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Organellar ion channels are regulators of key processes of cellular homeostasis as well as being involved in diseases including cancer, neurological disorders and virus infection. Individual organelle-level electrophysiology has until recently only been performed using isolated organelles, removing any direct physiological context. New DNA-based nanodevices — Clensor (chloride sensor), RatiNa (sodium sensor) and pHlicKer (potassium sensor), now allow imaging-based mapping of sodium and potassium levels in membranous organelles. This breakthrough paves the way for studying ion homeostasis relevant to a variety of diseases as well as fundamental processes.

Gangliosides in the outer leaflet of the plasma membrane of eukaryotic cells are essential for many cellular functions and pathogenic interactions. How gangliosides are dynamically organized and how they respond to ligand binding is poorly understood. Using fluorescence anisotropy imaging of synthetic, fluorescently labeled GM1 gangliosides incorporated into the plasma membrane of living cells, we found that GM1 with a fully saturated C16:0 acyl chain, but not with unsaturated C16:1 acyl chain, is actively clustered into nanodomains, which depends on membrane cholesterol, phosphatidylserine and actin. The binding of cholera toxin B-subunit (CTxB) leads to enlarged membrane domains for both C16:0 and C16:1, owing to binding of multiple GM1 under a toxin, and clustering of CTxB. The structure of the ceramide acyl chain still affects these domains, as co-clustering with the glycosylphosphatidylinositol (GPI)-anchored protein CD59 occurs only when GM1 contains the fully saturated C16:0 acyl chain, and not C16:1. Thus, different ceramide species of GM1 gangliosides dictate their assembly into nanodomains and affect nanodomain structure and function, which likely underlies many endogenous cellular processes. Gangliosides such as GM1 present in the outer leaflet of the plasma membrane of eukaryotic cells are essential for many cellular functions and pathogenic interactions. Here the authors show that the acyl chain structure of GM1 determines the establishment of nanodomains when actively clustered by actin, which depended on membrane cholesterol and phosphatidylserine or superimposed by the GM1-binding bacterial cholera toxin.

Functionalization of quantum dots (QDs) with a single biomolecular tag using traditional approaches in bulk solution has met with limited success. DNA polyhedra consist of an internal void bounded by a well-defined three-dimensional structured surface. The void can house cargo and the surface can be functionalized with stoichiometric and spatial precision. Here, we show that monofunctionalized QDs can be realized by encapsulating QDs inside DNA icosahedra and functionalizing the DNA shell with an endocytic ligand. We deployed the DNA-encapsulated QDs for real-time imaging of three different endocytic ligands—folic acid, galectin-3 (Gal3) and the Shiga toxin B-subunit (STxB). Single-particle tracking of Gal3- or STxB-functionalized QD-loaded DNA icosahedra allows us to monitor compartmental dynamics along endocytic pathways. These DNA-encapsulated QDs, which bear a unique stoichiometry of endocytic ligands, represent a new class of molecular probes for quantitative imaging of endocytic receptor dynamics. Quantum dots encapsulated inside DNA icosahedra that display a single endocytic ligand are used to track compartmental dynamics along endocytic pathways.

Endophilin-A2 (endoA2) is shown to mediate clathrin-independent endocytosis of Shiga and cholera toxins, and to function in parallel with dynamin and actin in the pulling-force-driven scission of Shiga-toxin-induced tubular structures. Endocytosis and cell signalling Cells internalize nutrients and turnover membrane components through the process of endocytosis, which in most cases involves the protein clathrin. Endophilin has been thought to be a component of clathrin-mediated endocytosis, but two studies published in this issue of Nature show that this protein mediates a fast-acting, clathrin-independent form of endocytosis which involves formation of tubular vesicles. Emmanuel Boucrot et al . report that this pathway is triggered by binding of ligands to cargo receptors, and requires the proteins dynamin and actin. Endophilin-mediated endocytosis also seems to have distinct cellular homes, occurring at the leading edges of cells where the lipid PtdIns(3,4)P 2 ensures endophilin engagement. This form of endocytosis is shown to mediate the uptake of several physiological and disease-relevant receptors including G-protein-coupled receptors and receptor tyrosine kinases. In the second paper, Henri-François Renard et al . provide evidence that bacterial toxins take advantage of the same pathway to enter cells, and also find that endophilin-A2 acts together with dynamin and actin. During endocytosis, energy is invested to narrow the necks of cargo-containing plasma membrane invaginations to radii at which the opposing segments spontaneously coalesce, thereby leading to the detachment by scission of endocytic uptake carriers 1 . In the clathrin pathway, dynamin uses mechanical energy from GTP hydrolysis to this effect 2 , 3 , 4 , assisted by the BIN/amphiphysin/Rvs (BAR) domain-containing protein endophilin 5 , 6 . Clathrin-independent endocytic events are often less reliant on dynamin 7 , and whether in these cases BAR domain proteins such as endophilin contribute to scission has remained unexplored. Here we show, in human and other mammalian cell lines, that endophilin-A2 (endoA2) specifically and functionally associates with very early uptake structures that are induced by the bacterial Shiga and cholera toxins, which are both clathrin-independent endocytic cargoes 8 . In controlled in vitro systems, endoA2 reshapes membranes before scission. Furthermore, we demonstrate that endoA2, dynamin and actin contribute in parallel to the scission of Shiga-toxin-induced tubules. Our results establish a novel function of endoA2 in clathrin-independent endocytosis. They document that distinct scission factors operate in an additive manner, and predict that specificity within a given uptake process arises from defined combinations of universal modules. Our findings highlight a previously unnoticed link between membrane scaffolding by endoA2 and pulling-force-driven dynamic scission.

Navigation assistance is becoming increasingly important for visually impaired and the elderly, as traditional tools often lack sufficient feedback for safe, independent mobility. With recent advancements in assistive technology, particularly in smart canes, the internet of things (IoT) is integrated with artificial intelligence (AI) to enable real-time environmental awareness. This paper traces the evolution of simple white canes into advanced devices fitted with sensors and computer vision technology, guiding users through real-time audio and sensory feedback. Additionally, a comparative analysis of object detection models-Faster Regional Convolutional Neural Network (Faster R-CNN), You Only Look Once (YOLO), and Single Shot MultiBox Detector (SSD)-used in assistive devices is presented to aid visually impaired and elderly users in detecting hazards. The accuracy, processing time, and real-time feasibility of each model were evaluated. Simulation results indicated that YOLO-v8 outperformed Faster-RCNN and SSD, achieving the highest accuracy of 92.6% under the same testing conditions. In summary, the integration of IoT and AI has significantly enhanced the functionality of navigation assistance devices, improving safety, independence, and quality of life for the elderly and people with vision impairment.

As agriculture plays a vital role responsible for sustaining the growing population, it is important to enhance crop health monitoring to ensure food security and maximize farming methods. This paper presents an extensive review of crop health monitoring systems, with the integration of artificial intelligence ( AI ), computer vision, and the Internet of Things ( IoT ). The efficacy of several approaches, such as sensor-based networks, data-driven prediction models, and image processing techniques, in predicting plant diseases and improving agricultural yield is explored. Key deep learning architecture models for image classification, such as -- Convolutional Neural Networks (CNNs), Data Augmentation, Transfer Learning, and You Only Look Once (YOLO) , for plant disease identification are discussed. Using an image classification process via CNN, the images of a few leaves and other plant traits are analyzed to distinguish between healthy and unhealthy crops. Further, key parameters such as temperature, humidity, soil moisture, and pH levels are continuously monitored through sensor networks integrated into agricultural systems, in order to get the details of crop health. For optimal crop growth, the soil needs to be nutrient-rich with a pH level between 6.5 and 7.5 to increase the soil’s fertility. In conclusion, crop health monitoring using AI and computer vision has proven highly effective, with a 92% accuracy in plant disease detection. Through this integration, farmers are empowered to take preventive measures, reduce losses, and maximize their crop yields. This study paves the way for future advancements in sustainable farming by utilizing innovative technologies.

In Escherichia coli , a contractile ring (Z-ring) is formed at midcell before cytokinesis. This ring consists primarily of FtsZ, a tubulin-like GTPase, that assembles into protofilaments similar to those in microtubules but different in their suprastructures. The Min proteins MinC, MinD, and MinE are determinants of Z-ring positioning in E. coli . MinD and MinE oscillate from pole to pole, and genetic and biochemical evidence concludes that MinC positions the Z-ring by coupling its assembly to the oscillations by direct inhibitory interaction. The mechanism of inhibition of FtsZ polymerization and, thus, positioning by MinC, however, is not understood completely. Our in vitro reconstitution experiments suggest that the Z-ring consists of dynamic protofilament bundles in which monomers constantly are exchanged throughout, stochastically creating protofilament ends along the length of the filament. From the coreconstitution of FtsZ with MinCDE, we propose that MinC acts on the filaments in two ways: by increasing the detachment rate of FtsZ-GDP within the filaments and by reducing the attachment rate of FtsZ monomers to filaments by occupying binding sites on the FtsZ filament lattice. Furthermore, our data show that the MinCDE system indeed is sufficient to cause spatial regulation of FtsZ, required for Z-ring positioning.

Endosomal maturation is critical for robust and timely cargo transport to specific cellular compartments. The most prominent model of early endosomal maturation involves a phosphoinositide-driven gain or loss of specific proteins on individual endosomes, emphasising an autonomous and stochastic description. However, limitations in fast, volumetric imaging long hindered direct whole cell-level measurements of absolute numbers of maturation events. Here, we use lattice light-sheet imaging and bespoke automated analysis to track individual very early (APPL1-positive) and early (EEA1-positive) endosomes over the entire population, demonstrating that direct inter-endosomal contact drives maturation between these populations. Using fluorescence lifetime, we show that this endosomal interaction is underpinned by asymmetric binding of EEA1 to very early and early endosomes through its N- and C-termini, respectively. In combination with agent-based simulation which supports a ‘trigger-and-convert’ model, our findings indicate that APPL1- to EEA1-positive maturation is driven not by autonomous events but by heterotypic EEA1-mediated interactions, providing a mechanism for temporal and population-level control of maturation. Newly formed endosomes mature into early endosomes by shedding one protein and acquiring another. Here, the authors describe a trigger-and-convert mechanism driven by endosomal collisions and fusions that govern timeliness in ensemble maturations.

Nanofiltration is an important application for electro-spun fiber as it is well characterized by fine fiber diameter, huge density, high penetrability, and flexibility. In this paper, the poly-acrylonitrile fiber diameter is determined experimentally by varying four factors such as voltage, flow rate, the distance between spinneret and collector, and mass fraction in the electrospinning process. The fiber diameter is measured through SEM analysis. A highly accurate kernel-based non-linear multivariable grey model, KGM (1, 1) model is used for the prediction of nanofiber diameter for filtering particulate less than 500 nm. This is proved to be better when compared to the grey model first order one variable and multivariable grey model. Based on simulated outcomes, filtration membranes are prepared and tested for filtration efficiency for the airborne particles relating its air permeability, porosity and quality factor.

RNA viruses encode multifunctional proteins to overcome limited genomic capacity and mediate diverse processes in viral replication and host cell modulation. The rabies virus P gene encodes full-length P1 protein and the truncated isoform, P3, which acquires phenotypes absent from P1, including interactions with cellular membrane-less organelles (MLOs) formed by liquid-liquid phase separation (LLPS). This gain-of-function suggests that isoform multifunctionality arises not only from discrete functions of protein modules/domains, but also from conformational regulation involving interactions of the globular C-terminal domain and N-terminal intrinsically disordered regions (IDRs). The precise mechanisms underlying gain-of-function, however, remain unresolved. Here, we compare the structure and function of P1 and P3, identifying isoform-specific long-range intra-protomer interactions between the IDRs and C-terminal domain that correlate with conformational states, LLPS behavior, and subcellular localization. Mutations in P3 that alter MLO interactions correspondingly modulate these interactions. P1 and P3 can interact with similar/overlapping sets of MLO-associated proteins and have similar LLPS capacity, but only P3 binds RNA, and this interaction correlates with gain-/loss-of-function mutations. Our findings reveal that conformational differences in isoforms regulate LLPS behavior and contribute to protein-RNA interactions, which controls access to host LLPS structures, uncovering a previously unrecognized strategy in P protein multifunctionality. Viral proteins can achieve high multifunctionality, but mechanisms are poorly understood. This study shows structural flexibility of rabies virus P protein enables RNA binding and phase separation to expand functions by infiltrating host condensates.