Marine sponges and ammonia-oxidizing archaea (AOA) represent one of the earliest animal-microbe symbioses. AOA are considered metabolically constrained chemolithoautotrophs that remove nitrogenous waste within the sponge holobiont. Here, we expand this view by demonstrating that symbiotic AOA assimilate branched-chain amino acids (BCAA) as additional carbon and nitrogen sources. By combining stable isotope probing with fluorescence and chemical imaging, we trace the assimilation of 13 C- and 15 N-labeled BCAA (leucine, isoleucine, and valine) in the sponge holobiont Ianthella basta at single-cell resolution. We show that the ability to take up, degrade, and biosynthesize BCAA is a common adaptation among symbiotic AOA lineages. This ability may enable symbiotic AOA to modulate BCAA concentrations in their auxotrophic sponge hosts. Modulation of BCAA availability by symbionts may regulate the leucine-sensitive mTOR (mechanistic target of rapamycin) signaling pathway in sponges.
Pt-Ni alloys exhibit outstanding oxygen reduction reaction (ORR) activity, yet achieving structural ordering to enhance stability remains a persistent challenge. Here, we propose a database-guided screening strategy to identify promoter elements (X) that facilitate ordering. By screening the critical disorder-to-order transition temperature ([Formula: see text]), solid solubility ([Formula: see text]), and diffusion pre-exponential factor ([Formula: see text]) of candidate elements from material databases, six sets of L10-Pt(NiX) nanoparticles were synthesized. The developed L10-PtNiFe catalysts demonstrated a high mass activity (MA) of 4.38 A mgPt-1, retaining 82.1% after 50,000 cycles of accelerated durability testing (ADT) in half-cells, and retaining 79% of its initial MA of 1.1 A mgPt-1 after 30,000 cycles in membrane electrode assembly (MEA). Theoretical calculations reveal that X incorporation broadens the annealing temperature ([Formula: see text]) window by forming Pt(NiX) with higher [Formula: see text] and lowering the kinetic threshold temperature ([Formula: see text]) via enhanced atom mobility. This work establishes a database-guided framework that enables phase transitions previously difficult to access by creating an effective annealing window through coordinated thermodynamic-kinetic regulation, thereby facilitating the formation of ordered PtNi-based intermetallic structures toward durable electrocatalysts.
Pt-based intermetallic compounds with atomically ordered arrangements are highly promising catalysts for the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells. However, the mutual constraint between high-temperature ordering and small-size stability (especially at high metal loadings), as well as the corrosion of both metal particles and carbon supports under operating conditions, severely limit their mass activity and long-term durability. Here, we report a borophene-mediated multimetal site co-anchoring strategy to synthesize sub-4-nanometer high-entropy Pt4FeCoNiCu intermetallic catalysts (MMCA-HEIMCs) supported on pristine carbon, which enables simultaneous anchoring of Pt and non-noble metals onto the carbon support. The strong metal-borophene interaction suppresses particle sintering during high temperature annealing (1000°C) and enables a high metal loading of 36 wt % at a small particle size. The resulting L10-ordered structure with a unique FeCoNiCu atomic stacking configuration is confirmed by electron microscopy and x-ray absorption spectroscopy. The catalyst achieves an exceptional H2-air fuel cell peak power density of 1.055 watts per square centimeter and an ORR mass activity of 1.4 amperes per milligram of Pt at 0.9 volts in H2-O2 fuel cells. Owing to the high-entropy stabilization effect and the robust borophene co-anchoring effect, the catalyst retains 72% of its peak power density and 80% of its initial mass activity after 30,000 durability cycles. Moreover, the borophene interlayer mitigates Pt-catalyzed carbon corrosion, as verified by a 5000 startup/shutdown cycling test and online mass spectrometry. This work demonstrates a general strategy to overcome the activity-durability trade-off in multicomponent intermetallic catalysts through strong metal-support interactions.
Quantum interference in cold collisions has been predicted to dominate chemical dynamics at low temperatures. However, experimental observations have been largely confined to light-atom systems due to technical challenges. Here, we report direct observation of scattering oscillations in cold ionizing collisions between metastable krypton and rubidium atoms. By combining laser cooling with velocity-mapped ion imaging, we precisely controlled the collision energy from 15 millikelvin to 8 kelvin and detected the ionization products. Below 1 kelvin, pronounced quantum interference between partial waves emerges as the de Broglie wavelength approaches the interaction range. The angular oscillation period scales as [Formula: see text], consistent with a Langevin capture model for van der Waals-dominated collisions. Moreover, interference patterns in the angular distribution-collision temperature spectrum are highly sensitive to the long-range potential shape and reveal subtle shape resonances. These observations were corroborated by theoretical calculations. Our results demonstrate the quantum-classical crossover in heavy-atom systems. This study establishes a versatile platform for studying a wide range of laser-coolable species.
Chlorophylls are essential for photosynthesis, yet their heterologous production is a major challenge in synthetic biology due to pathway complexity and the diversion of resources away from essential cofactor biosynthesis. Here, we reconstruct the complete chlorophyll biosynthetic pathway in Saccharomyces cerevisiae. By integrating 13 heterologous genes and deleting 3 endogenous genes, we engineered a yeast chassis capable of producing chlorophyll a at titers of 26 micrograms per gram of dry cell weight. This platform was further expanded with a ketocarotenoid biosynthetic module to produce echinenone and canthaxanthin, enabling the in vivo coassembly of two distinct pigment-protein complexes: the plant-derived water-soluble chlorophyll protein and the cyanobacterial orange carotenoid protein (Syn_OCP). Spectroscopic and biochemical analyses confirm that these yeast-assembled complexes retain native spectral and functional signatures, including Syn_OCP photoactivity, demonstrating high-fidelity pigment binding. Our work establishes a versatile eukaryotic platform for producing photosynthetic complexes, which could help open avenues for studying their assembly outside plants and for engineering light-driven metabolism in nonphotosynthetic eukaryotes.
Key innovations open ecological opportunities and can redirect evolutionary trajectories. In spiny-finned fishes, the pelvic suction cup—a fused adhesive structure formed from the pelvic fins and supported by a modified girdle—appears to be one such trait. Using a novel 960-species phylogeny spanning 940 exons and 67 newly sequenced snailfish genomes, we show that the suction cup evolved independently three times across lineages separated by over 100 million years. By enabling adhesion in high-energy habitats such as tide pools and waterfalls, the suction cup set the stage for body depression and accompanying shifts in scales, teeth, and clade-specific ecofunctional profiles. Comparative analyses reveal convergence in a distinctive region of morphospace and body-shape evolution accelerated two- to fivefold. Diversification analyses uncover heterogeneous but elevated rates, with a clear burst in rock-climbing gobies associated with suction cup evolution. By opening novel habitats and fostering phenotypic novelty, the suction cup emerges as a key innovation that reshaped spiny-finned fish evolution.
The therapeutic potential of interleukin-2 (IL-2) in cancer treatment is limited by toxicity challenges, partly due to an unfavorable pharmacokinetic profile and unintended activation of regulatory T (Treg) cells alongside the desired activation of CD8+ effector T cells. To selectively stimulate CD8+ T cells over Treg cells, we engineered an IL-2 variant (IL-2var) with a dual-tuned affinity profile that features reduced binding to IL-2Rα (CD25) and enhanced binding to IL-2Rβ (CD122). To optimize its pharmacokinetics and facilitate tumor enrichment, the variant is fused to albumin and delivered as an mRNA encapsulated in a lipid nanoparticle (Alb-IL-2var RNA-LNP), enabling sustained systemic exposure from hepatic production upon intravenous administration. We show that Alb-IL-2var has a favorable pharmacokinetic profile and is tolerated at biologically active doses in immunocompetent mice and cynomolgus monkeys. Selective enhancement of CD8+ T cell responses over Treg cells is demonstrated in vitro in human peripheral blood mononuclear cells and in vivo in mice and cynomolgus monkeys. When combined with an mRNA cancer vaccine in syngeneic subcutaneous mouse tumor models, Alb-IL-2var RNA-LNP stimulates the expansion of tumor-infiltrating and circulating tumor antigen-specific CD8+ T cells, but not Treg cells. In advanced and cold syngeneic tumor models, it enhances the efficacy of radiotherapy, checkpoint inhibitors, and cancer vaccines. Combination with checkpoint inhibitors and vaccine induces profound proinflammatory conversion of cold tumors. These preclinical results validate a rational design approach to overcome the limitations of IL-2 therapy and support the clinical evaluation of Alb-IL-2var RNA-LNP for solid cancers.
Sweat secretion provides insights into physiological and psychological states. However, the current single detection method is not compatible with the simultaneous monitoring of gaseous and liquid sweat, which restricts its application for exploring dynamic physiological processes. Herein, a fully integrated sweat sensor with a heterophase shunt for full-range sweat rate monitoring is reported. Through non-interfering integration of epidermal microfluidic conductivity sensing and humidity detection, continuous measurement across 0.182 ∼ 10 μL/(min·cm2) is achieved. The LiCl-doped UiO-66-NH2 enables a highly sensitive and fast-responding humidity sensor. The biomimetic heterophase shunt, composed of a polydimethylsiloxane and polymethyl methacrylate co-electrospun membrane, exhibits superhydrophobicity (151.9°), gas-permeable [58.07 g/(H·m2)], and water pressure tolerance (1.1 kPa). Heterophase shunt effectively integrates sweat detection modes while providing protection for humidity sensor against sweat corrosion and skin contact-induced damage. Integrated with a specialized weak-signal processing module, the sensor allows applications in psychology, skin health and body dehydration evaluating.
During random foraging, the positional signal decoded from entorhinal grid cells exhibits left-right theta sweeps, alternating from one side of the head direction to the other across successive theta cycles. Here, we report that theta sweeps are topographically organized along the dorsoventral axis of the medial entorhinal cortex, with the angular deviation from head direction increasing gradually from dorsal (smaller scale) to ventral (larger scale) modules. This gradient coexists with a corresponding dorsoventral increase in angular deviation decoded from theta-modulated direction cells, which drive grid cell theta sweeps. These phenomena parallel a broadening of head direction tuning and increasing occurrence of theta cycle skipping in single-cell firing along the dorsoventral axis. Computational modeling demonstrates that these patterns are consistent with continuous attractor dynamics and a dorsoventral gradient in firing rate adaptation. These results highlight how theta sweeps can simultaneously represent multiple potential future locations and reveal a clear neural mechanism underlying this process.
Photochemical oxidation in the aqueous phase is critical for chemical evolution of secondary organic aerosols (SOA), but it represents one of the most uncertain processes in aerosols and clouds. Here, we show that photoirradiation of SOA derived from biomass burning precursors leads to substantial formation of superoxide. The combination of laboratory measurements and kinetic modeling reveals that superoxide generation is driven by photosensitization reactions in aromatic SOA, while the dominant source of superoxide in biogenic SOA is photoinduced decomposition of carbonyls with minor contributions from peroxide decomposition. These processes serve as a substantial source of reactive oxygen species (ROS) including hydrogen peroxide and hydroxyl radical in cloud droplets and deliquesced particles, competing with traditional sources such as uptake from the gas phase. This previously unrecognized source of ROS will enhance the impact of aqueous-phase processing on composition and properties of aerosols and clouds.
Ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) is an important but challenging protein engineering target. Fast and selective rubiscos could enhance photosynthesis in plants and accelerate biobased production processes. To facilitate engineering of rubisco, we applied an in vivo screen that couples rubisco activity to growth rate of the photoautotrophic cyanobacterium Synechocystis sp. PCC 6803. We screened a barcoded mutagenesis library of the form II rubisco from Gallionella sp. containing 15,000 single-site and multi-site variants. Exchanges in loop 6 near the active site, at the dimer interface, and in potential gas tunnels improved rubisco fitness. The dataset also informed protein engineering, using recombination and a trained transformer model. In vitro characterisation of two high-fitness variants showed reduced catalytic efficiency for oxygenation ( k cat /K o ) in both and an increased carboxylation turnover ( k cat C ) in one. This large labeled fitness dataset, containing examples of epistasis, can be useful for benchmarking computational models of rubisco.
Mitohormesis, whereby transient mitochondrial stress induces adaptive signaling, promotes organismal resilience and longevity in invertebrates, but how this operates in mammals and the underlying metabolic signals involved remain unclear. Using a mouse model of mitohormesis, we show that transient mitochondrial superoxide stress during embryogenesis reprograms the adult heart to enhance mitochondrial biogenesis and antioxidant capacity. These adaptations confer protection against mitochondrial and oxidative injury in models of doxorubicin-induced cardiotoxicity, preserving mitochondrial content and preventing cardiac dysfunction and remodeling. Using a cell model of superoxide-mediated mitohormesis, we find that inhibition of mitochondrial aconitase promotes citrate export to the cytosol, where its conversion to acetyl-coenzyme A drives histone acetylation and mitohormetic protection from oxidative stress. Preventing mitochondrial citrate export abolishes these adaptations, while Aco2 silencing or citrate supplementation recapitulates the response. Together, our findings identify mitochondrial citrate as a redox-sensitive second messenger linking mitochondrial superoxide stress to durable epigenetic and mitohormetic remodeling.
Mitochondrial DNA (mtDNA) mutations accumulate with age, but their mechanistic contribution to aging remains unclear. The classical mtDNA mutator mouse expresses a proofreading-deficient mtDNA polymerase (POLG D257A ) and accumulates mtDNA mutations across all tissues leading to premature aging. However, this model cannot resolve whether the aging phenotype results from systemic dysfunction or cell-intrinsic effects of somatic mtDNA mutations. To overcome this limitation, we generated Polg iMut mice allowing spatial and temporal control of POLG D257A expression. We demonstrate here that mtDNA mutations induced in cardiomyocytes cause progressive contractile dysfunction and respiratory chain deficiency in the heart without accompanying systemic pathology. Proteomic analyses link cardiac mosaic respiratory chain dysfunction to a progressive immune response, characterized by up-regulation of antigen-processing proteins and immune cell infiltration. In contrast, longevity-associated pathways are suppressed and uncoupled from mitochondrial and immune alterations, indicating distinct regulatory mechanisms. These findings demonstrate that mtDNA mutations can drive cardiac dysfunction and reveal a mechanistic link between mitochondrial dysfunction, immune responses, and aging.
Group III metabotropic glutamate receptors (mGluRs) are critical signaling molecules that regulate strength, homeostasis, and plasticity of glutamatergic synaptic signaling. These receptors are engaged in transsynaptic interactions with extracellular leucine-rich repeat and fibronectin type III domain-containing (ELFN) cell adhesion proteins. ELFN proteins have been shown to play a critical role in regulation of activity and localization of mGluRs activity in vivo, yet the exact nature of their regulatory interaction has remained unknown. Here, we present a cryo-electron microscopy structure of the ELFN-mGluR complex. We identify a specific ELFN-binding pocket on mGluRs involved in its allosteric regulation through the network of residues affecting the orthosteric ligand binding site. We further uncover cooperativity whereby mGluR activation increases their association with ELFN proteins as a potential feedback mechanism to regulate synaptic strength. Last, we determine that disruption in mGluR-ELFN interaction is a recurring mechanism underlying several neurological conditions as we delineate their structure-functional etiology.
Altered metabolism enables adaptive advantages for cancer cells, driving the need for improved methods for noninvasive long-term monitoring of cellular metabolism. Here, we present a fast live-cell NADH imaging method that provides a real-time measurement of the fractional level of unbound NADH and show that it is a robust indicator of a cell’s metabolic status. The method, two-photon fluorescence polarization ratiometric microscopy (FPRM), is easy and inexpensive to implement and more than an order of magnitude faster than fluorescence lifetime imaging microscopy (FLIM), a common means of assessing bound and unbound NADH levels. We show that FPRM returns instrument-independent ratiometric parameters that correlate with the expected metabolic changes arising from pharmaceutical and environmental perturbations. By correlating FPRM-returned parameters with cell morphology and migration in two- and three-dimensional collagen matrices, we demonstrate the technique’s versatility in typical bioengineered platforms used in cancer metabolism research.
Most voltage-gated potassium (Kv) channels are inhibited by peptide neurotoxins that occlude the pore with a positively-charged lysine. Kv1.5 repels these toxins electrostatically via four arginines (R487), one on each pore-forming subunit. Here, we describe chimera toxin (CmTx), a potent and selective blocker that prefers the slow-inactivated Kv1.5 conformation promoted by rapid firing and acidosis (Ki = 127 nM), conditions associated with atrial fibrillation and ischemia. CmTx was isolated by cell-based, phage-display library panning of de novo peptides engineered on a SAK1 scaffold and shows minimal inhibition of seven other Kv subtypes. Scanning mutagenesis identified CmTx and Kv1.5 residues essential to binding. AlphaFold modeling shows how acidic CmTx residues can neutralize the channel arginines, enabling one peptide to plug the Kv1.5 pore. These findings present an electrostatic pore-blocking mechanism driven by complementary charge interactions and offer CmTx as a tool to probe Kv1.5 physiology and a potential therapeutic lead.
Porphyry copper systems formed in magmatic arcs represent the largest concentrations of copper and most massive anomalies of sulfur worldwide. Whether the ore-fluid-source magmas were dominated by oxidized or reduced sulfur remains the subject of intense debate. Here, we quantitatively measured in situ the relative abundances of S6+, S4+, and S2- in sulfur-bearing primary apatite grains hosted in zircon, amphibole, and biotite in igneous rocks related to porphyry and skarn copper-gold deposits in the Middle-Lower Yangtze River metallogenic belt, Eastern China. Calculated S6+/ΣS ratios of the sulfur-bearing apatite grains vary from 0.18 to 0.97 and are independent of the crystallization pressure and temperature of their host minerals. The data reveal two distinct groups of ore-fluid-source magmas: (i) highly oxidized, dominantly sulfate (anhydrite)-saturated and (ii) relatively reduced, dominantly sulfide-saturated. The results demonstrate that economic porphyry copper systems can form from intermediate-felsic magmas over a broad range of S6+/ΣS ratios and oxygen fugacities (fO2), possibly throughout Earth history including the Proterozoic and Archean.
A formal synthesis of cortistatin A, a marine-derived steroidal alkaloid with potent anti-angiogenic and antileukemic activities, was achieved via a unique synthetic strategy that leveraged a late-stage SmI2-mediated oxa-bridge translocation. The de novo-synthesized simplified analog CA411 was evaluated across 38 cell lines, revealing potent and selective antiproliferative activity against a diffuse large B cell lymphoma (DLBCL) line OCI-Ly3. Time-course transcriptomics and mechanistic studies demonstrated that it disrupts an autocrine IL-6-JAK2-STAT3 signaling loop, reducing IL-6 secretion, STAT3 phosphorylation, and downstream anti-apoptotic genes, thereby inducing apoptosis. Not only this selectivity extends to other CDK8/19 inhibitors and IL-6-dependent models, but CA411 also suppressed OCI-Ly3 xenograft growth, diminished IL-6 expression, induced anti-angiogenic effects with vascular normalization, and prolonged survival in mouse models. These findings position CDK8/19 inhibitors like cortistatins as leads for IL-6-dependent lymphomas, highlighting a targetable vulnerability in cytokine-driven malignancies and bridging synthetic innovation with therapeutic discovery.
Confidence in the conduct and results of American elections has declined and polarized along party lines in recent years. Can a nonpartisan public information campaign featuring election officials enhance trust in elections when delivered to skeptical voters during a contentious political contest? We analyze a preregistered, randomized field experiment conducted during the 2024 US presidential election in which conservative voters were randomly assigned to a control condition or to receive a multimodal messaging campaign designed by political professionals explaining protections on election integrity. In contrast to the large positive effects of informational messages found in recent survey experiments, we observed primarily null effects with respect to turnout (n = 147,488), general confidence in elections (n = 4740 to 4868), and perceptions of the frequency of fraud (n = 4925). We observed one hypothesized effect: an increase in trust in the vote-by-mail process (n = 6438). This study provides rigorous evidence from a real public information campaign on election integrity, yielding effect sizes in the field that are much smaller than those observed in prior survey settings.
Pancreatic ductal adenocarcinoma (PDAC) is unresponsive to standard immunotherapies despite harboring cancer neoantigens capable of eliciting T cell responses. We completed two phase 1 clinical trials (NCT03956056 and NCT03122106) evaluating safety and immunogenicity of synthetic long peptide (SLP) and DNA personalized cancer vaccines (PCVs). PCVs were administered after resection and adjuvant chemotherapy. Tumor/normal whole-exome sequencing, RNA sequencing, and pVACtools were used to identify and prioritize candidate PCV neoantigens. PCVs were well tolerated without any grade ≥3 adverse events. Neoantigen-specific responses were demonstrated by interferon-γ enzyme-linked immunospot and intracellular cytokine staining. Expanded T cell receptor clonotypes were sequenced and transduced into autologous peripheral blood mononuclear cells to confirm neoantigen specificity. When compared with a contemporaneous institutional propensity-matched cohort, PCV patients demonstrated a trend toward prolonged median overall survival (4.4 versus 3.5 years, log-rank P = 0.23). Overall, PDAC PCVs are safe and feasible and elicit polyclonal T cell responses, linking prioritized cancer neoantigens to functional antitumor immunity.
