting process of the tardigrade Hypsibius exemplaris. We show that the endogenous Ecd level periodically increases during the molting cycle of H. exemplaris. The pulse treatment with exogenous Ecd induced molting, whereas an antagonist of the Ecd receptor suppressed the molting. Our spatial and temporal gene expression analysis revealed the putative regulatory organs and Ecd downstream cascades. We demonstrate that tardigrade molting is regulated by the Ecd hormone, supporting the ancestry of Ecd-dependent molting in panarthropods. Furthermore, we were able to identify the putative neural center of molting regulation in tardigrades. This region may be homologous to the neural center in the protocerebrum of pancrustaceans and represent an ancestral state of panarthropods. Together, our results suggest that Ecd-dependent molting evolved in the early-late Ediacaran, 22-76 million years earlier than previously suggested.¹¹.</p>","PeriodicalId":11359,"journal":{"name":"Current Biology","volume":" ","pages":"5804-5812.e4"},"PeriodicalIF":8.1,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142681138","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":"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":"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":"","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":"","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":"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":"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}