Biology subjects

Hayes, S.

Publications and source records attributed to Hayes, S..

7 recordsLinked to original sources

bioRxiv2026

Oral somatosensation shapes lingual muscle maps in macaque orofacial primary motor cortex

Oral behaviors such as chewing, swallowing, and speech depend on continuous sensory feedback from the tongue and oral tissues. Yet how oral somatosensation shapes motor cortical output to drive individual tongue muscles remains unknown. We combined electrical stimulation of 96 sites in the orofacial primary motor cortex (M1) with electromyographic (EMG) recordings from six tongue muscles in awake rhesus macaques (Macaca mulatta). Cortical motor maps of evoked muscle activity were evaluated under three oral sensory conditions: intact sensation, combined oral sensory nerve block, and selective preservation of tongue sensation. Orofacial M1 has a broadly distributed, strongly overlapping, and bilateral organization of individual tongue muscle representations. Under altered sensation, spatial reorganization, attenuation, and enhancement of cortical-to-muscle output emerged within a fast timescale. Selectively preserving tongue sensation neither restored the intact pattern, nor reproduced the combined nerve block pattern; instead, it generated a spatially distinct configuration of cortical-to-muscle outputs. Together, these findings demonstrate muscle-level, input-specific, and dynamic sensory shaping in orofacial M1, establishing oral somatosensory input as an active determinant of tongue-muscle output, rather than a peripheral modulator. The rapid reorganization suggests that altered sensation qualitatively reweights existing sensorimotor pathways, rather than merely scaling cortical output up or down, such that its disruption could immediately degrade tongue muscle coordination while enabling adaptation to sensory loss.

neuroscience↗

bioRxiv2025

Salt stress disrupts local auxin and COP1 gradients in Arabidopsis apical hooks

Seedling establishment is highly sensitive to environmental cues, with light serving as a principal regulator. In darkness, seedlings enter skotomorphogenesis, marked by hypocotyl elongation and apical hook formation, which helps seedlings emerge from the soil to reach the light. Here, we show that salinity impairs soil emergence of Arabidopsis thaliana seedlings by inducing a partially photomorphogenic like phenotype in darkness, characterized by reduced apical hook curvature. Within the hook, salt stress diminished differential epidermal cell elongation required to drive hook bending, and reduced both the auxin signalling maximum and PIN3 abundance on the concave side of the hook. Transcriptome analysis revealed that salt and osmotic stresses directly alter organ-specific transcriptional profiles, including the NaCl-mediated repression of B-BOX DOMAIN PROTEIN 28 (BBX28) in hooks and cotyledons. Under control conditions, BBX28 protein accumulated asymmetrically across the hook, but this pattern was lost under salinity. Notably, the ubiquitin ligase CONSTITUTIVE PHOTOMORPHOGENIC1 (COP1) exhibited an opposite gradient to BBX28, which was similarly disrupted by salt stress or by the inhibition of polar auxin transport, presenting auxin as an upstream regulator of COP1 spatial distribution. Together, these findings establish COP1 asymmetry as a novel feature of the apical hook, indicating that spatial regulation--not just absolute levels--shapes COP1 function, and reveal how salinity disrupts hormonal, transcriptional and protein networks to compromise seedling establishment under stress. Significance StatementSeedling establishment is a critical developmental transition that contributes to survival in the local environment. While light is the primary cue driving de-etiolation, how abiotic stress shapes early development in darkness remains unclear. We show that salinity induces a photomorphogenic-like response in dark-grown Arabidopsis thaliana seedlings, disrupting apical hook formation and soil emergence. This response involves disrupted asymmetrical epidermal cell elongation and auxin signalling, repression of B-BOX DOMAIN PROTEIN 28 (BBX28), and loss of a previously unrecognized spatial gradient of the key light regulator COP1 across the apical hook. Our discovery that COP1 is spatially regulated and disrupted by stress, reveals a new dimension of light signalling and developmental control, highlighting how environmental stress constrains seedling establishment.

plant biology↗

bioRxiv2025

Variants in glycine decarboxylase activate mechanisms of mitochondrial energy metabolism in the brain.

Brain energy metabolism is produced from glucose by mitochondrial oxidative phosphorylation. Variants in the mitochondrial enzyme glycine decarboxylase (GLDC) cause a rare neurological disease, non-ketotic hyperglycinemia (NKH), with expected hallmarks of brain glycine elevation and responsiveness to folate deficiency that are equivalent to the severity of Gldc mutations. We remarkably find that brains of young- attenuated mutant mice with a 1.5-fold increase in glycine are reduced > 5-fold in GLDC, show a decline in both the mitochondrial lipoyl-transfer protein GCSH and lipoylation of the pyruvate dehydrogenase (PDH) complex, as well as concomitant rise in signatures of astrocyte mitochondrial {beta}-oxidation of fatty acids and activation of neuronal PDH. Our findings suggest a novel GLDC mechanism of remodeling mitochondrial energy systems throughout the brain, established early in and sustained throughout post-natal NKH disease.

neuroscience↗

bioRxiv2024

Ecology and environment predict spatially stratified risk of highly pathogenic avian influenza in wild birds across Europe

Highly pathogenic avian influenza (HPAI) represents a threat to animal and human health, with the ongoing H5N1 outbreak within the H5 2.3.4.4b clade being the largest on record. However, it remains unclear what factors have contributed to its intercontinental spread. We use Bayesian additive regression trees, a machine learning method designed for probabilistic modelling of complex nonlinear phenomena, to construct species distribution models (SDMs) for HPAI clade 2.3.4.4b presence. We identify factors driving geospatial patterns of infection and project risk distributions across Europe. Our models are time-stratified to capture both seasonal changes in risk and shifts in epidemiology associated with the succession of H5N6/H5N8 by H5N1 within the clade. While previous studies aimed to model HPAI presence from physical geography, we explicitly consider wild bird ecology by including estimates of bird species richness, abundance of specific taxa, and "abundance indices" describing total abundance of birds with high-risk behavioural traits. Our projections of HPAI clade 2.3.4.4b indicate a shift in persistent, year-round risk towards cold, low-lying regions of northwest Europe associated with H5N1. Methodologically, we demonstrate that while most variation in risk can be explained by climate and physical geography, adding host ecology is a valuable refinement to SDMs of HPAI.

ecology↗

bioRxiv2024

Male and female variability in response to chronic stress and morphine in C57BL/6J, DBA/2J, and their BXD progeny

Drug addiction is a multifactorial syndrome in which genetic predispositions and exposure to environmental stressors constitute major risk factors for the early onset, escalation, and relapse of addictive behaviors. While it is well known that stress plays a key role in drug addiction, the genetic factors that make certain individuals particularly sensitive to stress and thereby more vulnerable to becoming addicted are unknown. In an effort to test a complex set of gene x environment interactions--specifically gene x chronic stress--here we leveraged a systems genetics resource: BXD recombinant inbred mice (BXD5, BXD8, BXD14, BXD22, BXD29, and BXD32) and their parental mouse lines, C57BL/6J and DBA/2J. Utilizing the chronic social defeat stress (CSDS) and chronic variable stress (CVS) paradigms, we first showed sexual dimorphism in the behavioral stress response between the mouse strains. Further, we observed an interaction between genetic background and vulnerability to prolonged exposure to non-social stressors. Finally, we found that DBA/2J and C57BL/6J mice pre-exposed to stress displayed differences in morphine sensitivity. Our results support the hypothesis that genetic variation in predisposition to stress responses influences morphine sensitivity and is likely to modulate the development of drug addiction.

neuroscience↗

bioRxiv2023

Warm temperature and mild water stress cooperatively promote root elongation

Warm temperatures have a dramatic effect on plant development. In shoots, stems elongate, and leaves are raised in a developmental programme called thermomorphogenesis. This results in enhanced leaf cooling capacity1. Thermomorphogenesis is tightly intertwined with light signalling pathways. The level of integration is so high that it has been proposed that shoot temperature sensing may have evolved from the co-option of an existing light signalling pathway during the colonisation of land by plants2. Roots also undergo thermomorphogenesis, but the mechanism by which this occurs is less well understood. Main root elongation is enhanced at warm temperatures, and this response is independent of many of the light and temperature signalling components of the shoot3. Roots develop in darkness and so it is a reasonable assumption that root temperature signalling is not through modulation of light signalling. It was recently speculated that due to the close correlation between warm temperature and soil moisture content, root temperature signalling could feasibly be related to water availability signals2. In this study we tested the interaction between temperature and water availability signalling in plant roots. We found that these environmental factors co-operatively enhance main root elongation. This interaction effect was dependent on SUCROSE NON-FERMENTING RELATED KINASE 2.2 (SnRK2.2) and SnRK2.3 and the E3 ubiquitin ligase CONSTITUTIVELY PHOTOMORPHOGENIC 1 (COP1). We found that SnRK2.2 / 2.3 and COP1 have opposite effects on the stability of the transcription factor ELONGATED HYPOCOTYL 5 (HY5) in elongation zone hair cells. The stability of HY5 in these cell types generally corresponded to the degree of root elongation seen in each mutant background. Our study reveals several molecular components of root thermomorphogenesis and highlights the importance of an integrative approach to plant environmental signalling. Our results may have direct implications for agricultural land management, especially as global climates become more unpredictable.

plant biology↗

bioRxiv2018

Soil salinity inhibits plant shade avoidance

Global food production is set to keep increasing despite a predicted decrease in total arable land [1]. To achieve higher production, denser planting will be required on increasingly degraded soils. When grown in dense stands, crops elongate and raise their leaves in an effort to reach sunlight, a process termed shade-avoidance [2]. Shade is perceived by a reduction in the ratio of red (R) to (FR) light and results in the stabilisation of a class of transcription factors known as PHYTOCHROME INTERACTING FACTORs (PIFs) [3,4]. PIFs activate the expression of auxin biosynthesis genes [4,5] and enhance auxin sensitivity [6], which promotes cell wall loosening and drives elongation growth. Despite our molecular understanding of shade-induced growth, little is known about how this developmental programme is integrated with other environmental factors.\n\nHere we demonstrate that low levels of NaCl in soil strongly impair the ability of plants to respond to shade. This block is dependent upon abscisic acid (ABA) signalling and the canonical ABA signalling pathway. Low R:FR light enhances the expression of a positive regulator of the brassinosteroid (BR) signalling pathway, BRASSINOSTEROID SIGNALLING KINASE 5 (BSK5). We found that ABA inhibits BSK5 up-regulation and interferes with GSK3-like kinase inactivation by the BR pathway, thus leading to a suppression of PIF function. By demonstrating a link between the ABA and BR-signalling pathways this study provides an important step forward in our understanding of how environmental cues are integrated into plant development.

plant biology↗