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bioRxiv2020

Mechanotendography: description and evaluation of a new method for investigating the physiological mechanical oscillations of tendons using a piezo-based measurement system

The mechanotendography (MTG) analyzes mechanical oscillations of tendons during muscular actions. It can be assessed as equivalent to mechanomyography just applied for tendons. Since this method is unknown, the aim of this investigation was to evaluate the technical reliability of a piezo-based measurement system used for MTG.The reliability measurements were performed using audio files played by a subwoofer. The thereby generated mechanical pressure waves were recorded by a piezoelectric sensor based measurement system. The piezo sensor was fixed onto the subwoofer’s coverage. An audio of 40 Hz-sine oscillations and, to stay close to human applications, four different formerly in vivo recorded MTG-signals from Achilles and triceps brachii tendon were converted into audio files and were used as test signals. Five trials with each audio were performed. One audio was used for repetition trials on another day. The correlation of the recorded signals were estimated by the Spearman correlation coefficient (MCC), the intraclass-correlation-coefficient (ICC(3,1)), Cronbach’s alpha (CA) and by mean distances (MD) between the signals. They were compared between repetition and random matched signals.The repetition trials show high correlations (MCC: 0.86 ± 0.13, ICC: 0.89 ± 0.12, CA: 0.98 ± 0.03), low MD (0.03 ± 0.03V) and differ significantly from the random matched signals (MCC: 0.15 ± 0.10, ICC: 0.17 ± 0.09, CA: 0.37 ± 0.16, MD: 0.19 ± 0.01V) (p = 0.001 – 0.043).This speaks for an excellent reliability of the piezo-based measurement system in a technical setting. Since research showed that the skin above superficial tendons oscillates adequately, we estimate this tool as valid for the application in musculoskeletal systems. It might provide further insight into the functional behavior of tendons during muscular activity.NOMENCLATURECACronbach’s alphaCVCoefficient of variationECGElectrocardiographyEMGElectromyographyICCIntra class correlation coefficientMMeanMCCMean spearman correlation coefficientMDMean distancesMMGMechanomyographyMTGMechanotendographyMVCMaximal voluntary contractionNINational InstrumentsSDStandard deviationSNRSignal to noise ratioView Full Text

physiology↗
bioRxiv2020

The molecular and metabolic program for adaptation of white adipocytesto cool physiologic temperatures

Although visceral adipocytes located within the bodys central core are maintained at ~37{degrees}C, adipocytes within bone marrow, subcutaneous, and dermal depots are found primarily within the peripheral shell, and generally exist at cooler temperatures. Responses of brown and beige/brite adipocytes to cold stress are well-studied; however, comparatively little is known about mechanisms by white adipocytes adapt to temperatures below 37{degrees}C. Here we report that adaptation of cultured adipocytes to 31{degrees}C, the temperature at which distal marrow adipose tissues and subcutaneous adipose tissues often reside, induces extensive changes in gene expression, increased anabolic and catabolic lipid metabolism, and elevated oxygen consumption with reduced reliance on glucose and preferential use of pyruvate, glutamine and fatty acids as energy sources. Cool temperatures up-regulate stearoyl-CoA desaturase-1 expression and monounsaturated lipid levels in cultured adipocytes and distal bone marrow adipose tissues, and stearoyl-CoA desaturase-1 activity is required for acquisition of maximal oxygen consumption at 31{degrees}C.

physiology↗
bioRxiv2021

An integrated comparative physiology and molecular approach pinpoints mediators of breath-hold capacity in dolphins

Ischemic events, such as ischemic heart disease and ischemic stroke, are the number one cause of death globally. Ischemia prevents blood, carrying essential nutrients and oxygen, from reaching tissues and organ systems, leading to cell and tissue death, and eventual organ failure. While humans are relatively intolerant to these ischemic events, other species, such as marine mammals, have evolved remarkable tolerance to chronic ischemia/reperfusion during diving. Here we capitalized on the unique adaptations of bottlenose dolphins (Tursiops truncatus) as a comparative model of ischemic stress and hypoxia tolerance to identify molecular features associated with breath-holding. Using RNA-Seq we observed time-dependent upregulation of the arachidonate 5-lipoxygenase (ALOX5) gene during breath-holding. Consistent with the RNA-Seq data, we also observed increased ALOX5 enzymatic activity in the serum of dolphins undergoing breath holds. ALOX5 has previously been shown to be activated during hypoxia in rodent models, and its metabolites, leukotrienes, induce vasoconstriction. The upregulation of ALOX5 occurred within the estimated aerobic dive limit of the species, suggesting that ALOX5 enzymatic activity may promote tolerance to ischemic stress through sustained vasoconstriction in dolphins during diving. These observations pinpoint a potential molecular mechanism by which dolphins, and perhaps other marine mammals, have adapted to the prolonged breath-holds associated with diving.

physiology↗
bioRxiv2021

Physiological and ecological consequences of the water optical properties degradation on reef corals

Degradation of water optical properties due to anthropogenic disturbances is a common phenomenon in coastal waters globally. Although this condition is associated with multiple drivers that affect corals health in multiple ways, its effect on light availability and photosynthetic energy acquisition has been largely neglected. Here, we describe how declining the water optical quality in a coastal reef exposed to a turbid plume of water originating from a man-made channel compromise the functionality of the keystone coral species Orbicella faveolata. We found highly variable water optical conditions with significant effects on the light quantity and quality available for corals. Reduction of light penetration into the water column elicits the development of low-light phenotypes close to theoretical limits of photoacclimation despite their occurrence at shallow depths. Predicted photosynthetic energy depletion with increasing depth is associated with patterns of colony mortality and contraction of the habitable space for the population. A numerical model illustrates the potential effect the progressive degradation of water optical properties on the gradual mortality and population decline of O. faveolata. Our findings suggest that preserving the water optical properties seeking to maximize light penetration into the water column may have an extraordinary impact on coral reefs conservation, mostly toward the deeper portions of reefs.

physiology↗
bioRxiv2021

Evaluation of the growth performance, physiological traits, antioxidant indices, and heat shock protein 70 to dietary supplementation of stinging nettle (Urtica dioica) in broilers exposed to chronic heat stress

Heat stress is known as one of the most prevalent environmental stressors in poultry production, which is associated with oxidative stress. Stinging nettle is a medicinal herb with strong antioxidant properties. The present study was conducted to evaluate the effects of dietary stinging nettle at two different levels (2% and 4%) on growth performance and oxidative stress indices of broilers exposed to chronic heat stress. On day 14, a total of 240 broiler chickens were randomly assigned to 6 treatment groups as follows: 1) NC: negative control; 2) HS: heat-stressed broiler; 3) HS-SN2: heat-stressed broiler fed by 2% dietary stinging nettle; 4) HS-SN4: heat-stressed broilers fed by 4% stinging nettle; 5) SN2: no heat-stressed broilers fed by 2% dietary stinging nettle; 6) SN4: no heat-stressed broilers fed by 4% dietary stinging nettle. Diet supplementation with stinging nettle was performed from days 14 to 35 and a chronic heat stress was induced from days 22 to 29. The growth performance and oxidative indices were evaluated on days 14, 21, 29, and 35. Rectal temperature and panting frequency were assessed on days 22, 25, and 29. As a result, weight gain and food intake decreased in the HS compared to the NC, and these parameters increased in the HS-SN2 and HS-SN4 compared to the HS (P<0.05). The HS, HS-SN2, and HS-SN4 groups had a significantly higher rectal temperature and panting frequency. The HS had the higher circulating MDA and HSP70, and lower T-AOC, SOD, and GSH-Px compared to the treatments. The HS-SN4 had a significantly lower MDA and HSP70, and higher T-AOC, GSH-Px, and SOD compared to the HS and HS-SN2. In conclusion, the addition of 4% stinging nettle powder to the broilers diet improved the oxidative status in heat-stressed birds. Furthermore, this herb could be utilized as a feed additive in poultry diet to improve birds health and defense mechanisms under stressful conditions.

physiology↗
bioRxiv2021

Multiscale model of the physiological control of myocardial perfusion to delineate putative metabolic feedback mechanisms

Coronary blood flow is tightly regulated to ensure that myocardial oxygen delivery meets local metabolic demand via the concurrent action of myogenic, neural, and metabolic mechanisms. While several competing hypotheses exist, the specific nature of the local metabolic mechanism(s) remains poorly defined. To gain insights into the viability of putative metabolic feedback mechanisms and into the coordinated action of parallel regulatory mechanisms, we applied a multi-scale modeling framework to analyze experimental data on coronary pressure, flow, and myocardial oxygen delivery in the porcine heart in vivo. The modeling framework integrates a previously established lumped-parameter model of myocardial perfusion used to account for transmural hemodynamic variations and a simple vessel mechanics model used to simulate the vascular tone in each of three myocardial layers. Vascular tone in the resistance vessel mechanics model is governed by input stimuli from the myogenic, metabolic, and autonomic control mechanisms. Seven competing formulations of the metabolic feedback mechanism are implemented in the modeling framework, and associated model simulations are compared to experimental data on coronary pressures and flows under a range of experimental conditions designed to interrogate the governing control mechanisms. Analysis identifies a maximally likely metabolic mechanism among the seven tested models, in which production of a metabolic signaling factor is proportional to MVO2 and delivery proportional to flow. Finally, the identified model is validated based on comparisons of simulations to data on the myocardial perfusion response to conscious exercise that were not used for model identification.

physiology↗
bioRxiv2021

Physiological changes throughout the ear due to age and noise - a longitudinal study

Biological and mechanical systems, whether by their overuse or their aging, will inevitably fail. Hearing provides a poignant example of this with noise-induced and age-related hearing loss. Hearing loss is not unique to humans, however, and is experienced by all animals in the face of wild and eclectic differences in ear morphology and operation. Here we exploited the high throughput and accessible tympanal ear of the desert locust, Schistocerca gregaria (mixed sex) to rigorously quantify changes in the auditory system due to noise exposure (3 kHz pure tone at 126 dB SPL) and age. We analysed tympanal dispalcements, morphology of the auditory Mullers organ and measured activity of the auditory nerve, the transduction current and electrophysiological properties of individual auditory receptors. We found that noise mildly and transiently changes tympanal displacements, decreases both the width of the auditory nerve and the transduction current recorded from individual auditory neurons. Whereas age - but not noise - decreases the number of auditory neurons and increases their resting potential. Multiple other properties of Mullers organ were unaffected by either age or noise including: the number of supporting cells in Mullers organ or the nerve, membrane resistance and capacitance of the auditory neurons. The sound-evoked activity of the auditory nerve decreased as a function of age and this decrease was exacerbated by noise, with the largest difference during the middle of their life span. This middle-aged deafness pattern of hearing loss mirrors that found for humans exposed to noise early in their life. Key point summaryO_LIAge and noise lead to hearing loss. C_LIO_LITympanal displacements have a transient and delayed reduction after noise. C_LIO_LIThe number of auditory neurons decreases with age. The width of the auditory nerve is reduced with noise exposure. C_LIO_LILocusts repeatedly exposed to noise lost their hearing compared to silent controls, but their hearing became similar to old silent control locusts due to age-related hearing loss dominating. C_LIO_LIThe electrophysiological properties of the auditory neurons and the transduction current remained unchanged for aged locusts but repeated noise exposure led to a cumulative decrease in the transduction current. C_LI

physiology↗
bioRxiv2022

Hyperglycemia in type 2 diabetes: physiological and clinical implications of a brain centered model.

Classically type 2 diabetes is believed to be a result of insulin resistance and relative insulin deficiency. However, evidences have been accumulating against the insulin resistance centered models. Absence of fasting hyperglycemia by insulin receptor knockouts or insulin suppression, evidence for hyperinsulinemia preceding insulin resistance, the perplexing hyperinsulinemic normoglycemic state, reduced glucose transport to the brain preceding hyperglycemia, signs of vasculopathy preceding hyperglycemia, absent or poor correlation between fasting glucose and insulin, very strong positive correlation between indices of insulin resistance and {beta} cell function in population data are some of the anomalous findings which glucose homeostasis models have not addressed so far. With increasing evidence for neuronal involvement in glucose regulation, we propose a refined model of glucose regulation that considers brain glucose and insulin levels as the ultimate target of homeostasis and combines central and peripheral mechanisms of regulation. A model considering reduced rate of blood to brain transportation of glucose and insulin as primary pathology explains most of the patterns, with or without insulin resistance. Apart from resolving multiple anomalies the model also accounts for the limited and inconsistent success of glucose normalization in effectively reducing diabetic complications and mortality.

physiology↗
bioRxiv2022

Reactive Oxygen Species-induced Protein Carbonylation Promotes Deterioration of Physiological Activity of Wheat Seeds

During the seed aging process, reactive oxygen species (ROS) can induce the carbonylation of proteins, which changes their functional properties and affects seed vigor. However, the impact and regulatory mechanisms of protein carbonylation on wheat seed vigor are still unclear. In this study, we investigated the changes in wheat seed vigor, carbonyl protein content, ROS content and embryo cell structure during an artificial aging process, and we analyzed the correlation between protein carbonylation and seed vigor. During the artificial wheat-seed aging process, the activity levels of antioxidant enzymes and the contents of non-enzyme antioxidants decreased, leading to the accumulation of ROS and an increase in the carbonyl protein content, which ultimately led to a decrease in seed vigor, and there was a significant negative correlation between seed vigor and carbonyl protein content. Moreover, transmission electron microscopy showed that the contents of protein bodies in the embryo cells decreased remarkably. We postulate that during the wheat seed aging process, an imbalance in ROS production and elimination in embryo cells leads to the carbonylation of proteins, which plays a negative role in wheat seed vigor.

physiology↗
bioRxiv2022

Physiological Responses to Caprine Coccidiosis During a 100-year Rain Event in Oklahoma: An Opportunistic Case Study with a implications for climate change and clinical diagnosis.

The interaction between inclement weather and disease acquisition is a long-recognized relationship. In the case of coccidiosis, a parasitic infestation of the intestines, wet weather is known to promote incidences in livestock. Our opportunistic investigation tracks blood chemistries of goats that were exposed to coccidian in a 100 year rain event in Oklahoma. Our results suggest a potentially patterned response of blood chemistries that may be developed into a clinical tool in the future and provide warnings for producers of the risks associated with growing incidences of excessively wet weather related to climate change.

physiology↗
bioRxiv2022

Trans-generational physiological condition of embryos is conditioned by maternal thermal stress in Octopus maya

Current anthropogenic global warming generates profound metabolic alterations in marine ectotherm invertebrates capable of leading a wide range of these species to extinction. The most worrying and devastating consequence may be that the effect of thermal stress overpasses the individual generations. To evaluate the transgenerational effect of thermal stress on the cephalopod Octopus maya, this study experimentally tests morphology, respiratory metabolism, antioxidant mechanisms, and oxidative stress indicators of the embryos incubated at two temperatures (24 and 30{degrees}C) produced by females acclimated at 24 and 30{degrees}C. The results demonstrate that, regardless of their incubation temperature, embryos from females acclimated at 30{degrees}C are smaller, show more accelerated development, and higher respiratory rates than those from females acclimated at 24{degrees}C. These embryos confirmed a greater oxidative stress degree, as well as an increased amount of soluble carbonylated proteins and catalase activity as the main enzyme during the activation development stage (even the highest in the embryos incubated at 30{degrees}C). Finally, a collapse of the antioxidant defense system was observed, measured as lower both CAT activity and GSH concentrations. Additionally, soluble carbonylated proteins reduced and GST activity increased in embryos incubated at 30{degrees}C from females maintained at high temperatures in a clear deleterious and transgenerational effect of thermal stress on this octopus species.

physiology↗
bioRxiv2022

High-throughput physiological profiling of endosymbiotic dinoflagellates (Symbiodiniaceae) using flow cytometry

Endosymbiotic dinoflagellates (Family Symbiodiniaceae) are the primary producer of energy for many cnidarians, including corals. The intricate coral-dinoflagellate symbiotic relationship is becoming increasingly important under climate change, as its breakdown leads to mass coral bleaching and often mortality. Despite methodological progress, assessing the phenotypic traits of Symbiodiniaceae in-hospite remains a complex task. Bio-optics, biochemistry, or "-omics" techniques are expensive, often inaccessible to investigators, or lack the resolution required to understand single-cell phenotypic states within endosymbiotic dinoflagellate assemblages. To help address this issue, we developed a protocol that collects information on cell autofluorescence, shape, and size to simultaneously generate phenotypic profiles for thousands of Symbiodiniaceae cells, thus revealing phenotypic variance of the Symbiodiniaceae assemblage to the resolution of single cells. As flow cytometry is adopted as a robust and efficient method for cell counting, integration of our protocol into existing workflows allows researchers to acquire a new level of resolution for studies examining the acclimation and adaptation strategies of Symbiodiniaceae assemblages.

physiology↗
bioRxiv2022

Type 2 diabetes susceptibility gene GRK5 regulates physiological pancreatic β-cell proliferation via phosphorylation of HDAC5 in mice

ObjectiveDiabetes onset is accompanied with {beta}-cell deficiency, and thus restoring functional {beta}-cell mass is a promising therapy for those with diabetes. However, the regulatory mechanisms controlling {beta}-cell mass are not fully understood. Previously, we demonstrated that the transcription factor SOX4 is required for {beta}-cell proliferation in the prediabetic state. To elucidate potential mechanisms by which SOX4 regulates {beta}-cell mass, we performed RNA sequencing (RNA-seq) using pancreatic {beta}-cell specific SOX4 knockout mice ({beta}SOX4 KO). The RNA-seq revealed decreased expression of GRK5, a known type 2 diabetes susceptibility gene whose association with diabetes has not been fully elucidated. Therefore, we aimed to clarify the function of GRK5 in pancreatic {beta} cells. MethodsWe generated a novel pancreatic {beta} cell-specific GRK5 knockout mass ({beta}GRK5 KO) and evaluated glucose tolerance and metabolic changes by body weight measurement, oral glucose tolerance test, and insulin tolerance test. The number of pancreatic {beta} cells was quantified by immunohistochemistry. Glucose loading and Ca2+ imaging was performed on isolated islets to evaluate insulin secretory capacity. To elucidate the mechanism of {beta}GRK5 on {beta} cell mass regulation, we performed RNA-seq of isolated islets and identified the signaling pathways that could be regulated by GRK5. Furthermore, in vitro experiments were conducted using human islets and mouse {beta}GRK5 KO islets to clarify the direct effects of GRK5 on these pathways. Results{beta}GRK5 KO islets showed impaired glucose tolerance and insulin secretion, but no change in body weight or insulin resistance, suggesting that the main cause of impaired glucose tolerance is impaired insulin secretion. Isolated islets showed no abnormalities in insulin secretory capacity or changes in calcium influx, but histologically showed a decrease in {beta} cell mass. Consistent with the decreased {beta} cell mass in {beta}GRK5 KO, the cell cycle inhibitor gene Cdkn1a was upregulated in {beta}GRK5 KO islets; this phenocopies the {beta}SOX4 KO. Furthermore, we found that Grk5 positively regulates facultative increases in {beta} cell mass through activity-dependent phosphorylation of HDAC5 and subsequent transcription of immediate early genes (IEGs) such as Nr4a1, Fosb, Junb, Arc, Egr1 and Srf. ConclusionsOur results suggest that GRK5 is associated with type 2 diabetes through regulation of {beta} cell mass. GRK5 could become a potential target of cell therapy to preserve functional {beta} cells during the progression towards frank diabetes.

physiology↗
bioRxiv2023

Physiological stress response of koala joeys to visitors

Koala (Phascolarctos cinereus) joey rescues are increasing over the years, and rehabilitation of a joey requires extensive care, close proximity and handling by humans. These novel environments are likely to present a suite of biotic and abiotic stressors during rehabilitation. In this study, we longitudinally monitored the faecal cortisol metabolites (FCMs) of three koala joeys within the context of potential stressors at the Magnetic Island Koala Hospital, Queensland, Australia. A total of 92 faecal samples were analysed for FCMs using a polyclonal R4866 cortisol enzyme-immunoassay which has been previously validated in koalas. The iterative baseline method was used to establish FCM profiles of all individuals, and to identify significant peaks in FCM concentrations. Visitor events were identified and confirmed as an acute stressor based on the FCM profiles of the koala joeys. All three koala joeys elicited a significant rise in FCM concentrations after each visitor encounter. To our knowledge, this is the first study to report on the acute stress response of koala joeys to visitors. We recommend that visitor encounters be kept to a minimum, and perhaps avoided altogether especially for joeys that are being rehabilitated to be released back into the wild.

physiology↗
bioRxiv2023

Physiology of the Weight Loss Plateau after Calorie Restriction, GLP-1 Receptor Agonism, and Bariatric Surgery

ObjectiveTo investigate why different weight loss interventions result in varying durations of weight loss prior to approaching plateaus. MethodsA validated mathematical model of energy balance and body composition dynamics was used to simulate mean weight loss trajectories in response to intensive calorie restriction, semaglutide 2.4 mg, tirzepatide 10 mg, and Roux en-Y gastric bypass (RYGB) surgery interventions. Each intervention was simulated by varying two model parameters affecting energy intake to fit the observed mean weight loss data. One parameter represented the persistent magnitude of the intervention to shift the system from baseline equilibrium and the other parameter represented the strength of the feedback control circuit relating weight loss to increased appetite. ResultsRYGB surgery resulted in a persistent intervention magnitude more than 4-fold greater than calorie restriction and about double that of tirzepatide and semaglutide. All interventions except calorie restriction substantially weakened the appetite feedback control circuit resulting in an extended period of weight loss prior to the plateau. ConclusionsThese preliminary mathematical modeling results suggest that both GLP-1 receptor agonism and RYGB surgery interventions act to weaken the appetite feedback control circuit regulating body weight and induce greater persistent effects to shift the body weight equilibrium as compared to intensive calorie restriction.

physiology↗
bioRxiv2024

Muscle-fiber specific genetic manipulation of Drosophila sallimus severely impacts neuromuscular development, morphology, and physiology

The ability of skeletal muscles to contract is derived from the unique genes and proteins expressed within muscles, most notably myofilaments and elastic proteins. Here we investigated the role of the sallimus (sls) gene, which encodes a structural homologue of titin, in regulating development, structure, and function of Drosophila melanogaster. Ubiquitous knockdown of sls using RNA interference (RNAi) in all muscle fibers resulted in embryonic lethality. A screen for muscle-specific drivers revealed a Gal4 line that expresses in a single larval body wall muscle in each abdominal hemisegment. Disrupting sls expression in single muscle fibers did not impact egg or larval viability nor gross larval morphology, but did significantly alter the morphology of individual muscle fibers. Analysis of individual sarcomeres revealed significant changes in ultrastructural organization, dramatically increasing sarcomere, I-band, A-band, and sls-band lengths. Surprisingly, muscle-cell specific disruption of sls also severely impacted neuromuscular junction (NMJ) formation. The extent of motor-neuron (MN) innervation along disrupted muscles was significantly reduced along with the number of glutamatergic boutons, in MN-Is and MN-Ib. Electrophysiological recordings revealed a 40% reduction in excitatory junctional potentials correlating with the extent of motor neuron loss. Analysis of active zone (AZ) composition revealed changes in presynaptic scaffolding protein (brp) abundance, but no changes in postsynaptic glutamate receptors. Ultrastructural changes in muscle and NMJ development at these single muscle fibers were sufficient to lead to observable changes in neuromuscular transduction and ultimately, locomotory behavior.

physiology↗
bioRxiv2024

Portal bile acids and microbiota along the murine intestinal tract exhibit sex differences in physiology

Microbes in the intestine transform bile acids during transit, altering their functional and signaling capacities before absorption into the portal vein. Sex differences in the gut microbiota have been noted, but their consequence on bile acid composition is unclear. Here, we investigated the composition and imputed functional potential of microbes in the small and large intestine together with portal and systemic bile acids. Female and male mice exhibit distinct microbial diversity throughout the length of the intestine leading to dimorphism in genes related to bile acid transformation. Subsequently, we found that the total portal bile acid concentrations were doubled in female mice compared to males. Conversely, oxo-bile acids that are rare in systemic circulation represented almost 30 percent of the portal pool in the male mice. Oxo- and deconjugated-bile acids were absent in germ-free mice consistent with microbe-mediated bile acid transformation. More importantly, gnotobiotic mice do not show sex differences in portal bile acids. Taken together, we demonstrate that sex differences in gut microbiota cause dimorphism in bile acid levels within the enterohepatic loop. HighlightsO_LIMurine microbial diversity exhibits sex-specific patterns along the small intestinal tract and colon. C_LIO_LIDistinct gut microbial profiles confer differential abundance of secondary bile acid metabolism genes in male and female mice. C_LIO_LIPortal bile acid compositions mirror sex differences in microbe-mediated bile acid processing that are lost in germ free conditions. C_LI

physiology↗
bioRxiv2024

Alleviation of salt stress in strawberries by hydrogen-rich water: physiological, transcriptomic and metabolomic responses

O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=108 SRC="FIGDIR/small/605184v1_ufig1.gif" ALT="Figure 1"> View larger version (21K): org.highwire.dtl.DTLVardef@1aa6488org.highwire.dtl.DTLVardef@1ae580borg.highwire.dtl.DTLVardef@11656bcorg.highwire.dtl.DTLVardef@1985c7b_HPS_FORMAT_FIGEXP M_FIG C_FIG With the continuous advancement of climate change and human activities, cultivable land is becoming increasingly susceptible to the influence of salt ions. Therefore, it is crucial to mitigate the salt stress on plants through various approaches. In this study, strawberry seedlings were selected as the experimental plants, and a comprehensive transcriptomic and metabolomic analysis was conducted to elucidate the effects of hydrogen-rich water (HRW) on strawberries under salt stress. The results indicated that HRW significantly promoted plant growth, particularly increasing root biomass by 49.50%. Additionally, HRW regulated the levels of soluble sugars, malondialdehyde (MDA), and antioxidant enzymes, enhancing the cellular uptake of potassium ions and the expulsion of sodium ions. The levels of Ca2+ and Mg2+ in organelles increased by 2.06 and 2.45-fold, respectively. Transcriptomic analysis revealed that HRW substantially altered gene expression in strawberry roots; under salt stress, HRW up-regulated beneficial biological processes. Furthermore, genes related to ion absorption and transport, antioxidant enzymes, and cell wall biosynthesis were screened. Meanwhile, key common pathways were identified in differentially expressed metabolites (DEMs) and differentially expressed genes (DEGs) related to phenylpropane biosynthesis, alanine, aspartate, and glutamate metabolism, amino and nucleotide sugar metabolism, and galactose metabolism. A molecular mechanism for mitigating salt stress in strawberry seedlings by HRW was provided by the integrated approaches in this research, reflecting the potential applications of hydrogen gas in agriculture.

physiology↗