Energy Expenditure Research Articles

Melanocortin 4 receptor mutation in obesity

Obesity is increasingly prevalent worldwide, with genetic factors contributing to its development. The hypothalamic leptin-melanocortin pathway is central to the regulation of appetite and weight; leptin activates the proopiomelanocortin neurons, leading to the production of melanocortin peptides; these in turn act on melanocortin 4 receptors (MC4R) which suppress appetite and increase energy expenditure. MC4R mutations are responsible for syndromic and non-syndromic obesity. These mutations are classified based on their impact on the receptor's life cycle: i.e. null mutations, intracellular retention, binding defects, signaling defects, and variants of unknown function. Clinical manifestations of MC4R mutations include early-onset obesity, hyperphagia, and metabolic abnormalities such as hyperinsulinemia and dyslipidemia. Management strategies for obesity due to MC4R mutations have evolved with the development of targeted therapies such as Setmelanotide, an MC4R agonist which can reduce weight and manage symptoms without adverse cardiovascular effects. Future research directions must include expansion of population studies to better understand the epidemiology of MC4R mutations, exploration of the molecular mechanisms underlying MC4R signaling, and development of new therapeutic agents. Understanding the interaction between MC4R and other genetic and environmental factors will be key to advancing both the prevention and treatment of obesity.

A framework for validating efficiency models of thermal separation columns with tray internals

Abstract Tray columns are globally used for distillation processes, and their performance must be optimized to reduce their cost and energy expenditures as well as carbon emissions. A prerequisite to achieve these targets demands a realistic account of the tray performance based on tray efficiency model application. The proof of concept of a Refined Residence Time Distribution (RRTD) model, recently proposed by the authors, is presented. The multifaceted challenges in acquiring hydrodynamic and performance data suitable for model validation are discussed in this work. In that regard, an unprecedented experimental campaign was performed in a representative large-scale air-water tray column simulator based on the application of multiplex flow profiler, new chemical system, and novel data processing schemes. Using these data and additional case studies, the capabilities of the RRTD model were demonstrated. This model successfully accounted for the impacts of varying local liquid flow characteristics and vapor flow maldistributions on the tray efficiency thereby advancing the state of the art of the tray efficiency models. This work particularly aimed at proposing a constructive framework to evaluate tray efficiency models in the future campaigns, and those campaigns will benefit from the learnings of the present work.

An acute bout of 4 x 4-minute or 10 x 1-minute HIIT improves beta cell glucose sensitivity in post-menopausal females with type 2 diabetes: a secondary analysis.

Aims/hypothesis: Improvements in glycemic control following acute exercise are typically attributed to improved post-exercise insulin sensitivity (IS) with comparatively little known about how acute exercise impacts beta cell function, especially in post-menopausal females. We determined how two high-intensity interval training (HIIT) protocols, matched for total estimated energy expenditure, impact beta cell function in post-menopausal females with type 2 diabetes. Methods: Thirteen post-menopausal females (70 ± 5 years; 12 ± 7 years since diagnosis, 80.9 ± 13.8 kg, 32.4 ± 5.6 kg*m2; HbA1c - 49.8 ± 10.3 mmol/mol [6.7 ± 1.0]) living with type 2 diabetes were included in this semi-randomized crossover trial. The trial involved an initial resting control condition followed by two HIIT conditions [4 X 4-minute HIIT (HIIT4) and 10 X 1-minute HIIT (HIIT10)] completed in a randomized order 2-4 days apart. Beta cell function (glucose sensitivity) and insulin sensitivity were determined from a 2 h mixed-meal tolerance test performed 2 hours after rest or HIIT. Results: Both HIIT4 and HIIT 10 significantly improved beta cell glucose sensitivity compared to control (15 pmol*min-1*m-2[mmol/L]-1, [95% CI 6, 23]; p= 0.002 and 16 pmol*min-1*m-2[mmol/L]-1, [95% CI 7, 25]; p= 0.002, respectively), with no difference between HIIT protocols (1 [-8, 10], P = 0.79). There were no significant differences in IS metrics (Matsuda index, OGIS, Stumvoli, and QUICKI) between the conditions. Conclusions/interpretation: An acute bout of 4 X 4-minute or 10 X 1-minute HIIT improves beta cell glucose sensitivity in post-menopausal females living with type 2 diabetes.

The relationship between serum CTRP-5, C3a/desArg, and complement-C3 levels and hypothyroidism in women with polycystic ovary syndrome

IntroductionMany patients with polycystic ovary syndrome (PCOS) also experience thyroid disorders. There is a notable similarity in energy metabolism among PCOS, C1q/tumor necrosis factor (TNF)-related proteins (CTRP-5)deficiency, C3a/desArg (also known as acylation-stimulating protein (ASP)) deficiency, and hypothyroidism. This study aimed to investigate the relationship between serum levels of these factors and hypothyroidism in patients with PCOS. Improved clarity and vocabulary, corrected minor grammatical issues, and enhanced readability.MethodsThis case-control study involved three groups: healthy women (control group), women with PCOS and hypothyroidism, and women with PCOS without hypothyroidism. Serum levels of FBS, total cholesterol, triglycerides, and HDL-C were measured using enzymatic and colorimetric methods. TSH, T4, T3, and anti-thyroid peroxidase (Anti-TPO) levels were determined by ELISA to screen for hypothyroidism in women with PCOS. Additionally, serum levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH), CTRP-5, ASP, and complement C3 were assessed using the ELISA method.ResultsThe results indicated that reduced blood levels of CTRP-5, along with elevated levels of ASP (C3a/desArg) and complement C3 in patients with PCOS, may be linked to dysregulation of the thyroid gland. Furthermore, the study observed that changes in these parameters, in conjunction with thyroid dysfunction, are associated with pathological alterations in lipid profiles and blood glucose levels.ConclusionWhile changes in CTRP-5, ASP, and complement C3 can influence energy expenditure and storage in PCOS and thyroid function, the complex nature of PCOS requires further research to investigate the prevalence of hypothyroidism in individuals with PCOS.Clinical trial numberNot applicable

Accuracy of the Apple Watch Series 9 for Measures of Energy Expenditure and Heart Rate at Rest and During Exercise: Impact of Skin Pigmentation

Background: The Apple Watch provides promising health data that could aid in increasing exercise adherence; regular exercise can help individuals manage and prevent diseases such as obesity and cardiovascular disease. However, the impact of skin pigmentation on the accuracy of the Apple Watch Series 9 for measures of energy expenditure (EE) and heart rate (HR) is unknown. Purpose: The purpose of this study was to determine the accuracy of the Apple Watch Series 9 on various skin pigmentations for measures of EE and HR. Methods: Thirty young, healthy individuals were assigned to one of three groups based on their scores on the Fitzpatrick skin survey. Participants completed a 10 min treadmill protocol with varying speeds and inclines while wearing an Apple Watch Series 9, a two-way non-rebreathing mouthpiece connected to a Parvo Medics metabolic cart, and a Polar H7 chest strap to measure EE and HR. Results: Overall, EE was found to be inconsistent for all skin pigmentation groups. However, for HR, the Apple Watch Series 9 was more variable (i.e., less accurate) for darker skin pigmentations compared to lighter skin pigmentations. Conclusions: The Apple Watch Series 9 was found to vary in both EE and HR measures from criterion across intensity and skin pigmentation, with greater discrepancies for individuals in Group 3 for measures of HR. Further investigation might aim to study the impact of skin pigmentations and wrist subcutaneous fat on the accuracy of the latest Apple Watch Series 9 for measures of EE and HR.

Sanctuary for migrating and wintering waterfowl: Synthesis and insights for waterfowl management and conservation planning

AbstractWaterfowl use a diversity of resources (e.g., food, structure, sanctuary) to meet energetic, social, and other life‐history demands during the non‐breeding period. Waterfowl often seek areas with limited human disturbance (i.e., sanctuary) during autumn and winter when hunting seasons are open perhaps to reduce exposure to mortality risks, minimize energy expenditure, and increase foraging efficiency, all of which should enhance survival and subsequent fitness. Prior studies of sanctuary use by waterfowl have mostly focused on patterns of abundance and behavior, with many documenting differential diel movements of marked birds in and around sanctuaries. Although reduced mortality risk is likely associated with sanctuary use, much less is known about the potential effects on energy expenditure, body condition, reproductive consequences at the individual level, and seasonal distribution with respect to viewing and harvest potential. We consider these aforementioned factors among the most significant gaps in our understanding of the function of sanctuary in waterfowl management. As waterfowl hunter recruitment, retention, and reactivation have become a major initiative of many natural resource agencies and a core principle of the North American Waterfowl Management Plan, we discuss the potential role of sanctuary relative to these efforts. Herein, we review historical aspects of waterfowl sanctuary, introduce hypotheses about its potential role in habitat resource management and conservation planning during autumn and winter, discuss our knowledge of the effects of sanctuary on waterfowl, and share insights to inform decisions about the role of sanctuary in waterfowl management given currently available evidence and remaining uncertainties. Our review describes the existing evidence for the biological and social outcomes of sanctuary, draws some conclusions about the role of sanctuary in natural resource management given the available evidence, and outlines potential research opportunities to help us make informed decisions regarding sanctuary implementation for waterfowl.

Shear stress-stimulated AMPK couples endothelial cell mechanics, metabolism and vasodilation.

Endothelial cells respond to mechanical force by stimulating cellular signaling, but how these pathways are linked to elevations in cell metabolism and whether metabolism supports the mechanical response remains poorly understood. Here, we show that the application of force to endothelial cells stimulates VE-cadherin to activate liver kinase B1 (LKB1; also known as STK11) and AMP-activated protein kinase (AMPK), a master regulator of energy homeostasis. VE-cadherin-stimulated AMPK increases eNOS (also known as NOS3) activity and localization to the plasma membrane, reinforcement of the actin cytoskeleton and cadherin adhesion complex, and glucose uptake. We present evidence for the increase in metabolism being necessary to fortify the adhesion complex, actin cytoskeleton and cellular alignment. Together, these data extend the paradigm for how mechanotransduction and metabolism are linked to include a connection to vasodilation, thereby providing new insight into how diseases involving contractile, metabolic and vasodilatory disturbances arise.

Orexin in depression: Evidence from basic and clinical research

Orexin – a neuropeptide – is extensively distributed in the central nervous system and is involved in the regulation of diverse physiological functions and behaviors. Orexin is strongly associated with the onset and development of depression. The most important function of orexin is to interact with the transport system, mediating arousal, and energy homeostasis. Hypothalamic-ventral tegmental and hypothalamic-ventral thalamic pathways provide clues for understanding the function of orexin and related disorders, such as sleep disorders, eating disorders, and substance abuse. This article summarizes the basic and clinical studies on the role of the orexin system in regulating and treating depression, including the relationship between the expression level of orexin in specific brain areas and diseases, relationship between adolescent depression and orexin, orexin receptor antagonists as a treatment for depression, and narcolepsy, which is closely associated with depression. Research progress on the role of orexin in depression and recent relevant studies are summarized, providing novel directions for developing depression treatment strategies.

Resting energy expenditure: Is there any difference between dialysis and non-dialysis dependent chronic kidney disease patients?

Resting energy expenditure: Is there any difference between dialysis and non-dialysis dependent chronic kidney disease patients?

Nanozyme as Tumor Energy Homeostasis Disruptor to Augment Cascade Catalytic Therapy.

Breaking the balance of the tumor microenvironment and reshaping it sustainably remain major challenges in lung cancer treatment. Here, a "tumor energy homeostasis disruptor", the Cu2O@Au nanozyme was developed, which exhibits excellent glucose oxidase-like activity, enabling it to be used for starvation therapy and as a mimic peroxidase for chemodynamic therapy (CDT), producing •OH. Cu2O@Au nanozymes consume glucose at the tumor site to block the tumor's energy supply, produce H2O2 continuously, and lower the pH to enhance the efficiency of CDT, initiating a cascade reaction that leads to a storm of reactive oxygen species (ROS). Furthermore, Cu2O@Au nanozyme consumes glutathione and reduces the expression of the SLC7A11 (xCT) protein to decrease cancer cell uptake of cysteine, further enhancing the burst of ROS, resulting in lipid peroxidation in tumor cells and ultimately leading to ferroptosis. The excellent photothermal performance of Cu2O@Au can further enhance CDT. Additionally, Cu2O@Au nanozyme also has computed tomography (CT) and photothermal imaging capabilities. In conclusion, Cu2O@Au nanozymes, acting as tumor energy homeostasis disruptor, can effectively inhibit tumor growth and successfully achieve the synergistic effects of starvation therapy/CDT/photothermal therapy (PTT). This multifunctional nanozyme holds promise for providing valuable insights and therapeutic strategies for cancer treatment.

High-Intensity Intervallic Exercise (HIIE) Is Superior to Isocaloric Moderate-Intensity Continuous Exercise (MICE) at Reducing Postprandial Hyperglycemia.

We investigated if a bout of HIIE is more efficacious at reducing postprandial hyperglycemia than an isocaloric bout of MICE. Nineteen healthy physically active individuals (21% women) completed three trials in a randomized order: i) HIIE cycling consisting of 5 bouts of 4 min at 83 ± 9% of subjects' maximal oxygen consumption (V˙O2 MAX) with active recoveries at 53 ± 8% for a total of 50 min; ii) MICE cycling at 65 ± 8% of V˙O2 MAX for 50 min, and iii) CONTROL no exercise. All trials were followed by a standard oral glucose tolerance test (OGTT) ingesting 74 grams of glucose traced with 1 gram of uniformly labeled [13C]-glucose. Plasma glucose and insulin concentrations, and plasma glucose kinetics ([6,6 2H2] glucose infusion) were measured before, during exercise, and during the OGTT. Insulin sensitivity was estimated by the Matsuda index (ISI). Energy expenditure and carbohydrate oxidation (CHOxid) were monitored. At rest, blood glucose, insulin concentrations, and CHOxid were similar in all three trials. During exercise, energy expenditure was similar in HIIE vs MICE (548 ± 131 vs 560 ± 125 kcals; p = 0.340). However, CHOxid, plasma glucose concentration, and its rates of appearance in plasma (Ra) were higher in HIIE vs MICE (Ra glucose 34.3 ± 9.8 vs 28.9 ± 6.8 μmol·kg-1·min-1; p = 0.021). During the OGTT, plasma glucose and insulin concentrations were lower, and insulin sensitivity higher in HIIE vs CONTROL (ISI MATSUDA; 12.4 ± 4.7 vs 10.8 ± 4.7 au; p = 0.007). Exercise delayed blood incorporation of [13C]-glucose into blood (p = 0.023). Early during the OGTT, glucose clearance rates were higher in HIIE vs CONTROL (7.1 ± 3.1 vs 5.5 ± 3.0 mL·kg-1·min-1; p = 0.015). HIIE is more effective than MICE to reduce hyperglycemia and hyperinsulinemia after glucose ingestion. HIIE improves glycemic control by increasing splanchnic glucose retention and glucose clearance rates.

Диагностическая эффективность и прогностическая значимость антропометрических параметров как маркеров гиперлептинемии у подростков

Leptin is an energy homeostasis marker synthesized by cells of adipose tissue (adipocytes) and gastric mucosa. The search for clinical and anthropometric parameters associated with energy homeostasis disorders in excess body weight (BW) and obesity is necessary for stratification of patients at risk for early implementation of energy homeostasis disorders. The purpose of this re-search was to evaluate the relationship between serum leptin concentration and anthropometric parameters reflecting the topography of subcutaneous fat in adolescents of different ethnicities with excess BW and obesity in order to identify the most informative anthropometric parameters of energy homeosta-sis disorders. Materials and methods used: a single-center cross-sectional study of 362 adolescents aged 11 to 17 y/o residing in the Republic of Buryatia and the Irkutsk Oblast of Russia was conducted in 2015-2016 that included the participants as follows: 186 Caucasians (46 boys/140 girls) and 176 Mongoloids (96 boys/80 girls); 136 adolescents in the control group (38%) and 226 adolescents with excess BW and obesity (62%). All par-ticipants had their linear height, BW, waist (WC) and hip (HC) circumference, skinfold thickness measured as well as the body mass index (BMI, in kg per m2) calculated. The concentrations of glucose, total cholesterol, high-density, low-density and very low-density lipoprotein cholesterol, triglycerides and in-sulin were determined. The HOMA index was calculated. Serum leptin was de-termined by enzyme immunoassay using DBC Leptin ELISA kit (Diagnostics Biochem Canada Inc., Canada) with detection using BioTek Elx808 Microplate Spectrophotometer (Agilent Technologies, Inc., USA). Results: a strong posi-tive correlation was found between serum leptin levels and SDS BMI and trip-onderal BMI in adolescents of both ethnic groups: in Caucasian boys r=0.747 (p<0.001), r=0.767 (p<0.001), in Caucasian girls r=0.687 (p<0.001) and r=0.695 (p<0.001); in Mongoloid boys r=0.765 (p<0.001), r=0.852 (p<0.001), in Mongoloid girls r=0.612 (p<0.001), r=0.667 (p<0.001), respectively. Ac-cording to the results of ROC analysis, AUC WC/height showed good diagnos-tic significance for detecting hyperleptinemia (AUC=0.8-0.9) in adolescents from all the studied groups. Conclusion: the triponderal index and the WC/height ratio are informative anthropometric indicators for energy metabo-lism disorders and hyperleptinemia in Caucasian and Mongoloid adolescents of both genders with excess BW and obesity.

Mitochondrial fission is required for thermogenesis in brown adipose tissue.

Brown adipose tissue (BAT) thermogenesis is pivotal for maintaining body temperature and energy balance. Mitochondrial morphology is dynamically controlled by a balance between fusion and fission, which is crucial for cell differentiation, response to metabolic insults, and heat production. Dynamin-related protein 1 (Drp1) is a key regulator of mitochondrial fission. This study investigates the role of Drp1 in BAT development and thermogenesis by generating Drp1-deficient mice. These mice were created by crossing Drp1 floxed mice with fatty acid-binding protein 4-Cre (aP2-Cre) transgenic mice, resulting in aP2-Cre+/-Drp1flox/flox (aP2-Drp1f/f) mice. The aP2-Drp1f/f mice exhibited severe BAT and brain hypoplasia, with the majority dying within 48 hours postnatally, highlighting Drp1's crucial role in neonatal survival. Impaired thermogenic responses were observed in aP2-Drp1f/f mice, characterized by significantly decreased expression of thermogenic and lipogenic genes in BAT. Ultrastructural analysis revealed disrupted mitochondrial morphology and reduced lipid droplet content in BAT. The few surviving adult aP2-Drp1f/f mice also showed impaired BAT and brain development, along with BAT thermogenesis dysfunction during cold exposure. Our findings underscore the essential role of Drp1-mediated mitochondrial fission in BAT thermogenesis and neonatal survival, providing insights into potential therapeutic approaches for metabolic disorders.

Indian perspective on childhood malnutrition: Prevalence, pathophysiology, risk factors, and prevention.

Childhood malnutrition contributes over half of the childhood mortality around the world, predominantly in South-Asian and sub-Saharan countries. To summarize the childhood malnutrition epidemiology along with the comorbid factors associated with it and its management within the community. The data collection process involved conducting a comprehensive search using specific keywords such as child nutrition disorders and India with Boolean operators. The search was conducted in the Scopus and PubMed electronic databases. Inadequate energy consumption initiates pathological alterations in the form of growth retardation, fat, visceral, and muscle loss, a reduction in basal metabolic rate, and a significant reduction in total energy expenditure. It has become evident that malnutrition shows an increased prevalence and incidence rate, despite available guidelines for the management of malnutrition. Malnutrition can be a major player in the establishment of severe infections that result in significant post discharge mortalities in children. Future trials are required to fill the prime gaps in knowledge regarding the identification of other contributory factors in the pathogenesis of malnutrition and post-discharge infection. New biomarkers for early detection of malnutrition should be the priority of the scientific community for the early management of malnutrition.

Physiological response in professional female soccer players

The aim of this study was to describe the physiological characteristics and energetic requirements of small-side games (SSG) in female players by means of ambulatory gas exchange measurements using a breath-by-breath (B × B) approach. Eight female professional soccer players participated in this study. This study was divided into two sessions: laboratory exercise testing and SSG field testing. Both tests were performed using simultaneous gas exchange measurements. The incremental ramp exercise test was performed using portable metabolic carts breath by breath (B×B) and a treadmill, to measure the maximum oxygen uptake (VO2max) and maximum heart rate (HRmax) of each player. In the SSG field test, the metabolic carts (B×B), was used during SSG to measure oxygen uptake (VO2), average heart rate (HRave), breath frequency (fB), minute ventilation (VE), energy expenditure (EE), and heart Rate and O2 Pulse (VO2/HR). Activity profiles were assessed by professional technical coaches (n = 2). A total of 152 passes were included in the four-a-side SSG analysis. Specifically, 85.53% of the total passes were categorized as successful passes and 14.47% were categorized as failed passes. VO2 during SSG was 83.90% of the VO2max, and HRave during SSG was 84.42% of the HRmax. The independent t-test showed a difference between blood lactate levels post-SSG and blood lactate after the incremental ramp-like exercise [p = .001; F = 97.294]. Four-a-side SSG have sufficient physiological demands for female players, characterized by achieving the minimum standard of physiological response with maximum aerobic capacity.

The Influence of Stress and Inactivity on Health: An Ayurvedic Perspective

Sedentary behavior, defined as activity that involves little to no movement of the body and, consequently, low energy expenditure, has recently gained attention as a potential indicator of the physical and mental health of adult populations. Sedentary behavior has been linked to mental health problems like anxiety, depression, and low self-esteem. These days, life is extremely busy - almost chaotic. Despite our increased productivity, we still feel there is never enough time to accomplish our true goals. This extremely rapid pace and the pressure that follows to "get things done" are serious issues that have a deeper impact on our bodies and minds than we may realize. We are all making ourselves sick by stressing about something that is not even a small inconvenience. The body contains thousands of homeostatic regulatory mechanisms. Among the most crucial ones are the control of body temperature, the maintenance of cell nutrition, the removal of waste, and the proper balance of hormones. So, the term "stress" is fairly wide and can take many various forms, it can interfere with several vital physiological processes.

Gut-brain axis: The role of gut microbiota in energy balance and body weight regulation

Obesity currently represents a major societal and health problem worldwide. Its prevalence has reached epidemic levels, and trends continue to increase; This, in turn, reflects the need for more effective preventive measures. Dietary composition is one of the main factors that modulate the structure and function of the gut microbiota. Therefore, abnormal dietary patterns or unhealthy diets can alter gut microbiota-diet interactions and alter nutrient availability and/or microbial ligands that transmit information from the gut to the brain in response to nutrient intake, thereby disrupting energy homeostasis. Accordingly, this review aims to examine how dietary composition modulates the gut microbiota and thus the potential effects of these biological products on energy homeostasis through gut-brain based mechanisms. It also assesses the knowledge gaps and advances needed to clinically implement microbiome-based strategies to improve gut-brain axis function and therefore combat obesity.

Enhancing Fish Passage Efficiency: Lessons from UHE Porto Primavera’s Fish Ladder

Dams severely affect aquatic environments and block the longitudinal migration of fish. In order to mitigate the negative effects generated by these developments, fish passes, or fishways, are implemented in dams with the purpose of restoring river connectivity and allowing the movement of migrants. Nevertheless, fishways in neotropical areas often face design and construction issues that can reduce their efficiency and selectively disadvantage species with limited swimming capabilities. This study analyzes how a fish ladder on the Paraná River influences the black armored catfish (Rhinelepis aspera), a benthic, long-distance migratory species important to commercial fisheries. A total of 200 individuals were PIT-tagged and monitored for four months. The results showed that although many fish successfully located the fishway, only a small portion (3.5%) managed to complete the ascent. The interaction between the hydraulic characteristics of the fishway and the fish condition factor played a significant role in ascent performance. Our findings underscore the importance of assessing fishway suitability for benthic neotropical species to support conservation efforts in the Upper Paraná River Basin. To improve passage rates for R. aspera, we recommend optimizing flow conditions by adjusting orifice and notch configurations, incorporating roughness elements, and modifying resting pool designs. These adaptations would reduce energy expenditure for ascending fish, enhancing fishway performance and contributing to the sustainability of migratory species in this region.

Multi-omics analysis and longitudinal study of reprogramming by dietary creatine to endogenous metabolism in largemouth bass (Micropterus salmoides).

Creatine is a feed additive with physiological pleiotropic properties and also an energy homeostasis protector in vertebrates and is successfully used in terrestrial livestock and aquaculture. Here, two feeding trials were performed to investigate dietary creatine on endogenous creatine metabolism and physiological reprogramming in largemouth bass. The results showed that the endogenous creatine metabolism genes AGAT, GAMT, and SLC6A8 of largemouth bass are highly conserved with the amino acid sequences of other teleosts and are clustered separately from mammals. Among the 16 major tissues in largemouth bass, both creatine synthesis genes (agat, gamt) and transporter gene slc6a8 are most highly expressed in muscle. Muscle has a high threshold but sensitive creatine negative feedback to regulate endogenous creatine metabolism. Dietary creatine intake significantly inhibits endogenous creatine synthesis and transport in muscle in a dose-dependent manner, and this inhibitory effect recovers with a decrease in dietary creatine content. In addition, physiological creatine saturation required prolonged exogenous creatine intake, and it would be shortened by high doses of creatine, which provides guidance for maximizing economic benefits in aquaculture. Metabolome and transcriptome showed that dietary creatine significantly affected the metabolism of the creatine precursor substance-arginine. Exogenous creatine intake spared arginine that would otherwise be used for creatine synthesis, increased arginine levels, and caused reprogramming of arginine metabolism. Overall, these results demonstrate that the addition of creatine to largemouth bass diets is safe and recoverable, and the benefits of creatine intake in largemouth bass are not limited to enhancing the function of creatine itself but also include a reduction in the metabolic burden of essential amino acids to better growth performance.

Effect of the Nucleosome-Depleted Region in the Transcribed Regions of Saccharomyces cerevisiae Genes on Exogenous Gene Expression

Nucleosome sequence composition is closely associated with gene expression. The nucleosome-depleted region (NDR) within the transcriptional regulatory region of S. cerevisiae genes plays a crucial role in the regulation of gene expression. To investigate the effect of NDR length on transgene expression, we conducted an experiment to regulate exogenous gene expression by manipulating the NDR in the transcriptional regulatory region of S. cerevisiae genes. We selected the ±1 nucleosome and NDR sequences between them of six S. cerevisiae genes as transcriptional regulatory elements to drive GFP gene expression. Our findings revealed that under the regulation of long NDR, both the mRNA and protein expression levels of the GFP gene were significantly increased compared to those under short NDR. Furthermore, reducing the long NDR by 80 bp (NDR−) resulted in a significant reduction in the level of GFP gene expression. However, lengthening the short NDR length by 80 bp (NDR+) significantly increased the expression level of the GFP gene. This is attributed to the fact that longer NDR facilitates transcription factor (TF) binding without energy expenditure, thereby enhancing transcription efficiency. In contrast, shorter NDR necessitates the disassembly or sliding of the −1 nucleosome to accommodate TF binding, which consumes energy and reduces the transcription efficiency. These results demonstrate that the expression system constructed using the ±1 nucleosome and NDR sequences can effectively modulate exogenous gene expression, offering a novel design approach for transgene expression control.