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bioRxiv2025

Decoding the epistemic arc: Distinct physiological signatures for curiosity, insight, understanding and liking during interactions with visual art

A series of internal states, proceeding from curiosity (drive state) to insight (uncertainty reduction) to pleasure (reward and reinforcement), might represent a fundamental pathway for motivated learning. Here we present a paradigm that combines measurement of curiosity, insight (aha), understanding and liking to outline the contours of this epistemic arc and trace their neuronal correlates. In two preregistered experiments we employ the "title effect" - the fact that additional semantic information can change how one understands and enjoys a piece of art. Participants viewed paintings and rated their curiosity for seeing the title. This was followed either by the original title or a dummy title lacking additional information, and a second presentation of the image, after which participants rated their strength of aha, aesthetic liking, and feeling of understanding the artwork. In a behavioral study (N=55 participants) we establish empirically that visual art with their titles can prompt strong feelings of aha. The association between ratings is complex and shaped by the type and amount of information in the stimuli; e.g. aha is linearly linked to liking and nonlinearly to understanding. In an EEG, ECG and eye tracking study with the same paradigm (N=49 participants) we use time-resolved decoding to trace the temporal sequence of processing. Understanding can be decoded from various (neuro)physiological correlates, over extended timespans. Robust decoding of curiosity both before and after the titles substantiates its relevance within the epistemic arc. Aha could be decoded from pupil size, but not from the EEG. Lastly, a fast initial EEG response was linked to aesthetic liking. Though much remains to explore, our study provides a new window into core behavioral and physiological properties of motivated information foraging.

neuroscience↗

bioRxiv2025

Physiological characterization in a somaclonal mutant for fruit shape derived from persimmon 'Hiratanenashi'

Fruit shape is an essential agronomic trait that contributes to the commercial value of fruit crops; however, the physiological mechanisms determining fruit shape have been studied only in a few model crops. Persimmon (Diospyros kaki Thunb.), a major fruit crop in East Asia, shows diversity in fruit shape among cultivars. The underlying molecular mechanisms that determine fruit shape remain unclear. A comparative physiological analysis was conducted to investigate the differences between a major Japanese cultivar, Hiratanenashi with a "flat" fruit shape, and its somaclonal mutant cultivar, Koushimaru with a "round" fruit shape. Through principal component analysis (PCA) with the elliptic Fourier descriptor, the fruit shape transitions in these two cultivars were measured over the fruit differentiation period (40-53 days after anthesis). Histological observation of the mesocarp cells in the fruit shape differentiation stage indicated that not only cell proliferation patterns but also multiple vectors involving cell shapes or sizes are possible determinants of differences in fruit shape. Transcriptome analysis at the fruit shape differentiation stage detected differentially expressed genes between the two cultivars. The hierarchical clustering with expression patterns throughout the fruit development/maturation stages defined four main clusters, including candidate genes determining fruit shapes. We focused on one of these genes, DKAch04a32073.t1, annotated as WUSCHEL related homeobox 13 (WOX13), which has been reported to be a key factor in callus formation (or stem cell proliferation) and the reconnection of organs in Arabidopsis thaliana. Future functional analyses of the candidate genes would provide a better understanding of the mechanisms underlying persimmon fruit shape.

plant biology↗

bioRxiv2025

The differentiation of myeloid progenitors is effected by cascading waves of coordinated gene expression that remodel cellular physiology in a characteristic sequence

The differentiation of hematopoietic progenitors into specialized types requires the transmittal of information from a few external or internal regulators to the thousands of genes that produce a cell types characteristic phenotypes. While the main signaling pathways, transcription factors, and the genes eliciting the terminal phenotypes are known, how information flows from a few regulators to thousands of genes to change the state of the cell remains to be fleshed out. To profile this information transfer process, we sampled the differentiation of the PUER myeloid cell line into macrophages and neutrophils at 29 time points over seven days. There is extensive transient regulation; the number of transcripts modulated in time is twice the number differentially expressed between endpoints. Differentiation is marked by two sharp transitions, at [~] 8h and [~] 80h, when transcriptomic state changes suddenly. We utilized non-negative matrix factorization to identify behaviors, characteristic temporal patterns of gene expression, and to classify transcripts by behavior. Only 10 distinct behaviors are sufficient to recapitulate the expression of [~]36,000 transcripts with high fidelity. Gene expression in most of the behaviors occurs in pulses of varying initiation times and durations. This implies that information transfer during differentiation occurs in cascading waves of gene expression culminating in the permanent turning on of certain genes after [~] 80h. Each behavior is enriched in specific biological processes, so that physiological remodeling proceeds in a characteristic order--signal transduction, translation and mRNA processing, metabolism, and, ultimately, myeloid phenotypic processes. The sharp transition at 8h corresponds to the completion of transcriptional and translational remodeling and the initiation of metabolic remodeling; the one at 80h corresponds to the elicitation of myeloid phenotypes. Our analysis shows that differentiation relies upon a series of transient, rapid, and complex gene regulatory events and highlights the importance of profiling it at a high temporal resolution. Author summaryThe maturation of hematopoietic progenitor cells into differentiated cell types occurs over a period of about a week. This process requires the progenitors to respond to external signals by changing the expression of thousands of genes to elicit the required phenotypes. We profiled how information is transferred from a few upstream regulators to thousands of genes by measuring genome-wide gene expression at high temporal resolution during white-blood cell differentiation. We show that the information transfer occurs in cascading waves, some as short as 8 hours and others lasting for 3 days, in which thousands of genes change expression coordinately. The physiological processes remodeled in each successive wave follow a characteristic order, starting with signal transduction pathways, followed by translation and mRNA processing, then metabolism, and culminating in the production of innate immunity phenotypes. Maturation is also punctuated with two sharp transitions, when genome-wide expression changes suddenly, associated with the initiation of metabolic remodeling and the production of terminal phenotypes. Our analysis shows that a complete description of differentiation requires the characterization of transient changes and not just those observable at the endpoints.

developmental biology↗

bioRxiv2025

Developmentally-specific physiological and metabolic responses support drought resilience in switchgrass and constrains biofuel yield

Switchgrass (Panicum virgatum) is a promising bioenergy crop due in part to its resilience to drought stress. However, the significance of drought timing remains poorly understood, both from a plant biology perspective and its impact on downstream biofuel production. This study determines the developmental stage-specific physiological and metabolic responses of switchgrass to drought stress and its implications for biofuel production using a custom-built programmable irrigation system. Vegetative, flowering, and senescence-stage drought significantly reduced CO2 assimilation, and stomatal conductance without affecting biomass yield. Metabolic profiling revealed significant accumulation of glucose, fructose, quinic acid, shikimate and GABA during vegetative-stage drought, while flowering and senescence stages exhibited limited metabolic changes. Similarly, specialized metabolites also displayed distinct developmental patterns, with vegetative-stage drought driving the most pronounced metabolic alterations. Thermochemically-treated and hydrolyzed switchgrass biomass from vegetative-stage drought showed elevated lignocellulose-derived compounds and saponins with the latter most positively correlating with fermentation lag times. Conversely, senescence-stage drought enhanced ethanol yields while lowering saponin levels in the hydrolysates. While vegetative-stage drought enhanced physiological resilience, it compromises downstream biofuel production by introducing fermentation inhibitors, particularly saponins.

plant biology↗

bioRxiv2025

Non-Physiological Potassium Concentrations in Commercial Culture Media Trigger Acute Epileptiform Activity in Human iPSC-Derived Neurons

Neuronal in vitro cultures are pivotal for studying brain electrophysiological function and dysfunction. Neuronal activity and communication are regulated by extracellular ion concentrations. Therefore, cell culture medium ion concentrations should ideally mimic those of cerebrospinal fluid (CSF) - considered as the milieu for brain cells in vivo. In this study, we demonstrate that commonly used cell culture media, including Neurobasal (+/- A), Neurobasal Plus, and BrainPhys media, do not accurately replicate human CSF ion concentrations. Using human iPSC-derived neuronal networks on microelectrode arrays, we show that the abnormally high potassium concentrations present in all tested cell culture media induce acute epileptiform activity, similar to that elicited by the convulsive drug 4- aminopyridine. These findings raise a critical question: How can human in vitro neuronal activity be defined as physiological and reliably distinguished from pathophysiological activity, if the routinely used ion concentrations in in vitro experiments are causing aberrant neuronal activity? SummaryThe neuronal activity in neuronal in vitro culture relies on extracellular ion concentrations, which should mimic cerebrospinal fluid (CSF). This study shows that common cell culture media and widely used artificial CSF composition in neuroscience research fail to replicate CSF ion levels, causing non-physiological and rather pathological neuronal activity.

neuroscience↗

bioRxiv2025

Host- and microbial-mediated mucin degradation differentially shape Pseudomonas aeruginosa physiology and gene expression

Pseudomonas aeruginosa is a hallmark pathogen of cystic fibrosis (CF) airway infections, capable of reaching high cell densities despite its limited ability to directly utilize mucin glycoproteins as a nutrient source. In the CF lung, however, P. aeruginosa may access preferred carbon sources (e.g., amino acids and short-chain fatty acids) through metabolic cross-feeding with co-colonizing mucin-degrading microbes. Although host-derived enzymes such as neutrophil elastase can also degrade mucins, the extent to which host-mediated mucin breakdown supports P. aeruginosa growth remains unclear. Thus, here we compared the nutritional impact of microbial versus host mucolytic activity on P. aeruginosa physiology. Analyses of CF sputum revealed patient-specific variability in mucin integrity that is shaped by both host and microbial factors. We demonstrate that mucin degradation by anaerobic bacteria through proteolysis, glycolysis, and fermentation, promotes robust P. aeruginosa growth, unlike mucin processed by neutrophil elastase alone. Targeted metabolomics identified acetate and propionate as key metabolites driving this cross-feeding, while transcriptomic and phenotypic analyses revealed that P. aeruginosa engages in diauxic growth on a broader set of mucin-derived substrates. Unexpectedly, cross-feeding with anaerobes triggered the induction of P. aeruginosa denitrification and fermentation pathways, suggesting redox remodeling despite being cultured under oxygen-replete conditions. Finally, the transcriptional profile of P. aeruginosa grown on anaerobe-conditioned mucins more closely resembled its in vivo gene expression, more so than when grown on intact or neutrophil-degraded mucins. Together, these findings provide new insight into the potential role of interspecies metabolic interactions in shaping pathogen physiology in the inflammatory, polymicrobial, and mucus-rich environment of the CF airways. Author SummaryCystic fibrosis (CF) airways contain viscous mucus that traps both pathogens and commensals. The major pathogen, P. aeruginosa thrives in these mucus-rich, inflamed environments, but how it acquires nutrients to sustain growth is poorly understood. We demonstrate that while host neutrophil enzymes degrade mucin polymers, this degradation alone does not provide substantial nutrients to support P. aeruginosa proliferation. In contrast, co-colonizing anaerobic microbiota extensively degrade mucins and generate short-chain fatty acids and other metabolites that strongly promote P. aeruginosa growth. We show that anaerobe-degraded mucins not only support faster growth but also trigger redox remodeling and gene expression changes that closely resemble P. aeruginosa behavior in CF patient sputum. This work highlights the important role of interspecies metabolic interactions in shaping CF airway infections and suggests new consideration for therapeutic strategies targeting airway microbiomes.

microbiology↗

bioRxiv2025

Recapitulating physiologically relevant oxygen levels and extracellular matrix remodeling in patient-derived tumor-immune tunable models reveal targeting opportunities for immunologically cold high-grade serous tumors

High-grade serous tumors are immunologically cold, characterized by limited immune cell infiltration and reduced clinical outcome, primarily due to hypoxia and extensive extracellular matrix remodeling that disrupt tumor-stromal-immune interactions. However, current experimental models fail to fully capture oxygen and matrix microenvironmental features, limiting progress in understanding tumor-immune dynamics and developing effective treatments. Here, we demonstrate that patient-derived tumor-immune tunable models, mimicking physiologically relevant oxygen levels and extracellular matrix remodeling, recapitulate the hypoxia-induced stromal/matrix dysregulation, which causes impaired immune infiltration, and enable dissecting targeted opportunities via TGF-{beta} signaling. The models integrate cancer cells co-cultured with cancer-associated fibroblasts and exposed to immune cells as multi-culture or challenged them to infiltrate into a 3D model bioengineered with autologous plasma from the matching patient or onto decellularized human ovaries. By bioengineering physiologically relevant oxygen levels of hypoxic tumors and physoxic ovaries, we uncovered that intratumoral hypoxia acts as a friend and a foe, causing hypoxia-induced stromal-driven impaired immune infiltration but enhancing the activation and cytotoxicity of CD8+ T cells. We also showed that targeting TGF-{beta} signaling reversed the hypoxia-induced stromal-driven impaired immune infiltration. These human-relevant tunable models may aid the development of targeted therapies to turn immunologically cold tumors into hot ones.

bioengineering↗

bioRxiv2025

Programmable microparticles rewire CAR signaling to enable super-physiological expansion of human T cells in vitro

T cell proliferative capacity and persistence critically determine the therapeutic success of chimeric antigen receptor (CAR) T cells. However, it remains unknown if and how human CAR-T cells can be externally programmed to reach maximal proliferative capacity. Here, we use programmable PLGA microparticles functionalized with CAR-antigens and CD28-costimulatory antibodies (CAREp) to repeatedly stimulate human CD8+ CAR-T cells in vitro. CAREp-stimulated CAR-T cells expanded continuously for over 100 days--versus [~]30 days with tumor cell stimulation--and achieved up to 1018-fold cumulative expansion, greatly surpassing CD3/28-Dynabeads. Early-phase transcriptomic responses-- upregulation of DNA repair, cell cycle, telomere maintenance, and mitochondrial pathways--aligned with long-term outcomes: massive proliferation, telomere stability, robust respiration, and preserved progenitor phenotype by single-cell sequencing. Differentiation and exhaustion signals were broadly suppressed. Transient telomerase activity further supported physiologic expansion. These findings demonstrate that nanoscale-controlled extracellular cues can rewire intracellular signaling to drive durable, super-physiological expansion of functional CAR-T cells.

immunology↗

bioRxiv2025

Predicting DNA origami stability in physiological media by machine learning

DNA origami nanostructures offer substantial potential as programmable, biocompatible platforms for drug delivery and diagnostics. However, their structural stability under physiological conditions remains a major barrier to practical applications. Stability assessment of DNA origami nanostructures has traditionally relied on image-based and empirical approaches, which are time-consuming and difficult to generalize across conditions. To address these limitations, we developed a machine learning approach for DNA origami stability prediction, based on measurable physicochemical parameters. Using dynamic light scattering (DLS) to quantify diffusion coefficients as a proxy for structural integrity, we characterized over 1400 DNA origami samples under varying physiologically relevant variables: temperature, incubation time, MgCl2 concentration, pH, and DNase I concentrations. The predictive performance of the model was confirmed using an independent set of samples under previously untested conditions. This data-driven approach offers a scalable and generalizable framework to guide the design of robust DNA nanostructures for biomedical applications.

bioengineering↗

bioRxiv2025

Study on physiological and ecological responses of alfalfa during the germination stage under drought, bicarbonate, and combined stress conditions

Alfalfa (Medicago sativa L.) is frequently constrained by drought and salinity during cultivation and production. This study aimed to investigate the differential response characteristics and underlying physiological and ecological mechanisms of alfalfa during the germination stage under drought stress, bicarbonate stress, and their combined effects. Twelve alfalfa varieties were subjected to germination tests using PEG-6000 to simulate drought stress (0-20%) and NaHCO{square} to simulate bicarbonate stress (0-30 mM). Based on the semi-inhibitory concentrations and phenotypic indices observed under single-stress conditions, a combined stress treatment was designed. The subordinate function method was employed to comprehensively evaluate the variations in stress responses among the twelve alfalfa varieties during the germination stage. Additionally, this study explored the physiological and ecological response mechanisms of drought-tolerant, salt-tolerant, and drought-salt-sensitive varieties. Among the 12 alfalfa varieties, WL363HQ has the strongest drought and salt tolerance, while WL319HQ is the most sensitive to drought and salt stress. Based on this, the varieties can be classified into drought-tolerant, salt-tolerant, and sensitive categories. At low concentrations, the drought-salt combination shows antagonism (salt alleviates drought inhibition); at high concentrations, it turns into synergy, and the inhibitory effect is amplified.WL363HQ adapts to the combined stress by maintaining stable SOD activity and gradually accumulating soluble sugar; WL319HQ shows sensitivity due to fluctuating SOD, membrane lipid peroxidation, and uncontrolled soluble sugar.

plant biology↗

bioRxiv2025

Local Mitochondrial Physiology Defined by mtDNA Quality Guides Purifying Selection

The mitochondrial genome (mtDNA) encodes essential subunits of the electron transport chain and ATP synthase. Mutations in these genes impair oxidative phosphorylation, compromise mitochondrial ATP production and cellular energy supply, and can cause mitochondrial diseases. These consequences highlight the importance of mtDNA quality control (mtDNA-QC), the process by which cells selectively maintain intact mtDNA to preserve respiratory function. Here, we developed a high-throughput flow cytometry assay for Saccharomyces cerevisiae to track mtDNA segregation in cell populations derived from heteroplasmic zygotes, in which wild-type (WT) mtDNA is fluorescently labeled and mutant mtDNA remains unlabeled. Using this approach, we observe purifying selection against mtDNA lacking subunits of complex III (COB), complex IV (COX2) or the ATP synthase (ATP6), under fermentative conditions that do not require respiratory activity. By integrating cytometric data with growth assays and simulations, we show that the decline of {Delta}atp6 mtDNA reflects both intracellular selection for intact genomes and a proliferative disadvantage of cells lacking ATP synthase. In contrast, loss of {Delta}cob and {Delta}cox2 mtDNA is primarily driven by selective maintenance of functional genomes. In heteroplasmic cells containing both intact and mutant mtDNA, fluorescent reporters revealed local reductions in ATP levels and membrane potential ({Delta}{Psi}) near mutant genomes, indicating spatial heterogeneity in mitochondrial physiology that reflects local mtDNA quality. Disruption of the respiratory chain by deletion of nuclear-encoded subunits (RIP1, COX4) abolished these physiological gradients and impaired mtDNA-QC, suggesting that local bioenergetic differences are required for selective recognition. Together, our findings support a model in which yeast cells assess local respiratory function as a proxy for mtDNA integrity, enabling intracellular selection for functional mitochondrial genomes.

cell biology↗

bioRxiv2025

Highly and lowly domesticated endangered fish from a conservation hatchery diverge in their thermal physiology, transcriptome, and methylome

Conservation hatcheries aim to produce fish for supplementation of wild populations, but hatchery environments may drive phenotypic divergence from wild fish. These diverged traits may have reduced fitness in the wild, which could compromise wild population sustainability and evolutionary potential, such as in response to climate change. Delta smelt are a critically endangered fish species that are safeguarded against extinction with a hatchery refuge population. We investigated whether elevated rearing temperature through larval development adjusted upper thermal tolerance limits (acclimation) in Delta smelt, whether upper thermal tolerance and plasticity (acclimation ability) differed between fish with old or recent hatchery ancestry (high or low domestication index; DI), and temperature and DI effects on liver transcriptome and methylome patterns. We observed that elevated rearing temperatures induced higher thermal tolerance (acclimation). Individuals with higher DI also had higher upper thermal tolerances, but high DI families had reduced thermal plasticity between rearing temperatures. This is consistent with domestication causing heritable elevation of upper thermal tolerance but at the cost of reduced thermal plasticity. High and low DI fish were differentiated in both genetic variation and methylome variation, suggesting the influence of both during domestication. But methylome differences distinguishing high and low DI fish did not overlap with temperature-induced methylome changes, and do not appear to be stably inherited in the hatchery. We conclude that domestication selection has altered thermal physiology within the refuge hatchery despite careful genetic management, underpinned by shifts in the transcriptome and methylome. These changes could affect Delta smelt fitness upon reintroduction to habitats that continue to warm, and show that physiological traits can diverge even within carefully genetically managed hatchery populations.

evolutionary biology↗

bioRxiv2025

Pro-coagulant lipids in physiological ratios found in the activated platelet membrane do not impact clot structure or fibrinolysis in purified assays.

PurposeA central role for the pro-coagulant membrane comprising aminophospholipids (aPL) and enzymatically oxidized phospholipids (eoxPL) in promoting hemostasis via interaction with coagulation factor Gla domains is well established. However, little is known about their interactions with the fibrinolytic pathway, their ability to alter clot structure or to support the activated protein C (APC) pathway. Previous studies used membrane liposome compositions that differ from those expected physiologically and/or generated inconsistent findings. To address this, pro-coagulant membranes comprising physiological proportions of aPL and eoxPL will be tested for their ability to support fibrinolysis using standard assays. MethodsThe impact of phospholipids on clot structure and clot lysis was tested using absorbance-based assays. To investigate the impact of PS or eoxPL on fibrinolysis, plasmin was monitored chromogenically, and clot dissolution measured in a purified lysis system activated by tissue plasminogen activator or urokinase. To determine the impact of eoxPL on APC/protein S, FVa was incubated with APC (+/-protein S) in a purified prothrombinase assay. ResultsAt the concentrations of lipids tested in our study, PS did not significantly impact clot structure or fibrinolysis. Similarly, eoxPL did not impact either fibrinolysis or activity of APC/Protein S. ConclusionUsing liposome compositions that approximate activated blood cells, we found that the pro-coagulant membrane is unlikely to influence either clot structure or fibrinolytic activity directly, beyond its well characterized role in supporting Gla dependent coagulation factors and the actions of platelet associated proteins/receptors.

pharmacology and toxicology↗

bioRxiv2025

HCN channels reveal conserved and divergent physiology in supragranular pyramidal neurons in primate species

The physiological properties of human and rodent neurons differ, yet the extent to which these differences reflect human specializations is often unclear. Compared with their rodent counterparts, human supragranular pyramidal neurons possess enriched HCN-channel-dependent intrinsic membrane properties and a related sensitivity to synaptic inputs containing delta/theta band frequencies. We tested whether other primate species possess enriched HCN-channel dependent membrane properties. We found ubiquitous HCN1 subunit gene expression in supragranular glutamatergic neurons across New World Monkeys, Old-World Monkeys, and great apes in single nucleus RNA-sequencing datasets. Using Patch-seq recordings from acute and cultured brain slices, we found robust HCN-dependent physiological properties in supragranular pyramidal neurons in a species of New-World monkey (Saimiri sciureus) and two species of Old-World Monkey (Macaca mulatta, Macaca nemestrina). In both human and macaque neocortex, HCN-related intrinsic properties increased in magnitude with increasing laminar depth, especially in one transcriptomic cell type. Within this type, HCN dependent properties were more pronounced in macaque than human neurons. These findings indicate that HCN-governed membrane properties and sensitivity to delta/theta band frequencies are roughly conserved in supragranular pyramidal neurons across at least 36 million years of primate evolution.

neuroscience↗

bioRxiv2025

A Computational Pipeline for Physiologically Informed Calibration of Ligand Reaction-Diffusion Models Using High-Throughput Sequencing

All physiological processes fundamentally rely on continuous cellular cross-talk to maintain organization and ensure proper function. Among the various modes of cellular communication, ligand-mediated chemical signaling, in which a ligand is secreted by one cell, diffuses through the extracellular environment, and binds to a receptor on another (or the same) cell to elicit a downstream response, is arguably the most ubiquitous and foundational. Given its importance, numerous mathematical models have been developed to describe this reaction-diffusion mechanism, capturing ligand secretion, diffusion, decay, and binding under both normal and pathological conditions. However, parameter calibration for such models often lags behind model development. This is due to limited data that faithfully represent the biological microenvironment, as well as due to the absence of a robust, rigorous framework to integrate available data into the mathematical model. To address this gap, we propose that transcriptomics (gene expression) data, namely the combination of single-cell RNA sequencing and spatial transcriptomics, provide a rich, increasingly abundant, and underutilized source of information that can be used to calibrate the parameters of the cellular reaction-diffusion models at the larger mesoscopic scale. To this end, we develop a computational pipeline that leverages these data to extract parameter values for reaction-diffusion models, and illustrate its application through two human wound-healing case studies. Using open-source transcriptomics data, we calibrate the reaction-diffusion model parameters of the isoforms of Transforming Growth Factor Beta (TGF{beta}), a signaling molecule central to tissue repair and development as well as to pathological processes such as cancer and fibrosis. Our pipeline integrates traditional numerical (finite volume) solvers for the ligand concentration fields with bioinformatics, machine learning, and Bayesian inference methods, combining existing and novel computational tools into a single framework for a physiologically informed, data-driven parameter calibration process. The pipeline is modular, allowing easy extension or adjustment depending on user needs. Overall, this framework facilitates rigorous model calibration, an essential step toward ensuring that mathematical models have meaningful research and potential translational utility.

systems biology↗

bioRxiv2025

Physiological and Metabolic Responses of Chickpea to Post-Flowering High Temperatures and Limited Water Availability

Post-flowering elevated temperatures are increasingly frequent and strongly affect crop yield and seed nutritional quality. This study examined the impact of elevated post-flowering temperatures (32{degrees}C/25{degrees}C, day/night) combined with two watering regimes (40% and 10% field capacity) on chickpea genotypes. Elvar and Electra, top-yielding Portuguese genotypes well adapted to southern Portugals dry climate were evaluated. Under controlled high-temperature conditions (Phenolab), reproductive cycle was shortened to 30-35 days, compared with 65 days under greenhouse conditions (24{degrees}C/18{degrees}C). Water use peaked soon after flowering and declined after 19 days, regardless of genotype or watering regime, suggesting a physiological limitation on water use. Elevated temperature strongly reduced seed number and weight while altering composition. Nutrient density improved, with higher protein and mineral levels (P, Mg, S, Mo, Fe, Zn) and lower starch content, highlighting a consistent protein-starch trade-off unaffected by water availability. While growth environment largely determined composition, enzymatic activity patterns revealed genotype-specific differences in carbon metabolism (e.g. sucrose synthase, cell wall invertase, aldolase and phosphoglucose isomerase). Overall, these findings suggest genotype-specific responses driven by carbon metabolism and emphasize integrating metabolic, physiological and composition traits in breeding for yield stability and nutritional value. HighlightPost-flowering temperature dictates reproductive duration and seed composition, enhancing nutritional density but lowering yield. Protein-starch trade-off was consistent across genotypes, while enzymatic activity profiles enabled genotype discrimination under contrasting environments.

plant biology↗

bioRxiv2025

Bioengineered iPSC Vessels Recapitulate Human Vascular Physiological Function and Aging Phenotypes

Vascular aging contributes to multisystem diseases and limits health span. Although various animal models have contributed to aging research, their vasculatures poorly recapitulate human physiology. Even existing tissue-engineered blood vessels fail to mimic human vascular function and pathology, hindering translational advances in vascular aging studies. Here, we present a novel human physiological vascular model fabricated via the unique molding-induced circumferential alignment of human induced pluripotent stem cell (iPSC)-derived vascular smooth muscle cells with luminally seeded endothelial cells. This architecture enabled dynamic vasodiameter changes in response to vasoactive stimuli, including hormones and intraluminal pressure. Using iPSCs from a patient with Werner syndrome, the model recapitulated aging-associated phenotypes, such as hypercontractility and increased vascular compliance, possibly due to impaired nitric oxide bioavailability. Transcriptomic and metabolomic analyses revealed age-related dysregulation consistent with vascular senescence. As a key advantage of the vasculature, spatial transcriptomic analysis demonstrated upregulation of the aging marker CDKN1A near the lumen and downregulation of COL6A1 and TPM1 throughout the vessel. Treatment with mitochonic acid 5, a mitochondria-targeted compound, significantly reversed the aging phenotypes. These findings demonstrate that our engineered vascular model recapitulates key aspects of human vascular properties and provides a platform for mechanistic studies of vascular aging and drug discovery aimed at extending health span.

bioengineering↗

bioRxiv2025

Interactions of the LINE-1 encoded ORF1p with proteins and chromatin converge on a role in neuronal physiology

Retrotransposons are emerging as novel regulators of embryonic and brain development. We recently demonstrated that the LINE-1-encoded protein ORF1p is abundantly expressed in adult mouse and human neurons, although its function remains unclear. Here, we characterize the ORF1p interactome in differentiated mouse and human neurons using mass spectrometry and identify novel partners implicated in gene regulation and neuron-specific processes. ORF1p localizes not only to neuronal nuclei, where it associates with chromatin under steady-state conditions, but also to neurites, supporting a role in neuronal physiology. To further explore its nuclear functions, we sorted human post-mortem neurons with high or low nuclear ORF1p levels and performed ORF1p knockdown in cultured human neurons, followed by chromatin accessibility assays. Both approaches revealed consistent patterns of differential chromatin accessibility dependent on ORF1p. Loss of ORF1p also led to the downregulation of long, neuron-specific genes and altered neurite morphology. Together, these findings point to a physiological role of ORF1p in post-mitotic neurons, mediated through converging interactions with proteins and chromatin.

neuroscience↗