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Search indexed bioRxiv preprints in genomics, neuroscience, cell biology and bioinformatics. Read source abstracts and check manuscript versions; preprints are not peer reviewed.

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At least 343 records · Page 19Linked to original sources

bioRxiv2025

Sleep increases propagation speed of physiological brain pulsations

During sleep, there is an increase in the brain cerebrospinal fluid (CSF) solute convection driven by physiological pulsations. Although the main drivers of CSF flow, namely cardiac, respiratory, and vasomotor pulsations, become more powerful during sleep, there is relatively little information regarding their effects on CSF flow velocity across human brain during sleep. Here, we used functional magnetic resonance encephalography (MREG) to measure non-invasively changes in brain water flow during to sleep by tracking the propagating ultrafast signal changes induced by physiological brain pulsations. We first undertook a phantom study confirming that dense optical flow analysis of MREG data accurately detects water flow velocity, and reflects the power of the physiological pulsations. We then applied the method to quantify CSF water flow velocity in brain of healthy volunteers during EEG-verified awake and sleep recordings of ultrafast MREG data. Sleep induced an increase in CSF flow speed, as demonstrated by elevated vasomotor and respiratory pulsation speeds, while the speed of cardiovascular impulse propagation remained unchanged. The speed increases match previous findings of respective pulsation power changes, and correlated with slow delta EEG power. The sleep-induced CSF flow speed increases occurred dynamically over both pulsation cycles, without the large effects on flow directions reported previously in several neurological conditions. In conclusion, sleep increases 3D water flow speed dynamically in human brain regions showing concomitant pulse power increases, supporting a porous media model of hydrodynamics in brain cortex.

neuroscience↗

bioRxiv2025

Characterizing venom resistance in Monodelphis domestica yields new insights into mammalian blood physiology

Interactions between predators and prey are often characterized by strong selection pressures that shape extreme physiological adaptations. Venom resistance in large-bodied South American opossums (Clade Didelphini) is a striking example, as these marsupials prey on venomous snakes and exhibit remarkable resistance to their venom. While resistance is well documented in Didelphini, relatively little is known about venom resistance in the smaller, more diverse members of Didelphidae, which inhabit the same regions and encounter the same predators. Here, we investigate venom resistance in the small-bodied opossum, Monodelphis domestica, through multi-level physiological assays, examining responses to purified venom components and whole venom from sympatric and allopatric vipers. Our results show M. domestica resists venom-induced disruptions to blood coagulation, retains platelet function in the presence of platelet-disrupting venoms, and inhibits snake venom metalloproteinases. Unexpectedly, we find that M. domestica von Willebrand Factor (VWF) requires increased shear force to elongate, a previously unknown aspect of opossum blood physiology that may contribute to venom resistance and may have relevance to human coagulopathies. These findings expand the extent of venom resistance beyond large-bodied Didelphini, suggesting it is a widespread trait in South American marsupials and providing new insights into venom-mammal coevolution. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=140 SRC="FIGDIR/small/634112v2_ufig1.gif" ALT="Figure 1"> View larger version (67K): org.highwire.dtl.DTLVardef@1efb74forg.highwire.dtl.DTLVardef@ebcb82org.highwire.dtl.DTLVardef@7ddef2org.highwire.dtl.DTLVardef@1b81569_HPS_FORMAT_FIGEXP M_FIG C_FIG

evolutionary biology↗

bioRxiv2025

Phenotypic integration of post-germination traits in Quercus suber: morphological development is mediated by acorn mass; leaf physiology by populations aridity.

Background and AimsAssessing intra-specific trait covariation across populations is essential to understand species adaptive responses to climatic variation. However, in tree species, this is understudied for early-life stages despite they are more vulnerable to environmental changes and that climatic adaptations can differ between tree ages. In this paper, we studied the integrated phenotype of Quercus suber during the months following germination. For that, we studied the covariation of key traits involved in seedlings water and C economies along a gradient of aridity at seed origin. MethodsWe performed a provenance trial with 157 Q. suber seedlings originating from 7 different populations across the species distribution. The seedlings were germinated and grown during 4 months under common conditions. Acorn mass along with 11 above- and below-ground traits involved in water and C use were measured. Their covariation in response to aridity at seed origin was analyzed using structural equation modelling (SEM). The variation of individual traits to increasing aridity and the mediation of acorn mass was also tested. Key ResultsSeedlings from arid populations displayed higher leaf evaporative demand coupled with a greater root water uptake capacity. Their leaf physiology also depicted a greater C acquisition capacity, strongly linked to traits conferring drought and heat tolerance. The development of above- and below-ground tissues responded mainly to acorn mass, whereas leaf physiology variations were associated to populations aridity. ConclusionsDry-origin seedlings display a more acquisitive strategy at the whole-plant level compared with seedlings from mesic provenances. This allows a greater water and carbon uptake capacities following germination, which is critical for their survival during their first summer. Leaf physiology adjustments to populations climate contrasts with its plasticity observed by other studies addressing juvenile trees, highlighting Q. suber varying adaptive strategies at different life stages.

ecology↗

bioRxiv2025

Polymer-assisted assembly of giant vesicles in physiological solutions

Thin film hydration methods are widely used to assemble giant unilamellar vesicles (GUVs), but their efficiency drops sharply in solutions of physiological ionic strength due to enhanced adhesion between stacked lipid bilayers, which suppresses bud and foam-like mesophase formation. Here, we introduce polymer-coated nanocellulose paper (PCP) as a nanostructured substrate that overcomes this limitation. Hydration of lipid films on PCP--termed PCP-assisted hydration-- achieves high GUV yields across a broad temperature range (4-45 {degrees}C) using diverse soluble polymers, including ultralow-gelling agarose, hyaluronic acid, dextran, carrageenan, and polylysine. The nanoscale curvature of the cellulose fibers and the osmotic pressure generated by polymer dissolution act synergistically to promote membrane budding even under physiological salt conditions. The approach is scalable--supporting GUV production from millimeter-sized pieces to large-format sheets--and biocompatible, enabling encapsulation of complex biochemical systems such as cell-free expression mixtures and actin-fascin assemblies. PCP-assisted hydration thus provides a robust, versatile, and high-yielding platform for generating functional GUVs under physiological conditions.

biophysics↗

bioRxiv2025

Temporal analysis of physiological phenotypes identifies novel metabolic and genetic underpinnings of senescence in maize

Leaf senescence induces extensive metabolome reprogramming to optimize nutrient recycling, enhance resilience to abiotic and biotic stress, and improve productivity. However, the characterization of these metabolic shifts and the identification of key metabolites and pathways remains limited. We generated a temporal map of physiological and metabolic diversity in genetically diverse maize inbred lines varying for the staygreen trait. Combinatorial analysis of physiological and metabolic changes revealed substantial metabolic perturbations and identified 84 leaf metabolites associated with senescence. Non-staygreen inbred lines exhibited higher accumulation of primary metabolites including sugar alcohols such as mannitol and erythritol, and amino acids such as phenylalanine and arginine. In contrast, the staygreen inbred lines showed higher abundance of secondary metabolites, primarily phenylpropanoids, including caffeic acid, chlorogenic acid, and eriodictyol. Linking metabolome to the genome identified 56 novel candidate genes expressed in adult maize leaf that regulate metabolic flux during senescence. Reverse genetic analysis validated the role of naringenin chalcone and eriodictyol in both maize and Arabidopsis, demonstrating a conserved function of these phenylpropanoids in leaf senescence across monocots and dicots. Our study provides valuable insights into the coordinated physiological and metabolic changes driving leaf senescence and identifies novel genes underlying this complex developmental process.

plant biology↗

bioRxiv2025

Qualitative and Quantitative Comparative Analysis of Common Normal Variants and Physiological Artifacts in MEG and EEG

AbstractMagnetoencephalography (MEG) and electroencephalography (EEG) provide complementary insights into brain activity, yet their distinct biophysical principles influence how normal neurophysiological patterns and artifacts are represented. This study presents a comprehensive qualitative and quantitative analysis of common physiological variants and artifacts in simultaneously recorded MEG and EEG data. We systematically examined patterns such as alpha spindles, sensorimotor rhythms, sleep-related waveforms (vertex waves, K-complexes, sleep spindles, and posterior slow waves of youth), as well as common artifacts including eye blinks, chewing, and movement-related interferences. By applying time-domain, time-frequency, and source- space analyses, we identified modality-specific differences in signal representation, source localization, and artifact susceptibility. Our results demonstrate that MEG provides a more spatially focal representation of physiological patterns, whereas EEG captures broader, radially oriented cortical activity. Mutual information analysis indicated that MEG-derived independent components exhibited greater topographical variability and higher information content for neurophysiological activity, while EEG components were more homogeneous. Signal-to-noise ratio (SNR) analysis confirmed that MEG gradiometers capture the highest total information, followed by magnetometers and then EEG. Notably, physiological signals such as vertex waves and K-complexes exhibited significantly higher total information in MEG, whereas EEG was more sensitive to high-amplitude artifacts, including swallowing and muscle activity. These findings highlight the distinct strengths and limitations of MEG and EEG, reinforcing the necessity of multimodal approaches in clinical and research applications to improve the accuracy of neurophysiological assessments.

neuroscience↗

bioRxiv2025

An unsuspected physiological role for mGluRIII glutamate receptors in hippocampal area CA1

Group III metabotropic glutamate receptors (mGluRIII) are expressed broadly throughout the neocortex and hippocampus but are thought to inhibit neurotransmitter release only at a subset of synapses and in a target cell- specific manner. Accordingly, previous slice physiology experiments in hippocampal area CA1 showed that mGluRIII receptors inhibit glutamate and GABA release only at excitatory and inhibitory synapses formed onto GABAergic interneurons, not onto pyramidal cells. Here, we show that the supposed target cell-specific modulation of GABA release only occurs when the extracellular calcium concentration in the recording solution is higher than its physiological concentration in the cerebrospinal fluid. Under more physiological conditions, mGluRIII receptors inhibit GABA release at synapses formed onto both interneurons and pyramidal cells but limit glutamate release only onto interneurons. This previously unrecognized form of mGluRIII-dependent, pre-synaptic modulation of inhibition onto pyramidal cells is accounted for by a reduction in the size of the readily releasable pool, mediated by protein kinase A and its vesicle-associated target proteins, synapsins. Using in vivo whole-cell recordings in behaving mice, we demonstrate that blocking mGluRIII activation in the intact CA1 network results in net effects consistent with decreased inhibition and significantly alters CA1 place cell activity. Together, these findings challenge our current understanding of the role of mGluRIII receptors in the control of synaptic transmission and encoding of spatial information in the hippocampus.

neuroscience↗

bioRxiv2025

Physiological and functional characterization for high-throughput optogenetic skeletal muscle exercise assays

Exercise has long been considered an essential part of human health and longevity. Recent physiological studies have expanded muscles role beyond simply acting as an actuator, revealing muscles exercise-mediated paracrine and endocrine relationships with other organ systems. In vitro engineered skeletal muscle models can address physiological questions about exercise adaptation with the precision of cell biology. Optogenetic tools have enabled a noninvasive approach to stimulating muscle contraction that avoids the potential off-target effects of electrical stimulation techniques. In this article we propose high-throughput culture and optical exercise protocols to generate statistically robust cellular exercise response datasets. We characterize optical rheobase for 2D muscle tissue morphology, finding that optical intensities as low as 5 W mm-2 can trigger contraction. We then analyze bulk RNA sequencing data collected from high throughput, acute exercise protocols and find a rich display of transcriptional behavior that is consistent with experimental observations. The spontaneous contractility of our tissue constructs introduced oxygen diffusion challenges when maintained in a 24 well plate, and our analysis shows divergent myogenic and pathological transcriptional consequences of hypoxia. We believe our techniques provide a practical foundation for conducting future high-precision in vitro exercise studies of skeletal muscle. Translational impactHigh-fidelity, engineered skeletal muscle has potential to elucidate exercise-mediated response pathways at the cell and tissue level. We leverage optogenetic techniques to develop a high-throughput assay that optically stimulates 2D muscle monolayers, avoiding potential cell damage from electrical stimulation. Our culture and exercise protocol generates statistically robust RNA sequencing datasets which reveal myogenic and pathological responses to exercise and in vitro culture conditions, informing practical next steps to cultivate stronger, more physiologically relevant muscle models.

bioengineering↗

bioRxiv2025

Fecal proteomics of wild capuchins reveals impacts of season, diet, age, and, sex on gut physiology

Understanding how the physiology of free-ranging mammals is impacted by environmental stressors is a major focus of ecological research. However, the constraints of non-invasive sampling pose serious challenges to the acquisition of physiological data from most species of primates. As a result, little is known about how the gut responds to ecological stimuli at the cellular level in wild populations. Recent research has demonstrated that proteomics could fill this knowledge gap by sequencing and quantifying proteins directly from primate feces. In order to ascertain how the gut of free-ranging white-faced capuchin monkeys (C. imitator) is influenced by environmental heterogeneity, diet, age, and sex, we sequenced 45 fecal proteomes from 24 individuals from the Sector Santa Rosa population in Costa Rica, using liquid chromatography-tandem mass spectrometry with label-free quantification. Fecal proteins assigned to C. imitator were strongly localized to gut tissues and functionally enriched for digestive and immune functions. We identified 41 capuchin candidate proteins linked to seasonality, age, sex, and diet. We also quantified abundances of dietary fruit, dietary insects, helminth gut parasites, and gut microbes. Our results demonstrate the viability of using quantitative fecal proteomics in free-ranging populations of mammals to integrate host physiology, diet, and microbial ecology through non-invasive means.

ecology↗

bioRxiv2025

Seasonal changes in the physiology and metabolism of grapevine perennating buds

Grapevine (Vitis vinifera L.) buds undergo seasonal dormancy to survive unfavourable conditions and synchronize growth with environmental cues. While dormancy transitions have been widely studied in temperate woody perennials, the physiological and metabolic dynamics underlying these transitions in grapevine remain poorly understood. Our study investigates seasonal changes in the physiology and metabolism of perennating buds in V. vinifera cv. Cabernet Sauvignon, focusing on dormancy depth, respiration, sugar metabolism, and cell cycle activity. We identified three distinct phases of bud quiescence: (i) para-dormancy (early summer), characterized by active metabolism and high levels of tricarboxylic acid cycle intermediates, shikimate, and myo-inositol; (ii) endo-dormancy (late summer to autumn), where dormancy depth peaked in late summer and was marked by reduced respiration and bud water content, and a sharp decline in hexose levels with a concomitant increase in raffinose; and (iii) eco-dormancy (winter to spring), featuring increased respiration, sugar mobilization (notably sucrose, glucose, and trehalose), and reactivation of cell division, with a shift of cells into the G2 phase. Just prior to bud burst, we observed a significant accumulation of sugar-phosphates, providing evidence that supports their role in promoting bud burst also in grapevine. Our findings provide new insights into the biochemical and physiological regulation of bud dormancy and bud burst, contributing to a deeper understanding of dormancy transitions in perennial crops.

plant biology↗

bioRxiv2025

A naturally occurring urinary collagen type I alpha 1-derived peptide inhibits collagen type I-induced endothelial cell migration at physiological concentrations

Collagen type I (COL(I)) is a key component of the extracellular matrix (ECM) and is involved in cell signalling and migration through cell receptors. Collagen degradation produces bioactive peptides (matrikines), which influence cellular processes. In this study, we investigated the biological effects of nine most abundant, naturally occurring urinary COL(I)-derived peptides on human endothelial cells at physiological concentrations, using cell migration assays, mass spectrometry-based proteomics, flow cytometry, and AlphaFold3. While none of the peptides significantly altered endothelial migration by themselves at physiological concentrations, full-length COL(I) increased cell migration, which was inhibited by Peptide 1 (229NGDDGEAGKPGRPGERGPpGp249). This peptide uniquely contains the DGEA and GRPGER motifs, interacting with integrin 2{beta}1. Flow cytometry confirmed the presence of integrin 2{beta}1 on human endothelial cells, and AlphaFold3 modelling predicted an interaction between Peptide 1 and integrin 2. Mass spectrometry-based proteomics investigating signalling pathways revealed that COL(I) triggered phosphorylation events linked to integrin 2{beta}1 activation and cell migration, which were absent in COL(I) plus peptide 1-treated cells. These findings identify Peptide 1 as a biologically active COL(I)-derived peptide at a physiological concentration capable of modulating collagen-induced cell migration, and provide a foundation for further investigation into its mechanisms of action and role in urine excretion.

cell biology↗

bioRxiv2025

A genetic model for development, physiology and behavior of zebrafish larvae devoid of catecholamines

Dopamine and noradrenaline have conserved roles in control of physiology and behaviors of vertebrates. However, vertebrate genetic systems completely devoid of catecholamines are not available. We have generated a genetic zebrafish model completely devoid of catecholamines by combining mutations in all three genes involved in L-DOPA synthesis: the tyrosine hydroxylase genes th and th2, and tyrosinase tyr. We found catecholamine-deficient zebrafish larvae to be viable and to develop an anatomically normal nervous system including catecholaminergic neuron somata and projections, albeit with reduced cell numbers detected in some clusters. In contrast, selected physiological functions that depend on catecholamines are impaired, including hatching and heart rate regulation upon temperature challenges. Spontaneous locomotion and optomotor behaviors are also impaired. Despite the changes observed, it is surprising that larvae develop a largely normal behavioral repertoire. Our model will be useful to investigate how physiology and neural circuit function are regulated in catecholamine deficient larvae.

developmental biology↗

bioRxiv2025

Allele-Specific Effects of Mutations in the Rifampin Resistance-Determining Region (RRDR) of RpoB on Physiology and Antibiotic Resistance in Enterococcus faecium

Enterococcus faecium is a member of the human gut microbiota that has evolved into a problematic nosocomial pathogen and leading cause of infections in hospitalized patients. Treatment of E. faecium infections is complicated by antibiotic resistance, making it important to understand resistance mechanisms and their broader consequences in this pathogen. Here we explored the collateral effects of rifampin resistance-associated mutations in the E. faecium RNA polymerase {beta}-subunit (RpoB). Of 14,384 publicly available E. faecium genomes, nearly one-third carried a mutation in the rifampin resistance-determining region (RRDR) of RpoB. In a local population of 710 E. faecium clinical isolates collected from patients at a single hospital, we found significant associations between the presence of RRDR mutations and prior exposure to rifamycin antibiotics, as well as associations between RRDR mutations and altered daptomycin susceptibility. To investigate the phenotypic impacts of RRDR mutations, we generated and studied four isogenic strains with distinct RRDR mutations (Q473K, G482D, H486Y, S491L) that overlapped with clinical isolate variants. Transcriptomic and phenotypic analyses revealed allele-specific effects on E. faecium gene expression, growth dynamics, antibiotic susceptibility, isopropanol tolerance, and cell wall physiology. One frequently observed mutation, H486Y, caused minimal transcriptional changes and enhanced bacterial fitness under antibiotic stress. In contrast, the S491L mutation induced extensive transcriptional changes and slowed bacterial growth, but also conferred increased isopropanol tolerance, potentially enhancing bacterial survival in the hospital. Overall, our findings highlight the multifaceted impacts of RRDR mutations in shaping E. faecium physiology and antibiotic resistance, two important features of this hospital-associated pathogen. ImportanceUnderstanding how antimicrobial resistance affects bacterial physiology is critical for developing effective therapeutics against bacterial infections. In this study, we found that rifampin resistance-associated mutations in RpoB are widespread in Enterococcus faecium, a leading multidrug-resistant pathogen. By studying isogenic wild-type and RpoB mutant strains, we discovered that RpoB mutations, while conferring resistance to rifampin, have distinct allele-specific effects on other bacterial phenotypes. Some of these collateral effects appear to promote E. faecium resistance to antibiotics and survival in the hospital environment, raising questions about the selective pressures driving their emergence. Overall, our study underscores the importance of examining the collateral effects of resistance-associated mutations in multidrug-resistant pathogens, which could help mitigate their persistence and spread among vulnerable patients.

microbiology↗

bioRxiv2025

Evaluation of Morpho-physiological Traits of F1 Hybrids and Estimation of Standard Heterosis of Sweet Pepper (Capsicum annuum L.) in Sylhet

Sweet pepper (Capsicum annuum L.) is a highly demanded crop valued for its culinary and nutritional benefits. This study aimed to evaluate the morphological, physiological, and yield-contributing traits of developed hybrids and check varieties, as well as estimate standard heterosis. The experiment was conducted at the Horticulture Department, Sylhet Agricultural University, from October 2022 to June 2023, using eight hybrids (P3xP1, P4xP3, P6xP5, P5xP1, P7xP1, P5xP3, P3xP2, and P6xP3) and two check varieties (CV1 and CV2). The field and laboratory experiments followed RCBD and CRD designs, respectively, with three replications. Significant morphological variations were observed in growth habit, leaf shape, flower position, fruit color, size, and nodal anthocyanin. The hybrids P5xP1, P7xP1, P6xP5, P3xP2, and P5xP3 exhibited superior morphological, physiological, and yield traits compared to check varieties. Earliness in flowering (30.33 days) and fruit setting (38.33 days) was recorded in P3xP1. Maximum fruit length (13.57 cm) was observed in P5xP1, while the highest fruit diameter (8.71 cm) and individual fruit weight (214.51 g) were found in P3xP2. The highest fruit yield per plant (1.94 kg) and per hectare (61.98 kg) was recorded in P5xP1. Positive standard heterosis was observed for key traits over check variety and mostly developed hybrids showed better performance in all traits compared to check variety. Pearson correlation and PCA analysis revealed key trait associations and genetic variation among sweet pepper hybrids, aiding breeding strategies. Considering morphological, physiological, yield potential and heterosis, P5xP1, P7xP1, P6xP5, P3xP2, and P5xP3 are recommended for further evaluation and breeding programs.

plant biology↗

bioRxiv2025

Cryoprotectants-assisted plunge freezing of thick brain tissue specimens for targeted physiologically relevant cryo-imaging in situ

In situ cryoET (cryoelectron tomography) and cryo-FIB/SEM (cryo-focused ion beam/scanning electron microscopy) volume-EM (electron microscopy) imaging provide spatiotemporal snapshots of biological systems in their near-native aqueous environment. Freezing and subsequent thinning of thick biological specimens prior to cryo-imaging is a time-consuming and challenging task that requires state-of-art methodology. As a result, cryo-imaging reports obtained from non-trivial specimens including mammalian brain tissues are scarce and their physiological relevance remains to be determined. Here, we benchmarked plunge freezing with a variety of cryoprotectants that allow for mouse brain tissue vitrification of up to about 100 microns thick and across several brain regions while keeping the tissue functional. By utilizing the knock-in (KI) mouse model with fluorescent astrocytes we have performed targeted cryo-FIB/SEM volume-EM imaging as well as targeted high-resolution cryoET imaging. Prior to cryoET, we have successfully generated lamellae in a semi-automated fashion on both LMIS (liquid metal ion source)- and plasma-based cryo-FIB/SEM instrumentation thus expanding applicability of our pipeline. We visualized the NVU (neurovascular unit) and astrocytes processes and validated the physiological relevance of our outputs based on the morphology of the corresponding cellular and subcellular features. The pipeline utilizes common vitrification setups and can be potentially extended toward alternative tissue specimens. Ultimately, we expect our approach to become an important step towards democratization of physiologically relevant in situ cryo-imaging studies.

biophysics↗

bioRxiv2025

Modeling physiological insulin sensitivity and pre-diabetic insulin resistance in multiple hPSC-derived cell types

Recently, we demonstrated the development of a human pluripotent stem cell (hPSC)-derived adipocyte (fat cell) model with physiological insulin signaling. For the first time, a human in vitro adipocyte cell model has an insulin response similar to in vivo human adipocytes. We next leveraged this protocol to study the early stages of insulin resistance preceding Type 2 Diabetes, by exposing these cells to diabetic patient levels of hyperinsulinemia. This resulted in mild insulin resistance on all of the aforementioned phenotypes, reminiscent of early T2D development in humans. This is a powerful model to study the mechanisms of T2D development and the underlying molecular pathology. However, while adipocytes are an important metabolic cell type, insulin resistance and T2D are a whole-body affliction, involving many other cell types. To broaden the impact of our work and increase the excitement of the field for the study of insulin signaling and resistance, we expanded our protocol to a panel of 8 other hPSC-derived cell types. We demonstrate physiologically relevant insulin response for each cell type, and we highlight that our insulin-resistance inducing conditions blunt the insulin response in every cell type. Additionally, we validate that key cell identity markers are not lost during this adaptation. By adapting a simple, defined protocol to a wide panel of human in vitro cell types, we can now investigate the cell-autonomous origins of insulin resistance under physiologically relevant conditions.

cell biology↗

bioRxiv2025

Artificial light at night consistently impacts avian physiology and behaviour: a meta-analysis

Artificial light at night (ALAN) is a major anthropogenic pressure across the tree of life, driving population declines in insects and reptiles. Avian responses to ALAN defy simple patterns, varying in direction and magnitude, and the consequences of these responses remain unresolved. We conducted a meta-analysis to test how ALAN alters physiological, behavioural and life history traits underpinning avian performance. We analysed 623 effect sizes from 36 studies in 30 species. We found consistent physiological and behavioural shifts under ALAN, while life-history traits were unaffected. ALAN disrupted molecular and endocrine processes, leading to reduced sleep, higher metabolic rate, and accelerated reproductive maturation. Behaviourally, daily activity was extended, with earlier onset, later offset, and increased nocturnal activity and foraging effort. ALAN effects were stronger in migratory species and more pronounced in adults and females than nestlings and males. Higher light intensities amplified activity shifts, ageing, and sleep disruption, whereas exposure below 2 lux had minimal impact. Birds appear to buffer ALAN effects through physiological and behavioural adjustments, minimising impacts on life-history traits, a paradox likely explained by phenotypic plasticity or evolutionary adaptation. We identified light intensity threshold and group-specific vulnerabilities, emphasizing the need for targeted conservation in our increasingly illuminated world.

ecology↗

bioRxiv2025

Detection dog performance state estimation from pre-stimulus video and physiological signals using deep learning and Bayesian inference

Detection dogs play a critical role in operational settings ranging from explosives detection to medical diagnostics. Their unmatched olfactory capabilities allow them to locate trace-level targets that remain beyond the reach of current technology. However, detection performance can decline without overt behavioral signs, posing a challenge for timely and informed deployment decisions. Identifying subtle precursors to missed alerts remains an open problem with both practical and computational significance. To address this, we recorded detection dogs on a treadmill-based scent delivery system under tightly controlled conditions, enabling precise timing of odor presentation. We focused on the 4.5 seconds preceding each odor pulse to capture anticipatory movement through video and physiological state via sensors. Using markerless pose estimation, we extracted high-resolution joint trajectories, while concurrent recordings provided heart rate, heart rate variability, and core temperature. We trained a spatiotemporal deep learning model that integrates Graph Attention Networks and Temporal Convolutional Networks to predict missed indications from these short, pre-stimulus windows. The model successfully identified 85% of missed alerts with 81% precision. Heart rate variability emerged as the most informative physiological input, suggesting a strong autonomic component to declining readiness. To move from isolated predictions to actionable insights, we implemented a Bayesian aggregation framework that estimates each dogs latent miss rate over time. This probabilistic formulation enables adaptation to individual baselines and operational risk thresholds, supporting context-sensitive deployment decisions. While data were collected in a laboratory setting, our findings highlight behavioral and physiological signatures that precede performance failure. This work lays the foundation for real-time readiness monitoring systems that integrate wearable sensing with interpretable machine learning, supporting timely and welfare-conscious deployment decisions. Author summaryDetection dogs are used in high-stakes situations--from finding explosives to diagnosing diseases. But detection work is physically and mentally demanding, and a dogs performance can quietly decline over time. One challenge is that handlers often cant tell when a dog is starting to lose focus or miss targets until its too late. In our study, we used a treadmill-based setup to record dogs as they performed scent detection tasks. We tracked how they moved, monitored their heart rate and temperature, and trained a computer model to recognize patterns that typically show up just before a missed target. Importantly, we built a second layer that transforms the models output into a running estimate of how likely the dog is to miss a target--based on its recent behavior. This second layer can be tuned to the task and the dog. It can issue earlier warnings during high-risk missions like explosives detection and delay warnings for experienced dogs known to perform reliably even under physical and mental strain. The result is a flexible framework--a first step toward tools that could support better decision-making in real-world deployments.

animal behavior and cognition↗