查看更多>>摘要：In adult gonads,disruption of somatic sexual identity leads to defective gametogenesis and infertility.However,the underlying mechanisms by which somatic signals regulate germline cells to achieve proper gametogenesis remain unclear.In our previous study,we introduced the chinmoSex Transformation(chinmoST)mutant Drosophila testis phenotype as a valuable model for investigating the mechanisms underlying sex maintenance.In chinmoST testes,depletion of the Janus Kinase-Signal Transducer and Activator of Transcription downstream effector Chinmo from somatic cyst stem cells(CySCs)feminizes somatic cyst cells and arrests germline differentiation.Here,we use single-cell RNA sequencing to uncover chinmoST-specific cell populations and their transcriptomic changes during sex transformation.Comparative analysis of intercellular communication networks between wild-type and chinmoST testes revealed disruptions in several soma-germline signaling pathways in chinmoST testes.Notably,the insulin signaling pathway exhibited significant enhancement in germline stem cells(GSCs).Chinmo cleavage under targets and tagmentation(CUT&Tag)assay revealed that Chinmo directly regulates two male sex determination factors,doublesex(dsx)and fruitless(fru),as well as Ecdysone-inducible gene L2(ImpL2),a negative regulator of the insulin signaling pathway.Further genetic manipulations confirmed that the impaired gametogenesis observed in chinmoST testes was partly contributed by dysregulation of the insulin signaling pathway.In summary,our study demonstrates that somatic sex maintenance promotes normal spermatogenesis through Chinmo-mediated conserved sex determination and the insulin signaling pathway.Our work offers new insights into the complex mechanisms of somatic stem cell sex maintenance and soma-germline communication at the single-cell level.Additionally,our discoveries highlight the potential significance of stem cell sex instability as a novel mechanism contributing to testicular tumorigenesis.
查看更多>>摘要：The unprecedented surge in global methane levels has raised global concerns in recent years,casting a spotlight on China as a pivotal emitter.China has taken several actions to curb the methane emissions,but their effects remain unclear.Here,we developed the Global ObservatioN-based system for monitoring Greenhouse GAses for methane(GONGGA-CH4)and assimilate GOSAT XCH4 observations to assess changes in China's methane emissions.We find the average rate of increase in China's methane emissions(0.1±0.3 Tg CH4 yr-2)during 2016-2021 slowed down compared to the preceding years(2011-2015)(0.9±0.5 Tg CH4 yr-2),in contrast to the concurrent acceleration of global methane emissions.As a result,the contribution of China to global methane emissions dropped significantly.Notably,the slowdown of China's methane emission is mainly attributable to a reduction in biogenic emissions from wetlands and agriculture,associated with the drying trend in South China and the transition from double-season to single-season rice cropping,while fossil fuel emissions are still increasing.Our results suggest that GONGGA-CH4 provides the opportunity for independent assessment of China's methane emissions from an atmospheric perspective,providing insights into the implementation of methane-related policies that align with its ambitious climate objectives.
查看更多>>摘要：Swarming,as a special form of mating aggregation,is most noteworthy in insects of the orders Ephemeroptera,Diptera,and Trichoptera.Swarming in extant trichopterans is well understood in terms of sex composition,specific mating behaviors,and functional morphological specializations of adults,but an exploration of the evolution of such aggregative behaviors is hampered by the dearth of available examples from the fossil record as well as the ability to reliably distinguish the few gatherings as the result of swarming relative to other taphonomic or behavioral factors.Herein we describe five new fossil species of caddisflies preserved in mid-Cretaceous amber from Myanmar,all preserved as large aggregations.Monospecific aggregations of these five new species can be positively identified as swarms based on morphological traits of wing shape,as well as the presence of particular forms of sexual dimorphism.Results of a phylogenetic reconstruction of both molecular and morphological data as well as ancestral-trait reconstructions and tip-dating analyses indicate that swarming was likely present in the Triassic as a feature of the trichopteran groundplan.Since most Mesozoic insectivorous predators were diurnal based on morphological evidence,largely nocturnal caddisflies would have been freed from such pressures.The phylogeny also shows a correlation between the rise of nocturnal bat predators from the Paleocene or early Eocene and the repeated loss of swarming from various clades of caddisflies,revealing the potential impact of bat predation on reshaping the behavioral landscape of Trichoptera during the Cenozoic.
查看更多>>摘要：An increase in atmospheric pO2 has been proposed as a trigger for the Cambrian Explosion at～539-514 Ma but the mechanistic linkage remains unclear.To gain insights into marine habitability for the Cambrian Explosion,we analysed excess Ba contents(Baexcess)and isotope compositions(δ138Baexcess)of～521-Myr-old metalliferous black shales in South China.The δ138Baexcess values vary within a large range and show a negative logarithmic correlation with Baexcess,suggesting a major(＞99％)drawdown of oceanic Ba inventory via barite precipitation.Spatial variations in Baexcess and δ138Baexcess indicate that Ba removal was driven by sulfate availability that was ultimately derived from the upwelling of deep seawaters.Global oceanic oxygenation across the Ediacaran-Cambrian transition may have increased the sulfate reservoir via oxidation of sulfide and concurrently decreased the Ba reservoir by barite precipitation.The removal of both H2S and Ba that are deleterious to animals could have improved marine habitability for early animals.
查看更多>>摘要：Whilst the 1.1 Ga North American Midcontinent Rift(MCR)system is formed in association with the Keweenaw mantle plume,the absence of a northern third rift arm or aulacogen(a general characteristic of mantle plumes)has previously not been well understood.To help clarify this unusual plume-rift relationship and to better establish the region affected by the Keweenaw mantle plume,we present the first electrical resistivity model of the MCR derived from 3D inversion of EarthScope USArray and Lithoprobe magnetotelluric(MT)data,extending northwards into the Archean Superior Province.Our model shows a prominent highly conductive anomaly trending NW-SE at the base ofWestern Superior's cratonic lithospheric mantle,cross-cutting and extending for over 300 km on both sides of the western rift branch.We propose that this anomaly reflects the ancient signature of a plume trail,resulting from metasomatism and/or partial melting of the sulfide-rich basal lithospheric mantle during impingement of the Keweenaw mantle plume.
查看更多>>摘要：Flexible multiplexing chips that permit reconfigurable multidimensional channel utilization are indispensable for revolutionary 6G terahertz communications,but the insufficient manipulation capability of terahertz waves prevents their practical implementation.Herein,we propose the first experimental demonstration of a flexible multiplexing chip for terahertz communication by revealing the unique mechanism of topological phase(TP)transition and perseveration in a heterogeneously coupled bilayer valley Hall topological photonic system.The synthetic and individual TPs operated in the coupled and decoupled states enable controllable on-chip modular TP transitions and subchannel switching.Two time-frequency interleaved subchannels support 10-and 12-Gbit/s QAM-16 high-speed data streams along corresponding paths over carriers of 120 and 130 GHz with 2.5-and 3-GHz bandwidths,respectively.This work unlocks interlayer heterogeneous TPs for inspiring ingenious on-chip terahertz-wave regulation,allowing functionality-reconfigurable,compactly integrated and CMOS-compatible chips.
查看更多>>摘要：The magnetic correlations at the superconductor/ferromagnet(S/F)interfaces play a crucial role in realizing dissipation-less spin-based logic and memory technologies,such as triplet-supercurrent spin-valves and'π'Josephson junctions.Here we report the observation of an induced large magnetic moment at high-quality nitride S/F interfaces.Using polarized neutron reflectometry and DC SQUID measurements,we quantitatively determined the magnetization profile of the S/F bilayer and confirmed that the induced magnetic moment in the adjacent superconductor only exists below TC.Interestingly,the direction of the induced moment in the superconductors was unexpectedly parallel to that in the ferromagnet,which contrasts with earlier findings in S/F heterostructures based on metals or oxides.First-principles calculations verified that the unusual interfacial spin texture observed in our study was caused by the Heisenberg direct exchange coupling with constant J～4.28 meV through d-orbital overlapping and severe charge transfer across the interfaces.Our work establishes an incisive experimental probe for understanding the magnetic proximity behavior at S/F interfaces and provides a prototype epitaxial'building block'for superconducting spintronics.
查看更多>>摘要：Superconducting infinite-layer(IL)nickelates offer a new platform for investigating the long-standing problem of high-temperature superconductivity.Many models were proposed to understand the superconducting mechanism of nickelates based on the calculated electronic structure,and the multiple Fermi surfaces and multiple orbitals involved create complications and controversial conclusions.Over the past five years,the lack of direct measurements of the electronic structure has hindered the understanding of nickelate superconductors.Here we fill this gap by directly resolving the electronic structures of the parent compound LaNiO2 and superconducting La0.8Ca0.2NiO2 using angle-resolved photoemission spectroscopy.We find that their Fermi surfaces consist of a quasi-2D hole pocket and a 3D electron pocket at the Brillouin zone corner,whose volumes change upon Ca doping.The Fermi surface topology and band dispersion of the hole pocket closely resemble those observed in hole-doped cuprates.However,the cuprate-like band exhibits significantly higher hole doping in superconducting La0.8Ca0.2NiO2 compared to superconducting cuprates,highlighting the disparities in the electronic states of the superconducting phase.Our observations highlight the novel aspects of the IL nickelates,and pave the way toward the microscopic understanding of the IL nickelate family and its superconductivity.
查看更多>>摘要：Reproducing the outstanding selectivity achieved by biological ion channels in artificial channel systems can revolutionize applications ranging from membrane filtration to single-molecule sensing technologies,but achieving this goal remains a challenge.Herein,inspired by the selectivity filter structure of the KcsA potassium channel,we propose a design of biomimetic potassium nanochannels by functionalizing the wall of carbon nanotubes with an array of arranged carbonyl oxygen atoms.Our extensive molecular dynamics simulations show that the biomimetic nanochannel exhibits a high K+permeation rate along with a high K+/Na+selectivity ratio.The free energy calculations suggest that the low Na+permeability is the result of the higher energy barrier for Na+than K+at the channel entrance and ion binding sites.In addition,reducing the number of ion binding sites leads to an increase in the permeation rate but a decrease in selectivity.These findings not only hold promise for the design of high-performance membranes but also help understand the mechanism of selective ion transport in biological ion channels.
查看更多>>摘要：Periodontitis involves hyperactivated stromal cells that recruit immune cells,exacerbating inflammation.This study presents an ATP-responsive metal-organic framework(Mg/Zn-MOF)designed for periodontitis treatment,utilizing ion interference to modulate immune responses and prevent tissue destruction.Addressing the challenges of synergistic ion effects and targeted delivery faced by traditional immunomodulatory nanomaterials,the Mg/Zn-MOF system is activated by extracellular ATP-a pivotal molecule in periodontitis pathology-ensuring targeted ion release.Magnesium and zinc ions released from the framework synergistically inhibit membrane pore formation by attenuating Gasdermin D(GSDMD)expression and activation.This action curtails pyroptosis,lactate dehydrogenase and IL-1β release,thwarting the onset of inflammatory cascades.Mechanistically,Mg/Zn-MOF intervenes in both the NLRP3/Caspase-1/GSDMD and Caspase-ll/GSDMD pathways to mitigate pyroptosis.In vivo assessments confirm its effectiveness in diminishing inflammatory cell infiltration and preserving collagen integrity,thereby safeguarding against periodontal tissue damage and bone loss.This investigation highlights the promise of ion-interference strategies in periodontitis immunotherapy,representing a significant stride in developing targeted therapeutic approaches.
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