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The Cambrian radiation of euarthropods can be attributed to an adaptable body plan. Sophisticated brains and specialized feeding appendages, which are elaborations of serially repeated organ systems and jointed appendages, underpin the dominance of Euarthropoda in a broad suite of ecological settings. The origin of the euarthropod body plan from a grade of vermiform taxa with hydrostatic lobopodous appendages ('lobopodian worms')^1,2 is founded on data from Burgess Shale-type fossils. However, the compaction associated with such preservation obscures internal anatomy^3-6. Phosphatized microfossils provide a complementary three-dimensional perspective on early crown group euarthropods⁷, but few lobopodians^8,9. Here we describe the internal and external anatomy of a three-dimensionally preserved euarthropod larva with lobopods, midgut glands and a sophisticated head. The architecture of the nervous system informs the early configuration of the euarthropod brain and its associated appendages and sensory organs, clarifying homologies across Panarthropoda. The deep evolutionary position of Youti yuanshi gen. et sp. nov. informs the sequence of character acquisition during arthropod evolution, demonstrating a deep origin of sophisticated haemolymph circulatory systems, and illuminating the internal anatomical changes that propelled the rise and diversification of this enduringly successful group.

Birds, bats and many insects can tuck their wings against their bodies when at rest and deploy them to power flight. Whereas birds and bats use well-developed pectoral and wing muscles^1,2, how insects control their wing deployment and retraction remains unclear because this varies among insect species. Beetles (Coleoptera) display one of the most complex mechanisms. In rhinoceros beetles, Allomyrina dichotoma, wing deployment is initiated by complete release of the elytra and partial release of the hindwings at their bases. Subsequently, the beetle starts flapping, elevates the hindwing bases and unfolds the hindwing tips in an origami-like fashion. Although the origami-like fold has been extensively explored^3-8, limited attention has been given to the hindwing base movements, which are believed to be driven by the thoracic muscles^5,9-11. Here we demonstrate that rhinoceros beetles can effortlessly deploy their hindwings without necessitating muscular activity. We show that opening the elytra triggers a spring-like partial release of the hindwings from the body, allowing the clearance needed for the subsequent flapping motion that brings the hindwings into the flight position. After flight, the beetle can use the elytra to push the hindwings back into the resting position, further strengthening the hypothesis of passive deployment. We validated the hypothesis using a flapping microrobot that passively deployed its wings for stable, controlled flight and retracted them neatly upon landing, demonstrating a simple, yet effective, approach to the design of insect-like flying micromachines.

Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels¹ are essential for pacemaking activity and neural signalling^2,3. Drugs inhibiting HCN1 are promising candidates for management of neuropathic pain⁴ and epileptic seizures⁵. The general anaesthetic propofol (2,6-di-iso-propylphenol) is a known HCN1 allosteric inhibitor⁶ with unknown structural basis. Here, using single-particle cryo-electron microscopy and electrophysiology, we show that propofol inhibits HCN1 by binding to a mechanistic hotspot in a groove between the S5 and S6 transmembrane helices. We found that propofol restored voltage-dependent closing in two HCN1 epilepsy-associated polymorphisms that act by destabilizing the channel closed state: M305L, located in the propofol-binding site in S5, and D401H in S6 (refs. ^7,8). To understand the mechanism of propofol inhibition and restoration of voltage-gating, we tracked voltage-sensor movement in spHCN channels and found that propofol inhibition is independent of voltage-sensor conformational changes. Mutations at the homologous methionine in spHCN and an adjacent conserved phenylalanine in S6 similarly destabilize closing without disrupting voltage-sensor movements, indicating that voltage-dependent closure requires this interface intact. We propose a model for voltage-dependent gating in which propofol stabilizes coupling between the voltage sensor and pore at this conserved methionine-phenylalanine interface in HCN channels. These findings unlock potential exploitation of this site to design specific drugs targeting HCN channelopathies.

The global retreat of glaciers is dramatically altering mountain and high-latitude landscapes, with new ecosystems developing from apparently barren substrates^1-4. The study of these emerging ecosystems is critical to understanding how climate change interacts with microhabitat and biotic communities and determines the future of ice-free terrains^1,5. Here, using a comprehensive characterization of ecosystems (soil properties, microclimate, productivity and biodiversity by environmental DNA metabarcoding⁶) across 46 proglacial landscapes worldwide, we found that all the environmental properties change with time since glaciers retreated, and that temperature modulates the accumulation of soil nutrients. The richness of bacteria, fungi, plants and animals increases with time since deglaciation, but their temporal patterns differ. Microorganisms colonized most rapidly in the first decades after glacier retreat, whereas most macroorganisms took longer. Increased habitat suitability, growing complexity of biotic interactions and temporal colonization all contribute to the increase in biodiversity over time. These processes also modify community composition for all the groups of organisms. Plant communities show positive links with all other biodiversity components and have a key role in ecosystem development. These unifying patterns provide new insights into the early dynamics of deglaciated terrains and highlight the need for integrated surveillance of their multiple environmental properties⁵.

Active basaltic eruptions enable time-series analysis of geochemical and geophysical properties, providing constraints on mantle composition and eruption processes^1-4. The continuing Fagradalsfjall and Sundhnúkur fires on Iceland's Reykjanes Peninsula, beginning in 2021, enable such an approach^5,6. Earliest lavas of this volcanic episode have been interpreted to exclusively reflect a change from shallow to deeper mantle source processes⁷. Here we show using osmium (Os) isotopes that the 2021 Fagradalsfjall lavas are both fractionally crystallized and strongly crustally contaminated, probably by mid-ocean-ridge gabbros and older basalts underlying the Reykjanes Peninsula. Earliest eruptive products (¹⁸⁷Os/¹⁸⁸Os ≤ 0.188, platinum (Pt)/iridium (Ir) ≤ 76) are highly anomalous for Icelandic lavas or global oceanic basalts and Os isotope ratios remain elevated throughout the 2021 eruption, indicating a continued but diluted presence of contaminants. The 2022 lavas show no evidence for contamination (¹⁸⁷Os/¹⁸⁸Os = 0.131, Pt/Ir = 30), being typical of Icelandic basalts (0.132 ± 0.007). Initiation of the Fagradalsfjall Fires in 2021 involved pre-eruptive stalling, fractional crystallization and crustal assimilation of earliest lavas. An established magmatic conduit system in 2022 enabled efficient magma transit to the surface without crustal assimilation.

Nasal vaccination elicits a humoral immune response that provides protection from airborne pathogens¹, yet the origins and specific immune niches of antigen-specific IgA-secreting cells in the upper airways are unclear². Here we define nasal glandular acinar structures and the turbinates as immunological niches that recruit IgA-secreting plasma cells from the nasal-associated lymphoid tissues (NALTs)³. Using intact organ imaging, we demonstrate that nasal vaccination induces B cell expansion in the subepithelial dome of the NALT, followed by invasion into commensal-bacteria-driven chronic germinal centres in a T cell-dependent manner. Initiation of the germinal centre response in the NALT requires pre-expansion of antigen-specific T cells, which interact with cognate B cells in interfollicular regions. NALT ablation and blockade of PSGL-1, which mediates interactions with endothelial cell selectins, demonstrated that NALT-derived IgA-expressing B cells home to the turbinate region through the circulation, where they are positioned primarily around glandular acinar structures. CCL28 expression was increased in the turbinates in response to vaccination and promoted homing of IgA⁺ B cells to this site. Thus, in response to nasal vaccination, the glandular acini and turbinates provide immunological niches that host NALT-derived IgA-secreting cells. These cellular events could be manipulated in vaccine design or in the treatment of upper airway allergic responses.