Proteostasis of proteins with intrinsically disordered regions (IDRs) is of particular importance to the development and function of the central nervous system (CNS). The conserved ZSWIM8 ubiquitin ligase, an essential regulator of mammalian brain development, is known to target IDR proteins involved in neuronal cell migration. Here we show that ZSWIM8 is also indispensable for oligodendrocyte maturation and myelination in the CNS. Loss of ZSWIM8 in the brain causes gross accumulation of IDR-rich proteins including many RNA-binding proteins (RBPs). Substrate recognition by ZSWIM8 requires its own IDRs, while ZSWIM8-mediated ubiquitination of AGO2 also depends on microRNA binding. AGO2 stabilization in ZSWIM8-null tissues disrupts target-directed microRNA degradation (TDMD) of MiR7, leading to altered gene expressions and myelination defects in vivo. Together, these results not only establish ZSWIM8 as a versatile regulator of IDR proteins but also highlight the crucial roles of RBP/miRNA homeostasis in oligodendrocyte development.
The insect pretarsi are the sites of direct contact with the proximal environment. Aspects of pretarsal structures have been described in the literature. Comprehensive and detailed histological analyses of the pretarsal composition depicting the interaction of the different types of outside and inside tissues in insects are, however, anecdotal. Here, we present a tri-dimensional image of the tarsal ends of the housefly Musca domestica at the ultrastructural level using focussed-ion beam combined with scanning electron microscopy. In particular, we find that the different functional elements of the pretarsus have distinct cuticle thicknesses. In detail, the cuticle is thin at the joint to the fifth tarsomere, thickens in the dorsal claws and the ventral unguitractor plate; the ventral pulvilli, again, have a rather thin cuticle with the basis of their tenent acanthae (adhesive cuticle protrusions) arranged like roof tiles before the shafts protrude forming the adhesive acanthal cushion. Inside the cuticular tube, we discerned a composite filament with the distal end of a large gland, paired bundles of axons projecting into the claws but not the pulvilli and a tracheal tube. These elements are associated with the cuticular unguitractor tendon in the fifth tarsal subsegment that bridges to the external cuticle via a possibly flexible membranous cuticle. These data will serve in studying the pretarsal function regarding its interaction with the environment associated with its different structures in molecular and reverse genetic experiments.
Soil acidification disrupts the structure and function of soil microbiomes, resulting in increased vulnerability to soil-borne pathogens. While the link between soil acidification and disease susceptibility is well-established, the mechanisms underlying the suppression of plant defense remain poorly understood. In this study, we found that soil acidification perturbed the co-evolved assembly process of endophytic microbiomes in watermelon roots, leading to the collapse of a critical microbe-metabolite-host defense axis essential for resistance against Fusarium oxysporum f. sp. niveum (FON). Integrated field surveys and multi-omics analyses revealed that acidification-induced dysbiosis in the root endophytic microbiomes, characterized by the depletion of keystone Pseudomonas species (Pseudomonadaceae), strongly correlated with increased Fusarium wilt incidence. Central to this interaction was citrulline, a metabolite produced by root Pseudomonas endophytes that functioned as a symbiotic effector promoting bacterial colonization and a defense modulator inhibiting FON-induced oxidative burst. Disruption of citrulline biosynthesis abolished these protective effects, whereas exogenous citrulline application restored disease resistance. These findings underscored the role of root endophyte-derived citrulline in sustaining microbial fitness and plant defense, revealing a tripartite interaction impacted by soil acidification. Collectively, this study provides insights for developing microbiome-based strategies to enhance sustainable crop protection in degraded agroecosystems.
This study presents a comprehensive three-dimensional anatomical atlas of the adult Nilaparvata lugens using micro-CT and FIB-SEM. The reconstructions reveal the spatial organization of the flight muscle system, digestive tract, reproductive organs, and nervous system. The indirect flight muscles, including dorsal longitudinal and dorsoventral muscles, are structurally similar between sexes but show size differences in certain components. The female reproductive system occupies most of the abdominal cavity, reflecting high fecundity, while the male reproductive system features a specialized ejaculatory duct associated with muscular control. Notably, the genital coupling during copulation involves a sophisticated interlocking structure, ensuring stable alignment and preventing separation. These structural insights offer a holistic framework for understanding dispersal and reproduction in N. lugens, with implications for developing novel pest management strategies.
Pyroptosis, a pro-inflammatory form of programmed cell death, is crucial for host defense against pathogens and danger signals. Proteolytic cleavage of gasdermin proteins B-E (GSDMB-GSDME) is well established as a trigger for pyroptosis, but the intracellular activation mechanism of GSDMA remains elusive. Here, we demonstrate that severe starvation induces pyroptosis through phosphorylation-induced activation of GSDMA. Nutrient stresses stimulate GSDMA activation via phosphorylation mediated by Unc-51-like autophagy-activating kinase 1 (ULK1). Phosphorylation of Ser353 on human GSDMA by ULK1 or the phospho-mimetic Ser353Asp mutant of GSDMA liberates GSDMA from auto-inhibition, facilitating its membrane targeting and initiation of pyroptosis. To further validate the significance of GSDMA phosphorylation, we generated a constitutively active mutant Ser354Asp of mouse Gsdma, which induced skin inflammation and hyperplasia in mice, reminiscent of phenotypes with activated Gsdma. This study uncovers phosphorylation of GSDMA as a mechanism underlying pyroptosis initiation and cellular response to nutrient stress.
Frankliniella occidentalis (western flower thrips) is a globally destructive pest causing major crop losses via oviposition, feeding, and plant virus transmission. Previous work has focused on its reproductive physiology and behavior, but comprehensive 3D structural knowledge remains limited. We used volume electron microscopy to achieve nanoscale 3D visualization of the reproductive systems in both sexes, providing the first high-resolution, in situ reconstruction, and establishing a new anatomical framework for insect reproductive physiology. Males exhibit extreme miniaturization, with reproductive organs occupying just 1.45% of body volume yet retaining full function within a compact abdomen. Females possess eight tightly interwoven ovarioles that maximize coelomic space for oocyte maturation, maintaining a slender form while housing large eggs-reflecting an evolutionary trade-off between reproductive efficiency and body size. Our reconstructions resolve a key ambiguity: the female accessory glands are a pair of fused, S-shaped structures joined by an internal duct opening near the ovipositor base. Quantitative analysis reveals the first complete germ cell census, with asymmetric ovary cell numbers suggesting an adaptive strategy for sustained fecundity. By integrating detailed morphology with systematic quantification, this study creates a foundation for research in functional morphology and for developing reproduction-targeted pest management. The structural insights enable precise strategies to disrupt thrips reproduction and reduce virus spread. Beyond advancing pest control innovation, the findings serve as a valuable educational and reference resource in insect morphology.
Volume electron microscopy (vEM) enables nanoscale visualization of three-dimensional (3D) cellular ultrastructure, providing critical insights into physiological processes and pathological alterations. However, its application to large-scale biological tissues remains constrained by two major bottlenecks: prolonged image acquisition and inefficient data processing. Here, we present EMCF ecosystem (EMCFsys), an integrated ecosystem designed to overcome these challenges through three key components: a large-scale benchmark dataset (EMCFD) comprising 4,002,802 high-quality images across 14 EM modalities and 6 biological kingdoms; a foundation image restoration model (EMCellFiner); and a scalable image analysis foundation model (EMCellFound). Together, these modules systematically enhance image quality and substantially improve analysis efficiency. Our results show that EMCellFiner outperforms specialist models in restoring degraded images, even surpassing original ground truth sharpness in certain artifact regions, and reduces imaging time by 16-fold by enabling low-resolution and low dwell time acquisition. EMCellFound exhibits exceptional feature discriminability, outperforms specialist models in classification, semantic segmentation and instance segmentation. It also enables high-precision 3D reconstruction of organelles (e.g., endoplasmic reticulum) with minimal labeled data (0.01% of total volume). We validated the EMCFsys on unseen datasets across diverse biological contexts and imaging platforms. By publicly releasing both the dataset and models, we establish a scalable paradigm for automated, high-throughput vEM data interpretation, accelerating exploration of life’s nanoscale structure and function across biology.
The brown planthopper (Nilaparvata lugens) has a high reproductive rate, posing a significant challenge to biological control of rice pests. This is largely due to the physiological and functional traits of its telotrophic ovarioles, which feature a centralized nutrient supply to ensure each oocyte obtains essential basic nutrients. Current studies on insect ovarioles primarily focus on hormonal regulation and gene expression; the cellular composition and spatial relationships within N. lugens ovariole tissues remain poorly understood. To illustrate the internal architecture of ovarioles and the intricate oogenesis process at nanoscale resolution, this study employed focused ion beam-scanning electron microscopy for 3D volume reconstruction, overcoming limitations of traditional 2D electron microscopy. Using this advanced imaging technique, we systematically characterized key ovariole components including terminal filaments, trophocytes, germ cell clusters, three types of follicular cells, nutritive cords, and oocytes. Our findings reveal that rather than maintaining a continuous linkage, the nutritive cord transiently connects to the oocytes during specific developmental stages to facilitate nutrient transfer. An assembly of unique, cake-like phospholipoglycoproteins was identified within the oocytes, suggesting specialized energy storage mechanisms. The detailed 3D model elucidates the spatial relationship and relative position between various parts of the ovariole, offering novel insights into the mechanisms of oocyte growth and nutrient acquisition. These findings advance foundational knowledge of insect reproductive biology and provide a valuable framework for future research on pest control strategies targeting N. lugens reproduction.
The fine structure of the globally distributed phytophagous mite, Tetranychus urticae, has been elucidated using serial block-face scanning electron microscopy (SBF-SEM) combined with 3D reconstruction. The reconstructed models reveal previously unknown internal adaptations tailored to its unique lifestyle. These include a specialized food ingestion structure to facilitate effective cell-sucking, a semi-closed-loop tracheal system optimized for efficient oxygen diffusion in a minute organism, and a pair of well-developed silk glands utilized for water repellency, defense and dispersion. Notably, the midgut occupies nearly the entire body cavity, housing 189 (male) and 636 (female) suspended digestive cells, except for the reproductive system. No observable connections or channels were found linking two midgut regions (ventriculus and posterior midgut), nor were valve structures or controlling muscles detected in this region in most cases, suggesting the presence of an intermittent, dynamically regulated midgut. This adaptation may address the functional demands of unique digestive cells suspended within the ventriculus. However, a funnel-shaped midgut capable of forming temporary channels for the disabled transport of digestive cells from the ventriculus to the posterior midgut was identified. These findings profoundly advance our understanding of how minute animals adapt their internal systems to specialized lifestyles.
Phloem-feeding insects present significant economic threats worldwide and remain challenging to understand due to their specialized feeding strategies. Significant advances in genetics, genomics, and biochemistry have greatly enriched our comprehension of phloem-insect interactions. However, existing studies relying on two-dimensional discrete images have limited our understanding of visible morphological details. In this study, we leverage volume electron microscopy (vEM) technology to unveil a nanometer-resolution interaction mode between plant and the phloem-feeding insect, Camphor psyllid (Trioza camphorae, Hemiptera: Psyllidae). The stylets penetrate each cell on the way to the feeding site (sieve tube), and new cell walls will form around the salivary sheath, ultimately fusing with the original cell walls to form remarkably thickening cell walls. Our reconstruction findings on pit gall tissues suggest that a significant decrease in cell volume and a drastic increase in cell layers are the primary processes during pit gall formation. These unique findings will set the stage for a robust discussion on the plant cellular response induced by phloem-feeding insects.
The enthesis, a fibrocartilaginous tissue connecting tendon or ligament to bone, is critical for joint movement but lacks regenerative capacity after injury. Current clinical treatments for enthesis healing remain limited. Here, with a resolution of 2 to 3 nanometers, we found that mineral particles form a continuous cross-fibrillar phase with a discontinuous distribution in the fibrocartilage layer. Building on this finding, we developed a series of bioinspired mineralized collagen matrices, characterized by both intra- and extrafibrillar localization of crystallites, with a tunable mass percentage of inorganic content as scaffolds for enthesis repair. Our results revealed that mineralized collagen with controlled inorganic content (33% mineral content) facilitated fibrocartilage healing across multiple animal enthesis injury models, including mice, rats, rabbits, and goats. In direct comparisons with other biomaterials in a rabbit model, the bioinspired mineralized collagen resulted in 82% fibrocartilage width recovery, more than two times the healing observed with other materials. Treatment with the bioinspired mineralized collagen scaffold produced joint healing with an ability to sustain a higher maximum load in both rat and rabbit models, with the animals able to walk normally. The goat model exhibited an improvement in jumping ability. Mechanistically, we found that the bioinspired mineralized collagen modulated Hedgehog signaling intensity in a mineralization-dependent manner, which in turn up-regulated Gli1 expression. This modulation regulated the differentiation of mesenchymal progenitor cells and promoted fibrocartilage healing. Overall, we demonstrate that a bioinspired mineralized collagen scaffold effectively promotes enthesis injury repair, demonstrating potential for clinical translation.
Mammalian epididymal epithelial cells are crucial for sperm maturation. Historically, vacuole-like ultrastructures in epididymal epithelial cells were observed via transmission electron microscopy but were undefined. Here, we utilize volume electron microscopy (vEM) to generate 3D reconstructions of epididymal epithelial cells and identify these vacuoles as intercellular organelle reservoirs (IORs) in the lateral intercellular space (LIS), which contains protein aggregates, autophagosomes, lysosome-related organelles and mitochondrial residues. Immunolabelling of organelle markers such as P62, LC3, LAMP1 and TOMM20 confirm these findings. The IOR size or number varies across four epididymal regions and decreases with age. Rab27a mutant mice exhibit reduced IORs in the caput epididymis and a subfertility phenotype, suggesting the involvement of Rab27a in the formation of IORs. Furthermore, we observe the presence of IORs between intestinal epithelial cells besides epididymis. Amino acid transporters at IOR edges suggest dynamic protein recycling. Our findings reveal that the IOR is an important structure critical for organelle turnover and recycling outside epithelial cells with limited self-degradation capabilities.
Plants establish symbiotic associations with root-colonizing microbes to adapt to adverse conditions. However, how root-associated microbiota interacted with their hosts to improve plant growth under nutrient deficient conditions remains poorly understood. In this study, we explored an interaction between tomato plants and root-associated microbiota under iron (Fe) limitation, mediated by bacterial secretion of glutamine. 16S rRNA gene sequencing revealed that Fe-limited conditions altered the composition of root-associated microbiomes, resulting in the enrichment of Ammoniphilus sp. This taxon was isolated and shown to alleviate Fe deficiency symptoms. Moreover, Fe deficiency triggered salicylic acid (SA)-induced hydrogen peroxide (H2O2) burst, thereby inhibiting the exudation of Fe-mobilizing phenolics from the roots. However, bacterial secretion of Gln greatly attenuated the SA-induced H2O2 production in the roots, thereby enhancing bacterial colonization and promoting apoplastic Fe remobilization. Collectively, these results underscored a microbial strategy for orchestrating plant SA pathways to facilitate the reutilization of root apoplastic Fe.
Citrus yellow vein clearing virus (CYVCV) is a worldwide and highly destructive disease of citrus, but the mechanisms involved in CYVCV-inhibited plant growth are not well understood. This study examined nutrient levels and their cellular distribution in different organs of healthy and CYVCV-affected citrus (Citrus reticulata 'Kanpei') plants. We found that CYVCV-infected plants exhibit characteristic symptoms, including a significant reduction in iron (Fe) and other elemental nutrients in the shoots. Our data suggest that CYVCV-induced chlorosis in citrus leaf veins is primarily due to iron deficiency, leading to reduced chlorophyll synthesis. Further analysis revealed a marked decrease in iron concentration within the pith and xylem of citrus petioles post-CYVCV infection, contrasting with increased Fe and zinc (Zn) concentrations in the phloem. Moreover, a substantial accumulation of starch granules was observed in the pith, xylem, and phloem vessels of infected plants, with vessel blockage due to starch accumulation reaching up to 81%, thus significantly obstructing Fe transport in the xylem. Additionally, our study detected an upregulation of genes associated with nicotinamide metabolism and Fe and Zn transport following CYVCV infection, leading to increased levels of nicotinamide metabolites. This suggests that CYVCV-infected citrus plants may induce nicotinamide synthesis in response to Fe deficiency stress, facilitating the transport of Fe and Zn in the phloem as nicotinamide-bound complexes. Overall, our findings provide insight into the mechanisms of long-distance Fe and Zn transport in citrus plants in response to CYVCV infection and highlight the role of nutritional management in mitigating the adverse effects of CYVCV, offering potential strategies for cultivating CYVCV-resistant citrus varieties. Citrus yellow vein clearing virus induces citrus vein yellowing by limiting xylem iron transport and enhancing nicotinamide-bound complexes in phloem, offering insights for nutrition-based mitigation.
The olfactory system is involved in food and mate recognition in insects. However, 3D structures of chemosensory sensilla in insects are unexplored yet. Here, the internal structures of an olfactory sensillum on the antenna of the brown planthopper, Nilaparvata lugens (Hemiptera: Delphacidae), one of the most important rice pests, are examined and imaged using focused ion beam scanning electron microscopy. Based on these images, a 3D structure is reconstructed in this study. We find that the trichoid olfactory sensillum possesses a multiporous wall encircling a lumen with one sensory cell. Besides, there are three accessory cells (ACs) and a glia cell with different cell contents surrounding the sensory cell. The abundant tubular membrane structures in the tormogen cell suggest its role in secreting proteins like odorant binding proteins into the receptor lymph, while three auxiliary cells with simpler cellular content closely enfold the sensory cell, probably to prevent leaking of the receptor lymph into the surrounding epidermis. In the sensory cell, the microtubules and two tandem basal bodies at the base of the microtubules are also reconstructed. They are considered as a propulsive engine to ensure dendrite vibration or spinning in the receptor lymph, so that the proteins and odorant molecules move faster in the receptor lymph, which improves recognition of environmental odors and enables the insect to immediately respond to this information.
Intercropping is emerging as a sustainable strategy to manage soil-borne diseases, yet the underlying mechanisms remain largely elusive. Here, we investigated how intercropping chrysanthemum (Chrysanthemum morifolium) with ginger (Zingiber officinale) suppressed Fusarium wilt and influenced the associated rhizo-microbiome. Chrysanthemum plants in intercropping systems exhibited a marked reduction in wilt severity and greater biomass compared to those grown in monoculture. In contrast, soil sterilization intensified wilt severity and abrogated the benefits of intercropping, highlighting the critical role of soil microbiota. 16S rRNA gene amplicon analysis revealed that intercropping significantly changed the composition and structure of rhizo-bacterial communities, particularly enriching Burkholderia species, which were closely associated with plant growth and disease resistance. Further investigation demonstrated that ginger root exudates, including sinapyl alcohol and 6-gingerol, greatly promoted the proliferation and colonization of Burkholderia sp. in chrysanthemum rhizosphere, conferring the enhanced disease suppression. Metabolomic profiling revealed that ginger root exudates stimulated the release of specific metabolites by chrysanthemum roots, which promoted the growth and biofilm formation of Burkholderia sp. Our findings uncovered the mechanism by which intercropping chrysanthemum with ginger plants modulated the rhizo-microbiome and thereby resulted in the enhanced disease suppression, offering insights into optimizing plant-microbe interactions for improving crop health and productivity.
Widely present in mammalian proteomes, intrinsically disordered regions (IDRs) in proteins play important biological functions by conferring structural flexibility and mediating biomolecular interactions. IDR-containing proteins, including many RNA-binding proteins (RBPs), are prone to misfolding and aggregation and must be constantly monitored. Here we show that the conserved ZSWIM8-type Cullin-RING ubiquitin ligase (CRLZSWIM8) is a master regulator of such proteins during brain development. ZSWIM8 selects its substrates via an IDR-dependent mechanism, and deletion of ZSWIM8 causes aberrant accumulation of numerous RBPs including AGO2 and ELAV1 in neonatal brains. Furthermore, AGO2 ubiquitination by ZSWIM8 is triggered by microRNA binding, leading to target-directed microRNA degradation (TDMD) of MiR7. Dysregulation of MiR7 in the absence of ZSWIM8 results in defects in oligodendrocyte maturation and functions. Together, our findings have demonstrated that, by utilizing variable target-recognition strategies, ZSWIM8 controls the abundance of conformationally flexible RBPs and miRNA metabolism that are essential for brain development.Teaser A conserved ubiquitin ligase controls the quality of disordered proteins to ensure brain development.### Competing Interest StatementThe authors have declared no competing interest.
Lysosomal Storage Disorders (LSDs), which share common phenotypes, including enlarged lysosomes and defective lysosomal storage, are caused by mutations in lysosome-related genes. Although gene therapies and enzyme replacement therapies have been explored, there are currently no effective routine therapies against LSDs. During lysosome reformation, which occurs when the functional lysosome pool is reduced, lysosomal lipids and proteins are recycled to restore lysosome functions. Here we report that the sorting nexin protein SNX8 promotes lysosome tubulation, a process that is required for lysosome reformation, and that loss of SNX8 leads to phenotypes characteristic of LSDs in human cells. SNX8 overexpression rescued features of LSDs in cells, and AAV-based delivery of SNX8 to the brain rescued LSD phenotypes in mice. Importantly, by screening a natural compound library, we identified three small molecules that enhanced SNX8–lysosome binding and reversed LSD phenotypes in human cells and in mice. Altogether, our results provide a potential solution for the treatment of LSDs.
The silk-spinning process of the silkworms transforms the liquid silk solution to a solid state under mild conditions, making it an attractive model for bioinspiration However, the precise mechanism behind silk expulsion remains largely unknown. Here we selected the silkworms as representative models to investigate the silk-spinning mechanism. We used serial block-face scanning electron microscopy (SBF-SEM) to reconstruct the three-dimensional structures of the spinnerets in silkworms at various stages and with different gene backgrounds. By comparing the musculature and duct deformation of these spinneret models during the spinning process, we were able to simulate the morphological changes of the spinneret. Based on the results, we proposed three essential factors for silkworm spinning: the pressure generated by the silk gland, the opening duct, and the pulling force generated by head movement. Understanding the silkworm spinning process provides insights into clarify the fluid-ejecting mechanism of a group of animals. Moreover, these findings are helpful to the development of biomimetic spinning device that mimics the push-and-pull dual-force system in silkworms.
The oocyte cumulus complex is mainly composed of an oocyte, the perivitelline space, zona pellucida and numerous granulosa cells. The cumulus granulosa cells (cGCs) provide a particularly important microenvironment for oocyte development, regulating its growth, maturation and meiosis. In this study, we studied the internal structures and cell-to-cell connections of mouse cGCs using focused ion beam scanning electron microscopy (FIB-SEM). We reconstructed three-dimensional models to display characteristic connections between the oocyte and cGCs, and to illustrate various main organelles in cGCs together with their interaction relationship. A special form of cilium identified in granulosa cell was never reported in previous literature.