Coordinated metabolic transitions during Drosophila embryogenesis and the onset of aerobic glycolysis.

PubMed

Tennessen, Jason M; Bertagnolli, Nicolas M; Evans, Janelle; Sieber, Matt H; Cox, James; Thummel, Carl S

2014-03-12

Rapidly proliferating cells such as cancer cells and embryonic stem cells rely on a specialized metabolic program known as aerobic glycolysis, which supports biomass production from carbohydrates. The fruit fly Drosophila melanogaster also utilizes aerobic glycolysis to support the rapid growth that occurs during larval development. Here we use singular value decomposition analysis of modENCODE RNA-seq data combined with GC-MS-based metabolomic analysis to analyze the changes in gene expression and metabolism that occur during Drosophila embryogenesis, spanning the onset of aerobic glycolysis. Unexpectedly, we find that the most common pattern of co-expressed genes in embryos includes the global switch to glycolytic gene expression that occurs midway through embryogenesis. In contrast to the canonical aerobic glycolytic pathway, however, which is accompanied by reduced mitochondrial oxidative metabolism, the expression of genes involved in the tricarboxylic cycle (TCA cycle) and the electron transport chain are also upregulated at this time. Mitochondrial activity, however, appears to be attenuated, as embryos exhibit a block in the TCA cycle that results in elevated levels of citrate, isocitrate, and α-ketoglutarate. We also find that genes involved in lipid breakdown and β-oxidation are upregulated prior to the transcriptional initiation of glycolysis, but are downregulated before the onset of larval development, revealing coordinated use of lipids and carbohydrates during development. These observations demonstrate the efficient use of nutrient stores to support embryonic development, define sequential metabolic transitions during this stage, and demonstrate striking similarities between the metabolic state of late-stage fly embryos and tumor cells. Copyright © 2014 Tennessen et al.

Geochemical constraints on sources of metabolic energy for chemolithoautotrophy in ultramafic-hosted deep-sea hydrothermal systems.

PubMed

McCollom, Thomas M

2007-12-01

Numerical models are employed to investigate sources of chemical energy for autotrophic microbial metabolism that develop during mixing of oxidized seawater with strongly reduced fluids discharged from ultramafic-hosted hydrothermal systems on the seafloor. Hydrothermal fluids in these systems are highly enriched in H(2) and CH(4) as a result of alteration of ultramafic rocks (serpentinization) in the subsurface. Based on the availability of chemical energy sources, inferences are made about the likely metabolic diversity, relative abundance, and spatial distribution of microorganisms within ultramafic-hosted systems. Metabolic reactions involving H(2) and CH(4), particularly hydrogen oxidation, methanotrophy, sulfate reduction, and methanogenesis, represent the predominant sources of chemical energy during fluid mixing. Owing to chemical gradients that develop from fluid mixing, aerobic metabolisms are likely to predominate in low-temperature environments (<20-30 degrees C), while anaerobes will dominate higher-temperature environments. Overall, aerobic metabolic reactions can supply up to approximately 7 kJ of energy per kilogram of hydrothermal fluid, while anaerobic metabolic reactions can supply about 1 kJ, which is sufficient to support a maximum of approximately 120 mg (dry weight) of primary biomass production by aerobic organisms and approximately 20-30 mg biomass by anaerobes. The results indicate that ultramafic-hosted systems are capable of supplying about twice as much chemical energy as analogous deep-sea hydrothermal systems hosted in basaltic rocks.

Aerobic and anaerobic glucose metabolism of Phytomonas sp. isolated from Euphorbia characias.

PubMed

Chaumont, F; Schanck, A N; Blum, J J; Opperdoes, F R

1994-10-01

Metabolic studies on Phytomonas sp. isolated from the lactiferous tubes of the latex-bearing spurge Euphorbia characias indicate that glucose is the preferred energy and carbon substrate during logarithmic growth. In stationary phase cells glucose consumption was dramatically reduced. Glucose consumption and end-product formation were measured on logarithmically growing cells, both under aerobic (air and 95% O2/5% CO2) and anaerobic (95% N2/5% CO2 and 100% N2) conditions. The rate of glucose consumption slightly increased under anaerobic conditions indicating that Phytomonas lacks a 'reverse Pasteur' effect contrary to the situation encountered in Leishmania major. Major end-products of glucose catabolism under aerobic conditions, detected by enzymatic and NMR measurements, were acetate, ethanol and carbon dioxide and under anaerobic conditions ethanol, glycerol and carbon dioxide. Smaller amounts of pyruvate, succinate, L-malate, L-lactate, phosphoenolpyruvate, alanine and aspartate were also detected.

Effects of muscular and aqua aerobic combined exercise on metabolic indices in elderly women with metabolic syndrome

PubMed Central

Yoo, Yong-Kwon; Kim, Soo-Keun; Song, Min-Sun

2013-01-01

The purpose of this study was to investigate the effects of muscle strengthening exercise using elastic thera-band and aquatic aerobic combined exercise on metabolic syndrome index in elderly with metabolic syndrome. Fifty-four were assigned to muscle strengthening exercise group (n = 19), aquatic aerobic exercise group (n = 19), and combined exercise group (n = 16). The muscle strength exercise, aquatic aerobic exercise and combined exercise were provided three times a week for 12 weeks. Metabolic syndrome indices[Fasting blood glucose, triglyceride, high density lipoprotein cholesterol (HDL-C), systolic blood pressure, diastolic blood pressure and waist circumference] were measured before and after the program. One-way ANOVA, paired t-test and two-way repeated ANOVA were used with the SPSS program for data analysis. There was a significant difference in triglyceride (p < .001), HDL-C (p = .010) and waist circumference (p = .016). Triglyceride and waist circumference was significantly decreased in combined group than muscle strength exercise group and aquatic exercise group. HDL-C was significantly increased in combined group than muscle strength exercise group. The results indicate that combined exercise was more effective in the improvement of dyslipidemia and abdominal obesity. PMID:25566424

Effects of muscular and aqua aerobic combined exercise on metabolic indices in elderly women with metabolic syndrome.

PubMed

Yoo, Yong-Kwon; Kim, Soo-Keun; Song, Min-Sun

2013-12-01

The purpose of this study was to investigate the effects of muscle strengthening exercise using elastic thera-band and aquatic aerobic combined exercise on metabolic syndrome index in elderly with metabolic syndrome. Fifty-four were assigned to muscle strengthening exercise group (n = 19), aquatic aerobic exercise group (n = 19), and combined exercise group (n = 16). The muscle strength exercise, aquatic aerobic exercise and combined exercise were provided three times a week for 12 weeks. Metabolic syndrome indices[Fasting blood glucose, triglyceride, high density lipoprotein cholesterol (HDL-C), systolic blood pressure, diastolic blood pressure and waist circumference] were measured before and after the program. One-way ANOVA, paired t-test and two-way repeated ANOVA were used with the SPSS program for data analysis. There was a significant difference in triglyceride (p < .001), HDL-C (p = .010) and waist circumference (p = .016). Triglyceride and waist circumference was significantly decreased in combined group than muscle strength exercise group and aquatic exercise group. HDL-C was significantly increased in combined group than muscle strength exercise group. The results indicate that combined exercise was more effective in the improvement of dyslipidemia and abdominal obesity.

Evolution of Molybdenum Nitrogenase during the Transition from Anaerobic to Aerobic Metabolism

PubMed Central

Boyd, Eric S.; Costas, Amaya M. Garcia; Hamilton, Trinity L.; Mus, Florence

2015-01-01

ABSTRACT Molybdenum nitrogenase (Nif), which catalyzes the reduction of dinitrogen to ammonium, has modulated the availability of fixed nitrogen in the biosphere since early in Earth's history. Phylogenetic evidence indicates that oxygen (O2)-sensitive Nif emerged in an anaerobic archaeon and later diversified into an aerobic bacterium. Aerobic bacteria that fix N2 have adapted a number of strategies to protect Nif from inactivation by O2, including spatial and temporal segregation of Nif from O2 and respiratory consumption of O2. Here we report the complement of Nif-encoding genes in 189 diazotrophic genomes. We show that the evolution of Nif during the transition from anaerobic to aerobic metabolism was accompanied by both gene recruitment and loss, resulting in a substantial increase in the number of nif genes. While the observed increase in the number of nif genes and their phylogenetic distribution are strongly correlated with adaptation to utilize O2 in metabolism, the increase is not correlated with any of the known O2 protection mechanisms. Rather, gene recruitment appears to have been in response to selective pressure to optimize Nif synthesis to meet fixed N demands associated with aerobic productivity and to more efficiently regulate Nif under oxic conditions that favor protein turnover. Consistent with this hypothesis, the transition of Nif from anoxic to oxic environments is associated with a shift from posttranslational regulation in anaerobes to transcriptional regulation in obligate aerobes and facultative anaerobes. Given that fixed nitrogen typically limits ecosystem productivity, our observations further underscore the dynamic interplay between the evolution of Earth's oxygen, nitrogen, and carbon biogeochemical cycles. IMPORTANCE Molybdenum nitrogenase (Nif), which catalyzes the reduction of dinitrogen to ammonium, has modulated the availability of fixed nitrogen in the biosphere since early in Earth's history. Nif emerged in an anaerobe and

Resistance to Aerobic Exercise Training Causes Metabolic Dysfunction and Reveals Novel Exercise-Regulated Signaling Networks

PubMed Central

Lessard, Sarah J.; Rivas, Donato A.; Alves-Wagner, Ana B.; Hirshman, Michael F.; Gallagher, Iain J.; Constantin-Teodosiu, Dumitru; Atkins, Ryan; Greenhaff, Paul L.; Qi, Nathan R.; Gustafsson, Thomas; Fielding, Roger A.; Timmons, James A.; Britton, Steven L.; Koch, Lauren G.; Goodyear, Laurie J.

2013-01-01

Low aerobic exercise capacity is a risk factor for diabetes and a strong predictor of mortality, yet some individuals are “exercise-resistant” and unable to improve exercise capacity through exercise training. To test the hypothesis that resistance to aerobic exercise training underlies metabolic disease risk, we used selective breeding for 15 generations to develop rat models of low and high aerobic response to training. Before exercise training, rats selected as low and high responders had similar exercise capacities. However, after 8 weeks of treadmill training, low responders failed to improve their exercise capacity, whereas high responders improved by 54%. Remarkably, low responders to aerobic training exhibited pronounced metabolic dysfunction characterized by insulin resistance and increased adiposity, demonstrating that the exercise-resistant phenotype segregates with disease risk. Low responders had impaired exercise-induced angiogenesis in muscle; however, mitochondrial capacity was intact and increased normally with exercise training, demonstrating that mitochondria are not limiting for aerobic adaptation or responsible for metabolic dysfunction in low responders. Low responders had increased stress/inflammatory signaling and altered transforming growth factor-β signaling, characterized by hyperphosphorylation of a novel exercise-regulated phosphorylation site on SMAD2. Using this powerful biological model system, we have discovered key pathways for low exercise training response that may represent novel targets for the treatment of metabolic disease. PMID:23610057

Aerobic glycolysis during brain activation: adrenergic regulation and influence of norepinephrine on astrocytic metabolism.

PubMed

Dienel, Gerald A; Cruz, Nancy F

2016-07-01

Aerobic glycolysis occurs during brain activation and is characterized by preferential up-regulation of glucose utilization compared with oxygen consumption even though oxygen level and delivery are adequate. Aerobic glycolysis is a widespread phenomenon that underlies energetics of diverse brain activities, such as alerting, sensory processing, cognition, memory, and pathophysiological conditions, but specific cellular functions fulfilled by aerobic glycolysis are poorly understood. Evaluation of evidence derived from different disciplines reveals that aerobic glycolysis is a complex, regulated phenomenon that is prevented by propranolol, a non-specific β-adrenoceptor antagonist. The metabolic pathways that contribute to excess utilization of glucose compared with oxygen include glycolysis, the pentose phosphate shunt pathway, the malate-aspartate shuttle, and astrocytic glycogen turnover. Increased lactate production by unidentified cells, and lactate dispersal from activated cells and lactate release from the brain, both facilitated by astrocytes, are major factors underlying aerobic glycolysis in subjects with low blood lactate levels. Astrocyte-neuron lactate shuttling with local oxidation is minor. Blockade of aerobic glycolysis by propranolol implicates adrenergic regulatory processes including adrenal release of epinephrine, signaling to brain via the vagus nerve, and increased norepinephrine release from the locus coeruleus. Norepinephrine has a powerful influence on astrocytic metabolism and glycogen turnover that can stimulate carbohydrate utilization more than oxygen consumption, whereas β-receptor blockade 're-balances' the stoichiometry of oxygen-glucose or -carbohydrate metabolism by suppressing glucose and glycogen utilization more than oxygen consumption. This conceptual framework may be helpful for design of future studies to elucidate functional roles of preferential non-oxidative glucose utilization and glycogen turnover during brain

Metabolic reprogramming during neuronal differentiation from aerobic glycolysis to neuronal oxidative phosphorylation.

PubMed

Zheng, Xinde; Boyer, Leah; Jin, Mingji; Mertens, Jerome; Kim, Yongsung; Ma, Li; Ma, Li; Hamm, Michael; Gage, Fred H; Hunter, Tony

2016-06-10

How metabolism is reprogrammed during neuronal differentiation is unknown. We found that the loss of hexokinase (HK2) and lactate dehydrogenase (LDHA) expression, together with a switch in pyruvate kinase gene splicing from PKM2 to PKM1, marks the transition from aerobic glycolysis in neural progenitor cells (NPC) to neuronal oxidative phosphorylation. The protein levels of c-MYC and N-MYC, transcriptional activators of the HK2 and LDHA genes, decrease dramatically. Constitutive expression of HK2 and LDHA during differentiation leads to neuronal cell death, indicating that the shut-off aerobic glycolysis is essential for neuronal survival. The metabolic regulators PGC-1α and ERRγ increase significantly upon neuronal differentiation to sustain the transcription of metabolic and mitochondrial genes, whose levels are unchanged compared to NPCs, revealing distinct transcriptional regulation of metabolic genes in the proliferation and post-mitotic differentiation states. Mitochondrial mass increases proportionally with neuronal mass growth, indicating an unknown mechanism linking mitochondrial biogenesis to cell size.

Aerobic metabolism on muscle contraction in porcine iris sphincter.

PubMed

Kanda, Hidenori; Kaneda, Takeharu; Kato, Asami; Yogo, Takuya; Harada, Yasuji; Hara, Yasusi; Urakawa, Norimoto; Shimizu, Kazumasa

2016-12-01

Eyes are supplied O 2 through the cornea and vessels of the retina and iris, which are tissues characterized by aerobic metabolism. Meanwhile, there are no reports on the association between iris sphincter contraction and aerobic metabolism. In this paper, we studied the aforementioned association. Eyes from adult pigs of either sex were obtained from a local abattoir. A muscle strip was connected to a transducer to isometrically record the tension. O 2 consumption was measured using a Clark-type polarograph connected to a biological oxygen monitor. Creatine phosphate (PCr) and adenosine triphosphate (ATP) contents were measured in the muscle strips by high-performance liquid chromatography (HPLC). Iris sphincter muscles were measured in resting, contractile or hypoxic phases. Contraction was induced by hyperosmotic 65 mM KCl (H-65K + ) or carbachol (CCh), and hypoxia was induced by aeration with N 2 instead of O 2 or by addition of sodium cyanide (NaCN). H-65K + - and CCh-induced muscle contraction, involved increasing O 2 consumption. Hypoxia and NaCN significantly decreased H-65K + - and CCh-induced muscle contraction and/or O 2 consumption and PCr contents. Our results suggest that the contractile behavior in porcine iris sphincter highly depends on mitogen oxidative metabolism.

Pressure and temperature interactions on aerobic metabolism in migrating silver eels: results in vitro.

PubMed

Scaion, D; Vettier, A; Sébert, P

2008-01-01

The European eel (Anguilla anguilla) migrates (6000 km) from European coast towards the supposed spawning area: the Sargasso Sea. This intensive and sustained swimming activity is performed without feeding and by using essentially red muscle i.e. aerobic metabolism. Temperature and hydrostatic pressure vary during migration and have known effects on energy metabolism, mainly on mitochondrial functioning. We raise the question about the existence of a pressure-temperature combination that optimizes energy metabolism. We have measured the maximal oxygen consumption (MO2) of red muscle fibres of silver eel (migrating stage) in a temperature range (5 to 25 degrees C) covering what can be reasonably expected during the migration. We have combined (random order) three temperatures (5, 15, 25 degrees C) with 5 different pressures steps from 0.1 to 10.1 MPa (corresponding to depths from surface to 1000 m). The results show that when an adequate temperature is chosen as a reference, pressure effects and pressure sensitivity depend on the temperature. Based on the fact that energy budget is limited in migrating eels, we consider that the best conditions are low temperature and high pressure.

Within-Winter Flexibility in Muscle Masses, Myostatin, and Cellular Aerobic Metabolic Intensity in Passerine Birds.

PubMed

Swanson, David L; King, Marisa O; Culver, William; Zhang, Yufeng

Metabolic rates of passerine birds are flexible traits that vary both seasonally and among and within winters. Seasonal variation in summit metabolic rates (M sum = maximum thermoregulatory metabolism) in birds is consistently correlated with changes in pectoralis muscle and heart masses and sometimes with variation in cellular aerobic metabolic intensity, so these traits might also be associated with shorter-term, within-winter variation in metabolic rates. To determine whether these mechanisms are associated with within-winter variation in M sum , we examined the effects of short-term (ST; 0-7 d), medium-term (MT; 14-30 d), and long-term (LT; 30-yr means) temperature variables on pectoralis muscle and heart masses, pectoralis expression of the muscle-growth inhibitor myostatin and its metalloproteinase activators TLL-1 and TLL-2, and pectoralis and heart citrate synthase (CS; an indicator of cellular aerobic metabolic intensity) activities for two temperate-zone resident passerines, house sparrows (Passer domesticus) and dark-eyed juncos (Junco hyemalis). For both species, pectoralis mass residuals were positively correlated with ST temperature variables, suggesting that cold temperatures resulted in increased turnover of pectoralis muscle, but heart mass showed little within-winter variation for either species. Pectoralis mRNA and protein expression of myostatin and the TLLs were only weakly correlated with ST and MT temperature variables, which is largely consistent with trends in muscle masses for both species. Pectoralis and heart CS activities showed weak and variable trends with ST temperature variables in both species, suggesting only minor effects of temperature variation on cellular aerobic metabolic intensity. Thus, neither muscle or heart masses, regulation by the myostatin system, nor cellular aerobic metabolic intensity varied consistently with winter temperature, suggesting that other factors regulate within-winter metabolic variation in these birds.

Energy expenditure during tennis play: a preliminary video analysis and metabolic model approach.

PubMed

Botton, Florent; Hautier, Christophe; Eclache, Jean-Paul

2011-11-01

The aim of this study was to estimate, using video analysis, what proportion of the total energy expenditure during a tennis match is accounted for by aerobic and anaerobic metabolism, respectively. The method proposed involved estimating the metabolic power (MP) of 5 activities, which are inherent to tennis: walking, running, hitting the ball, serving, and sitting down to rest. The energy expenditure concerned was calculated by sequencing the activity by video analysis. A bioenergetic model calculated the aerobic energy expenditure (EEO2mod) in terms of MP, and the anaerobic energy expenditure was calculated by subtracting this (MP - EEO2mod). Eight tennis players took part in the experiment as subjects (mean ± SD: age 25.2 ± 1.9 years, weight 79.3 ± 10.8 kg, VO2max 54.4 ± 5.1 ml·kg(-1)·min(-1)). The players started off by participating in 2 games while wearing the K4b2, with their activity profile measured by the video analysis system, and then by playing a set without equipment but with video analysis. There was no significant difference between calculated and measured oxygen consumptions over the 16 games (p = 0.763), and these data were strongly related (r = 0.93, p < 0.0001). The EEO2mod was quite weak over all the games (49.4 ± 4.8% VO2max), whereas the MP during points was up to 2 or 3 times the VO2max. Anaerobic metabolism reached 32% of the total energy expenditure across all the games 67% for points and 95% for hitting the ball. This method provided a good estimation of aerobic energy expenditure and made it possible to calculate the anaerobic energy expenditure. This could make it possible to estimate the metabolic intensity of training sessions and matches using video analysis.

Modeling central metabolism and energy biosynthesis across microbial life.

PubMed

Edirisinghe, Janaka N; Weisenhorn, Pamela; Conrad, Neal; Xia, Fangfang; Overbeek, Ross; Stevens, Rick L; Henry, Christopher S

2016-08-08

Automatically generated bacterial metabolic models, and even some curated models, lack accuracy in predicting energy yields due to poor representation of key pathways in energy biosynthesis and the electron transport chain (ETC). Further compounding the problem, complex interlinking pathways in genome-scale metabolic models, and the need for extensive gapfilling to support complex biomass reactions, often results in predicting unrealistic yields or unrealistic physiological flux profiles. To overcome this challenge, we developed methods and tools ( http://coremodels.mcs.anl.gov ) to build high quality core metabolic models (CMM) representing accurate energy biosynthesis based on a well studied, phylogenetically diverse set of model organisms. We compare these models to explore the variability of core pathways across all microbial life, and by analyzing the ability of our core models to synthesize ATP and essential biomass precursors, we evaluate the extent to which the core metabolic pathways and functional ETCs are known for all microbes. 6,600 (80 %) of our models were found to have some type of aerobic ETC, whereas 5,100 (62 %) have an anaerobic ETC, and 1,279 (15 %) do not have any ETC. Using our manually curated ETC and energy biosynthesis pathways with no gapfilling at all, we predict accurate ATP yields for nearly 5586 (70 %) of the models under aerobic and anaerobic growth conditions. This study revealed gaps in our knowledge of the central pathways that result in 2,495 (30 %) CMMs being unable to produce ATP under any of the tested conditions. We then established a methodology for the systematic identification and correction of inconsistent annotations using core metabolic models coupled with phylogenetic analysis. We predict accurate energy yields based on our improved annotations in energy biosynthesis pathways and the implementation of diverse ETC reactions across the microbial tree of life. We highlighted missing annotations that were essential to

STRATEGIES FOR THE AEROBIC CO-METABOLISM OF CHLORINATED SOLVENTS. (R825689C019)

EPA Science Inventory

Abstract

Recent field and laboratory studies have evaluated the potential for aerobic co-metabolism of chlorinated solvents. Different co-metabolic substrates and different methods of application have been tried, including growing indigenous microbes in situ, an...

Temperature acclimation rate of aerobic scope and feeding metabolism in fishes: implications in a thermally extreme future

PubMed Central

Sandblom, Erik; Gräns, Albin; Axelsson, Michael; Seth, Henrik

2014-01-01

Temperature acclimation may offset the increased energy expenditure (standard metabolic rate, SMR) and reduced scope for activity (aerobic scope, AS) predicted to occur with local and global warming in fishes and other ectotherms. Yet, the time course and mechanisms of this process is little understood. Acclimation dynamics of SMR, maximum metabolic rate, AS and the specific dynamic action of feeding (SDA) were determined in shorthorn sculpin (Myoxocephalus scorpius) after transfer from 10°C to 16°C. SMR increased in the first week by 82% reducing AS to 55% of initial values, while peak postprandial metabolism was initially greater. This meant that the estimated AS during peak SDA approached zero, constraining digestion and leaving little room for additional aerobic processes. After eight weeks at 16°C, SMR was restored, while AS and the estimated AS during peak SDA recovered partly. Collectively, this demonstrated a considerable capacity for metabolic thermal compensation, which should be better incorporated into future models on organismal responses to climate change. A mathematical model based on the empirical data suggested that phenotypes with fast acclimation rates may be favoured by natural selection as the accumulated energetic cost of a slow acclimation rate increases in a warmer future with exacerbated thermal variations. PMID:25232133

A Shift in the Thermoregulatory Curve as a Result of Selection for High Activity-Related Aerobic Metabolism

PubMed Central

Stawski, Clare; Koteja, Paweł; Sadowska, Edyta T.

2017-01-01

According to the “aerobic capacity model,” endothermy in birds and mammals evolved as a result of natural selection favoring increased persistent locomotor activity, fuelled by aerobic metabolism. However, this also increased energy expenditure even during rest, with the lowest metabolic rates occurring in the thermoneutral zone (TNZ) and increasing at ambient temperatures (Ta) below and above this range, depicted by the thermoregulatory curve. In our experimental evolution system, four lines of bank voles (Myodes glareolus) have been selected for high swim-induced aerobic metabolism and four unselected lines have been maintained as a control. In addition to a 50% higher rate of oxygen consumption during swimming, the selected lines have also evolved a 7.3% higher mass-adjusted basal metabolic rate. Therefore, we asked whether voles from selected lines would also display a shift in the thermoregulatory curve and an increased body temperature (Tb) during exposure to high Ta. To test these hypotheses we measured the RMR and Tb of selected and control voles at Ta from 10 to 34°C. As expected, RMR within and around the TNZ was higher in selected lines. Further, the Tb of selected lines within the TNZ was greater than the Tb of control lines, particularly at the maximum measured Ta of 34°C, suggesting that selected voles are more prone to hyperthermia. Interestingly, our results revealed that while the slope of the thermoregulatory curve below the lower critical temperature (LCT) is significantly lower in the selected lines, the LCT (26.1°C) does not differ. Importantly, selected voles also evolved a higher maximum thermogenesis, but thermal conductance did not increase. As a consequence, the minimum tolerated temperature, calculated from an extrapolation of the thermoregulatory curve, is 8.4°C lower in selected (−28.6°C) than in control lines (−20.2°C). Thus, selection for high aerobic exercise performance, even though operating under thermally neutral

A Shift in the Thermoregulatory Curve as a Result of Selection for High Activity-Related Aerobic Metabolism.

PubMed

Stawski, Clare; Koteja, Paweł; Sadowska, Edyta T

2017-01-01

According to the "aerobic capacity model," endothermy in birds and mammals evolved as a result of natural selection favoring increased persistent locomotor activity, fuelled by aerobic metabolism. However, this also increased energy expenditure even during rest, with the lowest metabolic rates occurring in the thermoneutral zone (TNZ) and increasing at ambient temperatures (T a ) below and above this range, depicted by the thermoregulatory curve. In our experimental evolution system, four lines of bank voles ( Myodes glareolus ) have been selected for high swim-induced aerobic metabolism and four unselected lines have been maintained as a control. In addition to a 50% higher rate of oxygen consumption during swimming, the selected lines have also evolved a 7.3% higher mass-adjusted basal metabolic rate. Therefore, we asked whether voles from selected lines would also display a shift in the thermoregulatory curve and an increased body temperature (T b ) during exposure to high T a . To test these hypotheses we measured the RMR and T b of selected and control voles at T a from 10 to 34°C. As expected, RMR within and around the TNZ was higher in selected lines. Further, the T b of selected lines within the TNZ was greater than the T b of control lines, particularly at the maximum measured T a of 34°C, suggesting that selected voles are more prone to hyperthermia. Interestingly, our results revealed that while the slope of the thermoregulatory curve below the lower critical temperature (LCT) is significantly lower in the selected lines, the LCT (26.1°C) does not differ. Importantly, selected voles also evolved a higher maximum thermogenesis, but thermal conductance did not increase. As a consequence, the minimum tolerated temperature, calculated from an extrapolation of the thermoregulatory curve, is 8.4°C lower in selected (-28.6°C) than in control lines (-20.2°C). Thus, selection for high aerobic exercise performance, even though operating under thermally

Increased ratio between anaerobic and aerobic metabolism in lymphocytes from hyperthyroid patients.

PubMed

Valdemarsson, S; Monti, M

1994-03-01

While an increased oxygen consumption is accepted as one consequence of hyperthyroidism, only few data are available on the role of anaerobic processes for the increased metabolic activity in this disease. In this study we evaluated the relative importance of anaerobic and aerobic metabolism for the metabolic activity in lymphocytes from patients before and after treatment for hyperthyroidism. Total lymphocyte heat production rate (P), reflecting total cell metabolic activity, was determined in a plasma lymphocyte suspension using direct microcalorimetry. The contribution from aerobic metabolism (O2-P) was calculated from the product of the lymphocyte oxygen consumption rate and the enthalpy change for glucose combustion, and the anaerobic contribution as the difference between P and O2-P. The total lymphocyte heat production rate P was 3.37 +/- 0.25 (SEM) pW/cell (N = 11) before and 2.50 +/- 0.11 pW/cell (N = 10) after treatment for hyperthyroidism (p < 0.01) as compared to 2.32 +/- 0.10 pW/cell in a control group (N = 18). The aerobic component O2-P amounted to 1.83 +/- 0.11 pW/cell in the patient group before and 1.83 +/- 0.08 pW/cell after treatment and to 1.71 +/- 0.16 pW/cell in 10 controls. Out of P, the O2-P component corresponded to 56.8 +/- 4.4% in the hyperthyroid state and to 73.7 +/- 3.2% after treatment (p < 0.01) as compared to 73.4 +/- 4.4% in the 10 euthyroid controls. It was concluded that the increased metabolic activity demonstrated in lymphocytes from hyperthyroid patients cannot be explained by an increased oxygen-dependent consumption.(ABSTRACT TRUNCATED AT 250 WORDS)

Metabolic reprogramming during neuronal differentiation from aerobic glycolysis to neuronal oxidative phosphorylation

PubMed Central

Zheng, Xinde; Boyer, Leah; Jin, Mingji; Mertens, Jerome; Kim, Yongsung; Ma, Li; Ma, Li; Hamm, Michael; Gage, Fred H; Hunter, Tony

2016-01-01

How metabolism is reprogrammed during neuronal differentiation is unknown. We found that the loss of hexokinase (HK2) and lactate dehydrogenase (LDHA) expression, together with a switch in pyruvate kinase gene splicing from PKM2 to PKM1, marks the transition from aerobic glycolysis in neural progenitor cells (NPC) to neuronal oxidative phosphorylation. The protein levels of c-MYC and N-MYC, transcriptional activators of the HK2 and LDHA genes, decrease dramatically. Constitutive expression of HK2 and LDHA during differentiation leads to neuronal cell death, indicating that the shut-off aerobic glycolysis is essential for neuronal survival. The metabolic regulators PGC-1α and ERRγ increase significantly upon neuronal differentiation to sustain the transcription of metabolic and mitochondrial genes, whose levels are unchanged compared to NPCs, revealing distinct transcriptional regulation of metabolic genes in the proliferation and post-mitotic differentiation states. Mitochondrial mass increases proportionally with neuronal mass growth, indicating an unknown mechanism linking mitochondrial biogenesis to cell size. DOI: http://dx.doi.org/10.7554/eLife.13374.001 PMID:27282387

Mitochondria in Cancer Energy Metabolism

PubMed Central

2015-01-01

Cancer is a disease characterized by uncontrolled growth. Metabolic demands to sustain rapid proliferation must be compelling since aerobic glycolysis is the first as well as the most commonly shared characteristic of cancer. During the last decade, the significance of metabolic reprogramming of cancer has been at the center of attention. Nonetheless, despite all the knowledge gained on cancer biology, the field is not able to reach agreement on the issue of mitochondria: Are damaged mitochondria the cause for aerobic glycolysis in cancer? Warburg proposed the damaged mitochondria theory over 80 years ago; the field has been testing the theory equally long. In this review, we will discuss alterations in metabolic fluxes of cancer cells, and provide an opinion on the damaged mitochondria theory. PMID:26877834

Temperature acclimation rate of aerobic scope and feeding metabolism in fishes: implications in a thermally extreme future.

PubMed

Sandblom, Erik; Gräns, Albin; Axelsson, Michael; Seth, Henrik

2014-11-07

Temperature acclimation may offset the increased energy expenditure (standard metabolic rate, SMR) and reduced scope for activity (aerobic scope, AS) predicted to occur with local and global warming in fishes and other ectotherms. Yet, the time course and mechanisms of this process is little understood. Acclimation dynamics of SMR, maximum metabolic rate, AS and the specific dynamic action of feeding (SDA) were determined in shorthorn sculpin (Myoxocephalus scorpius) after transfer from 10°C to 16°C. SMR increased in the first week by 82% reducing AS to 55% of initial values, while peak postprandial metabolism was initially greater. This meant that the estimated AS during peak SDA approached zero, constraining digestion and leaving little room for additional aerobic processes. After eight weeks at 16°C, SMR was restored, while AS and the estimated AS during peak SDA recovered partly. Collectively, this demonstrated a considerable capacity for metabolic thermal compensation, which should be better incorporated into future models on organismal responses to climate change. A mathematical model based on the empirical data suggested that phenotypes with fast acclimation rates may be favoured by natural selection as the accumulated energetic cost of a slow acclimation rate increases in a warmer future with exacerbated thermal variations. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Temperature dependent growth, feeding, nutritional condition and aerobic metabolism of juvenile spiny lobster, Sagmariasus verreauxi.

PubMed

Fitzgibbon, Quinn P; Simon, Cedric J; Smith, Gregory G; Carter, Chris G; Battaglene, Stephen C

2017-05-01

We examined the effects of temperature on the growth, feeding, nutritional condition and aerobic metabolism of juvenile spiny lobster, Sagmariasus verreauxi, in order to determine if temperature acclimated aerobic scope correlates with optimum for growth and to establish the thermal tolerance window for this emerging aquaculture species. Juvenile lobsters (initial weight=10.95±0.47g) were reared (n=7) at temperatures from 11.0 to 28.5°C for 145days. All lobsters survived from 14.5 to 25.0°C while survival was reduced at 11.0°C (86%) and all lobsters died at 28.5°C. Lobster specific growth rate and specific feed consumption displayed a unimodal response with temperature, peaking at 21.5°C. Lobster standard, routine and maximum metabolic rates, and aerobic scope all increased exponentially up to maximum non-lethal temperature. Optimum temperature for growth did not correspond to that for maximum aerobic scope suggesting that aerobic scope is not an effective predictor of the thermal optimum of spiny lobsters. Plateauing of specific feed consumption beyond 21.5°C suggests that temperature dependent growth of lobsters is limited by capacity to ingest or digest sufficient food to meet increasing maintenance metabolic demands at high temperatures. The nutritional condition of lobsters was not influenced by temperature and feed conversion ratio was improved at lower temperatures. These findings add to a growing body of evidence questioning the generality of aerobic scope to describe the physiological thermal boundaries of aquatic ectotherms and suggest that feed intake plays a crucial role in regulating performance at thermal extremes. Copyright © 2017 Elsevier Inc. All rights reserved.

The beneficial effects of aerobic and concurrent training on metabolic profile and body composition after detraining: a 1-year follow-up in postmenopausal women.

PubMed

Rossi, F E; Diniz, T A; Neves, L M; Fortaleza, A C S; Gerosa-Neto, J; Inoue, D S; Buonani, C; Cholewa, J M; Lira, F S; Freitas, I F

2017-05-01

Aerobic and concurrent training (CT, aerobic and strength training) improves body composition and metabolic profile; however, it is not known whether these positive outcomes acquired after aerobic or CT are maintained long term (⩾6 months) after program interruption in postmenopausal women. This study investigated the changes in total and appendicular body composition, bone mineral density and metabolic profile following 16 weeks of aerobic or CT, and through 6 months and 1 year of detraining in postmenopausal women. In total, 60 postmenopausal women were divided into the following groups: aerobic (AT), aerobic plus strength training (CT) and control group (CG), and 31 participants were assessed for the 1 year follow-up. Body composition and bone mineral density were evaluated by dual-energy X-ray absorptiometry (DXA), and total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triacylglycerol, glucose, insulin, leptin, adiponectin and plasminogen activator inhibitor-1 (PAI-1) were assessed. There were main effects of time for arm fat mass, arm lean mass and trunk lean mass (P<0.05). There was a statistical difference between AT and CG for leg fat mass and percentage of fat (P<0.05). After 6 months of detraining, leg lean mass decreased in relation to post-intervention, and there was a statistically significant interaction for total and appendicular lean mass (P<0.05). There were differences between CT and CG in glucose and between AT and CG in glucose and triacylglycerol (P<0.05). A duration of 16 weeks of aerobic or CT improved total and appendicular body composition and metabolic profile but after 6 months of detraining, leg lean mass returned to the values obtained pre-training in CT.

Modeling central metabolism and energy biosynthesis across microbial life

DOE PAGES

Edirisinghe, Janaka N.; Weisenhorn, Pamela; Conrad, Neal; ...

2016-08-08

Here, automatically generated bacterial metabolic models, and even some curated models, lack accuracy in predicting energy yields due to poor representation of key pathways in energy biosynthesis and the electron transport chain (ETC). Further compounding the problem, complex interlinking pathways in genome-scale metabolic models, and the need for extensive gapfilling to support complex biomass reactions, often results in predicting unrealistic yields or unrealistic physiological flux profiles. As a result, to overcome this challenge, we developed methods and tools to build high quality core metabolic models (CMM) representing accurate energy biosynthesis based on a well studied, phylogenetically diverse set of modelmore » organisms. We compare these models to explore the variability of core pathways across all microbial life, and by analyzing the ability of our core models to synthesize ATP and essential biomass precursors, we evaluate the extent to which the core metabolic pathways and functional ETCs are known for all microbes. 6,600 (80 %) of our models were found to have some type of aerobic ETC, whereas 5,100 (62 %) have an anaerobic ETC, and 1,279 (15 %) do not have any ETC. Using our manually curated ETC and energy biosynthesis pathways with no gapfilling at all, we predict accurate ATP yields for nearly 5586 (70 %) of the models under aerobic and anaerobic growth conditions. This study revealed gaps in our knowledge of the central pathways that result in 2,495 (30 %) CMMs being unable to produce ATP under any of the tested conditions. We then established a methodology for the systematic identification and correction of inconsistent annotations using core metabolic models coupled with phylogenetic analysis. In conclusion, we predict accurate energy yields based on our improved annotations in energy biosynthesis pathways and the implementation of diverse ETC reactions across the microbial tree of life. We highlighted missing annotations that were essential

Modeling central metabolism and energy biosynthesis across microbial life

DOE Office of Scientific and Technical Information (OSTI.GOV)

Edirisinghe, Janaka N.; Weisenhorn, Pamela; Conrad, Neal

Here, automatically generated bacterial metabolic models, and even some curated models, lack accuracy in predicting energy yields due to poor representation of key pathways in energy biosynthesis and the electron transport chain (ETC). Further compounding the problem, complex interlinking pathways in genome-scale metabolic models, and the need for extensive gapfilling to support complex biomass reactions, often results in predicting unrealistic yields or unrealistic physiological flux profiles. As a result, to overcome this challenge, we developed methods and tools to build high quality core metabolic models (CMM) representing accurate energy biosynthesis based on a well studied, phylogenetically diverse set of modelmore » organisms. We compare these models to explore the variability of core pathways across all microbial life, and by analyzing the ability of our core models to synthesize ATP and essential biomass precursors, we evaluate the extent to which the core metabolic pathways and functional ETCs are known for all microbes. 6,600 (80 %) of our models were found to have some type of aerobic ETC, whereas 5,100 (62 %) have an anaerobic ETC, and 1,279 (15 %) do not have any ETC. Using our manually curated ETC and energy biosynthesis pathways with no gapfilling at all, we predict accurate ATP yields for nearly 5586 (70 %) of the models under aerobic and anaerobic growth conditions. This study revealed gaps in our knowledge of the central pathways that result in 2,495 (30 %) CMMs being unable to produce ATP under any of the tested conditions. We then established a methodology for the systematic identification and correction of inconsistent annotations using core metabolic models coupled with phylogenetic analysis. In conclusion, we predict accurate energy yields based on our improved annotations in energy biosynthesis pathways and the implementation of diverse ETC reactions across the microbial tree of life. We highlighted missing annotations that were essential

Aerobic metabolism on muscle contraction in porcine gastric smooth muscle.

PubMed

Kanda, Hidenori; Kaneda, Takeharu; Nagai, Yuta; Urakawa, Norimoto; Shimizu, Kazumasa

2018-05-18

Exposure to chronic hypoxic conditions causes various gastric diseases, including gastric ulcers. It has been suggested that gastric smooth muscle contraction is associated with aerobic metabolism. However, there are no reports on the association between gastric smooth muscle contraction and aerobic metabolism, and we have investigated this association in the present study. High K + - and carbachol (CCh)-induced muscle contractions involved increasing O 2 consumption. Aeration with N 2 (hypoxia) and NaCN significantly decreased high K + - and CCh-induced muscle contraction and O 2 consumption. In addition, hypoxia and NaCN significantly decreased creatine phosphate (PCr) contents in the presence of high K + . Moreover, decrease in CCh-induced contraction and O 2 consumption was greater than that of high K + . Our results suggest that hypoxia and NaCN inhibit high K + - and CCh-induced contractions in gastric fundus smooth muscles by decreasing O 2 consumption and intracellular PCr content. However, the inhibition of CCh-induced muscle contraction was greater than that of high K + -induced muscle contraction.

[The 18F-FDG myocardial metabolic imaging in twenty seven pilots with regular aerobic training].

PubMed

Fang, Ting-Zheng; Zhu, Jia-Rui; Chuan, Ling; Zhao, Wen-Rui; Xu, Gen-Xiang; Yang, Min-Fu; He, Zuo-Xiang

2009-02-01

To evaluate the characteristics of myocardial (18)F-FDG imaging in pilots with regular aerobic exercise training. Twenty seven healthy male pilots with regular aerobic exercise training were included in this study. The subjects were divided into fasting (n = 17) or non-fasting group (n = 10). Fluorine-18-labeled deoxyglucose and Tc-99m-sestamibi dual-nuclide myocardial imaging were obtained at rest and at target heart rate during bicycle ergometer test. The exercise and rest myocardial perfusion imaging were analyzed for myocardial ischemia presence. The myocardial metabolism imaging was analyzed with the visual semi-quantitative analyses model of seventeen segments. The secondary-extreme heart rate (195-age) was achieved in all subjects. There was no myocardial ischemia in all perfusion imaging. In the visual qualitative analyses, four myocardial metabolism imaging failed in the fasting group while one failed in the non-fasting group (P > 0.05). In the visual semi-quantitative analyses, myocardial metabolism imaging scores at rest or exercise in all segments were similar between two groups (P > 0.05). In the fasting group, the myocardial metabolism imaging scores during exercise were significantly higher than those at rest in 6 segments (P < 0.05). In the non-fasting group, the scores of 3 exercise myocardial metabolism imaging were significantly higher than those at rest (P < 0.05). Satisfactory high-quality myocardial metabolism imaging could be obtained at fasting and exercise situations in subjects with regular aerobic exercise.

The effect of aerobic exercise and starvation on growth performance and postprandial metabolic response in juvenile southern catfish (Silurus meridionalis).

PubMed

Li, Xiu-Ming; Liu, Li; Yuan, Jian-Ming; Xiao, Yuan-Yuan; Fu, Shi-Jian; Zhang, Yao-Guang

2016-03-01

To investigate the effects of aerobic exercise and starvation on growth performance, postprandial metabolic response and their interaction in a sedentary fish species, either satiation-fed or starved juvenile southern catfish (Silurus meridionalis) were exercised at 25 °C under three water velocities, i.e., nearly still water (control), 1 body length (bl) s(-1) and 2 bl s(-1), for eight weeks. Then, the feed intake (FI), food conversion efficiency (FCE), specific growth rate (SGR), morphological parameters, resting ṀO2 (ṀO2rest) and postprandial ṀO2 responses of the experimental fish were measured. Exercise at a low velocity (1 bl s(-1)) showed no effect on any growth performance parameter, whereas exercise at a high velocity (2 bl s(-1)) exhibited higher FI but similar SGR due to the extra energy expenditure from swimming and consequent decreased FCE. Starvation led to a significant body mass loss, whereas the effect intensified in both exercise groups. Exercise resulted in improved cardio-respiratory capacity, as indicated by increased gill and heart indexes, whereas it exhibited no effect on resting and postprandial metabolism in S. meridionalis. The starved fish displayed significantly larger heart, gill and digestive tract indexes compared with the feeding fish, suggesting selective maintenance of cardio-respiratory and digestive function in this fish species during starvation. However, starved fish still exhibited impaired digestive performance, as evidenced by the prolonged duration and low postprandial metabolic increase, and this effect was further exacerbated in both the 1 and 2 bl s(-1) exercise groups. These data suggest the following: (1) aerobic exercise produced no improvement in growth performance but may have led to the impairment of growth under insufficient food conditions; (2) the mass of different organs and tissues responded differently to aerobic exercise and starvation due to the different physiological roles they play; and (3

Exploration and comparison of inborn capacity of aerobic and anaerobic metabolisms of Saccharomyces cerevisiae for microbial electrical current production.

PubMed

Mao, Longfei; Verwoerd, Wynand S

2013-01-01

Saccharomyces cerevisiae possesses numerous advantageous biological features, such as being robust, easily handled, mostly non-pathogenic and having high catabolic rates, etc., which can be considered as merits for being used as a promising biocatalyst in microbial fuel cells (MFCs) for electricity generation. Previous studies have developed efficient MFC configurations to convert metabolic electron shuttles, such as cytoplasmic NADH, into usable electric current. However, no studies have elucidated the maximum potential of S. cerevisiae for current output and the underlying metabolic pathways, resulting from the interaction of thousands of reactions inside the cell during MFC operation. To address these two key issues, this study used in silico metabolic engineering techniques, flux balance analysis (FBA), and flux variability analysis with target flux minimization (FATMIN), to model the metabolic perturbation of S. cerevisiae under the MFC-energy extraction. The FBA results showed that, in the cytoplasmic NADH-dependent mediated electron transfer (MET) mode, S. cerevisiae had a potential to produce currents at up to 5.781 A/gDW for the anaerobic and 6.193 A/gDW for the aerobic environments. The FATMIN results showed that the aerobic and anaerobic metabolisms are resilient, relying on six and five contributing reactions respectively for high current production. Two reactions, catalyzed by glutamate dehydrogenase (NAD) (EC 1.4.1.3) and methylene tetrahydrofolate dehydrogenase (NAD) (EC 1.5.1.5), were shared in both current-production modes and contributed to over 80% of the identified maximum current outputs. It is also shown that the NADH regeneration was much less energy costly than biomass production rate. Taken together, our finding suggests that S. cerevisiae should receive more research effort for MFC electricity production.

The effect of chlorpyrifos on thermogenic capacity of bank voles selected for increased aerobic exercise metabolism.

PubMed

Dheyongera, Geoffrey; Grzebyk, Katherine; Rudolf, Agata M; Sadowska, Edyta T; Koteja, Paweł

2016-04-01

Agro-chemicals potentially cause adverse effects in non-target organisms. The rate of animal energy metabolism can influence their susceptibility to pesticides by influencing food consumption, biotransformation and elimination rates of toxicants. We used experimental evolution to study the effects of inherent differences in energy metabolism rate and exposure to the organophosphate insecticide, chlorpyrifos (CPF) on thermogenic capacity in a wild rodent, the bank vole (Myodes = Clethrionomys glareolus). The voles were sampled from four replicate lines selected for high swim-induced aerobic metabolism (A) and four unselected control (C) lines. Thermogenic capacity, measured as the maximum cold-induced rate of oxygen consumption (VO2cold), was higher in the A - than C lines, and it decreased after continuous exposure to CPF via food or after a single dose administered via oral gavage, but only when measured shortly after exposure. VO2cold measured 24 h after repeated exposure was not affected. In addition, gavage with a single dose led to decreased food consumption and loss in body mass. Importantly, the adverse effects of CPF did not differ between the selected and control lines. Therefore, exposure to CPF has adverse effects on thermoregulatory performance and energy balance in this species. The effects are short-lived and their magnitude is not associated with the inherent level of energy metabolism. Even without severe symptoms of poisoning, fitness can be compromised under harsh environmental conditions, such as cold and wet weather. Copyright © 2016. Published by Elsevier Ltd.

Biochemistry and Evolution of Anaerobic Energy Metabolism in Eukaryotes

PubMed Central

Müller, Miklós; Mentel, Marek; van Hellemond, Jaap J.; Henze, Katrin; Woehle, Christian; Gould, Sven B.; Yu, Re-Young; van der Giezen, Mark

2012-01-01

Summary: Major insights into the phylogenetic distribution, biochemistry, and evolutionary significance of organelles involved in ATP synthesis (energy metabolism) in eukaryotes that thrive in anaerobic environments for all or part of their life cycles have accrued in recent years. All known eukaryotic groups possess an organelle of mitochondrial origin, mapping the origin of mitochondria to the eukaryotic common ancestor, and genome sequence data are rapidly accumulating for eukaryotes that possess anaerobic mitochondria, hydrogenosomes, or mitosomes. Here we review the available biochemical data on the enzymes and pathways that eukaryotes use in anaerobic energy metabolism and summarize the metabolic end products that they generate in their anaerobic habitats, focusing on the biochemical roles that their mitochondria play in anaerobic ATP synthesis. We present metabolic maps of compartmentalized energy metabolism for 16 well-studied species. There are currently no enzymes of core anaerobic energy metabolism that are specific to any of the six eukaryotic supergroup lineages; genes present in one supergroup are also found in at least one other supergroup. The gene distribution across lineages thus reflects the presence of anaerobic energy metabolism in the eukaryote common ancestor and differential loss during the specialization of some lineages to oxic niches, just as oxphos capabilities have been differentially lost in specialization to anoxic niches and the parasitic life-style. Some facultative anaerobes have retained both aerobic and anaerobic pathways. Diversified eukaryotic lineages have retained the same enzymes of anaerobic ATP synthesis, in line with geochemical data indicating low environmental oxygen levels while eukaryotes arose and diversified. PMID:22688819

Assessment of physical activity, energy expenditure and energy intakes of young men practicing aerobic sports.

PubMed

Wierniuk, Alicja; Włodarek, Dariusz

2014-01-01

Adequate nutrition and energy intake play key rule during the training period and recovery time. The assessment of athlete's energetic needs should be calculated individually, based on personal energy expenditure and Sense Wear PRO3 Armband (SWA) mobile monitor is a useful tool to achieve this goal. However, there is still few studies conducted with use of this monitor. To assess individual energy needs of athletes by use of SWA and to determine whether their energy intake fulfils the body's energy expenditure. Subjects were 15 male students attending Military University of Technology in Warsaw, aged 19-24 years, practicing aerobic. The average body mass was 80.7 ± 7.7 kg and average height was 186.9 ± 5.2 cm, (BMI 23.09 ± 1.85 kg/m2). Assessment of physical activity and energy expenditure (TEE) was established using SWA, which was placed on the back side of dominant hand and worn continuously for 48 hours (during the training and non-training day). The presented results are the average values of these 2 days. Assessment of athletes' physical activity level was established by use of metabolic equivalent of task (MET) and number of steps (NS). Estimation of energy intake was based on three-day dietary recalls (two weekdays and one day of the weekend), evaluated using the Polish Software 'Energia' package. The average TEE of examined athletes was 3877 ± 508 kcal/day and almost half of this energy was spend on physical activity (1898 ± 634 kcal/day). The number of steps was on average 19498 ± 5407 and average MET was 2.05 ± 2.09. The average daily energy intake was 2727 ± 576 kcal. Athletes consumed inadequate amount of energy in comparison to their energy expenditure. Examined group did not have an adequate knowledge about their energy requirement, which shows the need of nutritional consulting and education among these athletes. athletes, aerobic sports, energy expenditure, energy intake.

Exploration and comparison of inborn capacity of aerobic and anaerobic metabolisms of Saccharomyces cerevisiae for microbial electrical current production

PubMed Central

Mao, Longfei; Verwoerd, Wynand S

2013-01-01

Saccharomyces cerevisiae possesses numerous advantageous biological features, such as being robust, easily handled, mostly non-pathogenic and having high catabolic rates, etc., which can be considered as merits for being used as a promising biocatalyst in microbial fuel cells (MFCs) for electricity generation. Previous studies have developed efficient MFC configurations to convert metabolic electron shuttles, such as cytoplasmic NADH, into usable electric current. However, no studies have elucidated the maximum potential of S. cerevisiae for current output and the underlying metabolic pathways, resulting from the interaction of thousands of reactions inside the cell during MFC operation. To address these two key issues, this study used in silico metabolic engineering techniques, flux balance analysis (FBA), and flux variability analysis with target flux minimization (FATMIN), to model the metabolic perturbation of S. cerevisiae under the MFC-energy extraction. The FBA results showed that, in the cytoplasmic NADH-dependent mediated electron transfer (MET) mode, S. cerevisiae had a potential to produce currents at up to 5.781 A/gDW for the anaerobic and 6.193 A/gDW for the aerobic environments. The FATMIN results showed that the aerobic and anaerobic metabolisms are resilient, relying on six and five contributing reactions respectively for high current production. Two reactions, catalyzed by glutamate dehydrogenase (NAD) (EC 1.4.1.3) and methylene tetrahydrofolate dehydrogenase (NAD) (EC 1.5.1.5), were shared in both current-production modes and contributed to over 80% of the identified maximum current outputs. It is also shown that the NADH regeneration was much less energy costly than biomass production rate. Taken together, our finding suggests that S. cerevisiae should receive more research effort for MFC electricity production. PMID:23969939

Combined Aerobic/Strength Training and Energy Expenditure in Older Women

PubMed Central

Hunter, Gary R.; Bickel, C. Scott; Fisher, Gordon; Neumeier, William; McCarthy, John

2013-01-01

Purpose To examine the effects of three different frequencies of combined resistance and aerobic training on total energy expenditure (TEE) and activity related energy expenditure (AEE) in a group of older adults. Methods Seventy-two women, 60 – 74 years old, were randomly assigned to one of three groups: 1 day/week of aerobic and 1 day/week of resistance (1+1); 2 days/week of aerobic and 2 days/week resistance (2+2); or 3 days/week aerobic and 3 days/week resistance (3+3). Body composition (DXA), feeling of fatigue, depression, and vigor (questionnaire), strength (1RM), serum cytokines (ELISA), maximal oxygen uptake (progressive treadmill test), resting energy expenditure, and TEE were measured before and after 16 weeks of training. Aerobic training consisted of 40 minutes of aerobic exercise at 80% maximum heart rate and resistance training consisted of 2 sets of 10 repetitions for 10 different exercises at 80% of one repetition maximum. Results All groups increased fat free mass, strength and aerobic fitness and decreased fat mass. No changes were observed in cytokines or perceptions of fatigue/depression. No time by group interaction was found for any fitness/body composition variable. TEE and AEE increased with the 2+2 group but not with the other two groups. Non-exercise training AEE (NEAT) increased significantly in the 2+2 group (+200 kcal/day), group 1×1 showed a trend for an increase (+68 kcal/day) and group 3+3 decreased significantly (−150 kcal/day). Conclusion Results indicate that 3+3 training may inhibit NEAT by being too time consuming and does not induce superior training adaptations to 1+1 and 2+2 training. Key words: physical activity, older adults, total energy expenditure, maximum oxygen uptake. PMID:23774582

Fatty acids in energy metabolism of the central nervous system.

PubMed

Panov, Alexander; Orynbayeva, Zulfiya; Vavilin, Valentin; Lyakhovich, Vyacheslav

2014-01-01

In this review, we analyze the current hypotheses regarding energy metabolism in the neurons and astroglia. Recently, it was shown that up to 20% of the total brain's energy is provided by mitochondrial oxidation of fatty acids. However, the existing hypotheses consider glucose, or its derivative lactate, as the only main energy substrate for the brain. Astroglia metabolically supports the neurons by providing lactate as a substrate for neuronal mitochondria. In addition, a significant amount of neuromediators, glutamate and GABA, is transported into neurons and also serves as substrates for mitochondria. Thus, neuronal mitochondria may simultaneously oxidize several substrates. Astrocytes have to replenish the pool of neuromediators by synthesis de novo, which requires large amounts of energy. In this review, we made an attempt to reconcile β-oxidation of fatty acids by astrocytic mitochondria with the existing hypothesis on regulation of aerobic glycolysis. We suggest that, under condition of neuronal excitation, both metabolic pathways may exist simultaneously. We provide experimental evidence that isolated neuronal mitochondria may oxidize palmitoyl carnitine in the presence of other mitochondrial substrates. We also suggest that variations in the brain mitochondrial metabolic phenotype may be associated with different mtDNA haplogroups.

Fatty Acids in Energy Metabolism of the Central Nervous System

PubMed Central

Orynbayeva, Zulfiya; Vavilin, Valentin; Lyakhovich, Vyacheslav

2014-01-01

In this review, we analyze the current hypotheses regarding energy metabolism in the neurons and astroglia. Recently, it was shown that up to 20% of the total brain's energy is provided by mitochondrial oxidation of fatty acids. However, the existing hypotheses consider glucose, or its derivative lactate, as the only main energy substrate for the brain. Astroglia metabolically supports the neurons by providing lactate as a substrate for neuronal mitochondria. In addition, a significant amount of neuromediators, glutamate and GABA, is transported into neurons and also serves as substrates for mitochondria. Thus, neuronal mitochondria may simultaneously oxidize several substrates. Astrocytes have to replenish the pool of neuromediators by synthesis de novo, which requires large amounts of energy. In this review, we made an attempt to reconcile β-oxidation of fatty acids by astrocytic mitochondria with the existing hypothesis on regulation of aerobic glycolysis. We suggest that, under condition of neuronal excitation, both metabolic pathways may exist simultaneously. We provide experimental evidence that isolated neuronal mitochondria may oxidize palmitoyl carnitine in the presence of other mitochondrial substrates. We also suggest that variations in the brain mitochondrial metabolic phenotype may be associated with different mtDNA haplogroups. PMID:24883315

Intrinsic aerobic capacity impacts susceptibility to acute high-fat diet-induced hepatic steatosis.

PubMed

Morris, E Matthew; Jackman, Matthew R; Johnson, Ginger C; Liu, Tzu-Wen; Lopez, Jordan L; Kearney, Monica L; Fletcher, Justin A; Meers, Grace M E; Koch, Lauren G; Britton, Stephen L; Rector, R Scott; Ibdah, Jamal A; MacLean, Paul S; Thyfault, John P

2014-08-15

Aerobic capacity/fitness significantly impacts susceptibility for fatty liver and diabetes, but the mechanisms remain unknown. Herein, we utilized rats selectively bred for high (HCR) and low (LCR) intrinsic aerobic capacity to examine the mechanisms by which aerobic capacity impacts metabolic vulnerability for fatty liver following a 3-day high-fat diet (HFD). Indirect calorimetry assessment of energy metabolism combined with radiolabeled dietary food was employed to examine systemic metabolism in combination with ex vivo measurements of hepatic lipid oxidation. The LCR, but not HCR, displayed increased hepatic lipid accumulation in response to the HFD despite both groups increasing energy intake. However, LCR rats had a greater increase in energy intake and demonstrated greater daily weight gain and percent body fat due to HFD compared with HCR. Additionally, total energy expenditure was higher in the larger LCR. However, controlling for the difference in body weight, the LCR has lower resting energy expenditure compared with HCR. Importantly, respiratory quotient was significantly higher during the HFD in the LCR compared with HCR, suggesting reduced whole body lipid utilization in the LCR. This was confirmed by the observed lower whole body dietary fatty acid oxidation in LCR compared with HCR. Furthermore, LCR liver homogenate and isolated mitochondria showed lower complete fatty acid oxidation compared with HCR. We conclude that rats bred for low intrinsic aerobic capacity show greater susceptibility for dietary-induced hepatic steatosis, which is associated with a lower energy expenditure and reduced whole body and hepatic mitochondrial lipid oxidation.

Energetic metabolism of Chromobacterium violaceum.

PubMed

Creczynski-Pasa, Tânia B; Antônio, Regina V

2004-03-31

Chromobacterium violaceum is a free-living microorganism, normally exposed to diverse environmental conditions; it has a versatile energy-generating metabolism. This bacterium is capable of exploiting a wide range of energy resources by using appropriate oxidases and reductases. This allows C. violaceum to live in both aerobic and anaerobic conditions. In aerobic conditions, C. violaceum is able to grow in a minimal medium with simple sugars, such as glucose, fructose, galactose, and ribose; both Embden-Meyerhoff, tricarboxylic acid and glyoxylate cycles are used. The respiratory chain supplies energy, as well as substrates for other metabolic pathways. Under anaerobic conditions, C. violaceum metabolizes glucose, producing acetic and formic acid, but not lactic acid or ethanol. C. violaceum is also able to use amino acids and lipids as an energy supply.

MYC-induced cancer cell energy metabolism and therapeutic opportunities.

PubMed

Dang, Chi V; Le, Anne; Gao, Ping

2009-11-01

Although cancers have altered glucose metabolism, termed the Warburg effect, which describes the increased uptake and conversion of glucose to lactate by cancer cells under adequate oxygen tension, changes in the metabolism of glutamine and fatty acid have also been documented. The MYC oncogene, which contributes to the genesis of many human cancers, encodes a transcription factor c-Myc, which links altered cellular metabolism to tumorigenesis. c-Myc regulates genes involved in the biogenesis of ribosomes and mitochondria, and regulation of glucose and glutamine metabolism. With E2F1, c-Myc induces genes involved in nucleotide metabolism and DNA replication, and microRNAs that homeostatically attenuate E2F1 expression. With the hypoxia inducible transcription factor HIF-1, ectopic c-Myc cooperatively induces a transcriptional program for hypoxic adaptation. Myc regulates gene expression either directly, such as glycolytic genes including lactate dehydrogenase A (LDHA), or indirectly, such as repression of microRNAs miR-23a/b to increase glutaminase (GLS) protein expression and glutamine metabolism. Ectopic MYC expression in cancers, therefore, could concurrently drive aerobic glycolysis and/or oxidative phosphorylation to provide sufficient energy and anabolic substrates for cell growth and proliferation in the context of the tumor microenvironment. Collectively, these studies indicate that Myc-mediated altered cancer cell energy metabolism could be translated for the development of new anticancer therapies.

Effect of Combined Exercise Versus Aerobic-Only Training on Skeletal Muscle Lipid Metabolism in a Rodent Model of Type1 Diabetes.

PubMed

Dotzert, Michelle S; McDonald, Matthew W; Murray, Michael R; Nickels, J Zachary; Noble, Earl G; Melling, C W James

2017-12-04

Abnormal skeletal muscle lipid metabolism is associated with insulin resistance in people with type 1 diabetes. Although lipid metabolism is restored with aerobic exercise training, the risk for postexercise hypoglycemia is increased with this modality. Integrating resistance and aerobic exercise is associated with reduced hypoglycemic risk; however, the effects of this exercise modality on lipid metabolism and insulin resistance remain unknown. We compared the effects of combined (aerobic + resistance) versus aerobic exercise training on oxidative capacity and muscle lipid metabolism in a rat model of type 1 diabetes. Male Sprague-Dawley rats were divided into 4 groups: sedentary control (C), sedentary control + diabetes (CD), diabetes + high-intensity aerobic exercise (DAE) and diabetes + combined aerobic and resistance exercise (DARE). Following diabetes induction (20 mg/kg streptozotocin over five days), DAE rats ran for 12 weeks (5 days/week for 1 hour) on a motorized treadmill (27 m/min at a 6-degree grade), and DARE rats alternated daily between running and incremental weighted ladder climbing. After training, DAE showed reduced muscle CD36 protein content and lipid content compared to CD (p≤0.05). DAE rats also had significantly increased citrate synthase (CS) activity compared to CD (p≤0.05). DARE rats showed reduced CD36 protein content compared to CD and increased CS activity compared to CD and DAE rats (p≤0.05). DARE rats demonstrated increased skeletal muscle lipid staining, elevated lipin-1 protein content and insulin sensitivity (p≤0.05). Integration of aerobic and resistance exercise may exert a synergistic effect, producing adaptations characteristic of the "athlete's paradox," including increased capacity to store and oxidize lipids. Crown Copyright © 2017. Published by Elsevier Inc. All rights reserved.

Aerobic fitness and metabolic health in children: A clinical validation of directly measured maximal oxygen consumption versus performance measures as markers of health.

PubMed

Aadland, Eivind; Kvalheim, Olav Martin; Rajalahti, Tarja; Skrede, Turid; Resaland, Geir Kåre

2017-09-01

High aerobic fitness is consistently associated with a favorable metabolic health profile in children. However, measurement of oxygen uptake, regarded as the gold standard for evaluating aerobic fitness, is often not feasible. Thus, the aim of the present study was to perform a clinical validation of three measures of aerobic fitness (peak oxygen consumption [VO 2peak ] and time to exhaustion [TTE] determined from a graded treadmill protocol to exhaustion, and the Andersen intermittent running test) with clustered metabolic health in 10-year-old children. We included 93 children (55 boys and 38 girls) from Norway during 2012-2013 in the study. Associations between aerobic fitness and three different composite metabolic health scores (including lipoprotein subgroup particle concentrations, triglyceride, glucose, systolic blood pressure, and waist-to-height ratio) were determined by regression analyses adjusting for sex. The relationships among the measures of aerobic fitness were r  = 0.78 for VO 2peak vs. TTE, r  = 0.63 for VO 2peak vs. the Andersen test, and r  = 0.67 for TTE vs. the Andersen test. The Andersen test showed the strongest associations across all markers of metabolic health ( r  = - 0.45 to - 0.31, p  < 0.002), followed by VO 2peak ( r  = - 0.35 to - 0.12, p  < 0.256), and TTE ( r  = - 0.28 to - 0.10, p  < 0.334). Our findings indicate that indirect measures of aerobic fitness do not stand back as markers of metabolic health status in children, compared to VO 2peak . This is of great importance as good field tests provide opportunities for measuring aerobic fitness in many settings where measuring VO 2peak are impossible.

Aerobic vs. resistance exercise in non-alcoholic fatty liver disease: A systematic review.

PubMed

Hashida, Ryuki; Kawaguchi, Takumi; Bekki, Masafumi; Omoto, Masayuki; Matsuse, Hiroo; Nago, Takeshi; Takano, Yoshio; Ueno, Takato; Koga, Hironori; George, Jacob; Shiba, Naoto; Torimura, Takuji

2017-01-01

Exercise is a first-line therapy for patients with non-alcoholic fatty liver disease (NAFLD). We sought to: 1) summarize effective aerobic and resistance exercise protocols for NAFLD; and 2) compare the effects and energy consumption of aerobic and resistance exercises. A literature search was performed using PubMed, Web of Science, and Scopas to January 28, 2016. From a total of 95 articles, 23 studies including 24 aerobic and 7 resistance exercise protocols were selected for the summary of exercise protocols. Twelve articles including 13 aerobic and 4 resistance exercise protocols were selected for the comparative analysis. For aerobic exercise, the median effective protocol was 4.8 metabolic equivalents (METs) for 40min/session, 3times/week for 12weeks. For resistance exercise, the median effective protocol was 3.5 METs for 45min/session, 3times/week for 12weeks. Aerobic and resistance exercise improved hepatic steatosis. No significant difference was seen in the duration, frequency, or period of exercise between the two exercise groups; however, %VO 2 max and energy consumption were significantly lower in the resistance than in the aerobic group (50% [45-98] vs. 28% [28-28], p=0.0034; 11,064 [6394-21,087] vs. 6470 [4104-12,310] kcal/total period, p=0.0475). Resistance exercise improves NAFLD with less energy consumption. Thus, resistance exercise may be more feasible than aerobic exercise for NAFLD patients with poor cardiorespiratory fitness or for those who cannot tolerate or participate in aerobic exercise. These data may indicate a possible link between resistance exercise and lipid metabolism in the liver. Both aerobic and resistance exercise reduce hepatic steatosis in non-alcoholic fatty liver disease (NAFLD) with similar frequency, duration, and period of exercise (40-45min/session 3times/week for 12weeks); however, the two forms of exercise have different characteristics. Intensity and energy consumption were significantly lower for resistance than for

Aerobic and Strength Training in Concomitant Metabolic Syndrome and Type 2 Diabetes

PubMed Central

Earnest, Conrad P.; Johannsen, Neil M.; Swift, Damon L.; Gillison, Fiona B.; Mikus, Catherine R.; Lucia, Alejandro; Kramer, Kimberly; Lavie, Carl J.; Church, Timothy S.

2014-01-01

Purpose Concomitant type 2 diabetes (T2D) and metabolic syndrome exacerbates mortality risk; yet, few studies have examined the effect of combining (AER+RES) aerobic (AER) and resistance (RES) training for individuals with T2D and metabolic syndrome. Methods We examined AER, RES, and AER+RES training (9-months) commensurate with physical activity guidelines in individuals with T2D (N=262, 63% female, 44% black). Primary outcomes were change in, and prevalence of, metabolic syndrome score at follow-up (mean, 95%CI). Secondary outcomes included maximal cardiorespiratory fitness (VO2peak and estimated METs from time-to-exhaustion (TTE), and exercise efficiency calculated as the slope of the line between ventilatory threshold, respiratory compensation, and maximal fitness. General linear models and bootstrapped Spearman correlations were used to examine changes in metabolic syndrome associated with training primary and secondary outcome variables. Results We observed a significant decrease in metabolic syndrome scores (P-for-trend, 0.003) for AER (−0.59, 95%CI, −1.00, −0.21) and AER+RES (−0.79, 95%CI, −1.40, −0.35), both being significant (P < 0.02) vs. Control (0.26, 95%CI, −0.58, 0.40) and RES (−0.13, 95%CI, −1.00, 0.24). This lead to a reduction in metabolic syndrome prevalence for the AER (56% vs. 43%) and AER+RES (55% vs. 46%) groups between baseline and follow-up. The observed decrease in metabolic syndrome was mediated by significant improvements in exercise efficiency for the AER and AER+RES training groups (P<0.05), which was more strongly related to TTE (25–30%; r= −0.38; 95% CI: −0.55, −0.19) than VO2peak (5–6%; r= −0.24; 95% CI: −0.45, −0.01). Conclusion Aerobic and AER+RES training significantly improves metabolic syndrome scores and prevalence in patients with T2D. These improvements appear to be associated with improved exercise efficiency and are more strongly related to improved TTE versus VO2peak. PMID:24389523

Effects of aerobic exercise training on serum sex hormone binding globulin, body fat index, and metabolic syndrome factors in obese postmenopausal women.

PubMed

Kim, Jong-Won; Kim, Do-Yeon

2012-12-01

The percentage of obese postmenopausal women with metabolic syndrome is rising, and physical factors associated with the metabolic syndrome prevalence or incidence are also rising, including high body mass index (BMI), visceral fat area (VFA), low plasma sex hormone-binding globulin (SHBG) levels, and low cardiorespiratory fitness. Therefore, we investigated the influence of aerobic exercise on SHBG, body fat index (BFI), and metabolic syndrome factors in obese postmenopausal Korean women. Thirty healthy postmenopausal, women aged 53.46 ± 2.4 years and with over 32% body fat, were randomly assigned to an aerobic exercise group (EX; n=15) or to a "nonexercise" control (Con; n=15) group. The primary outcome measurements were serum SHBG, lipid profiles, insulin levels, and metabolic syndrome factors. Secondary outcome measurements were body composition, VFA, blood pressure (BP), and homeostasis model assessment of insulin resistance (HOMA-IR). Posttraining body weight and BFI (P<0.05), total cholesterol, glucose, and insulin levels (P<0.01), BP, and HOMA-IR (P<0.001) decreased, whereas SHBG (P<0.001) and metabolic syndrome factors (P<0.01) improved in the exercise group but not in the control group. SHBG levels also showed a significant positive correlation with high-density lipoprotein cholesterol (HDL-C) and significant negative correlations withglucose, diastolic blood pressure, fat mass, BMI, and percent body fat (P<0.05). Our findings indicate that aerobic exercise improves body composition, SHBG, insulin levels, and metabolic syndrome factors. These findings suggest that in obesepostmenopausal Korean women, 16 weeks of aerobic exercise is effective for preventing the metabolic syndrome caused by obesity.

Aerobic exercise training reduces arterial stiffness in metabolic syndrome

PubMed Central

Donley, David A.; Fournier, Sara B.; Reger, Brian L.; DeVallance, Evan; Bonner, Daniel E.; Olfert, I. Mark; Frisbee, Jefferson C.

2014-01-01

The metabolic syndrome (MetS) is associated with a threefold increase risk of cardiovascular disease (CVD) mortality partly due to increased arterial stiffening. We compared the effects of aerobic exercise training on arterial stiffening/mechanics in MetS subjects without overt CVD or type 2 diabetes. MetS and healthy control (Con) subjects underwent 8 wk of exercise training (ExT; 11 MetS and 11 Con) or remained inactive (11 MetS and 10 Con). The following measures were performed pre- and postintervention: radial pulse wave analysis (applanation tonometry) was used to measure augmentation pressure and index, central pressures, and an estimate of myocardial efficiency; arterial stiffness was assessed from carotid-femoral pulse-wave velocity (cfPWV, applanation tonometry); carotid thickness was assessed from B-mode ultrasound; and peak aerobic capacity (gas exchange) was performed in the seated position. Plasma matrix metalloproteinases (MMP) and CVD risk (Framingham risk score) were also assessed. cfPWV was reduced (P < 0.05) in MetS-ExT subjects (7.9 ± 0.6 to 7.2 ± 0.4 m/s) and Con-ExT (6.6 ± 1.8 to 5.6 ± 1.6 m/s). Exercise training reduced (P < 0.05) central systolic pressure (116 ± 5 to 110 ± 4 mmHg), augmentation pressure (9 ± 1 to 7 ± 1 mmHg), augmentation index (19 ± 3 to 15 ± 4%), and improved myocardial efficiency (155 ± 8 to 168 ± 9), but only in the MetS group. Aerobic capacity increased (P < 0.05) in MetS-ExT (16.6 ± 1.0 to 19.9 ± 1.0) and Con-ExT subjects (23.8 ± 1.6 to 26.3 ± 1.6). MMP-1 and -7 were correlated with cfPWV, and both MMP-1 and -7 were reduced post-ExT in MetS subjects. These findings suggest that some of the pathophysiological changes associated with MetS can be improved after aerobic exercise training, thereby lowering their cardiovascular risk. PMID:24744384

Beneficial mechanisms of aerobic exercise on hepatic lipid metabolism in non-alcoholic fatty liver disease.

PubMed

Guo, Rui; Liong, Emily C; So, Kwok Fai; Fung, Man-Lung; Tipoe, George L

2015-04-01

Non-alcoholic fatty liver disease (NAFLD) refers to any fatty liver disease that is not due to excessive use of alcohol. NAFLD probably results from abnormal hepatic lipid metabolism and insulin resistance. Aerobic exercise is shown to improve NAFLD. This review aimed to evaluate the molecular mechanisms involved in the beneficial effects of aerobic exercise on NAFLD. We searched articles in English on the role of aerobic exercise in NAFLD therapy in PubMed. The mechanisms of chronic aerobic exercise in regulating the outcome of NAFLD include: (i) reducing intrahepatic fat content by down-regulating sterol regulatory element-binding protein-1c and up-regulating peroxisome proliferator-activated receptor gamma expression levels; (ii) decreasing hepatic oxidative stress through modulating the reactive oxygen species, and enhancing antioxidant enzymes such as catalase and glutathione peroxidase; (iii) ameliorating hepatic inflammation via the inhibition of pro-inflammatory mediators such as tumor necrosis factor-alpha and interleukin-1 beta; (iv) attenuating mitochondrial dependent apoptosis by reducing cytochrome C released from the mitochondria to the cytosol; and (v) inducing hepato-protective autophagy. Aerobic exercise, via different mechanisms, significantly decreases the fat content of the liver and improves the outcomes of patients with NAFLD.

Effects of aerobic exercise on the resting heart rate, physical fitness, and arterial stiffness of female patients with metabolic syndrome.

PubMed

Kang, Seol-Jung; Kim, Eon-Ho; Ko, Kwang-Jun

2016-06-01

[Purpose] The purpose of this study was to investigate the effects of aerobic exercise on the resting heart rate, physical fitness, and arterial stiffness or female patients with metabolic syndrome. [Subjects and Methods] Subjects were randomly assigned to an exercise group (n=12) or a control group (n=11). Subjects in the exercise group performed aerobic exercise at 60-80% of maximum heart rate for 40 min 5 times a week for 12 weeks. The changes in metabolic syndrome risk factors, resting heart rate, physical fitness, and arterial stiffness were measured and analyzed before and after initiation of the exercise program to determine the effect of exercise. Arterial stiffness was assessed based on brachial-ankle pulse wave velocity (ba-PWV). [Results] Compared to the control group; The metabolic syndrome risk factors (weight, % body fat, waist circumference, systolic blood pressure, diastolic blood pressure, and HDL-Cholesterol) were significantly improved in the exercise: resting heart rate was significantly decreased; VO2max, muscle strength and muscle endurance were significantly increased; and ba-PWV was significantly decreased. [Conclusion] Aerobic exercise had beneficial effects on the resting heart rate, physical fitness, and arterial stiffness of patients with metabolic syndrome.

Aerobic Degradation of Trichloroethylene by Co-Metabolism Using Phenol and Gasoline as Growth Substrates

PubMed Central

Li, Yan; Li, Bing; Wang, Cui-Ping; Fan, Jun-Zhao; Sun, Hong-Wen

2014-01-01

Trichloroethylene (TCE) is a common groundwater contaminant of toxic and carcinogenic concern. Aerobic co-metabolic processes are the predominant pathways for TCE complete degradation. In this study, Pseudomonas fluorescens was studied as the active microorganism to degrade TCE under aerobic condition by co-metabolic degradation using phenol and gasoline as growth substrates. Operating conditions influencing TCE degradation efficiency were optimized. TCE co-metabolic degradation rate reached the maximum of 80% under the optimized conditions of degradation time of 3 days, initial OD600 of microorganism culture of 0.14 (1.26 × 107 cell/mL), initial phenol concentration of 100 mg/L, initial TCE concentration of 0.1 mg/L, pH of 6.0, and salinity of 0.1%. The modified transformation capacity and transformation yield were 20 μg (TCE)/mg (biomass) and 5.1 μg (TCE)/mg (phenol), respectively. Addition of nutrient broth promoted TCE degradation with phenol as growth substrate. It was revealed that catechol 1,2-dioxygenase played an important role in TCE co-metabolism. The dechlorination of TCE was complete, and less chlorinated products were not detected at the end of the experiment. TCE could also be co-metabolized in the presence of gasoline; however, the degradation rate was not high (28%). When phenol was introduced into the system of TCE and gasoline, TCE and gasoline could be removed at substantial rates (up to 59% and 69%, respectively). This study provides a promising approach for the removal of combined pollution of TCE and gasoline. PMID:24857922

Aerobic degradation of trichloroethylene by co-metabolism using phenol and gasoline as growth substrates.

PubMed

Li, Yan; Li, Bing; Wang, Cui-Ping; Fan, Jun-Zhao; Sun, Hong-Wen

2014-05-22

Trichloroethylene (TCE) is a common groundwater contaminant of toxic and carcinogenic concern. Aerobic co-metabolic processes are the predominant pathways for TCE complete degradation. In this study, Pseudomonas fluorescens was studied as the active microorganism to degrade TCE under aerobic condition by co-metabolic degradation using phenol and gasoline as growth substrates. Operating conditions influencing TCE degradation efficiency were optimized. TCE co-metabolic degradation rate reached the maximum of 80% under the optimized conditions of degradation time of 3 days, initial OD600 of microorganism culture of 0.14 (1.26×10⁷ cell/mL), initial phenol concentration of 100 mg/L, initial TCE concentration of 0.1 mg/L, pH of 6.0, and salinity of 0.1%. The modified transformation capacity and transformation yield were 20 μg (TCE)/mg (biomass) and 5.1 μg (TCE)/mg (phenol), respectively. Addition of nutrient broth promoted TCE degradation with phenol as growth substrate. It was revealed that catechol 1,2-dioxygenase played an important role in TCE co-metabolism. The dechlorination of TCE was complete, and less chlorinated products were not detected at the end of the experiment. TCE could also be co-metabolized in the presence of gasoline; however, the degradation rate was not high (28%). When phenol was introduced into the system of TCE and gasoline, TCE and gasoline could be removed at substantial rates (up to 59% and 69%, respectively). This study provides a promising approach for the removal of combined pollution of TCE and gasoline.

Astrocyte glycogen and brain energy metabolism.

PubMed

Brown, Angus M; Ransom, Bruce R

2007-09-01

The brain contains glycogen but at low concentration compared with liver and muscle. In the adult brain, glycogen is found predominantly in astrocytes. Astrocyte glycogen content is modulated by a number of factors including some neurotransmitters and ambient glucose concentration. Compelling evidence indicates that astrocyte glycogen breaks down during hypoglycemia to lactate that is transferred to adjacent neurons or axons where it is used aerobically as fuel. In the case of CNS white matter, this source of energy can extend axon function for 20 min or longer. Likewise, during periods of intense neural activity when energy demand exceeds glucose supply, astrocyte glycogen is degraded to lactate, a portion of which is transferred to axons for fuel. Astrocyte glycogen, therefore, offers some protection against hypoglycemic neural injury and ensures that neurons and axons can maintain their function during very intense periods of activation. These emerging principles about the roles of astrocyte glycogen contradict the long held belief that this metabolic pool has little or no functional significance.

Sustained exercise-trained juvenile black carp (Mylopharyngodon piceus) at a moderate water velocity exhibit improved aerobic swimming performance and increased postprandial metabolic responses

PubMed Central

Li, Xiuming; Zhang, Yaoguang; Li, Xiaojin; Zheng, Hua; Peng, Jianglan

2018-01-01

ABSTRACT The objectives of this study were to examine whether sustained exercise training at four water velocities, i.e. nearly still water (control), 1 body length (BL) s−1, 2 BL s−1 and 4 BL s−1, has effects on swimming performance and digestive metabolism in juvenile black carp (Mylopharyngodon piceus). The results demonstrated that fish subjected to sustained training at 2 and 4 BL s−1 showed significantly higher critical swimming speed (Ucrit) and maximum metabolic rate (MMR) over the control group. Fish subjected to sustained training at 1 and 2 BL s−1 showed a significantly (30 and 54%) prolonged duration, 14 and 17% higher postprandial ṀO2 increment (i.e. ṀO2peak), and 62 and 92% more energy expended on specific dynamic action (SDA), respectively, after consuming a similar meal over fish kept in nearly still water. These results suggest that (1) sustained exercise training at a higher speed (2 or 4 BL s−1) had a positive influence on the aerobic swimming performance of juvenile M. piceus, which may be associated with improved aerobic metabolism; and (2) sustained exercise training at a lower speed (1 or 2 BL s−1) resulted in elevated postprandial metabolic responses in juvenile M. piceus. PMID:29463516

Elucidating the role of copper in CHO cell energy metabolism using (13)C metabolic flux analysis.

PubMed

Nargund, Shilpa; Qiu, Jinshu; Goudar, Chetan T

2015-01-01

(13)C-metabolic flux analysis was used to understand copper deficiency-related restructuring of energy metabolism, which leads to excessive lactate production in recombinant protein-producing CHO cells. Stationary-phase labeling experiments with U-(13)C glucose were conducted on CHO cells grown under high and limiting copper in 3 L fed-batch bioreactors. The resultant labeling patterns of soluble metabolites were measured by GC-MS and used to estimate metabolic fluxes in the central carbon metabolism pathways using OpenFlux. Fluxes were evaluated 300 times from stoichiometrically feasible random guess values and their confidence intervals calculated by Monte Carlo simulations. Results from metabolic flux analysis exhibited significant carbon redistribution throughout the metabolic network in cells under Cu deficiency. Specifically, glycolytic fluxes increased (25%-79% relative to glucose uptake) whereas fluxes through the TCA and pentose phosphate pathway (PPP) were lower (15%-23% and 74%, respectively) compared with the Cu-containing condition. Furthermore, under Cu deficiency, 33% of the flux entering TCA via the pyruvate node was redirected to lactate and malate production. Based on these results, we hypothesize that Cu deficiency disrupts the electron transport chain causing ATP deficiency, redox imbalance, and oxidative stress, which in turn drive copper-deficient CHO cells to produce energy via aerobic glycolysis, which is associated with excessive lactate production, rather than the more efficient route of oxidative phosphorylation. © 2015 American Institute of Chemical Engineers.

Metabolic myopathies

NASA Technical Reports Server (NTRS)

Martin, A.; Haller, R. G.; Barohn, R.; Blomqvist, C. G. (Principal Investigator)

1994-01-01

Metabolic myopathies are disorders of muscle energy production that result in skeletal muscle dysfunction. Cardiac and systemic metabolic dysfunction may coexist. Symptoms are often intermittent and provoked by exercise or changes in supply of lipid and carbohydrate fuels. Specific disorders of lipid and carbohydrate metabolism in muscle are reviewed. Evaluation often requires provocative exercise testing. These tests may include ischemic forearm exercise, aerobic cycle exercise, and 31P magnetic resonance spectroscopy with exercise.

Association of Resistance Exercise, Independent of and Combined With Aerobic Exercise, With the Incidence of Metabolic Syndrome.

PubMed

Bakker, Esmée A; Lee, Duck-Chul; Sui, Xuemei; Artero, Enrique G; Ruiz, Jonatan R; Eijsvogels, Thijs M H; Lavie, Carl J; Blair, Steven N

2017-08-01

To determine the association of resistance exercise, independent of and combined with aerobic exercise, with the risk of development of metabolic syndrome (MetS). The study cohort included adults (mean ± SD age, 46±9.5 years) who received comprehensive medical examinations at the Cooper Clinic in Dallas, Texas, between January 1, 1987, and December, 31, 2006. Exercise was assessed by self-reported frequency and minutes per week of resistance and aerobic exercise and meeting the US Physical Activity Guidelines (resistance exercise ≥2 d/wk; aerobic exercise ≥500 metabolic equivalent min/wk) at baseline. The incidence of MetS was based on the National Cholesterol Education Program Adult Treatment Panel III criteria. We used Cox regression to generate hazard ratios (HRs) and 95% CIs. Among 7418 participants, 1147 (15%) had development of MetS during a median follow-up of 4 years (maximum, 19 years; minimum, 0.1 year). Meeting the resistance exercise guidelines was associated with a 17% lower risk of MetS (HR, 0.83; 95% CI, 0.73-0.96; P=.009) after adjusting for potential confounders and aerobic exercise. Further, less than 1 hour of weekly resistance exercise was associated with 29% lower risk of development of MetS (HR, 0.71; 95% CI, 0.56-0.89; P=.003) compared with no resistance exercise. However, larger amounts of resistance exercise did not provide further benefits. Individuals meeting both recommended resistance and aerobic exercise guidelines had a 25% lower risk of development of MetS (HR, 0.75; 95% CI, 0.63-0.89; P<.001) compared with meeting neither guideline. Participating in resistance exercise, even less than 1 hour per week, was associated with a lower risk of development of MetS, independent of aerobic exercise. Health professionals should recommend that patients perform resistance exercise along with aerobic exercise to reduce MetS. Copyright © 2017 Mayo Foundation for Medical Education and Research. Published by Elsevier Inc. All rights reserved.

The effect of aerobic exercise training on growth performance, digestive enzyme activities and postprandial metabolic response in juvenile qingbo (Spinibarbus sinensis).

PubMed

Li, Xiu-Ming; Yu, Li-Juan; Wang, Chuan; Zeng, Ling-Qing; Cao, Zhen-Dong; Fu, Shi-Jian; Zhang, Yao-Guang

2013-09-01

Continual swimming exercise usually promotes growth in fish at a moderate water velocity. We hypothesized that the improvement in growth in exercise-trained fish may be accompanied by increases in digestive enzyme activity, respiratory capacity and, hence, postprandial metabolism. Juvenile qingbo fish (Spinibarbus sinensis) were subjected to aerobic training for 8weeks at a water velocity of control (3cms(-1)), 1, 2 and 4 body length (bl)s(-1) at a constant temperature of 25°C. The feed intake (FI), food conversion rate (FCR), specific growth rate (SGR), whole-body composition, trypsin and lipase activities, maximal oxygen consumption (M˙O2max) and postprandial M˙O2 response were measured at the end of the training period. Aerobic exercise training induced a significant increase in FI compared with the control group, while the FCR of the 4bls(-1) group was significantly lower than for the other three groups (P<0.05). The 1 and 2bls(-1) groups showed a significantly higher SGR over the control group (P<0.05). The whole-body fat and protein contents were significantly altered after aerobic exercise training (P<0.05). Furthermore, aerobic exercise training elevated the activity of both trypsin and lipase in the hepatopancreas and intestinal tract of juvenile S. sinensis. The M˙O2max of the 4bls(-1) training group was significantly higher than for the control group. The resting M˙O2 (M˙O2rest) and peak postprandial M˙O2 (M˙O2peak) in the three training groups were significantly higher than in the control group (P<0.05). Time to M˙O2peak was significantly shorter in the 1, 2 and 4bls(-1) training groups compared with the control group, while exercise training showed no effect on SDA (specific dynamic action) duration, factorial metabolic scope, energy expended on SDA and the SDA coefficient when compared to the control group. These data suggest that (1) the optimum water velocity for the growth of juvenile S. sinensis occurred at approximately 2.4bls(-1); (2

Is Maximum Food Intake in Endotherms Constrained by Net or Factorial Aerobic Scope? Lessons from the Leaf-Eared Mouse.

PubMed

Maldonado, Karin; Sabat, Pablo; Piriz, Gabriela; Bogdanovich, José M; Nespolo, Roberto F; Bozinovic, Francisco

2016-01-01

Food availability varies substantially throughout animals' lifespans, thus the ability to profit from high food levels may directly influence animal fitness. Studies exploring the link between basal metabolic rate (BMR), growth, reproduction, and other fitness traits have shown varying relationships in terms of both magnitude and direction. The diversity of results has led to the hypothesis that these relationships are modulated by environmental conditions (e.g., food availability), suggesting that the fitness consequences of a given BMR may be context-dependent. In turn, there is indirect evidence that individuals with an increased capacity for aerobic work also have a high capacity for acquiring energy from food. Surprisingly, very few studies have explored the correlation between maximum rates of energy acquisition and BMR in endotherms, and to the best of our knowledge, none have attempted to elucidate relationships between the former and aerobic capacity [e.g., maximum metabolic rate (MMR), aerobic scope (Factorial aerobic scope, FAS; Net aerobic scope, NAS)]. In this study, we measured BMR, MMR, maximum food intake (recorded under low ambient temperature and ad libitum food conditions; MFI), and estimated aerobic scope in the leaf-eared mouse ( Phyllotis darwini ). We, then, examined correlations among these variables to determine whether metabolic rates and aerobic scope are functionally correlated, and whether an increased aerobic capacity is related to a higher MFI. We found that aerobic capacity measured as NAS is positively correlated with MFI in endotherms, but with neither FAS nor BMR. Therefore, it appears plausible that the capacity for assimilating energy under conditions of abundant resources is determined adaptively by NAS, as animals with higher NAS would be promoted by selection. In theory, FAS is an invariant measurement of the extreme capacity for energy turnover in relation to resting expenditure, whereas NAS represents the maximum capacity

Adaptive remodeling of skeletal muscle energy metabolism in high-altitude hypoxia: Lessons from AltitudeOmics.

PubMed

Chicco, Adam J; Le, Catherine H; Gnaiger, Erich; Dreyer, Hans C; Muyskens, Jonathan B; D'Alessandro, Angelo; Nemkov, Travis; Hocker, Austin D; Prenni, Jessica E; Wolfe, Lisa M; Sindt, Nathan M; Lovering, Andrew T; Subudhi, Andrew W; Roach, Robert C

2018-05-04

Metabolic responses to hypoxia play important roles in cell survival strategies and disease pathogenesis in humans. However, the homeostatic adjustments that balance changes in energy supply and demand to maintain organismal function under chronic low oxygen conditions remain incompletely understood, making it difficult to distinguish adaptive from maladaptive responses in hypoxia-related pathologies. We integrated metabolomic and proteomic profiling with mitochondrial respirometry and blood gas analyses to comprehensively define the physiological responses of skeletal muscle energy metabolism to 16 days of high-altitude hypoxia (5260 m) in healthy volunteers from the AltitudeOmics project. In contrast to the view that hypoxia down-regulates aerobic metabolism, results show that mitochondria play a central role in muscle hypoxia adaptation by supporting higher resting phosphorylation potential and enhancing the efficiency of long-chain acylcarnitine oxidation. This directs increases in muscle glucose toward pentose phosphate and one-carbon metabolism pathways that support cytosolic redox balance and help mitigate the effects of increased protein and purine nucleotide catabolism in hypoxia. Muscle accumulation of free amino acids favor these adjustments by coordinating cytosolic and mitochondrial pathways to rid the cell of excess nitrogen, but might ultimately limit muscle oxidative capacity in vivo Collectively, these studies illustrate how an integration of aerobic and anaerobic metabolism is required for physiological hypoxia adaptation in skeletal muscle, and highlight protein catabolism and allosteric regulation as unexpected orchestrators of metabolic remodeling in this context. These findings have important implications for the management of hypoxia-related diseases and other conditions associated with chronic catabolic stress. © 2018 by The American Society for Biochemistry and Molecular Biology, Inc.

Aerobic exercise training reduces arterial stiffness in metabolic syndrome.

PubMed

Donley, David A; Fournier, Sara B; Reger, Brian L; DeVallance, Evan; Bonner, Daniel E; Olfert, I Mark; Frisbee, Jefferson C; Chantler, Paul D

2014-06-01

The metabolic syndrome (MetS) is associated with a threefold increase risk of cardiovascular disease (CVD) mortality partly due to increased arterial stiffening. We compared the effects of aerobic exercise training on arterial stiffening/mechanics in MetS subjects without overt CVD or type 2 diabetes. MetS and healthy control (Con) subjects underwent 8 wk of exercise training (ExT; 11 MetS and 11 Con) or remained inactive (11 MetS and 10 Con). The following measures were performed pre- and postintervention: radial pulse wave analysis (applanation tonometry) was used to measure augmentation pressure and index, central pressures, and an estimate of myocardial efficiency; arterial stiffness was assessed from carotid-femoral pulse-wave velocity (cfPWV, applanation tonometry); carotid thickness was assessed from B-mode ultrasound; and peak aerobic capacity (gas exchange) was performed in the seated position. Plasma matrix metalloproteinases (MMP) and CVD risk (Framingham risk score) were also assessed. cfPWV was reduced (P < 0.05) in MetS-ExT subjects (7.9 ± 0.6 to 7.2 ± 0.4 m/s) and Con-ExT (6.6 ± 1.8 to 5.6 ± 1.6 m/s). Exercise training reduced (P < 0.05) central systolic pressure (116 ± 5 to 110 ± 4 mmHg), augmentation pressure (9 ± 1 to 7 ± 1 mmHg), augmentation index (19 ± 3 to 15 ± 4%), and improved myocardial efficiency (155 ± 8 to 168 ± 9), but only in the MetS group. Aerobic capacity increased (P < 0.05) in MetS-ExT (16.6 ± 1.0 to 19.9 ± 1.0) and Con-ExT subjects (23.8 ± 1.6 to 26.3 ± 1.6). MMP-1 and -7 were correlated with cfPWV, and both MMP-1 and -7 were reduced post-ExT in MetS subjects. These findings suggest that some of the pathophysiological changes associated with MetS can be improved after aerobic exercise training, thereby lowering their cardiovascular risk. Copyright © 2014 the American Physiological Society.

Aerobic microbial mineralization of dichloroethene as sole carbon substrate

USGS Publications Warehouse

Bradley, P.M.; Chapelle, F.H.

2000-01-01

Microorganisms indigenous to the bed sediments of a black- water stream utilized 1,2-dichloroethene (1,2-DCE) as a sole carbon substrate for aerobic metabolism. Although no evidence of growth was observed in the minimal salts culture media used in this study, efficient aerobic microbial mineralization of 1,2-DCE as sole carbon substrate was maintained through three sequential transfers (107 final dilution) of the original environmental innoculum. These results indicate that 1,2-DCE can be utilized as a primary substrate to support microbial metabolism under aerobic conditions.Microorganisms indigenous to the bed sediments of a black-water stream utilized 1,2-dichloroethene (1,2-DCE) as a sole carbon substrate for aerobic metabolism. Although no evidence of growth was observed in the minimal salts culture media used in this study, efficient aerobic microbial mineralization of 1,2-DCE as sole carbon substrate was maintained through three sequential transfers (107 final dilution) of the original environmental innoculum. These results indicate that 1,2-DCE can be utilized as a primary substrate to support microbial metabolism under aerobic conditions.

Energy transfer in “parasitic” cancer metabolism

PubMed Central

Martinez-Outschoorn, Ubaldo E; Pestell, Richard G; Howell, Anthony; Tykocinski, Mark L; Nagajyothi, Fnu; Machado, Fabiana S; Tanowitz, Herbert B

2011-01-01

It is now widely recognized that the tumor microenvironment promotes cancer cell growth and metastasis via changes in cytokine secretion and extra-cellular matrix remodeling. However, the role of tumor stromal cells in providing energy for epithelial cancer cell growth is a newly emerging paradigm. For example, we and others have recently proposed that tumor growth and metastasis is related to an energy imbalance. Host cells produce energy-rich nutrients via catabolism (through autophagy, mitophagy and aerobic glycolysis), which are then transferred to cancer cells, to fuel anabolic tumor growth. Stromal cell derived L-lactate is taken up by cancer cells and is used for mitochondrial oxidative phosphorylation (OXPHOS), to produce ATP efficiently. However, “parasitic” energy transfer may be a more generalized mechanism in cancer biology than previously appreciated. Two recent papers in Science and Nature Medicine now show that lipolysis in host tissues also fuels tumor growth. These studies demonstrate that free fatty acids produced by host cell lipolysis are re-used via β-oxidation (β-OX) in cancer cell mitochondria. Thus, stromal catabolites (such as lactate, ketones, glutamine and free fatty acids) promote tumor growth by acting as high-energy onco-metabolites. As such, host catabolism via autophagy, mitophagy and lipolysis may explain the pathogenesis of cancer-associated cachexia and provides exciting new druggable targets for novel therapeutic interventions. Taken together, these findings also suggest that tumor cells promote their own growth and survival by behaving as a “parasitic organism.” Hence, we propose the term “parasitic cancer metabolism” to describe this type of metabolic-coupling in tumors. Targeting tumor cell mitochondria (OXPHOS and β-OX) would effectively uncouple tumor cells from their hosts, leading to their acute starvation. In this context, we discuss new evidence that high-energy onco-metabolites (produced by the stroma

Effects of aerobic exercise and dietary carbohydrate on energy expenditure and body composition during weight reduction in obese women.

PubMed

Racette, S B; Schoeller, D A; Kushner, R F; Neil, K M; Herling-Iaffaldano, K

1995-03-01

To test the benefits of aerobic exercise and dietary carbohydrate during reduced-energy feeding, 23 obese women (44 +/- 4% fat) were randomly assigned to either aerobic exercise (Ex) or no exercise (Nx), and to a low-fat (LF) or low-carbohydrate (LC) reducing diet (5.00 +/- 0.56 MJ/d) for 12 wk. Changes in body composition, postabsorptive resting metabolic rate (RMR), thermic effect of a meal (TEM), and total daily energy expenditure (TDEE) were measured by respiratory gas exchange and doubly labeled water. Significant effects of Ex included a greater loss of fat mass (Ex: -8.8 +/- 2.1 vs Nx: -6.1 +/- 2.3 kg, P = 0.008) and maintenance of TDEE (Ex: +0.07 +/- 1.23 vs Nx: -1.46 +/- 1.04 MJ/d, P = 0.004), due to a difference in physical activity (Ex: +0.75 +/- 1.06 vs Nx: -0.61 +/- 1.03 MJ/d, P = 0.006), which was not attributable solely to the Ex sessions. RMR in both groups decreased comparably (-0.54 MJ/d), and TEM (% of meal) did not change. Diet composition did not significantly influence body composition or energy expenditure changes, but a greater weight loss was observed after the LC than after the LF (-10.6 +/- 2.0 vs -8.1 +/- 3.0 kg, P = 0.037) diet. The addition of aerobic exercise to a low-energy diet was beneficial in the treatment of moderate obesity because of its favorable effects on body composition, physical activity, and TDEE.

Fermentation and aerobic metabolism of cellodextrins by yeasts. [Candida wickerhamii; C. guiliermondii; C. molischiana; Debaryomyces polymorphus; Pichia guilliermondii; Clavispora lusitaniae; Kluyveromyces lactis; Brettanomyces claussenii; Rhodotorula minuta; Dekkera intermedia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Freer, S.N.

1991-03-01

The fermentation and aerobic metabolism of cellodextrins by 14 yeast species or strains was monitored. When grown aerobically, Candida wickerhamii, C. guilliermondii, and C. molischiana metabolized cellodextrins of degree of polymerization 3 to 6. C. wicherhamii and C. molischiana also fermented these substrates, while C. guilliermondii fermented only cellodextrins of degree of polymerization {<=} 3. Debaryomyces polymorphus, Pichia guilliermondii, Clavispora lusitaniae, and one of two strains of Kluyveromyces lactis metabolized glucose, cellobiose, and cellotriose when grown aerobically. These yeasts also fermented these substrates, except for K. lactis, which fermented only glucose and cellobiose. The remaining species/strains tested, K. lactis, Brettanomycesmore » claussenii, Brettanomyces anomalus, Kluyveromyces dobzhanskii, Rhodotorula minuta, and Dekkera intermedia, both fermented and aerobically metabolized glucose and cellobiose. Crude enzyme preparations from all 14 yeast species or strains were tested for ability to hydrolyze cellotriose and cellotretose. Most of the yeasts produced an enzyme(s) capable of hydrolyzing cellotriose. However, with two exceptions, R. minuta and P. guilliermondii, only the yeasts that metabolized cellodextrins of degree of polymerization >3 produced an enzyme(s) that hydrolyzed cellotretose.« less

Chemiosmotic Energy Conservation in Dinoroseobacter shibae: Proton Translocation Driven by Aerobic Respiration, Denitrification, and Photosynthetic Light Reaction.

PubMed

Kirchhoff, Christian; Ebert, Matthias; Jahn, Dieter; Cypionka, Heribert

2018-01-01

Dinoroseobacter shibae is an aerobic anoxygenic phototroph and able to utilize light energy to support its aerobic energy metabolism. Since the cells can also grow anaerobically with nitrate and nitrite as terminal electron acceptor, we were interested in how the cells profit from photosynthesis during denitrification and what the steps of chemiosmotic energy conservation are. Therefore, we conducted proton translocation experiments and compared O 2 - , NO 3 - , and NO 2 - respiration during different light regimes and in the dark. We used wild type cells and transposon mutants with knocked-out nitrate- and nitrite- reductase genes ( napA and nirS ), as well as a mutant ( ppsR ) impaired in bacteriochlorophyll a synthesis. Light had a positive impact on proton translocation, independent of the type of terminal electron acceptor present. In the absence of an electron acceptor, however, light did not stimulate proton translocation. The light-driven add-on to proton translocation was about 1.4 H + /e - for O 2 respiration and about 1.1 H + /e - for NO 3 - and NO 2 - . We could see that the chemiosmotic energy conservation during aerobic respiration involved proton translocation, mediated by the NADH dehydrogenase, the cytochrome bc 1 complex, and the cytochrome c oxidase. During denitrification the last proton translocation step of the electron transport was missing, resulting in a lower H + /e - ratio during anoxia. Furthermore, we studied the type of light-harvesting and found that the cells were able to channel light from the green-blue spectrum most efficiently, while red light has only minor impact. This fits well with the depth profiles for D. shibae abundance in the ocean and the penetration depth of light with different wavelengths into the water column.

Aerobic scope explains individual variation in feeding capacity

PubMed Central

Auer, Sonya K.; Salin, Karine; Anderson, Graeme J.; Metcalfe, Neil B.

2015-01-01

Links between metabolism and components of fitness such as growth, reproduction and survival can depend on food availability. A high standard metabolic rate (SMR; baseline energy expenditure) or aerobic scope (AS; the difference between an individual's maximum and SMR) is often beneficial when food is abundant or easily accessible but can be less important or even disadvantageous when food levels decline. While the mechanisms underlying these context-dependent associations are not well understood, they suggest that individuals with a higher SMR or AS are better able to take advantage of high food abundance. Here we show that juvenile brown trout (Salmo trutta) with a higher AS were able to consume more food per day relative to individuals with a lower AS. These results help explain why a high aerobic capacity can improve performance measures such as growth rate at high but not low levels of food availability. PMID:26556902

Impaired cardiac energy metabolism in embryos lacking adrenergic stimulation.

PubMed

Baker, Candice N; Gidus, Sarah A; Price, George F; Peoples, Jessica N R; Ebert, Steven N

2015-03-01

As development proceeds from the embryonic to fetal stages, cardiac energy demands increase substantially, and oxidative phosphorylation of ADP to ATP in mitochondria becomes vital. Relatively little, however, is known about the signaling mechanisms regulating the transition from anaerobic to aerobic metabolism that occurs during the embryonic period. The main objective of this study was to test the hypothesis that adrenergic hormones provide critical stimulation of energy metabolism during embryonic/fetal development. We examined ATP and ADP concentrations in mouse embryos lacking adrenergic hormones due to targeted disruption of the essential dopamine β-hydroxylase (Dbh) gene. Embryonic ATP concentrations decreased dramatically, whereas ADP concentrations rose such that the ATP/ADP ratio in the adrenergic-deficient group was nearly 50-fold less than that found in littermate controls by embryonic day 11.5. We also found that cardiac extracellular acidification and oxygen consumption rates were significantly decreased, and mitochondria were significantly larger and more branched in adrenergic-deficient hearts. Notably, however, the mitochondria were intact with well-formed cristae, and there was no significant difference observed in mitochondrial membrane potential. Maternal administration of the adrenergic receptor agonists isoproterenol or l-phenylephrine significantly ameliorated the decreases in ATP observed in Dbh-/- embryos, suggesting that α- and β-adrenergic receptors were effective modulators of ATP concentrations in mouse embryos in vivo. These data demonstrate that adrenergic hormones stimulate cardiac energy metabolism during a critical period of embryonic development. Copyright © 2015 the American Physiological Society.

Impaired cardiac energy metabolism in embryos lacking adrenergic stimulation

PubMed Central

Baker, Candice N.; Gidus, Sarah A.; Price, George F.; Peoples, Jessica N. R.

2014-01-01

As development proceeds from the embryonic to fetal stages, cardiac energy demands increase substantially, and oxidative phosphorylation of ADP to ATP in mitochondria becomes vital. Relatively little, however, is known about the signaling mechanisms regulating the transition from anaerobic to aerobic metabolism that occurs during the embryonic period. The main objective of this study was to test the hypothesis that adrenergic hormones provide critical stimulation of energy metabolism during embryonic/fetal development. We examined ATP and ADP concentrations in mouse embryos lacking adrenergic hormones due to targeted disruption of the essential dopamine β-hydroxylase (Dbh) gene. Embryonic ATP concentrations decreased dramatically, whereas ADP concentrations rose such that the ATP/ADP ratio in the adrenergic-deficient group was nearly 50-fold less than that found in littermate controls by embryonic day 11.5. We also found that cardiac extracellular acidification and oxygen consumption rates were significantly decreased, and mitochondria were significantly larger and more branched in adrenergic-deficient hearts. Notably, however, the mitochondria were intact with well-formed cristae, and there was no significant difference observed in mitochondrial membrane potential. Maternal administration of the adrenergic receptor agonists isoproterenol or l-phenylephrine significantly ameliorated the decreases in ATP observed in Dbh−/− embryos, suggesting that α- and β-adrenergic receptors were effective modulators of ATP concentrations in mouse embryos in vivo. These data demonstrate that adrenergic hormones stimulate cardiac energy metabolism during a critical period of embryonic development. PMID:25516547

The Effects of Aerobic Exercise on Estrogen Metabolism in Healthy Premenopausal Women

PubMed Central

Smith, Alma J.; Phipps, William R.; Thomas, William; Schmitz, Kathryn H.; Kurzer, Mindy S.

2013-01-01

Background It is well accepted that exercise can decrease breast cancer risk. Limited clinical evidence suggests that this risk could be mediated through changes in estrogen metabolism in premenopausal women. Our objective was to investigate the effects of exercise on premenopausal estrogen metabolism pertinent to breast cancer risk. Methods Sedentary, healthy, young eumenorrheic women were randomized into an intervention of 30 minutes of moderate-to-vigorous aerobic exercise 5 times a week for approximately 16 weeks (n = 212), or into a usual-lifestyle sedentary control group (n = 179). Urinary levels of estrogens (estrone [E1], estradiol, and estriol) and nine estrogen metabolites were measured at baseline and at study end by liquid chromatography/tandem mass spectrometry. The ratios of 2-hydroxyestrone to 16α-hydroxyestrone (2-OHE1/16α-OHE1) and 2-OHE1 to 4-hydroxyestrone (2- OHE1/4-OHE1) were also calculated. Results The exercise intervention resulted in significant increases in aerobic fitness and lean body mass, and a significant decrease in percent body fat. For exercisers who completed the study (n = 165), 2-OHE1/16α-OHE1 increased significantly (P = 0.043), while E1 decreased significantly (P = 0.030) in control participants (n = 153). The change from baseline in 2-OHE1/16α-OHE1 was significantly different between groups (P = 0.045), even after adjustment for baseline values. Conclusions The exercise intervention resulted in a significant increase in the 2-OHE1/16α-OHE1 ratio, but no differences in other estrogen metabolites or ratios. Impact Our results suggest that changes in premenopausal estrogen metabolism may be a mechanism by which increased physical activity lowers breast cancer risk. PMID:23652373

Global Metabolic Stress of Isoeffort Continuous and High Intensity Interval Aerobic Exercise: A Comparative 1H NMR Metabonomic Study.

PubMed

Zafeiridis, Andreas; Chatziioannou, Anastasia Chrysovalantou; Sarivasiliou, Haralambos; Kyparos, Antonios; Nikolaidis, Michalis G; Vrabas, Ioannis S; Pechlivanis, Alexandros; Zoumpoulakis, Panagiotis; Baskakis, Constantinos; Dipla, Konstantina; Theodoridis, Georgios A

2016-12-02

The overall metabolic/energetic stress that occurs during an acute bout of exercise is proposed to be the main driving force for long-term training adaptations. Continuous and high-intensity interval exercise protocols (HIIE) are currently prescribed to acquire the muscular and metabolic benefits of aerobic training. We applied 1 H NMR-based metabonomics to compare the overall metabolic perturbation and activation of individual bioenergetic pathways of three popular aerobic exercises matched for effort/strain. Nine men performed continuous, long-interval (3 min), and short-interval (30 s) bouts of exercise under isoeffort conditions. Blood was collected before and after exercise. The multivariate PCA and OPLS-DA models showed a distinct separation of pre- and postexercise samples in three protocols. The two models did not discriminate the postexercise overall metabolic profiles of the three exercise types. Analysis focused on muscle bioenergetic pathways revealed an extensive upregulation of carbohydrate-lipid metabolism and the TCA cycle in all three protocols; there were only a few differences among protocols in the postexercise abundance of molecules when long-interval bouts were performed. In conclusion, continuous and HIIE exercise protocols, when performed with similar effort/strain, induce comparable global metabolic response/stress despite their marked differences in work-bout intensities. This study highlights the importance of NMR metabonomics in comprehensive monitoring of metabolic consequences of exercise training in the blood of athletes and exercising individuals.

L-Arginine Affects Aerobic Capacity and Muscle Metabolism in MELAS (Mitochondrial Encephalomyopathy, Lactic Acidosis and Stroke-Like Episodes) Syndrome

PubMed Central

Rodan, Lance H.; Wells, Greg D.; Banks, Laura; Thompson, Sara; Schneiderman, Jane E.; Tein, Ingrid

2015-01-01

Objective To study the effects of L-arginine (L-Arg) on total body aerobic capacity and muscle metabolism as assessed by 31Phosphorus Magnetic Resonance Spectroscopy (31P-MRS) in patients with MELAS (Mitochondrial Encephalomyopathy with Lactic Acidosis and Stroke-like episodes) syndrome. Methods We performed a case control study in 3 MELAS siblings (m.3243A>G tRNAleu(UUR) in MTTL1 gene) with different % blood mutant mtDNA to evaluate total body maximal aerobic capacity (VO2peak) using graded cycle ergometry and muscle metabolism using 31P-MRS. We then ran a clinical trial pilot study in MELAS sibs to assess response of these parameters to single dose and a 6-week steady-state trial of oral L-Arginine. Results At baseline (no L-Arg), MELAS had lower serum Arg (p = 0.001). On 31P-MRS muscle at rest, MELAS subjects had increased phosphocreatine (PCr) (p = 0.05), decreased ATP (p = 0.018), and decreased intracellular Mg2+ (p = 0.0002) when compared to matched controls. With L-arginine therapy, the following trends were noted in MELAS siblings on cycle ergometry: (1) increase in mean % maximum work at anaerobic threshold (AT) (2) increase in % maximum heart rate at AT (3) small increase in VO2peak. On 31P-MRS the following mean trends were noted: (1) A blunted decrease in pH after exercise (less acidosis) (2) increase in Pi/PCr ratio (ADP) suggesting increased work capacity (3) a faster half time of PCr recovery (marker of mitochondrial activity) following 5 minutes of moderate intensity exercise (4) increase in torque. Significance These results suggest an improvement in aerobic capacity and muscle metabolism in MELAS subjects in response to supplementation with L-Arg. Intramyocellular hypomagnesemia is a novel finding that warrants further study. Classification of Evidence Class III evidence that L-arginine improves aerobic capacity and muscle metabolism in MELAS subjects. Trial Registration ClinicalTrials.gov NCT01603446. PMID:25993630

L-Arginine Affects Aerobic Capacity and Muscle Metabolism in MELAS (Mitochondrial Encephalomyopathy, Lactic Acidosis and Stroke-Like Episodes) Syndrome.

PubMed

Rodan, Lance H; Wells, Greg D; Banks, Laura; Thompson, Sara; Schneiderman, Jane E; Tein, Ingrid

2015-01-01

To study the effects of L-arginine (L-Arg) on total body aerobic capacity and muscle metabolism as assessed by (31)Phosphorus Magnetic Resonance Spectroscopy ((31)P-MRS) in patients with MELAS (Mitochondrial Encephalomyopathy with Lactic Acidosis and Stroke-like episodes) syndrome. We performed a case control study in 3 MELAS siblings (m.3243A>G tRNA(leu(UUR)) in MTTL1 gene) with different % blood mutant mtDNA to evaluate total body maximal aerobic capacity (VO(2peak)) using graded cycle ergometry and muscle metabolism using 31P-MRS. We then ran a clinical trial pilot study in MELAS sibs to assess response of these parameters to single dose and a 6-week steady-state trial of oral L-Arginine. At baseline (no L-Arg), MELAS had lower serum Arg (p = 0.001). On 3(1)P-MRS muscle at rest, MELAS subjects had increased phosphocreatine (PCr) (p = 0.05), decreased ATP (p = 0.018), and decreased intracellular Mg(2+) (p = 0.0002) when compared to matched controls. With L-arginine therapy, the following trends were noted in MELAS siblings on cycle ergometry: (1) increase in mean % maximum work at anaerobic threshold (AT) (2) increase in % maximum heart rate at AT (3) small increase in VO(2peak). On (31)P-MRS the following mean trends were noted: (1) A blunted decrease in pH after exercise (less acidosis) (2) increase in Pi/PCr ratio (ADP) suggesting increased work capacity (3) a faster half time of PCr recovery (marker of mitochondrial activity) following 5 minutes of moderate intensity exercise (4) increase in torque. These results suggest an improvement in aerobic capacity and muscle metabolism in MELAS subjects in response to supplementation with L-Arg. Intramyocellular hypomagnesemia is a novel finding that warrants further study. Class III evidence that L-arginine improves aerobic capacity and muscle metabolism in MELAS subjects. ClinicalTrials.gov NCT01603446.

Regulation of Aerobic Energy Metabolism in Podospora anserina by Two Paralogous Genes Encoding Structurally Different c-Subunits of ATP Synthase.

PubMed

Sellem, Carole H; di Rago, Jean-Paul; Lasserre, Jean-Paul; Ackerman, Sharon H; Sainsard-Chanet, Annie

2016-07-01

Most of the ATP in living cells is produced by an F-type ATP synthase. This enzyme uses the energy of a transmembrane electrochemical proton gradient to synthesize ATP from ADP and inorganic phosphate. Proton movements across the membrane domain (FO) of the ATP synthase drive the rotation of a ring of 8-15 c-subunits, which induces conformational changes in the catalytic part (F1) of the enzyme that ultimately promote ATP synthesis. Two paralogous nuclear genes, called Atp9-5 and Atp9-7, encode structurally different c-subunits in the filamentous fungus Podospora anserina. We have in this study identified differences in the expression pattern for the two genes that correlate with the mitotic activity of cells in vegetative mycelia: Atp9-7 is transcriptionally active in non-proliferating (stationary) cells while Atp9-5 is expressed in the cells at the extremity (apex) of filaments that divide and are responsible for mycelium growth. When active, the Atp9-5 gene sustains a much higher rate of c-subunit synthesis than Atp9-7. We further show that the ATP9-7 and ATP9-5 proteins have antagonist effects on the longevity of P. anserina. Finally, we provide evidence that the ATP9-5 protein sustains a higher rate of mitochondrial ATP synthesis and yield in ATP molecules per electron transferred to oxygen than the c-subunit encoded by Atp9-7. These findings reveal that the c-subunit genes play a key role in the modulation of ATP synthase production and activity along the life cycle of P. anserina. Such a degree of sophistication for regulating aerobic energy metabolism has not been described before.

Change in energy expenditure and physical activity in response to aerobic and resistance exercise programs.

PubMed

Drenowatz, Clemens; Grieve, George L; DeMello, Madison M

2015-01-01

Exercise is considered an important component of a healthy lifestyle but there remains controversy on effects of exercise on non-exercise physical activity (PA). The present study examined the prospective association of aerobic and resistance exercise with total daily energy expenditure and PA in previously sedentary, young men. Nine men (27.0 ± 3.3 years) completed two 16-week exercise programs (3 exercise sessions per week) of aerobic and resistance exercise separated by a minimum of 6 weeks in random order. Energy expenditure and PA were measured with the SenseWear Mini Armband prior to each intervention as well as during week 1, week 8 and week 16 of the aerobic and resistance exercise program. Body composition was measured via dual x-ray absorptiometry. Body composition did not change in response to either exercise intervention. Total daily energy expenditure on exercise days increased by 443 ± 126 kcal/d and 239 ± 152 kcal/d for aerobic and resistance exercise, respectively (p < 0.01). Non-exercise moderate-to-vigorous PA, however, decreased on aerobic exercise days (-148 ± 161 kcal/d; p = 0.03). There was no change in total daily energy expenditure and PA on non-exercise days with aerobic exercise while resistance exercise was associated with an increase in moderate-to-vigorous PA during non-exercise days (216 ± 178 kcal/d, p = 0.01). Results of the present study suggest a compensatory reduction in PA in response to aerobic exercise. Resistance exercise, on the other hand, appears to facilitate non-exercise PA, particularly on non-exercise days, which may lead to more sustainable adaptations in response to an exercise program.

Aerobic metabolism in the genus Lactobacillus: impact on stress response and potential applications in the food industry.

PubMed

Zotta, T; Parente, E; Ricciardi, A

2017-04-01

This review outlines the recent advances in the knowledge on aerobic and respiratory growth of lactic acid bacteria, focusing on the features of respiration-competent lactobacilli. The species of the genus Lactobacillus have been traditionally classified as oxygen-tolerant anaerobes, but it has been demonstrated that several strains are able to use oxygen as a substrate in reactions mediated by flavin oxidases and, in some cases, to synthesize a minimal respiratory chain. The occurrence of genes related to aerobic and respiratory metabolism and to oxidative stress response apparently correlates with the taxonomic position of lactobacilli. Members of the ecologically versatile Lactobacillus casei, L. plantarum and L. sakei groups are apparently best equipped to deal with aerobic/respiratory growth. The shift from anaerobic growth to aerobic (oxygen) and/or respiratory promoting (oxygen, exogenous haem and menaquinone) conditions offers physiological advantages and affects the pattern of metabolite production in several species. Even if this does not result in dramatic increases in biomass production and growth rate, cells grown in these conditions have improved tolerance to heat and oxidative stresses. An overview of benefits and of the potential applications of Lactobacillus cultures grown under aerobic or respiratory conditions is also discussed. © 2017 The Society for Applied Microbiology.

Eight-Week Training Cessation Suppresses Physiological Stress but Rapidly Impairs Health Metabolic Profiles and Aerobic Capacity in Elite Taekwondo Athletes.

PubMed

Liao, Yi-Hung; Sung, Yu-Chi; Chou, Chun-Chung; Chen, Chung-Yu

2016-01-01

Changes in an athlete's physiological and health metabolic profiles after detraining have not been studied in elite Taekwondo (TKD) athletes. To enable a better understanding of these physiological changes to training cessation, this study examined the effects of 8-weeks detraining on the aerobic capacity, body composition, inflammatory status and health metabolic profile in elite TKD athletes. Sixteen elite TKD athletes (age: 21.0 ± 0.8 yrs, BMI: 22.4 ± 3.9 kg/m2; Mean ± SD; 11 males and 5 females) participated in this study. Physical activity level assessment using computerized physical activity logs was performed during the competitive preparation season (i.e. one-week before national competition) and at two week intervals throughout the detraining period. Participant aerobic capacity, body fat, and blood biomarkers were measured before and after detraining, and the blood biomarker analyses included leukocyte subpopulations, blood glucose, insulin, dehydroepiandrosterone-sulfate (DHEA-S), and cortisol. Eight-week detraining increased DHEA-S/cortisol ratio (+57.3%, p = 0.004), increased insulin/cortisol ratio (+59.9%, p = 0.004), reduced aerobic power (-2.43%, p = 0.043), increased body fat accumulation (body fat%: +21.3%, p < 0.001), decreased muscle mass (muscle mass%: -4.04%, p < 0.001), and elevated HOMA-IR (the biomarker of systemic insulin resistance; +34.2%, p = 0.006). The neutrophil-to-lymphocyte ratio (NLR), a systemic inflammatory index, increased by 48.2% (p = 0.005). The change in aerobic capacity was correlated with the increased fat mass (r = -0.429, p = 0.049) but not with muscle loss. An increase in the NLR was correlated to the changes in HOMA-IR (r = 0.44, p = 0.044) and aerobic capacity (r = -0.439, p = 0.045). We demonstrate that 8-week detraining suppresses physiological stress but rapidly results in declines in athletic performance and health metabolic profiles, including reduced aerobic capacity, increased body fat, muscle loss, insulin

Evaluation of energy consumption during aerobic sewage sludge treatment in dairy wastewater treatment plant.

PubMed

Dąbrowski, Wojciech; Żyłka, Radosław; Malinowski, Paweł

2017-02-01

The subject of the research conducted in an operating dairy wastewater treatment plant (WWTP) was to examine electric energy consumption during sewage sludge treatment. The excess sewage sludge was aerobically stabilized and dewatered with a screw press. Organic matter varied from 48% to 56% in sludge after stabilization and dewatering. It proves that sludge was properly stabilized and it was possible to apply it as a fertilizer. Measurement factors for electric energy consumption for mechanically dewatered sewage sludge were determined, which ranged between 0.94 and 1.5 kWhm -3 with the average value at 1.17 kWhm -3 . The shares of devices used for sludge dewatering and aerobic stabilization in the total energy consumption of the plant were also established, which were 3% and 25% respectively. A model of energy consumption during sewage sludge treatment was estimated according to experimental data. Two models were applied: linear regression for dewatering process and segmented linear regression for aerobic stabilization. The segmented linear regression model was also applied to total energy consumption during sewage sludge treatment in the examined dairy WWTP. The research constitutes an introduction for further studies on defining a mathematical model used to optimize electric energy consumption by dairy WWTPs. Copyright © 2016 Elsevier Inc. All rights reserved.

Electron transfer to nitrogenase in different genomic and metabolic backgrounds.

PubMed

Poudel, Saroj; Colman, Daniel R; Fixen, Kathryn R; Ledbetter, Rhesa N; Zheng, Yanning; Pence, Natasha; Seefeldt, Lance C; Peters, John W; Harwood, Caroline S; Boyd, Eric S

2018-02-26

Nitrogenase catalyzes the reduction of dinitrogen (N 2 ) using low potential electrons from ferredoxin (Fd) or flavodoxin (Fld) through an ATP dependent process. Since its emergence in an anaerobic chemoautotroph, this oxygen (O 2 ) sensitive enzyme complex has evolved to operate in a variety of genomic and metabolic backgrounds including those of aerobes, anaerobes, chemotrophs, and phototrophs. However, whether pathways of electron delivery to nitrogenase are influenced by these different metabolic backgrounds is not well understood. Here, we report the distribution of homologs of Fds, Flds, and Fd/Fld-reducing enzymes in 359 genomes of putative N 2 fixers (diazotrophs). Six distinct lineages of nitrogenase were identified and their distributions largely corresponded to differences in the host cells' ability to integrate O 2 or light into energy metabolism. Predicted pathways of electron transfer to nitrogenase in aerobes, facultative anaerobes, and phototrophs varied from those in anaerobes at the level of Fds/Flds used to reduce nitrogenase, the enzymes that generate reduced Fds/Flds, and the putative substrates of these enzymes. Proteins that putatively reduce Fd with hydrogen or pyruvate were enriched in anaerobes, while those that reduce Fd with NADH/NADPH were enriched in aerobes, facultative anaerobes, and anoxygenic phototrophs. The energy metabolism of aerobic, facultatively anaerobic, and anoxygenic phototrophic diazotrophs often yields reduced NADH/NADPH that is not sufficiently reduced to drive N 2 reduction. At least two mechanisms have been acquired by these taxa to overcome this limitation and to generate electrons with potentials capable of reducing Fd. These include the bifurcation of electrons or the coupling of Fd reduction to reverse ion translocation. IMPORTANCE Nitrogen fixation supplies fixed nitrogen to cells from a variety of genomic and metabolic backgrounds including those of aerobes, facultative anaerobes, chemotrophs, and phototrophs

Extramitochondrial energy production in platelets.

PubMed

Ravera, Silvia; Signorello, Maria Grazia; Bartolucci, Martina; Ferrando, Sara; Manni, Lucia; Caicci, Federico; Calzia, Daniela; Panfoli, Isabella; Morelli, Alessandro; Leoncini, Giuliana

2018-05-01

Energy demand in human platelets is very high, to carry out their functions. As for most human cells, the aerobic metabolism represents the primary energy source in platelets, even though mitochondria are negligibly represented. Following the hypothesis that other structures could be involved in chemical energy production, in this work, we have investigated the functional expression of an extramitochondrial aerobic metabolism in platelets. Oximetric and luminometric analyses showed that platelets consume large amounts of oxygen and produce ATP in the presence of common respiring substrates, such as pyruvate + malate or succinate, although morphological electron microscopy analysis showed that these contain few mitochondria. However, evaluation of the anaerobic glycolytic metabolism showed that only 13% of consumed glucose was converted to lactate. Interestingly, the highest OXPHOS activity was observed in the presence of NADH, not a readily permeant respiring substrate for mitochondria. Also, oxygen consumption and ATP synthesis fuelled by NADH were not affected by atractyloside, an inhibitor of the adenine nucleotide translocase, suggesting that these processes may not be ascribed to mitochondria. Functional data were confirmed by immunofluorescence microscopy and Western blot analyses, showing a consistent expression of the β subunit of F 1 F o -ATP synthase and COXII, a subunit of Complex IV, but a low signal of translocase of the inner mitochondrial membrane (a protein not involved in OXPHOS metabolism). Interestingly, the NADH-stimulated oxygen consumption and ATP synthesis increased in the presence of the physiological platelets agonists, thrombin or collagen. Data suggest that in platelets, aerobic energy production is mainly driven by an extramitochondrial OXPHOS machinery, originated inside the megakaryocyte, and that this metabolism plays a pivotal role in platelet activation. This work represents a further example of the existence of an

Demyelination in Multiple Sclerosis: Reprogramming Energy Metabolism and Potential PPARγ Agonist Treatment Approaches

PubMed Central

Lecarpentier, Yves; Guillevin, Rémy; Vallée, Jean-Noël

2018-01-01

Demyelination in multiple sclerosis (MS) cells is the site of several energy metabolic abnormalities driven by dysregulation between the opposed interplay of peroxisome proliferator-activated receptor γ (PPARγ) and WNT/β-catenin pathways. We focus our review on the opposing interactions observed in demyelinating processes in MS between the canonical WNT/β-catenin pathway and PPARγ and their reprogramming energy metabolism implications. Demyelination in MS is associated with chronic inflammation, which is itself associated with the release of cytokines by CD4+ Th17 cells, and downregulation of PPARγ expression leading to the upregulation of the WNT/β-catenin pathway. Upregulation of WNT/β-catenin signaling induces activation of glycolytic enzymes that modify their energy metabolic behavior. Then, in MS cells, a large portion of cytosolic pyruvate is converted into lactate. This phenomenon is called the Warburg effect, despite the availability of oxygen. The Warburg effect is the shift of an energy transfer production from mitochondrial oxidative phosphorylation to aerobic glycolysis. Lactate production is correlated with increased WNT/β-catenin signaling and demyelinating processes by inducing dysfunction of CD4+ T cells leading to axonal and neuronal damage. In MS, downregulation of PPARγ decreases insulin sensitivity and increases neuroinflammation. PPARγ agonists inhibit Th17 differentiation in CD4+ T cells and then diminish release of cytokines. In MS, abnormalities in the regulation of circadian rhythms stimulate the WNT pathway to initiate the demyelination process. Moreover, PPARγ contributes to the regulation of some key circadian genes. Thus, PPARγ agonists interfere with reprogramming energy metabolism by directly inhibiting the WNT/β-catenin pathway and circadian rhythms and could appear as promising treatments in MS due to these interactions. PMID:29659554

Potential hepatic toxicity of buprofezin at sublethal concentrations: ROS-mediated conversion of energy metabolism.

PubMed

Ji, Xiaotong; Ku, Tingting; Zhu, Na; Ning, Xia; Wei, Wei; Li, Guangke; Sang, Nan

2016-12-15

Buprofezin is known for its broad-spectrum action and environmental safety. The popularity of buprofezin has raised concerns about its potentially adverse effects on human health and risk to the environment. In this study, we first identified the liver as one of the major organs in which buprofezin accumulated, and we detected a severe oxidative stress response. Next, we demonstrated that sublethal concentrations of buprofezin promoted the conversion of energy metabolism from the aerobic tricarboxylic acid (TCA) cycle and oxidative phosphorylation to anaerobic glycolysis. Importantly, reactive oxygen species (ROS) generation partially accounted for the shunting of the energy metabolism through the buprofezin-mediated inhibition of cytochrome c oxidase activity. ROS directly perturbed the activities of several key TCA cycle enzymes, stimulated glycolysis, and indirectly disturbed the activity of the respiratory chain complex by altering mitochondrial DNA (mtDNA). These findings clarify the potential mechanisms of buprofezin toxicity and provide biomarkers for buprofezin-mediated hepatotoxicity at sublethal concentrations. Copyright © 2016 Elsevier B.V. All rights reserved.

Astrocytes and energy metabolism.

PubMed

Prebil, Mateja; Jensen, Jørgen; Zorec, Robert; Kreft, Marko

2011-05-01

Astrocytes are glial cells, which play a significant role in a number of processes, including the brain energy metabolism. Their anatomical position between blood vessels and neurons make them an interface for effective glucose uptake from blood. After entering astrocytes, glucose can be involved in different metabolic pathways, e.g. in glycogen production. Glycogen in the brain is localized mainly in astrocytes and is an important energy source in hypoxic conditions and normal brain functioning. The portion of glucose metabolized into glycogen molecules in astrocytes is as high as 40%. It is thought that the release of gliotransmitters (such as glutamate, neuroactive peptides and ATP) into the extracellular space by regulated exocytosis supports a significant part of communication between astrocytes and neurons. On the other hand, neurotransmitter action on astrocytes has a significant role in brain energy metabolism. Therefore, understanding the astrocytes energy metabolism may help understanding neuron-astrocyte interactions.

Voluntary Running Attenuates Metabolic Dysfunction in Ovariectomized Low-Fit Rats

PubMed Central

Park, Young-Min; Padilla, Jaume; Kanaley, Jill A.; Zidon, Terese; Welly, Rebecca J.; Britton, Steven L.; Koch, Lauren G.; Thyfault, John P.; Booth, Frank W.; Vieira-Potter, Victoria J.

2016-01-01

INTRODUCTION Ovariectomy and high fat diet (HFD) worsen obesity and metabolic dysfunction associated with low aerobic fitness. Exercise training mitigates metabolic abnormalities induced by low aerobic fitness, but whether the protective effect is maintained following ovariectomy and HFD is unknown. PURPOSE This study determined whether, following ovariectomy and HFD, exercise training improves metabolic function in rats bred for low intrinsic aerobic capacity. METHODS Female rats selectively bred for low (LCR) and high (HCR) intrinsic aerobic capacity (n=30) were ovariectomized, fed HFD, and randomized to either a sedentary (SED) or voluntary wheel running (EX) group. Resting energy expenditure, glucose tolerance, and spontaneous physical activity were determined midway through the experiment, while body weight, wheel running volume, and food intake were assessed throughout the study. Body composition, circulating metabolic markers, and skeletal muscle gene and protein expression was measured at sacrifice. RESULTS EX reduced body weight and adiposity in LCR rats (−10% and −50%, respectively; P<0.05) and, unexpectedly, increased these variables in HCR rats (+7% and +37%, respectively; P<0.05) compared to their respective SED controls, likely due to dietary overcompensation. Wheel running volume was ~5-fold greater in HCR than LCR rats, yet EX enhanced insulin sensitivity equally in LCR and HCR rats (P<0.05). This EX-mediated improvement in metabolic function was associated with gene up-regulation of skeletal muscle IL-6&-10. EX also increased resting energy expenditure, skeletal muscle mitochondrial content (oxidative phosphorylation complexes and citrate synthase activity), and AMPK activation similarly in both lines (all P <0.05). CONCLUSION Despite a 5-fold difference in running volume between rat lines, EX similarly improved systemic insulin sensitivity, resting energy expenditure, and skeletal muscle mitochondrial content and AMPK activation in

An obligately aerobic soil bacterium activates fermentative hydrogen production to survive reductive stress during hypoxia.

PubMed

Berney, Michael; Greening, Chris; Conrad, Ralf; Jacobs, William R; Cook, Gregory M

2014-08-05

Oxygen availability is a major factor and evolutionary force determining the metabolic strategy of bacteria colonizing an environmental niche. In the soil, conditions can switch rapidly between oxia and anoxia, forcing soil bacteria to remodel their energy metabolism accordingly. Mycobacterium is a dominant genus in the soil, and all its species are obligate aerobes. Here we show that an obligate aerobe, the soil actinomycete Mycobacterium smegmatis, adopts an anaerobe-type strategy by activating fermentative hydrogen production to adapt to hypoxia. This process is controlled by the two-component system DosR-DosS/DosT, an oxygen and redox sensor that is well conserved in mycobacteria. We show that DosR tightly regulates the two [NiFe]-hydrogenases: Hyd3 (MSMEG_3931-3928) and Hyd2 (MSMEG_2719-2718). Using genetic manipulation and high-sensitivity GC, we demonstrate that Hyd3 facilitates the evolution of H2 when oxygen is depleted. Combined activity of Hyd2 and Hyd3 was necessary to maintain an optimal NAD(+)/NADH ratio and enhanced adaptation to and survival of hypoxia. We demonstrate that fermentatively-produced hydrogen can be recycled when fumarate or oxygen become available, suggesting Mycobacterium smegmatis can switch between fermentation, anaerobic respiration, and aerobic respiration. Hydrogen metabolism enables this obligate aerobe to rapidly meet its energetic needs when switching between microoxic and anoxic conditions and provides a competitive advantage in low oxygen environments.

Effects of High-Intensity Training on Anaerobic and Aerobic Contributions to Total Energy Release During Repeated Supramaximal Exercise in Obese Adults.

PubMed

Jabbour, Georges; Iancu, Horia-Daniel; Paulin, Anne

Studying relative anaerobic and aerobic metabolism contributions to total energy release during exercise may be valuable in understanding exercise energetic demands and the energetic adaptations that occur in response to acute or chronic exercise in obese adults. The aim of the present study is to evaluate the effects of 6 weeks of high-intensity training (HIT) on relative anaerobic and aerobic contributions to total energy release and on peak power output during repeated supramaximal cycling exercises (SCE) in obese adults. Twenty-four obese adults (body mass index = ± 33 kg.m -2 ) were randomized into a control group ( n  = 12) and an HIT group ( n  = 12). Accumulated oxygen deficits (ml.min -1 ) and anaerobic and aerobic contributions (%) were measured in all groups before and after training via repeated SCE. In addition, the peak power output performed during SCE was determined using the force-velocity test. Before HIT, anaerobic contributions to repeated SCE did not differ between the groups and decreased significantly during the third and fourth repetitions. After HIT, anaerobic contributions increased significantly in the HIT group (+11 %, p  < 0.01) and were significantly higher than those of the control group ( p  < 0.01). Moreover, the peak power obtained during SCE increased significantly in the HIT group (+110 W.kg -1 , p  < 0.01) and correlated positively with increases in anaerobic contributions ( r  = 0.9, p  < 0.01). In obese adults, HIT increased anaerobic contributions to energy release which were associated with peak power enhancement in response to repeated SCE. Consequently, HIT may be an appropriate approach for improving energy contributions and muscle power among obese adults.

Proof of Concept to Isolate and Culture Primary Muscle Cells from Northern Elephant Seals to Study the Mechanisms that Maintain Aerobic Metabolism Under the Hypoxic Conditions of Breath-hold Diving

DTIC Science & Technology

2013-09-30

Cells from Northern Elephant Seals to Study the Mechanisms that Maintain Aerobic Metabolism Under the Hypoxic Conditions of Breath-hold Diving...Muscle Cells from Northern Elephant Seals to Study the Mechanisms that Maintain Aerobic Metabolism Under the Hypoxic Conditions of Breath-hold Diving 5a...two day period in September, 2012. The first major huddle to the study was to determine the effect of the overnight shipping of the viability of

Proof of Concept to Isolate and Culture Primary Muscle Cells from Northern Elephant Seals to Study the Mechanisms that Maintain Aerobic Metabolism Under the Hypoxic Conditions of Breath-Hold Diving

DTIC Science & Technology

2014-09-30

that are too small have less effective results with mechanical trituration that follows digestion). 5. Move dish and sample into the cell culture...Cells from Northern Elephant Seals to Study the Mechanisms that Maintain Aerobic Metabolism Under the Hypoxic Conditions of Breath-Hold Diving...Muscle Cells from Northern Elephant Seals to Study the Mechanisms that Maintain Aerobic Metabolism Under the Hypoxic Conditions of Breath-Hold Diving 5a

Metabolic energy required for flight

NASA Astrophysics Data System (ADS)

Lane, H. W.; Gretebeck, R. J.

1994-11-01

This paper reviews data available from U.S. and U.S.S.R. studies on energy metabolism in the microgravity of space flight. Energy utilization and energy availability in space seem to be similar to those on Earth. However, negative nitrogen balances in space in the presence of adequate energy and protein intakes and in-flight exercise, suggest that lean body mass decreases in space. Metabolic studies during simulated (bed rest) and actual microgravity have shown changes in blood glucose, fatty acids, and insulin levels, suggesting that energy metabolism may be altered during flight. Future research should focus on the interactions of lean body mass, diet, and exercise in space and their roles in energy metabolism during space flight.

Metabolic energy required for flight

NASA Technical Reports Server (NTRS)

Lane, H. W.; Gretebeck, R. J.

1994-01-01

This paper reviews data available from U.S. and U.S.S.R. studies on energy metabolism in the microgravity of space flight. Energy utilization and energy availability in space seem to be similar to those on Earth. However, negative nitrogen balances in space in the presence of adequate energy and protein intakes and in-flight exercise, suggest that lean body mass decreases in space. Metabolic studies during simulated (bed rest) and actual microgravity have shown changes in blood glucose, fatty acids, and insulin levels, suggesting that energy metabolism may be altered during flight. Future research should focus on the interactions of lean body mass, diet, and exercise in spaced and their roles in energy metabolism during space flight.

In vivo aerobic metabolism of the rainbow trout gut and the effects of an acute temperature increase and stress event.

PubMed

Brijs, Jeroen; Gräns, Albin; Hjelmstedt, Per; Sandblom, Erik; van Nuland, Nicole; Berg, Charlotte; Axelsson, Michael

2018-05-24

The fish gut is responsible for numerous potentially energetically costly processes, yet, little is known about its metabolism. Here, we provide the first in vivo measurements for aerobic metabolism of the gut in a teleost fish by measuring gut blood flow, as well as arterial and portal venous oxygen content. At 10°C, gut oxygen uptake rates were 4.3±0.5 ml O 2 h -1 kg -1 (∼11% of whole animal oxygen uptake). Following acute warming to 15°C, gut blood flow increased ∼3.4-fold and gut oxygen uptake rate increased ∼3.7-fold (16.0±3.3 ml O 2 h -1 kg -1 ), now representing ∼25% of whole animal oxygen uptake. Although gut blood flow decreased following an acute stress event at 15°C, gut oxygen uptake remained unchanged due to a ∼2-fold increase in oxygen extraction. The high metabolic thermal sensitivity of the gut discovered here could have important implications on the overall aerobic capacity and performance of fish and warrants further investigations. © 2018. Published by The Company of Biologists Ltd.

Influence of substrate surface loading on the kinetic behaviour of aerobic granules.

PubMed

Liu, Yu; Liu, Yong-Qiang; Wang, Zhi-Wu; Yang, Shu-Fang; Tay, Joo-Hwa

2005-06-01

In the aerobic granular sludge reactor, the substrate loading is related to the size of the aerobic granules cultivated. This study investigated the influence of substrate surface loading on the growth and substrate-utilization kinetics of aerobic granules. Results showed that microbial surface growth rate and surface biodegradation rate are fairly related to the substrate surface loading by the Monod-type equation. In this study, both the theoretical maximum growth yield and the Pirt maintenance coefficient were determined. It was found that the estimated theoretical maximum growth yield of aerobic granules was as low as 0.2 g biomass g(-1) chemical oxygen demand (COD) and 10-40% of input substrate-COD was consumed through the maintenance metabolism, while experimental results further showed that the unit oxygen uptake by aerobic granules was 0.68 g oxygen g(-1) COD, which was much higher than that reported in activated sludge processes. Based on the growth yield and unit oxygen uptake determined, an oxidative assimilation equation of acetate-fed aerobic granules was derived; and this was confirmed by respirometric tests. In aerobic granular culture, about 74% of the input substrate-carbon was converted to carbon dioxide. The growth yield of aerobic granules was three times lower than that of activated sludge. It is likely that high carbon dioxide production is the main cause of the low growth yield of aerobic granules, indicating a possible energy uncoupling in aerobic granular culture.

SU-E-J-102: Separation of Metabolic Supply and Demand: From Power Grid Economics to Cancer Metabolism

DOE Office of Scientific and Technical Information (OSTI.GOV)

Epstein, T; Xu, L; Gillies, R

2014-06-01

Purpose: To study a new model of glucose metabolism which is primarily governed by the timescale of the energetic demand and not by the oxygen level, and its implication on cancer metabolism (Warburg effect) Methods: 1) Metabolic profiling of membrane transporters activity in several cell lines, which represent the spectrum from normal breast epithelium to aggressive, metastatic cancer, using Seahorse XF reader.2) Spatial localization of oxidative and non-oxidative metabolic components using immunocytochemical imaging of the glycolytic ATP-producing enzyme, pyruvate kinase and mitochondria. 3) Finite element simulations of coupled partial differential equations using COMSOL and MATLAB. Results: Inhibition or activation ofmore » pumps on the cell membrane led to reduction or increase in aerobic glycolysis, respectively, while oxidative phosphorylation remained unchanged. These results were consistent with computational simulations of changes in short-timescale demand for energy by cell membrane processes. A specific model prediction was that the spatial distribution of ATP-producing enzymes in the glycolytic pathway must be primarily localized adjacent to the cell membrane, while mitochondria should be predominantly peri-nuclear. These predictions were confirmed experimentally. Conclusion: The results in this work support a new model for glucose metabolism in which glycolysis and oxidative phosphorylation supply different types of energy demand. Similar to power grid economics, optimal metabolic control requires the two pathways, even in normoxic conditions, to match two different types of energy demands. Cells use aerobic metabolism to meet baseline, steady energy demand and glycolytic metabolism to meet short-timescale energy demands, mainly from membrane transport activities, even in the presence of oxygen. This model provides a mechanism for the origin of the Warburg effect in cancer cells. Here, the Warburg effect emerges during carcinogenesis is a

Demyelination in Multiple Sclerosis: Reprogramming Energy Metabolism and Potential PPARγ Agonist Treatment Approaches.

PubMed

Vallée, Alexandre; Lecarpentier, Yves; Guillevin, Rémy; Vallée, Jean-Noël

2018-04-16

Demyelination in multiple sclerosis (MS) cells is the site of several energy metabolic abnormalities driven by dysregulation between the opposed interplay of peroxisome proliferator-activated receptor γ (PPARγ) and WNT/β-catenin pathways. We focus our review on the opposing interactions observed in demyelinating processes in MS between the canonical WNT/β-catenin pathway and PPARγ and their reprogramming energy metabolism implications. Demyelination in MS is associated with chronic inflammation, which is itself associated with the release of cytokines by CD4⁺ Th17 cells, and downregulation of PPARγ expression leading to the upregulation of the WNT/β-catenin pathway. Upregulation of WNT/β-catenin signaling induces activation of glycolytic enzymes that modify their energy metabolic behavior. Then, in MS cells, a large portion of cytosolic pyruvate is converted into lactate. This phenomenon is called the Warburg effect, despite the availability of oxygen. The Warburg effect is the shift of an energy transfer production from mitochondrial oxidative phosphorylation to aerobic glycolysis. Lactate production is correlated with increased WNT/β-catenin signaling and demyelinating processes by inducing dysfunction of CD4⁺ T cells leading to axonal and neuronal damage. In MS, downregulation of PPARγ decreases insulin sensitivity and increases neuroinflammation. PPARγ agonists inhibit Th17 differentiation in CD4⁺ T cells and then diminish release of cytokines. In MS, abnormalities in the regulation of circadian rhythms stimulate the WNT pathway to initiate the demyelination process. Moreover, PPARγ contributes to the regulation of some key circadian genes. Thus, PPARγ agonists interfere with reprogramming energy metabolism by directly inhibiting the WNT/β-catenin pathway and circadian rhythms and could appear as promising treatments in MS due to these interactions.

Effects of smoking and aerobic exercise on male college students' metabolic syndrome risk factors.

PubMed

Kim, Jee-Youn; Yang, Yuhao; Sim, Young-Je

2018-04-01

[Purpose] The aim was to investigate the effects of university students' smoking and aerobic exercise on metabolic syndrome risk factors. [Subjects and Methods] Twenty-three male students were randomly assigned to the following groups: exercise smoker (n=6), non-exercise smoker (n=6), exercise non-smoker (n=6), and non-exercise non-smoker (n=5). A basketball exercise program was conducted three times per week (70 minutes per session) for 8 weeks with exercise intensity set at 50-80% of heart rate reserve. After 8 weeks, the variables of risk factors for metabolic syndrome were obtained. [Results] Systolic blood pressure and diastolic blood pressure were significantly decreased in the exercise non-smoker group and significantly increased in the non-exercise smoker group. Waist circumference was significantly reduced in both exercise groups regardless of smoking and significantly increased in the non-exercise smoker group. Triglyceride, high-density lipoprotein-cholesterol, and fasting plasma glucose showed no differences between the groups. [Conclusion] Obesity and smoking management should be conducted together for students as well as for those with metabolic syndrome risk factors. It is recommended that more students participate in such programs, and exercise programs should be further developed and diversified to prevent metabolic syndrome and cardiovascular diseases.

Epilepsy and astrocyte energy metabolism.

PubMed

Boison, Detlev; Steinhäuser, Christian

2018-06-01

Epilepsy is a complex neurological syndrome characterized by neuronal hyperexcitability and sudden, synchronized electrical discharges that can manifest as seizures. It is now increasingly recognized that impaired astrocyte function and energy homeostasis play key roles in the pathogenesis of epilepsy. Excessive neuronal discharges can only happen, if adequate energy sources are made available to neurons. Conversely, energy depletion during seizures is an endogenous mechanism of seizure termination. Astrocytes control neuronal energy homeostasis through neurometabolic coupling. In this review, we will discuss how astrocyte dysfunction in epilepsy leads to distortion of key metabolic and biochemical mechanisms. Dysfunctional glutamate metabolism in astrocytes can directly contribute to neuronal hyperexcitability. Closure of astrocyte intercellular gap junction coupling as observed early during epileptogenesis limits activity-dependent trafficking of energy metabolites, but also impairs clearance of the extracellular space from accumulation of K + and glutamate. Dysfunctional astrocytes also increase the metabolism of adenosine, a metabolic product of ATP degradation that broadly inhibits energy-consuming processes as an evolutionary adaptation to conserve energy. Due to the critical role of astroglial energy homeostasis in the control of neuronal excitability, metabolic therapeutic approaches that prevent the utilization of glucose might represent a potent antiepileptic strategy. In particular, high fat low carbohydrate "ketogenic diets" as well as inhibitors of glycolysis and lactate metabolism are of growing interest for the therapy of epilepsy. © 2017 Wiley Periodicals, Inc.

An obligately aerobic soil bacterium activates fermentative hydrogen production to survive reductive stress during hypoxia

PubMed Central

Berney, Michael; Greening, Chris; Conrad, Ralf; Jacobs, William R.; Cook, Gregory M.

2014-01-01

Oxygen availability is a major factor and evolutionary force determining the metabolic strategy of bacteria colonizing an environmental niche. In the soil, conditions can switch rapidly between oxia and anoxia, forcing soil bacteria to remodel their energy metabolism accordingly. Mycobacterium is a dominant genus in the soil, and all its species are obligate aerobes. Here we show that an obligate aerobe, the soil actinomycete Mycobacterium smegmatis, adopts an anaerobe-type strategy by activating fermentative hydrogen production to adapt to hypoxia. This process is controlled by the two-component system DosR-DosS/DosT, an oxygen and redox sensor that is well conserved in mycobacteria. We show that DosR tightly regulates the two [NiFe]-hydrogenases: Hyd3 (MSMEG_3931-3928) and Hyd2 (MSMEG_2719-2718). Using genetic manipulation and high-sensitivity GC, we demonstrate that Hyd3 facilitates the evolution of H2 when oxygen is depleted. Combined activity of Hyd2 and Hyd3 was necessary to maintain an optimal NAD+/NADH ratio and enhanced adaptation to and survival of hypoxia. We demonstrate that fermentatively-produced hydrogen can be recycled when fumarate or oxygen become available, suggesting Mycobacterium smegmatis can switch between fermentation, anaerobic respiration, and aerobic respiration. Hydrogen metabolism enables this obligate aerobe to rapidly meet its energetic needs when switching between microoxic and anoxic conditions and provides a competitive advantage in low oxygen environments. PMID:25049411

Effects of Aerobic Exercise on Mild Cognitive Impairment

PubMed Central

Baker, Laura D.; Frank, Laura L.; Foster-Schubert, Karen; Green, Pattie S.; Wilkinson, Charles W.; McTiernan, Anne; Plymate, Stephen R.; Fishel, Mark A.; Stennis Watson, G.; Cholerton, Brenna A.; Duncan, Glen E.; Mehta, Pankaj D.; Craft, Suzanne

2011-01-01

Objectives To examine the effects of aerobic exercise on cognition and other biomarkers associated with Alzheimer disease pathology for older adults with mild cognitive impairment, and assess the role of sex as a predictor of response. Design Six-month, randomized, controlled, clinical trial. Setting Veterans Affairs Puget Sound Health Care System clinical research unit. Participants Thirty-three adults (17 women) with amnestic mild cognitive impairment ranging in age from 55 to 85 years (mean age,70 years). Intervention Participants were randomized either to a high-intensity aerobic exercise or stretching control group. The aerobic group exercised under the supervision of a fitness trainer at 75% to 85% of heart rate reserve for 45 to 60 min/d, 4 d/wk for 6 months. The control group carried out supervised stretching activities according to the same schedule but maintained their heart rate at or below 50% of their heart rate reserve. Before and after the study, glucometabolic and treadmill tests were performed and fat distribution was assessed using dual-energy x-ray absorptiometry. At baseline, month 3, and month 6, blood was collected for assay and cognitive tests were administered. Main Outcome Measures Performance measures on Symbol-Digit Modalities, Verbal Fluency, Stroop, Trails B, Task Switching, Story Recall, and List Learning. Fasting plasma levels of insulin, cortisol, brain-derived neurotrophic factor, insulinlike growth factor-I, and β-amyloids 40 and 42. Results Six months of high-intensity aerobic exercise had sex-specific effects on cognition, glucose metabolism, and hypothalamic-pituitary-adrenal axis and trophic activity despite comparable gains in cardiorespiratory fitness and body fat reduction. For women, aerobic exercise improved performance on multiple tests of executive function, increased glucose disposal during the metabolic clamp, and reduced fasting plasma levels of insulin, cortisol, and brain-derived neurotrophic factor. For men

The sweet trap in tumors: aerobic glycolysis and potential targets for therapy.

PubMed

Yu, Li; Chen, Xun; Wang, Liantang; Chen, Shangwu

2016-06-21

Metabolic change is one of the hallmarks of tumor, which has recently attracted a great of attention. One of main metabolic characteristics of tumor cells is the high level of glycolysis even in the presence of oxygen, known as aerobic glycolysis or the Warburg effect. The energy production is much less in glycolysis pathway than that in tricarboxylic acid cycle. The molecular mechanism of a high glycolytic flux in tumor cells remains unclear. A large amount of intermediates derived from glycolytic pathway could meet the biosynthetic requirements of the proliferating cells. Hypoxia-induced HIF-1α, PI3K-Akt-mTOR signaling pathway, and many other factors, such as oncogene activation and tumor suppressor inactivation, drive cancer cells to favor glycolysis over mitochondrial oxidation. Several small molecules targeting glycolytic pathway exhibit promising anticancer activity both in vitro and in vivo. In this review, we will focus on the latest progress in the regulation of aerobic glycolysis and discuss the potential targets for the tumor therapy.

Unique Flexibility in Energy Metabolism Allows Mycobacteria to Combat Starvation and Hypoxia

PubMed Central

Berney, Michael; Cook, Gregory M.

2010-01-01

Mycobacteria are a group of obligate aerobes that require oxygen for growth, but paradoxically have the ability to survive and metabolize under hypoxia. The mechanisms responsible for this metabolic plasticity are unknown. Here, we report on the adaptation of Mycobacterium smegmatis to slow growth rate and hypoxia using carbon-limited continuous culture. When M. smegmatis is switched from a 4.6 h to a 69 h doubling time at a constant oxygen saturation of 50%, the cells respond through the down regulation of respiratory chain components and the F1Fo-ATP synthase, consistent with the cells lower demand for energy at a reduced growth rate. This was paralleled by an up regulation of molecular machinery that allowed more efficient energy generation (i.e. Complex I) and the use of alternative electron donors (e.g. hydrogenases and primary dehydrogenases) to maintain the flow of reducing equivalents to the electron transport chain during conditions of severe energy limitation. A hydrogenase mutant showed a 40% reduction in growth yield highlighting the importance of this enzyme in adaptation to low energy supply. Slow growing cells at 50% oxygen saturation subjected to hypoxia (0.6% oxygen saturation) responded by switching on oxygen scavenging cytochrome bd, proton-translocating cytochrome bc1-aa3 supercomplex, another putative hydrogenase, and by substituting NAD+-dependent enzymes with ferredoxin-dependent enzymes thus highlighting a new pattern of mycobacterial adaptation to hypoxia. The expression of ferredoxins and a hydrogenase provides a potential conduit for disposing of and transferring electrons in the absence of exogenous electron acceptors. The use of ferredoxin-dependent enzymes would allow the cell to maintain a high carbon flux through its central carbon metabolism independent of the NAD+/NADH ratio. These data demonstrate the remarkable metabolic plasticity of the mycobacterial cell and provide a new framework for understanding their ability to survive

Aerobic fitness does not modulate protein metabolism in response to increased exercise: a controlled trial

USDA-ARS?s Scientific Manuscript database

Purpose: This study examined how a sudden increase in exercise energy expenditure affected whole body protein turnover and nitrogen balance in people of differing aerobic fitness. We hypothesized that whole-body protein turnover would be attenuated, and nitrogen balance would be preserved, in aerobi...

Proton motive force, energy recycling by end product excretion, and metabolic uncoupling during anaerobic growth of Pseudomonas mendocina.

PubMed Central

Verdoni, N; Aon, M A; Lebeault, J M; Thomas, D

1990-01-01

Batch cultures of Pseudomonas mendocina, grown in rich medium with glucose excess, showed metabolic differences dependent upon whether the growth conditions were aerobic or anaerobic, with or without added electron acceptor. Under anaerobic conditions in the absence of nitrate, P. mendocina reached the stationary phase of growth after 2 or 3 days, followed by a stationary phase of 4 to 5 days. Under these conditions, a mixed-type fermentative metabolism (formic, lactic, and acetic acids) appeared. A fivefold-higher specific rate of glucose consumption and eightfold-higher production of organic acids, compared with aerobic cultures, were shown by this microorganism growing anaerobically in the absence of exogenous electron acceptors. The gradients of organic acid produced by P. mendocina under these conditions reached a maximum (lactate, 180 mV; formate, 150 mV; acetate, 215 mV) between days 2 and 3 of culture. The proton motive force (delta p) decreased during growth from -254 to -71 mV. The intracellular pH remained alkaline during the culture, reaching a steady-state value of 7.9. The gradients of organic acids apparently contributed to the generation of a delta p, which, according to the Energy Recycling Model (P. A. M. Michels, J. P. J. Michels, J. Boonstra, and W. N. Konings, FEMS Microbiol. Lett. 5:357-364, 1979), would produce an average energy gain of 1 or 1.5 mol of ATP equivalents per mol of glucose consumed with H+/ATP stoichiometry of 3 or 2, respectively. Low YATP and Yglucose values were observed, suggesting that an uncoupled metabolism exists; i.e., ATP produced by catabolic processes is not directly used for biomass synthesis. This metabolic uncoupling could be induced at least in part by organic acids and the ATP wastage could be induced by a membrane-bound ATPase involved in intracellular pH regulation. PMID:2254245

Introduction to the molecular basis of cancer metabolism and the Warburg effect.

PubMed

Ngo, Darleen C; Ververis, Katherine; Tortorella, Stephanie M; Karagiannis, Tom C

2015-04-01

In differentiated normal cells, the conventional route of glucose metabolism involves glycolysis, followed by the citric acid cycle and electron transport chain to generate usable energy in the form of adenosine triphosphate (ATP). This occurs in the presence of oxygen. In hypoxic conditions, normal cells undergo anaerobic glycolysis to yield significantly less energy producing lactate as a product. As first highlighted in the 1920s by Otto Warburg, the metabolism exhibited by tumor cells involves an increased rate of aerobic glycolysis, known as the Warburg effect. In aerobic glycolysis, pyruvate molecules yielded from glycolysis are converted into fewer molecules of ATP even in the presence of oxygen. Evidence indicates that the reasons as to why tumor cells undergo aerobic glycolysis include: (1) the shift in priority to accumulate biomass rather than energy production, (2) the evasion of apoptosis as fewer reactive oxygen species are released by the mitochondria and (3) the production of lactate to further fuel growth of tumors. In this mini-review we discuss emerging molecular aspects of cancer metabolism and the Warburg effect. Aspects of the Warburg effect are analyzed in the context of the established hallmarks of cancer including the role of oncogenes and tumor suppressor genes.

Aerobic Exercise, Estrogens, and Breast Cancer Risk

DTIC Science & Technology

2011-11-01

on endogenous sex hormone levels, menstrual cycle characteristics, and estrogen metabolism in sedentary, eumenorrheic, healthy premenopausal women...changes in menstrual cycle length, and 4) limited changes in estrogen metabolism. The resulting increases in urinary 2-hydroxyestrone levels and 2...effects of a 16-week, aerobic exercise intervention on endogenous sex hormone levels, menstrual cycle characteristics, and estrogen metabolism of young

Energy Metabolism Impairment in Migraine.

PubMed

Cevoli, Sabina; Favoni, Valentina; Cortelli, Pietro

2018-06-22

Migraine is a common disabling neurological disorder which is characterised by recurring headache associated with a variety of sensory and autonomic symptoms. The pathophysiology of migraine remains not entirely understood, although many mechanisms involving the central and peripheral nervous system are now becoming clear. In particular, it is widely accepted that migraine is associated with energy metabolic impairment of the brain. The purpose of this review is to present an update overview of the energy metabolism involvement in the migraine pathophysiology. Several biochemical, morphological and magnetic resonance spectroscopy studies have confirmed the presence of energy production deficiency together with an increment of energy consumption in migraine patients. An increment of energy demand over a certain threshold create metabolic and biochemical preconditions for the onset of the migraine attack. The defect of oxidative energy metabolism in migraine is generalized. It remains to be determined if the mitochondrial deficit in migraine is primary or secondary. Riboflavin and Co-Enzyme Q10, both physiologically implicated in mitochondrial respiratory chain functioning, are effective in migraine prophylaxis, supporting the hypothesis that improving brain energy metabolism may reduce the susceptibility to migraine. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Reprogramming of Escherichia coli K-12 metabolism during the initial phase of transition from an anaerobic to a micro-aerobic environment.

PubMed

Trotter, Eleanor W; Rolfe, Matthew D; Hounslow, Andrea M; Craven, C Jeremy; Williamson, Michael P; Sanguinetti, Guido; Poole, Robert K; Green, Jeffrey

2011-01-01

Many bacteria undergo transitions between environments with differing O₂ availabilities as part of their natural lifestyles and during biotechnological processes. However, the dynamics of adaptation when bacteria experience changes in O₂ availability are understudied. The model bacterium and facultative anaerobe Escherichia coli K-12 provides an ideal system for exploring this process. Time-resolved transcript profiles of E. coli K-12 during the initial phase of transition from anaerobic to micro-aerobic conditions revealed a reprogramming of gene expression consistent with a switch from fermentative to respiratory metabolism. The changes in transcript abundance were matched by changes in the abundances of selected central metabolic proteins. A probabilistic state space model was used to infer the activities of two key regulators, FNR (O₂ sensing) and PdhR (pyruvate sensing). The model implied that both regulators were rapidly inactivated during the transition from an anaerobic to a micro-aerobic environment. Analysis of the external metabolome and protein levels suggested that the cultures transit through different physiological states during the process of adaptation, characterized by the rapid inactivation of pyruvate formate-lyase (PFL), a slower induction of pyruvate dehydrogenase complex (PDHC) activity and transient excretion of pyruvate, consistent with the predicted inactivation of PdhR and FNR. Perturbation of anaerobic steady-state cultures by introduction of a limited supply of O₂ combined with time-resolved transcript, protein and metabolite profiling, and probabilistic modeling has revealed that pyruvate (sensed by PdhR) is a key metabolic signal in coordinating the reprogramming of E. coli K-12 gene expression by working alongside the O₂ sensor FNR during transition from anaerobic to micro-aerobic conditions.

The role of sulfate in aerobic granular sludge process for emerging sulfate-laden wastewater treatment.

PubMed

Xue, Weiqi; Hao, Tianwei; Mackey, Hamish R; Li, Xiling; Chan, Richard C; Chen, Guanghao

2017-11-01

Sulfate-rich wastewaters pose a major threat to mainstream wastewater treatment due to the unpreventable production of sulfide and associated shift in functional bacteria. Aerobic granular sludge could mitigate these challenges in view of its high tolerance and resilience against changes in various environmental conditions. This study aims to confirm the feasibility of aerobic granular sludge in the treatment of sulfate containing wastewater, investigate the impact of sulfate on nutrient removal and granulation, and reveal metabolic relationships in the above processes. Experiments were conducted using five sequencing batch reactors with different sulfate concentrations operated under alternating anoxic/aerobic condition. Results showed that effect of sulfate on chemical oxygen demand (COD) removal is negligible, while phosphate removal was enhanced from 12% to 87% with an increase in sulfate from 0 to 200 mg/L. However, a long acclimatization of the biomass (more than 70 days) is needed at a sulfate concentration of 500 mg/L and a total deterioration of phosphate removal at 1000 mg/L. Batch tests revealed that sulfide promoted volatile fatty acids (VFAs) uptake, producing more energy for phosphate uptake when sulfate concentrations were beneath 200 mg/L. However, sulfide detoxification became energy dominating, leaving insufficient energy for Polyhydroxyalkanoate (PHA) synthesis and phosphate uptake when sulfate content was further increased. Granulation accelerated with increasing sulfate levels by enhanced production of N-Acyl homoserine lactones (AHLs), a kind of quorum sensing (QS) auto-inducer, using S-Adenosyl Methionine (SAM) as primer. The current study demonstrates interactions among sulfate metabolism, nutrients removal and granulation, and confirms the feasibility of using the aerobic granular sludge process for sulfate-laden wastewaters treatment with low to medium sulfate content. Copyright © 2017 Elsevier Ltd. All rights reserved.

Dose–response effects of aerobic exercise on energy compensation in postmenopausal women: combined results from two randomized controlled trials

PubMed Central

McNeil, J; Brenner, D R; Courneya, K S; Friedenreich, C M

2017-01-01

Background/objectives: Despite the clear health benefits of exercise, exercised-induced weight loss is often less than expected. The term ‘exercise energy compensation’ is used to define the amount of weight loss below what is expected for the amount of exercise energy expenditure. We examined the dose–response effects of exercise volume on energy compensation in postmenopausal women. Participants/methods: Data from Alberta Physical Activity and Breast Cancer Prevention (ALPHA) and Breast Cancer and Exercise Trial in Alberta (BETA) were combined for the present analysis. The ALPHA and BETA trials were two-centred, two-armed, 12-month randomized controlled trials. The ALPHA trial included 160 participants randomized to 225 min per week of aerobic exercise, and the BETA trial randomized 200 participants to each 150 and 300 min per week of aerobic exercise. All participants were aged 50–74 years, moderately inactive (<90 min per week of exercise), had no previous cancer diagnosis and a body mass index between 22 and 40 kg m−2. Energy compensation was based on changes in body composition (dual-energy X-ray absorptiometry scan) and estimated exercise energy expenditure from completed exercise volume. Associations between Δenergy intake, ΔVO2peak and Δphysical activity time with energy compensation were assessed. Results: No differences in energy compensation were noted between interventions. However, there were large inter-individual differences in energy compensation between participants; 9.4% experienced body composition changes that were greater than expected based on exercise energy expenditure, 64% experienced some degree of energy compensation and 26.6% experienced weight gain based on exercise energy expenditure. Increases in VO2peak were associated with reductions in energy compensation (β=−3.44 ml kg−1 min−1, 95% confidence interval for β=−4.71 to −2.17 ml kg−1 min−1; P=0.0001). Conclusions: Large inter

Dose-response effects of aerobic exercise on energy compensation in postmenopausal women: combined results from two randomized controlled trials.

PubMed

McNeil, J; Brenner, D R; Courneya, K S; Friedenreich, C M

2017-08-01

Despite the clear health benefits of exercise, exercised-induced weight loss is often less than expected. The term 'exercise energy compensation' is used to define the amount of weight loss below what is expected for the amount of exercise energy expenditure. We examined the dose-response effects of exercise volume on energy compensation in postmenopausal women. Data from Alberta Physical Activity and Breast Cancer Prevention (ALPHA) and Breast Cancer and Exercise Trial in Alberta (BETA) were combined for the present analysis. The ALPHA and BETA trials were two-centred, two-armed, 12-month randomized controlled trials. The ALPHA trial included 160 participants randomized to 225 min per week of aerobic exercise, and the BETA trial randomized 200 participants to each 150 and 300 min per week of aerobic exercise. All participants were aged 50-74 years, moderately inactive (<90 min per week of exercise), had no previous cancer diagnosis and a body mass index between 22 and 40 kg m -2 . Energy compensation was based on changes in body composition (dual-energy X-ray absorptiometry scan) and estimated exercise energy expenditure from completed exercise volume. Associations between Δenergy intake, ΔVO 2peak and Δphysical activity time with energy compensation were assessed. No differences in energy compensation were noted between interventions. However, there were large inter-individual differences in energy compensation between participants; 9.4% experienced body composition changes that were greater than expected based on exercise energy expenditure, 64% experienced some degree of energy compensation and 26.6% experienced weight gain based on exercise energy expenditure. Increases in VO 2peak were associated with reductions in energy compensation (β=-3.44 ml kg -1  min -1 , 95% confidence interval for β=-4.71 to -2.17 ml kg -1  min -1 ; P=0.0001). Large inter-individual differences in energy compensation were noted, despite no differences

Exercise training in the aerobic/anaerobic metabolic transition prevents glucose intolerance in alloxan-treated rats.

PubMed

Soares de Alencar Mota, Clécia; Ribeiro, Carla; de Araújo, Gustavo Gomes; de Araújo, Michel Barbosa; de Barros Manchado-Gobatto, Fúlvia; Voltarelli, Fabrício Azevedo; de Oliveira, Camila Aparecida Machado; Luciano, Eliete; de Mello, Maria Alice Rostom

2008-10-02

Ninety percent of cases of diabetes are of the slowly evolving non-insulin-dependent type, or Type 2 diabetes. Lack of exercise is regarded as one of the main causes of this disorder. In this study we analyzed the effects of physical exercise on glucose homeostasis in adult rats with type 2 diabetes induced by a neonatal injection of alloxan. Female Wistar rats aged 6 days were injected with either 250 mg/kg of body weight of alloxan or citrate buffer 0.01 M (controls). After weaning, half of the animals in each group were subjected to physical training adjusted to meet the aerobic-anaerobic metabolic transition by swimming 1 h/day for 5 days a week with weight overloads. The necessary overload used was set and periodically readjusted for each rat through effort tests based on the maximal lactate steady state procedure. When aged 28, 60, 90, and 120 days, the rats underwent glucose tolerance tests (GTT) and their peripheral insulin sensitivity was evaluated using the HOMA index. The area under the serum glucose curve obtained through GTT was always higher in alloxan-treated animals than in controls. A decrease in this area was observed in trained alloxan-treated rats at 90 and 120 days old compared with non-trained animals. At 90 days old the trained controls showed lower HOMA indices than the non-trained controls. Neonatal administration of alloxan induced a persistent glucose intolerance in all injected rats, which was successfully counteracted by physical training in the aerobic/anaerobic metabolic transition.

Effects of Simultaneous or Sequential Weight Loss Diet and Aerobic Interval Training on Metabolic Syndrome.

PubMed

Mora-Rodriguez, R; Ortega, J F; Guio de Prada, V; Fernández-Elías, V E; Hamouti, N; Morales-Palomo, F; Martinez-Vizcaino, V; Nelson, R K

2016-04-01

Our purpose in this study was to investigate efficient and sustainable combinations of exercise and diet-induced weight loss (DIET), in order to combat obesity in metabolic syndrome (MetS) patients. We examined the impact of aerobic interval training (AIT), followed by or concurrent to a DIET on MetS components. 36 MetS patients (54±9 years old; 33±4 BMI; 27 males and 9 females) underwent 16 weeks of AIT followed by another 16 weeks without exercise from the fall of 2013 to the spring of 2014. Participants were randomized to AIT without DIET (E CON, n=12), AIT followed by DIET (E-then-D, n=12) or AIT concurrent with DIET (E+D, n=12) groups. Body weight decreased below E CON similarly in the E-then-D and E+D groups (~5%). Training improved blood pressure and cardiorespiratory fitness (VO2peak) in all groups with no additional effect of concurrent weight loss. However, E+D improved insulin sensitivity (HOMA) and lowered plasma triglycerides and blood cholesterol below E CON and E-then-D (all P<0.05). Weight loss in E-then-D in the 16 weeks without exercise lowered HOMA to the E+D levels and maintained blood pressure at trained levels. Our data suggest that a new lifestyle combination consisting of aerobic interval training followed by weight loss diet is similar, or even more effective on improving metabolic syndrome factors than concurrent exercise plus diet. © Georg Thieme Verlag KG Stuttgart · New York.

Effects of Aerobic Training on Cognition and Brain Glucose Metabolism in Subjects with Mild Cognitive Impairment.

PubMed

Porto, Fábio Henrique de Gobbi; Coutinho, Artur Martins Novaes; Pinto, Ana Lucia de Sá; Gualano, Bruno; Duran, Fabio Luís de Souza; Prando, Silvana; Ono, Carla Rachel; Spíndola, Lívia; de Oliveira, Maira Okada; do Vale, Patrícia Helena Figuerêdo; Nitrini, Ricardo; Buchpiguel, Carlos Alberto; Brucki, Sonia Maria Dozzi

2015-01-01

Aerobic training (AT) is a promising intervention for mild cognitive impairment (MCI). To evaluate the effects of AT on cognition and regional brain glucose metabolism (rBGM) in MCI patients. Subjects performed a twice-a-week, moderate intensity, AT program for 24 weeks. Assessment with ADAS-cog, a comprehensive neuropsychological battery, and evaluation of rBGM with positron emission tomography with 18F-fluorodeoxyglucose ([18F]FDG-PET) were performed before and after the intervention. Aerobic capacity was compared using the maximal oxygen consumption VO2max (mL/Kg/min). [18F]FDG-PET data were analyzed on a voxel-by-voxel basis with SPM8 software. Forty subjects were included, with a mean (M) age of 70.3 (5.4) years and an initial Mini-Mental State Exam score of 27.4 (1.7). Comparisons using paired t-tests revealed improvements in the ADAS-cog (M difference: -2.7 (3.7), p <  0.001) and VO2max scores (M difference: 1.8 (2.0) mL/kg/min, p <  0.001). Brain metabolic analysis revealed a bilateral decrease in the rBGM of the dorsal anterior cingulate cortex, pFWE = 0.04. This rBGM decrease was negatively correlated with improvement in a visuospatial function/attentional test (rho =-0.31, p = 0.04). Several other brain areas also showed increases or decreases in rBGM. Of note, there was an increase in the retrosplenial cortex, an important node of the default mode network, that was negatively correlated with the metabolic decrease in the dorsal anterior cingulate cortex (r =-0.51, p = 0.001). AT improved cognition and changed rBGM in areas related to cognition in subjects with MCI.

The marine mammal dive response is exercise modulated to maximize aerobic dive duration.

PubMed

Davis, Randall W; Williams, Terrie M

2012-08-01

When aquatically adapted mammals and birds swim submerged, they exhibit a dive response in which breathing ceases, heart rate slows, and blood flow to peripheral tissues and organs is reduced. The most intense dive response occurs during forced submersion which conserves blood oxygen for the brain and heart, thereby preventing asphyxiation. In free-diving animals, the dive response is less profound, and energy metabolism remains aerobic. However, even this relatively moderate bradycardia seems diametrically opposed to the normal cardiovascular response (i.e., tachycardia and peripheral vasodilation) during physical exertion. As a result, there has been a long-standing paradox regarding how aquatic mammals and birds exercise while submerged. We hypothesized based on cardiovascular modeling that heart rate must increase to ensure adequate oxygen delivery to active muscles. Here, we show that heart rate (HR) does indeed increase with flipper or fluke stroke frequency (SF) during voluntary, aerobic dives in Weddell seals (HR = 1.48SF - 8.87) and bottlenose dolphins (HR = 0.99SF + 2.46), respectively, two marine mammal species with different evolutionary lineages. These results support our hypothesis that marine mammals maintain aerobic muscle metabolism while swimming submerged by combining elements of both dive and exercise responses, with one or the other predominating depending on the level of exertion.

Reprogramming of Escherichia coli K-12 Metabolism during the Initial Phase of Transition from an Anaerobic to a Micro-Aerobic Environment

PubMed Central

Trotter, Eleanor W.; Rolfe, Matthew D.; Hounslow, Andrea M.; Craven, C. Jeremy; Williamson, Michael P.; Sanguinetti, Guido; Poole, Robert K.; Green, Jeffrey

2011-01-01

Background Many bacteria undergo transitions between environments with differing O2 availabilities as part of their natural lifestyles and during biotechnological processes. However, the dynamics of adaptation when bacteria experience changes in O2 availability are understudied. The model bacterium and facultative anaerobe Escherichia coli K-12 provides an ideal system for exploring this process. Methods and Findings Time-resolved transcript profiles of E. coli K-12 during the initial phase of transition from anaerobic to micro-aerobic conditions revealed a reprogramming of gene expression consistent with a switch from fermentative to respiratory metabolism. The changes in transcript abundance were matched by changes in the abundances of selected central metabolic proteins. A probabilistic state space model was used to infer the activities of two key regulators, FNR (O2 sensing) and PdhR (pyruvate sensing). The model implied that both regulators were rapidly inactivated during the transition from an anaerobic to a micro-aerobic environment. Analysis of the external metabolome and protein levels suggested that the cultures transit through different physiological states during the process of adaptation, characterized by the rapid inactivation of pyruvate formate-lyase (PFL), a slower induction of pyruvate dehydrogenase complex (PDHC) activity and transient excretion of pyruvate, consistent with the predicted inactivation of PdhR and FNR. Conclusion Perturbation of anaerobic steady-state cultures by introduction of a limited supply of O2 combined with time-resolved transcript, protein and metabolite profiling, and probabilistic modeling has revealed that pyruvate (sensed by PdhR) is a key metabolic signal in coordinating the reprogramming of E. coli K-12 gene expression by working alongside the O2 sensor FNR during transition from anaerobic to micro-aerobic conditions. PMID:21980479

Metabolism of 2-Chloro-4-Nitroaniline via Novel Aerobic Degradation Pathway by Rhodococcus sp. Strain MB-P1

PubMed Central

Khan, Fazlurrahman; Pal, Deepika; Vikram, Surendra; Cameotra, Swaranjit Singh

2013-01-01

2-chloro-4-nitroaniline (2-C-4-NA) is used as an intermediate in the manufacture of dyes, pharmaceuticals, corrosion inhibitor and also used in the synthesis of niclosamide, a molluscicide. It is marked as a black-listed substance due to its poor biodegradability. We report biodegradation of 2-C-4-NA and its pathway characterization by Rhodococcus sp. strain MB-P1 under aerobic conditions. The strain MB-P1 utilizes 2-C-4-NA as the sole carbon, nitrogen, and energy source. In the growth medium, the degradation of 2-C-4-NA occurs with the release of nitrite ions, chloride ions, and ammonia. During the resting cell studies, the 2-C-4-NA-induced cells of strain MB-P1 transformed 2-C-4-NA stoichiometrically to 4-amino-3-chlorophenol (4-A-3-CP), which subsequently gets transformed to 6-chlorohydroxyquinol (6-CHQ) metabolite. Enzyme assays by cell-free lysates prepared from 2-C-4-NA-induced MB-P1 cells, demonstrated that the first enzyme in the 2-C-4-NA degradation pathway is a flavin-dependent monooxygenase that catalyzes the stoichiometric removal of nitro group and production of 4-A-3-CP. Oxygen uptake studies on 4-A-3-CP and related anilines by 2-C-4-NA-induced MB-P1 cells demonstrated the involvement of aniline dioxygenase in the second step of 2-C-4-NA degradation. This is the first report showing 2-C-4-NA degradation and elucidation of corresponding metabolic pathway by an aerobic bacterium. PMID:23614030

Posttranscriptional Control of T Cell Effector Function by Aerobic Glycolysis

PubMed Central

Chang, Chih-Hao; Curtis, Jonathan D.; Maggi, Leonard B.; Faubert, Brandon; Villarino, Alejandro V.; O’Sullivan, David; Huang, Stanley Ching-Cheng; van der Windt, Gerritje J.W.; Blagih, Julianna; Qiu, Jing; Weber, Jason D.; Pearce, Edward J.; Jones, Russell G.; Pearce, Erika L.

2013-01-01

SUMMARY A “switch” from oxidative phosphorylation (OXPHOS) to aerobic glycolysis is a hallmark of T cell activation and is thought to be required to meet the metabolic demands of proliferation. However, why proliferating cells adopt this less efficient metabolism, especially in an oxygen-replete environment, remains incompletely understood. We show here that aerobic glycolysis is specifically required for effector function in T cells but that this pathway is not necessary for proliferation or survival. When activated T cells are provided with costimulation and growth factors but are blocked from engaging glycolysis, their ability to produce IFN-γ is markedly compromised. This defect is translational and is regulated by the binding of the glycolysis enzyme GAPDH to AU-rich elements within the 3′ UTR of IFN-γ mRNA. GAPDH, by engaging/disengaging glycolysis and through fluctuations in its expression, controls effector cytokine production. Thus, aerobic glycolysis is a metabolically regulated signaling mechanism needed to control cellular function. PMID:23746840

Effects of aerobic exercise on mild cognitive impairment: a controlled trial.

PubMed

Baker, Laura D; Frank, Laura L; Foster-Schubert, Karen; Green, Pattie S; Wilkinson, Charles W; McTiernan, Anne; Plymate, Stephen R; Fishel, Mark A; Watson, G Stennis; Cholerton, Brenna A; Duncan, Glen E; Mehta, Pankaj D; Craft, Suzanne

2010-01-01

To examine the effects of aerobic exercise on cognition and other biomarkers associated with Alzheimer disease pathology for older adults with mild cognitive impairment, and assess the role of sex as a predictor of response. Six-month, randomized, controlled, clinical trial. Veterans Affairs Puget Sound Health Care System clinical research unit. Thirty-three adults (17 women) with amnestic mild cognitive impairment ranging in age from 55 to 85 years (mean age, 70 years). Intervention Participants were randomized either to a high-intensity aerobic exercise or stretching control group. The aerobic group exercised under the supervision of a fitness trainer at 75% to 85% of heart rate reserve for 45 to 60 min/d, 4 d/wk for 6 months. The control group carried out supervised stretching activities according to the same schedule but maintained their heart rate at or below 50% of their heart rate reserve. Before and after the study, glucometabolic and treadmill tests were performed and fat distribution was assessed using dual-energy x-ray absorptiometry. At baseline, month 3, and month 6, blood was collected for assay and cognitive tests were administered. Performance measures on Symbol-Digit Modalities, Verbal Fluency, Stroop, Trails B, Task Switching, Story Recall, and List Learning. Fasting plasma levels of insulin, cortisol, brain-derived neurotrophic factor, insulinlike growth factor-I, and beta-amyloids 40 and 42. Six months of high-intensity aerobic exercise had sex-specific effects on cognition, glucose metabolism, and hypothalamic-pituitary-adrenal axis and trophic activity despite comparable gains in cardiorespiratory fitness and body fat reduction. For women, aerobic exercise improved performance on multiple tests of executive function, increased glucose disposal during the metabolic clamp, and reduced fasting plasma levels of insulin, cortisol, and brain-derived neurotrophic factor. For men, aerobic exercise increased plasma levels of insulinlike growth factor I

Effects of a low- or a high-carbohydrate diet on performance, energy system contribution, and metabolic responses during supramaximal exercise.

PubMed

Lima-Silva, Adriano E; Pires, Flavio O; Bertuzzi, Romulo; Silva-Cavalcante, Marcos D; Oliveira, Rodrigo S F; Kiss, Maria Augusta; Bishop, David

2013-09-01

The purpose of the present study was to examine the effects of a high- or low-carbohydrate (CHO) diet on performance, aerobic and anaerobic contribution, and metabolic responses during supramaximal exercise. Six physically-active men first performed a cycling exercise bout at 115% maximal oxygen uptake to exhaustion after following their normal diet for 48 h (∼50% of CHO, control test). Seventy-two hours after, participants performed a muscle glycogen depletion exercise protocol, followed by either a high- or low-CHO diet (∼70 and 25% of CHO, respectively) for 48 h, in a random, counterbalanced order. After the assigned diet period (48 h), the supramaximal cycling exercise bout (115% maximal oxygen consumption) to exhaustion was repeated. The low-CHO diet reduced time to exhaustion when compared with both the control and the high-CHO diet (-19 and -32%, respectively, p < 0.05). The reduced time to exhaustion following the low-CHO diet was accompanied by a lower total aerobic energy contribution (-39%) compared with the high-CHO diet (p < 0.05). However, the aerobic and anaerobic energy contribution at the shortest time to exhaustion (isotime) was similar among conditions (p > 0.05). The low-CHO diet was associated with a lower blood lactate concentration (p < 0.05), with no effect on the plasma concentration of insulin, glucose and K(+) (p > 0.05). In conclusion, a low-CHO diet reduces both performance and total aerobic energy provision during supramaximal exercise. As peak K(+) concentration was similar, but time to exhaustion shorter, the low-CHO diet was associated with an earlier attainment of peak plasma K(+) concentration.

Metabolic crosstalk between choline/1-carbon metabolism and energy homeostasis

PubMed Central

Zeisel, Steven H.

2013-01-01

There are multiple identified mechanisms involved in energy metabolism, insulin resistance and adiposity, but there are here-to-fore unsuspected metabolic factors that also influence these processes. Studies in animal models suggest important links between choline/1-carbon metabolism and energy homeostasis. Rodents fed choline deficient diets become hypermetabolic. Mice with deletions in one of several different genes of choline metabolism have phenotypes that include increased metabolic rate, decreased body fat/lean mass ratio, increased insulin sensitivity, decreased ATP production by mitochondria, or decreased weight gain on a high fat diet. In addition, farmers have recognized that the addition of a metabolite of choline (betaine) to cattle and swine feed reduces body fat/lean mass ratio. Choline dietary intake in humans varies over a >three-fold range, and genetic variation exists that modifies individual requirements for this nutrient. Although there are some epidemiologic studies in humans suggesting a link between choline/1-carbon metabolism and energy metabolism, there have been no controlled studies in humans that were specifically designed to examine this relationship. PMID:23072856

The sweet trap in tumors: aerobic glycolysis and potential targets for therapy

PubMed Central

Wang, Liantang; Chen, Shangwu

2016-01-01

Metabolic change is one of the hallmarks of tumor, which has recently attracted a great of attention. One of main metabolic characteristics of tumor cells is the high level of glycolysis even in the presence of oxygen, known as aerobic glycolysis or the Warburg effect. The energy production is much less in glycolysis pathway than that in tricarboxylic acid cycle. The molecular mechanism of a high glycolytic flux in tumor cells remains unclear. A large amount of intermediates derived from glycolytic pathway could meet the biosynthetic requirements of the proliferating cells. Hypoxia-induced HIF-1α, PI3K-Akt-mTOR signaling pathway, and many other factors, such as oncogene activation and tumor suppressor inactivation, drive cancer cells to favor glycolysis over mitochondrial oxidation. Several small molecules targeting glycolytic pathway exhibit promising anticancer activity both in vitro and in vivo. In this review, we will focus on the latest progress in the regulation of aerobic glycolysis and discuss the potential targets for the tumor therapy. PMID:26918353

Aerobic exercise increases peripheral and hepatic insulin sensitivity in sedentary adolescents

USDA-ARS?s Scientific Manuscript database

Data are limited on the effects of controlled aerobic exercise programs (without weight loss) on insulin sensitivity and glucose metabolism in children and adolescents. To determine whether a controlled aerobic exercise program (without weight loss) improves peripheral and hepatic insulin sensitivi...

Effects of Aerobic and Resistance Exercise on Metabolic Syndrome, Sarcopenic Obesity, and Circulating Biomarkers in Overweight or Obese Survivors of Breast Cancer: A Randomized Controlled Trial.

PubMed

Dieli-Conwright, Christina M; Courneya, Kerry S; Demark-Wahnefried, Wendy; Sami, Nathalie; Lee, Kyuwan; Buchanan, Thomas A; Spicer, Darcy V; Tripathy, Debu; Bernstein, Leslie; Mortimer, Joanne E

2018-03-20

Purpose Metabolic syndrome is associated with an increased risk of cardiovascular disease, type 2 diabetes, and breast cancer recurrence in survivors of breast cancer. This randomized controlled trial assessed the effects of a 16-week combined aerobic and resistance exercise intervention on metabolic syndrome, sarcopenic obesity, and serum biomarkers among ethnically diverse, sedentary, overweight, or obese survivors of breast cancer. Methods Eligible survivors of breast cancer (N = 100) were randomly assigned to exercise (n = 50) or usual care (n = 50). The exercise group participated in supervised moderate-to-vigorous-65% to 85% of heart rate maximum-aerobic and resistance exercise three times per week for 16 weeks. Metabolic syndrome z-score (primary outcome), sarcopenic obesity, and serum biomarkers were measured at baseline, postintervention (4 months), and 3-month follow-up (exercise only). Results Participants were age 53 ± 10.4 years, 46% were obese, and 74% were ethnic minorities. Adherence to the intervention was 95%, and postintervention assessments were available in 91% of participants. Postintervention metabolic syndrome z-score was significantly improved in exercise versus usual care (between-group difference, -4.4; 95% CI, -5.9 to -2.7; P < .001). Sarcopenic obesity (appendicular skeletal mass index, P = .001; body mass index, P = .001) and circulating biomarkers, including insulin ( P = .002), IGF-1 ( P = .001), leptin ( P = .001), and adiponectin ( P = .001), were significantly improved postintervention compared with usual care. At 3-month follow-up, all metabolic syndrome variables remained significantly improved compared with baseline in the exercise group ( P < .01). Conclusion Combined resistance and aerobic exercise effectively attenuated metabolic syndrome, sarcopenic obesity, and relevant biomarkers in an ethnically diverse sample of sedentary, overweight, or obese survivors of breast cancer. Our findings suggest a targeted exercise

TRPV1 activation improves exercise endurance and energy metabolism through PGC-1α upregulation in mice.

PubMed

Luo, Zhidan; Ma, Liqun; Zhao, Zhigang; He, Hongbo; Yang, Dachun; Feng, Xiaoli; Ma, Shuangtao; Chen, Xiaoping; Zhu, Tianqi; Cao, Tingbing; Liu, Daoyan; Nilius, Bernd; Huang, Yu; Yan, Zhencheng; Zhu, Zhiming

2012-03-01

Impaired aerobic exercise capacity and skeletal muscle dysfunction are associated with cardiometabolic diseases. Acute administration of capsaicin enhances exercise endurance in rodents, but the long-term effect of dietary capsaicin is unknown. The capsaicin receptor, the transient receptor potential vanilloid 1 (TRPV1) cation channel has been detected in skeletal muscle, the role of which remains unclear. Here we report the function of TRPV1 in cultured C2C12 myocytes and the effect of TRPV1 activation by dietary capsaicin on energy metabolism and exercise endurance of skeletal muscles in mice. In vitro, capsaicin increased cytosolic free calcium and peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) expression in C2C12 myotubes through activating TRPV1. In vivo, PGC-1α in skeletal muscle was upregulated by capsaicin-induced TRPV1 activation or genetic overexpression of TRPV1 in mice. TRPV1 activation increased the expression of genes involved in fatty acid oxidation and mitochondrial respiration, promoted mitochondrial biogenesis, increased oxidative fibers, enhanced exercise endurance and prevented high-fat diet-induced metabolic disorders. Importantly, these effects of capsaicin were absent in TRPV1-deficient mice. We conclude that TRPV1 activation by dietary capsaicin improves energy metabolism and exercise endurance by upregulating PGC-1α in skeletal muscles. The present results indicate a novel therapeutic strategy for managing metabolic diseases and improving exercise endurance.

Aerobic power, huddling and the efficiency of torpor in the South American marsupial, Dromiciops gliroides

PubMed Central

Franco, Marcela; Contreras, Carolina; Cortés, Pablo; Chappell, Mark A.; Soto-Gamboa, Mauricio; Nespolo, Roberto F.

2012-01-01

Summary During periods of cold, small endotherms depend on a continuous supply of food and energy to maintain euthermic body temperature (Tb), which can be challenging if food is limited. In these conditions, energy-saving strategies are critical to reduce the energetic requirements for survival. Mammals from temperate regions show a wide arrange of such strategies, including torpor and huddling. Here we provide a quantitative description of thermoregulatory capacities and energy-saving strategies in Dromiciops gliroides, a Microbiotherid marsupial inhabiting temperate rain forests. Unlike many mammals from temperate regions, preliminary studies have suggested that this species has low capacity for control and regulation of body temperature, but there is still an incomplete picture of its bioenergetics. In order to more fully understand the physiological capacities of this “living fossil”, we measured its scope of aerobic power and the interaction between huddling and torpor. Specifically, we evaluated: (1) the relation between basal (BMR) and maximum metabolic rate (MMR), and (2) the role of huddling on the characteristics of torpor at different temperatures. We found that BMR and MMR were above the expected values for marsupials and the factorial aerobic scope (from CO2) was 6.0±0.45 (using CO2) and 6.2±0.23 (using O2), an unusually low value for mammals. Also, repeatability of physiological variables was non-significant, as in previous studies, suggesting poor time-consistency of energy metabolism. Comparisons of energy expenditure and body temperature (using attached data-loggers) between grouped and isolated individuals showed that at 20°C both average resting metabolic rate and body temperature were higher in groups, essentially because animals remained non-torpid. At 10°C, however, all individuals became torpid and no differences were observed between grouped and isolated individuals. In summary, our study suggests that the main response of

The Individual, Joint, and Additive Interaction Associations of Aerobic-Based Physical Activity and Muscle Strengthening Activities on Metabolic Syndrome.

PubMed

Dankel, Scott J; Loenneke, Jeremy P; Loprinzi, Paul D

2016-12-01

Previous research has demonstrated that physical activity and muscle strengthening activities are independently and inversely associated with metabolic syndrome. Despite a number of studies examining the individual associations, only a few studies have examined the joint associations, and to our knowledge, no previous studies have examined the potential additive interaction of performing muscle strengthening activities and aerobic-based physical activity and their association with metabolic syndrome. Using data from the 2003 to 2006 National Health and Nutrition Examination Survey (NHANES), we computed three separate multivariable logistic regression models to examine the individual, combined, and additive interaction of meeting guidelines for accelerometer-assessed physical activity and self-reported muscle strengthening activities, and their association with metabolic syndrome. We found that individuals meeting physical activity and muscle strengthening activity guidelines, respectively, were at 61 and 25 % lower odds of having metabolic syndrome. Furthermore, individuals meeting both guidelines had the lowest odds of having metabolic syndrome (70 %), in part due to the additive interaction of performing both modes of exercise. In this national sample, accelerometer-assessed physical activity and muscle strengthening activities were synergistically associated with metabolic syndrome.

Three different [NiFe] hydrogenases confer metabolic flexibility in the obligate aerobe Mycobacterium smegmatis.

PubMed

Berney, Michael; Greening, Chris; Hards, Kiel; Collins, Desmond; Cook, Gregory M

2014-01-01

Mycobacterium smegmatis is an obligate aerobe that harbours three predicted [NiFe] hydrogenases, Hyd1 (MSMEG_2262–2263), Hyd2 (MSMEG_2720-2719) and Hyd3 (MSMEG_3931-3928). We show here that these three enzymes differ in their phylogeny, regulation and catalytic activity. Phylogenetic analysis revealed that Hyd1 groups with hydrogenases that oxidize H2 produced by metabolic processes, and Hyd2 is homologous to a novel group of putative high-affinity hydrogenases. Hyd1 and Hyd2 respond to carbon and oxygen limitation, and, in the case of Hyd1, hydrogen supplementation. Hydrogen consumption measurements confirmed that both enzymes can oxidize hydrogen. In contrast, the phylogenetic analysis and activity measurements of Hyd3 are consistent with the enzyme evolving hydrogen. Hyd3 is controlled by DosR, a regulator that responds to hypoxic conditions. The strict dependence of hydrogen oxidation of Hyd1 and Hyd2 on oxygen suggests that the enzymes are oxygen tolerant and linked to the respiratory chain. This unique combination of hydrogenases allows M. smegmatis to oxidize hydrogen at high (Hyd1) and potentially tropospheric (Hyd2) concentrations, as well as recycle reduced equivalents by evolving hydrogen (Hyd3). The distribution of these hydrogenases throughout numerous soil and marine species of actinomycetes suggests that oxic hydrogen metabolism provides metabolic flexibility in environments with changing nutrient fluxes.

Brain energy metabolism: focus on astrocyte-neuron metabolic cooperation.

PubMed

Bélanger, Mireille; Allaman, Igor; Magistretti, Pierre J

2011-12-07

The energy requirements of the brain are very high, and tight regulatory mechanisms operate to ensure adequate spatial and temporal delivery of energy substrates in register with neuronal activity. Astrocytes-a type of glial cell-have emerged as active players in brain energy delivery, production, utilization, and storage. Our understanding of neuroenergetics is rapidly evolving from a "neurocentric" view to a more integrated picture involving an intense cooperativity between astrocytes and neurons. This review focuses on the cellular aspects of brain energy metabolism, with a particular emphasis on the metabolic interactions between neurons and astrocytes. Copyright © 2011 Elsevier Inc. All rights reserved.

Regulation of Mitochondrial Function and Cellular Energy Metabolism by Protein Kinase C-λ/ι: A Novel Mode of Balancing Pluripotency

PubMed Central

Mahato, Biraj; Home, Pratik; Rajendran, Ganeshkumar; Paul, Arindam; Saha, Biswarup; Ganguly, Avishek; Ray, Soma; Roy, Nairita; Swerdlow, Russell H.; Paul, Soumen

2014-01-01

Pluripotent stem cells (PSCs) contain functionally immature mitochondria and rely upon high rates of glycolysis for their energy requirements. Thus, altered mitochondrial function and promotion of aerobic glycolysis is key to maintain and induce pluripotency. However, signaling mechanisms that regulate mitochondrial function and reprogram metabolic preferences in self-renewing vs. differentiated PSC populations are poorly understood. Here, using murine embryonic stem cells (ESCs) as a model system, we demonstrate that atypical protein kinase C isoform, PKC lambda/iota (PKCλ/ι), is a key regulator of mitochondrial function in ESCs. Depletion of PKCλ/ι in ESCs maintains their pluripotent state as evident from germline offsprings. Interestingly, loss of PKCλ/ι in ESCs leads to impairment in mitochondrial maturation, organization and a metabolic shift toward glycolysis under differentiating condition. Our mechanistic analyses indicate that a PKCλ/ι-HIF1α-PGC1α axis regulates mitochondrial respiration and balances pluripotency in ESCs. We propose that PKCλ/ι could be a crucial regulator of mitochondrial function and energy metabolism in stem cells and other cellular contexts. PMID:25142417

Regulation of mitochondrial function and cellular energy metabolism by protein kinase C-λ/ι: a novel mode of balancing pluripotency.

PubMed

Mahato, Biraj; Home, Pratik; Rajendran, Ganeshkumar; Paul, Arindam; Saha, Biswarup; Ganguly, Avishek; Ray, Soma; Roy, Nairita; Swerdlow, Russell H; Paul, Soumen

2014-11-01

Pluripotent stem cells (PSCs) contain functionally immature mitochondria and rely upon high rates of glycolysis for their energy requirements. Thus, altered mitochondrial function and promotion of aerobic glycolysis are key to maintain and induce pluripotency. However, signaling mechanisms that regulate mitochondrial function and reprogram metabolic preferences in self-renewing versus differentiated PSC populations are poorly understood. Here, using murine embryonic stem cells (ESCs) as a model system, we demonstrate that atypical protein kinase C isoform, PKC lambda/iota (PKCλ/ι), is a key regulator of mitochondrial function in ESCs. Depletion of PKCλ/ι in ESCs maintains their pluripotent state as evident from germline offsprings. Interestingly, loss of PKCλ/ι in ESCs leads to impairment in mitochondrial maturation, organization, and a metabolic shift toward glycolysis under differentiating condition. Our mechanistic analyses indicate that a PKCλ/ι-hypoxia-inducible factor 1α-PGC1α axis regulates mitochondrial respiration and balances pluripotency in ESCs. We propose that PKCλ/ι could be a crucial regulator of mitochondrial function and energy metabolism in stem cells and other cellular contexts. © 2014 AlphaMed Press.

Concurrent aerobic plus resistance exercise versus aerobic exercise alone to improve health outcomes in paediatric obesity: a systematic review and meta-analysis.

PubMed

García-Hermoso, Antonio; Ramírez-Vélez, Robinson; Ramírez-Campillo, Rodrigo; Peterson, Mark D; Martínez-Vizcaíno, Vicente

2018-02-01

To determine if the combination of aerobic and resistance exercise is superior to aerobic exercise alone for the health of obese children and adolescents. Systematic review with meta-analysis. Computerised search of 3 databases (MEDLINE, EMBASE, and Cochrane Controlled Trials Registry). Studies that compared the effect of supervised concurrent exercise versus aerobic exercise interventions, with anthropometric and metabolic outcomes in paediatric obesity (6-18 years old). The mean differences (MD) of the parameters from preintervention to postintervention between groups were pooled using a random-effects model. 12 trials with 555 youths were included in the meta-analysis. Compared with aerobic exercise alone, concurrent exercise resulted in greater reductions in body mass (MD=-2.28 kg), fat mass (MD=-3.49%; and MD=-4.34 kg) and low-density lipoprotein cholesterol (MD=-10.20 mg/dL); as well as greater increases in lean body mass (MD=2.20 kg) and adiponectin level (MD=2.59 μg/mL). Differences were larger for longer term programmes (>24 weeks). Concurrent aerobic plus resistance exercise improves body composition, metabolic profiles, and inflammatory state in the obese paediatric population. CRD42016039807. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

[Effect of aerobic exercise and resistance exercise in improving non-alcoholic fatty liver disease: a randomized controlled trial].

PubMed

Jia, G Y; Han, T; Gao, L; Wang, L; Wang, S C; Yang, L; Zhang, J; Guan, Y Y; Yan, N N; Yu, H Y; Xiao, H J; Di, F S

2018-01-20

Objective: To investigate the effect of dietary control combined with different exercise modes on plasma vaspin, irisin, and metabolic parameters in patients with non-alcoholic fatty liver disease (NAFLD) through a randomized open parallel-controlled study. Methods: The patients aged 30-65 years who visited Tianjin Third Central Hospital from January 2013 to December 2014 and were diagnosed with NAFLD by liver ultrasound and fat content determination were screening, and 474 patients were enrolled in this randomized controlled trial and divided into aerobic exercise group, resistance exercise group, and control group. All patients received dietary intervention. The three groups were compared in terms of biochemical parameters, fat content, NFS score, energy metabolic parameters, body composition index, and levels of vaspin and irisin at baseline and after 6 months of intervention. SPSS 19.0 was used for statistical analysis. The t -test, the Mann-Whitney U test, the chi-square test, and an analysis of variance were used for comparison between groups. The multiple imputation method was used for missing data, and the results were included in the intention-to-treat analysis. Results: There were no significant differences in age, sex, anthropometrical parameters, and biochemical parameters between the three groups at baseline. Compared with dietary control alone, aerobic exercise and resistance exercise helped to achieve significant reductions in waist circumference, diastolic pressure, percentage of body fat, volatile fatty acid, fasting blood glucose, homeostasis model assessment of insulin resistance, triglyceride, low-density lipoprotein cholesterol, free fatty acid, uric acid, alanine aminotransferase, and liver fat content after 6 months of intervention ( P < 0.05). The aerobic exercise group had a significant increase in non-protein respiratory quotient and significant reductions in body mass index and aspartate aminotransferase after intervention, as well as a

Metabolic plasticity and the energy economizing effect of ibogaine, the principal alkaloid of Tabernanthe iboga.

PubMed

Paškulin, Roman; Jamnik, Polona; Danevčič, Tjaša; Koželj, Gordana; Krašovec, Rok; Krstić-Milošević, Dijana; Blagojević, Duško; Strukelj, Borut

2012-08-30

The root bark of iboga plant-Tabernanthe iboga has been used traditionally in Central Africa as a psychoactive substance in religious rituals, while in smaller doses it is appreciated due to its stimulant properties. The iboga root bark, iboga extract or pure ibogaine are being recognized in the West as an anti-addiction remedy and their use is increasing. Our previous studies have demonstrated a transient ATP pool reduction under ibogaine accompanied by the induction of energy metabolism related enzymes. The present study aimed to find the cause of this energy deprivation and to foresee its immediate and long-term impact on metabolism. The overall project is designed to disclose the common mechanism of action at these seemingly diverse indications for iboga use, to predict eventual adverse effects and to build the grounds for its safe and beneficial utilization. The rate of carbon dioxide (CO(2)) as a marker of energy metabolism in stationary yeast model under aerobic conditions in the presence of ibogaine at concentration of 1, 4 and 20mg/l was measured for 5h by gas chromatography. The overall oxidative load was determined fluorimetrically by 2',7'-dichlorofluorescein diacetate (H(2)DCFDA) and in vitro antioxidant properties of ibogaine were defined by 1,1-diphenyl-2-picrylhydrazyl (DPPH) test. The CO(2) production under ibogaine was temporarily increased in a dose dependent manner. The increased energy consumption as an early effect of ibogaine was proven by the fact that in spite of energy mobilization, the ATP pool has been simultaneously decreased. Although increased cellular respiration co-produces reactive oxygen species (ROS), the overall oxidative load was significantly lowered by ibogaine. Since ibogaine does not show any significant in vitro antioxidant properties, the results indicate its stimulating influence on physiological oxidative stress defence system. Ibogaine triggers remodeling of the housekeeping metabolism. Under the initial energy cost it

Effects of Aerobic Exercise Based upon Heart Rate at Aerobic Threshold in Obese Elderly Subjects with Type 2 Diabetes

PubMed Central

Donini, Lorenzo Maria

2015-01-01

In obese diabetic subjects, a correct life style, including diet and physical activity, is part of a correct intervention protocol. Thus, the aim of this study was to evaluate the effects of aerobic training intervention, based on heart rate at aerobic gas exchange threshold (AerTge), on clinical and physiological parameters in obese elderly subjects with type 2 diabetes (OT2DM). Thirty OT2DM subjects were randomly assigned to an intervention (IG) or control group (CG). The IG performed a supervised aerobic exercise training based on heart rate at AerTge whereas CG maintained their usual lifestyle. Anthropometric measures, blood analysis, peak oxygen consumption (V˙O2peak), metabolic equivalent (METpeak), work rate (WRpeak), and WRAerTge were assessed at baseline and after intervention. After training, patients enrolled in the IG had significantly higher (P < 0.001) V˙O2peak, METpeak, WRpeak, and WRAerTge and significantly lower (P < 0.005) weight, BMI, %FM, and waist circumference than before intervention. Both IG and CG subjects had lower glycated haemoglobin levels after intervention period. No significant differences were found for all the other parameters between pre- and posttraining and between groups. Aerobic exercise prescription based upon HR at AerTge could be a valuable physical intervention tool to improve the fitness level and metabolic equilibrium in OT2DM patients. PMID:26089890

Yeast vitality during cider fermentation: assessment by energy metabolism.

PubMed

Dinsdale, M G; Lloyd, D; McIntyre, P; Jarvis, B

1999-03-15

In an apple juice-based medium, an ethanol-tolerant Australian wine-yeast used for cider manufacture produced more than 10% ethanol over a 5 week period. Growth of the inoculum (10(6) organisms ml(-1)) occurred to a population of 3.1 x 10(7) ml(-1) during the first few days; at the end of the fermentation only 5 x 10(5) yeasts ml(-1) could be recovered as colony-forming units on plates. Respiratory and fermentative activities were measured by mass spectrometric measurements (O2 consumption and CO2 and ethanol production) of washed yeast suspensions taken from the cider fermentation at intervals. Both endogenous and glucose-supported energy-yielding metabolism declined, especially during the first 20 days. Levels of adenine nucleotides also showed decreases after day 1, as did adenylate energy charge, although in a prolonged (16.5 week) fermentation the lowest value calculated was 0.55. AMP was released into the medium. 31P-NMR spectra showed that by comparison with aerobically grown yeast, that from the later stages of the cider fermentation showed little polyphosphate. However, as previously concluded from studies of 'acidification power' and fluorescent oxonol dye exclusion (Dinsdale et al., 1995), repitching of yeast indicated little loss of viability despite considerable loss of vitality.

A simple and affordable calorespirometer for assessing the metabolic rates of fishes.

PubMed

Regan, M D; Gosline, J M; Richards, J G

2013-12-15

Calorimetry is the measurement of the heat liberated during energy transformations in chemical reactions. When applied to living organisms, it measures the heat released due to the energy transformations associated with metabolism under both aerobic and anaerobic conditions. This is in contrast to the often-used respirometric techniques for assessing energy turnover, which can only be used under fully aerobic conditions. Accordingly, calorimetry is considered the 'gold standard' for quantifying metabolic rate, yet despite this, it remains a seldom-used technique among comparative physiologists. The reasons for this are related to the expense and perceived difficulty of the technique. We have designed and constructed an inexpensive flow-through calorespirometer capable of detecting rates of metabolic heat loss and oxygen consumption (O2) in fish under a variety of environmental conditions over long-term experiments. The metabolic heat of the fish is detected as a voltage by a collection of Peltier units wired in series, while oxygen optodes placed on the inflowing and outflowing water lines are used for the calculation of O2. The apparatus is constructed in a differential fashion to account for ambient temperature fluctuations. This paper describes the design and construction of the calorespirometer for ~$1300 CDN. Using the goldfish (Carassius auratus auratus), we show that the calorespirometer is sensitive to changes in metabolic rate brought about by pharmacological manipulation and severe hypoxia exposures.

Energy metabolism in the liver.

PubMed

Rui, Liangyou

2014-01-01

The liver is an essential metabolic organ, and its metabolic function is controlled by insulin and other metabolic hormones. Glucose is converted into pyruvate through glycolysis in the cytoplasm, and pyruvate is subsequently oxidized in the mitochondria to generate ATP through the TCA cycle and oxidative phosphorylation. In the fed state, glycolytic products are used to synthesize fatty acids through de novo lipogenesis. Long-chain fatty acids are incorporated into triacylglycerol, phospholipids, and/or cholesterol esters in hepatocytes. These complex lipids are stored in lipid droplets and membrane structures, or secreted into the circulation as very low-density lipoprotein particles. In the fasted state, the liver secretes glucose through both glycogenolysis and gluconeogenesis. During pronged fasting, hepatic gluconeogenesis is the primary source for endogenous glucose production. Fasting also promotes lipolysis in adipose tissue, resulting in release of nonesterified fatty acids which are converted into ketone bodies in hepatic mitochondria though β-oxidation and ketogenesis. Ketone bodies provide a metabolic fuel for extrahepatic tissues. Liver energy metabolism is tightly regulated by neuronal and hormonal signals. The sympathetic system stimulates, whereas the parasympathetic system suppresses, hepatic gluconeogenesis. Insulin stimulates glycolysis and lipogenesis but suppresses gluconeogenesis, and glucagon counteracts insulin action. Numerous transcription factors and coactivators, including CREB, FOXO1, ChREBP, SREBP, PGC-1α, and CRTC2, control the expression of the enzymes which catalyze key steps of metabolic pathways, thus controlling liver energy metabolism. Aberrant energy metabolism in the liver promotes insulin resistance, diabetes, and nonalcoholic fatty liver diseases. © 2014 American Physiological Society.

Aerobic interval training reduces vascular resistances during submaximal exercise in obese metabolic syndrome individuals.

PubMed

Mora-Rodriguez, Ricardo; Fernandez-Elias, V E; Morales-Palomo, F; Pallares, J G; Ramirez-Jimenez, M; Ortega, J F

2017-10-01

The aim of this study was to determine the effects of high-intensity aerobic interval training (AIT) on exercise hemodynamics in metabolic syndrome (MetS) volunteers. Thirty-eight, MetS participants were randomly assigned to a training (TRAIN) or to a non-training control (CONT) group. TRAIN consisted of stationary interval cycling alternating bouts at 70-90% of maximal heart rate during 45 min day -1 for 6 months. CONT maintained baseline physical activity and no changes in cardiovascular function or MetS factors were detected. In contrast, TRAIN increased cardiorespiratory fitness (14% in VO 2PEAK ; 95% CI 9-18%) and improved metabolic syndrome (-42% in Z score; 95% CI 83-1%). After TRAIN, the workload that elicited a VO 2 of 1500 ml min -1 increased 15% (95% CI 5-25%; P < 0.001). After TRAIN when subjects pedaled at an identical submaximal rate of oxygen consumption, cardiac output increased by 8% (95% CI 4-11%; P < 0.01) and stroke volume by 10% (95% CI, 6-14%; P < 0.005) being above the CONT group values at that time point. TRAIN reduced submaximal exercise heart rate (109 ± 15-106 ± 13 beats min -1 ; P < 0.05), diastolic blood pressure (83 ± 8-75 ± 8 mmHg; P < 0.001) and systemic vascular resistances (P < 0.01) below CONT values. Double product was reduced only after TRAIN (18.2 ± 3.2-17.4 ± 2.4 bt min -1  mmHg 10 -3 ; P < 0.05). The data suggest that intense aerobic interval training improves hemodynamics during submaximal exercise in MetS patients. Specifically, it reduces diastolic blood pressure, systemic vascular resistances, and the double product. The reduction in double product, suggests decreased myocardial oxygen demands which could prevent the occurrence of adverse cardiovascular events during exercise in this population. CLINICALTRIALS. NCT03019796.

Metatranscriptomic analysis of a high-sulfide aquatic spring reveals insights into sulfur cycling and unexpected aerobic metabolism

PubMed Central

Elshahed, Mostafa S.; Najar, Fares Z.; Krumholz, Lee R.

2015-01-01

Zodletone spring is a sulfide-rich spring in southwestern Oklahoma characterized by shallow, microoxic, light-exposed spring water overlaying anoxic sediments. Previously, culture-independent 16S rRNA gene based diversity surveys have revealed that Zodletone spring source sediments harbor a highly diverse microbial community, with multiple lineages putatively involved in various sulfur-cycling processes. Here, we conducted a metatranscriptomic survey of microbial populations in Zodletone spring source sediments to characterize the relative prevalence and importance of putative phototrophic, chemolithotrophic, and heterotrophic microorganisms in the sulfur cycle, the identity of lineages actively involved in various sulfur cycling processes, and the interaction between sulfur cycling and other geochemical processes at the spring source. Sediment samples at the spring’s source were taken at three different times within a 24-h period for geochemical analyses and RNA sequencing. In depth mining of datasets for sulfur cycling transcripts revealed major sulfur cycling pathways and taxa involved, including an unexpected potential role of Actinobacteria in sulfide oxidation and thiosulfate transformation. Surprisingly, transcripts coding for the cyanobacterial Photosystem II D1 protein, methane monooxygenase, and terminal cytochrome oxidases were encountered, indicating that genes for oxygen production and aerobic modes of metabolism are actively being transcribed, despite below-detectable levels (<1 µM) of oxygen in source sediment. Results highlight transcripts involved in sulfur, methane, and oxygen cycles, propose that oxygenic photosynthesis could support aerobic methane and sulfide oxidation in anoxic sediments exposed to sunlight, and provide a viewpoint of microbial metabolic lifestyles under conditions similar to those seen during late Archaean and Proterozoic eons. PMID:26417542

Metatranscriptomic analysis of a high-sulfide aquatic spring reveals insights into sulfur cycling and unexpected aerobic metabolism.

PubMed

Spain, Anne M; Elshahed, Mostafa S; Najar, Fares Z; Krumholz, Lee R

2015-01-01

Zodletone spring is a sulfide-rich spring in southwestern Oklahoma characterized by shallow, microoxic, light-exposed spring water overlaying anoxic sediments. Previously, culture-independent 16S rRNA gene based diversity surveys have revealed that Zodletone spring source sediments harbor a highly diverse microbial community, with multiple lineages putatively involved in various sulfur-cycling processes. Here, we conducted a metatranscriptomic survey of microbial populations in Zodletone spring source sediments to characterize the relative prevalence and importance of putative phototrophic, chemolithotrophic, and heterotrophic microorganisms in the sulfur cycle, the identity of lineages actively involved in various sulfur cycling processes, and the interaction between sulfur cycling and other geochemical processes at the spring source. Sediment samples at the spring's source were taken at three different times within a 24-h period for geochemical analyses and RNA sequencing. In depth mining of datasets for sulfur cycling transcripts revealed major sulfur cycling pathways and taxa involved, including an unexpected potential role of Actinobacteria in sulfide oxidation and thiosulfate transformation. Surprisingly, transcripts coding for the cyanobacterial Photosystem II D1 protein, methane monooxygenase, and terminal cytochrome oxidases were encountered, indicating that genes for oxygen production and aerobic modes of metabolism are actively being transcribed, despite below-detectable levels (<1 µM) of oxygen in source sediment. Results highlight transcripts involved in sulfur, methane, and oxygen cycles, propose that oxygenic photosynthesis could support aerobic methane and sulfide oxidation in anoxic sediments exposed to sunlight, and provide a viewpoint of microbial metabolic lifestyles under conditions similar to those seen during late Archaean and Proterozoic eons.

Arginine and aerobic training prevent endothelial and metabolic alterations in rats at high risk for the development of the metabolic syndrome.

PubMed

Medeiros, Renata F; Gaique, Thaiane G; Bento-Bernardes, Thais; Kindlovits, Raquel; Gomes, Tamiris M B; Motta, Nadia Alice V; Brito, Fernanda Carla; Fernandes-Santos, Caroline; Oliveira, Karen J; Nóbrega, Antonio Claudio L

2017-07-01

Endothelial function is a key mechanism in the development of CVD. Arginine and exercise are important non-pharmacological strategies for mitigating the impact of metabolic changes in the metabolic syndrome, but the effect of their combined administration is unknown. Thus, the aim of this study was to investigate the isolated and combined effects of aerobic training and arginine supplementation on metabolic variables and vascular reactivity in rats at high risk for developing the metabolic syndrome. Wistar rats were divided into two groups: control and fructose (F - water with 10 % fructose). After 2 weeks, the F group was divided into four groups: F, fructose+arginine (FA, 880 mg/kg per d of l-arginine), fructose+training (FT) and fructose+arginine+training (FTA); treatments lasted for 8 weeks, and no difference was observed in body mass gain. Arginine did not improve the body protein content, and both the FA and FT groups show a reversal of the increase in adipose tissue. Insulin increase was prevented by training and arginine, without additive effect, and the increase in serum TAG was prevented only by training. The F group showed impaired endothelium-dependent vasodilation and hyperreactivity to phenylephrine, but arginine and training were capable of preventing these effects, even separately. Higher nitric oxide level was observed in the FA and FT groups, and no potentiating effect was detected. Thus, only training was able to prevent the increase in TAG and improve the protein mass, and training and arginine exert similar effects on fat content, insulin and endothelial function, but these effects are not additive.

TRPV1 activation improves exercise endurance and energy metabolism through PGC-1α upregulation in mice

PubMed Central

Luo, Zhidan; Ma, Liqun; Zhao, Zhigang; He, Hongbo; Yang, Dachun; Feng, Xiaoli; Ma, Shuangtao; Chen, Xiaoping; Zhu, Tianqi; Cao, Tingbing; Liu, Daoyan; Nilius, Bernd; Huang, Yu; Yan, Zhencheng; Zhu, Zhiming

2012-01-01

Impaired aerobic exercise capacity and skeletal muscle dysfunction are associated with cardiometabolic diseases. Acute administration of capsaicin enhances exercise endurance in rodents, but the long-term effect of dietary capsaicin is unknown. The capsaicin receptor, the transient receptor potential vanilloid 1 (TRPV1) cation channel has been detected in skeletal muscle, the role of which remains unclear. Here we report the function of TRPV1 in cultured C2C12 myocytes and the effect of TRPV1 activation by dietary capsaicin on energy metabolism and exercise endurance of skeletal muscles in mice. In vitro, capsaicin increased cytosolic free calcium and peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) expression in C2C12 myotubes through activating TRPV1. In vivo, PGC-1α in skeletal muscle was upregulated by capsaicin-induced TRPV1 activation or genetic overexpression of TRPV1 in mice. TRPV1 activation increased the expression of genes involved in fatty acid oxidation and mitochondrial respiration, promoted mitochondrial biogenesis, increased oxidative fibers, enhanced exercise endurance and prevented high-fat diet-induced metabolic disorders. Importantly, these effects of capsaicin were absent in TRPV1-deficient mice. We conclude that TRPV1 activation by dietary capsaicin improves energy metabolism and exercise endurance by upregulating PGC-1α in skeletal muscles. The present results indicate a novel therapeutic strategy for managing metabolic diseases and improving exercise endurance. PMID:22184011

Aerobic glycolysis tunes YAP/TAZ transcriptional activity

PubMed Central

Enzo, Elena; Santinon, Giulia; Pocaterra, Arianna; Aragona, Mariaceleste; Bresolin, Silvia; Forcato, Mattia; Grifoni, Daniela; Pession, Annalisa; Zanconato, Francesca; Guzzo, Giulia; Bicciato, Silvio; Dupont, Sirio

2015-01-01

Increased glucose metabolism and reprogramming toward aerobic glycolysis are a hallmark of cancer cells, meeting their metabolic needs for sustained cell proliferation. Metabolic reprogramming is usually considered as a downstream consequence of tumor development and oncogene activation; growing evidence indicates, however, that metabolism on its turn can support oncogenic signaling to foster tumor malignancy. Here, we explored how glucose metabolism regulates gene transcription and found an unexpected link with YAP/TAZ, key transcription factors regulating organ growth, tumor cell proliferation and aggressiveness. When cells actively incorporate glucose and route it through glycolysis, YAP/TAZ are fully active; when glucose metabolism is blocked, or glycolysis is reduced, YAP/TAZ transcriptional activity is decreased. Accordingly, glycolysis is required to sustain YAP/TAZ pro-tumorigenic functions, and YAP/TAZ are required for the full deployment of glucose growth-promoting activity. Mechanistically we found that phosphofructokinase (PFK1), the enzyme regulating the first committed step of glycolysis, binds the YAP/TAZ transcriptional cofactors TEADs and promotes their functional and biochemical cooperation with YAP/TAZ. Strikingly, this regulation is conserved in Drosophila, where phosphofructokinase is required for tissue overgrowth promoted by Yki, the fly homologue of YAP. Moreover, gene expression regulated by glucose metabolism in breast cancer cells is strongly associated in a large dataset of primary human mammary tumors with YAP/TAZ activation and with the progression toward more advanced and malignant stages. These findings suggest that aerobic glycolysis endows cancer cells with particular metabolic properties and at the same time sustains transcription factors with potent pro-tumorigenic activities such as YAP/TAZ. PMID:25796446

Aerobic, resistance or combined training: A systematic review and meta-analysis of exercise to reduce cardiovascular risk in adults with metabolic syndrome.

PubMed

Wewege, Michael A; Thom, Jeanette M; Rye, Kerry-Anne; Parmenter, Belinda J

2018-05-03

Exercise is beneficial to individuals with metabolic syndrome (MetS). An understudied group, who represent the majority of the MetS population, are individuals who have not developed diabetes. This review examined aerobic, resistance and combined (aerobic + resistance) exercise for cardiovascular risk factors in MetS without diabetes. Eight electronic databases were searched up to September 2017 for randomised controlled trials >4 weeks in duration that compared an exercise intervention to the non-exercise control in MetS without diabetes. MetS criteria, cardiorespiratory fitness and cardiovascular risk factors were meta-analysed in a random effects model. Eleven studies with 16 interventions were included (12 aerobic, 4 resistance). Aerobic exercise significantly improved waist circumference -3.4 cm (p < 0.01), fasting glucose -0.15 mmol/L (p = 0.03), high-density cholesterol 0.05 mmol/L (p = 0.02), triglycerides -0.29 mmol/L (p < 0.01), diastolic blood pressure -1.6 mmHg (p = 0.01), and cardiorespiratory fitness 4.2 ml/kg/min (p < 0.01), among other outcomes. No significant effects were determined following resistance exercise possibly due to limited data. Sub-analyses suggested that aerobic exercise progressed to vigorous intensity, and conducted 3 days/week for ≥12 weeks offered larger and more widespread improvements. Aerobic exercise following current guidelines offers widespread benefits to individuals with MetS without diabetes. More studies on resistance/combined exercise programs in MetS are required to improve the quality of evidence. Copyright © 2018 Elsevier B.V. All rights reserved.

Aerobic Exercise Attenuates the Loss of Skeletal Muscle during Energy Restriction in Adults with Visceral Adiposity

PubMed Central

Yoshimura, Eiichi; Kumahara, Hideaki; Tobina, Takuro; Matsuda, Takuro; Watabe, Kiwa; Matono, Sakiko; Ayabe, Makoto; Kiyonaga, Akira; Anzai, Keizo; Higaki, Yasuki; Tanaka, Hiroaki

2014-01-01

Objective To evaluate the effects of energy restriction with or without aerobic exercise on thigh muscle mass and quality in adults with visceral adiposity. Methods 75 males and females were randomly assigned to the groups ‘diet only’ (DO; n = 42) or ‘diet plus aerobic exercise’ (D/Ex; n = 33) for 12 weeks. The target energy intake in both groups was 25 kcal/kg of ideal body weight. Subjects in the D/Ex group were instructed to exercise for ≥300 min/week at lactate threshold. Computed tomography was used to measure thigh muscle cross-sectional area (CSA), normal-density muscle area (NDMA), and visceral fat area. Results Total body weight (DO: −6.6 ± 3.6%; D/Ex: −7.3 ± 4.6%) and visceral fat (DO: −16.0 ± 13.8%; D/Ex: −23.1 ± 14.7%) decreased significantly in both groups; however, the changes were not significantly different between the two groups. The decrease in muscle CSA was significantly greater in the DO group (-5.1 ± 4.5%) compared with the D/Ex group (-2.5 ± 5.0%). NDMA decreased significantly in the DO (-4.9 ± 4.9%) but not in the D/Ex group (-1.4 ± 5.0%). Conclusion Aerobic exercise attenuated the loss of skeletal muscle during energy restriction in adults with visceral adiposity. PMID:24457527

Phylogenetic Analysis Supports the Aerobic-Capacity Model for the Evolution of Endothermy.

PubMed

Nespolo, Roberto F; Solano-Iguaran, Jaiber J; Bozinovic, Francisco

2017-01-01

The evolution of endothermy is a controversial topic in evolutionary biology, although several hypotheses have been proposed to explain it. To a great extent, the debate has centered on the aerobic-capacity model (AC model), an adaptive hypothesis involving maximum and resting rates of metabolism (MMR and RMR, respectively; hereafter "metabolic traits"). The AC model posits that MMR, a proxy of aerobic capacity and sustained activity, is the target of directional selection and that RMR is also influenced as a correlated response. Associated with this reasoning are the assumptions that (1) factorial aerobic scope (FAS; MMR/RMR) and net aerobic scope (NAS; MMR - RMR), two commonly used indexes of aerobic capacity, show different evolutionary optima and (2) the functional link between MMR and RMR is a basic design feature of vertebrates. To test these assumptions, we performed a comparative phylogenetic analysis in 176 vertebrate species, ranging from fish and amphibians to birds and mammals. Using disparity-through-time analysis, we also explored trait diversification and fitted different evolutionary models to study the evolution of metabolic traits. As predicted, we found (1) a positive phylogenetic correlation between RMR and MMR, (2) diversification of metabolic traits exceeding that of random-walk expectations, (3) that a model assuming selection fits the data better than alternative models, and (4) that a single evolutionary optimum best fits FAS data, whereas a model involving two optima (one for ectotherms and another for endotherms) is the best explanatory model for NAS. These results support the AC model and give novel information concerning the mode and tempo of physiological evolution of vertebrates.

Exercise effect with the wheelchair aerobic fitness trainer on conditioning and metabolic function in disabled persons: a pilot study.

PubMed

Midha, M; Schmitt, J K; Sclater, M

1999-03-01

To determine the effect of exercise with the wheelchair aerobic fitness trainer (WAFT) on anthropometric indices, conditioning, and endocrine and metabolic parameters in persons with lower extremity disability. Exercise sessions with the WAFT lasted 20 to 30 minutes for two to three sessions. Tertiary-care Veterans Administration medical center. Twelve subjects (3 with quadriplegia, 7 with paraplegia, 1 with cerebrovascular accident, 1 with bilateral above-knee amputation). Anthropometric indices (heart rate, blood pressure, weight, oxygen utilization, body mass index, upper arm and abdominal circumference, arm power) and endocrine and metabolic parameters (fasting serum glucose, lipids, and thyroid function) were determined before and after 10 weeks of exercise with the WAFT. All patients noted improved feelings of well-being after training. Mean resting heart rate, upper arm fat area, and fasting serum cholesterol level decreased significantly. Peak oxygen consumption, midarm circumference, and free thyroxine index increased significantly with training. WAFT improves quality of life, conditioning, and endocrine-metabolic parameters in disabled persons.

How doth the little busy bee: unexpected metabolism.

PubMed

Barros, L Felipe; Sierralta, Jimena; Weber, Bruno

2015-01-01

Brain energy metabolism powers information processing and behavior, much as electricity powers a computer. However, a recent study in insects suggests that this relationship is more interesting, causally linking aggressive behavior to energetics. These findings may also shed new light on aerobic glycolysis, a long-standing riddle of human brain physiology. Copyright © 2014 Elsevier Ltd. All rights reserved.

[Aerobic methylobacteria as promising objects of modern biotechnology].

PubMed

Doronina, N V; Toronskava, L; Fedorov, D N; Trotsenko, Yu A

2015-01-01

The experimental data of the past decade concerning the metabolic peculiarities of aerobic meth ylobacteria and the prospects for their use in different fields of modern biotechnology, including genetic engineering techniques, have been summarized.

Aerobic Glycolysis Is Essential for Normal Rod Function and Controls Secondary Cone Death in Retinitis Pigmentosa.

PubMed

Petit, Lolita; Ma, Shan; Cipi, Joris; Cheng, Shun-Yun; Zieger, Marina; Hay, Nissim; Punzo, Claudio

2018-05-29

Aerobic glycolysis accounts for ∼80%-90% of glucose used by adult photoreceptors (PRs); yet, the importance of aerobic glycolysis for PR function or survival remains unclear. Here, we further established the role of aerobic glycolysis in murine rod and cone PRs. We show that loss of hexokinase-2 (HK2), a key aerobic glycolysis enzyme, does not affect PR survival or structure but is required for normal rod function. Rods with HK2 loss increase their mitochondrial number, suggesting an adaptation to the inhibition of aerobic glycolysis. In contrast, cones adapt without increased mitochondrial number but require HK2 to adapt to metabolic stress conditions such as those encountered in retinitis pigmentosa, where the loss of rods causes a nutrient shortage in cones. The data support a model where aerobic glycolysis in PRs is not a necessity but rather a metabolic choice that maximizes PR function and adaptability to nutrient stress conditions. Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.

Understanding the Warburg effect: the metabolic requirements of cell proliferation.

PubMed

Vander Heiden, Matthew G; Cantley, Lewis C; Thompson, Craig B

2009-05-22

In contrast to normal differentiated cells, which rely primarily on mitochondrial oxidative phosphorylation to generate the energy needed for cellular processes, most cancer cells instead rely on aerobic glycolysis, a phenomenon termed "the Warburg effect." Aerobic glycolysis is an inefficient way to generate adenosine 5'-triphosphate (ATP), however, and the advantage it confers to cancer cells has been unclear. Here we propose that the metabolism of cancer cells, and indeed all proliferating cells, is adapted to facilitate the uptake and incorporation of nutrients into the biomass (e.g., nucleotides, amino acids, and lipids) needed to produce a new cell. Supporting this idea are recent studies showing that (i) several signaling pathways implicated in cell proliferation also regulate metabolic pathways that incorporate nutrients into biomass; and that (ii) certain cancer-associated mutations enable cancer cells to acquire and metabolize nutrients in a manner conducive to proliferation rather than efficient ATP production. A better understanding of the mechanistic links between cellular metabolism and growth control may ultimately lead to better treatments for human cancer.

PKM2 methylation by CARM1 activates aerobic glycolysis to promote tumorigenesis.

PubMed

Liu, Fabao; Ma, Fengfei; Wang, Yuyuan; Hao, Ling; Zeng, Hao; Jia, Chenxi; Wang, Yidan; Liu, Peng; Ong, Irene M; Li, Baobin; Chen, Guojun; Jiang, Jiaoyang; Gong, Shaoqin; Li, Lingjun; Xu, Wei

2017-11-01

Metabolic reprogramming is a hallmark of cancer. Herein we discover that the key glycolytic enzyme pyruvate kinase M2 isoform (PKM2), but not the related isoform PKM1, is methylated by co-activator-associated arginine methyltransferase 1 (CARM1). PKM2 methylation reversibly shifts the balance of metabolism from oxidative phosphorylation to aerobic glycolysis in breast cancer cells. Oxidative phosphorylation depends on mitochondrial calcium concentration, which becomes critical for cancer cell survival when PKM2 methylation is blocked. By interacting with and suppressing the expression of inositol-1,4,5-trisphosphate receptors (InsP 3 Rs), methylated PKM2 inhibits the influx of calcium from the endoplasmic reticulum to mitochondria. Inhibiting PKM2 methylation with a competitive peptide delivered by nanoparticles perturbs the metabolic energy balance in cancer cells, leading to a decrease in cell proliferation, migration and metastasis. Collectively, the CARM1-PKM2 axis serves as a metabolic reprogramming mechanism in tumorigenesis, and inhibiting PKM2 methylation generates metabolic vulnerability to InsP 3 R-dependent mitochondrial functions.

PKM2 methylation by CARM1 activates aerobic glycolysis to promote tumorigenesis

PubMed Central

Liu, Fabao; Ma, Fengfei; Wang, Yuyuan; Hao, Ling; Zeng, Hao; Jia, Chenxi; Wang, Yidan; Liu, Peng; Ong, Irene M; Li, Baobin; Chen, Guojun; Jiang, Jiaoyang; Gong, Shaoqin; Li, Lingjun; Xu, Wei

2017-01-01

Metabolic reprogramming is a hallmark of cancer. Herein we discovered that the key glycolytic enzyme pyruvate kinase M2 isoform (PKM2), but not the related isoform PKM1, is methylated by co-activator associated arginine methyltransferase 1 (CARM1). PKM2 methylation reversibly shifts the balance of metabolism from oxidative phosphorylation to aerobic glycolysis in breast cancer cells. Oxidative phosphorylation depends on mitochondria calcium concentration, which becomes critical for cancer cell survival when PKM2 methylation is blocked. By interacting with and suppressing the expression of inositol 1, 4, 5-trisphosphate receptors (IP3Rs), methylated PKM2 inhibits the influx of calcium from endoplasmic reticulum (ER) to mitochondria. Inhibiting PKM2 methylation with a competitive peptide delivered by nanoparticle perturbs metabolic energy balance in cancer cells, leading to decrease of cell proliferation, migration, and metastasis. Collectively, the CARM1-PKM2 axis serves as a metabolic reprogramming mechanism in tumorigenesis, and inhibiting PKM2 methylation generates metabolic vulnerability to IP3R-dependent mitochondrial functions. PMID:29058718

A practice-changing culture method relying on shaking substantially increases mitochondrial energy metabolism and functionality of human liver cell lines.

PubMed

Adam, Aziza A A; van der Mark, Vincent A; Donkers, Joanne M; Wildenberg, Manon E; Oude Elferink, Ronald P J; Chamuleau, Robert A F M; Hoekstra, Ruurdtje

2018-01-01

Practice-changing culturing techniques of hepatocytes are highly required to increase their differentiation. Previously, we found that human liver cell lines HepaRG and C3A acquire higher functionality and increased mitochondrial biogenesis when cultured in the AMC-Bioartificial liver (BAL). Dynamic medium flow (DMF) is one of the major contributors to this stimulatory effect. Recently, we found that DMF-culturing by shaking of HepaRG monolayers resulted in higher mitochondrial biogenesis. Here we further investigated the effect of DMF-culturing on energy metabolism and hepatic functionality of HepaRG and C3A monolayers. HepaRG and C3A DMF-monolayers were incubated with orbital shaking at 60 rpm during the differentiation phase, while control monolayers were maintained statically. Subsequently, energy metabolism and hepatic functionality were compared between static and DMF-cultures. DMF-culturing of HepaRG cells substantially increased hepatic differentiation; transcript levels of hepatic structural genes and hepatic transcription regulators were increased up to 15-fold (Cytochrome P450 3A4) and nuclear translocation of hepatic transcription factor CEBPα was stimulated. Accordingly, hepatic functions were positively affected, including ammonia elimination, urea production, bile acid production, and CYP3A4 activity. DMF-culturing shifted energy metabolism from aerobic glycolysis towards oxidative phosphorylation, as indicated by a decline in lactate production and glucose consumption, and an increase in oxygen consumption. Similarly, DMF-culturing increased mitochondrial energy metabolism and hepatic functionality of C3A cells. In conclusion, simple shaking of monolayer cultures substantially improves mitochondrial energy metabolism and hepatic differentiation of human liver cell lines. This practice-changing culture method may prove to prolong the in-vitro maintenance of primary hepatocytes and increase hepatic differentiation of stem cells.

Impact of mild versus moderate intensity aerobic walking exercise training on markers of bone metabolism and hand grip strength in moderate hemophilic A patients.

PubMed

Al-Sharif, Fadwa Al-Ghalib; Al-Jiffri, Osama Hussien; El-Kader, Shehab Mahmoud Abd; Ashmawy, Eman Mohamed

2014-03-01

Patients with hemophilia A have low bone density than healthy controls. It is now widely recognized that physical activity and sports are beneficial for patients with hemophilia. To compare the effects of mild and moderate intensity treadmill walking exercises on markers of bone metabolism and hand grip strength in male patients with moderate hemophilia A. Fifty male patients with moderate hemophilia, and age range from 25 to 45 years. The subjects were randomly assigned into 2 equal groups; the first group (A) received moderate intensity aerobic exercise training. The second group (B) received mild intensity aerobic exercise training. There was a 32.1% and 24.8% increase in mean values of serum calcium and hand grip strength respectively and 22.7 % reduction in mean values of parathyroid hormone in moderate exercise training group (A). While there was a 15.1 % and 15 % increase in mean values of Serum Calcium and Hand grip strength respectively and 10.3 % reduction in mean values of parathyroid hormone in mild exercise training group(B). The mean values of serum calcium and hand grip strength were significantly increased, while the mean values of parathyroid hormone were significantly decreased in both groups . There were significant differences between mean levels of the investigated parameters in group (A) and group (B) after treatment. Moderate intensity aerobic exercise training on treadmill is appropriate to improve markers of bone metabolism and hand grip strength in male patients with hemophilia A.

Energy Metabolism in the Liver

PubMed Central

Rui, Liangyou

2014-01-01

The liver is an essential metabolic organ, and its metabolic activity is tightly controlled by insulin and other metabolic hormones. Glucose is metabolized into pyruvate through glycolysis in the cytoplasm, and pyruvate is completely oxidized to generate ATP through the TCA cycle and oxidative phosphorylation in the mitochondria. In the fed state, glycolytic products are used to synthesize fatty acids through de novo lipogenesis. Long-chain fatty acids are incorporated into triacylglycerol, phospholipids, and cholesterol esters in hepatocytes, and these complex lipids are stored in lipid droplets and membrane structures, or secreted into the circulation as VLDL particles. In the fasted state, the liver secretes glucose through both breakdown of glycogen (glycogenolysis) and de novo glucose synthesis (gluconeogenesis). During pronged fasting, hepatic gluconeogenesis is the primary source of endogenous glucose production. Fasting also promotes lipolysis in adipose tissue to release nonesterified fatty acids which are converted into ketone bodies in the liver though mitochondrial β oxidation and ketogenesis. Ketone bodies provide a metabolic fuel for extrahepatic tissues. Liver metabolic processes are tightly regulated by neuronal and hormonal systems. The sympathetic system stimulates, whereas the parasympathetic system suppresses, hepatic gluconeogenesis. Insulin stimulates glycolysis and lipogenesis, but suppresses gluconeogenesis; glucagon counteracts insulin action. Numerous transcription factors and coactivators, including CREB, FOXO1, ChREBP, SREBP, PGC-1α, and CRTC2, control the expression of the enzymes which catalyze the rate-limiting steps of liver metabolic processes, thus controlling liver energy metabolism. Aberrant energy metabolism in the liver promotes insulin resistance, diabetes, and nonalcoholic fatty liver diseases (NAFLD). PMID:24692138

Energy Expenditure and Metabolic Changes of Free-Flying Migrating Northern Bald Ibis.

PubMed

Bairlein, Franz; Fritz, Johannes; Scope, Alexandra; Schwendenwein, Ilse; Stanclova, Gabriela; van Dijk, Gertjan; Meijer, Harro A J; Verhulst, Simon; Dittami, John

2015-01-01

Many migrating birds undertake extraordinary long flights. How birds are able to perform such endurance flights of over 100-hour durations is still poorly understood. We examined energy expenditure and physiological changes in Northern Bald Ibis Geronticus eremite during natural flights using birds trained to follow an ultra-light aircraft. Because these birds were tame, with foster parents, we were able to bleed them immediately prior to and after each flight. Flight duration was experimentally designed ranging between one and almost four hours continuous flights. Energy expenditure during flight was estimated using doubly-labelled-water while physiological properties were assessed through blood chemistry including plasma metabolites, enzymes, electrolytes, blood gases, and reactive oxygen compounds. Instantaneous energy expenditure decreased with flight duration, and the birds appeared to balance aerobic and anaerobic metabolism, using fat, carbohydrate and protein as fuel. This made flight both economic and tolerable. The observed effects resemble classical exercise adaptations that can limit duration of exercise while reducing energetic output. There were also in-flight benefits that enable power output variation from cruising to manoeuvring. These adaptations share characteristics with physiological processes that have facilitated other athletic feats in nature and might enable the extraordinary long flights of migratory birds as well.

Energy Expenditure and Metabolic Changes of Free-Flying Migrating Northern Bald Ibis

PubMed Central

Bairlein, Franz; Fritz, Johannes; Scope, Alexandra; Schwendenwein, Ilse; Stanclova, Gabriela; van Dijk, Gertjan; Meijer, Harro A. J.; Verhulst, Simon

2015-01-01

Many migrating birds undertake extraordinary long flights. How birds are able to perform such endurance flights of over 100-hour durations is still poorly understood. We examined energy expenditure and physiological changes in Northern Bald Ibis Geronticus eremite during natural flights using birds trained to follow an ultra-light aircraft. Because these birds were tame, with foster parents, we were able to bleed them immediately prior to and after each flight. Flight duration was experimentally designed ranging between one and almost four hours continuous flights. Energy expenditure during flight was estimated using doubly-labelled-water while physiological properties were assessed through blood chemistry including plasma metabolites, enzymes, electrolytes, blood gases, and reactive oxygen compounds. Instantaneous energy expenditure decreased with flight duration, and the birds appeared to balance aerobic and anaerobic metabolism, using fat, carbohydrate and protein as fuel. This made flight both economic and tolerable. The observed effects resemble classical exercise adaptations that can limit duration of exercise while reducing energetic output. There were also in-flight benefits that enable power output variation from cruising to manoeuvring. These adaptations share characteristics with physiological processes that have facilitated other athletic feats in nature and might enable the extraordinary long flights of migratory birds as well. PMID:26376193

Aerobic Physical Activity and the Leadership of Principals

ERIC Educational Resources Information Center

Kiser, Kari

2016-01-01

The purpose of this study was to explore if there was a connection between regular aerobic physical activity and the stress and energy levels of principals as they reported it. To begin the research, the current aerobic physical activity level of principals was discovered. Additionally, the energy and stress levels of the principals who do engage…

Catabolic efficiency of aerobic glycolysis: the Warburg effect revisited.

PubMed

Vazquez, Alexei; Liu, Jiangxia; Zhou, Yi; Oltvai, Zoltán N

2010-05-06

Cancer cells simultaneously exhibit glycolysis with lactate secretion and mitochondrial respiration even in the presence of oxygen, a phenomenon known as the Warburg effect. The maintenance of this mixed metabolic phenotype is seemingly counterintuitive given that aerobic glycolysis is far less efficient in terms of ATP yield per moles of glucose than mitochondrial respiration. Here, we resolve this apparent contradiction by expanding the notion of metabolic efficiency. We study a reduced flux balance model of ATP production that is constrained by the glucose uptake capacity and by the solvent capacity of the cell's cytoplasm, the latter quantifying the maximum amount of macromolecules that can occupy the intracellular space. At low glucose uptake rates we find that mitochondrial respiration is indeed the most efficient pathway for ATP generation. Above a threshold glucose uptake rate, however, a gradual activation of aerobic glycolysis and slight decrease of mitochondrial respiration results in the highest rate of ATP production. Our analyses indicate that the Warburg effect is a favorable catabolic state for all rapidly proliferating mammalian cells with high glucose uptake capacity. It arises because while aerobic glycolysis is less efficient than mitochondrial respiration in terms of ATP yield per glucose uptake, it is more efficient in terms of the required solvent capacity. These results may have direct relevance to chemotherapeutic strategies attempting to target cancer metabolism.

A Study on the Fundamental Mechanism and the Evolutionary Driving Forces behind Aerobic Fermentation in Yeast

PubMed Central

Hagman, Arne; Piškur, Jure

2015-01-01

Baker’s yeast Saccharomyces cerevisiae rapidly converts sugars to ethanol and carbon dioxide at both anaerobic and aerobic conditions. The later phenomenon is called Crabtree effect and has been described in two forms, long-term and short-term effect. We have previously studied under fully controlled aerobic conditions forty yeast species for their central carbon metabolism and the presence of long-term Crabtree effect. We have also studied ten steady-state yeast cultures, pulsed them with glucose, and followed the central carbon metabolism and the appearance of ethanol at dynamic conditions. In this paper we analyzed those wet laboratory data to elucidate possible mechanisms that determine the fate of glucose in different yeast species that cover approximately 250 million years of evolutionary history. We determine overflow metabolism to be the fundamental mechanism behind both long- and short-term Crabtree effect, which originated approximately 125–150 million years ago in the Saccharomyces lineage. The “invention” of overflow metabolism was the first step in the evolution of aerobic fermentation in yeast. It provides a general strategy to increase energy production rates, which we show is positively correlated to growth. The “invention” of overflow has also simultaneously enabled rapid glucose consumption in yeast, which is a trait that could have been selected for, to “starve” competitors in nature. We also show that glucose repression of respiration is confined mainly among S. cerevisiae and closely related species that diverged after the whole genome duplication event, less than 100 million years ago. Thus, glucose repression of respiration was apparently “invented” as a second step to further increase overflow and ethanol production, to inhibit growth of other microbes. The driving force behind the initial evolutionary steps was most likely competition with other microbes to faster consume and convert sugar into biomass, in niches that

A study on the fundamental mechanism and the evolutionary driving forces behind aerobic fermentation in yeast.

PubMed

Hagman, Arne; Piškur, Jure

2015-01-01

Baker's yeast Saccharomyces cerevisiae rapidly converts sugars to ethanol and carbon dioxide at both anaerobic and aerobic conditions. The later phenomenon is called Crabtree effect and has been described in two forms, long-term and short-term effect. We have previously studied under fully controlled aerobic conditions forty yeast species for their central carbon metabolism and the presence of long-term Crabtree effect. We have also studied ten steady-state yeast cultures, pulsed them with glucose, and followed the central carbon metabolism and the appearance of ethanol at dynamic conditions. In this paper we analyzed those wet laboratory data to elucidate possible mechanisms that determine the fate of glucose in different yeast species that cover approximately 250 million years of evolutionary history. We determine overflow metabolism to be the fundamental mechanism behind both long- and short-term Crabtree effect, which originated approximately 125-150 million years ago in the Saccharomyces lineage. The "invention" of overflow metabolism was the first step in the evolution of aerobic fermentation in yeast. It provides a general strategy to increase energy production rates, which we show is positively correlated to growth. The "invention" of overflow has also simultaneously enabled rapid glucose consumption in yeast, which is a trait that could have been selected for, to "starve" competitors in nature. We also show that glucose repression of respiration is confined mainly among S. cerevisiae and closely related species that diverged after the whole genome duplication event, less than 100 million years ago. Thus, glucose repression of respiration was apparently "invented" as a second step to further increase overflow and ethanol production, to inhibit growth of other microbes. The driving force behind the initial evolutionary steps was most likely competition with other microbes to faster consume and convert sugar into biomass, in niches that were semi-anaerobic.

Viral Activation of Cellular Metabolism

PubMed Central

Sanchez, Erica L.; Lagunoff, Michael

2015-01-01

To ensure optimal environments for their replication and spread, viruses have evolved to alter many host cell pathways. In the last decade, metabolomic studies have shown that eukaryotic viruses induce large-scale alterations in host cellular metabolism. Most viruses examined to date induce aerobic glycolysis also known as the Warburg effect. Many viruses tested also induce fatty acid synthesis as well as glutaminolysis. These modifications of carbon source utilization by infected cells can increase available energy for virus replication and virion production, provide specific cellular substrates for virus particles and create viral replication niches while increasing infected cell survival. Each virus species also likely requires unique metabolic changes for successful spread and recent research has identified additional virus-specific metabolic changes induced by many virus species. A better understanding of the metabolic alterations required for each virus may lead to novel therapeutic approaches through targeted inhibition of specific cellular metabolic pathways. PMID:25812764

Spruce Budworm and Energy Metabolism?

Treesearch

Thakor R.  Patel

1983-01-01

The utilization of stored lipids (fat) for energy metabolism appears to be a fundamental process for many biological systems especially during the early stages of their development. The participation of the glyoxylate cycle (GOG) together with other metabolic sequences like gluconeogenesis and beta oxidation are necessary for the conversion of lipids to carbohydrates....

Cardiovascular responses to rowing on a novel ergometer designed for both resistance and aerobic training in space.

PubMed

Tesch, Per A; Pozzo, Marco; Ainegren, Mats; Swarén, Mikael; Linnehan, Richard M

2013-05-01

Astronauts are required to perform both resistance and aerobic exercise while in orbit. This study assessed the aerobic energy yield and related physiological measurements using a nongravity dependent flywheel device designed for both resistance and aerobic exercise (RAD) in space. Eight physically active men and women performed all-out rowing on the RAD. For comparison, exercise was also carried out employing a commercially available rowing ergometer (C2). Peak oxygen uptake during exercise using RAD and C2 averaged 3.11 +/- 0.49 and 3.18 +/- 0.50 L x min(-1), respectively. Similarly, peak plasma lactate concentration (9.6 vs. 11.2 mmol x L(-1)), heart rate (183 vs. 184 bpm), and rate of perceived exertion (15.8 vs. 16.0) were comparable across exercise using the two devices. Collectively, the results suggest that this novel exercise modality offers cardiovascular and metabolic responses, and thus aerobic exercise stimulus that is equally effective as that evoked by established technology for indoor rowing. Given the need for physiologically sound and highly effective exercise countermeasures that features small mass and envelope, and allows for resistance and aerobic exercise in a single apparatus, we believe this novel hardware should be considered for use in space.

Links between metabolism and cancer

PubMed Central

Dang, Chi V.

2012-01-01

Metabolism generates oxygen radicals, which contribute to oncogenic mutations. Activated oncogenes and loss of tumor suppressors in turn alter metabolism and induce aerobic glycolysis. Aerobic glycolysis or the Warburg effect links the high rate of glucose fermentation to cancer. Together with glutamine, glucose via glycolysis provides the carbon skeletons, NADPH, and ATP to build new cancer cells, which persist in hypoxia that in turn rewires metabolic pathways for cell growth and survival. Excessive caloric intake is associated with an increased risk for cancers, while caloric restriction is protective, perhaps through clearance of mitochondria or mitophagy, thereby reducing oxidative stress. Hence, the links between metabolism and cancer are multifaceted, spanning from the low incidence of cancer in large mammals with low specific metabolic rates to altered cancer cell metabolism resulting from mutated enzymes or cancer genes. PMID:22549953

Aerobic Degradation of N-Methyl-4-Nitroaniline (MNA) by Pseudomonas sp. Strain FK357 Isolated from Soil

PubMed Central

Khan, Fazlurrahman; Vyas, Bhawna; Pal, Deepika; Cameotra, Swaranjit Singh

2013-01-01

N-Methyl-4-nitroaniline (MNA) is used as an additive to lower the melting temperature of energetic materials in the synthesis of insensitive explosives. Although the biotransformation of MNA under anaerobic condition has been reported, its aerobic microbial degradation has not been documented yet. A soil microcosms study showed the efficient aerobic degradation of MNA by the inhabitant soil microorganisms. An aerobic bacterium, Pseudomonas sp. strain FK357, able to utilize MNA as the sole carbon, nitrogen, and energy source, was isolated from soil microcosms. HPLC and GC-MS analysis of the samples obtained from growth and resting cell studies showed the formation of 4-nitroaniline (4-NA), 4-aminophenol (4-AP), and 1, 2, 4-benzenetriol (BT) as major metabolic intermediates in the MNA degradation pathway. Enzymatic assay carried out on cell-free lysates of MNA grown cells confirmed N-demethylation reaction is the first step of MNA degradation with the formation of 4-NA and formaldehyde products. Flavin-dependent transformation of 4-NA to 4-AP in cell extracts demonstrated that the second step of MNA degradation is a monooxygenation. Furthermore, conversion of 4-AP to BT by MNA grown cells indicates the involvement of oxidative deamination (release of NH2 substituent) reaction in third step of MNA degradation. Subsequent degradation of BT occurs by the action of benzenetriol 1, 2-dioxygenase as reported for the degradation of 4-nitrophenol. This is the first report on aerobic degradation of MNA by a single bacterium along with elucidation of metabolic pathway. PMID:24116023

Aerobic degradation of N-methyl-4-nitroaniline (MNA) by Pseudomonas sp. strain FK357 isolated from soil.

PubMed

Khan, Fazlurrahman; Vyas, Bhawna; Pal, Deepika; Cameotra, Swaranjit Singh

2013-01-01

N-Methyl-4-nitroaniline (MNA) is used as an additive to lower the melting temperature of energetic materials in the synthesis of insensitive explosives. Although the biotransformation of MNA under anaerobic condition has been reported, its aerobic microbial degradation has not been documented yet. A soil microcosms study showed the efficient aerobic degradation of MNA by the inhabitant soil microorganisms. An aerobic bacterium, Pseudomonas sp. strain FK357, able to utilize MNA as the sole carbon, nitrogen, and energy source, was isolated from soil microcosms. HPLC and GC-MS analysis of the samples obtained from growth and resting cell studies showed the formation of 4-nitroaniline (4-NA), 4-aminophenol (4-AP), and 1, 2, 4-benzenetriol (BT) as major metabolic intermediates in the MNA degradation pathway. Enzymatic assay carried out on cell-free lysates of MNA grown cells confirmed N-demethylation reaction is the first step of MNA degradation with the formation of 4-NA and formaldehyde products. Flavin-dependent transformation of 4-NA to 4-AP in cell extracts demonstrated that the second step of MNA degradation is a monooxygenation. Furthermore, conversion of 4-AP to BT by MNA grown cells indicates the involvement of oxidative deamination (release of NH2 substituent) reaction in third step of MNA degradation. Subsequent degradation of BT occurs by the action of benzenetriol 1, 2-dioxygenase as reported for the degradation of 4-nitrophenol. This is the first report on aerobic degradation of MNA by a single bacterium along with elucidation of metabolic pathway.

Molecular chaperone TRAP1 regulates a metabolic switch between mitochondrial respiration and aerobic glycolysis

PubMed Central

Yoshida, Soichiro; Tsutsumi, Shinji; Muhlebach, Guillaume; Sourbier, Carole; Lee, Min-Jung; Lee, Sunmin; Vartholomaiou, Evangelia; Tatokoro, Manabu; Beebe, Kristin; Miyajima, Naoto; Mohney, Robert P.; Chen, Yang; Hasumi, Hisashi; Xu, Wanping; Fukushima, Hiroshi; Nakamura, Ken; Koga, Fumitaka; Kihara, Kazunori; Trepel, Jane; Picard, Didier; Neckers, Leonard

2013-01-01

TRAP1 (TNF receptor-associated protein), a member of the HSP90 chaperone family, is found predominantly in mitochondria. TRAP1 is broadly considered to be an anticancer molecular target. However, current inhibitors cannot distinguish between HSP90 and TRAP1, making their utility as probes of TRAP1-specific function questionable. Some cancers express less TRAP1 than do their normal tissue counterparts, suggesting that TRAP1 function in mitochondria of normal and transformed cells is more complex than previously appreciated. We have used TRAP1-null cells and transient TRAP1 silencing/overexpression to show that TRAP1 regulates a metabolic switch between oxidative phosphorylation and aerobic glycolysis in immortalized mouse fibroblasts and in human tumor cells. TRAP1-deficiency promotes an increase in mitochondrial respiration and fatty acid oxidation, and in cellular accumulation of tricarboxylic acid cycle intermediates, ATP and reactive oxygen species. At the same time, glucose metabolism is suppressed. TRAP1-deficient cells also display strikingly enhanced invasiveness. TRAP1 interaction with and regulation of mitochondrial c-Src provide a mechanistic basis for these phenotypes. Taken together with the observation that TRAP1 expression is inversely correlated with tumor grade in several cancers, these data suggest that, in some settings, this mitochondrial molecular chaperone may act as a tumor suppressor. PMID:23564345

Sodium signaling and astrocyte energy metabolism.

PubMed

Chatton, Jean-Yves; Magistretti, Pierre J; Barros, L Felipe

2016-10-01

The Na(+) gradient across the plasma membrane is constantly exploited by astrocytes as a secondary energy source to regulate the intracellular and extracellular milieu, and discard waste products. One of the most prominent roles of astrocytes in the brain is the Na(+) -dependent clearance of glutamate released by neurons during synaptic transmission. The intracellular Na(+) load collectively generated by these processes converges at the Na,K-ATPase pump, responsible for Na(+) extrusion from the cell, which is achieved at the expense of cellular ATP. These processes represent pivotal mechanisms enabling astrocytes to increase the local availability of metabolic substrates in response to neuronal activity. This review presents basic principles linking the intracellular handling of Na(+) following activity-related transmembrane fluxes in astrocytes and the energy metabolic pathways involved. We propose a role of Na(+) as an energy currency and as a mediator of metabolic signals in the context of neuron-glia interactions. We further discuss the possible impact of the astrocytic syncytium for the distribution and coordination of the metabolic response, and the compartmentation of these processes in cellular microdomains and subcellular organelles. Finally, we illustrate future avenues of investigation into signaling mechanisms aimed at bridging the gap between Na(+) and the metabolic machinery. GLIA 2016;64:1667-1676. © 2016 Wiley Periodicals, Inc.

Metabolic consequences of resistive-type exercise

NASA Technical Reports Server (NTRS)

Dudley, G. A.

1988-01-01

This brief review concerns acute and chronic metabolic responses to resistive-type exercise (RTE) (i.e., Olympic/power weight lifting and bodybuilding). Performance of RTE presents power output substantially greater (10-15-fold) than that evident with endurance-type exercise. Accordingly, RTE relies heavily on the anaerobic enzyme machinery of skeletal muscle for energy supply, with alterations in the rate of aerobic metabolism being modest. Hydrolysis of high energy phosphate compounds (PC, ATP), glycogenolysis, and glycolysis are evident during an acute bout of RTE as indicated by metabolic markers in mixed fiber type skeletal muscle samples. The type of RTE probably influences the magnitude of these responses since the increase in blood lactate is much greater during a typical "bodybuilding" than "power lifting" session. The influence of RTE training on acute metabolic responses to RTE has received little attention. An individual's inherent metabolic characteristics are apparently sufficient to meet the energy demands of RTE as training of this type does not increase VO2max or substantially alter the content of marker enzymes in mixed fiber type skeletal muscle. Analyses of pools of fast- vs slow-twitch fibers, however, indicate that RTE-induced changes may be fiber type specific. Future studies should better delineate the metabolic responses to RTE and determine whether these are related to the enhanced performance associated with such training.

Aerobic Growth on Nitroglycerin as the Sole Carbon, Nitrogen, and Energy Source by a Mixed Bacterial Culture

PubMed Central

Accashian, John V.; Vinopal, Robert T.; Kim, Byung-Joon; Smets, Barth F.

1998-01-01

Nitroglycerin (glycerol trinitrate [GTN]), an explosive and vasodilatory compound, was metabolized by mixed microbial cultures from aeration tank sludge previously exposed to GTN. Aerobic enrichment cultures removed GTN rapidly in the absence of a supplemental carbon source. Complete denitration of GTN, provided as the sole C and N source, was observed in aerobic batch cultures and proceeded stepwise via the dinitrate and mononitrate isomers, with successive steps occurring at lower rates. The denitration of all glycerol nitrate esters was found to be concomitant, and 1,2-glycerol dinitrate (1,2-GDN) and 2-glycerol mononitrate (2-GMN) were the primary GDN and GMN isomers observed. Denitration of GTN resulted in release of primarily nitrite-N, indicating a reductive denitration mechanism. Biomass growth at the expense of GTN was verified by optical density and plate count measurements. The kinetics of GTN biotransformation were 10-fold faster than reported for complete GTN denitration under anaerobic conditions. A maximum specific growth rate of 0.048 ± 0.005 h−1 (mean ± standard deviation) was estimated for the mixed culture at 25°C. Evidence of GTN toxicity was observed at GTN concentrations above 0.3 mM. To our knowledge, this is the first report of complete denitration of GTN used as a primary growth substrate by a bacterial culture under aerobic conditions. PMID:9726874

Metabolism as a tool for understanding human brain evolution: lipid energy metabolism as an example.

PubMed

Wang, Shu Pei; Yang, Hao; Wu, Jiang Wei; Gauthier, Nicolas; Fukao, Toshiyuki; Mitchell, Grant A

2014-12-01

Genes and the environment both influence the metabolic processes that determine fitness. To illustrate the importance of metabolism for human brain evolution and health, we use the example of lipid energy metabolism, i.e. the use of fat (lipid) to produce energy and the advantages that this metabolic pathway provides for the brain during environmental energy shortage. We briefly describe some features of metabolism in ancestral organisms, which provided a molecular toolkit for later development. In modern humans, lipid energy metabolism is a regulated multi-organ pathway that links triglycerides in fat tissue to the mitochondria of many tissues including the brain. Three important control points are each suppressed by insulin. (1) Lipid reserves in adipose tissue are released by lipolysis during fasting and stress, producing fatty acids (FAs) which circulate in the blood and are taken up by cells. (2) FA oxidation. Mitochondrial entry is controlled by carnitine palmitoyl transferase 1 (CPT1). Inside the mitochondria, FAs undergo beta oxidation and energy production in the Krebs cycle and respiratory chain. (3) In liver mitochondria, the 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) pathway produces ketone bodies for the brain and other organs. Unlike most tissues, the brain does not capture and metabolize circulating FAs for energy production. However, the brain can use ketone bodies for energy. We discuss two examples of genetic metabolic traits that may be advantageous under most conditions but deleterious in others. (1) A CPT1A variant prevalent in Inuit people may allow increased FA oxidation under nonfasting conditions but also predispose to hypoglycemic episodes. (2) The thrifty genotype theory, which holds that energy expenditure is efficient so as to maximize energy stores, predicts that these adaptations may enhance survival in periods of famine but predispose to obesity in modern dietary environments. Copyright © 2014 Elsevier Ltd. All rights reserved.

Extra-mitochondrial aerobic metabolism in retinal rod outer segments: new perspectives in retinopathies.

PubMed

Panfoli, I; Calzia, D; Ravera, S; Morelli, A M; Traverso, C E

2012-04-01

Vertebrate retinal rods are photoreceptors for dim-light vision. They display extreme sensitivity to light thanks to a specialized subcellular organelle, the rod outer segment. This is filled with a stack of membranous disks, expressing the proteins involved in visual transduction, a very energy demanding process. Our previous proteomic and biochemical studies have shed new light on the chemical energy processes that supply ATP to the outer segment, suggesting the presence of an extra-mitochondrial aerobic metabolism in rod outer segment, devoid of mitochondria, which would account for a quantitatively adequate ATP supply for phototransduction. Here the functional presence of an oxidative phosphorylation in the rod outer limb is examined for its relationship to many physiological and pathological data on the rod outer segment. We hypothesize that the rod outer limb is at risk of oxidative stress, in any case of impairment in the respiratory chain functioning, or of blood supply. In fact, the electron transfer chain is a major source of reactive O(2) species, known to produce severe alteration to the membrane lipids, especially those of the outer segment that are rich in polyunsaturated fatty acids. We propose that the disk membrane may become the target of reactive oxygen species that may be released by the electron transport chain under pathologic conditions. For example, during aging reactive oxygen species production increases, while cellular antioxidant capacity decreases. Also the apoptosis of the rod observed after exposure to bright or continuous illumination can be explained considering that an overfunctioning of phototransduction may damage the disk membrane to a point at which cytochrome c escapes from the intradiskal space, where it is presently supposed to be, activating a putative caspase 9 and the apoptosome. A pathogenic mechanism for many inherited and acquired retinal degenerations, representing a major problem in clinical ophthalmology, is

Protons and pleomorphs: aerobic hydrogen production in Azotobacters.

PubMed

Noar, Jesse D; Bruno-Bárcena, José M

2016-02-01

As obligate aerobic soil organisms, the ability of Azotobacter species to fix nitrogen is unusual given that the nitrogenase complex requires a reduced cellular environment. Molecular hydrogen is an unavoidable byproduct of the reduction of dinitrogen; at least one molecule of H2 is produced for each molecule of N2 fixed. This could be considered a fault in nitrogenase efficiency, essentially a waste of energy and reducing equivalents. Wild-type Azotobacter captures this hydrogen and oxidizes it with its membrane-bound uptake hydrogenase complex. Strains lacking an active hydrogenase complex have been investigated for their hydrogen production capacities. What is the role of H2 in the energy metabolism of nitrogen-fixing Azotobacter? Is hydrogen production involved in Azotobacter species' protection from or tolerance to oxygen, or vice versa? What yields of hydrogen can be expected from hydrogen-evolving strains? Can the yield of hydrogen be controlled or increased by changing genetic, environmental, or physiological conditions? We will address these questions in the following mini-review.

SYNAPTOSOMAL LACTATE DEHYDROGENASE ISOENZYME COMPOSITION IS SHIFTED TOWARD AEROBIC FORMS IN PRIMATE BRAIN EVOLUTION

PubMed Central

Duka, Tetyana; Anderson, Sarah M.; Collins, Zachary; Raghanti, Mary Ann; Ely, John J.; Hof, Patrick R.; Wildman, Derek E.; Goodman, Morris; Grossman, Lawrence I.; Sherwood, Chet C.

2014-01-01

With the evolution of a relatively large brain size in haplorhine primates (i.e., tarsiers, monkeys, apes and humans), there have been associated changes in the molecular machinery that delivers energy to the neocortex. Here we investigated variation in lactate dehydrogenase (LDH) expression and isoenzyme composition of the neocortex and striatum in primates using quantitative Western blotting and isoenzyme analysis of total homogenates and synaptosomal fractions. Analysis of isoform expression revealed that LDH in the synaptosomal fraction from both forebrain regions shifted towards a predominance of the heart-type, aerobic isoforms, LDHB, among haplorhines as compared to strepsirrhines (i.e., lorises and lemurs), while in total homogenate of neocortex and striatum there was no significant difference in the LDH isoenzyme composition between the primate suborders. The largest increase occurred in synapse-associated LDH-B expression in the neocortex, displaying an especially remarkable elevation in the ratio of LDH-B to LDH-A in humans. The phylogenetic variation in LDH-B to LDH-A ratio was correlated with species typical brain mass, but not encephalization quotient. A significant LDHB increase in the sub-neuronal fraction from haplorhine neocortex and striatum suggests a relatively higher rate of aerobic glycolysis that is linked to synaptosomal mitochondrial metabolism. Our results indicate that there is differential composition of LDH isoenzymes and metabolism in synaptic terminals that evolved in primates to meet increased energy requirements in association with brain enlargement. PMID:24686273

Metabolic and hormonal changes during aerobic exercise in distance runners.

PubMed

Fernández-Pastor, V J; Ruiz, M; Diego-Acosta, A M; Avila, C; García, J C; Pérez, F; Guirado, F; Noguer, N

1999-03-01

A group of long-distance runners is studied in order to clarify aspects concerning neuroendocrine mechanisms regulating organic adaptation to maximum effort, with special interest in the function of the growth hormone in fat metabolism and the possible use of ketone bodies as an alternative source of energy. A test is designed on a treadmill with a gradient of 3% and progressive increases in speed of 2 Km/h every 10 min, starting at 6 Km/h, and continuing until exhaustion. Masks are worn to enable the breath by breath measurement of expired gases and the subjects are monitored electrocardiographically using V5. For blood sample collection an antecubital vein is catheterized with a system enabling the replacement of the blood volume extracted by means of perfusion with physiological saline solution, and the increasing concentration of hormones in the blood is evaluated. The results obtained, indicate that epinephrine as well as GH hormones increase significatively from 20 min of exercise in runners promoting changes from carbohydrates to lipids as fuels to carry out exercise. The concomitant variations in energy substrates support the former hypothesis of work. Moreover, the muscle could employ acetylCoA originating from acetoacetate as an alternative metabolic source of fuel during maximum effort.

Modelling chronotaxicity of cellular energy metabolism to facilitate the identification of altered metabolic states

NASA Astrophysics Data System (ADS)

Lancaster, Gemma; Suprunenko, Yevhen F.; Jenkins, Kirsten; Stefanovska, Aneta

2016-08-01

Altered cellular energy metabolism is a hallmark of many diseases, one notable example being cancer. Here, we focus on the identification of the transition from healthy to abnormal metabolic states. To do this, we study the dynamics of energy production in a cell. Due to the thermodynamic openness of a living cell, the inability to instantaneously match fluctuating supply and demand in energy metabolism results in nonautonomous time-varying oscillatory dynamics. However, such oscillatory dynamics is often neglected and treated as stochastic. Based on experimental evidence of metabolic oscillations, we show that changes in metabolic state can be described robustly by alterations in the chronotaxicity of the corresponding metabolic oscillations, i.e. the ability of an oscillator to resist external perturbations. We also present a method for the identification of chronotaxicity, applicable to general oscillatory signals and, importantly, apply this to real experimental data. Evidence of chronotaxicity was found in glycolytic oscillations in real yeast cells, verifying that chronotaxicity could be used to study transitions between metabolic states.

Role of Gts1p in regulation of energy-metabolism oscillation in continuous cultures of the yeast Saccharomyces cerevisiae.

PubMed

Xu, Zhaojun; Tsurugi, Kunio

2007-03-01

Energy-metabolism oscillation (EMO) in an aerobic chemostat culture of yeast is basically regulated by a feedback loop of redox reactions in energy metabolism and modulated by metabolism of storage carbohydrates. In this study, we investigated the role of Gts1p in the stabilization of EMO, using the GTS1-deleted transformant gts1Delta. We found that fluctuations in the redox state of the NAD co-factor and levels of redox-regulated metabolites in glycolysis, especially of ethanol, are markedly reduced in amplitude during EMO of gts1Delta, while respiration indicated by the oxygen uptake rate (OUR) and energy charge is not so affected throughout EMO in gts1Delta. Further, the transitions of the levels of OUR, NAD(+) : NADH ratio and intracellular pH between the two phases were apparently retarded compared with those in the wild-type, suggesting attenuation of EMO in gts1Delta. Furthermore, the mRNA levels of genes encoding enzymes for the synthesis of trehalose and glycogen are fairly reduced in gts1Delta, consistent with the decreased synthesis of storage carbohydrates. In addition, the level of inorganic phosphate, which is required for the reduction of NAD(+) and mainly supplied from trehalose synthesis, was decreased in the early respiro-fermentative phase in gts1Delta. Thus, we suggested that the deletion of GTS1 as a transcriptional co-activator for these genes inhibited the metabolism of storage carbohydrates, which causes attenuation of the feedback loop of dehydrogenase reactions in glycolysis with the restricted fluctuation of ethanol as a main synchronizing agent for EMO in a cell population.

[Moderately haloalkaliphilic aerobic methylobacteria].

PubMed

Trotsenko, Iu A; Doronina, N V; Li, Ts D; Reshetnikov, A S

2007-01-01

Aerobic methylobacteria utilizing oxidized and substituted methane derivatives as carbon and energy sources are widespread in nature and involved in the global carbon cycle, being a unique biofilter on the path of these C1 compounds from different ecosystems to the atmosphere. New data on the biological features of moderately halophilic, neutrophilic, and alkaliphilic methylobacteria isolated from biotopes with higher osmolarity (seas, saline and soda lakes, saline soils, and deteriorating marble) are reviewed. Particular attention is paid to the latest advances in the study of the mechanisms of osmoadaptation of aerobic moderately haloalkaliphilic methylobacteria: formation of osmolytes, in particular, molecular and genetic aspects of biosynthesis of the universal bioprotectant ectoine. The prospects for further studies of the physiological and biochemical principles of haloalkalophily and for the application of haloalkaliphilic aerobic methylobacteria in biosynthesis and biodegradation are discussed.

Anaerobic digestion of dairy cattle manure autoheated by aerobic pretreatment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Achkari-Begdouri, A.

1989-01-01

A novel way to heat anaerobic digesters was investigated. Dairy cattle manure was autoheated by an aerobic pretreatment process and then fed to the anaerobic digester. Important physical properties of the dairy cattle manure were determined. These included bulk density, specific heat, thermal conductivity and the rheological properties; consistency coefficient, behavior index and apparent viscosity. These parameters were used to calculate the overall heat transfer coefficients, and to estimate the heat losses from the aerobic reactor to the outside environment. The total energy balance of the aerobic treatment system was then established. An optimization study of the main parameters influencingmore » the autoheating process showed that the total solids, the air flow rate and the stirring speed for operation of the aerobic pretreatment should be approximately 7%, 70 L/H and 1,400 rpm respectively. Temperatures as high as 65C were reached in 40 hours of aerobic treatment. At the above recommended levels of total solids, the air flow rate and the stirring speed, there was little difference in the energy requirements for heating the influent by aeration and heating the influent by a conventional heating system. In addition to the temperature increase, the aerobic pretreatment assisted in balancing the anaerobic digestion process and increased the methanogenesis of the dairy cattle manure. Despite the 8% decomposition of organic matter that occurred during the aerobic pretreatment process, methane production of the digester started with the aerobically heated manure was significantly higher (at least 20% higher) than of the digester started with conventionally heated manure. The aerobic system successfully autoheated the dairy cattle manure with an energy cost equal to that of conventionally heated influent.« less

Vampires, Pasteur and reactive oxygen species. Is the switch from aerobic to anaerobic metabolism a preventive antioxidant defence in blood-feeding parasites?

PubMed

Oliveira, Pedro L; Oliveira, Marcus F

2002-08-14

Several species of parasites show a reduction of their respiratory activity along their developmental cycles after they start to feed on vertebrate blood, relying on anaerobic degradation of carbohydrates to achieve their energy requirements. Usually, these parasites choose not to breathe despite of living in an environment of high oxygen availability such as vertebrate blood. Absence of the 'Pasteur effect' in most of these parasites has been well documented. Interestingly, together with the switch from aerobic to anaerobic metabolism in these parasites, there is clear evidence pointing to an increase in their antioxidant defences. As the respiratory chain in mitochondria is a major site of production of reactive oxygen species (ROS), we propose here that the arrest of respiration constitutes an adaptation to avoid the toxic effects of ROS. This situation would be especially critical for blood-feeding parasites because ROS produced in mitochondria would interact with pro-oxidant products of blood digestion, such as haem and/or iron, and increase the oxidative damage to the parasite's cells.

Aerobic biodegradation of trichloroethene without auxiliary substrates.

PubMed

Schmidt, Kathrin R; Gaza, Sarah; Voropaev, Andrey; Ertl, Siegmund; Tiehm, Andreas

2014-08-01

Trichloroethene (TCE) represents a priority pollutant and is among the most frequently detected contaminants in groundwater. The current bioremediation measures have certain drawbacks like e.g. the need for auxiliary substrates. Here, the aerobic biodegradation of TCE as the sole growth substrate is demonstrated. This new process of metabolic TCE degradation was first detected in groundwater samples. TCE degradation was stable in an enriched mixed bacterial culture in mineral salts medium for over five years and repeated transfers of the culture resulting in a 10(10) times dilution of the original groundwater. Aerobic TCE degradation resulted in stoichiometric chloride formation. Stable carbon isotope fractionation was observed providing a reliable analytical tool to assess this new biodegradation process at field sites. The results suggest that aerobic biodegradation of TCE without auxiliary substrate could be considered as an option for natural attenuation or engineered bioremediation of contaminated sites. Copyright © 2014 Elsevier Ltd. All rights reserved.

Four birds with one stone? Reparative, neuroplastic, cardiorespiratory, and metabolic benefits of aerobic exercise poststroke.

PubMed

Ploughman, Michelle; Kelly, Liam P

2016-12-01

Converging evidence from animal models of stroke and clinical trials suggests that aerobic exercise has effects across multiple targets. The subacute phase is characterized by a period of heightened neuroplasticity when aerobic exercise has the potential to optimize recovery. In animals, low intensity aerobic exercise shrinks lesion size and reduces cell death and inflammation, beginning 24 h poststroke. Also in animals, aerobic exercise upregulates brain-derived neurotrophic factor near the lesion and improves learning. In terms of neuroplastic effects, clinical trial results are less convincing and have only examined effects in chronic stroke. Stroke patients demonstrate cardiorespiratory fitness levels below the threshold required to carry out daily activities. This may contribute to a 'neurorehabilitation ceiling' that limits capacity to practice at a high enough frequency and intensity to promote recovery. Aerobic exercise when delivered 2-5 days per week at moderate to high intensity beginning as early as 5 days poststroke improves cardiorespiratory fitness, dyslipidemia, and glucose tolerance. Based on the evidence discussed and applying principles of periodization commonly used to prepare athletes for competition, we have created a model of aerobic training in subacute stroke in which training is delivered in density blocks (duration × intensity) matched to recovery phases.

Microbial catabolic activities are naturally selected by metabolic energy harvest rate.

PubMed

González-Cabaleiro, Rebeca; Ofiţeru, Irina D; Lema, Juan M; Rodríguez, Jorge

2015-12-01

The fundamental trade-off between yield and rate of energy harvest per unit of substrate has been largely discussed as a main characteristic for microbial established cooperation or competition. In this study, this point is addressed by developing a generalized model that simulates competition between existing and not experimentally reported microbial catabolic activities defined only based on well-known biochemical pathways. No specific microbial physiological adaptations are considered, growth yield is calculated coupled to catabolism energetics and a common maximum biomass-specific catabolism rate (expressed as electron transfer rate) is assumed for all microbial groups. Under this approach, successful microbial metabolisms are predicted in line with experimental observations under the hypothesis of maximum energy harvest rate. Two microbial ecosystems, typically found in wastewater treatment plants, are simulated, namely: (i) the anaerobic fermentation of glucose and (ii) the oxidation and reduction of nitrogen under aerobic autotrophic (nitrification) and anoxic heterotrophic and autotrophic (denitrification) conditions. The experimentally observed cross feeding in glucose fermentation, through multiple intermediate fermentation pathways, towards ultimately methane and carbon dioxide is predicted. Analogously, two-stage nitrification (by ammonium and nitrite oxidizers) is predicted as prevailing over nitrification in one stage. Conversely, denitrification is predicted in one stage (by denitrifiers) as well as anammox (anaerobic ammonium oxidation). The model results suggest that these observations are a direct consequence of the different energy yields per electron transferred at the different steps of the pathways. Overall, our results theoretically support the hypothesis that successful microbial catabolic activities are selected by an overall maximum energy harvest rate.

Gut microbiota are linked to increased susceptibility to hepatic steatosis in low-aerobic-capacity rats fed an acute high-fat diet.

PubMed

Panasevich, Matthew R; Morris, E M; Chintapalli, S V; Wankhade, U D; Shankar, K; Britton, S L; Koch, L G; Thyfault, J P; Rector, R S

2016-07-01

Poor aerobic fitness is linked to nonalcoholic fatty liver disease and increased all-cause mortality. We previously found that rats with a low capacity for running (LCR) that were fed an acute high-fat diet (HFD; 45% kcal from fat) for 3 days resulted in positive energy balance and increased hepatic steatosis compared with rats that were highly aerobically fit with a high capacity for running (HCR). Here, we tested the hypothesis that poor physiological outcomes in LCR rats following acute HFD feeding are associated with alterations in cecal microbiota. LCR rats exhibited greater body weight, feeding efficiency, 3 days of body weight change, and liver triglycerides after acute HFD feeding compared with HCR rats. Furthermore, compared with HCR rats, LCR rats exhibited reduced expression of intestinal tight junction proteins. Cecal bacterial 16S rDNA revealed that LCR rats had reduced cecal Proteobacteria compared with HCR rats. Microbiota of HCR rats consisted of greater relative abundance of Desulfovibrionaceae and unassigned genera within this family, suggesting increased reduction of endogenous mucins and proteins. Although feeding rats an acute HFD led to reduced Firmicutes in both strains, short-chain fatty acid-producing Phascolarctobacterium was reduced in LCR rats. In addition, Ruminococcae and Ruminococcus were negatively correlated with energy intake in the LCR/HFD rats. Predicted metagenomic function suggested that LCR rats had a greater capacity to metabolize carbohydrate and energy compared with HCR rats. Overall, these data suggest that the populations and metabolic capacity of the microbiota in low-aerobically fit LCR rats may contribute to their susceptibility to acute HFD-induced hepatic steatosis and poor physiologic outcomes.

Gut microbiota are linked to increased susceptibility to hepatic steatosis in low-aerobic-capacity rats fed an acute high-fat diet

PubMed Central

Panasevich, Matthew R.; Morris, E. M.; Chintapalli, S. V.; Wankhade, U. D.; Shankar, K.; Britton, S. L.; Koch, L. G.; Thyfault, J. P.

2016-01-01

Poor aerobic fitness is linked to nonalcoholic fatty liver disease and increased all-cause mortality. We previously found that rats with a low capacity for running (LCR) that were fed an acute high-fat diet (HFD; 45% kcal from fat) for 3 days resulted in positive energy balance and increased hepatic steatosis compared with rats that were highly aerobically fit with a high capacity for running (HCR). Here, we tested the hypothesis that poor physiological outcomes in LCR rats following acute HFD feeding are associated with alterations in cecal microbiota. LCR rats exhibited greater body weight, feeding efficiency, 3 days of body weight change, and liver triglycerides after acute HFD feeding compared with HCR rats. Furthermore, compared with HCR rats, LCR rats exhibited reduced expression of intestinal tight junction proteins. Cecal bacterial 16S rDNA revealed that LCR rats had reduced cecal Proteobacteria compared with HCR rats. Microbiota of HCR rats consisted of greater relative abundance of Desulfovibrionaceae and unassigned genera within this family, suggesting increased reduction of endogenous mucins and proteins. Although feeding rats an acute HFD led to reduced Firmicutes in both strains, short-chain fatty acid-producing Phascolarctobacterium was reduced in LCR rats. In addition, Ruminococcae and Ruminococcus were negatively correlated with energy intake in the LCR/HFD rats. Predicted metagenomic function suggested that LCR rats had a greater capacity to metabolize carbohydrate and energy compared with HCR rats. Overall, these data suggest that the populations and metabolic capacity of the microbiota in low-aerobically fit LCR rats may contribute to their susceptibility to acute HFD-induced hepatic steatosis and poor physiologic outcomes. PMID:27288420

INSECT FAT BODY: ENERGY, METABOLISM, AND REGULATION

PubMed Central

Arrese, Estela L.; Soulages, Jose L.

2010-01-01

The fat body plays major roles in the life of insects. It is a dynamic tissue involved in multiple metabolic functions. One of these functions is to store and release energy in response to the energy demands of the insect. Insects store energy reserves in the form of glycogen and triglycerides in the adipocytes, the main fat body cell. Insect adipocytes can store a great amount of lipid reserves as cytoplasmic lipid droplets. Lipid metabolism is essential for growth and reproduction and provides energy needed during extended nonfeeding periods. This review focuses on energy storage and release and summarizes current understanding of the mechanisms underlying these processes in insects. PMID:19725772

Effects of catecholamines on rat myocardial metabolism. I. Influence of catecholamines on energy-rich nucleotides and phosphorylated fraction contents.

PubMed

Merouze, P; Gaudemer, Y

1975-01-01

1. The influence of catecholamines (adrenaline and noradrenaline) on energy metabolism of the rat myocardium has been studied by incubating slices of this tissue with these hormones and by following the levels of the different phosphorylated fractions and adenylic nucleotides. 2. Similar effects are obtained with both hormones, adrenaline being more effective. 3. Catecholamines decrease significantly the total amount of phosphate while Pi content increases during the first 10 minutes of incubation; labile and residual phosphate contents increase at the beginning of incubation and decrease to the initial values afterwards. 4. ATP and ADP levels decrease significantly with both hormones; however, the effect of noradrenalin on the ATP level needs a longer time of incubation. The ATP/ADP ratios decrease after 5 minutes incubation and the total adenylic nucleotide content is severely decreased (35 per cent with adrenalin, after 20 minutes incubation). 5. Similar results have been obtained with other tissues; these results can explain the decrease of aerobic metabolism we observed under the same conditions.

Teaching the basics of cancer metabolism: Developing antitumor strategies by exploiting the differences between normal and cancer cell metabolism.

PubMed

Kalyanaraman, Balaraman

2017-08-01

This review of the basics of cancer metabolism focuses on exploiting the metabolic differences between normal and cancer cells. The first part of the review covers the different metabolic pathways utilized in normal cells to generate cellular energy, or ATP, and the glycolytic intermediates required to build the cellular machinery. The second part of the review discusses aerobic glycolysis, or the Warburg effect, and the metabolic reprogramming involving glycolysis, tricarboxylic acid cycle, and glutaminolysis in the context of developing targeted inhibitors in cancer cells. Finally, the selective targeting of cancer mitochondrial metabolism using positively charged lipophilic compounds as potential therapeutics and their ability to mitigate the toxic side effects of conventional chemotherapeutics in normal cells are discussed. I hope this graphical review will be useful in helping undergraduate, graduate, and medical students understand how investigating the basics of cancer cell metabolism could provide new insight in developing potentially new anticancer treatment strategies. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Quantitative analysis of microbial biomass yield in aerobic bioreactor.

PubMed

Watanabe, Osamu; Isoda, Satoru

2013-12-01

We have studied the integrated model of reaction rate equations with thermal energy balance in aerobic bioreactor for food waste decomposition and showed that the integrated model has the capability both of monitoring microbial activity in real time and of analyzing biodegradation kinetics and thermal-hydrodynamic properties. On the other hand, concerning microbial metabolism, it was known that balancing catabolic reactions with anabolic reactions in terms of energy and electron flow provides stoichiometric metabolic reactions and enables the estimation of microbial biomass yield (stoichiometric reaction model). We have studied a method for estimating real-time microbial biomass yield in the bioreactor during food waste decomposition by combining the integrated model with the stoichiometric reaction model. As a result, it was found that the time course of microbial biomass yield in the bioreactor during decomposition can be evaluated using the operational data of the bioreactor (weight of input food waste and bed temperature) by the combined model. The combined model can be applied to manage a food waste decomposition not only for controlling system operation to keep microbial activity stable, but also for producing value-added products such as compost on optimum condition. Copyright © 2013 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

Early Postnatal Cardiomyocyte Proliferation Requires High Oxidative Energy Metabolism.

PubMed

de Carvalho, Ana Elisa Teófilo Saturi; Bassaneze, Vinícius; Forni, Maria Fernanda; Keusseyan, Aline Alfonso; Kowaltowski, Alicia Juliana; Krieger, José Eduardo

2017-11-13

Cardiac energy metabolism must cope with early postnatal changes in tissue oxygen tensions, hemodynamics, and cell proliferation to sustain development. Here, we tested the hypothesis that proliferating neonatal cardiomyocytes are dependent on high oxidative energy metabolism. We show that energy-related gene expression does not correlate with functional oxidative measurements in the developing heart. Gene expression analysis suggests a gradual overall upregulation of oxidative-related genes and pathways, whereas functional assessment in both cardiac tissue and cultured cardiomyocytes indicated that oxidative metabolism decreases between the first and seventh days after birth. Cardiomyocyte extracellular flux analysis indicated that the decrease in oxidative metabolism between the first and seventh days after birth was mostly related to lower rates of ATP-linked mitochondrial respiration, suggesting that overall energetic demands decrease during this period. In parallel, the proliferation rate was higher for early cardiomyocytes. Furthermore, in vitro nonlethal chemical inhibition of mitochondrial respiration reduced the proliferative capacity of early cardiomyocytes, indicating a high energy demand to sustain cardiomyocyte proliferation. Altogether, we provide evidence that early postnatal cardiomyocyte proliferative capacity correlates with high oxidative energy metabolism. The energy requirement decreases as the proliferation ceases in the following days, and both oxidative-dependent metabolism and anaerobic glycolysis subside.

The Combined Intervention with Germinated Vigna radiata and Aerobic Interval Training Protocol Is an Effective Strategy for the Treatment of Non-Alcoholic Fatty Liver Disease (NAFLD) and Other Alterations Related to the Metabolic Syndrome in Zucker Rats.

PubMed

Kapravelou, Garyfallia; Martínez, Rosario; Nebot, Elena; López-Jurado, María; Aranda, Pilar; Arrebola, Francisco; Cantarero, Samuel; Galisteo, Milagros; Porres, Jesus M

2017-07-19

Metabolic syndrome (MetS) is a group of related metabolic alterations that increase the risk of developing non-alcoholic fatty liver disease (NAFLD). Several lifestyle interventions based on dietary treatment with functional ingredients and physical activity are being studied as alternative or reinforcement treatments to the pharmacological ones actually in use. In the present experiment, the combined treatment with mung bean ( Vigna radiata ), a widely used legume with promising nutritional and health benefits that was included in the experimental diet as raw or 4 day-germinated seed flour, and aerobic interval training protocol (65-85% VO₂ max) has been tested in lean and obese Zucker rats following a 2 × 2 × 2 (2 phenotypes, 2 dietary interventions, 2 lifestyles) factorial ANOVA (Analysis of Variance) statistical analysis. Germination of V. radiata over a period of four days originated a significant protein hydrolysis leading to the appearance of low molecular weight peptides. The combination of 4 day-germinated V. radiata and aerobic interval training was more efficient compared to raw V. radiata at improving the aerobic capacity and physical performance, hepatic histology and functionality, and plasma lipid parameters as well as reverting the insulin resistance characteristic of the obese Zucker rat model. In conclusion, the joint intervention with legume sprouts and aerobic interval training protocol is an efficient treatment to improve the alterations of glucose and lipid metabolism as well as hepatic histology and functionality related to the development of NAFLD and the MetS.

Effects of intense aerobic exercise and/or antihypertensive medication in individuals with metabolic syndrome.

PubMed

Ramirez-Jimenez, M; Morales-Palomo, F; Ortega, J F; Mora-Rodriguez, R

2018-05-17

We studied the blood pressure lowering effects of a bout of exercise and/or antihypertensive medicine with the goal of studying if exercise could substitute or enhance pharmacologic hypertension treatment. Twenty-three hypertensive metabolic syndrome patients chronically medicated with angiotensin II receptor 1 blockade antihypertensive medicine underwent 24-hr monitoring in four separated days in a randomized order; a) after taking their habitual dose of antihypertensive medicine (AHM trial), b) substituting their medicine by placebo medicine (PLAC trial), c) placebo medicine with a morning bout of intense aerobic exercise (PLAC+EXER trial) and d) combining the exercise and antihypertensive medicine (AHM+EXER trial). We found that in trials with AHM subjects had lower plasma aldosterone/renin activity ratio evidencing treatment compliance. Before exercise, the trials with AHM displayed lower systolic (130±16 vs 133±15 mmHg; P=0.018) and mean blood pressures (94±11 vs 96±10 mmHg; P=0.036) than trials with placebo medication. Acutely (i.e., 30 min after treatments) combining AHM+EXER lowered systolic blood pressure (SBP) below the effects of PLAC+EXER (-8.1±1.6 vs -4.9±1.5 mmHg; P=0.015). Twenty-four hour monitoring revealed no differences among trials in body motion. However, PLAC+EXER and AHM lowered SBP below PLAC during the first 10 hours, time at which PLAC+EXER effects faded out (i.e., at 19 PM). Adding exercise to medication (i.e., AHM+EXER) resulted in longer reductions in SBP than with exercise alone (PLAC+EXER). In summary, one bout of intense aerobic exercise in the morning cannot substitute the long-lasting effects of antihypertensive medicine in lowering blood pressure, but their combination is superior to exercise alone. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Cardiac metabolism in the Myxinidae: physiological and phylogenetic considerations.

PubMed

Sidell, B D

1983-01-01

Cardiac muscle hearts of Atlantic hagfish continuously function under hypoxic conditions that would lead to cardiac failure in most other vertebrates. Contractile performance of hagfish systemic hearts is resistant to anoxia and respiratory poisons but shows a significant decrement when carbohydrate catabolism is blocked by 0.5 mM iodoacetic acid. Enzyme activity profiles of hagfish ventricle reveal a robust capacity for glycolysis of carbohydrate in comparison to that for general aerobic metabolism and catabolism of alternate metabolic fuels. Isolated working hagfish ventricles preferentially oxidize radiolabeled glucose even when fatty acid fuels are present in the incubation medium. Work output of the isolated ventricular preparation is maintained only in the presence of exogenous glucose. The results indicate that energy metabolism of the hagfish myocardium is predominantly carbohydrate-based and that energy demand of the tissue can be sustained by anaerobic glycolysis during extended periods of extreme hypoxia. Cardiac metabolism of this primitive species is compared with that of hearts from higher vertebrates and an evolutionary hypothesis relating cardiac workload to preferred metabolic fuel is discussed.

Sequential anaerobic/aerobic biodegradation of chloroethenes--aspects of field application.

PubMed

Tiehm, Andreas; Schmidt, Kathrin R

2011-06-01

Because of a range of different industrial activities, sites contaminated with chloroethenes are a world-wide problem. Chloroethenes can be biodegraded by reductive dechlorination under anaerobic conditions as well as by oxidation under aerobic conditions. The tendency of chloroethenes to undergo reductive dechlorination decreases with a decreasing number of chlorine substituents, whereas with less chlorine substituents chloroethenes more easily undergo oxidative degradation. There is currently a growing interest in aerobic metabolic degradation of chloroethenes, which demonstrates advantages compared to cometabolic degradation pathways. Sequential anaerobic/aerobic biodegradation can overcome the disadvantages of reductive dechlorination and leads to complete mineralization of the chlorinated pollutants. This approach shows promise for site remediation in natural settings and in engineered systems. Copyright © 2011 Elsevier Ltd. All rights reserved.

Cellular energy metabolism in T-lymphocytes.

PubMed

Gaber, Timo; Strehl, Cindy; Sawitzki, Birgit; Hoff, Paula; Buttgereit, Frank

2015-01-01

Energy homeostasis is a hallmark of cell survival and maintenance of cell function. Here we focus on the impact of cellular energy metabolism on T-lymphocyte differentiation, activation, and function in health and disease. We describe the role of transcriptional and posttranscriptional regulation of lymphocyte metabolism on immune functions of T cells. We also summarize the current knowledge about T-lymphocyte adaptations to inflammation and hypoxia, and the impact on T-cell behavior of pathophysiological hypoxia (as found in tumor tissue, chronically inflamed joints in rheumatoid arthritis and during bone regeneration). A better understanding of the underlying mechanisms that control immune cell metabolism and immune response may provide therapeutic opportunities to alter the immune response under conditions of either immunosuppression or inflammation, potentially targeting infections, vaccine response, tumor surveillance, autoimmunity, and inflammatory disorders.

Stable Isotope-Assisted Metabolic Profiling Reveals Growth Mode Dependent Differential Metabolism and Multiple Catabolic Pathways of l-Phenylalanine in Rubrivivax benzoatilyticus JA2.

PubMed

Mekala, Lakshmi Prasuna; Mohammed, Mujahid; Chintalapati, Sasikala; Chintalapati, Venkata Ramana

2018-01-05

Anoxygenic phototrophic bacteria are metabolically versatile and survive under different growth modes using diverse organic compounds, yet their metabolic diversity is largely unexplored. In the present study, we employed stable-isotope-assisted metabolic profiling to unravel the l-phenylalanine catabolism in Rubrivivax benzoatilyticus JA2 under varying growth modes. Strain JA2 grows under anaerobic and aerobic conditions by utilizing l-phenylalanine as a nitrogen source. Furthermore, ring-labeled 13 C 6 -phenylalanine feeding followed by liquid chromatography-mass spectrometry exometabolite profiling revealed 60 labeled metabolic features (M + 6, M + 12, and M + 18) derived solely from l-phenylalanine, of which 11 were identified, 7 putatively identified, and 42 unidentified under anaerobic and aerobic conditions. However, labeled metabolites were significantly higher in aerobic compared to anaerobic conditions. Furthermore, detected metabolites and enzyme activities indicated multiple l-phenylalanine catabolic routes mainly Ehrlich, homogentisate-dependent melanin, benzenoid, and unidentified pathways operating under anaerobic and aerobic conditions in strain JA2. Interestingly, the study indicated l-phenylalanine-dependent and independent benzenoid biosynthesis in strain JA2 and a differential flux of l-phenylalanine to Ehrlich and benzenoid pathways under anaerobic and aerobic conditions. Additionally, unidentified labeled metabolites strongly suggest the presence of unknown phenylalanine catabolic routes in strain JA2. Overall, the study uncovered the l-phenylalanine catabolic diversity in strain JA2 and demonstrated the potential of stable isotope-assisted metabolomics in unraveling the hidden metabolic repertoire.

Microglia energy metabolism in metabolic disorder.

PubMed

Kalsbeek, Martin J T; Mulder, Laurie; Yi, Chun-Xia

2016-12-15

Microglia are the resident macrophages of the CNS, and are in charge of maintaining a healthy microenvironment to ensure neuronal survival. Microglia carry out a non-stop patrol of the CNS, make contact with neurons and look for abnormalities, all of which requires a vast amount of energy. This non-signaling energy demand increases after activation by pathogens, neuronal damage or other kinds of stimulation. Of the three major energy substrates - glucose, fatty acids and glutamine - glucose is crucial for microglia survival and several glucose transporters are expressed to supply sufficient glucose influx. Fatty acids are another source of energy for microglia and have also been shown to strongly influence microglial immune activity. Glutamine, although possibly suitable for use as an energy substrate by microglia, has been shown to have neurotoxic effects when overloaded. Microglial fuel metabolism might be associated with microglial reactivity under different pathophysiological conditions and a microglial fuel switch may thus be the underlying cause of hypothalamic dysregulation, which is associated with obesity. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

A cellular perspective on brain energy metabolism and functional imaging.

PubMed

Magistretti, Pierre J; Allaman, Igor

2015-05-20

The energy demands of the brain are high: they account for at least 20% of the body's energy consumption. Evolutionary studies indicate that the emergence of higher cognitive functions in humans is associated with an increased glucose utilization and expression of energy metabolism genes. Functional brain imaging techniques such as fMRI and PET, which are widely used in human neuroscience studies, detect signals that monitor energy delivery and use in register with neuronal activity. Recent technological advances in metabolic studies with cellular resolution have afforded decisive insights into the understanding of the cellular and molecular bases of the coupling between neuronal activity and energy metabolism and point at a key role of neuron-astrocyte metabolic interactions. This article reviews some of the most salient features emerging from recent studies and aims at providing an integration of brain energy metabolism across resolution scales. Copyright © 2015 Elsevier Inc. All rights reserved.

Hypothalamic control of energy and glucose metabolism.

PubMed

Sisley, Stephanie; Sandoval, Darleen

2011-09-01

The central nervous system (CNS), generally accepted to regulate energy homeostasis, has been implicated in the metabolic perturbations that either cause or are associated with obesity. Normally, the CNS receives hormonal, metabolic, and neuronal input to assure adequate energy levels and maintain stable energy homeostasis. Recent evidence also supports that the CNS uses these same inputs to regulate glucose homeostasis and this aspect of CNS regulation also becomes impaired in the face of dietary-induced obesity. This review focuses on the literature surrounding hypothalamic regulation of energy and glucose homeostasis and discusses how dysregulation of this system may contribute to obesity and T2DM.

Synergy between (13)C-metabolic flux analysis and flux balance analysis for understanding metabolic adaptation to anaerobiosis in E. coli.

PubMed

Chen, Xuewen; Alonso, Ana P; Allen, Doug K; Reed, Jennifer L; Shachar-Hill, Yair

2011-01-01

Genome-based Flux Balance Analysis (FBA) and steady-state isotopic-labeling-based Metabolic Flux Analysis (MFA) are complimentary approaches to predicting and measuring the operation and regulation of metabolic networks. Here, genome-derived models of Escherichia coli (E. coli) metabolism were used for FBA and ¹³C-MFA analyses of aerobic and anaerobic growths of wild-type E. coli (K-12 MG1655) cells. Validated MFA flux maps reveal that the fraction of maintenance ATP consumption in total ATP production is about 14% higher under anaerobic (51.1%) than aerobic conditions (37.2%). FBA revealed that an increased ATP utilization is consumed by ATP synthase to secrete protons from fermentation. The TCA cycle is shown to be incomplete in aerobically growing cells and submaximal growth is due to limited oxidative phosphorylation. An FBA was successful in predicting product secretion rates in aerobic culture if both glucose and oxygen uptake measurement were constrained, but the most-frequently predicted values of internal fluxes yielded from sampling the feasible space differ substantially from MFA-derived fluxes. © 2010 Elsevier Inc. All rights reserved.

Novel Metabolic Attributes of the Genus Cyanothece, Comprising a Group of Unicellular Nitrogen-Fixing Cyanobacteria

PubMed Central

Bandyopadhyay, Anindita; Elvitigala, Thanura; Welsh, Eric; Stöckel, Jana; Liberton, Michelle; Min, Hongtao; Sherman, Louis A.; Pakrasi, Himadri B.

2011-01-01

ABSTRACT The genus Cyanothece comprises unicellular cyanobacteria that are morphologically diverse and ecologically versatile. Studies over the last decade have established members of this genus to be important components of the marine ecosystem, contributing significantly to the nitrogen and carbon cycle. System-level studies of Cyanothece sp. ATCC 51142, a prototypic member of this group, revealed many interesting metabolic attributes. To identify the metabolic traits that define this class of cyanobacteria, five additional Cyanothece strains were sequenced to completion. The presence of a large, contiguous nitrogenase gene cluster and the ability to carry out aerobic nitrogen fixation distinguish Cyanothece as a genus of unicellular, aerobic nitrogen-fixing cyanobacteria. Cyanothece cells can create an anoxic intracellular environment at night, allowing oxygen-sensitive processes to take place in these oxygenic organisms. Large carbohydrate reserves accumulate in the cells during the day, ensuring sufficient energy for the processes that require the anoxic phase of the cells. Our study indicates that this genus maintains a plastic genome, incorporating new metabolic capabilities while simultaneously retaining archaic metabolic traits, a unique combination which provides the flexibility to adapt to various ecological and environmental conditions. Rearrangement of the nitrogenase cluster in Cyanothece sp. strain 7425 and the concomitant loss of its aerobic nitrogen-fixing ability suggest that a similar mechanism might have been at play in cyanobacterial strains that eventually lost their nitrogen-fixing ability. PMID:21972240

Current technical approaches to brain energy metabolism.

PubMed

Barros, L Felipe; Bolaños, Juan P; Bonvento, Gilles; Bouzier-Sore, Anne-Karine; Brown, Angus; Hirrlinger, Johannes; Kasparov, Sergey; Kirchhoff, Frank; Murphy, Anne N; Pellerin, Luc; Robinson, Michael B; Weber, Bruno

2018-06-01

Neuroscience is a technology-driven discipline and brain energy metabolism is no exception. Once satisfied with mapping metabolic pathways at organ level, we are now looking to learn what it is exactly that metabolic enzymes and transporters do and when, where do they reside, how are they regulated, and how do they relate to the specific functions of neurons, glial cells, and their subcellular domains and organelles, in different areas of the brain. Moreover, we aim to quantify the fluxes of metabolites within and between cells. Energy metabolism is not just a necessity for proper cell function and viability but plays specific roles in higher brain functions such as memory processing and behavior, whose mechanisms need to be understood at all hierarchical levels, from isolated proteins to whole subjects, in both health and disease. To this aim, the field takes advantage of diverse disciplines including anatomy, histology, physiology, biochemistry, bioenergetics, cellular biology, molecular biology, developmental biology, neurology, and mathematical modeling. This article presents a well-referenced synopsis of the technical side of brain energy metabolism research. Detail and jargon are avoided whenever possible and emphasis is given to comparative strengths, limitations, and weaknesses, information that is often not available in regular articles. © 2017 Wiley Periodicals, Inc.

The Energy Maintenance Theory of Aging: Maintaining Energy Metabolism to Allow Longevity.

PubMed

Chaudhari, Snehal N; Kipreos, Edward T

2018-06-14

Fused, elongated mitochondria are more efficient in generating ATP than fragmented mitochondria. In diverse C. elegans longevity pathways, increased levels of fused mitochondria are associated with lifespan extension. Blocking mitochondrial fusion in these animals abolishes their extended longevity. The long-lived C. elegans vhl-1 mutant is an exception that does not have increased fused mitochondria, and is not dependent on fusion for longevity. Loss of mammalian VHL upregulates alternate energy generating pathways. This suggests that mitochondrial fusion facilitates longevity in C. elegans by increasing energy metabolism. In diverse animals, ATP levels broadly decreases with age. Substantial evidence supports the theory that increasing or maintaining energy metabolism promotes the survival of older animals. Increased ATP levels in older animals allow energy-intensive repair and homeostatic mechanisms such as proteostasis that act to prevent cellular aging. These observations support the emerging paradigm that maintaining energy metabolism promotes the survival of older animals. © 2018 WILEY Periodicals, Inc.

Exercise training improves fat metabolism independent of total energy expenditure in sedentary overweight men, but does not restore lean metabolic phenotype.

PubMed

Lefai, E; Blanc, S; Momken, I; Antoun, E; Chery, I; Zahariev, A; Gabert, L; Bergouignan, A; Simon, C

2017-12-01

Obesity is a dietary fat storage disease. Although exercise prevents weight gain, effects of chronic training on dietary fat oxidation remains understudied in overweight adults. We tested whether 2 months of training at current guidelines increase dietary fat oxidation in sedentary overweight adults like in sedentary lean adults. Sedentary lean (n=10) and overweight (n=9) men trained on a cycle ergometer at 50% VO 2peak , 1 h day -1 , four times per week, for 2 months while energy balance was clamped. Metabolic fate of [d 31 ]palmitate and [1- 13 C]oleate mixed in standard meals, total substrate use, total energy expenditure (TEE), activity energy expenditure (AEE) and key muscle proteins/enzymes were measured before and at the end of the intervention. Conversely to lean subjects, TEE and AEE did not increase in overweight participants due to a spontaneous decrease in non-training AEE. Despite this compensatory behavior, aerobic fitness, insulin sensitivity and fat oxidation were improved by exercise training. The latter was not explained by changes in dietary fat trafficking but more likely by a coordinated response at the muscle level enhancing fat uptake, acylation and oxidation (FABPpm, CD36, FATP1, ACSL1, CPT1, mtGPAT). ACSL1 fold change positively correlated with total fasting (R 2 =0.59, P<0.0001) and post-prandial (R 2 =0.49, P=0.0006) fat oxidation whereas mtGPAT fold change negatively correlated with dietary palmitate oxidation (R 2 =0.40, P=0.009), suggesting modified fat trafficking between oxidation and storage within the muscle. However, for most of the measured parameters the post-training values observed in overweight adults remained lower than the pre-training values observed in the lean subjects. Independent of energy balance and TEE, exercise training at current recommendations improved fitness and fat oxidation in overweight adults. However the improved metabolic phenotype of overweight adults was not as healthy as the one of their lean

Effectiveness of physical activity intervention among government employees with metabolic syndrome.

PubMed

Huei Phing, Chee; Abu Saad, Hazizi; Barakatun Nisak, M Y; Mohd Nasir, M T

2017-12-01

Our study aimed to assess the effects of physical activity interventions via standing banners (point-of-decision prompt) and aerobics classes to promote physical activity among individuals with metabolic syndrome. We conducted a cluster randomized controlled intervention trial (16-week intervention and 8-week follow-up). Malaysian government employees in Putrajaya, Malaysia, with metabolic syndrome were randomly assigned by cluster to a point-of-decision prompt group (n = 44), an aerobics group (n = 42) or a control group (n = 103) based on sample size calculation formula. Step counts were evaluated by Lifecorder e-STEP accelerometers for all participants. Metabolic syndrome was defined according to the 'harmonizing' definition, in which individuals who have at least three of the five metabolic risk factors (waist circumference, high-density lipoprotein cholesterol, triglycerides, fasting glucose levels, systolic and diastolic blood pressure) will be classified as having metabolic syndrome. A total of 80% of the enrolled government employees with metabolic syndrome completed the programme. Data were analyzed using SPSS for Windows (version 20, SPSS, Chicago, IL). There were significantly higher step counts on average in the aerobics group compared to the control group over assessments. Assessments at baseline, post-intervention and follow-up showed a significant difference in step counts between the intervention and control groups. The greatest reductions in the proportions of individuals with metabolic syndrome were observed in the aerobics group with a reduction of 79.4% in the post-intervention assessment compared to the assessment at baseline. The findings of this study suggest that physical activity intervention via aerobics classes is an effective strategy for improving step counts and reducing the prevalence of metabolic syndrome.

A universal molecular clock of protein folds and its power in tracing the early history of aerobic metabolism and planet oxygenation.

PubMed

Wang, Minglei; Jiang, Ying-Ying; Kim, Kyung Mo; Qu, Ge; Ji, Hong-Fang; Mittenthal, Jay E; Zhang, Hong-Yu; Caetano-Anollés, Gustavo

2011-01-01

The standard molecular clock describes a constant rate of molecular evolution and provides a powerful framework for evolutionary timescales. Here, we describe the existence and implications of a molecular clock of folds, a universal recurrence in the discovery of new structures in the world of proteins. Using a phylogenomic structural census in hundreds of proteomes, we build phylogenies and time lines of domains at fold and fold superfamily levels of structural complexity. These time lines correlate approximately linearly with geological timescales and were here used to date two crucial events in life history, planet oxygenation and organism diversification. We first dissected the structures and functions of enzymes in simulated metabolic networks. The placement of anaerobic and aerobic enzymes in the time line revealed that aerobic metabolism emerged about 2.9 billion years (giga-annum; Ga) ago and expanded during a period of about 400 My, reaching what is known as the Great Oxidation Event. During this period, enzymes recruited old and new folds for oxygen-mediated enzymatic activities. Remarkably, the first fold lost by a superkingdom disappeared in Archaea 2.6 Ga ago, within the span of oxygen rise, suggesting that oxygen also triggered diversification of life. The implications of a molecular clock of folds are many and important for the neutral theory of molecular evolution and for understanding the growth and diversity of the protein world. The clock also extends the standard concept that was specific to molecules and their timescales and turns it into a universal timescale-generating tool.

[Isolation and identification of electrochemically active microorganism from micro-aerobic environment].

PubMed

Wu, Song; Xiao, Yong; Zheng, Zhi-Yong; Zheng, Yue; Yang, Zhao-Hui; Zhao, Feng

2014-10-01

Extracellular electron transfer of electrochemically active microorganism plays vital role in biogeochemical cycling of metals and carbon and in biosynthesis of bioenergy. Compared to anaerobic anode, micro-aerobic anode captures more energy from microbial fuel cell. However, most of previous researches focused on functioning bacteria in anaerobic anode, functioning bacteria in micro-aerobic anode was rarely studied. Herein, we used the traditional aerobic screening technology to isolate functioning bacteria from a micro-aerobic anode. Three pure cultures Aeromonas sp. WS-XY2, Citrobacter sp. WS-XY3 and Bacterium strain WS-XY4 were obtained. WS-XY2 and WS-XY3 were belonged to Proteobacteria, whereas WS-XY4 was possibly a new species. Cyclic voltammetry and chronoamperometry analysis demonstrated all of them showed the electrochemical activity by direct extracellular electron transfer, and micro-aerobic anode could select bacteria that have similar electrochemical activity to proliferate on the anode. We further conclude that functioning bacteria in micro-aerobic anode are more efficient than that of anaerobic anode may be the reason that micro-aerobic anode has better performance than anaerobic anode. Therefore, a thorough study of functioning bacteria in micro-aerobic anode will significantly promote the energy recovery from microbial fuel cell.

Benefits of aerobic exercise after stroke.

PubMed

Potempa, K; Braun, L T; Tinknell, T; Popovich, J

1996-05-01

The debilitating loss of function after a stroke has both primary and secondary effects on sensorimotor function. Primary effects include paresis, paralysis, spasticity, and sensory-perceptual dysfunction due to upper motor neuron damage. Secondary effects, contractures and disuse muscle atrophy, are also debilitating. This paper presents theoretical and empirical benefits of aerobic exercise after stroke, issues relevant to measuring peak capacity, exercise training protocols, and the clinical use of aerobic exercise in this patient population. A stroke, and resulting hemiparesis, produces physiological changes in muscle fibres and muscle metabolism during exercise. These changes, along with comorbid cardiovascular disease, must be considered when exercising stroke patients. While few studies have measured peak exercise capacity in hemiparetic populations, it has been consistently observed in these studies that stroke patients have a lower functional capacity than healthy populations. Hemiparetic patients have low peak exercise responses probably due to a reduced number of motor units available for recruitment during dynamic exercise, the reduced oxidative capacity of paretic muscle, and decreased overall endurance. Consequently, traditional methods to predict aerobic capacity are not appropriate for use with stroke patients. Endurance exercise training is increasingly recognised as an important component in rehabilitation. An average improvement in maximal oxygen consumption (VO2max) of 13.3% in stroke patients who participated in a 10-week aerobic exercise training programme has been reported compared with controls. This study underscored the potential benefits of aerobic exercise training in stroke patients. In this paper, advantages and disadvantages of exercise modalities are discussed in relation to stroke patients. Recommendations are presented to maximise physical performance and minimise potential cardiac risks during exercise.

Respiration, respiratory metabolism and energy consumption under weightless conditions

NASA Technical Reports Server (NTRS)

Kasyan, I. I.; Makarov, G. F.

1975-01-01

Changes in the physiological indices of respiration, respiratory metabolism and energy consumption in spacecrews under weightlessness conditions manifest themselves in increased metabolic rates, higher pulmonary ventilation volume, oxygen consumption and carbon dioxide elimination, energy consumption levels in proportion to reduction in neuroemotional and psychic stress, adaptation to weightlessness and work-rest cycles, and finally in a relative stabilization of metabolic processes due to hemodynamic shifts.

Natural light-micro aerobic condition for PSB wastewater treatment: a flexible, simple, and effective resource recovery wastewater treatment process.

PubMed

Lu, Haifeng; Han, Ting; Zhang, Guangming; Ma, Shanshan; Zhang, Yuanhui; Li, Baoming; Cao, Wei

2018-01-01

Photosynthetic bacteria (PSB) have two sets of metabolic pathways. They can degrade pollutants through light metabolic under light-anaerobic or oxygen metabolic pathways under dark-aerobic conditions. Both metabolisms function under natural light-microaerobic condition, which demands less energy input. This work investigated the characteristics of PSB wastewater treatment process under that condition. Results showed that PSB had very strong adaptability to chemical oxygen demand (COD) concentration; with F/M of 5.2-248.5 mg-COD/mg-biomass, the biomass increased three times and COD removal reached above 91.5%. PSB had both advantages of oxygen metabolism in COD removal and light metabolism in resource recovery under natural light-microaerobic condition. For pollutants' degradation, COD, total organic carbon, nitrogen, and phosphorus removal reached 96.2%, 91.0%, 70.5%, and 92.7%, respectively. For resource recovery, 74.2% of C in wastewater was transformed into biomass. Especially, coexistence of light and oxygen promote N recovery ratio to 70.9%, higher than with the other two conditions. Further, 93.7% of N-removed was synthesized into biomass. Finally, CO 2 emission reduced by 62.6% compared with the traditional process. PSB wastewater treatment under this condition is energy-saving, highly effective, and environment friendly, and can achieve pollution control and resource recovery.

Effects of Furfural on the Respiratory Metabolism of Saccharomyces cerevisiae in Glucose-Limited Chemostats

PubMed Central

Sárvári Horváth, Ilona; Franzén, Carl Johan; Taherzadeh, Mohammad J.; Niklasson, Claes; Lidén, Gunnar

2003-01-01

Effects of furfural on the aerobic metabolism of the yeast Saccharomyces cerevisiae were studied by performing chemostat experiments, and the kinetics of furfural conversion was analyzed by performing dynamic experiments. Furfural, an important inhibitor present in lignocellulosic hydrolysates, was shown to have an inhibitory effect on yeast cells growing respiratively which was much greater than the inhibitory effect previously observed for anaerobically growing yeast cells. The residual furfural concentration in the bioreactor was close to zero at all steady states obtained, and it was found that furfural was exclusively converted to furoic acid during respiratory growth. A metabolic flux analysis showed that furfural affected fluxes involved in energy metabolism. There was a 50% increase in the specific respiratory activity at the highest steady-state furfural conversion rate. Higher furfural conversion rates, obtained during pulse additions of furfural, resulted in respirofermentative metabolism, a decrease in the biomass yield, and formation of furfuryl alcohol in addition to furoic acid. Under anaerobic conditions, reduction of furfural partially replaced glycerol formation as a way to regenerate NAD+. At concentrations above the inlet concentration of furfural, which resulted in complete replacement of glycerol formation by furfuryl alcohol production, washout occurred. Similarly, when the maximum rate of oxidative conversion of furfural to furoic acid was exceeded aerobically, washout occurred. Thus, during both aerobic growth and anaerobic growth, the ability to tolerate furfural appears to be directly coupled to the ability to convert furfural to less inhibitory compounds. PMID:12839784

The cross-tissue metabolic response of abalone (Haliotis midae) to functional hypoxia.

PubMed

Venter, Leonie; Loots, Du Toit; Mienie, Lodewyk J; Jansen van Rensburg, Peet J; Mason, Shayne; Vosloo, Andre; Lindeque, Jeremie Z

2018-03-23

Functional hypoxia is a stress condition caused by the abalone itself as a result of increased muscle activity, which generally necessitates the employment of anaerobic metabolism if the activity is sustained for prolonged periods. With that being said, abalone are highly reliant on anaerobic metabolism to provide partial compensation for energy production during oxygen-deprived episodes. However, current knowledge on the holistic metabolic response for energy metabolism during functional hypoxia, and the contribution of different metabolic pathways and various abalone tissues towards the overall accumulation of anaerobic end-products in abalone are scarce. Metabolomics analysis of adductor muscle, foot muscle, left gill, right gill, haemolymph and epipodial tissue samples indicated that South African abalone ( Haliotis midae) subjected to functional hypoxia utilises predominantly anaerobic metabolism, and depends on all of the main metabolite classes (proteins, carbohydrates and lipids) for energy supply. Functional hypoxia caused increased levels of anaerobic end-products: lactate, alanopine, tauropine, succinate and alanine. Also, elevation in arginine levels was detected, confirming that abalone use phosphoarginine to generate energy during functional hypoxia. Different tissues showed varied metabolic responses to hypoxia, with functional hypoxia showing excessive changes in the adductor muscle and gills. From this metabolomics investigation, it becomes evident that abalone are metabolically able to produce sufficient amounts of energy when functional hypoxia is experienced. Also, tissue interplay enables the adjustment of H. midae energy requirements as their metabolism shifts from aerobic to anaerobic respiration during functional hypoxia.This article has an associated First Person interview with the first author of the paper. © 2018. Published by The Company of Biologists Ltd.

The cross-tissue metabolic response of abalone (Haliotis midae) to functional hypoxia

PubMed Central

Venter, Leonie; Loots, Du Toit; Mienie, Lodewyk J.; Jansen van Rensburg, Peet J.; Mason, Shayne; Vosloo, Andre

2018-01-01

ABSTRACT Functional hypoxia is a stress condition caused by the abalone itself as a result of increased muscle activity, which generally necessitates the employment of anaerobic metabolism if the activity is sustained for prolonged periods. With that being said, abalone are highly reliant on anaerobic metabolism to provide partial compensation for energy production during oxygen-deprived episodes. However, current knowledge on the holistic metabolic response for energy metabolism during functional hypoxia, and the contribution of different metabolic pathways and various abalone tissues towards the overall accumulation of anaerobic end-products in abalone are scarce. Metabolomics analysis of adductor muscle, foot muscle, left gill, right gill, haemolymph and epipodial tissue samples indicated that South African abalone (Haliotis midae) subjected to functional hypoxia utilises predominantly anaerobic metabolism, and depends on all of the main metabolite classes (proteins, carbohydrates and lipids) for energy supply. Functional hypoxia caused increased levels of anaerobic end-products: lactate, alanopine, tauropine, succinate and alanine. Also, elevation in arginine levels was detected, confirming that abalone use phosphoarginine to generate energy during functional hypoxia. Different tissues showed varied metabolic responses to hypoxia, with functional hypoxia showing excessive changes in the adductor muscle and gills. From this metabolomics investigation, it becomes evident that abalone are metabolically able to produce sufficient amounts of energy when functional hypoxia is experienced. Also, tissue interplay enables the adjustment of H. midae energy requirements as their metabolism shifts from aerobic to anaerobic respiration during functional hypoxia. This article has an associated First Person interview with the first author of the paper. PMID:29572259

Energy metabolism in human obesity.

PubMed

Jéquier, E

1989-01-01

Obesity results from a chronic imbalance between energy intake and expenditure. Accurate measurements of total energy expenditure of lean and obese individuals with a respiration chamber have clearly shown that obese individuals expand more energy than lean sedentary subjects. Studies on the body composition of obese individuals reveal that not only the fat mass is enlarged, but the fat-free mass is also increased as compared with that of lean subjects. Since basal metabolic rate is proportional to the fat-free mass, obese subjects have a greater basal metabolic rate than lean controls. The energy cost of weight bearing activities such as walking and standing is related to body weight, and is therefore increased in obese individuals. The thermogenic response to food ingestion, the diet-induced thermogenesis, has been found to be reduced in some groups of obese people, but not in all obese individuals. The thermic effect of glucose or to meal ingestion is blunted in obese subjects with insulin resistance. Any alteration in thermogenic responses to a caloric excess can be important to store or to oxidize part of the excessive energy intake. After weight reduction in obese subjects due to a hypocaloric diet, the total 24-hour energy expenditure decreases by 20 to 25 kcal/day for each kilogram of weight loss. Failure to adapt the every day energy intake accordingly will result in body weight gain and relapse of obesity.

Extensive Functional Evaluations to Monitor Aerobic Training in Becker Muscular Dystrophy: A Case Report.

PubMed

Tramonti, Caterina; Rossi, Bruno; Chisari, Carmelo

2016-06-13

Low-intensity aerobic training seems to have positive effects on muscle strength, endurance and fatigue in Becker Muscular Dystrophy (BMD) patients. We describe the case of a 33-year old BMD man, who performed a four-week aerobic training. Extensive functional evaluations were executed to monitor the efficacy of the rehabilitative treatment. Results evidenced an increased force exertion and an improvement in muscle contraction during sustained exercise. An improvement of walk velocity, together with agility, endurance capacity and oxygen consumption during exercise was observed. Moreover, an enhanced metabolic efficiency was evidenced, as shown by reduced lactate blood levels after training. Interestingly, CK showed higher levels after the training protocol, revealing possible muscle damage. In conclusion, aerobic training may represent an effective method improving exercise performance, functional status and metabolic efficiency. Anyway, a careful functional assessment should be taken into account as a useful approach in the management of the disease's rehabilitative treatment.

Aspects of astrocyte energy metabolism, amino acid neurotransmitter homoeostasis and metabolic compartmentation

PubMed Central

Kreft, Marko; Bak, Lasse K; Waagepetersen, Helle S; Schousboe, Arne

2012-01-01

Astrocytes are key players in brain function; they are intimately involved in neuronal signalling processes and their metabolism is tightly coupled to that of neurons. In the present review, we will be concerned with a discussion of aspects of astrocyte metabolism, including energy-generating pathways and amino acid homoeostasis. A discussion of the impact that uptake of neurotransmitter glutamate may have on these pathways is included along with a section on metabolic compartmentation. PMID:22435484

Down-regulated energy metabolism genes associated with mitochondria oxidative phosphorylation and fatty acid metabolism in viral cardiomyopathy mouse heart.

PubMed

Xu, Jing; Nie, Hong-gang; Zhang, Xiao-dong; Tian, Ye; Yu, Bo

2011-08-01

The majority of experimental and clinical studies indicates that the hypertrophied and failing myocardium are characterized by changes in energy and substrate metabolism that attributed to failing heart changes at the genomic level, in fact, heart failure is caused by various diseases, their energy metabolism and substrate are in different genetic variations, then the potential significance of the molecular mechanisms for the aetiology of heart failure is necessary to be evaluated. Persistent viral infection (especially coxsackievirus group B3) of the myocardium in viral myocarditis and viral dilated cardiomyopathy has never been neglected by experts. This study aimed to explore the role and regulatory mechanism of the altered gene expression for energy metabolism involved in mitochondrial oxidative phosphorylation, fatty acid metabolism in viral dilated cardiomyopathy. cDNA Microarray technology was used to evaluate the expression of >35,852 genes in a mice model of viral dilated cardiomyopathy. In total 1385 highly different genes expression, we analyzed 33 altered genes expression for energy metabolism involved in mitochondrial oxidative phosphorylation, fatty acid metabolism and further selected real-time-PCR for quantity one of regulatory mechanisms for energy including fatty acid metabolism-the UCP2 and assayed cytochrome C oxidase activity by Spectrophotometer to explore mitochondrial oxidative phosphorylation function. We found obviously different expression of 33 energy metabolism genes associated with mitochondria oxidative phosphorylation, fatty acid metabolism in cardiomyopathy mouse heart, the regulatory gene for energy metabolism: UCP2 was down-regulated and cytochrome C oxidase activity was decreased. Genes involved in both fatty acid metabolism and mitochondrial oxidative phosphorylation were down-regulated, mitochondrial uncoupling proteins (UCP2) expression did not increase but decrease which might be a kind of adaptive protection response to

Maximal aerobic and anaerobic power generation in large crocodiles versus mammals: implications for dinosaur gigantothermy.

PubMed

Seymour, Roger S

2013-01-01

Inertial homeothermy, the maintenance of a relatively constant body temperature that occurs simply because of large size, is often applied to large dinosaurs. Moreover, biophysical modelling and actual measurements show that large crocodiles can behaviourally achieve body temperatures above 30°C. Therefore it is possible that some dinosaurs could achieve high and stable body temperatures without the high energy cost of typical endotherms. However it is not known whether an ectothermic dinosaur could produce the equivalent amount of muscular power as an endothermic one. To address this question, this study analyses maximal power output from measured aerobic and anaerobic metabolism in burst exercising estuarine crocodiles, Crocodylusporosus, weighing up to 200 kg. These results are compared with similar data from endothermic mammals. A 1 kg crocodile at 30°C produces about 16 watts from aerobic and anaerobic energy sources during the first 10% of exhaustive activity, which is 57% of that expected for a similarly sized mammal. A 200 kg crocodile produces about 400 watts, or only 14% of that for a mammal. Phosphocreatine is a minor energy source, used only in the first seconds of exercise and of similar concentrations in reptiles and mammals. Ectothermic crocodiles lack not only the absolute power for exercise, but also the endurance, that are evident in endothermic mammals. Despite the ability to achieve high and fairly constant body temperatures, therefore, large, ectothermic, crocodile-like dinosaurs would have been competitively inferior to endothermic, mammal-like dinosaurs with high aerobic power. Endothermy in dinosaurs is likely to explain their dominance over mammals in terrestrial ecosystems throughout the Mesozoic.

Maximal Aerobic and Anaerobic Power Generation in Large Crocodiles versus Mammals: Implications for Dinosaur Gigantothermy

PubMed Central

Seymour, Roger S.

2013-01-01

Inertial homeothermy, the maintenance of a relatively constant body temperature that occurs simply because of large size, is often applied to large dinosaurs. Moreover, biophysical modelling and actual measurements show that large crocodiles can behaviourally achieve body temperatures above 30°C. Therefore it is possible that some dinosaurs could achieve high and stable body temperatures without the high energy cost of typical endotherms. However it is not known whether an ectothermic dinosaur could produce the equivalent amount of muscular power as an endothermic one. To address this question, this study analyses maximal power output from measured aerobic and anaerobic metabolism in burst exercising estuarine crocodiles, Crocodylusporosus , weighing up to 200 kg. These results are compared with similar data from endothermic mammals. A 1 kg crocodile at 30°C produces about 16 watts from aerobic and anaerobic energy sources during the first 10% of exhaustive activity, which is 57% of that expected for a similarly sized mammal. A 200 kg crocodile produces about 400 watts, or only 14% of that for a mammal. Phosphocreatine is a minor energy source, used only in the first seconds of exercise and of similar concentrations in reptiles and mammals. Ectothermic crocodiles lack not only the absolute power for exercise, but also the endurance, that are evident in endothermic mammals. Despite the ability to achieve high and fairly constant body temperatures, therefore, large, ectothermic, crocodile-like dinosaurs would have been competitively inferior to endothermic, mammal-like dinosaurs with high aerobic power. Endothermy in dinosaurs is likely to explain their dominance over mammals in terrestrial ecosystems throughout the Mesozoic. PMID:23861968

Promiscuous anaerobes: new and unconventional metabolism in methanogenic archaea.

PubMed

Grochowski, Laura L; White, Robert H

2008-03-01

The development of an oxygenated atmosphere on earth resulted in the polarization of life into two major groups, those that could live in the presence of oxygen and those that could not-the aerobes and the anaerobes. The evolution of aerobes from the earliest anaerobic prokaryotes resulted in a variety of metabolic adaptations. Many of these adaptations center on the need to sustain oxygen-sensitive reactions and cofactors to function in the new oxygen-containing atmosphere. Still other metabolic pathways that were not sensitive to oxygen also diverged. This is likely due to the physical separation of the organisms, based on their ability to live in the presence of oxygen, which allowed for the independent evolution of the pathways. Through the study of metabolic pathways in anaerobes and comparison to the more established pathways from aerobes, insight into metabolic evolution can be gained. This, in turn, can allow for extra- polation to those metabolic pathways occurring in the Last Universal Common Ancestor (LUCA). Some of the unique and uncanonical metabolic pathways that have been identified in the archaea with emphasis on the biochemistry of an obligate anaerobic methanogen, Methanocaldococcus jannaschii are reviewed.

Inhibiting aerobic glycolysis suppresses renal interstitial fibroblast activation and renal fibrosis.

PubMed

Ding, Hao; Jiang, Lei; Xu, Jing; Bai, Feng; Zhou, Yang; Yuan, Qi; Luo, Jing; Zen, Ke; Yang, Junwei

2017-09-01

Chronic kidney diseases generally lead to renal fibrosis. Despite great progress having been made in identifying molecular mediators of fibrosis, the mechanism that governs renal fibrosis remains unclear, and so far no effective therapeutic antifibrosis strategy is available. Here we demonstrated that a switch of metabolism from oxidative phosphorylation to aerobic glycolysis (Warburg effect) in renal fibroblasts was the primary feature of fibroblast activation during renal fibrosis and that suppressing renal fibroblast aerobic glycolysis could significantly reduce renal fibrosis. Both gene and protein assay showed that the expression of glycolysis enzymes was upregulated in mouse kidneys with unilateral ureter obstruction (UUO) surgery or in transforming growth factor-β1 (TGF-β1)-treated renal interstitial fibroblasts. Aerobic glycolysis flux, indicated by glucose uptake and lactate production, was increased in mouse kidney with UUO nephropathy or TGF-β1-treated renal interstitial fibroblasts and positively correlated with fibrosis process. In line with this, we found that increasing aerobic glycolysis can remarkably induce myofibroblast activation while aerobic glycolysis inhibitors shikonin and 2-deoxyglucose attenuate UUO-induced mouse renal fibrosis and TGF-β1-stimulated myofibroblast activation. Furthermore, mechanistic study indicated that shikonin inhibits renal aerobic glycolysis via reducing phosphorylation of pyruvate kinase type M2, a rate-limiting glycolytic enzyme associated with cell reliance on aerobic glycolysis. In conclusion, our findings demonstrate the critical role of aerobic glycolysis in renal fibrosis and support treatment with aerobic glycolysis inhibitors as a potential antifibrotic strategy. Copyright © 2017 the American Physiological Society.

The metabolic syndrome and the immediate antihypertensive effects of aerobic exercise: a randomized control design.

PubMed

Pescatello, Linda S; Blanchard, Bruce E; Van Heest, Jaci L; Maresh, Carl M; Gordish-Dressman, Heather; Thompson, Paul D

2008-06-10

The metabolic syndrome (Msyn) affects about 40% of those with hypertension. The Msyn and hypertension have a common pathophysiology. Exercise is recommended for their treatment, prevention and control. The influence of the Msyn on the antihypertensive effects of aerobic exercise is not known. We examined the influence of the Msyn on the blood pressure (BP) response following low (LIGHT, 40% peak oxygen consumption, VO2peak) and moderate (MODERATE, 60% VO2peak) intensity, aerobic exercise. Subjects were 46 men (44.3 +/- 1.3 yr) with pre- to Stage 1 hypertension (145.5 +/- 1.6/86.3 +/- 1.2 mmHg) and borderline dyslipidemia. Men with Msyn (n = 18) had higher fasting insulin, triglycerides and homeostasis model assessment (HOMA) and lower high density lipoprotein than men without Msyn (n = 28) (p < 0.01). Subjects consumed a standard meal and 2 hr later completed one of three randomized experiments separated by 48 hr. The experiments were a non-exercise control session of seated rest and two cycle bouts (LIGHT and MODERATE). BP, insulin and glucose were measured before, during and after the 40 min experiments. Subjects left the laboratory wearing an ambulatory BP monitor for the remainder of the day. Repeated measure ANCOVA tested if BP, insulin and glucose differed over time among experiments in men without and with the Msyn with HOMA as a covariate. Multivariable regression analyses examined associations among BP, insulin, glucose and the Msyn. Systolic BP (SBP) was reduced 8 mmHg (p < 0.05) and diastolic BP (DBP) 5 mmHg (p = 0.052) after LIGHT compared to non-exercise control over 9 hr among men without versus with Msyn. BP was not different after MODERATE versus non-exercise control between Msyn groups (p > or = 0.05). The factors accounting for 17% of the SBP response after LIGHT were baseline SBP (beta = -0.351, r2 = 0.123, p = 0.020), Msyn (beta = 0.277, r2 = 0.077, p = 0.069), and HOMA (beta = -0.124, r2 = 0.015, p = 0.424). Msyn (r2 = 0.096, p = 0.036) was the

Novel metabolic attributes of the genus cyanothece, comprising a group of unicellular nitrogen-fixing Cyanothece.

PubMed

Bandyopadhyay, Anindita; Elvitigala, Thanura; Welsh, Eric; Stöckel, Jana; Liberton, Michelle; Min, Hongtao; Sherman, Louis A; Pakrasi, Himadri B

2011-01-01

The genus Cyanothece comprises unicellular cyanobacteria that are morphologically diverse and ecologically versatile. Studies over the last decade have established members of this genus to be important components of the marine ecosystem, contributing significantly to the nitrogen and carbon cycle. System-level studies of Cyanothece sp. ATCC 51142, a prototypic member of this group, revealed many interesting metabolic attributes. To identify the metabolic traits that define this class of cyanobacteria, five additional Cyanothece strains were sequenced to completion. The presence of a large, contiguous nitrogenase gene cluster and the ability to carry out aerobic nitrogen fixation distinguish Cyanothece as a genus of unicellular, aerobic nitrogen-fixing cyanobacteria. Cyanothece cells can create an anoxic intracellular environment at night, allowing oxygen-sensitive processes to take place in these oxygenic organisms. Large carbohydrate reserves accumulate in the cells during the day, ensuring sufficient energy for the processes that require the anoxic phase of the cells. Our study indicates that this genus maintains a plastic genome, incorporating new metabolic capabilities while simultaneously retaining archaic metabolic traits, a unique combination which provides the flexibility to adapt to various ecological and environmental conditions. Rearrangement of the nitrogenase cluster in Cyanothece sp. strain 7425 and the concomitant loss of its aerobic nitrogen-fixing ability suggest that a similar mechanism might have been at play in cyanobacterial strains that eventually lost their nitrogen-fixing ability. The unicellular cyanobacterial genus Cyanothece has significant roles in the nitrogen cycle in aquatic and terrestrial environments. Cyanothece sp. ATCC 51142 was extensively studied over the last decade and has emerged as an important model photosynthetic microbe for bioenergy production. To expand our understanding of the distinctive metabolic capabilities of

Temperature, metabolic power and the evolution of endothermy.

PubMed

Clarke, Andrew; Pörtner, Hans-Otto

2010-11-01

Endothermy has evolved at least twice, in the precursors to modern mammals and birds. The most widely accepted explanation for the evolution of endothermy has been selection for enhanced aerobic capacity. We review this hypothesis in the light of advances in our understanding of ATP generation by mitochondria and muscle performance. Together with the development of isotope-based techniques for the measurement of metabolic rate in free-ranging vertebrates these have confirmed the importance of aerobic scope in the evolution of endothermy: absolute aerobic scope, ATP generation by mitochondria and muscle power output are all strongly temperature-dependent, indicating that there would have been significant improvement in whole-organism locomotor ability with a warmer body. New data on mitochondrial ATP generation and proton leak suggest that the thermal physiology of mitochondria may differ between organisms of contrasting ecology and thermal flexibility. Together with recent biophysical modelling, this strengthens the long-held view that endothermy originated in smaller, active eurythermal ectotherms living in a cool but variable thermal environment. We propose that rather than being a secondary consequence of the evolution of an enhanced aerobic scope, a warmer body was the means by which that enhanced aerobic scope was achieved. This modified hypothesis requires that the rise in metabolic rate and the insulation necessary to retain metabolic heat arose early in the lineages leading to birds and mammals. Large dinosaurs were warm, but were not endotherms, and the metabolic status of pterosaurs remains unresolved. © 2010 The Authors. Biological Reviews © 2010 Cambridge Philosophical Society.

Interval training based on ventilatory anaerobic threshold improves aerobic functional capacity and metabolic profile: a randomized controlled trial in coronary artery disease patients.

PubMed

Tamburús, Nayara Y; Kunz, Vandeni C; Salviati, Mariana R; Castello Simões, Viviane; Catai, Aparecida M; Da Silva, Ester

2016-02-01

Exercise training has been an essential component of cardiac rehabilitation. However, it is not known if interval training (IT) based on the ventilatory anaerobic threshold (VAT) could be effective in improving aerobic functional capacity and metabolic profile in patients without or with coronary artery disease (CAD). To investigate the effects of an IT program, based-intensity between 70-110% of workload reached at the VAT, on the aerobic functional capacity and metabolic profile of patients with and without CAD. Randomized controlled trial. Outpatients from a cardiac rehabilitation. A sample was composed of 32 patients with CAD (CAD group) and 32 patients without CAD (noCAD group) that were randomized into a trained or control groups. Submaximal cardiopulmonary exercise test on the cycle ergometer and blood samples were realized at baseline and post 16 weeks of IT program. The cardiorespiratory variables were obtained at the VAT level. Trained groups (CAD-T, N.=15; noCAD-T, N.=15) underwent a supervised three-week session IT program (30-40 minutes each exercise session, at the intensity workloads equivalent to %VAT [70-110%]) for 16 weeks. After 16 weeks of IT program, there were a significant increase of VO(2VAT) and workload in the trained groups (P<0.05), while in the control groups VO(2VAT) and heart rate decreased (P<0.05). Body mass and body index mass decreased in trained groups (P<0.05), and low-density lipoprotein increased only in noCAD group after 16 weeks (P<0.05). The magnitude of the improvement in VO(2VAT) was related to VO(2VAT) (r=-0.57, P<0.05) and workload (r=-0.52, P<0.05) at baseline. The IT program prescribed with intensities based on VAT improved the aerobic functional capacity and decreased body mass and body index mass loss in patients with and without CAD. IT program based on VAT provides new possibilities for cardiac rehabilitation in relation to individualized exercise prescription of the interval training.

CKM Gene G (Ncoi-) Allele Has a Positive Effect on Maximal Oxygen Uptake in Caucasian Women Practicing Sports Requiring Aerobic and Anaerobic Exercise Metabolism

PubMed Central

Gronek, Piotr; Holdys, Joanna; Kryściak, Jakub; Stanisławski, Daniel

2013-01-01

The search for genes with a positive influence on physical fitness is a difficult process. Physical fitness is a trait determined by multiple genes, and its genetic basis is then modified by numerous environmental factors. The present study examines the effects of the polymorphism of creatine kinase (CKM) gene on VO2max – a physiological index of aerobic capacity of high heritability. The study sample consisted of 154 men and 85 women, who were students of the University School of Physical Education in Poznań and athletes practicing various sports, including members of the Polish national team. The study revealed a positive effect of a rare G (NcoI−) allele of the CKM gene on maximal oxygen uptake in Caucasian women practicing sports requiring aerobic and anaerobic exercise metabolism. Also a tendency was noted in individuals with NcoI−/− (GG) and NcoI−/+ (GA) genotypes to reach higher VO2max levels. PMID:24511349

Identification of serum analytes and metabolites associated with aerobic capacity

USDA-ARS?s Scientific Manuscript database

Studies aimed at identifying serum markers of cellular metabolism (biomarkers) that are associated at baseline with aerobic capacity (V02 max) in young, healthy individuals have yet to be reported. Therefore, the goal of the present study was to use the standard chemistry screen and untargeted mass ...

Unraveling Interfaces between Energy Metabolism and Cell Cycle in Plants.

PubMed

Siqueira, João Antonio; Hardoim, Pablo; Ferreira, Paulo C G; Nunes-Nesi, Adriano; Hemerly, Adriana S

2018-06-19

Oscillation in energy levels is widely variable in dividing and differentiated cells. To synchronize cell proliferation and energy fluctuations, cell cycle-related proteins have been implicated in the regulation of mitochondrial energy-generating pathways in yeasts and animals. Plants have chloroplasts and mitochondria, coordinating the cell energy flow. Recent findings suggest an integrated regulation of these organelles and the nuclear cell cycle. Furthermore, reports indicate a set of interactions between the cell cycle and energy metabolism, coordinating the turnover of proteins in plants. Here, we discuss how cell cycle-related proteins directly interact with energy metabolism-related proteins to modulate energy homeostasis and cell cycle progression. We provide interfaces between cell cycle and energy metabolism-related proteins that could be explored to maximize plant yield. Copyright © 2018 Elsevier Ltd. All rights reserved.

Dissecting Leishmania infantum Energy Metabolism - A Systems Perspective

PubMed Central

Subramanian, Abhishek; Jhawar, Jitesh; Sarkar, Ram Rup

2015-01-01

Leishmania infantum, causative agent of visceral leishmaniasis in humans, illustrates a complex lifecycle pertaining to two extreme environments, namely, the gut of the sandfly vector and human macrophages. Leishmania is capable of dynamically adapting and tactically switching between these critically hostile situations. The possible metabolic routes ventured by the parasite to achieve this exceptional adaptation to its varying environments are still poorly understood. In this study, we present an extensively reconstructed energy metabolism network of Leishmania infantum as an attempt to identify certain strategic metabolic routes preferred by the parasite to optimize its survival in such dynamic environments. The reconstructed network consists of 142 genes encoding for enzymes performing 237 reactions distributed across five distinct model compartments. We annotated the subcellular locations of different enzymes and their reactions on the basis of strong literature evidence and sequence-based detection of cellular localization signal within a protein sequence. To explore the diverse features of parasite metabolism the metabolic network was implemented and analyzed as a constraint-based model. Using a systems-based approach, we also put forth an extensive set of lethal reaction knockouts; some of which were validated using published data on Leishmania species. Performing a robustness analysis, the model was rigorously validated and tested for the secretion of overflow metabolites specific to Leishmania under varying extracellular oxygen uptake rate. Further, the fate of important non-essential amino acids in L. infantum metabolism was investigated. Stage-specific scenarios of L. infantum energy metabolism were incorporated in the model and key metabolic differences were outlined. Analysis of the model revealed the essentiality of glucose uptake, succinate fermentation, glutamate biosynthesis and an active TCA cycle as driving forces for parasite energy metabolism

The role of Klotho in energy metabolism

PubMed Central

Razzaque, M. Shawkat

2013-01-01

A disproportionate expansion of white adipose tissue and abnormal recruitment of adipogenic precursor cells can not only lead to obesity but also impair glucose metabolism, which are both common causes of insulin resistance and diabetes mellitus. The development of novel and effective therapeutic strategies to slow the progression of obesity, diabetes mellitus and their associated complications will require improved understanding of adipogenesis and glucose metabolism. Klotho might have a role in adipocyte maturation and systemic glucose metabolism. Klotho increases adipocyte differentiation in vitro, and mice that lack Klotho activity are lean owing to reduced white adipose tissue accumulation; moreover, mice that lack the Kl gene (which encodes Klotho) are resistant to obesity induced by a high-fat diet. Knockout of Kl in leptin-deficient Lepob/ob mice reduces obesity and increases insulin sensitivity, which lowers blood glucose levels. Energy metabolism might also be influenced by Klotho. However, further studies are needed to explore the possibility that Klotho could be a novel therapeutic target to reduce obesity and related complications, and to determine whether and how Klotho might influence the regulation and function of a related protein, β-Klotho, which is also involved in energy metabolism. PMID:22641000

Metabolic costs of capital energy storage in a small-bodied ectotherm.

PubMed

Griffen, Blaine D

2017-04-01

Reproduction is energetically financed using strategies that fall along a continuum from animals that rely on stored energy acquired prior to reproduction (i.e., capital breeders) to those that rely on energy acquired during reproduction (i.e., income breeders). Energy storage incurs a metabolic cost. However, previous studies suggest that this cost may be minimal for small-bodied ectotherms. Here I test this assumption. I use a laboratory feeding experiment with the European green crab Carcinus maenas to establish individuals with different amounts of energy storage. I then demonstrate that differences in energy storage account for 26% of the variation in basal metabolic costs. The magnitudes of these costs for any individual crab vary through time depending on the amount of energy it has stored, as well as on temperature-dependent metabolism. I use previously established relationships between temperature- and mass-dependent metabolic rates, combined with a feasible annual pattern of energy storage in the Gulf of Maine and annual sea surface temperature patterns in this region, to estimate potential annual metabolic costs expected for mature female green crabs. Results indicate that energy storage should incur an ~8% increase in metabolic costs for female crabs, relative to a hypothetical crab that did not store any energy. Translated into feeding, for a medium-sized mature female (45 mm carapace width), this requires the consumption of an additional ~156 mussels annually to support the metabolic cost of energy storage. These results indicate, contrary to previous assumptions, that the cost of energy storage for small-bodied ectotherms may represent a considerable portion of their basic operating energy budget. An inability to meet these additional costs of energy storage may help explain the recent decline of green crabs in the Gulf of Maine where reduced prey availability and increased consumer competition have combined to hamper green crab foraging success in

Elevated temperature and PCO2 shift metabolic pathways in differentially oxidative tissues of Notothenia rossii.

PubMed

Strobel, Anneli; Leo, Elettra; Pörtner, Hans O; Mark, Felix C

2013-09-01

Mitochondrial plasticity plays a central role in setting the capacity for acclimation of aerobic metabolism in ectotherms in response to environmental changes. We still lack a clear picture if and to what extent the energy metabolism and mitochondrial enzymes of Antarctic fish can compensate for changing temperatures or PCO2 and whether capacities for compensation differ between tissues. We therefore measured activities of key mitochondrial enzymes (citrate synthase (CS), cytochrome c oxidase (COX)) from heart, red muscle, white muscle and liver in the Antarctic fish Notothenia rossii after warm- (7°C) and hypercapnia- (0.2kPa CO2) acclimation vs. control conditions (1°C, 0.04kPa CO2). In heart, enzymes showed elevated activities after cold-hypercapnia acclimation, and a warm-acclimation-induced upward shift in thermal optima. The strongest increase in enzyme activities in response to hypercapnia occurred in red muscle. In white muscle, enzyme activities were temperature-compensated. CS activity in liver decreased after warm-normocapnia acclimation (temperature-compensation), while COX activities were lower after cold- and warm-hypercapnia exposure, but increased after warm-normocapnia acclimation. In conclusion, warm-acclimated N. rossii display low thermal compensation in response to rising energy demand in highly aerobic tissues, such as heart and red muscle. Chronic environmental hypercapnia elicits increased enzyme activities in these tissues, possibly to compensate for an elevated energy demand for acid-base regulation or a compromised mitochondrial metabolism, that is predicted to occur in response to hypercapnia exposure. This might be supported by enhanced metabolisation of liver energy stores. These patterns reflect a limited capacity of N. rossii to reorganise energy metabolism in response to rising temperature and PCO2. © 2013.

Estimation of energy and nutritional intake of young men practicing aerobic sports.

PubMed

Wierniuk, Alicja; Włodarek, Dariusz

2013-01-01

Keeping to a balanced diet plays a key role in maximizing the body's efficiency so that sports training becomes more effective. Previous studies have shown that an athletes' diet is often not properly balanced, and can thus negatively affect sporting performance. To assess the energy and nutrient intake in young men practicing aerobic sport and compare them with those recommended. Subjects were 25 male athletes, aged 19-25 years, practicing aerobic sports who were students at two Warsaw Universities; The Military University of Technology and University of Physical Education. The average body mass was 80.6 +/- 9.6 kg and average height was 187.0 +/- 7.6 cm, (BMI thus being 23.01 +/- 1.70 kg/m2). Dietary assessment was based on three-day dietary recalls consisting of two weekdays and one day of the weekend. The energy and macro/ micro-nutrient intake were evaluated using the Polish Software 'Energia' package and compared to recommendations and standards. Supplements were absent from the athletes' diets. The energy value of diets were too low in most instances; average %-age deficiency was 30.22 +/- 13.76%. Total protein intake, (mean 1.41 +/- 0.36 g per kg body weight) was inadequate in 40% of cases, whilst all showed appropriate intakes of animal protein. Most subjects' carbohydrate intake (84%) was deficient; median 3.28 g/kg body weight. Fibre intake, (median 17.17 g) was also insufficient in 76% cases. Total fat intake, (33.9% +/- 5.7 energy) was too high in 32% of cases. The %-age dietary energy obtained from saturated fatty acids was 12.18% +/- 2.53 and 5.72% +/- 1.43 from polyunsaturated fatty acids, where most subjects' diet (64%) was, as well, high in cholesterol. Furthermore, significant deficiencies were observed in the following: Vitamin A (44% of group below EAR), vitamin C (80% below EAR), vitamin D (92% below EAR), foliate (84% below EAR), calcium (52% below EAR) and magnesium (60% below EAR). Vitamin E intake was however higher than the AI level

Effects of short-term step aerobics exercise on bone metabolism and functional fitness in postmenopausal women with low bone mass.

PubMed

Wen, H J; Huang, T H; Li, T L; Chong, P N; Ang, B S

2017-02-01

Measurement of bone turnover markers is an alternative way to determine the effects of exercise on bone health. A 10-week group-based step aerobics exercise significantly improved functional fitness in postmenopausal women with low bone mass, and showed a positive trend in reducing resorption activity via bone turnover markers. The major goal of this study was to determine the effects of short-term group-based step aerobics (GBSA) exercise on the bone metabolism, bone mineral density (BMD), and functional fitness of postmenopausal women (PMW) with low bone mass. Forty-eight PMW (aged 58.2 ± 3.5 years) with low bone mass (lumbar spine BMD T-score of -2.00 ± 0.67) were recruited and randomly assigned to an exercise group (EG) or to a control group (CG). Participants from the EG attended a progressive 10-week GBSA exercise at an intensity of 75-85 % of heart rate reserve, 90 min per session, and three sessions per week. Serum bone metabolic markers (C-terminal telopeptide of type 1 collagen [CTX] and osteocalcin), BMD, and functional fitness components were measured before and after the training program. Mixed-models repeated measures method was used to compare differences between the groups (α = 0.05). After the 10-week intervention period, there was no significant exercise program by time interaction for CTX; however, the percent change for CTX was significantly different between the groups (EG = -13.1 ± 24.4 % vs. CG = 11.0 ± 51.5 %, P < 0.05). While there was no significant change of osteocalcin in both groups. As expected, there was no significant change of BMD in both groups. In addition, the functional fitness components in the EG were significantly improved, as demonstrated by substantial enhancement in both lower- and upper-limb muscular strength and cardiovascular endurance (P < 0.05). The current short-term GBSA exercise benefited to bone metabolism and general health by significantly reduced bone resorption activity and improved

The metabolic cost of an integrated exercise program performed during 14 days of bed rest.

PubMed

Scott, Jessica M; Hackney, Kyle; Downs, Meghan; Guined, Jamie; Ploutz-Snyder, Robert; Fiedler, James; Cunningham, David; Ploutz-Snyder, Lori

2014-06-01

Exercise countermeasures designed to mitigate muscle atrophy during long-duration spaceflight may not be as effective if crewmembers are in negative energy balance (energy output > energy input). This study determined the energy cost of supine exercise (resistance, interval, aerobic) during the spaceflight analogue of bed rest. Nine subjects (eight men and one woman; 34.5 +/- 8.2 yr) completed 14 d of bed rest and concomitant exercise countermeasures. Body mass and basal metabolic rate (BMR) were assessed before and during bed rest. Exercise energy expenditure was measured during and immediately after [excess post-exercise oxygen consumption (EPOC)] each of five different exercise protocols (30-s, 2-min, and 4-min intervals, continuous aerobic, and a variety of resistance exercises) during bed rest. On days when resistance and continuous aerobic exercise were performed daily, energy expenditure was significantly greater (2879 +/- 280 kcal) than 2-min (2390 +/- 237 kcal), 30-s (2501 +/- 264 kcal), or 4-min (2546 +/- 264 kcal) exercise. There were no significant differences in BMR (pre-bed rest: 1649 +/- 216 kcal; week 1: 1632 +/- 174 kcal; week 2:1657 +/- 176 kcal) or body mass (pre-bed rest: 75.2 +/- 10.1 kg; post-bed rest: 75.2 +/- 9.6 kg). These findings highlight the importance of energy balance for long-duration crewmembers completing a high-intensity exercise program with multiple exercise sessions daily.

Is the Veterans Specific Activity Questionnaire Valid to Assess Older Adults Aerobic Fitness?

PubMed

de Carvalho Bastone, Alessandra; de Souza Moreira, Bruno; Teixeira, Claudine Patrícia; Dias, João Marcos Domingues; Dias, Rosângela Corrêa

2016-01-01

Aerobic fitness in older adults is related to health status, incident disability, nursing home admission, and all-cause mortality. The most accurate quantification of aerobic fitness, expressed as peak oxygen consumption in mL·kg·min, is the cardiorespiratory exercise test; however, it is not feasible in all settings and might offer risk to patients. The Veterans Specific Activity Questionnaire (VSAQ) is a 13-item self-administered symptom questionnaire that estimates aerobic fitness expressed in metabolic equivalents (METs) and has been validated to cardiovascular patients. The purpose of this study was to assess the validity and reliability of the VSAQ in older adults without specific health conditions. A methodological study with a cross-sectional design was conducted with 28 older adults (66-86 years). The VSAQ was administered on 3 occasions by 2 evaluators. Aerobic capacity in METs as measured by the VSAQ was compared with the METs found in an incremental shuttle walk test (ISWT) performed with a portable metabolic measurement system and with accelerometer data. The validity of the VSAQ was found to be moderate-to-good when compared with the METs and distance measured by the ISWT and with the moderate activity per day and steps per day obtained by accelerometry. The Bland-Altman graph analysis showed no values outside the limits of agreement, suggesting good precision between the METs estimated by questionnaire and the METs measured by the ISWT. Also, the intrarater and interrater reliabilities of the instrument were good. The results showed that the VSAQ is a valuable tool to assess the aerobic fitness of older adults.

Activity of metabolic enzymes and muscle-specific gene expression in parr and smolts Atlantic salmon Salmo salar L. of different age groups.

PubMed

Churova, Maria V; Meshcheryakova, Olga V; Veselov, Aleksey E; Efremov, Denis A; Nemova, Nina N

2017-08-01

This study was conducted to characterize the energy metabolism level and the features of muscle growth regulation during the development of Atlantic salmon (Salmo salar) inhabiting the Indera River (Kola Peninsula, Russia). The activities of aerobic and anaerobic enzymes (cytochrome c oxidase and lactate dehydrogenase) and carbohydrate metabolism enzymes (glucose-6-phosphate dehydrogenase, glycerol-3-phosphate dehydrogenase, and aldolase) were measured in muscle and liver tissue. Gene expression levels of myosin heavy chain (MyHC), myostatin (MSTN-1a), and myogenic regulatory factors (MRFs-MyoD1a, MyoD1b, MyoD1c, Myf5, myogenin) were measured in the white muscles of salmon parr of ages 0+, 1+, 2+, and 3+ and smolts of ages 2+ and 3+. Multidirectional changes in the activity of enzymes involved in aerobic and anaerobic energy metabolism with age were shown in the white muscles of the parr. The cytochrome c oxidase activity was higher in muscles of underyearlings (0+) and yearlings (1+) and decreased in 2+ and 3+ age groups. The activity of lactate dehydrogenase, in contrast, increased with age. The patterns of changes in expression levels of MyoD1a, MyoD1b, myogenin, MyHC, and MSTN-1a at different ages of the parr were similar. Particularly, the expression of these genes peaked in the yearling parr (1+) and then decreased in elder groups. The differences were revealed in parameters studied between the parr and smolts. The level of aerobic and anaerobic metabolism enzyme activities was higher in the white muscles of smolts than in parr. The activity of carbohydrate metabolism enzymes was decreased in the smolts' livers. The expression levels of MyHC, MyoD1a, MyoD1b, and myogenin were lower in smolts at age 2+ compared to parr. These findings expand our knowledge of age-related and stage-related features of energy metabolism and muscle development regulation in young Atlantic salmon in their natural habitat. The results might be used for monitoring of the salmon

Mitochondrial NDUFS3 regulates the ROS-mediated onset of metabolic switch in transformed cells

PubMed Central

Suhane, Sonal; Kanzaki, Hirotaka; Arumugaswami, Vaithilingaraja; Murali, Ramachandran; Ramanujan, V. Krishnan

2013-01-01

Summary Aerobic glycolysis in transformed cells is an unique metabolic phenotype characterized by a hyperactivated glycolytic pathway even in the presence of oxygen. It is not clear if the onset of aerobic glycolysis is regulated by mitochondrial dysfunction and, if so, what the metabolic windows of opportunity available to control this metabolic switch (mitochondrial to glycolytic) landscape are in transformed cells. Here we report a genetically-defined model system based on the gene-silencing of a mitochondrial complex I subunit, NDUFS3, where we demonstrate the onset of metabolic switch in isogenic human embryonic kidney cells by differential expression of NDUFS3. By means of extensive metabolic characterization, we demonstrate that NDUFS3 gene silencing systematically introduces mitochondrial dysfunction thereby leading to the onset of aerobic glycolysis in a manner dependent on NDUFS3 protein levels. Furthermore, we show that the sustained imbalance in free radical dynamics is a necessary condition to sustain the observed metabolic switch in cell lines with the most severe NDUFS3 suppression. Together, our data reveal a novel role for mitochondrial complex I subunit NDUFS3 in regulating the degree of mitochondrial dysfunction in living cells, thereby setting a “metabolic threshold” for the observation of aerobic glycolysis phenotype within the confines of mitochondrial dysfunction. PMID:23519235

[The biology of aerobic methylobacteria capable of degrading halomethanes].

PubMed

Trotsenko, Iu A; Doronina, N V

2003-01-01

Recent data on the biology of aerobic methylotrophic bacteria capable of utilizing toxic halogenated methane derivatives as sources of carbon and energy are reviewed, with particular emphasis on the taxonomic, physiological, and biochemical diversity of mono- and dihalomethane-degrading methylobacteria and the enzymatic and genetic aspects of their primary metabolism. The initial steps of chloromethane dehalogenation to formate and HCl through a methylated corrinoid and methyletrahydrofolate are catalyzed by inducible cobalamin methyl transferase, made up of two proteins (CmuA and CmuB) encoded by the cmuA and cmuB genes. At the same time, the primary dehalogenation of dichloromethane to formaldehyde and HCl is catalyzed by cytosolic glutathione transferase with S-chloromethylglutathione as an intermediate. The latter enzyme is encoded by the structural dcmA gene and is under the negative control of the regulatory dcmR gene. In spite of considerable progress in the study of halomethane dehalogenation, some aspects concerning the structural and functional organization of this process and its regulation remain unknown, including the mechanisms of halomethane transport, the release of toxic dehalogenation products (S-chloromethylglutathione, CH2O, and HCl) from cells, and the maintenance of intracellular pH. Of particular interest is quantitative evaluation of the ecophysiological role of aerobic methylobacteria in the mineralization of halomethanes and protection of the biosphere from these toxic pollutants.

Bioturbation enhances the aerobic respiration of lake sediments in warming lakes.

PubMed

Baranov, Viktor; Lewandowski, Jörg; Krause, Stefan

2016-08-01

While lakes occupy less than 2% of the total surface of the Earth, they play a substantial role in global biogeochemical cycles. For instance, shallow lakes are important sites of carbon metabolism. Aerobic respiration is one of the important drivers of the carbon metabolism in lakes. In this context, bioturbation impacts of benthic animals (biological reworking of sediment matrix and ventilation of the sediment) on sediment aerobic respiration have previously been underestimated. Biological activity is likely to change over the course of a year due to seasonal changes of water temperatures. This study uses microcosm experiments to investigate how the impact of bioturbation (by Diptera, Chironomidae larvae) on lake sediment respiration changes when temperatures increase. While at 5°C, respiration in sediments with and without chironomids did not differ, at 30°C sediment respiration in microcosms with 2000 chironomids per m(2) was 4.9 times higher than in uninhabited sediments. Our results indicate that lake water temperature increases could significantly enhance lake sediment respiration, which allows us to better understand seasonal changes in lake respiration and carbon metabolism as well as the potential impacts of global warming. © 2016 The Authors.

Bioturbation enhances the aerobic respiration of lake sediments in warming lakes

PubMed Central

Krause, Stefan

2016-01-01

While lakes occupy less than 2% of the total surface of the Earth, they play a substantial role in global biogeochemical cycles. For instance, shallow lakes are important sites of carbon metabolism. Aerobic respiration is one of the important drivers of the carbon metabolism in lakes. In this context, bioturbation impacts of benthic animals (biological reworking of sediment matrix and ventilation of the sediment) on sediment aerobic respiration have previously been underestimated. Biological activity is likely to change over the course of a year due to seasonal changes of water temperatures. This study uses microcosm experiments to investigate how the impact of bioturbation (by Diptera, Chironomidae larvae) on lake sediment respiration changes when temperatures increase. While at 5°C, respiration in sediments with and without chironomids did not differ, at 30°C sediment respiration in microcosms with 2000 chironomids per m2 was 4.9 times higher than in uninhabited sediments. Our results indicate that lake water temperature increases could significantly enhance lake sediment respiration, which allows us to better understand seasonal changes in lake respiration and carbon metabolism as well as the potential impacts of global warming. PMID:27484649

Performance evaluation of an anaerobic/aerobic landfill-based digester using yard waste for energy and compost production

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yazdani, Ramin, E-mail: ryazdani@sbcglobal.net; Civil and Environmental Engineering, University of California, One Shields Avenue, Ghausi Hall, Davis, CA 95616; Barlaz, Morton A., E-mail: barlaz@eos.ncsu.edu

2012-05-15

Highlights: Black-Right-Pointing-Pointer Biochemical methane potential decreased by 83% during the two-stage operation. Black-Right-Pointing-Pointer Net energy produced was 84.3 MWh or 46 kWh per million metric tons (Mg). Black-Right-Pointing-Pointer The average removal efficiency of volatile organic compounds (VOCs) was 96-99%. Black-Right-Pointing-Pointer The average removal efficiency of non-methane organic compounds (NMOCs) was 68-99%. Black-Right-Pointing-Pointer The two-stage batch digester proved to be simple to operate and cost-effective. - Abstract: The objective of this study was to evaluate a new alternative for yard waste management by constructing, operating and monitoring a landfill-based two-stage batch digester (anaerobic/aerobic) with the recovery of energy and compost. Themore » system was initially operated under anaerobic conditions for 366 days, after which the yard waste was aerated for an additional 191 days. Off gas generated from the aerobic stage was treated by biofilters. Net energy recovery was 84.3 MWh, or 46 kWh per million metric tons of wet waste (as received), and the biochemical methane potential of the treated waste decreased by 83% during the two-stage operation. The average removal efficiencies of volatile organic compounds and non-methane organic compounds in the biofilters were 96-99% and 68-99%, respectively.« less

L-carnosine affects the growth of Saccharomyces cerevisiae in a metabolism-dependent manner.

PubMed

Cartwright, Stephanie P; Bill, Roslyn M; Hipkiss, Alan R

2012-01-01

The dipeptide L-carnosine (β-alanyl-L-histidine) has been described as enigmatic: it inhibits growth of cancer cells but delays senescence in cultured human fibroblasts and extends the lifespan of male fruit flies. In an attempt to understand these observations, the effects of L-carnosine on the model eukaryote, Saccharomyces cerevisiae, were examined on account of its unique metabolic properties; S. cerevisiae can respire aerobically, but like some tumor cells, it can also exhibit a metabolism in which aerobic respiration is down regulated. L-Carnosine exhibited both inhibitory and stimulatory effects on yeast cells, dependent upon the carbon source in the growth medium. When yeast cells were not reliant on oxidative phosphorylation for energy generation (e.g. when grown on a fermentable carbon source such as 2% glucose), 10-30 mM L-carnosine slowed growth rates in a dose-dependent manner and increased cell death by up to 17%. In contrast, in media containing a non-fermentable carbon source in which yeast are dependent on aerobic respiration (e.g. 2% glycerol), L-carnosine did not provoke cell death. This latter observation was confirmed in the respiratory yeast, Pichia pastoris. Moreover, when deletion strains in the yeast nutrient-sensing pathway were treated with L-carnosine, the cells showed resistance to its inhibitory effects. These findings suggest that L-carnosine affects cells in a metabolism-dependent manner and provide a rationale for its effects on different cell types.

β-alanine Supplementation Fails to Increase Peak Aerobic Power or Ventilatory Threshold in Aerobically Trained Males.

PubMed

Greer, Beau Kjerulf; Katalinas, Matthew E; Shaholli, Danielle M; Gallo, Paul M

2016-01-01

The purpose of the present study was to determine the effect of 30 days of β-alanine supplementation on peak aerobic power and ventilatory threshold (VT) in aerobically fit males. Fourteen males (28.8 ± 9.8 yrs) were assigned to either a β-alanine (SUPP) or placebo (PLAC) group; groups were matched for VT as it was the primary outcome measure. β-alanine supplementation consisted of 3 g/day for 7 days, and 6 g/day for the remaining 23 days. Before and after the supplementation period, subjects performed a continuous, graded cycle ergometry test to determine VO2 peak and VT. Metabolic data were analyzed using a 2 × 2 ANOVA with repeated measures. Thirty days of β-alanine supplementation (SUPP) did not increase VO2 peak (4.05 ± 0.6 vs. 4.14 ± 0.6 L/min) as compared to the placebo (PLAC) group (3.88 ± 0.2 vs. 3.97 ± 0.2 L/min) (p > .05). VT did not significantly improve in either the SUPP (3.21 ± 0.5 vs. 3.33 ± 0.5 L/min) or PLAC (3.19 ± 0.1 vs. 3.20 ± 0.1 L/min) group (p > .05). In conclusion, 30 days of β-alanine supplementation had no effect on VO2 peak or VT in aerobically trained athletes.

Modulation of mitochondrial metabolism as a biochemical trait in blood feeding organisms: the redox vampire hypothesis redux.

PubMed

Ferreira, Caroline M; Oliveira, Matheus P; Paes, Marcia C; Oliveira, Marcus F

2018-06-01

Hematophagous organisms undergo remarkable metabolic changes during the blood digestion process, increasing fermentative glucose metabolism, and reducing respiratory rates, both consequence of functional mitochondrial remodeling. Here, we review the pathways involved in energy metabolism and mitochondrial functionality in a comparative framework across different hematophagous species, and consider how these processes regulate redox homeostasis during blood digestion. The trend across distinct species indicate that a switch in energy metabolism might represent an important defensive mechanism to avoid the potential harmful interaction of oxidants generated from aerobic energy metabolism with products derived from blood digestion. Indeed, in insect vectors, blood feeding transiently reduces respiratory rates and oxidant production, irrespective of tissue and insect model. On the other hand, a different scenario is observed in several unrelated parasite species when exposed to blood digestion products, as respiratory rates reduce and mitochondrial oxidant production increase. The emerging picture indicates that re-wiring of energy metabolism, through reduced mitochondrial function, culminates in improved tolerance to redox insults and seems to represent a key step for hematophagous organisms to cope with the overwhelming and potentially toxic blood meal. © 2018 International Federation for Cell Biology.

Metabolic Reprogramming in Glioma

PubMed Central

Strickland, Marie; Stoll, Elizabeth A.

2017-01-01

Many cancers have long been thought to primarily metabolize glucose for energy production—a phenomenon known as the Warburg Effect, after the classic studies of Otto Warburg in the early twentieth century. Yet cancer cells also utilize other substrates, such as amino acids and fatty acids, to produce raw materials for cellular maintenance and energetic currency to accomplish cellular tasks. The contribution of these substrates is increasingly appreciated in the context of glioma, the most common form of malignant brain tumor. Multiple catabolic pathways are used for energy production within glioma cells, and are linked in many ways to anabolic pathways supporting cellular function. For example: glycolysis both supports energy production and provides carbon skeletons for the synthesis of nucleic acids; meanwhile fatty acids are used both as energetic substrates and as raw materials for lipid membranes. Furthermore, bio-energetic pathways are connected to pro-oncogenic signaling within glioma cells. For example: AMPK signaling links catabolism with cell cycle progression; mTOR signaling contributes to metabolic flexibility and cancer cell survival; the electron transport chain produces ATP and reactive oxygen species (ROS) which act as signaling molecules; Hypoxia Inducible Factors (HIFs) mediate interactions with cells and vasculature within the tumor environment. Mutations in the tumor suppressor p53, and the tricarboxylic acid cycle enzymes Isocitrate Dehydrogenase 1 and 2 have been implicated in oncogenic signaling as well as establishing metabolic phenotypes in genetically-defined subsets of malignant glioma. These pathways critically contribute to tumor biology. The aim of this review is two-fold. Firstly, we present the current state of knowledge regarding the metabolic strategies employed by malignant glioma cells, including aerobic glycolysis; the pentose phosphate pathway; one-carbon metabolism; the tricarboxylic acid cycle, which is central to amino acid

Targeting metabolic pathways for head and neck cancers therapeutics.

PubMed

Yamamoto, Masashi; Inohara, Hidenori; Nakagawa, Takashi

2017-09-01

Cancer cells have distinctive energy metabolism pathways that support their rapid cell division. The preference for anaerobic glycolysis under the normal oxygen condition is known as the Warburg effect and has been observed in head and neck cancers. These metabolic changes are controlled by cancer-related transcription factors, such as tumor suppressor gene and hypoxia inducible factor 1α. In addition, various metabolic enzymes also actively regulate cancer-specific metabolism including the switch between aerobic and anaerobic glycolysis. For a long time, these metabolic changes in cancer cells have been considered a consequence of transformation required to maintain the high rate of tumor cell replication. However, recent studies indicate that alteration of metabolism is sufficient to initiate tumor transformation. Indeed, oncogenic mutations in the metabolic enzymes, isocitrate dehydrogenase and succinate dehydrogenase, have been increasingly found in various cancers, including head and neck cancers. In the present review, we introduce recent findings regarding the cancer metabolism, including the molecular mechanisms of how they affect cancer pathogenesis and maintenance. We also discuss the current and future perspectives on therapeutics that target metabolic pathways, with an emphasis on head and neck cancer.

Progressive hypoxia decouples activity and aerobic performance of skate embryos

PubMed Central

Di Santo, Valentina; Tran, Anna H.; Svendsen, Jon C.

2016-01-01

Although fish population size is strongly affected by survival during embryonic stages, our understanding of physiological responses to environmental stressors is based primarily on studies of post-hatch fishes. Embryonic responses to acute exposure to changes in abiotic conditions, including increase in hypoxia, could be particularly important in species exhibiting long developmental time, as embryos are unable to select a different environment behaviourally. Given that oxygen is key to metabolic processes in fishes and aquatic hypoxia is becoming more severe and frequent worldwide, organisms are expected to reduce their aerobic performance. Here, we examined the metabolic and behavioural responses of embryos of a benthic elasmobranch fish, the little skate (Leucoraja erinacea), to acute progressive hypoxia, by measuring oxygen consumption and movement (tail-beat) rates inside the egg case. Oxygen consumption rates were not significantly affected by ambient oxygen levels until reaching 45% air saturation (critical oxygen saturation, Scrit). Below Scrit, oxygen consumption rates declined rapidly, revealing an oxygen conformity response. Surprisingly, we observed a decoupling of aerobic performance and activity, as tail-beat rates increased, rather than matching the declining metabolic rates, at air saturation levels of 55% and below. These results suggest a significantly divergent response at the physiological and behavioural levels. While skate embryos depressed their metabolic rates in response to progressive hypoxia, they increased water circulation inside the egg case, presumably to restore normoxic conditions, until activity ceased abruptly around 9.8% air saturation. PMID:27293746

Progressive hypoxia decouples activity and aerobic performance of skate embryos.

PubMed

Di Santo, Valentina; Tran, Anna H; Svendsen, Jon C

2016-01-01

Although fish population size is strongly affected by survival during embryonic stages, our understanding of physiological responses to environmental stressors is based primarily on studies of post-hatch fishes. Embryonic responses to acute exposure to changes in abiotic conditions, including increase in hypoxia, could be particularly important in species exhibiting long developmental time, as embryos are unable to select a different environment behaviourally. Given that oxygen is key to metabolic processes in fishes and aquatic hypoxia is becoming more severe and frequent worldwide, organisms are expected to reduce their aerobic performance. Here, we examined the metabolic and behavioural responses of embryos of a benthic elasmobranch fish, the little skate (Leucoraja erinacea), to acute progressive hypoxia, by measuring oxygen consumption and movement (tail-beat) rates inside the egg case. Oxygen consumption rates were not significantly affected by ambient oxygen levels until reaching 45% air saturation (critical oxygen saturation, S crit). Below S crit, oxygen consumption rates declined rapidly, revealing an oxygen conformity response. Surprisingly, we observed a decoupling of aerobic performance and activity, as tail-beat rates increased, rather than matching the declining metabolic rates, at air saturation levels of 55% and below. These results suggest a significantly divergent response at the physiological and behavioural levels. While skate embryos depressed their metabolic rates in response to progressive hypoxia, they increased water circulation inside the egg case, presumably to restore normoxic conditions, until activity ceased abruptly around 9.8% air saturation.

Resistance exercise and aerobic exercise when paired with dietary energy restriction both reduce the clinical components of metabolic syndrome in previously physically inactive males.

PubMed

Potteiger, Jeffrey A; Claytor, Randal P; Hulver, Mathew W; Hughes, Michael R; Carper, Michael J; Richmond, Scott; Thyfault, John P

2012-06-01

The purpose of this study was to compare resistance exercise training (RT) to aerobic exercise training (AE) on the clinical risk factors for metabolic syndrome (MetSyn) in physically inactive overweight males (age 27-48 years). Subjects with at least one risk factor for MetSyn performed RT (n = 13, age 35.1 ± 4.7 years, BMI 31.2 ± 2.7 kg/m(2)) or AE (n = 9, age 37.6 ± 4.9 years, BMI, 31.2 ± 3.2 kg/m(2)) for 6 months. Training frequency and exercise session duration were equal and by 3 months the subjects exercised 4 day/week for 45 min/session. Blood lipids and glucose, waist circumference, and mean arterial blood pressure (MAP) were measured at 0, 3, and 6 months. A MetSyn z score was calculated for each subject from triglycerides, HDL cholesterol, fasting glucose, waist circumference, and MAP. Statistical significance was set at p ≤ 0.05. No significant differences existed between RT and AE groups at 0 month. AE showed a significant reduction in MetSyn z score from 0 (0.91 ± 3.57) to 6 months (-1.35 ± 2.95), while RT approached significance (p = 0.07) from 0 (0.09 ± 2.62) to 6 months (-1.30 ± 2.22). Triglycerides (mmol/L) significantly decreased in AE from 0 (1.93 ± 0.90) to 6 months (1.41 ± 0.70). Waist circumference (cm) significantly decreased in AE from 0 (106.8 ± 7.3) to 6 months (101.2 ± 6.5), and in RT from 0 (108.4 ± 9.0) to 6 months (105.7 ± 7.0). MAP (mmHg) decreased in RT from 0 (93.8 ± 5.8) to 6 months (87.5 ± 6.1) and in AE from 0 (97.6 ± 7.0) to 6 months (91.3 ± 6.8). With equal training frequency and exercise session duration, both RT and AE training, when paired with energy restriction improve the clinical risk factor profile for MetSyn.

Metabolomics reveals the key role of oxygen metabolism in the heat susceptibility of an alpine dwelling ghost moth, Thitarodes xiaojinensis (Lepidoptera: Hepialidae).

PubMed

Zhu, Wei; Meng, Qian; Zhang, Huan; Wang, Meng-Long; Li, Xuan; Wang, Hong-Tuo; Zhou, Gui-Ling; Miao, Lin; Qin, Qi-Lian; Zhang, Ji-Hong

2018-05-23

Ghost moths inhabiting the alpine meadows of the Tibetan Plateau are cold-adapted stenothermal organisms that are susceptible to heat (dead within 7 days of 27 °C exposure). Exploring the metabolic basis of their heat susceptibility would extend our understanding of the thermal biology of alpine dwelling invertebrates. Here, gas chromatography-mass spectrometry-based metabolomics was combined with physiological and transcriptional approaches to determine the metabolic mechanisms of heat susceptibility in Thitarodes xiaojinensis larvae. The metabolomics results showed that 27 °C heat stress impaired the Krebs cycle and lipolysis in T. xiaojinensis larvae, as demonstrated by the accumulation of intermediary metabolites. In addition, carbohydrate reserves were highly and exclusively consumed, and an anaerobic product, lactate, accumulated. This evidence suggested a strong reliance on glycolysis to generate energy anaerobically. The respiration rate and enzymatic activity test results indicated a deficiency in O 2 metabolism; in addition, the Krebs cycle capacity was not lowered, and the metabolic flux through aerobic pathways was limited. These findings were further supported by the occurrence of hypoxia symptoms in midgut mitochondria (vacuolation and swelling) and increased transcription of hypoxia-induced factor 1-α. Overall, heat stress caused O 2 limitation and depressed the overall intensity of aerobic metabolism in ghost moths, and less efficient anaerobic glycolysis was activated to sustain their energy supply. After the carbohydrates became limited, the energy supply became deficient. Our study presented a comprehensive metabolic explanation for the heat susceptibility of ghost moths and revealed the relationship between O 2 metabolism and heat susceptibility in these larvae. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Sugar Metabolism in Hummingbirds and Nectar Bats.

PubMed

Suarez, Raul K; Welch, Kenneth C

2017-07-12

Hummingbirds and nectar bats coevolved with the plants they visit to feed on floral nectars rich in sugars. The extremely high metabolic costs imposed by small size and hovering flight in combination with reliance upon sugars as their main source of dietary calories resulted in convergent evolution of a suite of structural and functional traits. These allow high rates of aerobic energy metabolism in the flight muscles, fueled almost entirely by the oxidation of dietary sugars, during flight. High intestinal sucrase activities enable high rates of sucrose hydrolysis. Intestinal absorption of glucose and fructose occurs mainly through a paracellular pathway. In the fasted state, energy metabolism during flight relies on the oxidation of fat synthesized from previously-ingested sugar. During repeated bouts of hover-feeding, the enhanced digestive capacities, in combination with high capacities for sugar transport and oxidation in the flight muscles, allow the operation of the "sugar oxidation cascade", the pathway by which dietary sugars are directly oxidized by flight muscles during exercise. It is suggested that the potentially harmful effects of nectar diets are prevented by locomotory exercise, just as in human hunter-gatherers who consume large quantities of honey.

Carbon, nitrogen and phosphorus removal mechanisms of aerobic granules.

PubMed

Sarma, Saurabh Jyoti; Tay, Joo-Hwa

2018-04-10

Aerobic granules are the potential tools to develop modern wastewater treatment technologies with improved nutrient removal efficiency. These granules have several promising advantages over conventional activated sludge-based wastewater treatment processes. This technology has the potential of reducing the infrastructure and operation costs of wastewater treatment by 25%, energy requirement by 30%, and space requirement by 75%. The nutrient removal mechanisms of aerobic granules are slightly different from that of the activated sludge. For instance, unlike activated sludge process, according to some reports, as high as 70% of the total phosphorus removed by aerobic granules were attributed to precipitation within the granules. Similarly, aerobic granule-based technology reduces the total amount of sludge produced during wastewater treatment. However, the reason behind this observation is unknown and it needs further explanations based on carbon and nitrogen removal mechanisms. Thus, as a part of the present review, a set of new hypotheses have been proposed to explain the peculiar nutrient removal mechanisms of the aerobic granules.

Energy metabolism in astrocytes and neurons treated with manganese: relation among cell-specific energy failure, glucose metabolism, and intercellular trafficking using multinuclear NMR-spectroscopic analysis.

PubMed

Zwingmann, Claudia; Leibfritz, Dieter; Hazell, Alan S

2003-06-01

A central question in manganese neurotoxicity concerns mitochondrial dysfunction leading to cerebral energy failure. To obtain insight into the underlying mechanism(s), the authors investigated cell-specific pathways of [1-13C]glucose metabolism by high-resolution multinuclear NMR-spectroscopy. Five-day treatment of neurons with 100-micro mol/L MnCl(2) led to 50% and 70% decreases of ATP/ADP and phosphocreatine-creatine ratios, respectively. An impaired flux of [1-13C]glucose through pyruvate dehydrogenase, which was associated with Krebs cycle inhibition and hence depletion of [4-13C]glutamate, [2-13C]GABA, and [13C]glutathione, hindered the ability of neurons to compensate for mitochondrial dysfunction by oxidative glucose metabolism and further aggravated neuronal energy failure. Stimulated glycolysis and oxidative glucose metabolism protected astrocytes against energy failure and oxidative stress, leading to twofold increased de novo synthesis of [3-13C]lactate and fourfold elevated [4-13C]glutamate and [13C]glutathione levels. Manganese, however, inhibited the synthesis and release of glutamine. Comparative NMR data obtained from cocultures showed disturbed astrocytic function and a failure of astrocytes to provide neurons with substrates for energy and neurotransmitter metabolism, leading to deterioration of neuronal antioxidant capacity (decreased glutathione levels) and energy metabolism. The results suggest that, concomitant to impaired neuronal glucose oxidation, changes in astrocytic metabolism may cause a loss of intercellular homeostatic equilibrium, contributing to neuronal dysfunction in manganese neurotoxicity.

Durations and domains of daily aerobic activity: evidence from the 2010 Canadian time-use survey.

PubMed

Millward, Hugh; Spinney J, E L; Scott, Darren

2014-07-01

This study employs national time-diary data to evaluate how much aerobic activity Canadians engage in on a daily basis, how that activity is apportioned by activity domain, and how subgroups within the population vary in their aerobic attainment. The study employs time-use data from the 2010 General Social Survey of Canada, for 15,390 respondents aged 15 and older. To estimate effort levels, the authors harmonized survey codes with those in the Compendium of Physical Activities. Aerobic activity was defined as moderate or vigorous effort at 3.5 Metabolic Equivalent of Task (MET) or higher. Among the 4 activity domains, aerobic participation is highest in leisure activities, followed by chores, paid work, and active transportation (AT). Only a minority (42%) of respondents recorded at least 20 mins/day of aerobic activity. Aerobic totals were particularly low for women and those in poor or fair health, and low for students, 15- to 24-year-olds, and those residing in Quebec, Ontario, and larger cities. The majority of Canadian adults are failing to meet recommended aerobic activity levels. However, there is considerable opportunity to increase aerobic participation for some groups, particularly women and young adults, especially in the leisure and AT domains.

Tributyltin disrupts feeding and energy metabolism in the goldfish (Carassius auratus).

PubMed

Zhang, Jiliang; Sun, Ping; Yang, Fan; Kong, Tao; Zhang, Ruichen

2016-06-01

Tributyltin (TBT) can induce obesogen response. However, little is known about the adverse effects of TBT on food intake and energy metabolism. The present study was designed to investigate the effects of TBT, at environmental concentrations of 2.44 and 24.4 ng/L (1 and 10 ng/L as Sn), on feeding and energy metabolism in goldfish (Carassius auratus). After exposure for 54 d, TBT increased the weight gain and food intake in fish. The patterns of brain neuropeptide genes expression were in line with potential orexigenic effects, with increased expression of neuropeptide Y and apelin, and decreased expression of pro-opiomelanocortin, ghrelin, cocaine and amphetamine-regulated transcript, and corticotropin-releasing factor. Interestingly, the energy metabolism indicators (oxygen consumption, ammonia exertion and swimming activity) and the serum thyroid hormones were all significantly increased at the 2.44 ng/L TBT group in fish. However, no changes of energy metabolism indicators or a decrease of thyroid hormones was found at the 24.4 ng/L TBT group, which indicated a complex disrupting effect on metabolism of TBT. In short, TBT can alter feeding and energy metabolism in fish, which might promote the obesogenic responses. Copyright © 2016 Elsevier Ltd. All rights reserved.

Energy metabolism and nutritional status in hospitalized patients with lung cancer.

PubMed

Takemura, Yumi; Sasaki, Masaya; Goto, Kenichi; Takaoka, Azusa; Ohi, Akiko; Kurihara, Mika; Nakanishi, Naoko; Nakano, Yasutaka; Hanaoka, Jun

2016-09-01

This study aimed to investigate the energy metabolism of patients with lung cancer and the relationship between energy metabolism and proinflammatory cytokines. Twenty-eight patients with lung cancer and 18 healthy controls were enrolled in this study. The nutritional status upon admission was analyzed using nutritional screening tools and laboratory tests. The resting energy expenditure and respiratory quotient were measured using indirect calorimetry, and the predicted resting energy expenditure was calculated using the Harris-Benedict equation. Energy expenditure was increased in patients with advanced stage disease, and there were positive correlations between measured resting energy expenditure/body weight and interleukin-6 levels and between measured resting energy expenditure/predicted resting energy expenditure and interleukin-6 levels. There were significant relationships between body mass index and plasma leptin or acylated ghrelin levels. However, the level of appetite controlling hormones did not affect dietary intake. There was a negative correlation between plasma interleukin-6 levels and dietary intake, suggesting that interleukin-6 plays a role in reducing dietary intake. These results indicate that energy expenditure changes significantly with lung cancer stage and that plasma interleukin-6 levels affect energy metabolism and dietary intake. Thus, nutritional management that considers the changes in energy metabolism is important in patients with lung cancer.

Co(salophen)-Catalyzed Aerobic Oxidation of p-Hydroquinone: Mechanism and Implications for Aerobic Oxidation Catalysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anson, Colin W.; Ghosh, Soumya; Hammes-Schiffer, Sharon

2016-03-30

Macrocyclic metal complexes and p-benzoquinones are commonly used as co-catalytic redox mediators in aerobic oxidation reactions. In an effort to gain insight into the mechanism and energetic efficiency of these reactions, we investigated Co(salophen)-catalyzed aerobic oxidation of p-hydroquinone. Kinetic and spectroscopic data suggest that the catalyst resting-state consists of an equilibrium between a CoII(salophen) complex, a CoIII-superoxide adduct, and a hydrogen-bonded adduct between the hydroquinone and the CoIII–O2 species. The kinetic data, together with density functional theory data, suggest that the turnover-limiting step features proton-coupled electron transfer from a semi-hydroquinone species and a CoIII-hydroperoxide intermediate. Additional experimental and computational datamore » suggest that a coordinated H2O2 intermediate oxidizes a second equivalent of hydroquinone. This research was supported as part of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center, funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences. The NSF provided partial support for the EPR instrumentation (NSF CHE-0741901).« less

Adaptive Evolution of Mitochondrial Energy Metabolism Genes Associated with Increased Energy Demand in Flying Insects

PubMed Central

Yang, Yunxia; Xu, Shixia; Xu, Junxiao; Guo, Yan; Yang, Guang

2014-01-01

Insects are unique among invertebrates for their ability to fly, which raises intriguing questions about how energy metabolism in insects evolved and changed along with flight. Although physiological studies indicated that energy consumption differs between flying and non-flying insects, the evolution of molecular energy metabolism mechanisms in insects remains largely unexplored. Considering that about 95% of adenosine triphosphate (ATP) is supplied by mitochondria via oxidative phosphorylation, we examined 13 mitochondrial protein-encoding genes to test whether adaptive evolution of energy metabolism-related genes occurred in insects. The analyses demonstrated that mitochondrial DNA protein-encoding genes are subject to positive selection from the last common ancestor of Pterygota, which evolved primitive flight ability. Positive selection was also found in insects with flight ability, whereas no significant sign of selection was found in flightless insects where the wings had degenerated. In addition, significant positive selection was also identified in the last common ancestor of Neoptera, which changed its flight mode from direct to indirect. Interestingly, detection of more positively selected genes in indirect flight rather than direct flight insects suggested a stronger selective pressure in insects having higher energy consumption. In conclusion, mitochondrial protein-encoding genes involved in energy metabolism were targets of adaptive evolution in response to increased energy demands that arose during the evolution of flight ability in insects. PMID:24918926

Adaptive evolution of mitochondrial energy metabolism genes associated with increased energy demand in flying insects.

PubMed

Yang, Yunxia; Xu, Shixia; Xu, Junxiao; Guo, Yan; Yang, Guang

2014-01-01

Insects are unique among invertebrates for their ability to fly, which raises intriguing questions about how energy metabolism in insects evolved and changed along with flight. Although physiological studies indicated that energy consumption differs between flying and non-flying insects, the evolution of molecular energy metabolism mechanisms in insects remains largely unexplored. Considering that about 95% of adenosine triphosphate (ATP) is supplied by mitochondria via oxidative phosphorylation, we examined 13 mitochondrial protein-encoding genes to test whether adaptive evolution of energy metabolism-related genes occurred in insects. The analyses demonstrated that mitochondrial DNA protein-encoding genes are subject to positive selection from the last common ancestor of Pterygota, which evolved primitive flight ability. Positive selection was also found in insects with flight ability, whereas no significant sign of selection was found in flightless insects where the wings had degenerated. In addition, significant positive selection was also identified in the last common ancestor of Neoptera, which changed its flight mode from direct to indirect. Interestingly, detection of more positively selected genes in indirect flight rather than direct flight insects suggested a stronger selective pressure in insects having higher energy consumption. In conclusion, mitochondrial protein-encoding genes involved in energy metabolism were targets of adaptive evolution in response to increased energy demands that arose during the evolution of flight ability in insects.

Aerobic exercise regulates blood lipid and insulin resistance via the toll‑like receptor 4‑mediated extracellular signal‑regulated kinases/AMP‑activated protein kinases signaling pathway.

PubMed

Wang, Mei; Li, Sen; Wang, Fubaihui; Zou, Jinhui; Zhang, Yanfeng

2018-06-01

Diabetes mellitus is a complicated metabolic disease with symptoms of hyperglycemia, insulin resistance, chronic damage and dysfunction of tissues, and metabolic syndrome for insufficient insulin production. Evidence has indicated that exercise treatments are essential in the progression of type‑ІІ diabetes mellitus, and affect insulin resistance and activity of islet β‑cells. In the present study, the efficacy and signaling mechanism of aerobic exercise on blood lipids and insulin resistance were investigated in the progression of type‑ІІ diabetes mellitus. Body weight, glucose metabolism and insulin serum levels were investigated in mouse models of type‑ІІ diabetes mellitus following experienced aerobic exercise. Expression levels of inflammatory factors, interleukin (IL)‑6, high‑sensitivity C‑reactive protein, tumor necrosis factor‑α and leucocyte differentiation antigens, soluble CD40 ligand in the serum were analyzed in the experimental mice. In addition, expression levels of toll‑like receptor 4 (TLR‑4) were analyzed in the liver cells of experimental mice. Changes of oxidative stress indicators, including reactive oxygen species, superoxide dismutase, glutathione and catalase were examined in the liver cells of experimental mice treated by aerobic exercise. Expression levels and activity of extracellular signal‑regulated kinases (ERK) and AMP‑activated protein kinase (AMPK) signaling pathways were investigated in the liver cells of mouse models of type‑ІІ diabetes mellitus after undergoing aerobic exercise. Aerobic exercise decreased the expression levels of inflammatory factors in the serum of mouse models of type‑ІІ diabetes mellitus. The results indicated that aerobic exercise downregulated oxidative stress indicators in liver cells from mouse models of type‑ІІ diabetes mellitus. In addition, the ERK and AMPK signaling pathways were inactivated by aerobic exercise in liver cells in mouse models of type�

[Lipid and metabolic profiles in adolescents are affected more by physical fitness than physical activity (AVENA study)].

PubMed

García-Artero, Enrique; Ortega, Francisco B; Ruiz, Jonatan R; Mesa, José L; Delgado, Manuel; González-Gross, Marcela; García-Fuentes, Miguel; Vicente-Rodríguez, Germán; Gutiérrez, Angel; Castillo, Manuel J

2007-06-01

To determine whether the level of physical activity or physical fitness (i.e., aerobic capacity and muscle strength) in Spanish adolescents influences lipid and metabolic profiles. From a total of 2859 Spanish adolescents (age 13.0-18.5 years) taking part in the AVENA (Alimentación y Valoración del Estado Nutricional en Adolescentes) study, 460 (248 male, 212 female) were randomly selected for blood analysis. Their level of physical activity was determined by questionnaire. Aerobic capacity was assessed using the Course-Navette test. Muscle strength was evaluated using manual dynamometry, the long jump test, and the flexed arm hang test. A lipid-metabolic cardiovascular risk index was derived from the levels of triglycerides, low-density lipoprotein cholesterol (LDLC), high-density lipoprotein cholesterol (HDLC), and glucose. No relationship was found between the level of physical activity and lipid-metabolic index in either sex. In contrast, there was an inverse relationship between the lipid-metabolic index and aerobic capacity in males (P=.003) after adjustment for physical activity level and muscle strength. In females, a favorable lipid-metabolic index was associated with greater muscle strength (P=.048) after adjustment for aerobic capacity. These results indicate that, in adolescents, physical fitness, and not physical activity, is related to lipid and metabolic cardiovascular risk. Higher aerobic capacity in males and greater muscle strength in females were associated with lower lipid and metabolic risk factors for cardiovascular disease.

Partitioning the metabolic scope: the importance of anaerobic metabolism and implications for the oxygen- and capacity-limited thermal tolerance (OCLTT) hypothesis

PubMed Central

Ejbye-Ernst, Rasmus; Michaelsen, Thomas Y.; Tirsgaard, Bjørn; Wilson, Jonathan M.; Jensen, Lasse F.; Steffensen, John F.; Pertoldi, Cino; Aarestrup, Kim; Svendsen, Jon C.

2016-01-01

Ongoing climate change is predicted to affect the distribution and abundance of aquatic ectotherms owing to increasing constraints on organismal physiology, in particular involving the metabolic scope (MS) available for performance and fitness. The oxygen- and capacity-limited thermal tolerance (OCLTT) hypothesis prescribes MS as an overarching benchmark for fitness-related performance and assumes that any anaerobic contribution within the MS is insignificant. The MS is typically derived from respirometry by subtracting standard metabolic rate from the maximal metabolic rate; however, the methodology rarely accounts for anaerobic metabolism within the MS. Using gilthead sea bream (Sparus aurata) and Trinidadian guppy (Poecilia reticulata), this study tested for trade-offs (i) between aerobic and anaerobic components of locomotor performance; and (ii) between the corresponding components of the MS. Data collection involved measuring oxygen consumption rate at increasing swimming speeds, using the gait transition from steady to unsteady (burst-assisted) swimming to detect the onset of anaerobic metabolism. Results provided evidence of the locomotor performance trade-off, but only in S. aurata. In contrast, both species revealed significant negative correlations between aerobic and anaerobic components of the MS, indicating a trade-off where both components of the MS cannot be optimized simultaneously. Importantly, the fraction of the MS influenced by anaerobic metabolism was on average 24.3 and 26.1% in S. aurata and P. reticulata, respectively. These data highlight the importance of taking anaerobic metabolism into account when assessing effects of environmental variation on the MS, because the fraction where anaerobic metabolism occurs is a poor indicator of sustainable aerobic performance. Our results suggest that without accounting for anaerobic metabolism within the MS, studies involving the OCLTT hypothesis could overestimate the metabolic scope available for

Effect of desipramine and fluoxetine on energy metabolism of cerebral mitochondria.

PubMed

Villa, Roberto Federico; Ferrari, Federica; Gorini, Antonella; Brunello, Nicoletta; Tascedda, Fabio

2016-08-25

Brain bioenergetic abnormalities in mood disorders were detected by neuroimaging in vivo studies in humans. Because of the increasing importance of mitochondrial pathogenetic hypothesis of Depression, in this study the effects of sub-chronic treatment (21days) with desipramine (15mg/kg) and fluoxetine (10mg/kg) were evaluated on brain energy metabolism. On mitochondria in vivo located in neuronal soma (somatic) and on mitochondria of synapses (synaptic), the catalytic activities of regulatory enzymes of mitochondrial energy-yielding metabolic pathways were assayed. Antidepressants in vivo treatment modified the activities of selected enzymes of different mitochondria, leading to metabolic modifications in the energy metabolism of brain cortex: (a) the enhancement of cytochrome oxidase activity on somatic mitochondria; (b) the decrease of malate, succinate dehydrogenase and glutamate-pyruvate transaminase activities of synaptic mitochondria; (c) the selective effect of fluoxetine on enzymes related to glutamate metabolism. These results overcome the conflicting data so far obtained with antidepressants on brain energy metabolism, because the enzymatic analyses were made on mitochondria with diversified neuronal in vivo localization, i.e. on somatic and synaptic. This research is the first investigation on the pharmacodynamics of antidepressants studied at subcellular level, in the perspective of (i) assessing the role of energy metabolism of cerebral mitochondria in animal models of mood disorders, and (ii) highlighting new therapeutical strategies for antidepressants targeting brain bioenergetics. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

Loss of Abhd5 Promotes Colorectal Tumor Development and Progression by Inducing Aerobic Glycolysis and Epithelial-Mesenchymal Transition

PubMed Central

Ou, Juanjuan; Miao, Hongming; Ma, Yinyan; Guo, Feng; Deng, Jia; Wei, Xing; Zhou, Jie; Xie, Ganfeng; Shi, Hang; Xue, Bingzhong; Liang, Houjie; Yu, Liqing

2014-01-01

SUMMARY How cancer cells shift metabolism to aerobic glycolysis is largely unknown. Here we show that deficiency of α/β-hydrolase domain-containing-5 (Abhd5), an intracellular lipolytic activator that is also known as comparative gene identification-58 (CGI-58), promotes this metabolic shift and enhances malignancies of colorectal carcinomas (CRCs). Silencing of Abhd5 in normal fibroblasts induces malignant transformation. Intestine-specific knockout of Abhd5 in ApcMin/+ mice robustly increases tumorigenesis and malignant transformation of adenomatous polyps. In colon cancer cells, Abhd5 deficiency induces epithelial-mesenchymal transition by suppressing the AMPKα-p53 pathway, which is attributable to increased aerobic glycolysis. In human CRCs, Abhd5 expression falls substantially and correlates negatively with malignant features. Our study is the first to link Abhd5 to CRC pathogenesis. It suggests that cancer cells may develop aerobic glycolysis by suppressing Abhd5-mediated intracellular lipolysis. PMID:25482557

The effect of temperature on the resting and post-exercise metabolic rates and aerobic metabolic scope in shortnose sturgeon Acipenser brevirostrum.

PubMed

Zhang, Yueyang; Kieffer, James D

2017-10-01

The effects of acclimation temperature (15, 20, 25 °C) on routine oxygen consumption and post-exercise maximal oxygen consumption rates (MO 2 ) were measured in juvenile shortnose sturgeon (Acipenser brevirostrum LeSueur, 1818). The routine MO 2 of shortnose sturgeon increased significantly from 126.75 mg O 2  h -1  kg -1 at 15 °C to 253.13 mg O 2  h -1  kg -1 at 25 °C. The temperature coefficient (Q 10 ) values of the routine metabolic rates ranged between 1.61 and 2.46, with the largest Q 10 values occurring between 15 and 20 °C. The average post-exercise MO 2 of all temperature groups increased to a peak value immediately following the exercise, with levels increasing about 2-fold among all temperature groups. The Q 10 values for post-exercise MO 2 ranged from 1.21 to 2.12, with the highest difference occurring between 15 and 20 °C. Post-exercise MO 2 values of shortnose sturgeon in different temperature groups all decreased exponentially and statistically returned to pre-exercise (resting) levels by 30 min at 15 and 20 °C and by 60 min at 25 °C. The aerobic metabolic scope (post-exercise maximal MO 2 -routine MO 2 ) increased to a maximum value ∼156 mg O 2  h -1  kg -1 at intermediate experimental temperatures (i.e., 20 °C) and then decreased as the temperature increased to 25 °C. However, this trend was not significant. The results suggest that juvenile shortnose sturgeon show flexibility in their ability to adapt to various temperature environments and in their responses to exhaustive exercise.

Performance of sequential anaerobic/aerobic digestion applied to municipal sewage sludge.

PubMed

Tomei, M Concetta; Rita, Sara; Mininni, Giuseppe

2011-07-01

A promising alternative to conventional single phase processing, the use of sequential anaerobic-aerobic digestion, was extensively investigated on municipal sewage sludge from a full scale wastewater treatment plant. The objective of the work was to evaluate sequential digestion performance by testing the characteristics of the digested sludge in terms of volatile solids (VS), Chemical Oxygen Demand (COD) and nitrogen reduction, biogas production, dewaterability and the content of proteins and polysaccharides. VS removal efficiencies of 32% in the anaerobic phase and 17% in the aerobic one were obtained, and similar COD removal efficiencies (29% anaerobic and 21% aerobic) were also observed. The aerobic stage was also efficient in nitrogen removal providing a decrease of the nitrogen content in the supernatant attributable to nitrification and simultaneous denitrification. Moreover, in the aerobic phase an additional marked removal of proteins and polysaccharides produced in the anaerobic phase was achieved. The sludge dewaterability was evaluated by determining the Optimal Polymer Dose (OPD) and the Capillary Suction Time (CST) and a significant positive effect due to the aerobic stage was observed. Biogas production was close to the upper limit of the range of values reported in the literature in spite of the low anaerobic sludge retention time of 15 days. From a preliminary analysis it was found that the energy demand of the aerobic phase was significantly lower than the recovered energy in the anaerobic phase and the associated additional cost was negligible in comparison to the saving derived from the reduced amount of sludge to be disposed. Copyright © 2011 Elsevier Ltd. All rights reserved.

Cold adaptation mechanisms in the ghost moth Hepialus xiaojinensis: Metabolic regulation and thermal compensation.

PubMed

Zhu, Wei; Zhang, Huan; Li, Xuan; Meng, Qian; Shu, Ruihao; Wang, Menglong; Zhou, Guiling; Wang, Hongtuo; Miao, Lin; Zhang, Jihong; Qin, Qilian

2016-02-01

Ghost moths (Lepidoptera: Hepialidae) are cold-adapted stenothermal species inhabiting alpine meadows on the Tibetan Plateau. They have an optimal developmental temperature of 12-16 °C but can maintain feeding and growth at 0 °C. Their survival strategies have received little attention, but these insects are a promising model for environmental adaptation. Here, biochemical adaptations and energy metabolism in response to cold were investigated in larvae of the ghost moth Hepialus xiaojinensis. Metabolic rate and respiratory quotient decreased dramatically with decreasing temperature (15-4 °C), suggesting that the energy metabolism of ghost moths, especially glycometabolism, was sensitive to cold. However, the metabolic rate at 4 °C increased with the duration of cold exposure, indicating thermal compensation to sustain energy budgets under cold conditions. Underlying regulation strategies were studied by analyzing metabolic differences between cold-acclimated (4 °C for 48 h) and control larvae (15 °C). In cold-acclimated larvae, the energy generating pathways of carbohydrates, instead of the overall consumption of carbohydrates, was compensated in the fat body by improving the transcription of related enzymes. The mobilization of lipids was also promoted, with higher diacylglycerol, monoacylglycerol and free fatty acid content in hemolymph. These results indicated that cold acclimation induced a reorganization on metabolic structure to prioritise energy metabolism. Within the aerobic process, flux throughout the tricarboxylic acid (TCA) cycle was encouraged in the fat body, and the activity of α-ketoglutarate dehydrogenase was the likely compensation target. Increased mitochondrial cristae density was observed in the midgut of cold-acclimated larvae. The thermal compensation strategies in this ghost moth span the entire process of energy metabolism, including degration of metabolic substrate, TCA cycle and oxidative phosphorylation, and from an energy budget

Temperature, energy metabolism, and adaptive divergence in two oyster subspecies.

PubMed

Li, Ao; Li, Li; Song, Kai; Wang, Wei; Zhang, Guofan

2017-08-01

Comparisons of related species that have diverse spatial distributions provide an efficient way to investigate adaptive evolution in face of increasing global warming. The oyster subjected to high environmental selections is a model species as sessile marine invertebrate. This study aimed to detect the adaptive divergence of energy metabolism in two oyster subspecies from the genus Crassostrea - C. gigas gigas and C. gigas angulata -which are broadly distributed along the northern and southern coasts of China, respectively. We examined the effects of acute thermal stress on energy metabolism in two oyster subspecies after being common gardened for one generation in identical conditions. Thermal responses were assessed by incorporating physiological, molecular, and genomic approaches. Southern oysters exhibited higher fluctuations in metabolic rate, activities of key energetic enzymes, and levels of thermally induced gene expression than northern oysters. For genes involved in energy metabolism, the former displayed higher basal levels of gene expression and a more pronounced downregulation of thermally induced expression, while the later exhibited lower basal levels and a less pronounced downregulation of gene expression. Contrary expression pattern was observed in oxidative stress gene. Besides, energy metabolic tradeoffs were detected in both subspecies. Furthermore, the genetic divergence of a nonsynonymous SNP ( SOD-132 ) and five synonymous SNPs in other genes was identified and validated in these two subspecies, which possibly affects downstream functions and explains the aforementioned phenotypic variations. Our study demonstrates that differentiations in energy metabolism underlie the plasticity of adaptive divergence in two oyster subspecies and suggest C. gigas angulata with moderate phenotypic plasticity has higher adaptive potential to cope with exacerbated global warming.

Hypothalamic carnitine metabolism integrates nutrient and hormonal feedback to regulate energy homeostasis.

PubMed

Stark, Romana; Reichenbach, Alex; Andrews, Zane B

2015-12-15

The maintenance of energy homeostasis requires the hypothalamic integration of nutrient feedback cues, such as glucose, fatty acids, amino acids, and metabolic hormones such as insulin, leptin and ghrelin. Although hypothalamic neurons are critical to maintain energy homeostasis research efforts have focused on feedback mechanisms in isolation, such as glucose alone, fatty acids alone or single hormones. However this seems rather too simplistic considering the range of nutrient and endocrine changes associated with different metabolic states, such as starvation (negative energy balance) or diet-induced obesity (positive energy balance). In order to understand how neurons integrate multiple nutrient or hormonal signals, we need to identify and examine potential intracellular convergence points or common molecular targets that have the ability to sense glucose, fatty acids, amino acids and hormones. In this review, we focus on the role of carnitine metabolism in neurons regulating energy homeostasis. Hypothalamic carnitine metabolism represents a novel means for neurons to facilitate and control both nutrient and hormonal feedback. In terms of nutrient regulation, carnitine metabolism regulates hypothalamic fatty acid sensing through the actions of CPT1 and has an underappreciated role in glucose sensing since carnitine metabolism also buffers mitochondrial matrix levels of acetyl-CoA, an allosteric inhibitor of pyruvate dehydrogenase and hence glucose metabolism. Studies also show that hypothalamic CPT1 activity also controls hormonal feedback. We hypothesis that hypothalamic carnitine metabolism represents a key molecular target that can concurrently integrate nutrient and hormonal information, which is critical to maintain energy homeostasis. We also suggest this is relevant to broader neuroendocrine research as it predicts that hormonal signaling in the brain varies depending on current nutrient status. Indeed, the metabolic action of ghrelin, leptin or insulin

Energy metabolism regulated by HDAC inhibitor attenuates cardiac injury in hemorrhagic rat model

PubMed Central

Kuai, Qiyuan; Wang, Chunyan; Wang, Yanbing; Li, Weijing; Zhang, Gongqing; Qiao, Zhixin; He, Min; Wang, Xuanlin; Wang, Yu; Jiang, Xingwei; Su, Lihua; He, Yuezhong; Ren, Suping; Yu, Qun

2016-01-01

A disturbance of energy metabolism reduces cardiac function in acute severe hemorrhagic patients. Alternatively, adequate energy supply reduces heart failure and increases survival. However, the approach to regulating energy metabolism conductive to vital organs is limited, and the underlying molecular mechanism remains unknown. This study assesses the ability of histone deacetylase inhibitors (HDACIs) to preserve cardiac energy metabolism during lethal hemorrhagic injury. In the lethally hemorrhagic rat and hypoxic myocardial cells, energy metabolism and heart function were well maintained following HDACI treatment, as evident by continuous ATP production with normal cardiac contraction. Valproic acid (VPA) regulated the energy metabolism of hemorrhagic heart by reducing lactate synthesis and protecting the mitochondrial ultrastructure and respiration, which were attributable to the inhibition of lactate dehydrogenase A activity and the increased myeloid cell leukemia-1 (mcl-1) gene expression, ultimately facilitating ATP production and consumption. MCL-1, the key target of VPA, mediated this cardioprotective effect under acute severe hemorrhage conditions. Our results suggest that HDACIs promote cardioprotection by improving energy metabolism during hemorrhagic injury and could therefore be an effective strategy to counteract this process in the clinical setting. PMID:27910887

In vivo analysis of NH4+ transport and central N-metabolism of Saccharomyces cerevisiae under aerobic N-limited conditions.

PubMed

Cueto-Rojas, H F; Maleki Seifar, R; Ten Pierick, A; van Helmond, W; Pieterse M, M; Heijnen, J J; Wahl, S A

2016-09-16

Ammonium is the most common N-source for yeast fermentations. Although, its transport and assimilation mechanisms are well documented, there have been only few attempts to measure the in vivo intracellular concentration of ammonium and assess its impact on gene expression. Using an isotope dilution mass spectrometry (IDMS)-based method we were able to measure the intracellular ammonium concentration in N-limited aerobic chemostat cultivations using three different N-sources (ammonium, urea and glutamate) at the same growth rate (0.05 h -1 ). The experimental results suggest that, at this growth rate, a similar concentration of intracellular ammonium, about 3.6 mmol NH 4 + /L IC , is required to supply the reactions in the central N-metabolism independent of the N-source. Based on the experimental results and different assumptions, the vacuolar and cytosolic ammonium concentrations were estimated. Furthermore, we identified a futile cycle caused by NH 3 leakage to the extracellular space, which can cost up to 30% of the ATP production of the cell under N-limited conditions, and a futile redox cycle between reactions Gdh1 and Gdh2. Finally, using shotgun proteomics with labeled reference-relative protein expression, differences between the various environmental conditions were identified and correlated with previously identified N-compound sensing mechanisms. In our work, we study central N-metabolism using quantitative approaches. First, intracellular ammonium was measured under different N-sources. The results suggest that Saccharomyces cerevisiae cells keep a constant NH 4 + concentration (around 3 mmol NH 4 + /L IC ), independent of the applied nitrogen source. We hypothesize that this amount of intracellular ammonium is required to obtain sufficient thermodynamic driving force.Furthermore, our calculations based on thermodynamic analysis of the transport mechanisms of ammonium suggest that ammonium is not equally distributed, indicating a high degree of

In Vivo Analysis of NH4+ Transport and Central Nitrogen Metabolism in Saccharomyces cerevisiae during Aerobic Nitrogen-Limited Growth

PubMed Central

Maleki Seifar, R.; ten Pierick, A.; van Helmond, W.; Pieterse, M. M.; Heijnen, J. J.

2016-01-01

ABSTRACT Ammonium is the most common N source for yeast fermentations. Although its transport and assimilation mechanisms are well documented, there have been only a few attempts to measure the in vivo intracellular concentration of ammonium and assess its impact on gene expression. Using an isotope dilution mass spectrometry (IDMS)-based method, we were able to measure the intracellular ammonium concentration in N-limited aerobic chemostat cultivations using three different N sources (ammonium, urea, and glutamate) at the same growth rate (0.05 h−1). The experimental results suggest that, at this growth rate, a similar concentration of intracellular (IC) ammonium, about 3.6 mmol NH4+/literIC, is required to supply the reactions in the central N metabolism, independent of the N source. Based on the experimental results and different assumptions, the vacuolar and cytosolic ammonium concentrations were estimated. Furthermore, we identified a futile cycle caused by NH3 leakage into the extracellular space, which can cost up to 30% of the ATP production of the cell under N-limited conditions, and a futile redox cycle between Gdh1 and Gdh2 reactions. Finally, using shotgun proteomics with protein expression determined relative to a labeled reference, differences between the various environmental conditions were identified and correlated with previously identified N compound-sensing mechanisms. IMPORTANCE In our work, we studied central N metabolism using quantitative approaches. First, intracellular ammonium was measured under different N sources. The results suggest that Saccharomyces cerevisiae cells maintain a constant NH4+ concentration (around 3 mmol NH4+/literIC), independent of the applied nitrogen source. We hypothesize that this amount of intracellular ammonium is required to obtain sufficient thermodynamic driving force. Furthermore, our calculations based on thermodynamic analysis of the transport mechanisms of ammonium suggest that ammonium is not equally

Oleanolic acid suppresses aerobic glycolysis in cancer cells by switching pyruvate kinase type M isoforms.

PubMed

Liu, Jia; Wu, Ning; Ma, Leina; Liu, Ming; Liu, Ge; Zhang, Yuyan; Lin, Xiukun

2014-01-01

Warburg effect, one of the hallmarks for cancer cells, is characterized by metabolic switch from mitochondrial oxidative phosphorylation to aerobic glycolysis. In recent years, increased expression level of pyruvate kinase M2 (PKM2) has been found to be the culprit of enhanced aerobic glycolysis in cancer cells. However, there is no agent inhibiting aerobic glycolysis by targeting PKM2. In this study, we found that Oleanolic acid (OA) induced a switch from PKM2 to PKM1, and consistently, abrogated Warburg effect in cancer cells. Suppression of aerobic glycolysis by OA is mediated by PKM2/PKM1 switch. Furthermore, mTOR signaling was found to be inactivated in OA-treated cancer cells, and mTOR inhibition is required for the effect of OA on PKM2/PKM1 switch. Decreased expression of c-Myc-dependent hnRNPA1 and hnRNPA1 was responsible for OA-induced switch between PKM isoforms. Collectively, we identified that OA is an antitumor compound that suppresses aerobic glycolysis in cancer cells and there is potential that PKM2 may be developed as an important target in aerobic glycolysis pathway for developing novel anticancer agents.

Bone: from a reservoir of minerals to a regulator of energy metabolism

PubMed Central

Confavreux, Cyrille B

2011-01-01

Besides locomotion, organ protection, and calcium–phosphorus homeostasis, the three classical functions of the skeleton, bone remodeling affects energy metabolism through uncarboxylated osteocalcin, a recently discovered hormone secreted by osteoblasts. This review traces how energy metabolism affects osteoblasts through the central control of bone mass involving leptin, serotoninergic neurons, the hypothalamus, and the sympathetic nervous system. Next, the role of osteocalcin (insulin secretion, insulin sensitivity, and pancreas β-cell proliferation) in the regulation of energy metabolism is described. Then, the connections between insulin signaling on osteoblasts and the release of uncarboxylated osteocalcin during osteoclast bone resorption through osteoprotegerin are reported. Finally, the understanding of this new bone endocrinology will provide some insights into bone, kidney, and energy metabolism in patients with chronic kidney disease. PMID:21346725

[Biochemical basis of the single theory of aging. Part II. The cell aerobic status, the hypoxia resistance and proliferation].

PubMed

Kirova, Iu I; Borodulin, V B

2009-01-01

Cells of an organism have different parameters of morphology, metabolism, isoenzyme composition, proliferation and respiration. These differences are derivatives of the cell aerobic status. The primary oxygen acceptors are the "macroscopic" cells (neurons, cardiocytes). In these obligatory aerobic cells oxygen is converted into metabolic water directly by the cytochrome oxidase activity. The secondary oxygen acceptors are the "microscopic" cells (other single-nucleus cells). In these facultative aerobic cells oxygen is converted into hydrogen peroxide. The intracellular labile peroxide pool of oxygen is formed by the oxidase, cytochrome P450, superoxide dismutase, and the mitochondrial cyan-resistance oxidase. The mitochondrial isoenzymes of catalase, glutation peroxidase, and thioredoxin reductase convert hydrogen peroxide into molecular oxygen and form high local oxygen concentration as the major factor for the cytochrome oxidase activity. The hypoxia resistance is increased by the growth of the functional activity of the peroxide-generative and peroxide-mobilizative enzyme systems.

Cutting Edge: Defective Aerobic Glycolysis Defines the Distinct Effector Function in Antigen-Activated CD8+ Recent Thymic Emigrants.

PubMed

Cunningham, Cody A; Bergsbaken, Tessa; Fink, Pamela J

2017-06-15

Recent thymic emigrants (RTEs) are the youngest peripheral T cells that have completed thymic selection and egress to the lymphoid periphery. RTEs are functionally distinct from their more mature but still naive T cell counterparts, because they exhibit dampened proliferation and reduced cytokine production upon activation. In this article, we show that, compared with more mature but still naive T cells, RTEs are impaired in their ability to perform aerobic glycolysis following activation. Impaired metabolism underlies the reduced IFN-γ production observed in activated RTEs. This failure to undergo Ag-induced aerobic glycolysis is caused by reduced mTORC1 activity and diminished Myc induction in RTEs. Critically, exogenous IL-2 restores Myc expression in RTEs, driving aerobic glycolysis and IFN-γ production to the level of mature T cells. These results reveal a previously unknown metabolic component to postthymic T cell maturation. Copyright © 2017 by The American Association of Immunologists, Inc.

A bioenergetics-kinetics coupled modeling study on subsurface microbial metabolism in a field biostimulation experiment

NASA Astrophysics Data System (ADS)

Jin, Q.; Zheng, Z.; Zhu, C.

2006-12-01

Microorganisms in nature conserve energy by catalyzing various geochemical reactions. To build a quantitative relationship between geochemical conditions and metabolic rates, we propose a bioenergetics-kinetics coupled modeling approach. This approach describes microbial community as a metabolic network, i.e., fermenting microbes degrade organic substrates while aerobic respirer, nitrate reducer, metal reducer, sulfate reducer, and methanogen consume the fermentation products. It quantifies the control of substrate availability and biological energy conservation on the metabolic rates using thermodynamically consistent rate laws. We applied this simulation approach to study the progress of microbial metabolism during a field biostimulation experiment conducted in Oak Ridge, Tennessee. In the experiment, ethanol was injected into a monitoring well and groundwater was sampled to monitor changes in the chemistry. With time, concentrations of ethanol and SO42- decreased while those of NH4+, Fe2+, and Mn2+ increased. The simulation results fitted well to the observation, indicating simultaneous ethanol degradation and terminal electron accepting processes. The rates of aerobic respiration and denitrification were mainly controlled by substrate concentrations while those of ethanol degradation, sulfate reduction, and methanogenesis were controlled dominantly by the energy availability. The simulation results suggested two different microbial growth statuses in the subsurface. For the functional groups with significant growth, variations with time in substrate concentrations demonstrated a typical S curve. For the groups without significant growth, initial decreases in substrate concentrations were linear with time. Injecting substrates followed by monitoring environmental chemistry therefore provides a convenient approach to characterize microbial growth in the subsurface where methods for direct observation are currently unavailable. This research was funded by the

Adaptation of Ribonucleic Acid Metabolism to Anoxia in Rice Embryos 1

PubMed Central

Aspart, Lorette; Got, Alain; Delseny, Michel; Mocquot, Bernard; Pradet, Alain

1983-01-01

Rice (Oryza sativa var. Cigalon) is a plant which can adapt to very stringent anoxic conditions. It has previously been shown that during the adaptation period the energy charge can be used as a marker for metabolic activity. We have studied RNA metabolism during this period and correlated it with changes in the energy charge. Uptake of labeled precursor, UTP-specific activity, and incorporation were measured. Immediately after transfer to anaerobic conditions, the UTP pool size is reduced and the overall rate of incorporation drops. During adaptation, the rate of incorporation increases and stabilizes at about half of its value in aerobic conditions. Analysis of RNA shows that rRNA and mRNA are synthesized and that the processing of ribosomal RNA precursor is altered. Polyribosomes are present throughout the adaptation period although their amount is reduced during the first hour of anoxia. Changes in poly(A) content were noticed, indicating that some mRNA are rapidly degraded. Taken together, the results show that the RNA metabolism can be modulated during adaptation to anoxia in a parallel manner with energy charge changes. PMID:16662943

Metabolic reprogramming in glioblastoma: the influence of cancer metabolism on epigenetics and unanswered questions

PubMed Central

Agnihotri, Sameer; Zadeh, Gelareh

2016-01-01

A defining hallmark of glioblastoma is altered tumor metabolism. The metabolic shift towards aerobic glycolysis with reprogramming of mitochondrial oxidative phosphorylation, regardless of oxygen availability, is a phenomenon known as the Warburg effect. In addition to the Warburg effect, glioblastoma tumor cells also utilize the tricarboxylic acid cycle/oxidative phosphorylation in a different capacity than normal tissue. Altered metabolic enzymes and their metabolites are oncogenic and not simply a product of tumor proliferation. Here we highlight the advantages of why tumor cells, including glioblastoma cells, require metabolic reprogramming and how tumor metabolism can converge on tumor epigenetics and unanswered questions in the field. PMID:26180081

Enhancement of Astroglial Aerobic Glycolysis by Extracellular Lactate-Mediated Increase in cAMP

PubMed Central

Vardjan, Nina; Chowdhury, Helena H.; Horvat, Anemari; Velebit, Jelena; Malnar, Maja; Muhič, Marko; Kreft, Marko; Krivec, Špela G.; Bobnar, Saša T.; Miš, Katarina; Pirkmajer, Sergej; Offermanns, Stefan; Henriksen, Gjermund; Storm-Mathisen, Jon; Bergersen, Linda H.; Zorec, Robert

2018-01-01

Besides being a neuronal fuel, L-lactate is also a signal in the brain. Whether extracellular L-lactate affects brain metabolism, in particular astrocytes, abundant neuroglial cells, which produce L-lactate in aerobic glycolysis, is unclear. Recent studies suggested that astrocytes express low levels of the L-lactate GPR81 receptor (EC50 ≈ 5 mM) that is in fat cells part of an autocrine loop, in which the Gi-protein mediates reduction of cytosolic cyclic adenosine monophosphate (cAMP). To study whether a similar signaling loop is present in astrocytes, affecting aerobic glycolysis, we measured the cytosolic levels of cAMP, D-glucose and L-lactate in single astrocytes using fluorescence resonance energy transfer (FRET)-based nanosensors. In contrast to the situation in fat cells, stimulation by extracellular L-lactate and the selective GPR81 agonists, 3-chloro-5-hydroxybenzoic acid (3Cl-5OH-BA) or 4-methyl-N-(5-(2-(4-methylpiperazin-1-yl)-2-oxoethyl)-4-(2-thienyl)-1,3-thiazol-2-yl)cyclohexanecarboxamide (Compound 2), like adrenergic stimulation, elevated intracellular cAMP and L-lactate in astrocytes, which was reduced by the inhibition of adenylate cyclase. Surprisingly, 3Cl-5OH-BA and Compound 2 increased cytosolic cAMP also in GPR81-knock out astrocytes, indicating that the effect is GPR81-independent and mediated by a novel, yet unidentified, excitatory L-lactate receptor-like mechanism in astrocytes that enhances aerobic glycolysis and L-lactate production via a positive feedback mechanism. PMID:29867342

Evolution of major metabolic innovations in the Precambrian

NASA Technical Reports Server (NTRS)

Barnabas, J.; Schwartz, R. M.; Dayhoff, M. O.

1982-01-01

A combination of information on the metabolic capabilities of prokaryotes with a composite phylogenetic tree depicting an overview of prokaryote evolution based on the sequences of bacterial ferredoxin, 2Fe-2S ferredoxin, 5S ribosomal RNA, and c-type cytochromes shows three zones of major metabolic innovation in the Precambrian. The middle of these, which reflects the genesis of oxygen-releasing photosynthesis and aerobic respiration, links metabolic innovations of the anaerobic stem on the one hand and, on the other, proliferation of aerobic bacteria and the symbiotic associations leading to the eukaryotes. Those pathways where information on the structure of the enzymes is known are especially considered. Halobacterium and Thermoplasma (archaebacteria) do not belong to a totally independent line on the basis of the composite tree but branch from the eukaryote cytoplasmic line.

Mitochondrial pyruvate carrier function determines cell stemness and metabolic reprogramming in cancer cells

PubMed Central

Li, Xiaoran; Kan, Quancheng; Fan, Zhirui; Li, Yaqing; Ji, Yasai; Zhao, Jing; Zhang, Mingzhi; Grigalavicius, Mantas; Berge, Viktor; Goscinski, Mariusz Adam; M. Nesland, Jahn; Suo, Zhenhe

2017-01-01

One of the remarkable features of cancer cells is aerobic glycolysis, a phenomenon known as the “Warburg Effect”, in which cells rely preferentially on glycolysis instead of oxidative phosphorylation (OXPHOS) as the main energy source even in the presence of high oxygen tension. Cells with dysfunctional mitochondria are unable to generate sufficient ATP from mitochondrial OXPHOS, and then are forced to rely on glycolysis for ATP generation. Here we report our results in a prostate cancer cell line in which the mitochondrial pyruvate carrier 1 (MPC1) gene was knockout. It was discovered that the MPC1 gene knockout cells revealed a metabolism reprogramming to aerobic glycolysis with reduced ATP production, and the cells became more migratory and resistant to both chemotherapy and radiotherapy. In addition, the MPC1 knockout cells expressed significantly higher levels of the stemness markers Nanog, Hif1α, Notch1, CD44 and ALDH. To further verify the correlation of MPC gene function and cell stemness/metabolic reprogramming, MPC inhibitor UK5099 was applied in two ovarian cancer cell lines and similar results were obtained. Taken together, our results reveal that functional MPC may determine the fate of metabolic program and the stemness status of cancer cells in vitro. PMID:28624784

Energy metabolism in neuroblastoma and Wilms tumor

PubMed Central

Aminzadeh, Sepideh; Vidali, Silvia; Sperl, Wolfgang; Feichtinger, René G.

2015-01-01

To support high proliferation, the majority of cancer cells undergo fundamental metabolic changes such as increasing their glucose uptake and shifting to glycolysis for ATP production at the expense of far more efficient mitochondrial energy production by oxidative phosphorylation (OXPHOS), which at first glance is a paradox. This phenomenon is known as the Warburg effect. However, enhanced glycolysis is necessary to provide building blocks for anabolic growth. Apart from the generation of ATP, intermediates of glycolysis serve as precursors for a variety of biosynthetic pathways essential for cell proliferation. In the last 10-15 years the field of tumor metabolism has experienced an enormous boom in interest. It is now well established that tumor suppressor genes and oncogenes often play a central role in the regulation of cellular metabolism. Therefore, they significantly contribute to the manifestation of the Warburg effect. While much attention has focused on adult solid tumors, so far there has been comparatively little effort directed at elucidation of the mechanism responsible for the Warburg effect in childhood cancers. In this review we focus on metabolic pathways in neuroblastoma (NB) and Wilms tumor (WT), the two most frequent solid tumors in children. Both tumor types show alterations of the OXPHOS system and glycolytic features. Chromosomal alterations and activation of oncogenes like MYC or inactivation of tumor suppressor genes like TP53 can in part explain the changes of energy metabolism in these cancers. The strict dependence of cancer cells on glucose metabolism is a fairly common feature among otherwise biologically diverse types of cancer. Therefore, inhibition of glycolysis or starvation of cancer cells through glucose deprivation via a high-fat low-carbohydrate diet may be a promising avenue for future adjuvant therapeutic strategies. PMID:26835356

Energy metabolism, body composition, and urea generation rate in hemodialysis patients.

PubMed

Sridharan, Sivakumar; Vilar, Enric; Berdeprado, Jocelyn; Farrington, Ken

2013-10-01

Hemodialysis (HD) adequacy is currently assessed using normalized urea clearance (Kt/V), although scaling based on Watson volume (V) may disadvantage women and men with low body weight. Alternative scaling factors such as resting energy expenditure and high metabolic rate organ mass have been suggested. The relationship between such factors and uremic toxin generation has not been established. We aimed to study the relationship between body size, energy metabolism, and urea generation rate. A cross-sectional cohort of 166 HD patients was studied. Anthropometric measurements were carried on all. Resting energy expenditure was measured by indirect calorimetry, fat-free mass by bio-impedance and total energy expenditure by combining resting energy expenditure with a questionnaire-derived physical activity data. High metabolic rate organ mass was calculated using a published equation and urea generation rate using formal urea kinetic modeling. Metabolic factors including resting energy expenditure, total energy expenditure and fat-free mass correlated better with urea generation rate than did Watson volume. Total energy expenditure and fat-free mass (but not Watson Volume) were independent predictors of urea generation rate, the model explaining 42% of its variation. Small women (energy expenditure correlated significantly with urea generation rate. Energy metabolism, body composition and physical activity play important roles in small solute uremic toxin generation in HD patients and hence may impact on minimum dialysis requirements. Small women generate relatively more small solute toxins than other groups and thus may have a higher relative need for dialysis. © 2013 The Authors. Hemodialysis

Does exercise training affect resting metabolic rate in adolescents with obesity?

PubMed

Alberga, Angela S; Prud'homme, Denis; Sigal, Ronald J; Goldfield, Gary S; Hadjiyannakis, Stasia; Gougeon, Réjeanne; Phillips, Penny; Malcolm, Janine; Wells, George A; Doucette, Steve; Ma, Jinhui; Kenny, Glen P

2017-01-01

We evaluated the hypothesis that resistance exercise training performed alone or in combination with aerobic exercise training would increase resting metabolic rate (RMR) relative to aerobic-only and nonexercising control groups. Postpubertal adolescents (N = 304) aged 14-18 years with obesity (body mass index (BMI) ≥ 95th percentile) or overweight (BMI ≥ 85th percentile + additional diabetes risk factor(s)) were randomized to 4 groups for 22 weeks: Aerobic exercise training, Resistance exercise training, Combined aerobic and resistance exercise training, or Control. All participants received dietary counselling targeting a daily energy deficit of 250 kcal. RMR was measured by indirect calorimetry and body composition by magnetic resonance imaging. There was no significant change in RMR in any group, in spite of significant within-group increases in fat-free mass in the Aerobic, Resistance, and Combined exercise training groups. RMR at baseline and 6 months were Aerobic: 1972 ± 38 and 1990 ± 41; Resistance: 2024 ± 37 and 1992 ± 41; Combined: 2023 ± 38 and 1995 ± 38; Control: 2075 ± 38 and 2073 ± 39 kcal/day (p > 0.05). There were no between-group differences in RMR after adjustment for total body weight or fat-free mass between groups over time. Per-protocol analyses including only participants with ≥70% adherence, and analyses stratified by sex, also showed no within- or between-group differences in RMR. In conclusion, despite an increase in fat-free mass in all exercise groups, 6 months of aerobic, resistance, or combined training with modest dietary restriction did not increase RMR compared with diet only in adolescents with obesity.

Aerobic scope measurements of fishes in an era of climate change: respirometry, relevance and recommendations.

PubMed

Clark, Timothy D; Sandblom, Erik; Jutfelt, Fredrik

2013-08-01

Measurements of aerobic scope [the difference between minimum and maximum oxygen consumption rate ( and , respectively)] are increasing in prevalence as a tool to address questions relating to fish ecology and the effects of climate change. However, there are underlying issues regarding the array of methods used to measure aerobic scope across studies and species. In an attempt to enhance quality control before the diversity of issues becomes too great to remedy, this paper outlines common techniques and pitfalls associated with measurements of , and aerobic scope across species and under different experimental conditions. Additionally, we provide a brief critique of the oxygen- and capacity-limited thermal tolerance (OCLTT) hypothesis, a concept that is intricately dependent on aerobic scope measurements and is spreading wildly throughout the literature despite little evidence for its general applicability. It is the intention of this paper to encourage transparency and accuracy in future studies that measure the aerobic metabolism of fishes, and to highlight the fundamental issues with assuming broad relevance of the OCLTT hypothesis.

Settling properties of aerobic granular sludge (AGS) and aerobic granular sludge molasses (AGSM)

NASA Astrophysics Data System (ADS)

Mat Saad, Azlina; Aini Dahalan, Farrah; Ibrahim, Naimah; Yasina Yusuf, Sara; Aqlima Ahmad, Siti; Khalil, Khalilah Abdul

2018-03-01

Aerobic granulation technology is applied to treat domestic and industrial wastewater. The Aerobic granular sludge (AGS) cultivated has strong properties that appears to be denser and compact in physiological structure compared to the conventional activated sludge. It offers rapid settling for solid:liquid separation in wastewater treatment. Aerobic granules were developed using sequencing batch reactor (SBR) with intermittent aerobic - anaerobic mode with 8 cycles in 24 hr. This study examined the settling velocity performance of cultivated aerobic granular sludge (AGS) and aerobic granular sludge molasses (AGSM). The elemental composition in both AGS and AGSM were determined using X-ray fluorescence (XRF). The results showed that AGSM has higher settling velocity 30.5 m/h compared to AGS.

Adaptation to Aerobic Environment of Lactobacillus johnsonii/gasseri Strains

PubMed Central

Maresca, Diamante; Zotta, Teresa; Mauriello, Gianluigi

2018-01-01

Oxygen is considered one of the main factors affecting probiotic bacteria survival due to the induction of oxidative damages caused by the action of reactive oxygen species (ROS). It has been shown that oxidative stress resistance in lactic acid bacteria is strongly dependent on the type of cell metabolism. Shift from fermentative to respiratory metabolism (through the addition of heme and menaquinone and in presence of oxygen) was associated to increase in biomass, long-term survival, and production of antioxidant enzymes. The aim of this work was to investigate the effect of aerobic (presence of oxygen) and respiratory (presence of oxygen, heme, and menaquinone) cultivation on the growth kinetic, catalase production, oxygen uptake, and oxidative stress response of Lactobacillus johnsonii/gasseri strains previously isolated from infant feces. Seven strains showed to consume oxygen under aerobic and respiratory conditions. The strain AL5 showed a catalase activity in both growth conditions, while AL3 showed this activity only in respiratory condition. Respiratory condition improved their tolerance to oxidative compounds (hydrogen peroxide and ROS generators) and further they showed promising probiotic features. The exploration of respiratory competent phenotypes with probiotic features may be extremely useful for the development of competitive starter or probiotic cultures. PMID:29479342

Adaptation to Aerobic Environment of Lactobacillus johnsonii/gasseri Strains.

PubMed

Maresca, Diamante; Zotta, Teresa; Mauriello, Gianluigi

2018-01-01

Oxygen is considered one of the main factors affecting probiotic bacteria survival due to the induction of oxidative damages caused by the action of reactive oxygen species (ROS). It has been shown that oxidative stress resistance in lactic acid bacteria is strongly dependent on the type of cell metabolism. Shift from fermentative to respiratory metabolism (through the addition of heme and menaquinone and in presence of oxygen) was associated to increase in biomass, long-term survival, and production of antioxidant enzymes. The aim of this work was to investigate the effect of aerobic (presence of oxygen) and respiratory (presence of oxygen, heme, and menaquinone) cultivation on the growth kinetic, catalase production, oxygen uptake, and oxidative stress response of Lactobacillus johnsonii/gasseri strains previously isolated from infant feces. Seven strains showed to consume oxygen under aerobic and respiratory conditions. The strain AL5 showed a catalase activity in both growth conditions, while AL3 showed this activity only in respiratory condition. Respiratory condition improved their tolerance to oxidative compounds (hydrogen peroxide and ROS generators) and further they showed promising probiotic features. The exploration of respiratory competent phenotypes with probiotic features may be extremely useful for the development of competitive starter or probiotic cultures.

Ontogeny of hepatic energy metabolism genes in mice as revealed by RNA-sequencing.

PubMed

Renaud, Helen J; Cui, Yue Julia; Lu, Hong; Zhong, Xiao-bo; Klaassen, Curtis D

2014-01-01

The liver plays a central role in metabolic homeostasis by coordinating synthesis, storage, breakdown, and redistribution of nutrients. Hepatic energy metabolism is dynamically regulated throughout different life stages due to different demands for energy during growth and development. However, changes in gene expression patterns throughout ontogeny for factors important in hepatic energy metabolism are not well understood. We performed detailed transcript analysis of energy metabolism genes during various stages of liver development in mice. Livers from male C57BL/6J mice were collected at twelve ages, including perinatal and postnatal time points (n = 3/age). The mRNA was quantified by RNA-Sequencing, with transcript abundance estimated by Cufflinks. One thousand sixty energy metabolism genes were examined; 794 were above detection, of which 627 were significantly changed during at least one developmental age compared to adult liver. Two-way hierarchical clustering revealed three major clusters dependent on age: GD17.5-Day 5 (perinatal-enriched), Day 10-Day 20 (pre-weaning-enriched), and Day 25-Day 60 (adolescence/adulthood-enriched). Clustering analysis of cumulative mRNA expression values for individual pathways of energy metabolism revealed three patterns of enrichment: glycolysis, ketogenesis, and glycogenesis were all perinatally-enriched; glycogenolysis was the only pathway enriched during pre-weaning ages; whereas lipid droplet metabolism, cholesterol and bile acid metabolism, gluconeogenesis, and lipid metabolism were all enriched in adolescence/adulthood. This study reveals novel findings such as the divergent expression of the fatty acid β-oxidation enzymes Acyl-CoA oxidase 1 and Carnitine palmitoyltransferase 1a, indicating a switch from mitochondrial to peroxisomal β-oxidation after weaning; as well as the dynamic ontogeny of genes implicated in obesity such as Stearoyl-CoA desaturase 1 and Elongation of very long chain fatty acids-like 3. These

Long-lived mitochondrial (Mit) mutants of Caenorhabditis elegans utilize a novel metabolism.

PubMed

Butler, Jeffrey A; Ventura, Natascia; Johnson, Thomas E; Rea, Shane L

2010-12-01

The Caenorhabditis elegans mitochondrial (Mit) mutants have disrupted mitochondrial electron transport chain (ETC) functionality, yet, surprisingly, they are long lived. We have previously proposed that Mit mutants supplement their energy needs by exploiting alternate energy production pathways normally used by wild-type animals only when exposed to hypoxic conditions. We have also proposed that longevity in the Mit mutants arises as a property of their new metabolic state. If longevity does arise as a function of metabolic state, we would expect to find a common metabolic signature among these animals. To test these predictions, we established a novel approach monitoring the C. elegans exometabolism as a surrogate marker for internal metabolic events. Using HPLC-ultraviolet-based metabolomics and multivariate analyses, we show that long-lived clk-1(qm30) and isp-1(qm150) Mit mutants have a common metabolic profile that is distinct from that of aerobically cultured wild-type animals and, unexpectedly, wild-type animals cultured under severe oxygen deprivation. Moreover, we show that 2 short-lived mitochondrial ETC mutants, mev-1(kn1) and ucr-2.3(pk732), also share a common metabolic signature that is unique. We show that removal of soluble fumarate reductase unexpectedly increases health span in several genetically defined Mit mutants, identifying at least 1 alternate energy production pathway, malate dismutation, that is operative in these animals. Our study suggests long-lived, genetically specified Mit mutants employ a novel metabolism and that life span may well arise as a function of metabolic state.

Grey water treatment in a series anaerobic--aerobic system for irrigation.

PubMed

Abu Ghunmi, Lina; Zeeman, Grietje; Fayyad, Manar; van Lier, Jules B

2010-01-01

This study aims at treatment of grey water for irrigation, focusing on a treatment technology that is robust, simple to operate and with minimum energy consumption. The result is an optimized system consisting of an anaerobic unit operated in upflow mode, with a 1 day operational cycle, a constant effluent flow rate and varying liquid volume. Subsequent aerobic step is equipped with mechanical aeration and the system is insulated for sustaining winter conditions. The COD removal achieved by the anaerobic and aerobic units in summer and winter are 45%, 39% and 53%, 64%, respectively. Sludge in the anaerobic and aerobic reactor has a concentration of 168 and 8 mg VSL(-1), respectively. Stability of sludge in the anaerobic and aerobic reactors is 80% and 93%, respectively, based on COD. Aerobic effluent quality, except for pathogens, agrees with the proposed irrigation water quality guidelines for reclaimed water in Jordan.

Loss of Brain Aerobic Glycolysis in Normal Human Aging.

PubMed

Goyal, Manu S; Vlassenko, Andrei G; Blazey, Tyler M; Su, Yi; Couture, Lars E; Durbin, Tony J; Bateman, Randall J; Benzinger, Tammie L-S; Morris, John C; Raichle, Marcus E

2017-08-01

The normal aging human brain experiences global decreases in metabolism, but whether this affects the topography of brain metabolism is unknown. Here we describe PET-based measurements of brain glucose uptake, oxygen utilization, and blood flow in cognitively normal adults from 20 to 82 years of age. Age-related decreases in brain glucose uptake exceed that of oxygen use, resulting in loss of brain aerobic glycolysis (AG). Whereas the topographies of total brain glucose uptake, oxygen utilization, and blood flow remain largely stable with age, brain AG topography changes significantly. Brain regions with high AG in young adults show the greatest change, as do regions with prolonged developmental transcriptional features (i.e., neoteny). The normal aging human brain thus undergoes characteristic metabolic changes, largely driven by global loss and topographic changes in brain AG. Copyright © 2017 Elsevier Inc. All rights reserved.

[Assessment of energy metabolism and nutritional supply in children with mechanical ventilation].

PubMed

Ji, Jian; Qian, Suyun; Yan, Jie

2016-01-01

To determine the resting energy expenditure on mechanical ventilation in pediatric intensive care unit (PICU) by indirect calorimetry, and analyze the distribution of metabolic states. The nutrition supply was assessed according to the resting energy expenditure. An observational study which was held in PICU of Beijing Children's Hospital from November 2013 to April 2014. Critically ill children with mechanical ventilation were enrolled in this study. The inclusion criteria included the following: (1) pediatric critical illness score < 90, or meet the United States PICU admission criteria; (2) age > 29 days, < 18 years old; (3) time of mechanical ventilation > 24 hours; (4) volume of mechanical ventilation > 60 ml. Resting energy expenditure was determined by US Med Graphic Company CCM/D energy metabolism test system. Predictive resting energy expenditure was calculated for each subject with age-appropriate equation (Schofield-HTWT). According to the actual energy intake records and required energy intake (10% higher than the measured value) to define the nutritional status. The selected subjects were grouped according to gender, age, types of disease and nutritional status, and compared the metabolic status and nutritional supply of different groups. Sixty-eight children were enrolled in this study, 46 were boys and 22 were girls, including 25 cases of pneumonia with respiratory failure, 23 cases of central nervous system diseases complicated with respiratory failure and 20 cases of postoperative tracheal intubation. The ratio of boys and girls was 2:1. The results showed 36 patients in a low metabolic state, accounting for 53%, 23 patients in a high metabolic state, accounting for 34% and 9 patients (13%) in the metabolism of the normal state. In the male children, 12 cases (26%) were in the high metabolism and 26 cases (57%) were in the low metabolism, and 8 cases (17%) were in the normal metabolism. In the female children, 11 cases (50%) were classified into

Evolution of energy metabolism and its compartmentation in Kinetoplastida

PubMed Central

Hannaert, Véronique; Bringaud, Frédéric; Opperdoes, Fred R; Michels, Paul AM

2003-01-01

Kinetoplastida are protozoan organisms that probably diverged early in evolution from other eukaryotes. They are characterized by a number of unique features with respect to their energy and carbohydrate metabolism. These organisms possess peculiar peroxisomes, called glycosomes, which play a central role in this metabolism; the organelles harbour enzymes of several catabolic and anabolic routes, including major parts of the glycolytic and pentosephosphate pathways. The kinetoplastid mitochondrion is also unusual with regard to both its structural and functional properties. In this review, we describe the unique compartmentation of metabolism in Kinetoplastida and the metabolic properties resulting from this compartmentation. We discuss the evidence for our recently proposed hypothesis that a common ancestor of Kinetoplastida and Euglenida acquired a photosynthetic alga as an endosymbiont, contrary to the earlier notion that this event occurred at a later stage of evolution, in the Euglenida lineage alone. The endosymbiont was subsequently lost from the kinetoplastid lineage but, during that process, some of its pathways of energy and carbohydrate metabolism were sequestered in the kinetoplastid peroxisomes, which consequently became glycosomes. The evolution of the kinetoplastid glycosomes and the possible selective advantages of these organelles for Kinetoplastida are discussed. We propose that the possession of glycosomes provided metabolic flexibility that has been important for the organisms to adapt easily to changing environmental conditions. It is likely that metabolic flexibility has been an important selective advantage for many kinetoplastid species during their evolution into the highly successful parasites today found in many divergent taxonomic groups. Also addressed is the evolution of the kinetoplastid mitochondrion, from a supposedly pluripotent organelle, attributed to a single endosymbiotic event that resulted in all mitochondria and

Thermodynamics of the living organisms. Allometric relationship between the total metabolic energy, chemical energy and body temperature in mammals

NASA Astrophysics Data System (ADS)

Atanasov, Atanas Todorov

2017-11-01

The study present relationship between the total metabolic energy (ETME(c), J) derived as a function of body chemical energy (Gchem, J) and absolute temperature (Tb, K) in mammals: ETME(c) =Gchem (Tb/Tn). In formula the temperature Tn =2.73K appears normalization temperature. The calculated total metabolic energy ETME(c) differs negligible from the total metabolic energy ETME(J), received as a product between the basal metabolic rate (Pm, J/s) and the lifespan (Tls, s) of mammals: ETME = Pm×Tls. The physical nature and biological mean of the normalization temperature (Tn, K) is unclear. It is made the hypothesis that the kTn energy (where k= 1.3806×10-23 J/K -Boltzmann constant) presents energy of excitation states (modes) in biomolecules and body structures that could be in equilibrium with chemical energy accumulated in body. This means that the accumulated chemical energy allows trough all body molecules and structures to propagate excitations states with kTn energy with wavelength in the rage of width of biological membranes. The accumulated in biomolecules chemical energy maintains spread of the excited states through biomolecules without loss of energy.

Rh2E2, a novel metabolic suppressor, specifically inhibits energy-based metabolism of tumor cells

PubMed Central

Bai, Li-Ping; Jiang, Zhi-Hong; Guo, Yue; Kong, Ah-Ng Tony; Wang, Rui; Kam, Richard Kin Ting; Law, Betty Yuen Kwan; Hsiao, Wendy Wen Luen; Chan, Ka Man; Wang, Jingrong; Chan, Rick Wai Kit; Guo, Jianru; Zhang, Wei; Yen, Feng Gen; Zhou, Hua; Leung, Elaine Lai Han; Yu, Zhiling; Liu, Liang

2016-01-01

Energy metabolism in cancer cells is often increased to meet their higher proliferative rate and biosynthesis demands. Suppressing cancer cell metabolism using agents like metformin has become an attractive strategy for treating cancer patients. We showed that a novel ginsenoside derivative, Rh2E2, is as effective as aspirin in preventing the development of AOM/DSS-induced colorectal cancer and suppresses tumor growth and metastasis in a LLC-1 xenograft. A sub-chronic and acute toxicity LD50 test of Rh2E2 showed no harmful reactions at the maximum oral dosage of 5000 mg/kg body weight in mice. Proteomic profiling revealed that Rh2E2 specifically inhibited ATP production in cancer cells via down-regulation of metabolic enzymes involving glycolysis, fatty acid β-oxidation and the tricarboxylic acid cycle, leading to specific cytotoxicity and S-phase cell cycle arrest in cancer cells. Those findings suggest that Rh2E2 possesses a novel and safe anti-metabolic agent for cancer patients by specific reduction of energy-based metabolism in cancer cells. PMID:26799418

Examining physiotherapist use of structured aerobic exercise testing to decrease barriers to aerobic exercise.

PubMed

Foster B Sc, Evan; Fraser, Julia E; Inness PhD, Elizabeth L; Munce, Sarah; Biasin, Louis; Poon, Vivien; Bayley, Mark

2018-04-03

To determine the frequency of physiotherapist-administered aerobic exercise testing/training, the proportion of physiotherapists who administer this testing/training, and the barriers that currently exist across different practice environments. A secondary objective is to identify the learning needs of physiotherapists for the development of an education curriculum in aerobic exercise testing and training with electrocardiograph (ECG) administration and interpretation. National, cross-sectional survey. Registered physiotherapists practicing in Canada. Out of 137 participants, most (75%) physiotherapists prescribed aerobic exercise on a regular basis (weekly); however, 65% had never conducted an aerobic exercise test. There were no significant differences in frequency of aerobic exercise testing across different practice environments or across years of physiotherapy experience. Physiotherapists perceived the main barriers to aerobic exercise testing as being a lack of equipment/space (78%), time (65%), and knowledge (56%). Although most (82%) were uncomfortable administering 12-lead ECG-monitored aerobic exercise tests, 60% stated they would be interested in learning more about ECG interpretation. This study found that physiotherapists are regularly implementing aerobic exercise. This exercise was infrequently guided by formal aerobic exercise testing, which could increase access to safe and effective exercise within the optimal aerobic training zone. As well, this could facilitate training in patients with cardiovascular diagnoses that require additional testing for medical clearance. Increased ECG training and access to equipment for physiotherapists may augment pre-screening aerobic exercise testing. This training should include learning the key arrhythmias for aerobic exercise test termination as defined by the American College of Sports Medicine.

Mechanisms of aerobic performance impairment with heat stress and dehydration.

PubMed

Cheuvront, Samuel N; Kenefick, Robert W; Montain, Scott J; Sawka, Michael N

2010-12-01

Environmental heat stress can challenge the limits of human cardiovascular and temperature regulation, body fluid balance, and thus aerobic performance. This minireview proposes that the cardiovascular adjustments accompanying high skin temperatures (T(sk)), alone or in combination with high core body temperatures (T(c)), provide a primary explanation for impaired aerobic exercise performance in warm-hot environments. The independent (T(sk)) and combined (T(sk) + T(c)) effects of hyperthermia reduce maximal oxygen uptake (Vo(2max)), which leads to higher relative exercise intensity and an exponential decline in aerobic performance at any given exercise workload. Greater relative exercise intensity increases cardiovascular strain, which is a prominent mediator of rated perceived exertion. As a consequence, incremental or constant-rate exercise is more difficult to sustain (earlier fatigue) or requires a slowing of self-paced exercise to achieve a similar sensation of effort. It is proposed that high T(sk) and T(c) impair aerobic performance in tandem primarily through elevated cardiovascular strain, rather than a deterioration in central nervous system (CNS) function or skeletal muscle metabolism. Evaporative sweating is the principal means of heat loss in warm-hot environments where sweat losses frequently exceed fluid intakes. When dehydration exceeds 3% of total body water (2% of body mass) then aerobic performance is consistently impaired independent and additive to heat stress. Dehydration augments hyperthermia and plasma volume reductions, which combine to accentuate cardiovascular strain and reduce Vo(2max). Importantly, the negative performance consequences of dehydration worsen as T(sk) increases.

Determination of reaction rates and activation energy in aerobic composting processes for yard waste.

PubMed

Uma, R N; Manjula, G; Meenambal, T

2007-04-01

The reaction rates and activation energy in aerobic composting processes for yard waste were determined using specifically designed reactors. Different mixture ratios were fixed before the commencement of the process. The C/N ratio was found to be optimum for a mixture ratio of 1:6 containing one part of coir pith to six parts of other waste which included yard waste, yeast sludge, poultry yard waste and decomposing culture (Pleurotosis). The path of stabilization of the wastes was continuously monitored by observing various parameters such as temperature, pH, Electrical Conductivity, C.O.D, VS at regular time intervals. Kinetic analysis was done to determine the reaction rates and activation energy for the optimum mixture ratio under forced aeration condition. The results of the analysis clearly indicated that the temperature dependence of the reaction rates followed the Arrhenius equation. The temperature coefficients were also determined. The degradation of the organic fraction of the yard waste could be predicted using first order reaction model.

Anaerobic energy metabolism in unicellular photosynthetic eukaryotes.

PubMed

Atteia, Ariane; van Lis, Robert; Tielens, Aloysius G M; Martin, William F

2013-02-01

Anaerobic metabolic pathways allow unicellular organisms to tolerate or colonize anoxic environments. Over the past ten years, genome sequencing projects have brought a new light on the extent of anaerobic metabolism in eukaryotes. A surprising development has been that free-living unicellular algae capable of photoautotrophic lifestyle are, in terms of their enzymatic repertoire, among the best equipped eukaryotes known when it comes to anaerobic energy metabolism. Some of these algae are marine organisms, common in the oceans, others are more typically soil inhabitants. All these species are important from the ecological (O(2)/CO(2) budget), biotechnological, and evolutionary perspectives. In the unicellular algae surveyed here, mixed-acid type fermentations are widespread while anaerobic respiration, which is more typical of eukaryotic heterotrophs, appears to be rare. The presence of a core anaerobic metabolism among the algae provides insights into its evolutionary origin, which traces to the eukaryote common ancestor. The predicted fermentative enzymes often exhibit an amino acid extension at the N-terminus, suggesting that these proteins might be compartmentalized in the cell, likely in the chloroplast or the mitochondrion. The green algae Chlamydomonas reinhardtii and Chlorella NC64 have the most extended set of fermentative enzymes reported so far. Among the eukaryotes with secondary plastids, the diatom Thalassiosira pseudonana has the most pronounced anaerobic capabilities as yet. From the standpoints of genomic, transcriptomic, and biochemical studies, anaerobic energy metabolism in C. reinhardtii remains the best characterized among photosynthetic protists. This article is part of a Special Issue entitled: The evolutionary aspects of bioenergetic systems. Copyright © 2012 Elsevier B.V. All rights reserved.

Aerobic interval exercise improves parameters of nonalcoholic fatty liver disease (NAFLD) and other alterations of metabolic syndrome in obese Zucker rats.

PubMed

Kapravelou, Garyfallia; Martínez, Rosario; Andrade, Ana M; Nebot, Elena; Camiletti-Moirón, Daniel; Aparicio, Virginia A; Lopez-Jurado, Maria; Aranda, Pilar; Arrebola, Francisco; Fernandez-Segura, Eduardo; Bermano, Giovanna; Goua, Marie; Galisteo, Milagros; Porres, Jesus M

2015-12-01

Metabolic syndrome (MS) is a group of metabolic alterations that increase the susceptibility to cardiovascular disease and type 2 diabetes. Nonalcoholic fatty liver disease has been described as the liver manifestation of MS. We aimed to test the beneficial effects of an aerobic interval training (AIT) protocol on different biochemical, microscopic, and functional liver alterations related to the MS in the experimental model of obese Zucker rat. Two groups of lean and obese animals (6 weeks old) followed a protocol of AIT (4 min at 65%-80% of maximal oxygen uptake, followed by 3 min at 50%-65% of maximal oxygen uptake for 45-60 min, 5 days/week, 8 weeks of experimental period), whereas 2 control groups remained sedentary. Obese rats had higher food intake and body weight (P < 0.0001) and suffered significant alterations in plasma lipid profile, area under the curve after oral glucose overload (P < 0.0001), liver histology and functionality, and antioxidant status. The AIT protocol reduced the severity of alterations related to glucose and lipid metabolism and increased the liver protein expression of PPARγ, as well as the gene expression of glutathione peroxidase 4 (P < 0.001). The training protocol also showed significant effects on the activity of hepatic antioxidant enzymes, although this action was greatly influenced by rat phenotype. The present data suggest that AIT protocol is a feasible strategy to improve some of the plasma and liver alterations featured by the MS.

Circadian control of p75 neurotrophin receptor leads to alternate activation of Nrf2 and c-Rel to reset energy metabolism in astrocytes via brain-derived neurotrophic factor.

PubMed

Ishii, Tetsuro; Warabi, Eiji; Mann, Giovanni E

2018-05-01

Circadian clock genes regulate energy metabolism partly through neurotrophins in the body. The low affinity neurotrophin receptor p75 NTR is a clock component directly regulated by the transcriptional factor Clock:Bmal1 complex. Brain-derived neurotrophic factor (BDNF) is expressed in the brain and plays a key role in coordinating metabolic interactions between neurons and astrocytes. BDNF transduces signals through TrkB and p75 NTR receptors. This review highlights a novel molecular mechanism by which BDNF via circadian control of p75 NTR leads to daily resetting of glucose and glycogen metabolism in brain astrocytes to accommodate their functional interaction with neurons. Astrocytes store glycogen as an energy reservoir to provide active neurons with the glycolytic metabolite lactate. Astrocytes predominantly express the truncated receptor TrkB.T1 which lacks an intracellular receptor tyrosine kinase domain. TrkB.T1 retains the capacity to regulate cell morphology through regulation of Rho GTPases. In contrast, p75 NTR mediates generation of the bioactive lipid ceramide upon stimulation with BDNF and inhibits PKA activation. As ceramide directly activates PKCζ, we discuss the importance of the TrkB.T1-p75 NTR -ceramide-PKCζ signaling axis in the stimulation of glycogen and lipid synthesis and activation of RhoA. Ceramide-PKCζ-casein kinase 2 signaling activates Nrf2 to support oxidative phosphorylation via upregulation of antioxidant enzymes. In the absence of p75 NTR , TrkB.T1 functionally interacts with adenosine A 2A R and dopamine D1R receptors to enhance cAMP-PKA signaling and activate Rac1 and NF-κB c-Rel, favoring glycogen hydrolysis, gluconeogenesis and aerobic glycolysis. Thus, diurnal changes in p75 NTR levels in astrocytes resets energy metabolism via BDNF to accommodate their metabolic interaction with neurons. Copyright © 2018 Elsevier Inc. All rights reserved.

Tennis Play Intensity Distribution and Relation with Aerobic Fitness in Competitive Players

PubMed Central

Baiget, Ernest; Fernández-Fernández, Jaime; Iglesias, Xavier; Rodríguez, Ferran A.

2015-01-01

The aims of this study were (i) to describe the relative intensity of simulated tennis play based on the cumulative time spent in three metabolic intensity zones, and (ii) to determine the relationships between this play intensity distribution and the aerobic fitness of a group of competitive players. 20 male players of advanced to elite level (ITN) performed an incremental on-court specific endurance tennis test to exhaustion to determine maximal oxygen uptake (VO2max) and the first and second ventilatory thresholds (VT1, VT2). Ventilatory and gas exchange parameters were monitored using a telemetric portable gas analyser (K4 b2, Cosmed, Rome, Italy). Two weeks later the participants played a simulated tennis set against an opponent of similar level. Intensity zones (1: low, 2: moderate, and 3: high) were delimited by the individual VO2 values corresponding to VT1 and VT2, and expressed as percentage of maximum VO2 and heart rate. When expressed relative to VO2max, percentage of playing time in zone 1 (77 ± 25%) was significantly higher (p < 0.001) than in zone 2 (20 ± 21%) and zone 3 (3 ± 5%). Moderate to high positive correlations were found between VT1, VT2 and VO2max, and the percentage of playing time spent in zone 1 (r = 0.68–0.75), as well as low to high inverse correlations between the metabolic variables and the percentage of time spent in zone 2 and 3 (r = -0.49–0.75). Players with better aerobic fitness play at relatively lower intensities. We conclude that players spent more than 75% of the time in their low-intensity zone, with less than 25% of the time spent at moderate to high intensities. Aerobic fitness appears to determine the metabolic intensity that players can sustain throughout the game. PMID:26098638

Identification of target genes to control acetate yield during aerobic fermentation with Saccharomyces cerevisiae.

PubMed

Curiel, José Antonio; Salvadó, Zoel; Tronchoni, Jordi; Morales, Pilar; Rodrigues, Alda Joao; Quirós, Manuel; Gonzalez, Ramón

2016-09-15

Aerobic fermentation of grape must, leading to respiro-fermentative metabolism of sugars, has been proposed as way of reducing alcohol content in wines. Two factors limit the usefulness of Saccharomyces cerevisiae for this application, the Crabtree effect, and excess volatile acidity under aerobic conditions. This work aimed to explore the impact on ethanol acetate production of different S. cerevisiae strains deleted for genes previously related with the Crabtree phenotype. Recombinant strains were constructed on a wine industrial genetic background, FX10. All yeast strains, including FX10, showed respiro-fermentative metabolism in natural grape must under aerobic conditions, as well as a concomitant reduction in ethanol yield. This indicates that the Crabtree effect is not a major constrain for reaching relevant respiration levels in grape must. Indeed, only minor differences in ethanol yield were observed between the original and some of the recombinant strains. In contrast, some yeast strains showed a relevant reduction of acetic acid production. This was identified as a positive feature for the feasibility of alcohol level reduction by respiration. Reduced acetic acid production was confirmed by a thorough analysis of these and some additional deletion strains (involving genes HXK2, PYK1, REG1, PDE2 and PDC1). Some recombinant yeasts showed altered production of glycerol and pyruvate derived metabolites. REG1 and PDC1 deletion strains showed a strong reduction of acetic acid yield in aerobic fermentations. Since REG1 defective strains may be obtained by non-GMO approaches, these gene modifications show good promise to help reducing ethanol content in wines.

How does metabolism affect cell death in cancer?

PubMed

Villa, Elodie; Ricci, Jean-Ehrland

2016-07-01

In cancer research, identifying a specificity of tumor cells compared with 'normal' proliferating cells for targeted therapy is often considered the Holy Grail for researchers and clinicians. Although diverse in origin, most cancer cells share characteristics including the ability to escape cell death mechanisms and the utilization of different methods of energy production. In the current paradigm, aerobic glycolysis is considered the central metabolic characteristic of cancer cells (Warburg effect). However, recent data indicate that cancer cells also show significant changes in other metabolic pathways. Indeed, it was recently suggested that Kreb's cycle, pentose phosphate pathway intermediates, and essential and nonessential amino acids have key roles. Renewed interest in the fact that cancer cells have to reprogram their metabolism in order to proliferate or resist treatment must take into consideration the ability of tumor cells to adapt their metabolism to the local microenvironment (low oxygen, low nutrients). This variety of metabolic sources might be either a strength, resulting in infinite possibilities for adaptation and increased ability to resist chemotherapy-induced death, or a weakness that could be targeted to kill cancer cells. Here, we discuss recent insights showing how energetic metabolism may regulate cell death and how this might be relevant for cancer treatment. © 2015 FEBS.

Two Distinct Aerobic Methionine Salvage Pathways Generate Volatile Methanethiol in Rhodopseudomonas palustris

PubMed Central

Miller, Anthony R.; North, Justin A.; Wildenthal, John A.

2018-01-01

ABSTRACT 5′-Methyl-thioadenosine (MTA) is a dead-end, sulfur-containing metabolite and cellular inhibitor that arises from S-adenosyl-l-methionine-dependent reactions. Recent studies have indicated that there are diverse bacterial methionine salvage pathways (MSPs) for MTA detoxification and sulfur salvage. Here, via a combination of gene deletions and directed metabolite detection studies, we report that under aerobic conditions the facultatively anaerobic bacterium Rhodopseudomonas palustris employs both an MTA-isoprenoid shunt identical to that previously described in Rhodospirillum rubrum and a second novel MSP, both of which generate a methanethiol intermediate. The additional R. palustris aerobic MSP, a dihydroxyacetone phosphate (DHAP)-methanethiol shunt, initially converts MTA to 2-(methylthio)ethanol and DHAP. This is identical to the initial steps of the recently reported anaerobic ethylene-forming MSP, the DHAP-ethylene shunt. The aerobic DHAP-methanethiol shunt then further metabolizes 2-(methylthio)ethanol to methanethiol, which can be directly utilized by O-acetyl-l-homoserine sulfhydrylase to regenerate methionine. This is in contrast to the anaerobic DHAP-ethylene shunt, which metabolizes 2-(methylthio)ethanol to ethylene and an unknown organo-sulfur intermediate, revealing functional diversity in MSPs utilizing a 2-(methylthio)ethanol intermediate. When MTA was fed to aerobically growing cells, the rate of volatile methanethiol release was constant irrespective of the presence of sulfate, suggesting a general housekeeping function for these MSPs up through the methanethiol production step. Methanethiol and dimethyl sulfide (DMS), two of the most important compounds of the global sulfur cycle, appear to arise not only from marine ecosystems but from terrestrial ones as well. These results reveal a possible route by which methanethiol might be biologically produced in soil and freshwater environments. PMID:29636438

The cardiovascular and metabolic responses to Wii Fit video game playing in middle-aged and older adults.

PubMed

Guderian, B; Borreson, L A; Sletten, L E; Cable, K; Stecker, T P; Probst, M A; Dalleck, L C

2010-12-01

The purpose of this study was (a) to assess the cardiovascular and metabolic responses to Wii Fit video games and (b) to determine if Wii Fit video games meet the American College of Sports Medicine guidelines for improving and maintaining cardiorespiratory fitness. Twenty men and women (mean±SD age, height, and weight: = 58.1±8.8 years, 172.1±10.5 cm, 87.1±22.8 kg, respectively) completed a 20-min Wii Fit testing session consisting of six separate aerobic and balance games. Cardiovascular and metabolic data were collected via a portable calorimetric measurement system. Mean relative exercise intensity was 43.4±16.7% of heart rate reserve. Absolute exercise intensity in metabolic equivalents (METS) was 3.5±0.96. Total net energy expenditure for the Wii Fit video game playing session was 116.2±40.9 kcal/session. Results indicate that playing Wii Fit video games is a feasible alternative to more traditional aerobic exercise modalities for middle-aged and older adults that fulfills the American College of Sports Medicine guidelines for improving and maintaining cardiorespiratory fitness.

Ibogaine affects brain energy metabolism.

PubMed

Paskulin, Roman; Jamnik, Polona; Zivin, Marko; Raspor, Peter; Strukelj, Borut

2006-12-15

Ibogaine is an indole alkaloid present in the root of the plant Tabernanthe iboga. It is known to attenuate abstinence syndrome in animal models of drug addiction. Since the anti-addiction effect lasts longer than the presence of ibogaine in the body, some profound metabolic changes are expected. The aim of this study was to investigate the effect of ibogaine on protein expression in rat brains. Rats were treated with ibogaine at 20 mg/kg body weight i.p. and subsequently examined at 24 and 72 h. Proteins were extracted from whole brain and separated by two-dimensional (2-D) electrophoresis. Individual proteins were identified by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS). Enzymes of glycolysis and tricarboxylic acid (TCA) cycle namely glyceraldehyde-3-phosphate dehydrogenase, aldolase A, pyruvate kinase and malate dehydrogenase were induced. The results suggest that the remedial effect of ibogaine could be mediated by the change in energy availability. Since energy dissipating detoxification and reversion of tolerance to different drugs of abuse requires underlying functional and structural changes in the cell, higher metabolic turnover would be favourable. Understanding the pharmacodynamics of anti-addiction drugs highlights the subcellular aspects of addiction diseases, in addition to neurological and psychological perspectives.

Effects of a 12-week aerobic exercise intervention on eating behaviour, food cravings, and 7-day energy intake and energy expenditure in inactive men.

PubMed

Rocha, Joel; Paxman, Jenny; Dalton, Caroline; Winter, Edward; Broom, David R

2016-11-01

This study examined effects of 12 weeks of moderate-intensity aerobic exercise on eating behaviour, food cravings, and weekly energy intake and expenditure in inactive men. Eleven healthy men (mean ± SD: age, 26 ± 5 years; body mass index, 24.6 ± 3.8 kg·m -2 ; maximum oxygen uptake, 43.1 ± 7.4 mL·kg -1 ·min -1 ) completed the 12-week supervised exercise programme. Body composition, health markers (e.g., blood pressure), eating behaviour, food cravings, and weekly energy intake and expenditure were assessed before and after the exercise intervention. There were no intervention effects on weekly free-living energy intake (p = 0.326, d = -0.12) and expenditure (p = 0.799, d = 0.04) or uncontrolled eating and emotional eating scores (p > 0.05). However, there was a trend with a medium effect size (p = 0.058, d = 0.68) for cognitive restraint to be greater after the exercise intervention. Total food cravings (p = 0.009, d = -1.19) and specific cravings of high-fat foods (p = 0.023, d = -0.90), fast-food fats (p = 0.009, d = -0.71), and carbohydrates/starches (p = 0.009, d = -0.56) decreased from baseline to 12 weeks. Moreover, there was a trend with a large effect size for cravings of sweets (p = 0.052, d = -0.86) to be lower after the exercise intervention. In summary, 12 weeks of moderate-intensity aerobic exercise reduced food cravings and increased cognitive restraint, but these changes were not accompanied by changes in other eating behaviours or weekly energy intake and expenditure. The results indicate the importance of exercising for health improvements even when reductions in body mass are modest.

Aerobic expression of Vitreoscilla hemoglobin improves the growth performance of CHO-K1 cells.

PubMed

Juárez, Mariana; González-De la Rosa, Claudia H; Memún, Elisa; Sigala, Juan-Carlos; Lara, Alvaro R

2017-03-01

Inefficient carbon metabolism is a relevant issue during the culture of mammalian cells for the production of biopharmaceuticals. Therefore, cell engineering strategies to improve the metabolic and growth performance of cell lines are needed. The expression of Vitreoscilla stercoraria hemoglobin (VHb) has been shown to significantly reduce overflow metabolism and improve the aerobic growth of bacteria. However, the effects of VHb on mammalian cells have been rarely studied. Here, the impact of VHb on growth and lactate accumulation during CHO-K1 cell culture was investigated. For this purpose, CHO-K1 cells were transfected with plasmids carrying the vgb or gfp gene to express VHb or green fluorescence protein (GFP), respectively. VHb expression increased the specific growth rate and biomass yields on glucose and glutamine by 60 %, and reduced the amount of lactate produced per cell by 40 %, compared to the GFP-expression controls. Immunofluorescence microscopy showed that VHb is distributed in the cytoplasm and organelles, which support the hypothesis that VHb could serve as an oxygen carrier, enhancing aerobic respiration. These results are useful for the development of better producing cell lines for industrial applications. Copyright © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Physiological and functional diversity of phenol degraders isolated from phenol-grown aerobic granules: Phenol degradation kinetics and trichloroethylene co-metabolic activities.

PubMed

Zhang, Yi; Tay, Joo Hwa

2016-03-15

Aerobic granule is a novel form of microbial aggregate capable of degrading toxic and recalcitrant substances. Aerobic granules have been formed on phenol as the growth substrate, and used to co-metabolically degrade trichloroethylene (TCE), a synthetic solvent not supporting aerobic microbial growth. Granule formation process, rate limiting factors and the comprehensive toxic effects of phenol and TCE had been systematically studied. To further explore their potential at the level of microbial population and functions, phenol degraders were isolated and purified from mature granules in this study. Phenol and TCE degradation kinetics of 15 strains were determined, together with their TCE transformation capacities and other physiological characteristics. Isolation in the presence of phenol and TCE exerted stress on microbial populations, but the procedure was able to preserve their diversity. Wide variation was found with the isolates' kinetic behaviors, with the parameters often spanning 3 orders of magnitude. Haldane kinetics described phenol degradation well, and the isolates exhibited actual maximum phenol-dependent oxygen utilization rates of 9-449 mg DO g DW(-1) h(-1), in phenol concentration range of 4.8-406 mg L(-1). Both Michaelis-Menten and Haldane types were observed for TCE transformation, with the actual maximum rate of 1.04-21.1 mg TCE g DW(-1) h(-1) occurring between TCE concentrations of 0.42-4.90 mg L(-1). The TCE transformation capacities and growth yields on phenol ranged from 20-115 mg TCE g DW(-1) and 0.46-1.22 g DW g phenol(-1), respectively, resulting in TCE transformation yields of 10-70 mg TCE g phenol(-1). Contact angles of the isolates were between 34° and 82°, suggesting both hydrophobic and hydrophilic cell surface. The diversity in the isolates is a great advantage, as it enables granules to be versatile and adaptive under different operational conditions. Copyright © 2015 Elsevier Ltd. All rights reserved.

Energy system contribution to 400-metre and 800-metre track running.

PubMed

Duffield, Rob; Dawson, Brian; Goodman, Carmel

2005-03-01

As a wide range of values has been reported for the relative energetics of 400-m and 800-m track running events, this study aimed to quantify the respective aerobic and anaerobic energy contributions to these events during track running. Sixteen trained 400-m (11 males, 5 females) and 11 trained 800-m (9 males, 2 females) athletes participated in this study. The participants performed (on separate days) a laboratory graded exercsie test and multiple race time-trials. The relative energy system contribution was calculated by multiple methods based upon measures of race VO2, accumulated oxygen deficit (AOD), blood lactate and estimated phosphocreatine degradation (lactate/PCr). The aerobic/anaerobic energy system contribution (AOD method) to the 400-m event was calculated as 41/59% (male) and 45/55% (female). For the 800-m event, an increased aerobic involvement was noted with a 60/40% (male) and 70/30% (female) respective contribution. Significant (P < 0.05) negative correlations were noted between race performance and anaerobic energy system involvement (lactate/PCr) for the male 800-m and female 400-m events (r = - 0.77 and - 0.87 respectively). These track running data compare well with previous estimates of the relative energy system contributions to the 400-m and 800-m events. Additionally, the relative importance and speed of interaction of the respective metabolic pathways has implications to training for these events.

Emerging role of the brain in the homeostatic regulation of energy and glucose metabolism.

PubMed

Roh, Eun; Song, Do Kyeong; Kim, Min-Seon

2016-03-11

Accumulated evidence from genetic animal models suggests that the brain, particularly the hypothalamus, has a key role in the homeostatic regulation of energy and glucose metabolism. The brain integrates multiple metabolic inputs from the periphery through nutrients, gut-derived satiety signals and adiposity-related hormones. The brain modulates various aspects of metabolism, such as food intake, energy expenditure, insulin secretion, hepatic glucose production and glucose/fatty acid metabolism in adipose tissue and skeletal muscle. Highly coordinated interactions between the brain and peripheral metabolic organs are critical for the maintenance of energy and glucose homeostasis. Defective crosstalk between the brain and peripheral organs contributes to the development of obesity and type 2 diabetes. Here we comprehensively review the above topics, discussing the main findings related to the role of the brain in the homeostatic regulation of energy and glucose metabolism.

Emerging role of the brain in the homeostatic regulation of energy and glucose metabolism

PubMed Central

Roh, Eun; Song, Do Kyeong; Kim, Min-Seon

2016-01-01

Accumulated evidence from genetic animal models suggests that the brain, particularly the hypothalamus, has a key role in the homeostatic regulation of energy and glucose metabolism. The brain integrates multiple metabolic inputs from the periphery through nutrients, gut-derived satiety signals and adiposity-related hormones. The brain modulates various aspects of metabolism, such as food intake, energy expenditure, insulin secretion, hepatic glucose production and glucose/fatty acid metabolism in adipose tissue and skeletal muscle. Highly coordinated interactions between the brain and peripheral metabolic organs are critical for the maintenance of energy and glucose homeostasis. Defective crosstalk between the brain and peripheral organs contributes to the development of obesity and type 2 diabetes. Here we comprehensively review the above topics, discussing the main findings related to the role of the brain in the homeostatic regulation of energy and glucose metabolism. PMID:26964832

BAG3 directly stabilizes Hexokinase 2 mRNA and promotes aerobic glycolysis in pancreatic cancer cells.

PubMed

An, Ming-Xin; Li, Si; Yao, Han-Bing; Li, Chao; Wang, Jia-Mei; Sun, Jia; Li, Xin-Yu; Meng, Xiao-Na; Wang, Hua-Qin

2017-12-04

Aerobic glycolysis, a phenomenon known historically as the Warburg effect, is one of the hallmarks of cancer cells. In this study, we characterized the role of BAG3 in aerobic glycolysis of pancreatic ductal adenocarcinoma (PDAC) and its molecular mechanisms. Our data show that aberrant expression of BAG3 significantly contributes to the reprogramming of glucose metabolism in PDAC cells. Mechanistically, BAG3 increased Hexokinase 2 (HK2) expression, the first key enzyme involved in glycolysis, at the posttranscriptional level. BAG3 interacted with HK2 mRNA, and the degree of BAG3 expression altered recruitment of the RNA-binding proteins Roquin and IMP3 to the HK2 mRNA. BAG3 knockdown destabilized HK2 mRNA via promotion of Roquin recruitment, whereas BAG3 overexpression stabilized HK2 mRNA via promotion of IMP3 recruitment. Collectively, our results show that BAG3 promotes reprogramming of glucose metabolism via interaction with HK2 mRNA in PDAC cells, suggesting that BAG3 may be a potential target in the aerobic glycolysis pathway for developing novel anticancer agents. © 2017 An et al.

State-dependent metabolic partitioning and energy conservation: A theoretical framework for understanding the function of sleep.

PubMed

Schmidt, Markus H; Swang, Theodore W; Hamilton, Ian M; Best, Janet A

2017-01-01

Metabolic rate reduction has been considered the mechanism by which sleep conserves energy, similar to torpor or hibernation. This mechanism of energy savings is in conflict with the known upregulation (compared to wake) of diverse functions during sleep and neglects a potential role in energy conservation for partitioning of biological operations by behavioral state. Indeed, energy savings as derived from state-dependent resource allocations have yet to be examined. A mathematical model is presented based on relative rates of energy deployment for biological processes upregulated during either wake or sleep. Using this model, energy savings from sleep-wake cycling over constant wakefulness is computed by comparing stable limit cycles for systems of differential equations. A primary objective is to compare potential energy savings derived from state-dependent metabolic partitioning versus metabolic rate reduction. Additionally, energy conservation from sleep quota and the circadian system are also quantified in relation to a continuous wake condition. As a function of metabolic partitioning, our calculations show that coupling of metabolic operations with behavioral state may provide comparatively greater energy savings than the measured decrease in metabolic rate, suggesting that actual energy savings derived from sleep may be more than 4-fold greater than previous estimates. A combination of state-dependent metabolic partitioning and modest metabolic rate reduction during sleep may enhance energy savings beyond what is achievable through metabolic partitioning alone; however, the relative contribution from metabolic partitioning diminishes as metabolic rate is decreased during the rest phase. Sleep quota and the circadian system further augment energy savings in the model. Finally, we propose that state-dependent resource allocation underpins both sleep homeostasis and the optimization of daily energy conservation across species. This new paradigm identifies an

Energy metabolism of intervertebral disc under mechanical loading.

PubMed

Wang, Chong; Gonzales, Silvia; Levene, Howard; Gu, Weiyong; Huang, Chun-Yuh Charles

2013-11-01

Intervertebral disc (IVD) degeneration is closely associated with low back pain (LBP), which is a major health concern in the U.S. Cellular biosynthesis of extracellular matrix (ECM), which is important for maintaining tissue integrity and preventing tissue degeneration, is an energy demanding process. Due to impaired nutrient support in avascular IVD, adenosine triphosphate (ATP) supply could be a limiting factor for maintaining normal ECM synthesis. Therefore, the objective of this study was to investigate the energy metabolism in the annulus fibrosus (AF) and nucleus pulposus (NP) of porcine IVD under static and dynamic compressions. Under compression, pH decreased and the contents of lactate and ATP increased significantly in both AF and NP regions, suggesting that compression can promote ATP production via glycolysis and reduce pH by increasing lactate accumulation. A high level of extracellular ATP content was detected in the NP region and regulated by compressive loading. Since ATP can serve not only as an intra-cellular energy currency, but also as a regulator of a variety of cellular activities extracellularly through the purinergic signaling pathway, our findings suggest that compression-mediated ATP metabolism could be a novel mechanobiological pathway for regulating IVD metabolism. © 2013 Orthopaedic Research Society.

Aerobic Activity Preferences among Older Canadians: A Time Use Perspective.

PubMed

Spinney, Jamie E L

2013-12-01

Numerous health benefits are associated with a physically active population. This study sought to discover the aerobic activity preferences among older Canadians. Four cycles of nationally representative time use data were fused with energy expenditure information to determine both participation rates and time spent in the 10 most frequently reported aerobic activities. Aerobic activity preferences are dominated by domestic chores (15% to 30% participation for about two hours per day), recreational walking (15% to 30% participation for about one hour per day), and active transportation (generally less than 5% participation for less than 30 minutes per day). Although there have been several changes in older Canadians’ revealed preferences for aerobic activities over the past three decades, the prevalence of domestic chores points towards the importance of policies that support older Canadians remaining in their homes, whereas the popularity of walking suggests that “walkability” needs to be considered in neighbourhood design.

Is Low-Impact Aerobic Dance an Effective Cardiovascular Workout?

ERIC Educational Resources Information Center

Williford, Henry N.; And Others

1989-01-01

Presents results of an investigation comparing energy cost and cardiovascular responses of aerobic dance routines performed at different intensity levels in varying amounts of energy expenditure. For low-impact dance to meet minimum guidelines suggested by the American College of Sports Medicine, it should be performed at high intensity. (SM)

Developmental Hypoxia Has Negligible Effects on Long-Term Hypoxia Tolerance and Aerobic Metabolism of Atlantic Salmon (Salmo salar).

PubMed

Wood, Andrew T; Clark, Timothy D; Andrewartha, Sarah J; Elliott, Nicholas G; Frappell, Peter B

Exposure to developmental hypoxia can have long-term impacts on the physiological performance of fish because of irreversible plasticity. Wild and captive-reared Atlantic salmon (Salmo salar) can be exposed to hypoxic conditions during development and continue to experience fluctuating oxygen levels as juveniles and adults. Here, we examine whether developmental hypoxia impacts subsequent hypoxia tolerance and aerobic performance of Atlantic salmon. Individuals at 8°C were exposed to 50% (hypoxia) or 100% (normoxia) dissolved oxygen (DO) saturation (as percent of air saturation) from fertilization for ∼100 d (800 degree days) and then raised in normoxic conditions for a further 15 mo. At 18 mo after fertilization, aerobic scope was calculated in normoxia (100% DO) and acute (18 h) hypoxia (50% DO) from the difference between the minimum and maximum oxygen consumption rates ([Formula: see text] and [Formula: see text], respectively) at 10°C. Hypoxia tolerance was determined as the DO at which loss of equilibrium (LOE) occurred in a constantly decreasing DO environment. There was no difference in [Formula: see text], [Formula: see text], or aerobic scope between fish raised in hypoxia or normoxia. There was some evidence that hypoxia tolerance was lower (higher DO at LOE) in hypoxia-raised fish compared with those raised in normoxia, but the magnitude of the effect was small (12.52% DO vs. 11.73% DO at LOE). Acute hypoxia significantly reduced aerobic scope by reducing [Formula: see text], while [Formula: see text] remained unchanged. Interestingly, acute hypoxia uncovered individual-level relationships between DO at LOE and [Formula: see text], [Formula: see text], and aerobic scope. We discuss our findings in the context of developmental trajectories and the role of aerobic performance in hypoxia tolerance.

Energy requirements, protein-energy metabolism and balance, and carbohydrates in preterm infants.

PubMed

Hay, William W; Brown, Laura D; Denne, Scott C

2014-01-01

Energy is necessary for all vital functions of the body at molecular, cellular, organ, and systemic levels. Preterm infants have minimum energy requirements for basal metabolism and growth, but also have requirements for unique physiology and metabolism that influence energy expenditure. These include body size, postnatal age, physical activity, dietary intake, environmental temperatures, energy losses in the stool and urine, and clinical conditions and diseases, as well as changes in body composition. Both energy and protein are necessary to produce normal rates of growth. Carbohydrates (primarily glucose) are principle sources of energy for the brain and heart until lipid oxidation develops over several days to weeks after birth. A higher protein/energy ratio is necessary in most preterm infants to approximate normal intrauterine growth rates. Lean tissue is predominantly produced during early gestation, which continues through to term. During later gestation, fat accretion in adipose tissue adds increasingly large caloric requirements to the lean tissue growth. Once protein intake is sufficient to promote net lean body accretion, additional energy primarily produces more body fat, which increases almost linearly at energy intakes >80-90 kcal/kg/day in normal, healthy preterm infants. Rapid gains in adiposity have the potential to produce later life obesity, an increasingly recognized risk of excessive energy intake. In addition to fundamental requirements for glucose, protein, and fat, a variety of non-glucose carbohydrates found in human milk may have important roles in promoting growth and development, as well as production of a gut microbiome that could protect against necrotizing enterocolitis. © 2014 S. Karger AG, Basel.

Mitochondrial Energy Metabolism and Redox Signaling in Brain Aging and Neurodegeneration

PubMed Central

Yin, Fei; Boveris, Alberto

2014-01-01

Abstract Significance: The mitochondrial energy-transducing capacity is essential for the maintenance of neuronal function, and the impairment of energy metabolism and redox homeostasis is a hallmark of brain aging, which is particularly accentuated in the early stages of neurodegenerative diseases. Recent Advances: The communications between mitochondria and the rest of the cell by energy- and redox-sensitive signaling establish a master regulatory device that controls cellular energy levels and the redox environment. Impairment of this regulatory devise is critical for aging and the early stages of neurodegenerative diseases. Critical Issues: This review focuses on a coordinated metabolic network—cytosolic signaling, transcriptional regulation, and mitochondrial function—that controls the cellular energy levels and redox status as well as factors which impair this metabolic network during brain aging and neurodegeneration. Future Directions: Characterization of mitochondrial function and mitochondria-cytosol communications will provide pivotal opportunities for identifying targets and developing new strategies aimed at restoring the mitochondrial energy-redox axis that is compromised in brain aging and neurodegeneration. Antioxid. Redox Signal. 20, 353–371. PMID:22793257

Aerobic characteristics of red kangaroo skeletal muscles: is a high aerobic capacity matched by muscle mitochondrial and capillary morphology as in placental mammals?

PubMed

Dawson, Terence J; Mifsud, Brock; Raad, Matthew C; Webster, Koa N

2004-07-01

Marsupials and placentals together comprise the Theria, the advanced mammals, but they have had long independent evolutionary histories, with the last common ancestor occurring more than 125 million years ago. Although in the past the marsupials were considered to be metabolically 'primitive', the red kangaroo Macropus rufus has been reported to have an aerobic capacity (VO2max) comparable to that of the most 'athletic' of placentals such as dogs. However, kangaroos travel at moderate speeds with lower relative cost than quadrupedal placentals. Given the long independent evolution of the two therian groups, and their unusual locomotor energetics, do kangaroos achieve their high aerobic capacity using the same structural and functional mechanisms used by (athletic) placentals? Red kangaroo skeletal muscle morphometry matched closely the general aerobic characteristics of placental mammals. The relationship between total mitochondrial volume in skeletal muscle and VO2max during exercise was identical to that in quadrupedal placentals, and differed from that in bipedal humans. As for placentals generally, red kangaroo mitochondrial oxygen consumption at VO2max was 4.7 ml O2 min(-1) ml(-1) of mitochondria. Also, the inner mitochondrial membrane densities were 35.8 +/- 0.7 m2 ml(-1) of mitochondria, which is the same as for placental mammals, and the same pattern of similarity was seen for capillary densities and volumes. The overall data for kangaroos was equivalent to that seen in athletic placentals such as dogs and pronghorns. Total skeletal muscle mass was high, being around 50% of body mass, and was concentrated around the pelvis and lower back. The majority of the muscles sampled had relatively high mitochondrial volume densities, in the range 8.8-10.6% in the major locomotor muscles. Again, capillary densities and capillary blood volumes followed the pattern seen for mitochondria. Our results indicate that the red kangaroo, despite its locomotion and extreme

Endurance Exercise Improves Molecular Pathways of Aerobic Metabolism in Patients With Myositis.

PubMed

Munters, Li Alemo; Loell, Ingela; Ossipova, Elena; Raouf, Joan; Dastmalchi, Maryam; Lindroos, Eva; Chen, Yi-Wen; Esbjörnsson, Mona; Korotkova, Marina; Alexanderson, Helene; Nagaraju, Kanneboyina; Crofford, Leslie J; Jakobsson, Per-Johan; Lundberg, Ingrid E

2016-07-01

Endurance exercise demonstrates beneficial effects in polymyositis/dermatomyositis (PM/DM); however, the molecular effects of exercise on skeletal muscle are incompletely understood. We undertook this controlled pilot study to investigate the effects of a 12-week endurance exercise training program on the molecular profile of skeletal muscle in patients with established PM/DM compared to a nonexercised control group of patients with established PM/DM. Fifteen patients (7 in the exercise group and 8 in the control group) with paired baseline and 12-week follow-up muscle biopsy samples were included. Messenger RNA expression profiling, mass spectrometry-based quantitative proteomics, and immunohistochemical analyses were performed on muscle biopsy samples to determine molecular adaptations associated with changes in clinical measurements induced by endurance exercise. Compared to the control group, the exercise group improved in minutes of cycling time (P < 0.01) and Vo2 max (P < 0.05). The exercise group also had reduced disease activity (P < 0.05) and reduced lactate levels at exhaustion (P < 0.05). Genes related to capillary growth, mitochondrial biogenesis, protein synthesis, cytoskeletal remodeling, and muscle hypertrophy were up-regulated in the exercise group, while genes related to inflammation/immune response and endoplasmic reticulum stress were down-regulated. Mitochondrial pathways including the oxidative phosphorylation metabolic pathway were most affected by the endurance exercise, as demonstrated by proteomics analysis. The exercise group also showed a higher number of capillaries per mm(2) in follow-up biopsy samples (P < 0.05). Our data indicate that endurance exercise in patients with established PM and DM may activate an aerobic phenotype and promote muscle growth and simultaneously suppress the inflammatory response in these patients' muscles, as supported by a combination of data on gene expression, proteomics, and capillary

[Modifications in myocardial energy metabolism in diabetic patients

NASA Technical Reports Server (NTRS)

Grynberg, A.

2001-01-01

The capacity of cardiac myocyte to regulate ATP production to face any change in energy demand is a major determinant of cardiac function. Because FA is the main heart fuel (although the most expensive one in oxygen, and prompt to induce deleterious effects), this process is based on a balanced fatty acid (FA) metabolism. Several pathological situations are associated with an accumulation of FA or derivatives, or with an excessive b-oxidation. The diabetic cardiomyocyte is characterised by an over consumption of FA. The control of the FA/glucose balance clearly appears as a new strategy for cytoprotection, particularly in diabetes and requires a reduced FA contribution to ATP production. Cardiac myocytes can control FA mitochondrial entry, but display weak ability to control FA uptake, thus the fate of non beta-oxidized FA appear as a new impairment for the cell. Both the trigger and the regulation of cardiac contraction result from membrane activity, and the other major FA function in the myocardium is their role in membrane homeostasis, through the phospholipid synthesis and remodeling pathways. Sudden death, hypercatecholaminemia, diabetes and heart failure have been associated with an altered PUFA content in cardiac membranes. Experimental data suggest that the 2 metabolic pathways involved in membrane homeostasis may represent therapeutic targets for cytoprotection. The drugs that increase cardiac phospholipid turnover (trimetazidine, ranolazine,...) display anti-ischemic non hemodynamic effect. This effect is based on a redirection of FA utilization towards phospholipid synthesis, which decrease their availability for energy production. A nutritional approach gave also promising results. Besides its anti-arrhythmic effect, the dietary docosahexaenoic acid is able to reduce FA energy consumption and hence oxygen demand. The cardiac metabolic pathways involving FA should be considered as a whole, precariously balanced. The diabetic heart being characterised by

Hexokinase II acts through UCP3 to suppress mitochondrial reactive oxygen species production and maintain aerobic respiration.

PubMed

Mailloux, Ryan J; Dumouchel, Tyler; Aguer, Céline; deKemp, Rob; Beanlands, Rob; Harper, Mary-Ellen

2011-07-15

UCP3 (uncoupling protein-3) mitigates mitochondrial ROS (reactive oxygen species) production, but the mechanisms are poorly understood. Previous studies have also examined UCP3 effects, including decreased ROS production, during metabolic states when fatty acid oxidation is high (e.g. a fasting state). However, the role of UCP3 when carbohydrate oxidation is high (e.g. fed state) has remained largely unexplored. In the present study, we show that mitochondrial-bound HK (hexokinase) II curtails oxidative stress and enhances aerobic metabolism of glucose in the fed state in a UCP3-dependent manner. Genetic knockout or inhibition of UCP3 significantly decreased mitochondrial-bound HKII. Furthermore, UCP3 was required for the HKII-mediated decrease in mitochondrial ROS emission. Intriguingly, the UCP3-mediated modulation of mitochondria-associated HKII was only observed in cells cultured under high-glucose conditions. UCP3 was required to maintain high rates of aerobic metabolism in high-glucose-treated cells and in muscle of fed mice. Deficiency in UCP3 resulted in a metabolic shift that favoured anaerobic glycolytic metabolism, increased glucose uptake and increased sensitivity to oxidative challenge. PET (positron emission tomography) of [18F]fluoro-deoxyglucose uptake confirmed these findings in UCP3-knockout and wild-type mice. Collectively, our findings link the anti-oxidative and metabolic functions of UCP3 through a surprising molecular connection with mitochondrial-bound HKII.

Teaching Aerobic Lifestyles: New Perspectives.

ERIC Educational Resources Information Center

Goodrick, G. Ken; Iammarino, Nicholas K.

1982-01-01

New approaches to teaching aerobic life-styles in secondary schools are suggested, focusing on three components: (1) the psychological benefits of aerobic activity; (2) alternative aerobic programs at nonschool locations; and (3) the development of an aerobics curriculum to help maintain an active life-style after graduation. (JN)

Cellular energy metabolism maintains young status in old queen honey bees (Apis mellifera).

PubMed

Lu, Cheng-Yen; Qiu, Jiantai Timothy; Hsu, Chin-Yuan

2018-05-02

Trophocytes and oenocytes of queen honey bees are used in studies of cellular longevity, but their cellular energy metabolism with age is poorly understood. In this study, the molecules involved in cellular energy metabolism were evaluated in the trophocytes and oenocytes of young and old queen bees. The findings indicated that there were no significant differences between young and old queen bees in β-oxidation, glycolysis, and protein synthesis. These results indicate that the cellular energy metabolism of trophocytes and oenocytes in old queen bees is similar to young queen bees and suggests that maintaining cellular energy metabolism in a young status may be associated with the longevity of queen bees. Fat and glycogen accumulation increased with age indicating that old queen bees are older than young queen bees. © 2018 Wiley Periodicals, Inc.

Metabolomics Analysis of Cistus monspeliensis Leaf Extract on Energy Metabolism Activation in Human Intestinal Cells

PubMed Central

Shimoda, Yoichi; Han, Junkyu; Kawada, Kiyokazu; Smaoui, Abderrazak; Isoda, Hiroko

2012-01-01

Energy metabolism is a very important process to improve and maintain health from the point of view of physiology. It is well known that the intracellular ATP production is contributed to energy metabolism in cells. Cistus monspeliensis is widely used as tea, spices, and medical herb; however, it has not been focusing on the activation of energy metabolism. In this study, C. monspeliensis was investigated as the food resources by activation of energy metabolism in human intestinal epithelial cells. C. monspeliensis extract showed high antioxidant ability. In addition, the promotion of metabolites of glycolysis and TCA cycle was induced by C. monspeliensis treatment. These results suggest that C. monspeliensis extract has an ability to enhance the energy metabolism in human intestinal cells. PMID:22523469

Energy metabolism, fuel selection and body weight regulation

PubMed Central

Galgani, J; Ravussin, E

2010-01-01

Energy homeostasis is critical for the survival of species. Therefore, multiple and complex mechanisms have evolved to regulate energy intake and expenditure to maintain body weight. For weight maintenance, not only does energy intake have to match energy expenditure, but also macronutrient intake must balance macronutrient oxidation. However, this equilibrium seems to be particularly difficult to achieve in individuals with low fat oxidation, low energy expenditure, low sympathetic activity or low levels of spontaneous physical activity, as in addition to excess energy intake, all of these factors explain the tendency of some people to gain weight. Additionally, large variability in weight change is observed when energy surplus is imposed experimentally or spontaneously. Clearly, the data suggest a strong genetic influence on body weight regulation implying a normal physiology in an ‘obesogenic’ environment. In this study, we also review evidence that carbohydrate balance may represent the potential signal that regulates energy homeostasis by impacting energy intake and body weight. Because of the small storage capacity for carbohydrate and its importance for metabolism in many tissues and organs, carbohydrate balance must be maintained at a given level. This drive for balance may in turn cause increased energy intake when consuming a diet high in fat and low in carbohydrate. If sustained over time, such an increase in energy intake cannot be detected by available methods, but may cause meaningful increases in body weight. The concept of metabolic flexibility and its impact on body weight regulation is also presented. PMID:19136979

Differences in the metabolic response to temperature acclimation in nine-spined stickleback (Pungitius pungitius) populations from contrasting thermal environments.

PubMed

Bruneaux, Matthieu; Nikinmaa, Mikko; Laine, Veronika N; Lindström, Kai; Primmer, Craig R; Vasemägi, Anti

2014-12-01

Metabolic responses to temperature changes are crucial for maintaining the energy balance of an individual under seasonal temperature fluctuations. To understand how such responses differ in recently isolated populations (<11,000 years), we studied four Baltic populations of the nine-spined stickleback (Pungitius pungitius L.) from coastal locations (seasonal temperature range, 0-29°C) and from colder, more thermally stable spring-fed ponds (1-19°C). Salinity and predation pressure also differed between these locations. We acclimatized wild-caught fish to 6, 11, and 19°C in common garden conditions for 4-6 months and determined their aerobic scope and hepatosomatic index (HSI). The freshwater fish from the colder (2-14°C), predator-free pond population exhibited complete temperature compensation for their aerobic scope, whereas the coastal populations underwent metabolic rate reduction during the cold treatment. Coastal populations had higher HSI than the colder pond population at all temperatures, with cold acclimation accentuating this effect. The metabolic rates and HSI for freshwater fish from the pond with higher predation pressure were more similar to those of the coastal ones. Our results suggest that ontogenic effects and/or genetic differentiation are responsible for differential energy storage and metabolic responses between these populations. This work demonstrates the metabolic versatility of the nine-spined stickleback and the pertinence of an energetic framework to better understand potential local adaptations. It also demonstrates that instead of using a single acclimation temperature thermal reaction norms should be compared when studying individuals originating from different thermal environments in a common garden setting. © 2014 Wiley Periodicals, Inc.

Aerobic mitochondria of parasitic protists: Diverse genomes and complex functions.

PubMed

Zíková, Alena; Hampl, Vladimír; Paris, Zdeněk; Týč, Jiří; Lukeš, Julius

In this review the main features of the mitochondria of aerobic parasitic protists are discussed. While the best characterized organelles are by far those of kinetoplastid flagellates and Plasmodium, we also consider amoebae Naegleria and Acanthamoeba, a ciliate Ichthyophthirius and related lineages. The simplistic view of the mitochondrion as just a power house of the cell has already been abandoned in multicellular organisms and available data indicate that this also does not apply for protists. We discuss in more details the following mitochondrial features: genomes, post-transcriptional processing, translation, biogenesis of iron-sulfur complexes, heme metabolism and the electron transport chain. Substantial differences in all these core mitochondrial features between lineages are compatible with the view that aerobic protists harbor organelles that are more complex and flexible than previously appreciated. Copyright © 2016 Elsevier B.V. All rights reserved.

Exercise training dose differentially alters muscle and heart capillary density and metabolic functions in an obese rat with metabolic syndrome.

PubMed

Machado, Marcus Vinicius; Vieira, Aline Bomfim; da Conceição, Fabiana Gomes; Nascimento, Alessandro Rodrigues; da Nóbrega, Antonio Claudio Lucas; Tibirica, Eduardo

2017-12-01

What is the central question of this study? Regular exercise is recommended as a non-pharmacological approach for the prevention and treatment of metabolic syndrome. However, the impact of different combinations of intensity, duration and frequency of exercise on metabolic syndrome and microvascular density has not been reported. What is the main finding and its importance? We provide evidence on the impact of aerobic exercise dose on metabolic and microvascular alterations in an experimental model of metabolic syndrome induced by high-fat diet. We found that the exercise frequency and duration were the main factors affecting anthropometric and metabolic parameters and microvascular density in the skeletal muscle. Exercise intensity was related only to microvascular density in the heart. We evaluated the effect of the frequency, duration and intensity of exercise training on metabolic parameters and structural capillary density in obese rats with metabolic syndrome. Wistar-Kyoto rats were fed either a standard commercial diet (CON) or a high-fat diet (HFD). Animals that received the HFD were randomly separated into either a sedentary (SED) group or eight different exercise groups that varied according to the frequency, duration and intensity of training. After 12 weeks of aerobic exercise training, the body composition, aerobic capacity, haemodynamic variables, metabolic parameters and capillary density in the heart and skeletal muscle were evaluated. All the exercise training groups showed reduced resting systolic blood pressure and heart rate and normalized fasting glucose. The minimal amount of exercise (90 min per week) produced little effect on metabolic syndrome parameters. A moderate amount of exercise (150 min per week) was required to reduce body weight and improve capillary density. However, only the high amount of exercise (300 min per week) significantly reduced the amount of body fat depots. The three-way ANOVA showed a main effect of exercise

Velocity, aerobic power and metabolic cost of whole body and arms only front crawl swimming at various stroke rates.

PubMed

Morris, Kirstin S; Osborne, Mark A; Shephard, Megan E; Skinner, Tina L; Jenkins, David G

2016-05-01

Stroke rate (SR) has not been considered in previous research examining the relative roles of the limbs in front-crawl performance. This study compared velocity, aerobic power ([Formula: see text]) and metabolic cost (C) between whole body (WB) and arms only (AO) front-crawl swimming across various intensities while controlling SR. Twenty Australian national swimmers performed six 200 m front-crawl efforts under two conditions: (1) WB swimming and, (2) AO swimming. Participants completed the 200 m trials under three SR conditions: "low" (22-26 stroke-cycles min(-1)), "moderate" (30-34 stroke-cycles min(-1) and "high" (38-42 stroke-cycles min(-1)). [Formula: see text] was continuously measured, with C, velocity, SR, and kick rate calculated for each effort. Regardless of the SR condition and sex, AO velocity was consistently lower than WB velocity by ~11.0 % (p < 0.01). AO [Formula: see text] was lower than WB [Formula: see text] at all SR conditions for females (p < 0.01) and at the "high" SR for males (p < 0.01). C did not differ between WB and AO at any SR for both sexes (p > 0.01). When C was expressed as a function of velocity, WB and AO regression equations differed for males (p = 0.01) but not for females (p = 0.087). Kick rate increased as SR increased (p < 0.01), though the kick-to-stroke rate ratio remained constant. Elite swimmers gain ~11 % in velocity from their kick and, when used in conjunction with the arm stroke at the swimmers' preferred frequency, the metabolic cost of WB and AO swimming is the same. Coaches should consider these results when prescribing AO sets if their intention is to reduce the metabolic load.

A comparative meta-analysis of maximal aerobic metabolism of vertebrates: implications for respiratory and cardiovascular limits to gas exchange.

PubMed

Hillman, Stanley S; Hancock, Thomas V; Hedrick, Michael S

2013-02-01

Maximal aerobic metabolic rates (MMR) in vertebrates are supported by increased conductive and diffusive fluxes of O(2) from the environment to the mitochondria necessitating concomitant increases in CO(2) efflux. A question that has received much attention has been which step, respiratory or cardiovascular, provides the principal rate limitation to gas flux at MMR? Limitation analyses have principally focused on O(2) fluxes, though the excess capacity of the lung for O(2) ventilation and diffusion remains unexplained except as a safety factor. Analyses of MMR normally rely upon allometry and temperature to define these factors, but cannot account for much of the variation and often have narrow phylogenetic breadth. The unique aspect of our comparative approach was to use an interclass meta-analysis to examine cardio-respiratory variables during the increase from resting metabolic rate to MMR among vertebrates from fish to mammals, independent of allometry and phylogeny. Common patterns at MMR indicate universal principles governing O(2) and CO(2) transport in vertebrate cardiovascular and respiratory systems, despite the varied modes of activities (swimming, running, flying), different cardio-respiratory architecture, and vastly different rates of metabolism (endothermy vs. ectothermy). Our meta-analysis supports previous studies indicating a cardiovascular limit to maximal O(2) transport and also implicates a respiratory system limit to maximal CO(2) efflux, especially in ectotherms. Thus, natural selection would operate on the respiratory system to enhance maximal CO(2) excretion and the cardiovascular system to enhance maximal O(2) uptake. This provides a possible evolutionary explanation for the conundrum of why the respiratory system appears functionally over-designed from an O(2) perspective, a unique insight from previous work focused solely on O(2) fluxes. The results suggest a common gas transport blueprint, or Bauplan, in the vertebrate clade.

Metabolic sensing neurons and the control of energy homeostasis.

PubMed

Levin, Barry E

2006-11-30

The brain and periphery carry on a constant conversation; the periphery informs the brain about its metabolic needs and the brain provides for these needs through its control of somatomotor, autonomic and neurohumoral pathways involved in energy intake, expenditure and storage. Metabolic sensing neurons are the integrators of a variety of metabolic, humoral and neural inputs from the periphery. Such neurons, originally called "glucosensing", also respond to fatty acids, hormones and metabolites from the periphery. They are integrated within neural pathways involved in the regulation of energy homeostasis. Unlike most neurons, they utilize glucose and other metabolites as signaling molecules to regulate their membrane potential and firing rate. For glucosensing neurons, glucokinase acts as the rate-limiting step in glucosensing while the pathways that mediate responses to metabolites like lactate, ketone bodies and fatty acids are less well characterized. Many metabolic sensing neurons also respond to insulin and leptin and other peripheral hormones and receive neural inputs from peripheral organs. Each set of afferent signals arrives with different temporal profiles and by different routes and these inputs are summated at the level of the membrane potential to produce a given neural firing pattern. In some obese individuals, the relative sensitivity of metabolic sensing neurons to various peripheral inputs is genetically reduced. This may provide one mechanism underlying their propensity to become obese when exposed to diets high in fat and caloric density. Thus, metabolic sensing neurons may provide a potential therapeutic target for the treatment of obesity.

Aerobic exercise (image)

MedlinePlus

Aerobic exercise gets the heart working to pump blood through the heart more quickly and with more ... must be oxygenated more quickly, which quickens respiration. Aerobic exercise strengthens the heart and boosts healthy cholesterol ...

Estimation of metabolic energy expenditure from core temperature using a human thermoregulatory model

USDA-ARS?s Scientific Manuscript database

Measuring metabolic energy expenditure in humans may provide a means of monitoring and reducing obesity, estimating nutritional requirements, reducing obesity, maintaining energy balance during athletics, and modeling human thermoregulatory responses. However, measuring metabolic rate (M) is challen...

Lower white blood cell counts in elite athletes training for highly aerobic sports.

PubMed

Horn, P L; Pyne, D B; Hopkins, W G; Barnes, C J

2010-11-01

White cell counts at rest might be lower in athletes participating in selected endurance-type sports. Here, we analysed blood tests of elite athletes collected over a 10-year period. Reference ranges were established for 14 female and 14 male sports involving 3,679 samples from 937 females and 4,654 samples from 1,310 males. Total white blood cell counts and counts of neutrophils, lymphocytes and monocytes were quantified. Each sport was scaled (1-5) for its perceived metabolic stress (aerobic-anaerobic) and mechanical stress (concentric-eccentric) by 13 sports physiologists. Substantially lower total white cell and neutrophil counts were observed in aerobic sports of cycling and triathlon (~16% of test results below the normal reference range) compared with team or skill-based sports such as water polo, cricket and volleyball. Mechanical stress of sports had less effect on the distribution of cell counts. The lower white cell counts in athletes in aerobic sports probably represent an adaptive response, not underlying pathology.

Teaching Aerobic Fitness Concepts.

ERIC Educational Resources Information Center

Sander, Allan N.; Ratliffe, Tom

2002-01-01

Discusses how to teach aerobic fitness concepts to elementary students. Some of the K-2 activities include location, size, and purpose of the heart and lungs; the exercise pulse; respiration rate; and activities to measure aerobic endurance. Some of the 3-6 activities include: definition of aerobic endurance; heart disease risk factors;…

Analysis of metabolic energy utilization in the Skylab astronauts

NASA Technical Reports Server (NTRS)

Leonard, J. I.

1977-01-01

Skylab biomedical data regarding man's metabolic processes for extended periods of weightlessness is presented. The data was used in an integrated metabolic balance analysis which included analysis of Skylab water balance, electrolyte balance, evaporative water loss, and body composition. A theoretical analysis of energy utilization in man is presented. The results of the analysis are presented in tabular and graphic format.

Metabolic control analysis of integrated energy metabolism in permeabilized cardiomyocytes - experimental study.

PubMed

Tepp, Kersti; Timohhina, Natalja; Chekulayev, Vladimir; Shevchuk, Igor; Kaambre, Tuuli; Saks, Valdur

2010-01-01

The main focus of this research was to apply Metabolic Control Analysis to quantitative investigation of the regulation of respiration by components of the Mitochondrial Interactosome (MI, a supercomplex consisting of ATP Synthasome, mitochondrial creatine kinase (MtCK), voltage dependent anion channel (VDAC), and tubulin) in permeabilized cardiomyocytes. Flux control coefficients (FCC) were measured using two protocols: 1) with direct ADP activation, and 2) with MtCK activation by creatine (Cr) in the presence of ATP and pyruvate kinase-phosphoenolpyruvate system. The results show that the metabolic control is much stronger in the latter case: the sum of the measured FCC is 2.7 versus 0.74 (ADP activation). This is consistent with previous data showing recycling of ADP and ATP inside the MI due to the functional coupling between MtCK and ANT and limited permeability of VDAC for these compounds, PCr being the major energy carrier between the mitochondria and ATPases. In physiological conditions, when the MI is activated, the key sites of regulation of respiration in mitochondria are MtCK (FCC = 0.93), adenine nucleotide translocase ANT (FCC = 0.95) and CoQ cytochrome c oxidoreductase (FCC = 0.4). These results show clearly that under the physiological conditions the energy transfer from mitochondria to the cytoplasm is regulated by the MI supercomplex and is very sensitive to metabolic signals.

Microbial metabolism of tholin

NASA Astrophysics Data System (ADS)

Stoker, C. R.; Boston, P. J.; Mancinelli, R. L.; Segal, W.; Khare, B. N.; Sagan, C.

1990-05-01

In this paper, we show that a wide variety of common soil bacteria are able to obtain their carbon and energy needs from tholin (a class of complex organic heteropolymers thought to be widely distributed through the solar system; in this case tholin was produced by passage of electrical discharge through a mixture of methane, ammonia, and water vapor). We have isolated aerobic, anaerobic, and facultatively anaerobic bacteria which are able to use tholin as a sole carbon source. Organisms which metabolize tholin represent a variety of bacterial genera including Clostridium, Pseudomonas, Bacillus, Acinetobacter, Paracoccus, Alcaligenes, Micrococcus, Cornebacterium, Aerobacter, Arthrobacter, Flavobacterium,and Actinomyces. Aerobic tholin-using bacteria were firrst isolated from soils containing unusual or sparse carbon sources. Some of these organisms were found to be facultatively anaerobic. Strictly anaerobic tholin-using bacteria were isolated from both carbon-rich and carbon-poor anaerobic lake muds. In addition, both aerobic and anaerobic tholin-using bacteria were isolated from common soil collected outside the laboratory building. Some, but not all, of the strains that were able to obtain carbon from tholin were also able to obtain their nitrogen requirements from tholin. Bacteria isolated from common soils were tested for their ability to obtain carbon from the water-soluble fraction, the ethanol-soluble fraction, and the water/ethanol-insoluble fraction of the tholin. Of the 3.5 × 10 7 bacteria isolated per gram of common soils, 1.7 0.5, and 0.2%, respectively, were able to obtaib their carbon requirements from the water-soluble fraction, the ethanol-soluble fraction and the water/ethanol-insoluble fraction of the tholin. The palatability of tholins to modern microbes may have implications for the early evolution of microbial life on Earth. Tholins may have formed the base of the food chain for an early heterotrophic biosphere before the evolution of

A pocket-sized metabolic analyzer for assessment of resting energy expenditure.

PubMed

Zhao, Di; Xian, Xiaojun; Terrera, Mirna; Krishnan, Ranganath; Miller, Dylan; Bridgeman, Devon; Tao, Kevin; Zhang, Lihua; Tsow, Francis; Forzani, Erica S; Tao, Nongjian

2014-04-01

The assessment of metabolic parameters related to energy expenditure has a proven value for weight management; however these measurements remain too difficult and costly for monitoring individuals at home. The objective of this study is to evaluate the accuracy of a new pocket-sized metabolic analyzer device for assessing energy expenditure at rest (REE) and during sedentary activities (EE). The new device performs indirect calorimetry by measuring an individual's oxygen consumption (VO2) and carbon dioxide production (VCO2) rates, which allows the determination of resting- and sedentary activity-related energy expenditure. VO2 and VCO2 values of 17 volunteer adult subjects were measured during resting and sedentary activities in order to compare the metabolic analyzer with the Douglas bag method. The Douglas bag method is considered the Gold Standard method for indirect calorimetry. Metabolic parameters of VO2, VCO2, and energy expenditure were compared using linear regression analysis, paired t-tests, and Bland-Altman plots. Linear regression analysis of measured VO2 and VCO2 values, as well as calculated energy expenditure assessed with the new analyzer and Douglas bag method, had the following linear regression parameters (linear regression slope LRS0, and R-squared coefficient, r(2)) with p = 0: LRS0 (SD) = 1.00 (0.01), r(2) = 0.9933 for VO2; LRS0 (SD) = 1.00 (0.01), r(2) = 0.9929 for VCO2; and LRS0 (SD) = 1.00 (0.01), r(2) = 0.9942 for energy expenditure. In addition, results from paired t-tests did not show statistical significant difference between the methods with a significance level of α = 0.05 for VO2, VCO2, REE, and EE. Furthermore, the Bland-Altman plot for REE showed good agreement between methods with 100% of the results within ±2SD, which was equivalent to ≤10% error. The findings demonstrate that the new pocket-sized metabolic analyzer device is accurate for determining VO2, VCO2, and energy expenditure. Copyright © 2013 Elsevier Ltd and

Rhodanese Functions as Sulfur Supplier for Key Enzymes in Sulfur Energy Metabolism

PubMed Central

Aussignargues, Clément; Giuliani, Marie-Cécile; Infossi, Pascale; Lojou, Elisabeth; Guiral, Marianne; Giudici-Orticoni, Marie-Thérèse; Ilbert, Marianne

2012-01-01

How microorganisms obtain energy is a challenging topic, and there have been numerous studies on the mechanisms involved. Here, we focus on the energy substrate traffic in the hyperthermophilic bacterium Aquifex aeolicus. This bacterium can use insoluble sulfur as an energy substrate and has an intricate sulfur energy metabolism involving several sulfur-reducing and -oxidizing supercomplexes and enzymes. We demonstrate that the cytoplasmic rhodanese SbdP participates in this sulfur energy metabolism. Rhodaneses are a widespread family of proteins known to transfer sulfur atoms. We show that SbdP has also some unusual characteristics compared with other rhodaneses; it can load a long sulfur chain, and it can interact with more than one partner. Its partners (sulfur reductase and sulfur oxygenase reductase) are key enzymes of the sulfur energy metabolism of A. aeolicus and share the capacity to use long sulfur chains as substrate. We demonstrate a positive effect of SbdP, once loaded with sulfur chains, on sulfur reductase activity, most likely by optimizing substrate uptake. Taken together, these results lead us to propose a physiological role for SbdP as a carrier and sulfur chain donor to these key enzymes, therefore enabling channeling of sulfur substrate in the cell as well as greater efficiency of the sulfur energy metabolism of A. aeolicus. PMID:22496367

Transcriptome and metabolome responses of Shewanella oneidensis MR-1 to methyl orange under microaerophilic and aerobic conditions.

PubMed

Cao, Xinhua; Qi, Yueling; Xu, Chen; Yang, Yuyi; Wang, Jun

2017-04-01

Shewanella oneidensis MR-1 degrades various azo dyes under microaerophilic and anaerobic conditions, but this process is inhibited under aerobic conditions. The mechanisms underlying azo dye biodegradation and inhibition remain unknown. Therefore, we investigated metabolic and transcriptional changes in strain MR-1, which was cultured under different conditions, to elucidate these mechanisms. At the transcriptional level, genes involved in certain metabolic processes, particularly the tricarboxylic acid (TCA) cycle, amino acid biodegradation, and the electron transfer system, were significantly altered (M ≧ 2, p > 0.8 ) in the presence of methyl orange (MO). Moreover, a high concentration of dissolved oxygen heavily impacted the expression levels of genes involved in fatty acid biodegradation. Metabolome analysis revealed significant alteration (p < 0.05) in the concentrations of nine metabolites when strain MR-1 was cultured under aerobic conditions; the majority of these metabolites were closely associated with amino acid metabolism and DNA replication. Accordingly, we propose a possible pathway for MO biodegradation and discuss the most likely causes of biodegradation inhibition due to dissolved oxygen.

Characteristics of aerobic granules grown on glucose and acetate in sequential aerobic sludge blanket reactors.

PubMed

Tay, J H; Liu, Q S; Liu, Y

2002-08-01

Aerobic granules were cultivated in two column-type sequential aerobic sludge blanket reactors fed with glucose and acetate, respectively. The characteristics of aerobic granules were investigated. Results indicated that the glucose- and acetate-fed granules have comparable characteristics in terms of settling velocity, size, shape, biomass density, hydrophobicity, physical strength, microbial activity and storage stability. Substrate component does not seem to be a key factor on the formation of aerobic granules. However, microbial diversity of the granules is closely associated with the carbon sources supplied to the reactors. Compared with the conventional activated sludge flocs, aerobic granules exhibit excellent physical characteristics that would be essential for industrial application. This research provides a complete set of characteristics data of aerobic granules grown on glucose and acetate, which would be useful for further development of aerobic granules-based compact bioreactor for handling high strength organic wastewater.

Energy metabolism in mobile, wild-sampled sharks inferred by plasma lipids.

PubMed

Gallagher, Austin J; Skubel, Rachel A; Pethybridge, Heidi R; Hammerschlag, Neil

2017-01-01

Evaluating how predators metabolize energy is increasingly useful for conservation physiology, as it can provide information on their current nutritional condition. However, obtaining metabolic information from mobile marine predators is inherently challenging owing to their relative rarity, cryptic nature and often wide-ranging underwater movements. Here, we investigate aspects of energy metabolism in four free-ranging shark species ( n  = 281; blacktip, bull, nurse, and tiger) by measuring three metabolic parameters [plasma triglycerides (TAG), free fatty acids (FFA) and cholesterol (CHOL)] via non-lethal biopsy sampling. Plasma TAG, FFA and total CHOL concentrations (in millimoles per litre) varied inter-specifically and with season, year, and shark length varied within a species. The TAG were highest in the plasma of less active species (nurse and tiger sharks), whereas FFA were highest among species with relatively high energetic demands (blacktip and bull sharks), and CHOL concentrations were highest in bull sharks. Although temporal patterns in all metabolites were varied among species, there appeared to be peaks in the spring and summer, with ratios of TAG/CHOL (a proxy for condition) in all species displaying a notable peak in summer. These results provide baseline information of energy metabolism in large sharks and are an important step in understanding how the metabolic parameters can be assessed through non-lethal sampling in the future. In particular, this study emphasizes the importance of accounting for intra-specific and temporal variability in sampling designs seeking to monitor the nutritional condition and metabolic responses of shark populations.

Energy metabolism in mobile, wild-sampled sharks inferred by plasma lipids

PubMed Central

Skubel, Rachel A.; Pethybridge, Heidi R.; Hammerschlag, Neil

2017-01-01

Abstract Evaluating how predators metabolize energy is increasingly useful for conservation physiology, as it can provide information on their current nutritional condition. However, obtaining metabolic information from mobile marine predators is inherently challenging owing to their relative rarity, cryptic nature and often wide-ranging underwater movements. Here, we investigate aspects of energy metabolism in four free-ranging shark species (n = 281; blacktip, bull, nurse, and tiger) by measuring three metabolic parameters [plasma triglycerides (TAG), free fatty acids (FFA) and cholesterol (CHOL)] via non-lethal biopsy sampling. Plasma TAG, FFA and total CHOL concentrations (in millimoles per litre) varied inter-specifically and with season, year, and shark length varied within a species. The TAG were highest in the plasma of less active species (nurse and tiger sharks), whereas FFA were highest among species with relatively high energetic demands (blacktip and bull sharks), and CHOL concentrations were highest in bull sharks. Although temporal patterns in all metabolites were varied among species, there appeared to be peaks in the spring and summer, with ratios of TAG/CHOL (a proxy for condition) in all species displaying a notable peak in summer. These results provide baseline information of energy metabolism in large sharks and are an important step in understanding how the metabolic parameters can be assessed through non-lethal sampling in the future. In particular, this study emphasizes the importance of accounting for intra-specific and temporal variability in sampling designs seeking to monitor the nutritional condition and metabolic responses of shark populations. PMID:28852506

Extra-metabolic energy use and the rise in human hyper-density

NASA Astrophysics Data System (ADS)

Burger, Joseph R.; Weinberger, Vanessa P.; Marquet, Pablo A.

2017-03-01

Humans, like all organisms, are subject to fundamental biophysical laws. Van Valen predicted that, because of zero-sum dynamics, all populations of all species in a given environment flux the same amount of energy on average. Damuth’s ’energetic equivalence rule’ supported Van Valen´s conjecture by showing a tradeoff between few big animals per area with high individual metabolic rates compared to abundant small species with low energy requirements. We use metabolic scaling theory to compare variation in densities and individual energy use in human societies to other land mammals. We show that hunter-gatherers occurred at densities lower than the average for a mammal of our size. Most modern humans, in contrast, concentrate in large cities at densities up to four orders of magnitude greater than hunter-gatherers, yet consume up to two orders of magnitude more energy per capita. Today, cities across the globe flux greater energy than net primary productivity on a per area basis. This is possible by importing enormous amounts of energy and materials required to sustain hyper-dense, modern humans. The metabolic rift with nature created by modern cities fueled largely by fossil energy poses formidable challenges for establishing a sustainable relationship on a rapidly urbanizing, yet finite planet.

Extra-metabolic energy use and the rise in human hyper-density.

PubMed

Burger, Joseph R; Weinberger, Vanessa P; Marquet, Pablo A

2017-03-02

Humans, like all organisms, are subject to fundamental biophysical laws. Van Valen predicted that, because of zero-sum dynamics, all populations of all species in a given environment flux the same amount of energy on average. Damuth's 'energetic equivalence rule' supported Van Valen´s conjecture by showing a tradeoff between few big animals per area with high individual metabolic rates compared to abundant small species with low energy requirements. We use metabolic scaling theory to compare variation in densities and individual energy use in human societies to other land mammals. We show that hunter-gatherers occurred at densities lower than the average for a mammal of our size. Most modern humans, in contrast, concentrate in large cities at densities up to four orders of magnitude greater than hunter-gatherers, yet consume up to two orders of magnitude more energy per capita. Today, cities across the globe flux greater energy than net primary productivity on a per area basis. This is possible by importing enormous amounts of energy and materials required to sustain hyper-dense, modern humans. The metabolic rift with nature created by modern cities fueled largely by fossil energy poses formidable challenges for establishing a sustainable relationship on a rapidly urbanizing, yet finite planet.

Functions of Two Types of NADH Oxidases in Energy Metabolism and Oxidative Stress of Streptococcus mutans

PubMed Central

Higuchi, Masako; Yamamoto, Yuji; Poole, Leslie B.; Shimada, Mamoru; Sato, Yutaka; Takahashi, Nobuhiro; Kamio, Yoshiyuki

1999-01-01

We have previously identified two distinct NADH oxidases corresponding to H2O2-forming oxidase (Nox-1) and H2O-forming oxidase (Nox-2) induced in Streptococcus mutans. Sequence analyses indicated a strong similarity between Nox-1 and AhpF, the flavoprotein component of Salmonella typhimurium alkyl hydroperoxide reductase; an open reading frame upstream of nox-1 also showed homology to AhpC, the direct peroxide-reducing component of S. typhimurium alkyl hydroperoxide reductase. To determine their physiological functions in S. mutans, we constructed knockout mutants of Nox-1, Nox-2, and/or the AhpC homologue; we verified that Nox-2 plays an important role in energy metabolism through the regeneration of NAD+ but Nox-1 contributes negligibly. The Nox-2 mutant exhibited greatly reduced aerobic growth on mannitol, whereas there was no significant effect of aerobiosis on the growth on mannitol of the other strains or growth on glucose of any of the strains. Although the Nox-2 mutants grew well on glucose aerobically, the end products of glucose fermentation by the Nox-2 mutant were substantially shifted to higher ratios of lactic acid to acetic acid compared with wild-type cells. The resistance to cumene hydroperoxide of Escherichia coli TA4315 (ahpCF-defective mutant) transformed with pAN119 containing both nox-1 and ahpC genes was not only restored but enhanced relative to that of E. coli K-12 (parent strain), indicating a clear function for Nox-1 as part of an alkyl hydroperoxide reductase system in vivo in combination with AhpC. Surprisingly, the Nox-1 and/or AhpC deficiency had no effect on the sensitivity of S. mutans to cumene hydroperoxide and H2O2, implying that the existence of some other antioxidant system(s) independent of Nox-1 in S. mutans compensates for the deficiency. PMID:10498705

AMPK Is Essential to Balance Glycolysis and Mitochondrial Metabolism to Control T-ALL Cell Stress and Survival.

PubMed

Kishton, Rigel J; Barnes, Carson E; Nichols, Amanda G; Cohen, Sivan; Gerriets, Valerie A; Siska, Peter J; Macintyre, Andrew N; Goraksha-Hicks, Pankuri; de Cubas, Aguirre A; Liu, Tingyu; Warmoes, Marc O; Abel, E Dale; Yeoh, Allen Eng Juh; Gershon, Timothy R; Rathmell, W Kimryn; Richards, Kristy L; Locasale, Jason W; Rathmell, Jeffrey C

2016-04-12

T cell acute lymphoblastic leukemia (T-ALL) is an aggressive malignancy associated with Notch pathway mutations. While both normal activated and leukemic T cells can utilize aerobic glycolysis to support proliferation, it is unclear to what extent these cell populations are metabolically similar and if differences reveal T-ALL vulnerabilities. Here we show that aerobic glycolysis is surprisingly less active in T-ALL cells than proliferating normal T cells and that T-ALL cells are metabolically distinct. Oncogenic Notch promoted glycolysis but also induced metabolic stress that activated 5' AMP-activated kinase (AMPK). Unlike stimulated T cells, AMPK actively restrained aerobic glycolysis in T-ALL cells through inhibition of mTORC1 while promoting oxidative metabolism and mitochondrial Complex I activity. Importantly, AMPK deficiency or inhibition of Complex I led to T-ALL cell death and reduced disease burden. Thus, AMPK simultaneously inhibits anabolic growth signaling and is essential to promote mitochondrial pathways that mitigate metabolic stress and apoptosis in T-ALL. Copyright © 2016 Elsevier Inc. All rights reserved.

Effect of hemoglobin and immunization status on energy metabolism of weanling pigs.

PubMed

Gentry, J L; Swinkels, J W; Lindemann, M D; Schrama, J W

1997-04-01

We investigated the effect of (Hb) and immunization status on energy metabolism of newly weaned pigs. An additional focus of the study was to determine the development of circadian rhythms as evidenced by heat production patterns. Twenty-four 4-wk-old crossbred weanling barrows were placed into groups of three based on weight and litter origin, and the groups were allotted to one of four treatments. Treatments were arranged as a 2 x 2 factorial. The factors included 1) Hb status (low vs high) and 2) immunization status (antigen vs placebo). Hemoglobin status was obtained by injecting 3-d-old barrows with 100 (low) or 200 mg (high) of Fe. At 4 wk, initial blood Hb concentrations were 6.0 mM for the low group and 7.8 mM for the high group. Energy metabolism was measured using two weekly total energy and nitrogen balance collections. Energy intake and retention were higher (P < .05) in pigs with a high Hb level. Energy metabolism was not affected (P > .10) by immunization status, and heat production was not affected (P > .10) by either Hb or immunization status. Total heat production (HTOT) increased (P < .001) daily and reflected a daily increase (P < .001) in activity (HACT) and activity-free (HCOR) heat production. An increase (P < .001) in HTOT and HACT was detected for the light period compared with the dark period over the total experimental period but a decrease (P < .001) in HCOR was detected; however, HACT for the dark period was approximately half of that measured during the light period. In conclusion, Hb status affected energy metabolism; pigs having a high Hb status had a higher energy retention. Immunization status had minimal effects on energy metabolism and heat production. Additionally, the diurnal circadian rhythm seen in older pigs had not been established by 2 wk after weaning.

[Energy power in mountains: difference in metabolism pattern results in different adaption traits in Tibetans].

PubMed

Bai, Zhen-Zhong; Jin, Guo-En; Wu-Ren, Tana; Ga, Qin; Ge, Ri-Li

2012-11-01

Energy metabolism plays an important role in life survival for species living in high altitude hypoxia condition. Air-breathing organisms require oxygen to create energy. Tibetans are the well-adapted highlanders in Qinghai-Tibetan Plateau. It was thought that different metabolic approaches could lead to different adaptation traits to high altitude hypoxia. Recently identified hypoxia inducible factors pathway regulators, endothelial PAS domain protein1 (EPAS1)/HIF-2a and PPARA, were involved in decreasing hemoglobin concentrations in Tibetans. Because EPAS1 and PPARA also modulated the energy metabolism during hypoxia, we hypothesized that positive selected EPAS1 and PPARA genes were also involved in unique energy metabolisms in Tibetans. In this brief review, we take a look into genetic determinations to energy metabolisms for hypoxia adaptations traits in Tibetans and mal-adaptive conditions such as high altitude diseases.

The energy production of juvenile Arenicola marina (Polychaeta) under anoxic and hypoxic conditions

NASA Astrophysics Data System (ADS)

Schiedek, Doris; Schöttler, Udo

1990-06-01

The mode of anaerobic energy production of juvenile Arenicola marina (0-generation) was investigated under experimental conditions and in the biotope. Under experimental anaerobic conditions, juvenile A. marina produce energy by the pathways known from the adults and other euryoxic invertebrates with succinate and the volatile fatty acids, acetate and propionate, as main end products. However, the juvenile lugworms are less resistent to anoxia than the adults. The reasons for this might be their small glycogen stores and their limited ability to reduce the metabolic rate. Nevertheless, on the tidal flats the juveniles settle particularly in the area next to the high tide line, which offers such extreme conditions that adult lugworms cannot live there. This different behaviour can be explained by the dissimilar ability to use oxygen at very low partial pressures. Juveniles maintain an aerobic energy metabolism even at a PWO 2 of 15 Torr at which adults are forced to produce energy exclusively by the less effective anaerobic mode. In the field, no indications of an anaerobic energy metabolism were detected in juveniles even after an exposure of 8 hours.

Effects of thermal increase on aerobic capacity and swim performance in a tropical inland fish.

PubMed

McDonnell, Laura H; Chapman, Lauren J

2016-09-01

Rising water temperature associated with climate change is increasingly recognized as a potential stressor for aquatic organisms, particularly for tropical ectotherms that are predicted to have narrow thermal windows relative to temperate ectotherms. We used intermittent flow resting and swimming respirometry to test for effects of temperature increase on aerobic capacity and swim performance in the widespread African cichlid Pseudocrenilabrus multicolor victoriae, acclimated for a week to a range of temperatures (2°C increments) between 24 and 34°C. Standard metabolic rate (SMR) increased between 24 and 32°C, but fell sharply at 34°C, suggesting either an acclimatory reorganization of metabolism or metabolic rate depression. Maximum metabolic rate (MMR) was elevated at 28 and 30°C relative to 24°C. Aerobic scope (AS) increased between 24 and 28°C, then declined to a level comparable to 24°C, but increased dramatically 34°C, the latter driven by the drop in SMR in the warmest treatment. Critical swim speed (Ucrit) was highest at intermediate temperature treatments, and was positively related to AS between 24 and 32°C; however, at 34°C, the increase in AS did not correspond to an increase in Ucrit, suggesting a performance cost at the highest temperature. Crown Copyright © 2016. Published by Elsevier Inc. All rights reserved.

Ferrous glycinate regulates cell energy metabolism by restrictinghypoxia-induced factor-1α expression in human A549 cells.

PubMed

Kuo, Yung-Ting; Jheng, Jhong-Huei; Lo, Mei-Chen; Chen, Wei-Lu; Wang, Shyang-Guang; Lee, Horng-Mo

2018-06-04

Iron or oxygen regulates the stability of hypoxia inducible factor-1α (HIF-1α). We investigated whether ferrous glycinate would affect HIF-1α accumulation, aerobic glycolysis and mitochondrial energy metabolism in human A549 lung cancer cells. Incubation of A549 cells with ferrous glycinate decreased the protein levels of HIF-1α, which was abrogated by proteosome inhibitor, or prolyl hydroxylase inhibitor. The addition of ferrous glycinate decreased protein levels of glucose transporter-1, hexokinase-2, and lactate dehydrogenase A, and decreased pyruvate dehydrogenase kinase-1 (PDK-1) and pyruvate dehydrogenase (PDH) phosphorylation in A549 cells. Ferrous glycinate also increased the expression of the mitochondrial transcription factor A (TFAM), and the mitochondrial protein, cytochrome c oxidase (COX-IV). Silencing of HIF-1α expression mimicked the effects of ferrous glycinate on PDK-1, PDH, TFAM and COX-IV in A549 cells. Ferrous glycinate increased mitochondrial membrane potential and ATP production in A549 cells. These results suggest that ferrous glycinate may reverse Warburg effect through down regulating HIF-1α in A549 cells.

Physiology of leptin: energy homeostasis, neuroendocrine function and metabolism

PubMed Central

Park, Hyeong-Kyu; Ahima, Rexford S.

2014-01-01

Leptin is secreted by adipose tissue and regulates energy homeostasis, neuroendocrine function, metabolism, immune function and other systems through its effects on the central nervous system and peripheral tissues. Leptin administration has been shown to restore metabolic and neuroendocrine abnormalities in individuals with leptin-deficient states, including hypothalamic amenorrhea and lipoatrophy. In contrast, obese individuals are resistant to leptin. Recombinant leptin is beneficial in patients with congenital leptin deficiency or generalized lipodystrophy. However, further research on molecular mediators of leptin resistance is needed for the development of targeted leptin sensitizing therapies for obesity and related metabolic diseases. PMID:25199978

Combined anaerobic/aerobic digestion: effect of aerobic retention time on nitrogen and solids removal.

PubMed

Kim, Jongmin; Novak, John T

2011-09-01

A combined anaerobic/aerobic sludge digestion system was studied to determine the effect of aerobic solids retention time (SRT) on its solids and nitrogen removal efficiencies. After the anaerobic digester reached steady state, effluent from the anaerobic digester was fed to aerobic digesters that were operated at 2- to 5-day SRTs. The anaerobic system was fed with a mixture of primary and secondary sludge from a local municipal wastewater treatment plant. Both systems were fed once per a day. The aerobic reactor was continuously aerated with ambient air, maintaining dissolved oxygen level at 1.1 +/- 0.3 mg/L. At a 4-day or longer SRT, more than 11% additional volatile solids and 90% or greater ammonia were removed in the aerobic digester, while 32.8 mg-N/L or more nitrite/nitrate also was measured. Most total Kjeldahl nitrogen removal was via ammonia removal, while little organic nitrogen was removed in the aerobic digester.

TOP1MT deficiency promotes GC invasion and migration via the enhancements of LDHA expression and aerobic glycolysis.

PubMed

Wang, Hongqiang; Zhou, Rui; Sun, Li; Xia, Jianling; Yang, Xuchun; Pan, Changqie; Huang, Na; Shi, Min; Bin, Jianping; Liao, Yulin; Liao, Wangjun

2017-11-01

Aerobic glycolysis plays an important role in cancer progression. New target genes regulating cancer aerobic glycolysis must be explored to improve patient prognosis. Mitochondrial topoisomerase I ( TOP1MT ) deficiency suppresses glucose oxidative metabolism but enhances glycolysis in normal cells. Here, we examined the role of TOP1MT in gastric cancer (GC) and attempted to determine the underlying mechanism. Using in vitro and in vivo experiments and analyzing the clinicopathological characteristics of patients with GC, we found that TOP1MT expression was lower in GC samples than in adjacent nonmalignant tissues. TOP1MT knockdown significantly promoted GC migration and invasion in vitro and in vivo Importantly, TOP1MT silencing increased glucose consumption, lactate production, glucose transporter 1 expression and the epithelial-mesenchymal transition (EMT) in GC. Additionally, regulation of glucose metabolism induced by TOP1MT was significantly associated with lactate dehydrogenase A (LDHA) expression. A retrospective analysis of clinical data from 295 patients with GC demonstrated that low TOP1MT expression was associated with lymph node metastasis, recurrence and high mortality rates. TOP1MT deficiency enhanced glucose aerobic glycolysis by stimulating LDHA to promote GC progression. © 2017 The authors.

Transcriptome dynamics during the transition from anaerobic photosynthesis to aerobic respiration in Rhodobacter sphaeroides 2.4.1.

PubMed

Arai, Hiroyuki; Roh, Jung Hyeob; Kaplan, Samuel

2008-01-01

Rhodobacter sphaeroides 2.4.1 is a facultative photosynthetic anaerobe that grows by anoxygenic photosynthesis under anaerobic-light conditions. Changes in energy generation pathways under photosynthetic and aerobic respiratory conditions are primarily controlled by oxygen tensions. In this study, we performed time series microarray analyses to investigate transcriptome dynamics during the transition from anaerobic photosynthesis to aerobic respiration. Major changes in gene expression profiles occurred in the initial 15 min after the shift from anaerobic-light to aerobic-dark conditions, with changes continuing to occur up to 4 hours postshift. Those genes whose expression levels changed significantly during the time series were grouped into three major classes by clustering analysis. Class I contained genes, such as that for the aa3 cytochrome oxidase, whose expression levels increased after the shift. Class II contained genes, such as those for the photosynthetic apparatus and Calvin cycle enzymes, whose expression levels decreased after the shift. Class III contained genes whose expression levels temporarily increased during the time series. Many genes for metabolism and transport of carbohydrates or lipids were significantly induced early during the transition, suggesting that those endogenous compounds were initially utilized as carbon sources. Oxidation of those compounds might also be required for maintenance of redox homeostasis after exposure to oxygen. Genes for the repair of protein and sulfur groups and uptake of ferric iron were temporarily upregulated soon after the shift, suggesting they were involved in a response to oxidative stress. The flagellar-biosynthesis genes were expressed in a hierarchical manner at 15 to 60 min after the shift. Numerous transporters were induced at various time points, suggesting that the cellular composition went through significant changes during the transition from anaerobic photosynthesis to aerobic respiration

Acid azo dye remediation in anoxic-aerobic-anoxic microenvironment under periodic discontinuous batch operation: bio-electro kinetics and microbial inventory.

PubMed

Venkata Mohan, S; Suresh Babu, P; Naresh, K; Velvizhi, G; Madamwar, Datta

2012-09-01

Functional behavior of anoxic-aerobic-anoxic microenvironment on azo dye (C.I. Acid black 10B) degradation was evaluated in a periodic discontinuous batch mode operation for 26 cycles. Dye removal efficiency and azo-reductase activity (30.50 ± 1 U) increased with each feeding event until 13th cycle and further stabilized. Dehydrogenase activity also increased gradually and stabilized (2.0 ± 0.2 μg/ml) indicating the stable proton shuttling between metabolic intermediates providing higher number of reducing equivalents towards dye degradation. Voltammetric profiles showed drop in redox catalytic currents during stabilized phase also supports the consumption of reducing equivalents towards dye removal. Change in Tafel slopes, polarization resistance and other bioprocess parameters correlated well with the observed dye removal and biocatalyst behavior. Microbial community analysis documented the involvement of specific organism pertaining to aerobic and facultative functions with heterotrophic and autotrophic metabolism. Integrating anoxic microenvironment with aerobic operation might have facilitated effective dye mineralization due to the possibility of combining redox functions. Copyright © 2012 Elsevier Ltd. All rights reserved.

Water-energy links in cities: the urban metabolism of London

NASA Astrophysics Data System (ADS)

Mijic, A.; Ruiz Cazorla, J.; Keirstead, J.

2014-12-01

Rapid urbanisation results in increased water consumption in cities, requiring improved tools for understanding adaptive measures for water resources management under climate change. The energy sector is facing the same challenges and requires equally comprehensive solutions. More frequent water shortages due to climate and land use changes and potential limits on CO2 emissions from fossil fuels that science demands indicate clearly that the next step in the sustainable city development will be to look for the most efficient use of these highly interdependent resources. One of the concepts that could be used for quantifying fundamental flows in an urban environment such as water and energy is the urban metabolism framework. This paper will examine the concept of urban metabolism by quantifying amounts and trends of water and energy consumed in London by four main sectors: residential, industrial, commercial and public. Key data requirements at the sector level will be identified and initial mapping of critical factors for urban sustainability will be provided. Finally, the work will examine the potential of urban metabolism framework to provide data and information for implementing water, energy and greenhouse emissions trade-off 'fit-for-purpose' strategy for water supply security. The paper is a part of the Panta Rhei Research Initiative of the International Association of Hydrological Sciences (IAHS) under the working group of Energy and Food Impacts on Water.

Energy and greenhouse gas life cycle assessment and cost analysis of aerobic and anaerobic membrane bioreactor systems: Influence of scale, population density, climate, and methane recovery

EPA Science Inventory

This study calculated the energy and greenhouse gas life cycle and cost profiles of transitional aerobic membrane bioreactors (AeMBR) and anaerobic membrane bioreactors (AnMBR). Membrane bioreactors (MBR) represent a promising technology for decentralized wastewater treatment and...

The gut microbiota modulates host energy and lipid metabolism in mice[S

PubMed Central

Velagapudi, Vidya R.; Hezaveh, Rahil; Reigstad, Christopher S.; Gopalacharyulu, Peddinti; Yetukuri, Laxman; Islam, Sama; Felin, Jenny; Perkins, Rosie; Borén, Jan; Orešič, Matej; Bäckhed, Fredrik

2010-01-01

The gut microbiota has recently been identified as an environmental factor that may promote metabolic diseases. To investigate the effect of gut microbiota on host energy and lipid metabolism, we compared the serum metabolome and the lipidomes of serum, adipose tissue, and liver of conventionally raised (CONV-R) and germ-free mice. The serum metabolome of CONV-R mice was characterized by increased levels of energy metabolites, e.g., pyruvic acid, citric acid, fumaric acid, and malic acid, while levels of cholesterol and fatty acids were reduced. We also showed that the microbiota modified a number of lipid species in the serum, adipose tissue, and liver, with its greatest effect on triglyceride and phosphatidylcholine species. Triglyceride levels were lower in serum but higher in adipose tissue and liver of CONV-R mice, consistent with increased lipid clearance. Our findings show that the gut microbiota affects both host energy and lipid metabolism and highlights its role in the development of metabolic diseases. PMID:20040631

Elevated temperature and acclimation time affect metabolic performance in the heavily exploited Nile perch of Lake Victoria.

PubMed

Nyboer, Elizabeth A; Chapman, Lauren J

2017-10-15

Increasing water temperatures owing to anthropogenic climate change are predicted to negatively impact the aerobic metabolic performance of aquatic ectotherms. Specifically, it has been hypothesized that thermal increases result in reductions in aerobic scope (AS), which lead to decreases in energy available for essential fitness and performance functions. Consequences of warming are anticipated to be especially severe for warm-adapted tropical species as they are thought to have narrow thermal windows and limited plasticity for coping with elevated temperatures. In this study we test how predicted warming may affect the aerobic performance of Nile perch ( Lates niloticus ), a commercially harvested fish species in the Lake Victoria basin of East Africa. We measured critical thermal maxima (CT max ) and key metabolic variables such as AS and excess post-exercise oxygen consumption (EPOC) across a range of temperatures, and compared responses between acute (3-day) exposures and 3-week acclimations. CT max increased with acclimation temperature; however, 3-week-acclimated fish had higher overall CT max than acutely exposed individuals. Nile perch also showed the capacity to increase or maintain high AS even at temperatures well beyond their current range; however, acclimated Nile perch had lower AS compared with acutely exposed fish. These changes were accompanied by lower EPOC, suggesting that drops in AS may reflect improved energy utilization after acclimation, a finding that is supported by improvements in growth at high temperatures over the acclimation period. Overall, the results challenge predictions that tropical species have limited thermal plasticity, and that high temperatures will be detrimental because of limitations in AS. © 2017. Published by The Company of Biologists Ltd.

Analysis of the assessment of caloric expenditure in four modes of aerobic dance.

PubMed

Rixon, Kendall P; Rehor, Peter R; Bemben, Michael G

2006-08-01

Aerobic dance has been purported to help with weight management; however, it is not known if various forms of dance are as effective as traditional modalities. This study estimated energy expenditure by heart rate for 28 women participating in 4 modes of aerobic dance (Bodycombat [i.e., TAEBO]; Pump; Step; and RPM [i.e., spinning]) compared to 2 running speeds. Pump had significantly (p < 0.01) lower energy expenditure (8.0 +/- 1.6 kcal.min(-1)) compared to the other classes (RPM: 9.9 +/- 1.9 kcal.min(-1); Step: 9.6 +/- 1.8 kcal.min(-1); and Bodycombat: 9.7 +/- 2.0 kcal.min(-1)) and running at 8.05 km.h(-1) (9.16 +/- 1.53 kcal.min(-1)). Also, Step (p < 0.01), Bodycombat (p < 0.01), and RPM (p < 0.01) had significantly higher caloric expenditures than running at 8.05 km.h(-1) but significantly lower than running at 8.37 km.h(-1) (10.30 +/- 1.72 kcal.min(-1)). In conclusion, RPM, Bodycombat, and Step aerobics were equally as effective as jogging between 8.05 and 8.37 km.h(-1), and they met American College of Sports Medicine guidelines for weight modification and maintenance. Additionally, heart rate assessment provided a quantitative method for estimating energy expenditure and the effectiveness of different aerobic programs.

Adverse metabolic risk profiles in Greenlandic Inuit children compared to Danish children.

PubMed

Munch-Andersen, T; Sorensen, K; Andersen, L B; Aachmann-Andersen, N J; Aksglaede, L; Juul, A; Helge, J W

2013-06-01

During recent decades, the prevalence of metabolic morbidity has increased rapidly in adult Greenlandic Inuit. To what extent this is also reflected in the juvenile Inuit population is unknown. The objective was, therefore, in the comparison with Danish children, to evaluate metabolic profiles in Greenlandic Inuit children from the capital in the southern and from the northern most villages 187 Inuit and 132 Danish children were examined with anthropometrics, pubertal staging, fasting blood samples, and a maximal aerobic test. Both Inuit children living in Nuuk and the northern villages had significantly higher glucose, total cholesterol, apolipoprotein A1 levels, and diastolic blood pressure compared with Danish children after adjustment for differences in adiposity and aerobic fitness levels. The Inuit children living in Nuuk had significantly higher BMI, body fat %, HbA1 c, and significantly lower aerobic fitness and ApoA1 levels than northern living Inuit children. Greenlandic Inuit children had adverse metabolic health profile compared to the Danish children, the differences where more pronounced in Inuit children living in Nuuk. The tendencies toward higher prevalence of diabetes and metabolic morbidity in the adult Greenlandic Inuit population may also be present in the Inuit children population. Copyright © 2013 The Obesity Society.