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Sample records for aerobic metabolic rates

  1. Metabolomics of aerobic metabolism in mice selected for increased maximal metabolic rate

    PubMed Central

    Wone, Bernard; Donovan, Edward R.; Hayes, Jack P.

    2014-01-01

    Maximal aerobic metabolic rate (MMR) is an important physiological and ecological variable that sets an upper limit to sustained, vigorous activity. How the oxygen cascade from the external environment to the mitochondria may affect MMR has been the subject of much interest, but little is known about the metabolic profiles that underpin variation in MMR. We tested how seven generations of artificial selection for high mass-independent MMR affected metabolite profiles of two skeletal muscles (gastrocnemius and plantaris) and the liver. MMR was 12.3% higher in mass selected for high MMR than in controls. Basal metabolic rate was 3.5% higher in selected mice than in controls. Artificial selection did not lead to detectable changes in the metabolic profiles from plantaris muscle, but in the liver amino acids and tricarboxylic acid cycle (TCA cycle) metabolites were lower in high-MMR mice than in controls. In gastrocnemius, amino acids and TCA cycle metabolites were higher in high-MMR mice than in controls, indicating elevated amino acid and energy metabolism. Moreover, in gastrocnemius free fatty acids and triacylglycerol fatty acids were lower in high-MMR mice than in controls. Because selection for high MMR was associated with changes in the resting metabolic profile of both liver and gastrocnemius, the result suggests a possible mechanistic link between resting metabolism and MMR. In addition, it is well established that diet and exercise affect the composition of fatty acids in muscle. The differences that we found between control lines and lines selected for high MMR demonstrate that the composition of fatty acids in muscle is also affected by genetic factors. PMID:21982590

  2. Rate limiting factors in trichloroethylene co-metabolic degradation by phenol-grown aerobic granules.

    PubMed

    Zhang, Yi; Tay, Joo Hwa

    2014-04-01

    The potential of aerobic granular sludge in co-metabolic removal of recalcitrant substances was evaluated using trichloroethylene (TCE) as the model compound. Aerobic granules cultivated in a sequencing batch reactor with phenol as the growth substrate exhibited TCE and phenol degradation activities lower than previously reported values. Depletion of reducing energy and diffusion limitation within the granules were investigated as the possible rate limiting factors. Sodium formate and citrate were supplied to the granules in batch studies as external electron sources. No significant enhancing effect was observed on the instant TCE transformation rates, but 10 mM formate could improve the ultimate transformation capacity by 26 %. Possible diffusion barrier was studied by sieving the biomass into five size fractions, and determining their specific TCE and phenol degradation rates and capacities. Biomass in the larger size fractions generally showed lower activities. Large granules of >700 μm diameter exhibited only 22 % of the flocs' TCE transformation capacity and 35 % of its phenol dependent SOUR, indicating the possible occurrence of diffusion limitation in larger biomass. However, the highest specific TCE transformation rate was observed with the fraction that mostly consisted of small granules (150-300 μm), suggesting an optimal size range while applying aerobic granules in TCE co-metabolic removal.

  3. Intraspecific variation in aerobic metabolic rate of fish: relations with organ size and enzyme activity in brown trout.

    PubMed

    Norin, Tommy; Malte, Hans

    2012-01-01

    Highly active animals require a high aerobic capacity (i.e., a high maximum metabolic rate [MMR]) to sustain such activity, and it has been speculated that a greater capacity for aerobic performance is reflected in larger organs, which serve as energy processors but are also expensive to maintain and which increase the minimal cost of living (i.e., the basal or standard metabolic rate [SMR]). In this study, we assessed the extent of intraspecific variation in metabolic rate within a group of brown trout (Salmo trutta L.) and tested whether the observed variation in residual (body-mass-corrected) SMR, MMR, and absolute aerobic scope could be explained by variations in the residual size (mass) of metabolically active internal organs. Residual SMR was found to correlate positively with residual MMR, indicating a link between these two metabolic parameters, but no relationship between organ mass and metabolic rate was found for liver, heart, spleen, intestine, or stomach. Instead, activity in the liver of two aerobic mitochondrial enzymes, cytochrome c oxidase and, to a lesser extent, citrate synthase, was found to correlate with whole-animal metabolic rate, indicating that causes for intraspecific variation in the metabolic rate of fish can be found at a lower organizational level than organ size.

  4. The interplay between aerobic metabolism and antipredator performance: vigilance is related to recovery rate after exercise.

    PubMed

    Killen, Shaun S; Reid, Donald; Marras, Stefano; Domenici, Paolo

    2015-01-01

    When attacked by a predator, fish respond with a sudden fast-start motion away from the threat. Although this anaerobically-powered swimming necessitates a recovery phase which is fueled aerobically, little is known about links between escape performance and aerobic traits such as aerobic scope (AS) or recovery time after exhaustive exercise. Slower recovery ability or a reduced AS could make some individuals less likely to engage in a fast-start response or display reduced performance. Conversely, increased vigilance in some individuals could permit faster responses to an attack but also increase energy demand and prolong recovery after anaerobic exercise. We examined how AS and the ability to recover from anaerobic exercise relates to differences in fast-start escape performance in juvenile golden gray mullet at different acclimation temperatures. Individuals were acclimated to either 18, 22, or 26°C, then measured for standard and maximal metabolic rates and AS using intermittent flow respirometry. Anaerobic capacity and the time taken to recover after exercise were also assessed. Each fish was also filmed during a simulated attack to determine response latency, maximum speed and acceleration, and turning rate displayed during the escape response. Across temperatures, individuals with shorter response latencies during a simulated attack are those with the longest recovery time after exhaustive anaerobic exercise. Because a short response latency implies high preparedness to escape, these results highlight the trade-off between the increased vigilance and metabolic demand, which leads to longer recovery times in fast reactors. These results improve our understanding of the intrinsic physiological traits that generate inter-individual variability in escape ability, and emphasize that a full appreciation of trade-offs associated with predator avoidance and energy balance must include energetic costs associated with vigilance and recovery from anaerobic exercise.

  5. The interplay between aerobic metabolism and antipredator performance: vigilance is related to recovery rate after exercise

    PubMed Central

    Killen, Shaun S.; Reid, Donald; Marras, Stefano; Domenici, Paolo

    2015-01-01

    When attacked by a predator, fish respond with a sudden fast-start motion away from the threat. Although this anaerobically-powered swimming necessitates a recovery phase which is fueled aerobically, little is known about links between escape performance and aerobic traits such as aerobic scope (AS) or recovery time after exhaustive exercise. Slower recovery ability or a reduced AS could make some individuals less likely to engage in a fast-start response or display reduced performance. Conversely, increased vigilance in some individuals could permit faster responses to an attack but also increase energy demand and prolong recovery after anaerobic exercise. We examined how AS and the ability to recover from anaerobic exercise relates to differences in fast-start escape performance in juvenile golden gray mullet at different acclimation temperatures. Individuals were acclimated to either 18, 22, or 26°C, then measured for standard and maximal metabolic rates and AS using intermittent flow respirometry. Anaerobic capacity and the time taken to recover after exercise were also assessed. Each fish was also filmed during a simulated attack to determine response latency, maximum speed and acceleration, and turning rate displayed during the escape response. Across temperatures, individuals with shorter response latencies during a simulated attack are those with the longest recovery time after exhaustive anaerobic exercise. Because a short response latency implies high preparedness to escape, these results highlight the trade-off between the increased vigilance and metabolic demand, which leads to longer recovery times in fast reactors. These results improve our understanding of the intrinsic physiological traits that generate inter-individual variability in escape ability, and emphasize that a full appreciation of trade-offs associated with predator avoidance and energy balance must include energetic costs associated with vigilance and recovery from anaerobic exercise

  6. Calorespirometry reveals that goldfish prioritize aerobic metabolism over metabolic rate depression in all but near-anoxic environments.

    PubMed

    Regan, Matthew D; Gill, Ivan S; Richards, Jeffrey G

    2017-02-15

    Metabolic rate depression (MRD) has long been proposed as the key metabolic strategy of hypoxic survival, but surprisingly, the effects of changes in hypoxic O2 tensions (PwO2 ) on MRD are largely unexplored. We simultaneously measured the O2 consumption rate (ṀO2 ) and metabolic heat of goldfish using calorespirometry to test the hypothesis that MRD is employed at hypoxic PwO2  values and initiated just below Pcrit, the PwO2 below which ṀO2  is forced to progressively decline as the fish oxyconforms to decreasing PwO2 Specifically, we used closed-chamber and flow-through calorespirometry together with terminal sampling experiments to examine the effects of PwO2  and time on ṀO2 , metabolic heat and anaerobic metabolism (lactate and ethanol production). The closed-chamber and flow-through experiments yielded slightly different results. Under closed-chamber conditions with a continually decreasing PwO2 , goldfish showed a Pcrit of 3.0±0.3 kPa and metabolic heat production was only depressed at PwO2  between 0 and 0.67 kPa. Under flow-through conditions with PwO2  held at a variety of oxygen tensions for 1 and 4 h, goldfish also initiated MRD between 0 and 0.67 kPa but maintained ṀO2  to 0.67 kPa, indicating that Pcrit is at or below this PwO2 Anaerobic metabolism was strongly activated at PwO2 ≤1.3 kPa, but only used within the first hour at 1.3 and 0.67 kPa, as anaerobic end-products did not accumulate between 1 and 4 h exposure. Taken together, it appears that goldfish reserve MRD for near-anoxia, supporting routine metabolic rate at sub-PcritPwO2  values with the help of anaerobic glycolysis in the closed-chamber experiments, and aerobically after an initial (<1 h) activation of anaerobic metabolism in the flow-through experiments, even at 0.67 kPa PwO2.

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

    PubMed Central

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

    2016-01-01

    [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. PMID:27390411

  8. 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.

  9. Measuring maximum and standard metabolic rates using intermittent-flow respirometry: a student laboratory investigation of aerobic metabolic scope and environmental hypoxia in aquatic breathers.

    PubMed

    Rosewarne, P J; Wilson, J M; Svendsen, J C

    2016-01-01

    Metabolic rate is one of the most widely measured physiological traits in animals and may be influenced by both endogenous (e.g. body mass) and exogenous factors (e.g. oxygen availability and temperature). Standard metabolic rate (SMR) and maximum metabolic rate (MMR) are two fundamental physiological variables providing the floor and ceiling in aerobic energy metabolism. The total amount of energy available between these two variables constitutes the aerobic metabolic scope (AMS). A laboratory exercise aimed at an undergraduate level physiology class, which details the appropriate data acquisition methods and calculations to measure oxygen consumption rates in rainbow trout Oncorhynchus mykiss, is presented here. Specifically, the teaching exercise employs intermittent flow respirometry to measure SMR and MMR, derives AMS from the measurements and demonstrates how AMS is affected by environmental oxygen. Students' results typically reveal a decline in AMS in response to environmental hypoxia. The same techniques can be applied to investigate the influence of other key factors on metabolic rate (e.g. temperature and body mass). Discussion of the results develops students' understanding of the mechanisms underlying these fundamental physiological traits and the influence of exogenous factors. More generally, the teaching exercise outlines essential laboratory concepts in addition to metabolic rate calculations, data acquisition and unit conversions that enhance competency in quantitative analysis and reasoning. Finally, the described procedures are generally applicable to other fish species or aquatic breathers such as crustaceans (e.g. crayfish) and provide an alternative to using higher (or more derived) animals to investigate questions related to metabolic physiology.

  10. The Transition from Aerobic to Anaerobic Metabolism.

    ERIC Educational Resources Information Center

    Skinner, James S.; McLellan, Thomas H.

    1980-01-01

    The transition from aerobic to anaerobic metabolism is discussed. More research is needed on different kinds of athletes and athletic activities and how they may affect aerobic and anaerobic metabolisms. (CJ)

  11. Basal metabolic rate, maximum thermogenic capacity and aerobic scope in rodents: interaction between environmental temperature and torpor use.

    PubMed

    Careau, Vincent

    2013-04-23

    When torpid animals arouse and warm up to restore normal body temperature (T(b)), they produce heat at levels that can reach up to 10 times basal metabolic rate (BMR), close to the cold-induced summit metabolism (VO(2)-sum). Because torpor is an adaptation aimed at conserving energy over periods of low ambient temperature (T(a)) and food availability, selective forces that have led to the evolution of torpor may have simultaneously favoured high thermogenic capacity (i.e. VO(2)-sum) relative to the maintenance costs (i.e. BMR), hence a higher factorial aerobic scope (FAS; the ratio of VO(2)-sum to BMR). My objective was to test this adaptive hypothesis using a phylogenetically informed comparative approach with data on BMR and VO(2)-sum in rodents. I found a strong negative correlation between FAS and the average of the daily minimum T(a) (T(min)) in species using torpor, which was due to differential effects of T(a) on BMR (but not VO(2)-sum) in species that use torpor compared with species that do not. In addition, FAS was negatively correlated with the lowest torpid T(b) in a subset of nine species. These results suggest that in species using torpor, selective forces may have acted to maximize the efficiency of thermogenic capacity (VO(2)-sum) relative to maintenance costs (BMR), resulting in an increasing FAS with decreasing T(a).

  12. Aerobic Metabolism of Streptococcus agalactiae

    PubMed Central

    Mickelson, M. N.

    1967-01-01

    Streptococcus agalactiae cultures possess an aerobic pathway for glucose oxidation that is strongly inhibited by cyanide. The products of glucose oxidation by aerobically grown cells of S. agalactiae 50 are lactic and acetic acids, acetylmethylcarbinol, and carbon dioxide. Glucose degradation products by aerobically grown cells, as percentage of glucose carbon, were 52 to 61% lactic acid, 20 to 23% acetic acid, 5.5 to 6.5% acetylmethylcarbinol, and 14 to 16% carbon dioxide. There was no evidence for a pentose cycle or a tricarboxylic acid cycle. Crude cell-free extracts of S. agalactiae 50 possessed a strong reduced nicotinamide adenine dinucleotide (NADH2) oxidase that is also cyanide-sensitive. Dialysis or ultrafiltration of the crude, cell-free extract resulted in loss of NADH2 oxidase activity. Oxidase activity was restored to the inactive extract by addition of the ultrafiltrate or by addition of menadione or K3Fe(CN)6. Noncytochrome iron-containing pigments were present in cell-free extracts of S. agalactiae. The possible participation of these pigments in the respiration of S. agalactiae is presently being studied. PMID:4291090

  13. Steller sea lions (Eumetopias jubatus) have greater blood volumes, higher diving metabolic rates and a longer aerobic dive limit when nutritionally stressed.

    PubMed

    Gerlinsky, Carling D; Trites, Andrew W; Rosen, David A S

    2014-03-01

    Marine mammal foraging behaviour inherently depends on diving ability. Declining populations of Steller sea lions may be facing nutritional stress that could affect their diving ability through changes in body composition or metabolism. Our objective was to determine whether nutritional stress (restricted food intake resulting in a 10% decrease in body mass) altered the calculated aerobic dive limit (cADL) of four captive sea lions diving in the open ocean, and how this related to changes in observed dive behaviour. We measured diving metabolic rate (DMR), blood O2 stores, body composition and dive behaviour prior to and while under nutritional restriction. We found that nutritionally stressed sea lions increased the duration of their single long dives, and the proportion of time they spent at the surface during a cycle of four dives. Nutritionally stressed sea lions lost both lipid and lean mass, resulting in potentially lower muscle O2 stores. However, total body O2 stores increased due to rises in blood O2 stores associated with having higher blood volumes. Nutritionally stressed sea lions also had higher mass-specific metabolic rates. The greater rise in O2 stores relative to the increase in mass-specific DMR resulted in the sea lions having a longer cADL when nutritionally stressed. We conclude that there was no negative effect of nutritional stress on the diving ability of sea lions. However, nutritional stress did lower foraging efficiency and require more foraging time to meet energy requirements due to increases in diving metabolic rates and surface recovery times.

  14. Toxic and inhibitory effects of trichloroethylene aerobic co-metabolism on phenol-grown aerobic granules.

    PubMed

    Zhang, Yi; Tay, JooHwa

    2015-04-09

    Aerobic granule, a form of microbial aggregate, exhibits good potential in degrading toxic and recalcitrant substances. In this study, the inhibitory and toxic effects of trichloroethylene (TCE), a model compound for aerobic co-metabolism, on phenol-grown aerobic granules were systematically studied, using respiratory activities after exposure to TCE as indicators. High TCE concentration did not exert positive or negative effects on the subsequent endogenous respiration rate or phenol dependent specific oxygen utilization rate (SOUR), indicating the absence of solvent stress and induction effect on phenol-hydroxylase. Phenol-grown aerobic granules exhibited a unique response to TCE transformation product toxicity, that small amount of TCE transformation enhanced the subsequent phenol SOUR. Granules that had transformed between 1.3 and 3.7 mg TCE gSS(-1) showed at most 53% increase in the subsequent phenol SOUR, and only when the transformation exceeded 6.6 mg TCE gSS(-1) did the SOUR dropped below that of the control. This enhancing effect was found to sustain throughout several phenol dosages, and TCE transformation below the toxicity threshold also lessened the granules' sensitivity to higher phenol concentration. The unique toxic effect was possibly caused by the granule's compact structure as a protection barrier against the diffusive transformation product(s) of TCE co-metabolism.

  15. Aerobic exercise acutely prevents the endothelial dysfunction induced by mental stress among subjects with metabolic syndrome: the role of shear rate.

    PubMed

    Sales, Allan R K; Fernandes, Igor A; Rocha, Natália G; Costa, Lucas S; Rocha, Helena N M; Mattos, João D M; Vianna, Lauro C; Silva, Bruno M; Nóbrega, Antonio C L

    2014-04-01

    Mental stress induces transient endothelial dysfunction, which is an important finding for subjects at cardiometabolic risk. Thus, we tested whether aerobic exercise prevents this dysfunction among subjects with metabolic syndrome (MetS) and whether an increase in shear rate during exercise plays a role in this phenomenon. Subjects with MetS participated in two protocols. In protocol 1 (n = 16), endothelial function was assessed using brachial artery flow-mediated dilation (FMD). Subjects then underwent a mental stress test followed by either 40 min of leg cycling or rest across two randomized sessions. FMD was assessed again at 30 and 60 min after exercise or rest, with a second mental stress test in between. Mental stress reduced FMD at 30 and 60 min after the rest session (baseline: 7.7 ± 0.4%, 30 min: 5.4 ± 0.5%, and 60 min: 3.9 ± 0.5%, P < 0.05 vs. baseline), whereas exercise prevented this reduction (baseline: 7.5 ± 0.4%, 30 min: 7.2 ± 0.7%, and 60 min: 8.7 ± 0.8%, P > 0.05 vs. baseline). Protocol 2 (n = 5) was similar to protocol 1 except that the first period of mental stress was followed by either exercise in which the brachial artery shear rate was attenuated via forearm cuff inflation or exercise without a cuff. Noncuffed exercise prevented the reduction in FMD (baseline: 7.5 ± 0.7%, 30 min: 7.0 ± 0.7%, and 60 min: 8.7 ± 0.8%, P > 0.05 vs. baseline), whereas cuffed exercise failed to prevent this reduction (baseline: 7.5 ± 0.6%, 30 min: 5.4 ± 0.8%, and 60 min: 4.1 ± 0.9%, P < 0.05 vs. baseline). In conclusion, exercise prevented mental stress-induced endothelial dysfunction among subjects with MetS, and an increase in shear rate during exercise mediated this effect.

  16. Aerobic sugar metabolism in the spoilage yeast Zygosaccharomyces bailii.

    PubMed

    Merico, Annamaria; Capitanio, Daniele; Vigentini, Ileana; Ranzi, Bianca Maria; Compagno, Concetta

    2003-12-01

    Despite the importance of some Zygosaccharomyces species as agents causing spoilage of food, the carbon and energy metabolism of most of them is yet largely unknown. This is the case with Zygosaccharomyces bailii. In this study the occurrence of the Crabtree effect in the petite-negative yeast Z. bailii ATCC 36947 was investigated. In this yeast the aerobic ethanol production is strictly dependent on the carbon source utilised. In glucose-limited continuous cultures a very low level of ethanol was produced. In fructose-limited continuous cultures ethanol was produced at a higher level and its production increased with the dilution rate. As a consequence, on fructose the onset of respiro-fermentative metabolism caused a reduction in biomass yield. An immediate aerobic alcoholic fermentation in Z. bailii was observed during the transition from sugar limitation to sugar excess, both on glucose and on fructose. The analysis of some key enzymes of the fermentative metabolism showed a high level of acetyl-CoA synthetase in Z. bailii growing on fructose. At high dilution rates, the activities of glucose- and fructose-phosphorylating enzymes, as well as of pyruvate decarboxylase and alcohol dehydrogenase, were higher in cells during growth on fructose than on glucose.

  17. Anaerobic Metabolism: Linkages to Trace Gases and Aerobic Processes

    NASA Astrophysics Data System (ADS)

    Megonigal, J. P.; Hines, M. E.; Visscher, P. T.

    2003-12-01

    Life evolved and flourished in the absence of molecular oxygen (O2). As the O2 content of the atmosphere rose to the present level of 21% beginning about two billion years ago, anaerobic metabolism was gradually supplanted by aerobic metabolism. Anaerobic environments have persisted on Earth despite the transformation to an oxidized state because of the combined influence of water and organic matter. Molecular oxygen diffuses about 104 times more slowly through water than air, and organic matter supports a large biotic O2 demand that consumes the supply faster than it is replaced by diffusion. Such conditions exist in wetlands, rivers, estuaries, coastal marine sediments, aquifers, anoxic water columns, sewage digesters, landfills, the intestinal tracts of animals, and the rumen of herbivores. Anaerobic microsites are also embedded in oxic environments such as upland soils and marine water columns. Appreciable rates of aerobic respiration are restricted to areas that are in direct contact with air or those inhabited by organisms that produce O2.Rising atmospheric O2 reduced the global area of anaerobic habitat, but enhanced the overall rate of anaerobic metabolism (at least on an area basis) by increasing the supply of electron donors and acceptors. Organic carbon production increased dramatically, as did oxidized forms of nitrogen, manganese, iron, sulfur, and many other elements. In contemporary anaerobic ecosystems, nearly all of the reducing power is derived from photosynthesis, and most of it eventually returns to O2, the most electronegative electron acceptor that is abundant. This photosynthetically driven redox gradient has been thoroughly exploited by aerobic and anaerobic microorganisms for metabolism. The same is true of hydrothermal vents (Tunnicliffe, 1992) and some deep subsurface environments ( Chapelle et al., 2002), where thermal energy is the ultimate source of the reducing power.Although anaerobic habitats are currently a small fraction of Earth

  18. Metabolic rate measurement system

    NASA Technical Reports Server (NTRS)

    Koester, K.; Crosier, W.

    1980-01-01

    The Metabolic Rate Measurement System (MRMS) is an uncomplicated and accurate apparatus for measuring oxygen consumption and carbon dioxide production of a test subject. From this one can determine the subject's metabolic rate for a variety of conditions, such as resting or light exercise. MRMS utilizes an LSI/11-03 microcomputer to monitor and control the experimental apparatus.

  19. 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

  20. Scaling metabolic rate fluctuations

    PubMed Central

    Labra, Fabio A.; Marquet, Pablo A.; Bozinovic, Francisco

    2007-01-01

    Complex ecological and economic systems show fluctuations in macroscopic quantities such as exchange rates, size of companies or populations that follow non-Gaussian tent-shaped probability distributions of growth rates with power-law decay, which suggests that fluctuations in complex systems may be governed by universal mechanisms, independent of particular details and idiosyncrasies. We propose here that metabolic rate within individual organisms may be considered as an example of an emergent property of a complex system and test the hypothesis that the probability distribution of fluctuations in the metabolic rate of individuals has a “universal” form regardless of body size or taxonomic affiliation. We examined data from 71 individuals belonging to 25 vertebrate species (birds, mammals, and lizards). We report three main results. First, for all these individuals and species, the distribution of metabolic rate fluctuations follows a tent-shaped distribution with power-law decay. Second, the standard deviation of metabolic rate fluctuations decays as a power-law function of both average metabolic rate and body mass, with exponents −0.352 and −1/4 respectively. Finally, we find that the distributions of metabolic rate fluctuations for different organisms can all be rescaled to a single parent distribution, supporting the existence of general principles underlying the structure and functioning of individual organisms. PMID:17578913

  1. Cellular hallmarks reveal restricted aerobic metabolism at thermal limits

    PubMed Central

    Neves, Aitana; Busso, Coralie; Gönczy, Pierre

    2015-01-01

    All organisms live within a given thermal range, but little is known about the mechanisms setting the limits of this range. We uncovered cellular features exhibiting signature changes at thermal limits in Caenorhabditis elegans embryos. These included changes in embryo size and shape, which were also observed in Caenorhabditis briggsae, indicating evolutionary conservation. We hypothesized that such changes could reflect restricted aerobic capacity at thermal limits. Accordingly, we uncovered that relative respiration in C. elegans embryos decreases at the thermal limits as compared to within the thermal range. Furthermore, by compromising components of the respiratory chain, we demonstrated that the reliance on aerobic metabolism is reduced at thermal limits. Moreover, embryos thus compromised exhibited signature changes in size and shape already within the thermal range. We conclude that restricted aerobic metabolism at the thermal limits contributes to setting the thermal range in a metazoan organism. DOI: http://dx.doi.org/10.7554/eLife.04810.001 PMID:25929283

  2. Acclimation of aerobic-activated sludge degrading benzene derivatives and co-metabolic degradation activities of trichloroethylene by benzene derivative-grown aerobic sludge.

    PubMed

    Wang, Shizong; Yang, Qi; Bai, Zhiyong; Wang, Shidong; Wang, Yeyao; Nowak, Karolina M

    2015-01-01

    The acclimation of aerobic-activated sludge for degradation of benzene derivatives was investigated in batch experiments. Phenol, benzoic acid, toluene, aniline and chlorobenzene were concurrently added to five different bioreactors which contained the aerobic-activated sludge. After the acclimation process ended, the acclimated phenol-, benzoic acid-, toluene-, aniline- and chlorobenzene-grown aerobic-activated sludge were used to explore the co-metabolic degradation activities of trichloroethylene (TCE). Monod equation was employed to simulate the kinetics of co-metabolic degradation of TCE by benzene derivative-grown sludge. At the end of experiments, the mixed microbial communities grown under different conditions were identified. The results showed that the acclimation periods of microorganisms for different benzene derivatives varied. The maximum degradation rates of TCE for phenol-, benzoic acid-, toluene-, aniline- and chlorobenzene-grown aerobic sludge were 0.020, 0.017, 0.016, 0.0089 and 0.0047 mg g SS(-1) h(-1), respectively. The kinetic of TCE degradation in the absence of benzene derivative followed Monod equation well. Also, eight phyla were observed in the acclimated benzene derivative-grown aerobic sludge. Each of benzene derivative-grown aerobic sludge had different microbial community composition. This study can hopefully add new knowledge to the area of TCE co-metabolic by mixed microbial communities, and further the understanding on the function and applicability of aerobic-activated sludge.

  3. 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 (Msum = 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 Msum, 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.

  4. Transcriptional Regulation of Aerobic Metabolism in Pichia pastoris Fermentation

    PubMed Central

    Zhang, Biao; Li, Baizhi; Chen, Dai; Zong, Jie; Sun, Fei; Qu, Huixin; Liang, Chongyang

    2016-01-01

    In this study, we investigated the classical fermentation process in Pichia pastoris based on transcriptomics. We utilized methanol in pichia yeast cell as the focus of our study, based on two key steps: limiting carbon source replacement (from glycerol to methonal) and fermentative production of exogenous proteins. In the former, the core differential genes in co-expression net point to initiation of aerobic metabolism and generation of peroxisome. The transmission electron microscope (TEM) results showed that yeast gradually adapted methanol induction to increased cell volume, and decreased density, via large number of peroxisomes. In the fermentative production of exogenous proteins, the Gene Ontology (GO) mapping results show that PAS_chr2-1_0582 played a vital role in regulating aerobic metabolic drift. In order to confirm the above results, we disrupted PAS_chr2-1_0582 by homologous recombination. Alcohol consumption was equivalent to one fifth of the normal control, and fewer peroxisomes were observed in Δ0582 strain following methanol induction. In this study we determined the important core genes and GO terms regulating aerobic metabolic drift in Pichia, as well as developing new perspectives for the continued development within this field. PMID:27537181

  5. 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.

  6. Impact of early fructose intake on metabolic profile and aerobic capacity of rats

    PubMed Central

    2011-01-01

    Background Metabolic syndrome is a disease that today affects millions of people around the world. Therefore, it is of great interest to implement more effective procedures for preventing and treating this disease. In search of a suitable experimental model to study the role of exercise in prevention and treatment of metabolic syndrome, this study examined the metabolic profile and the aerobic capacity of rats kept early in life on a fructose-rich diet, a substrate that has been associated with metabolic syndrome. Methods We used adult female Wistar rats fed during pregnancy and lactation with two diets: balanced or fructose-rich 60%. During breastfeeding, the pups were distributed in small (4/mother) or adequate (8/mother) litters. At 90 days of age, they were analyzed with respect to: glucose tolerance, peripheral insulin sensitivity, aerobic capacity and serum glucose, insulin, triglycerides, total cholesterol, LDL cholesterol and HDL cholesterol concentrations as well as measures of glycogen synthesis and glucose oxidation by the soleus muscle. Results It was found that the fructose rich diet led the animals to insulin resistance. The fructose fed rats kept in small litters also showed dyslipidemia, with increased serum concentrations of total cholesterol and triglycerides. Conclusion Neither the aerobic capacity nor the glucose oxidation rates by the skeletal muscle were altered by fructose-rich diet, indicating that the animal model evaluated is potentially interesting for the study of the role of exercise in metabolic syndrome. PMID:21223589

  7. Impact of salinity on the aerobic metabolism of phosphate-accumulating organisms.

    PubMed

    Welles, L; Lopez-Vazquez, C M; Hooijmans, C M; van Loosdrecht, M C M; Brdjanovic, D

    2015-04-01

    The use of saline water in urban areas for non-potable purposes to cope with fresh water scarcity, intrusion of saline water, and disposal of industrial saline wastewater into the sewerage lead to elevated salinity levels in wastewaters. Consequently, saline wastewater is generated, which needs to be treated before its discharge into surface water bodies. The objective of this research was to study the effects of salinity on the aerobic metabolism of phosphate-accumulating organisms (PAO), which belong to the microbial populations responsible for enhanced biological phosphorus removal (EBPR) in activated sludge systems. In this study, the short-term impact (hours) of salinity (as NaCl) was assessed on the aerobic metabolism of a PAO culture, enriched in a sequencing batch reactor (SBR). All aerobic PAO metabolic processes were drastically affected by elevated salinity concentrations. The aerobic maintenance energy requirement increased, when the salinity concentration rose up to a threshold concentration of 2 % salinity (on a W/V basis as NaCl), while above this concentration, the maintenance energy requirements seemed to decrease. All initial rates were affected by salinity, with the NH4- and PO4-uptake rates being the most sensitive. A salinity increase from 0 to 0.18 % caused a 25, 46, and 63 % inhibition of the O2, PO4, and NH4-uptake rates. The stoichiometric ratios of the aerobic conversions confirmed that growth was the process with the highest inhibition, followed by poly-P and glycogen formation. The study indicates that shock loads of 0.18 % salt, which corresponds to the use or intrusion of about 5 % seawater may severely affect the EBPR process already in wastewater treatment plants not exposed regularly to high salinity concentrations.

  8. Disturbance of aerobic metabolism accompanies neurobehavioral changes induced by nickel in mice.

    PubMed

    He, Min-Di; Xu, Shang-Cheng; Zhang, Xin; Wang, Yan; Xiong, Jia-Chuan; Zhang, Xiao; Lu, Yong-Hui; Zhang, Lei; Yu, Zheng-Ping; Zhou, Zhou

    2013-09-01

    The oral ingestion of soluble nickel compounds leads to neurological symptoms in humans. Deficiencies in aerobic metabolism induced by neurotoxic stimulus can cause an energy crisis in the brain that results in a variety of neurotoxic effects. In the present study, we focused on the aerobic metabolic states to investigate whether disturbance of aerobic metabolism was involved in nickel-induced neurological effects in mice. Mice were orally administered nickel chloride, and neurobehavioral performance was evaluated using the Morris water maze and open field tests at different time points. Aerobic metabolic states in the cerebral cortex were analyzed at the same time points at which neurobehavioral changes were evident. We found that nickel exposure caused deficits in both spatial memory and exploring activity in mice and that nickel was deposited in their cerebral cortex. Deficient aerobic metabolism manifested as decreased O2 consumption and ATP concentrations, lactate and NADH accumulation, and oxidative stress. Meanwhile, the activity of prototypical iron-sulfur clusters (ISCs) containing enzymes that are known to control aerobic metabolism, including complex I and aconitase, and the expression of ISC assembly scaffold protein (ISCU) were inhibited following nickel deposition. Overall, these data suggest that aerobic metabolic disturbances, which accompanied the neurobehavioral changes, may participate in nickel-induced neurologic effects. The inactivation of ISC containing metabolic enzymes may result in the disturbance of aerobic metabolism. A better understanding of how nickel impacts the energy metabolic processes may provide insight into the prevention of nickel neurotoxicity.

  9. Exercise training reverses impaired skeletal muscle metabolism induced by artificial selection for low aerobic capacity

    PubMed Central

    Lessard, Sarah J.; Rivas, Donato A.; Stephenson, Erin J.; Yaspelkis, Ben B.; Koch, Lauren G.; Britton, Steven L.

    2011-01-01

    We have used a novel model of genetically imparted endurance exercise capacity and metabolic health to study the genetic and environmental contributions to skeletal muscle glucose and lipid metabolism. We hypothesized that metabolic abnormalities associated with low intrinsic running capacity would be ameliorated by exercise training. Selective breeding for 22 generations resulted in rat models with a fivefold difference in intrinsic aerobic capacity. Low (LCR)- and high (HCR)-capacity runners remained sedentary (SED) or underwent 6 wk of exercise training (EXT). Insulin-stimulated glucose transport, insulin signal transduction, and rates of palmitate oxidation were lower in LCR SED vs. HCR SED (P < 0.05). Decreases in glucose and lipid metabolism were associated with decreased β2-adrenergic receptor (β2-AR), and reduced expression of Nur77 target proteins that are critical regulators of muscle glucose and lipid metabolism [uncoupling protein-3 (UCP3), fatty acid transporter (FAT)/CD36; P < 0.01 and P < 0.05, respectively]. EXT reversed the impairments to glucose and lipid metabolism observed in the skeletal muscle of LCR, while increasing the expression of β2-AR, Nur77, GLUT4, UCP3, and FAT/CD36 (P < 0.05) in this tissue. However, no metabolic improvements were observed following exercise training in HCR. Our results demonstrate that metabolic impairments resulting from genetic factors (low intrinsic aerobic capacity) can be overcome by an environmental intervention (exercise training). Furthermore, we identify Nur77 as a potential mechanism for improved skeletal muscle metabolism in response to EXT. PMID:21048074

  10. Metabolic correlates of selection on aerobic capacity in laboratory mice: a test of the model for the evolution of endothermy.

    PubMed

    Gebczyński, Andrzej K; Konarzewski, Marek

    2009-09-01

    According to the aerobic capacity model of the evolution of endothermy, high levels of basal/resting metabolic rate (BMR/RMR) underlying endothermy have evolved as a correlated response to selection for high rates of aerobic metabolism (V(O(2)max)). To test the model we studied metabolic, behavioural and morphological correlates of replicated selection on maximum body mass-corrected metabolism elicited by swimming (V(O(2)swim)) in male laboratory mice. While 10 generations of selection did not change body mass, it resulted in a 12% difference in V(O(2)swim) between mice of selected and control line types and significant, correlated responses in maximum metabolic rates elicited by exposure to cold in a helium-oxygen atmosphere (V(O(2)He)), and during forced running on a motorized treadmill (V(O(2)run)). Selected and control lines also significantly differed with respect to duration of running (a measure of stamina, t(run)), and the distance run to exhaustion (d(e)). However, the selection protocol did not result in elevated BMR and voluntary activity. Higher V(O(2)max) in selected animals was positively correlated with higher masses of gastrocnemius muscles and heart but not of other visceral organs (intestine, stomach, liver and kidneys). These findings provide a mechanistic explanation for the lack of correlation between basal and maximal metabolic rates in selected mice. Overall, our study does not support the assumptions of the aerobic capacity model for the evolution of endothermy.

  11. Hindlimb muscle fibre size and glycogen stores in bank voles with increased aerobic exercise metabolism.

    PubMed

    Jaromin, Ewa; Wyszkowska, Julia; Labecka, Anna Maria; Sadowska, Edyta Teresa; Koteja, Paweł

    2016-02-01

    To test hypotheses concerning physiological factors limiting the rate of aerobic exercise metabolism, we used a unique experimental evolution model: lines of bank voles selected for high swim-induced aerobic metabolism (A) and unselected, control lines (C). We investigated putative adaptations that result in the increased performance of the hindlimb muscle (gastrocnemius joined with plantaris). The body mass-adjusted muscle mass was higher in A-lines (0.093 g) than in C-lines (0.083 g; P=0.01). However, selection did not affect mean muscle fibre cross-sectional area (P=0.34) or glycogen content assessed with a histochemical periodic acid-Schiff reaction (PAS; P=0.82). The results suggest that the increased aerobic performance is achieved by an increase of total muscle mass, without major qualitative changes in the muscle fibre architecture. However, such a conclusion should be treated with caution, because other modifications, such as increased density of capillaries or mitochondria, could occur.

  12. The metabolic impact of extracellular nitrite on aerobic metabolism of Paracoccus denitrificans.

    PubMed

    Hartop, K R; Sullivan, M J; Giannopoulos, G; Gates, A J; Bond, P L; Yuan, Z; Clarke, T A; Rowley, G; Richardson, D J

    2017-02-07

    Nitrite, in equilibrium with free nitrous acid (FNA), can inhibit both aerobic and anaerobic growth of microbial communities through bactericidal activities that have considerable potential for control of microbial growth in a range of water systems. There has been much focus on the effect of nitrite/FNA on anaerobic metabolism and so, to enhance understanding of the metabolic impact of nitrite/FNA on aerobic metabolism, a study was undertaken with a model denitrifying bacterium Paracoccus denitrificans PD1222. Extracellular nitrite inhibits aerobic growth of P. denitrificans in a pH-dependent manner that is likely to be a result of both nitrite and free nitrous acid (pKa = 3.25) and subsequent reactive nitrogen oxides generated from the intracellular passage of FNA into P. denitrificans. Increased expression of a gene encoding a flavohemoglobin protein (Fhp) (Pden_1689) was observed in response to extracellular nitrite. Construction and analysis of a deletion mutant established Fhp to be involved in endowing nitrite/FNA resistance at high extracellular nitrite concentrations. Global transcriptional analysis confirmed nitrite-dependent expression of fhp and indicated that P. denitrificans expressed a number of stress response systems associated with protein, DNA and lipid repair. It is therefore suggested that nitrite causes a pH-dependent stress response that is due to the production of associated reactive nitrogen species, such as nitric oxide from the internalisation of FNA.

  13. Rapid growth rates of aerobic anoxygenic phototrophs in the ocean.

    PubMed

    Koblízek, Michal; Masín, Michal; Ras, Josephine; Poulton, Alex J; Prásil, Ondrej

    2007-10-01

    We analysed bacteriochlorophyll diel changes to assess growth rates of aerobic anoxygenic phototrophs in the euphotic zone across the Atlantic Ocean. The survey performed during Atlantic Meridional Transect cruise 16 has shown that bacteriochlorophyll in the North Atlantic Gyre cycles at rates of 0.91-1.08 day(-1) and in the South Atlantic at rates of 0.72-0.89 day(-1). In contrast, in the more productive equatorial region and North Atlantic it cycled at rates of up to 2.13 day(-1). These results suggest that bacteriochlorophyll-containing bacteria in the euphotic zone of the oligotrophic gyres grow at rates of about one division per day and in the more productive regions up to three divisions per day. This is in striking contrast with the relatively slow growth rates of the total bacterial community. Thus, aerobic anoxygenic phototrophs appear to be a very dynamic part of the marine microbial community and due to their rapid growth, they are likely to be larger sinks for dissolved organic matter than their abundance alone would predict.

  14. 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.

  15. 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

  16. Restriction of Aerobic Metabolism by Acquired or Innate Arylsulfatase B Deficiency: A New Approach to the Warburg Effect

    PubMed Central

    Bhattacharyya, Sumit; Feferman, Leo; Tobacman, Joanne K.

    2016-01-01

    Aerobic respiration is required for optimal efficiency of metabolism in mammalian cells. Under circumstances when oxygen utilization is impaired, cells survive by anerobic metabolism. The malignant cell has cultivated the use of anerobic metabolism in an aerobic environment, the Warburg effect, but the explanation for this preference is not clear. This paper presents evidence that deficiency of the enzyme arylsulfatase B (ARSB; N-acetylgalactosamine 4-sulfatase), either innate or acquired, helps to explain the Warburg phenomenon. ARSB is the enzyme that removes 4-sulfate groups from the non-reducing end of chondroitin 4-sulfate and dermatan sulfate. Previous reports indicated reduced ARSB activity in malignancy and replication of the effects of hypoxia by decline in ARSB. Hypoxia reduced ARSB activity, since molecular oxygen is needed for post-translational modification of ARSB. In this report, studies were performed in human HepG2 cells and in hepatocytes from ARSB-deficient and normal C57BL/6J control mice. Decline of ARSB, in the presence of oxygen, profoundly reduced the oxygen consumption rate and increased the extracellular acidification rate, indicating preference for aerobic glycolysis. Specific study findings indicate that decline in ARSB activity enhanced aerobic glycolysis and impaired normal redox processes, consistent with a critical role of ARSB and sulfate reduction in mammalian metabolism. PMID:27605497

  17. Transcription of genes coding for metabolic key functions in Nitrosomonas europaea during aerobic and anaerobic growth.

    PubMed

    Beyer, Sonja; Gilch, Stefan; Meyer, Ortwin; Schmidt, Ingo

    2009-01-01

    Nitrosomonas europaea can grow under conditions of chemolithoautotrophic aerobic (oxygen as oxidant) as well as anaerobic [nitrogen dioxide (NO(2)) as oxidant] nitrification or chemoorganotrophic anaerobic pyruvate-dependent denitrification. In this study, the adaptation of the transcription (mRNA synthesis/concentration) of N. europaea to aerobic and anaerobic growth conditions was evaluated and the transcription of genes coding for metabolic key functions was analyzed: nitrogen and energy metabolism (amoA, hao, rh1, nirK, norB, nsc, aceE, ldhA, ppc, gltA, odhA, coxA), carbon dioxide fixation (cbbL), gluconeogenesis (ppsA), cell growth (ftsZ), and oxidative stress (sodB). During aerobic ammonia oxidation the specific activities of ammonia oxidation, nitrite reduction, and the growth rates correlated with the transcription level of the corresponding genes amoA/hao, nirK/norB/nsc, and cbbL/ftsZ. In anaerobically ammonia-oxidizing cells of N. europaea, the cellular mRNA concentrations of amoA, hao, rh1,coxA, cbbL, ftsZ, and sodB were reduced compared with aerobically nitrifying cells, but the mRNA levels of nirK, norB, and nsc were significantly increased. During anaerobic pyruvate-dependent denitrification, the mRNA abundance of nirK, norB, nsc, aceE, gltA, and odhA was increased, while the concentrations of amoA,hao, rh1, coxAcbbL, ftsZ, and sodB were significantly reduced. Temperature, pH value, and NH(4)(+), O(2), NO, and NO(2) concentrations had comparatively small effects on the transcription of the studied genes.

  18. Proteome analysis of aerobic and fermentative metabolism in Rhizobium etli CE3.

    PubMed

    Encarnación, Sergio; Guzmán, Yudith; Dunn, Michael F; Hernández, Magdalena; del Carmen Vargas, Maria; Mora, Jaime

    2003-06-01

    Rhizobium etli undergoes a transition from an aerobic to a fermentative metabolism during successive subcultures in minimal medium. This metabolic transition does not occur in cells subcultured in rich medium, or in minimal medium containing either biotin or thiamine. In this report, we characterize the aerobic and fermentative metabolism of R. etli using proteome analysis. According to their synthesis patterns in response to aerobic (rich medium, minimal medium with biotin or minimal medium with thiamine) or fermentative (minimal medium without supplements) growth conditions, proteins were assigned to five different classes: (i) proteins produced only in aerobic conditions (e.g., catalase-peroxidase KatG and the E2 component of pyruvate dehydrogenase); (ii) protein produced under both conditions but strongly induced in aerobic metabolism (e.g., malate dehydrogenase and the succinyl-CoA synthetase beta subunit); (iii) proteins that were induced equally under all conditions tested (e.g., AniA, DnaK, and GroEL); (iv) proteins downregulated during aerobic metabolism, and (v) proteins specific to only one of the conditions analyzed. Northern blotting studies of katG expression confirmed the proteome data for this protein. The negative regulation of carbon metabolism proteins observed in fermentative metabolism is consistent with the drastic physiological changes which occur during this process.

  19. 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.

  20. Metabolism of 2-methylpropene (isobutylene) by the aerobic bacterium Mycobacterium sp. strain ELW1.

    PubMed

    Kottegoda, Samanthi; Waligora, Elizabeth; Hyman, Michael

    2015-03-01

    An aerobic bacterium (Mycobacterium sp. strain ELW1) that utilizes 2-methylpropene (isobutylene) as a sole source of carbon and energy was isolated and characterized. Strain ELW1 grew on 2-methylpropene (growth rate = 0.05 h(-1)) with a yield of 0.38 mg (dry weight) mg 2-methylpropene(-1). Strain ELW1 also grew more slowly on both cis- and trans-2-butene but did not grow on any other C2 to C5 straight-chain, branched, or chlorinated alkenes tested. Resting 2-methylpropene-grown cells consumed ethene, propene, and 1-butene without a lag phase. Epoxyethane accumulated as the only detected product of ethene oxidation. Both alkene consumption and epoxyethane production were fully inhibited in cells exposed to 1-octyne, suggesting that alkene oxidation is initiated by an alkyne-sensitive, epoxide-generating monooxygenase. Kinetic analyses indicated that 1,2-epoxy-2-methylpropane is rapidly consumed during 2-methylpropene degradation, while 2-methyl-2-propen-1-ol is not a significant metabolite of 2-methylpropene catabolism. Degradation of 1,2-epoxy-2-methylpropane by 2-methylpropene-grown cells led to the accumulation and further degradation of 2-methyl-1,2-propanediol and 2-hydroxyisobutyrate, two sequential metabolites previously identified in the aerobic microbial metabolism of methyl tert-butyl ether (MTBE) and tert-butyl alcohol (TBA). Growth of strain ELW1 on 2-methylpropene, 1,2-epoxy-2-methylpropane, 2-methyl-1,2-propanediol, and 2-hydroxyisobutyrate was fully inhibited when cobalt ions were omitted from the growth medium, while growth on 3-hydroxybutyrate and other substrates was unaffected by the absence of added cobalt ions. Our results suggest that, like aerobic MTBE- and TBA-metabolizing bacteria, strain ELW1 utilizes a cobalt/cobalamin-dependent mutase to transform 2-hydroxyisobutyrate. Our results have been interpreted in terms of their impact on our understanding of the microbial metabolism of alkenes and ether oxygenates.

  1. Metabolism of 2-Methylpropene (Isobutylene) by the Aerobic Bacterium Mycobacterium sp. Strain ELW1

    PubMed Central

    Kottegoda, Samanthi; Waligora, Elizabeth

    2015-01-01

    An aerobic bacterium (Mycobacterium sp. strain ELW1) that utilizes 2-methylpropene (isobutylene) as a sole source of carbon and energy was isolated and characterized. Strain ELW1 grew on 2-methylpropene (growth rate = 0.05 h−1) with a yield of 0.38 mg (dry weight) mg 2-methylpropene−1. Strain ELW1 also grew more slowly on both cis- and trans-2-butene but did not grow on any other C2 to C5 straight-chain, branched, or chlorinated alkenes tested. Resting 2-methylpropene-grown cells consumed ethene, propene, and 1-butene without a lag phase. Epoxyethane accumulated as the only detected product of ethene oxidation. Both alkene consumption and epoxyethane production were fully inhibited in cells exposed to 1-octyne, suggesting that alkene oxidation is initiated by an alkyne-sensitive, epoxide-generating monooxygenase. Kinetic analyses indicated that 1,2-epoxy-2-methylpropane is rapidly consumed during 2-methylpropene degradation, while 2-methyl-2-propen-1-ol is not a significant metabolite of 2-methylpropene catabolism. Degradation of 1,2-epoxy-2-methylpropane by 2-methylpropene-grown cells led to the accumulation and further degradation of 2-methyl-1,2-propanediol and 2-hydroxyisobutyrate, two sequential metabolites previously identified in the aerobic microbial metabolism of methyl tert-butyl ether (MTBE) and tert-butyl alcohol (TBA). Growth of strain ELW1 on 2-methylpropene, 1,2-epoxy-2-methylpropane, 2-methyl-1,2-propanediol, and 2-hydroxyisobutyrate was fully inhibited when cobalt ions were omitted from the growth medium, while growth on 3-hydroxybutyrate and other substrates was unaffected by the absence of added cobalt ions. Our results suggest that, like aerobic MTBE- and TBA-metabolizing bacteria, strain ELW1 utilizes a cobalt/cobalamin-dependent mutase to transform 2-hydroxyisobutyrate. Our results have been interpreted in terms of their impact on our understanding of the microbial metabolism of alkenes and ether oxygenates. PMID:25576605

  2. High- and moderate-intensity aerobic exercise and excess post-exercise oxygen consumption in men with metabolic syndrome.

    PubMed

    Larsen, I; Welde, B; Martins, C; Tjønna, A E

    2014-06-01

    Physical activity is central in prevention and treatment of metabolic syndrome. High-intensity aerobic exercise can induce larger energy expenditure per unit of time compared with moderate-intensity exercise. Furthermore, it may induce larger energy expenditure at post-exercise recovery. The aim of this study is to compare the excess post-exercise oxygen consumption (EPOC) in three different aerobic exercise sessions in men with metabolic syndrome. Seven men (age: 56.7 ± 10.8) with metabolic syndrome participated in this crossover study. The sessions consisted of one aerobic interval (1-AIT), four aerobic intervals (4-AIT), and 47-min continuous moderate exercise (CME) on separate days, with at least 48 h between each test day. Resting metabolic rate (RMR) was measured pre-exercise and used as baseline value. EPOC was measured until baseline metabolic rate was re-established. An increase in O2 uptake lasting for 70.4 ± 24.8 min (4-AIT), 35.9 ± 17.3 min (1-AIT), and 45.6 ± 17.3 min (CME) was observed. EPOC were 2.9 ± 1.7 L O2 (4-AIT), 1.3 ±  .1 L O2 (1-AIT), and 1.4 ± 1.1 L O2 (CME). There were significant differences (P < 0.001) between 4-AIT, CME, and 1-AIT. Total EPOC was highest after 4-AIT. These data suggest that exercise intensity has a significant positive effect on EPOC in men with metabolic syndrome.

  3. Is the rate of metabolic ageing and survival determined by Basal metabolic rate in the zebra finch?

    PubMed

    Rønning, Bernt; Moe, Børge; Berntsen, Henrik H; Noreen, Elin; Bech, Claus

    2014-01-01

    The relationship between energy metabolism and ageing is of great interest because aerobic metabolism is the primary source of reactive oxygen species which is believed to be of major importance in the ageing process. We conducted a longitudinal study on captive zebra finches where we tested the effect of age on basal metabolic rate (BMR), as well as the effect of BMR on the rate of metabolic ageing (decline in BMR with age) and survival. Basal metabolic rate declined with age in both sexes after controlling for the effect of body mass, indicating a loss of functionality with age. This loss of functionality could be due to accumulated oxidative damage, believed to increase with increasing metabolic rate, c.f. the free radical theory of ageing. If so, we would expect the rate of metabolic ageing to increase and survival to decrease with increasing BMR. However, we found no effect of BMR on the rate of metabolic ageing. Furthermore, survival was not affected by BMR in the males. In female zebra finches there was a tendency for survival to decrease with increasing BMR, but the effect did not reach significance (P<0.1). Thus, the effect of BMR on the rate of functional deterioration with age, if any, was not strong enough to influence neither the rate of metabolic ageing nor survival in the zebra finches.

  4. 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...

  5. Metabolic rate meter and method

    NASA Technical Reports Server (NTRS)

    Taylor, T. I.; Ruderman, I. W. (Inventor)

    1968-01-01

    A method is described for measuring the dynamic metabolic rate of a human or animal. The ratio of the exhaled carbon dioxide to a known amount of C(13)02 introduced into the exhalation is determined by mass spectrometry. This provides an instantaneous measurement of the carbon dioxide generated.

  6. Effects of Exhaustive Aerobic Exercise on Tryptophan-Kynurenine Metabolism in Trained Athletes.

    PubMed

    Strasser, Barbara; Geiger, Daniela; Schauer, Markus; Gatterer, Hannes; Burtscher, Martin; Fuchs, Dietmar

    2016-01-01

    Exhaustive exercise can cause a transient depression of immune function. Data indicate significant effects of immune activation cascades on the biochemistry of monoamines and amino acids such as tryptophan. Tryptophan can be metabolized through different pathways, a major route being the kynurenine pathway, which is often systemically up-regulated when the immune response is activated. The present study was undertaken to examine the effect of exhaustive aerobic exercise on biomarkers of immune activation and tryptophan metabolism in trained athletes. After a standardized breakfast 2 h prior to exercise, 33 trained athletes (17 women, 16 men) performed an incremental cycle ergometer exercise test at 60 rpm until exhaustion. After a 20 min rest phase, the participants performed a 20 min maximal time-trial on a cycle ergometer (RBM Cyclus 2, Germany). During the test, cyclists were strongly encouraged to choose a maximal pedalling rate that could be maintained for the respective test duration. Serum concentrations of amino acids tryptophan, kynurenine, phenylalanine, and tyrosine were determined by HPLC and immune system biomarker neopterin by ELISA at rest and immediately post exercise. Intense exercise was associated with a strong increase in neopterin concentrations (p<0.001), indicating increased immune activation following intense exercise. Exhaustive exercise significantly reduced tryptophan concentrations by 12% (p<0.001) and increased kynurenine levels by 6% (p = 0.022). Also phenylalanine to tyrosine ratios were lower after exercise as compared with baseline (p<0.001). The kynurenine to tryptophan ratio correlated with neopterin (r = 0.560, p<0.01). Thus, increased tryptophan catabolism by indoleamine 2,3-dioxygenase appears likely. Peak oxygen uptake correlated with baseline tryptophan and kynurenine concentrations (r = 0.562 and r = 0.511, respectively, both p<0.01). Findings demonstrate that exhaustive aerobic exercise is associated with increased immune

  7. Resistance to aerobic exercise training causes metabolic dysfunction and reveals novel exercise-regulated signaling networks.

    PubMed

    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

    2013-08-01

    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.

  8. Aerobic Fitness, Heart Rate Recovery and Heart Rate Recovery Time in Indian School Children.

    PubMed

    Fernando, Rajesh Jeniton; Ravichandran, K; Vaz, Mario

    2015-01-01

    Data on aerobic fitness and heart rate recovery in children are limited. This study was done to evaluate the relation between them in Indian school going children. Three hundred children of 7 to 10.5 years were recruited and their aerobic fitness was predicted using modified Harvard's step test (VO₂max) and 20 meter shuttle test (VO₂peak). The heart rate was monitored for 12 minutes post modified Harvard's step test. The difference between the maximum and the 1st minute HR was noted as HRR1 and the time taken to reach the resting heart rate was also recorded. VO₂max was inversely correlated with HRR1 (r = -0.64, p<0.001). However, the partial correlation of the two was not significant (r(partial) = -0.037, p = 0.55), indicating children with higher basal HR had higher HRR1 and that accounted for the observed association with aerobic fitness. Cox regression analysis showed that the recovery rate per unit time was 3% greater with increasing VO₂max (HR = 1.03, 95% CI:1.01 to 1.05, p = 0.013). The heart rate parameters did not show any associat with VO₂peak This study demonstrates that there is no relation between VO₂max and HRR1 after 3 minutes of modified Harvard's step test in Indian children of 7 to 10.5 years. However, aerobic fitness is a positive predictor of heart rate recovery time in this group.

  9. Stimulation of human neutrophil leukocyte aerobic glucose metabolism by purified chemotactic factors.

    PubMed Central

    Goetzl, E J; Austen, K F

    1974-01-01

    The interaction of human neutrophils adherent to plastic petri dishes with the purified chemotactic factors C5a and kallikrein increased their rate of aerobic glycolysis 25-120% and the activity of their hexose monophosphate shunt (HMPS) 100-600%, reaching a plateau after 2 hr at 37 degrees C. The stimulation of either pathway required a chemotactically active stimulus since neither C5 nor prekallikrein or inactivated kallikrein could enhance metabolic activity. Marked suppression of the neutrophil chemotactic response by preincubation with a chemotactic factor to achieve deactivation, 5 x 10(-7) M diisopropyl fluorophosphate, or the neutrophil immobilizing factor (NIF) did not prevent the stimulation of HMPS activity or glycolysis by chemotactic factors. The metabolic inhibitors iodoacetate and 6-aminonicotinamide at concentrations which blocked enhancement of glycolysis or HMPS activity, respectively, partially suppressed the chemotactic response of neutrophils to the chemotactic factors. The capacity of a chemotactic factor to stimulate glucose metabolism of human neutrophils is associated with a maximal chemotactic response, but this stimulation is not alone sufficient for chemotaxis. Images PMID:11344574

  10. Metabolic rates associated with membrane fatty acids in mice selected for increased maximal metabolic rate

    PubMed Central

    Wone, Bernard W. M.; Donovan, Edward R.; Cushman, John C.; Hayes, Jack P.

    2014-01-01

    Aerobic metabolism of vertebrates is linked to membrane fatty acid (FA) composition. Although the membrane pacemaker hypothesis posits that desaturation of FAs accounts for variation in resting or basal metabolic rate (BMR), little is known about the FA profiles that underpin variation in maximal metabolic rate (MMR). We examined membrane FA composition of liver and skeletal muscle in mice after seven generations of selection for increased MMR. In both liver and skeletal muscle, unsaturation index did not differ between control and high-MMR mice. We also examined membrane FA composition at the individual-level of variation. In liver, 18:0, 20:3 n-6, 20:4 n-6, and 22:6 n-3 FAs were significant predictors of MMR. In gastrocnemius muscle, 18:2 n-6, 20:4 n-6, and 22:6 n-3 FAs were significant predictors of MMR. In addition, muscle 16:1 n-7, 18:1 n-9, and 22:5 n-3 FAs were significant predictors of BMR, whereas no liver FAs were significant predictors of BMR. Our findings indicate that (i) individual variation in MMR and BMR appear to be linked to membrane FA composition in the skeletal muscle and liver, and (ii) FAs that differ between selected and control lines are involved in pathways that can affect MMR or BMR. PMID:23422919

  11. Aerobic fitness ecological validity in elite soccer players: a metabolic power approach.

    PubMed

    Manzi, Vincenzo; Impellizzeri, Franco; Castagna, Carlo

    2014-04-01

    The aim of this study was to examine the association between match metabolic power (MP) categories and aerobic fitness in elite-level male soccer players. Seventeen male professional soccer players were tested for VO2max, maximal aerobic speed (MAS), VO2 at ventilatory threshold (VO2VT and %VO2VT), and speed at a selected blood lactate concentration (4 mmol·L(-1), V(L4)). Aerobic fitness tests were performed at the end of preseason and after 12 and 24 weeks during the championship. Aerobic fitness and MP variables were considered as mean of all seasonal testing and of 16 Championship home matches for all the calculations, respectively. Results showed that VO2max (from 0.55 to 0.68), MAS (from 0.52 to 0.72), VO2VT (from 0.72 to 0.83), %VO2maxVT (from 0.62 to 0.65), and V(L4) (from 0.56 to 0.73) were significantly (p < 0.05 to 0.001) large to very large associated with MP variables. These results provide evidence to the ecological validity of aerobic fitness in male professional soccer. Strength and conditioning professionals should consider aerobic fitness in their training program when dealing with professional male soccer players. The MP method resulted an interesting approach for tracking external load in male professional soccer players.

  12. Obesity-Related Hormones and Metabolic Risk Factors: A Randomized Trial of Diet plus Either Strength or Aerobic Training versus Diet Alone in Overweight Participants

    PubMed Central

    Geliebter, Allan; Ochner, Christopher N; Dambkowski, Carl L; Hashim, Sami A

    2014-01-01

    There is debate about the additive effects of exercise in conjunction with diet to treat obesity, and not much is known about the differential effects of strength versus aerobic training. This randomized controlled trial examined the effects of diet plus strength training, diet plus aerobic training, or diet only on metabolic risk factors associated with obesity. Eighty-one overweight and obese participants completed the 8-week intervention. All participants received an energy-restrictive formula diet with an energy content based on 70% of measured resting metabolic rate (RMR). Participants assigned to an exercise group trained 3 days/week under supervision. Anthropometrics and fasting hormones were assessed pre- and post-intervention. Mean weight loss (8.5 ± 4.3kg SD) did not differ between groups nor did reductions in BMI or body fat, although the diet plus strength training group showed marginally greater lean mass retention. There were significant improvements in the values and number of metabolic syndrome risk factors, and decreases in insulin concentrations and insulin resistance, which did not vary between groups. For men, testosterone increased significantly more in the diet plus aerobic training as compared to the other groups. As compared to diet alone, the addition of strength or aerobic training did not improve changes in BMI, body fat or metabolic risk factors although the diet plus strength training group showed a trend toward preservation of lean mass, and the diet plus aerobic group in men resulted in increased testosterone concentrations. PMID:25599089

  13. Speeding up Growth: Selection for Mass-Independent Maximal Metabolic Rate Alters Growth Rates.

    PubMed

    Downs, Cynthia J; Brown, Jessi L; Wone, Bernard W M; Donovan, Edward R; Hayes, Jack P

    2016-03-01

    Investigations into relationships between life-history traits, such as growth rate and energy metabolism, typically focus on basal metabolic rate (BMR). In contrast, investigators rarely examine maximal metabolic rate (MMR) as a relevant metric of energy metabolism, even though it indicates the maximal capacity to metabolize energy aerobically, and hence it might also be important in trade-offs. We studied the relationship between energy metabolism and growth in mice (Mus musculus domesticus Linnaeus) selected for high mass-independent metabolic rates. Selection for high mass-independent MMR increased maximal growth rate, increased body mass at 20 weeks of age, and generally altered growth patterns in both male and female mice. In contrast, there was little evidence that the correlated response in mass-adjusted BMR altered growth patterns. The relationship between mass-adjusted MMR and growth rate indicates that MMR is an important mediator of life histories. Studies investigating associations between energy metabolism and life histories should consider MMR because it is potentially as important in understanding life history as BMR.

  14. Sweat Rates During Continuous and Interval Aerobic Exercise: Implications for NASA Multipurpose Crew Vehicle (MPCV) Missions

    NASA Technical Reports Server (NTRS)

    Ryder, Jeffrey W.; Scott, Jessica; Ploutz-Snyder, Robert; Ploutz-Snyder, Lori L.

    2016-01-01

    Aerobic deconditioning is one of the effects spaceflight. Impaired crewmember performance due to loss of aerobic conditioning is one of the risks identified for mitigation by the NASA Human Research Program. Missions longer than 8 days will involve exercise countermeasures including those aimed at preventing the loss of aerobic capacity. The NASA Multipurpose Crew Vehicle (MPCV) will be NASA's centerpiece architecture for human space exploration beyond low Earth orbit. Aerobic exercise within the small habitable volume of the MPCV is expected to challenge the ability of the environmental control systems, especially in terms of moisture control. Exercising humans contribute moisture to the environment by increased respiratory rate (exhaling air at 100% humidity) and sweat. Current acceptable values are based on theoretical models that rely on an "average" crew member working continuously at 75% of their aerobic capacity (Human Systems Integration Requirements Document). Evidence suggests that high intensity interval exercise for much shorter durations are equally effective or better in building and maintaining aerobic capacity. This investigation will examine sweat and respiratory rates for operationally relevant continuous and interval aerobic exercise protocols using a variety of different individuals. The results will directly inform what types of aerobic exercise countermeasures will be feasible to prescribe for crewmembers aboard the MPCV.

  15. Differential effects of food availability on minimum and maximum rates of metabolism

    PubMed Central

    Salin, Karine; Rudolf, Agata M.; Anderson, Graeme J.; Metcalfe, Neil B.

    2016-01-01

    Metabolic rates reflect the energetic cost of living but exhibit remarkable variation among conspecifics, partly as a result of the constraints imposed by environmental conditions. Metabolic rates are sensitive to changes in temperature and oxygen availability, but effects of food availability, particularly on maximum metabolic rates, are not well understood. Here, we show in brown trout (Salmo trutta) that maximum metabolic rates are immutable but minimum metabolic rates increase as a positive function of food availability. As a result, aerobic scope (i.e. the capacity to elevate metabolism above baseline requirements) declines as food availability increases. These differential changes in metabolic rates likely have important consequences for how organisms partition available metabolic power to different functions under the constraints imposed by food availability. PMID:28120798

  16. Microbial metabolism of pyridine, quinoline, acridine, and their derivatives under aerobic and anaerobic conditions.

    PubMed Central

    Kaiser, J P; Feng, Y; Bollag, J M

    1996-01-01

    Our review of the metabolic pathways of pyridines and aza-arenes showed that biodegradation of heterocyclic aromatic compounds occurs under both aerobic and anaerobic conditions. Depending upon the environmental conditions, different types of bacteria, fungi, and enzymes are involved in the degradation process of these compounds. Our review indicated that different organisms are using different pathways to biotransform a substrate. Our review also showed that the transformation rate of the pyridine derivatives is dependent on the substituents. For example, pyridine carboxylic acids have the highest transformation rate followed by mono-hydroxypyridines, methylpyridines, aminopyridines, and halogenated pyridines. Through the isolation of metabolites, it was possible to demonstrate the mineralization pathway of various heterocyclic aromatic compounds. By using 14C-labeled substrates, it was possible to show that ring fission of a specific heterocyclic compound occurs at a specific position of the ring. Furthermore, many researchers have been able to isolate and characterize the microorganisms or even the enzymes involved in the transformation of these compounds or their derivatives. In studies involving 18O labeling as well as the use of cofactors and coenzymes, it was possible to prove that specific enzymes (e.g., mono- or dioxygenases) are involved in a particular degradation step. By using H2 18O, it could be shown that in certain transformation reactions, the oxygen was derived from water and that therefore these reactions might also occur under anaerobic conditions. PMID:8840783

  17. A combined continuous and interval aerobic training improves metabolic syndrome risk factors in men

    PubMed Central

    Sari-Sarraf, Vahid; Aliasgarzadeh, Akbar; Naderali, Mohammad-Mahdi; Esmaeili, Hamid; Naderali, Ebrahim K

    2015-01-01

    Individuals with metabolic syndrome have significantly higher risk of cardiovascular disease and type 2 diabetes leading to premature death mortality. Metabolic syndrome has a complex etiology; thus, it may require a combined and multi-targeted aerobic exercise regimen to improve risk factors associated with it. Therefore, the aim of this study was to evaluate the effect of combined continuous and interval aerobic training on patients with metabolic syndrome. Thirty adult male with metabolic syndrome (54±8 years) were randomly divided into two groups: test training group (TTG; n=15) and control group (CG; n=15). Subjects in TTG performed combined continuous and interval aerobic training using a motorized treadmill three times per week for 16 weeks. Subjects in CG were advised to continue with their normal activities of life. Twenty-two men completed the study (eleven men in each group). At the end of the study, in TTG, there were significant (for all, P<0.05) reductions in total body weight (−3.2%), waist circumference (−3.43 cm), blood pressure (up to −12.7 mmHg), and plasma insulin, glucose, and triacylglyceride levels. Moreover, there were significant (for all, P<0.05) increases VO2max (−15.3%) and isometric strength of thigh muscle (28.1%) and high-density lipoprotein in TTG. None of the above indices were changed in CG at the end of 16-week study period. Our study suggests that adoption of a 16-week combined continuous and interval aerobic training regimen in men with metabolic syndrome could significantly reduce cardiovascular risk factors in these patients. PMID:26056487

  18. Metabolic Effects of Aerobic Training and Resistance Training in Type 2 Diabetic Subjects

    PubMed Central

    Bacchi, Elisabetta; Negri, Carlo; Zanolin, Maria Elisabetta; Milanese, Chiara; Faccioli, Niccolò; Trombetta, Maddalena; Zoppini, Giacomo; Cevese, Antonio; Bonadonna, Riccardo C.; Schena, Federico; Bonora, Enzo; Lanza, Massimo; Moghetti, Paolo

    2012-01-01

    OBJECTIVE To assess differences between the effects of aerobic and resistance training on HbA1c (primary outcome) and several metabolic risk factors in subjects with type 2 diabetes, and to identify predictors of exercise-induced metabolic improvement. RESEARCH DESIGN AND METHODS Type 2 diabetic patients (n = 40) were randomly assigned to aerobic training or resistance training. Before and after 4 months of intervention, metabolic phenotypes (including HbA1c, glucose clamp–measured insulin sensitivity, and oral glucose tolerance test–assessed β-cell function), body composition by dual-energy X-ray absorptiometry, visceral (VAT) and subcutaneous (SAT) adipose tissue by magnetic resonance imaging, cardiorespiratory fitness, and muscular strength were measured. RESULTS After training, increase in peak oxygen consumption (VO2peak) was greater in the aerobic group (time-by-group interaction P = 0.045), whereas increase in strength was greater in the resistance group (time-by-group interaction P < 0.0001). HbA1c was similarly reduced in both groups (−0.40% [95% CI −0.61 to −0.18] vs. −0.35% [−0.59 to −0.10], respectively). Total and truncal fat, VAT, and SAT were also similarly reduced in both groups, whereas insulin sensitivity and lean limb mass were similarly increased. β-Cell function showed no significant changes. In multivariate analyses, improvement in HbA1c after training was independently predicted by baseline HbA1c and by changes in VO2peak and truncal fat. CONCLUSIONS Resistance training, similarly to aerobic training, improves metabolic features and insulin sensitivity and reduces abdominal fat in type 2 diabetic patients. Changes after training in VO2peak and truncal fat may be primary determinants of exercise-induced metabolic improvement. PMID:22344613

  19. Changes in structure, activity and metabolism of aerobic granules as a microbial response to high phenol loading.

    PubMed

    Jiang, H-L; Tay, J-H; Tay, S T-L

    2004-02-01

    Four column-type sequential aerobic sludge blanket reactors were fed with phenol as the sole carbon and energy source and operated at loading rates of 1.0, 1.5, 2.0 and 2.5 kg phenol m(-3) day(-1). The results indicated that phenol loading exerted a profound influence on the structure, activity and metabolism of the aerobic granules. Compact granules with good settling ability were maintained at loadings up to 2.0 kg phenol m(-3) day(-1), and structurally weakened granules with enhanced production of extracellular polymers and proteins and significantly lower hydrophobicities were observed at the highest loading of 2.5 kg phenol m(-3) day(-1). Specific oxygen uptake rate, catechol 2,3-dioxygenase (C23O) and catechol 1,2-dioxygenase (C12O) activities peaked at a loading of 2.0 kg phenol m(-3) day(-1), and declined thereafter. Granules degraded phenol completely in all four reactors, mainly through the meta cleavage pathway as C23O activities were significantly higher than C12O activities. At the highest loading applied, the anabolism and catabolism of microorganisms were regulated such that phenol degradation proceeded exclusively via the meta pathway, apparently to produce more energy for overstimulation of protein production against phenol toxicity. This work contributes to a better understanding of the ability of aerobic granules to handle high-strength industrial wastewaters containing chemicals that are normally inhibitory to microbial growth.

  20. A new model for the aerobic metabolism of yeast allows the detailed analysis of the metabolic regulation during glucose pulse.

    PubMed

    Kesten, Duygu; Kummer, Ursula; Sahle, Sven; Hübner, Katrin

    2015-11-01

    The onset of aerobic fermentation (the so-called Crabtree effect) in yeast has long been of interest. However, the underlying mechanisms at the metabolic level are not yet fully understood. We developed a detailed kinetic model of the aerobic central metabolism of Saccharomyces cerevisiae comprising glycolysis, TCA cycle and major transport reactions across the mitochondrial membrane to investigate this phenomenon. It is the first one of this extent in the literature. The model is able to reproduce experimental steady state fluxes and time-course behavior after a glucose pulse. Due to the lack of parameter identifiability in the model, we analyze a model ensemble consisting of a set of differently parameterized models for robust findings. The model predicts that the cooperativity of pyruvate decarboxylase with respect to pyruvate and the capacity difference between alcohol dehydrogenase and the pyruvate dehydrogenase bypass play a major role for the onset of the Crabtree effect.

  1. 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.

  2. 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.

  3. 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

  4. Lactate is released and taken up by isolated rabbit vagus nerve during aerobic metabolism.

    PubMed

    Véga, C; Poitry-Yamate, C L; Jirounek, P; Tsacopoulos, M; Coles, J A

    1998-07-01

    To determine if lactate is produced during aerobic metabolism in peripheral nerve, we incubated pieces of rabbit vagus nerve in oxygenated solution containing D-[U-14C]glucose while stimulating electrically. After 30 min, nearly all the radioactivity in metabolites in the nerve was in lactate, glucose 6-phosphate, glutamate, and aspartate. Much lactate was released to the bath: 8.2 pmol (microg dry wt)(-1) from the exogenous glucose and 14.2 pmol (microg dry wt)(-1) from endogenous substrates. Lactate release was not increased when bath PO2 was decreased, indicating that it did not come from anoxic tissue. When the bath contained [U-14C]lactate at a total concentration of 2.13 mM and 1 mM glucose, 14C was incorporated in CO2 and glutamate. The initial rate of formation of CO2 from bath lactate was more rapid than its formation from bath glucose. The results are most readily explained by the hypothesis that has been proposed for brain tissue in which glial cells supply lactate to neurons.

  5. Multiple lines of evidence to demonstrate vinyl chloride aerobic biodegradation in the vadose zone, and factors controlling rates

    NASA Astrophysics Data System (ADS)

    Patterson, B. M.; Aravena, R.; Davis, G. B.; Furness, A. J.; Bastow, T. P.; Bouchard, D.

    2013-10-01

    A field-based investigation was conducted at a contaminated site where the vadose zone was contaminated with a range of chlorinated hydrocarbons. The investigation consisted of groundwater and multilevel soil-gas monitoring of a range of contaminants and gases, along with isotope measurements and microbiology studies. The investigation provided multiple lines of evidence that demonstrated aerobic biodegradation of vinyl chloride (VC) was occurring in the vadose zone (i) above the on-site source zone, and (ii) above the downgradient off-site groundwater plume location. Data from both the on-site and off-site locations were consistent in showing substantially greater (an order of magnitude greater) rates of VC removal from the aerobic vadose zone compared to more recalcitrant contaminants trichloroethene (TCE) and tetrachloroethene (PCE). Soil gas VC isotope analysis showed substantial isotopic enrichment of VC (δ13C - 5.2 to - 10.9‰) compared to groundwater (δ13C - 39.5‰) at the on-site location. Soil gas CO2 isotope analysis at both locations showed that CO2 was highly isotopically depleted (δ13C - 28.8 to - 33.3‰), compared to soil gas CO2 data originating from natural sediment organic matter (δ13C = - 14.7 to - 21.3‰). The soil gas CO2 δ13C values were consistent with near-water table VC groundwater δ13C values (- 36.8 to - 39.5‰), suggesting CO2 originating from aerobic biodegradation of VC. Bacteria that had functional genes (ethene monooxygenase (etnC) and epoxyalkane transferase (etnE) involved in ethene metabolism and VC oxidation were more abundant at the source zone where oxygen co-existed with VC. The distribution of VC and oxygen vadose zone vapour plumes, together with long-term changes in soil gas CO2 concentrations and temperature, provided information to elucidate the factors controlling aerobic biodegradation of VC in the vadose zone. Based on the overlapping VC and oxygen vadose zone vapour plumes, aerobic vapour biodegradation

  6. Multiple lines of evidence to demonstrate vinyl chloride aerobic biodegradation in the vadose zone, and factors controlling rates.

    PubMed

    Patterson, B M; Aravena, R; Davis, G B; Furness, A J; Bastow, T P; Bouchard, D

    2013-10-01

    A field-based investigation was conducted at a contaminated site where the vadose zone was contaminated with a range of chlorinated hydrocarbons. The investigation consisted of groundwater and multilevel soil-gas monitoring of a range of contaminants and gases, along with isotope measurements and microbiology studies. The investigation provided multiple lines of evidence that demonstrated aerobic biodegradation of vinyl chloride (VC) was occurring in the vadose zone (i) above the on-site source zone, and (ii) above the downgradient off-site groundwater plume location. Data from both the on-site and off-site locations were consistent in showing substantially greater (an order of magnitude greater) rates of VC removal from the aerobic vadose zone compared to more recalcitrant contaminants trichloroethene (TCE) and tetrachloroethene (PCE). Soil gas VC isotope analysis showed substantial isotopic enrichment of VC (δ¹³C -5.2 to -10.9‰) compared to groundwater (δ¹³C -39.5‰) at the on-site location. Soil gas CO₂ isotope analysis at both locations showed that CO₂ was highly isotopically depleted (δ¹³C -28.8 to -33.3‰), compared to soil gas CO₂ data originating from natural sediment organic matter (δ¹³C= -14.7 to -21.3‰). The soil gas CO2 δ¹³C values were consistent with near-water table VC groundwater δ¹³C values (-36.8 to -39.5‰), suggesting CO₂ originating from aerobic biodegradation of VC. Bacteria that had functional genes (ethene monooxygenase (etnC) and epoxyalkane transferase (etnE)) involved in ethene metabolism and VC oxidation were more abundant at the source zone where oxygen co-existed with VC. The distribution of VC and oxygen vadose zone vapour plumes, together with long-term changes in soil gas CO₂ concentrations and temperature, provided information to elucidate the factors controlling aerobic biodegradation of VC in the vadose zone. Based on the overlapping VC and oxygen vadose zone vapour plumes, aerobic vapour

  7. 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

  8. Chidamide Inhibits Aerobic Metabolism to Induce Pancreatic Cancer Cell Growth Arrest by Promoting Mcl-1 Degradation

    PubMed Central

    Wang, Yanbing; Kuai, Qiyuan; Li, Changlan; Wang, Yu; Jiang, Xingwei; Wang, Xuanlin; Li, Weijing; He, Min; Ren, Suping; Yu, Qun

    2016-01-01

    Pancreatic cancer is a fatal malignancy worldwide and urgently requires valid therapies. Previous research showed that the HDAC inhibitor chidamide is a promising anti-cancer agent in pancreatic cancer cell lines. In this study, we elucidate a probable underlying anti-cancer mechanism of chidamide involving the degradation of Mcl-1. Mcl-1 is frequently upregulated in human cancers, which has been demonstrated to participate in oxidative phosphorylation, in addition to its anti-apoptotic actions as a Bcl-2 family member. The pancreatic cancer cell lines BxPC-3 and PANC-1 were treated with chidamide, resulting in Mcl-1 degradation accompanied by induction of Mcl-1 ubiquitination. Treatment with MG132, a proteasome inhibitor reduced Mcl-1 degradation stimulated by chidamide. Chidamide decreased O2 consumption and ATP production to inhibit aerobic metabolism in both pancreatic cancer cell lines and primary cells, similar to knockdown of Mcl-1, while overexpression of Mcl-1 in pancreatic cancer cells could restore the aerobic metabolism inhibited by chidamide. Furthermore, chidamide treatment or Mcl-1 knockdown significantly induced cell growth arrest in pancreatic cancer cell lines and primary cells, and Mcl-1 overexpression could reduce this cell growth inhibition. In conclusion, our results suggest that chidamide promotes Mcl-1 degradation through the ubiquitin-proteasome pathway, suppressing the maintenance of mitochondrial aerobic respiration by Mcl-1, and resulting in inhibition of pancreatic cancer cell proliferation. Our work supports the claim that chidamide has therapeutic potential for pancreatic cancer treatment. PMID:27875574

  9. High diving metabolism results in a short aerobic dive limit for Steller sea lions (Eumetopias jubatus).

    PubMed

    Gerlinsky, Carling D; Rosen, David A S; Trites, Andrew W

    2013-07-01

    The diving capacity of marine mammals is typically defined by the aerobic dive limit (ADL) which, in lieu of direct measurements, can be calculated (cADL) from total body oxygen stores (TBO) and diving metabolic rate (DMR). To estimate cADL, we measured blood oxygen stores, and combined this with diving oxygen consumption rates (VO2) recorded from 4 trained Steller sea lions diving in the open ocean to depths of 10 or 40 m. We also examined the effect of diving exercise on O2 stores by comparing blood O2 stores of our diving animals to non-diving individuals at an aquarium. Mass-specific blood volume of the non-diving individuals was higher in the winter than in summer, but there was no overall difference in blood O2 stores between the diving and non-diving groups. Estimated TBO (35.9 ml O2 kg(-1)) was slightly lower than previously reported for Steller sea lions and other Otariids. Calculated ADL was 3.0 min (based on an average DMR of 2.24 L O2 min(-1)) and was significantly shorter than the average 4.4 min dives our study animals performed when making single long dives-but was similar to the times recorded during diving bouts (a series of 4 dives followed by a recovery period on the surface), as well as the dive times of wild animals. Our study is the first to estimate cADL based on direct measures of VO2 and blood oxygen stores for an Otariid and indicates they have a much shorter ADL than previously thought.

  10. 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

  11. Resting Metabolic Rate is Not Reduced in Obese Adults With Down Syndrome

    ERIC Educational Resources Information Center

    Fernhall, Bo; Figueroa, Arturo; Collier, Scott; Goulopoulou, Styliani; Giannopoulou, Ifigenia; Baynard, Tracy

    2005-01-01

    Resting metabolic rate (RMR) of 22 individuals with Down syndrome was compared to that of 20 nondisabled control individuals of similar age (25.7 and 27.4 years, respectively). Using a ventilated hood system, we measured RMR in the early morning after an overnight fast. Peak aerobic capacity Volume of Oxygen (VO2 peak) and body composition were…

  12. Exosomes from human mesenchymal stem cells conduct aerobic metabolism in term and preterm newborn infants.

    PubMed

    Panfoli, Isabella; Ravera, Silvia; Podestà, Marina; Cossu, Claudia; Santucci, Laura; Bartolucci, Martina; Bruschi, Maurizio; Calzia, Daniela; Sabatini, Federica; Bruschettini, Matteo; Ramenghi, Luca Antonio; Romantsik, Olga; Marimpietri, Danilo; Pistoia, Vito; Ghiggeri, Gianmarco; Frassoni, Francesco; Candiano, Giovanni

    2016-04-01

    Exosomes are secreted nanovesicles that are able to transfer RNA and proteins to target cells. The emerging role of mesenchymal stem cell (MSC) exosomes as promoters of aerobic ATP synthesis restoration in damaged cells, prompted us to assess whether they contain an extramitochondrial aerobic respiration capacity. Exosomes were isolated from culture medium of human MSCs from umbilical cord of ≥37-wk-old newborns or between 28- to 30-wk-old newborns (i.e.,term or preterm infants). Characterization of samples was conducted by cytofluorometry. Oxidative phosphorylation capacity was assessed by Western blot analysis, oximetry, and luminometric and fluorometric analyses. MSC exosomes express functional respiratory complexes I, IV, and V, consuming oxygen. ATP synthesis was only detectable in exosomes from term newborns, suggestive of a specific mechanism that is not completed at an early gestational age. Activities are outward facing and comparable to those detected in mitochondria isolated from term MSCs. MSC exosomes display an unsuspected aerobic respiratory ability independent of whole mitochondria. This may be relevant for their ability to rescue cell bioenergetics. The differential oxidative metabolism of pretermvs.term exosomes sheds new light on the preterm newborn's clinical vulnerability. A reduced ability to repair damaged tissue and an increased capability to cope with anoxic environment for preterm infants can be envisaged.-Panfoli, I., Ravera, S., Podestà, M., Cossu, C., Santucci, L., Bartolucci, M., Bruschi, M., Calzia, D., Sabatini, F., Bruschettini, M., Ramenghi, L. A., Romantsik, O., Marimpietri, D., Pistoia, V., Ghiggeri, G., Frassoni, F., Candiano, G. Exosomes from human mesenchymal stem cells conduct aerobic metabolism in term and preterm newborn infants.

  13. Metabolic response of different high-intensity aerobic interval exercise protocols.

    PubMed

    Gosselin, Luc E; Kozlowski, Karl F; DeVinney-Boymel, Lee; Hambridge, Caitlin

    2012-10-01

    Although high-intensity sprint interval training (SIT) employing the Wingate protocol results in significant physiological adaptations, it is conducted at supramaximal intensity and is potentially unsafe for sedentary middle-aged adults. We therefore evaluated the metabolic and cardiovascular response in healthy young individuals performing 4 high-intensity (~90% VO2max) aerobic interval training (HIT) protocols with similar total work output but different work-to-rest ratio. Eight young physically active subjects participated in 5 different bouts of exercise over a 3-week period. Protocol 1 consisted of 20-minute continuous exercise at approximately 70% of VO2max, whereas protocols 2-5 were interval based with a work-active rest duration (in seconds) of 30/30, 60/30, 90/30, and 60/60, respectively. Each interval protocol resulted in approximately 10 minutes of exercise at a workload corresponding to approximately 90% VO2max, but differed in the total rest duration. The 90/30 HIT protocol resulted in the highest VO2, HR, rating of perceived exertion, and blood lactate, whereas the 30/30 protocol resulted in the lowest of these parameters. The total caloric energy expenditure was lowest in the 90/30 and 60/30 protocols (~150 kcal), whereas the other 3 protocols did not differ (~195 kcal) from one another. The immediate postexercise blood pressure response was similar across all the protocols. These finding indicate that HIT performed at approximately 90% of VO2max is no more physiologically taxing than is steady-state exercise conducted at 70% VO2max, but the response during HIT is influenced by the work-to-rest ratio. This interval protocol may be used as an alternative approach to steady-state exercise training but with less time commitment.

  14. Redox-sensing regulator Rex regulates aerobic metabolism, morphological differentiation, and avermectin production in Streptomyces avermitilis

    PubMed Central

    Liu, Xingchao; Cheng, Yaqing; Lyu, Mengya; Wen, Ying; Song, Yuan; Chen, Zhi; Li, Jilun

    2017-01-01

    The regulatory role of redox-sensing regulator Rex was investigated in Streptomyces avermitilis. Eleven genes/operons were demonstrated to be directly regulated by Rex; these genes/operons are involved in aerobic metabolism, morphological differentiation, and secondary metabolism. Rex represses transcription of target genes/operons by binding to Rex operator (ROP) sequences in the promoter regions. NADH reduces DNA-binding activity of Rex to target promoters, while NAD+ competitively binds to Rex and modulates its DNA-binding activity. Rex plays an essential regulatory role in aerobic metabolism by controlling expression of the respiratory genes atpIBEFHAGDC, cydA1B1CD, nuoA1-N1, rex-hemAC1DB, hppA, and ndh2. Rex also regulates morphological differentiation by repressing expression of wblE, which encodes a putative WhiB-family transcriptional regulator. A rex-deletion mutant (Drex) showed higher avermectin production than the wild-type strain ATCC31267, and was more tolerant of oxygen limitation conditions in regard to avermectin production. PMID:28303934

  15. A strong response to selection on mass-independent maximal metabolic rate without a correlated response in basal metabolic rate.

    PubMed

    Wone, B W M; Madsen, P; Donovan, E R; Labocha, M K; Sears, M W; Downs, C J; Sorensen, D A; Hayes, J P

    2015-04-01

    Metabolic rates are correlated with many aspects of ecology, but how selection on different aspects of metabolic rates affects their mutual evolution is poorly understood. Using laboratory mice, we artificially selected for high maximal mass-independent metabolic rate (MMR) without direct selection on mass-independent basal metabolic rate (BMR). Then we tested for responses to selection in MMR and correlated responses to selection in BMR. In other lines, we antagonistically selected for mice with a combination of high mass-independent MMR and low mass-independent BMR. All selection protocols and data analyses included body mass as a covariate, so effects of selection on the metabolic rates are mass adjusted (that is, independent of effects of body mass). The selection lasted eight generations. Compared with controls, MMR was significantly higher (11.2%) in lines selected for increased MMR, and BMR was slightly, but not significantly, higher (2.5%). Compared with controls, MMR was significantly higher (5.3%) in antagonistically selected lines, and BMR was slightly, but not significantly, lower (4.2%). Analysis of breeding values revealed no positive genetic trend for elevated BMR in high-MMR lines. A weak positive genetic correlation was detected between MMR and BMR. That weak positive genetic correlation supports the aerobic capacity model for the evolution of endothermy in the sense that it fails to falsify a key model assumption. Overall, the results suggest that at least in these mice there is significant capacity for independent evolution of metabolic traits. Whether that is true in the ancestral animals that evolved endothermy remains an important but unanswered question.

  16. A strong response to selection on mass-independent maximal metabolic rate without a correlated response in basal metabolic rate

    PubMed Central

    Wone, B W M; Madsen, P; Donovan, E R; Labocha, M K; Sears, M W; Downs, C J; Sorensen, D A; Hayes, J P

    2015-01-01

    Metabolic rates are correlated with many aspects of ecology, but how selection on different aspects of metabolic rates affects their mutual evolution is poorly understood. Using laboratory mice, we artificially selected for high maximal mass-independent metabolic rate (MMR) without direct selection on mass-independent basal metabolic rate (BMR). Then we tested for responses to selection in MMR and correlated responses to selection in BMR. In other lines, we antagonistically selected for mice with a combination of high mass-independent MMR and low mass-independent BMR. All selection protocols and data analyses included body mass as a covariate, so effects of selection on the metabolic rates are mass adjusted (that is, independent of effects of body mass). The selection lasted eight generations. Compared with controls, MMR was significantly higher (11.2%) in lines selected for increased MMR, and BMR was slightly, but not significantly, higher (2.5%). Compared with controls, MMR was significantly higher (5.3%) in antagonistically selected lines, and BMR was slightly, but not significantly, lower (4.2%). Analysis of breeding values revealed no positive genetic trend for elevated BMR in high-MMR lines. A weak positive genetic correlation was detected between MMR and BMR. That weak positive genetic correlation supports the aerobic capacity model for the evolution of endothermy in the sense that it fails to falsify a key model assumption. Overall, the results suggest that at least in these mice there is significant capacity for independent evolution of metabolic traits. Whether that is true in the ancestral animals that evolved endothermy remains an important but unanswered question. PMID:25604947

  17. Local metabolic rate during whole body vibration.

    PubMed

    Friesenbichler, Bernd; Nigg, Benno M; Dunn, Jeff F

    2013-05-15

    Whole body vibration (WBV) platforms are currently used for muscle training and rehabilitation. However, the effectiveness of WBV training remains elusive, since scientific studies vary largely in the vibration parameters used. The origin of this issue may be related to a lack in understanding of the training intensity that is imposed on individual muscles by WBV. Therefore, this study evaluates the training intensity in terms of metabolic rate of two lower-extremity muscles during WBV under different vibration parameters. Fourteen healthy male subjects were randomly exposed to 0 (control)-, 10-, 17-, and 28-Hz vibrations while standing upright on a vibration platform. A near-infrared spectrometer was used to determine the gastrocnemius medialis (GM) and vastus lateralis (VL) muscles' metabolic rates during arterial occlusion. The metabolic rates during each vibration condition were significantly higher compared with control for both muscles (P < 0.05). Each increase in vibration frequency translated into a significantly higher metabolic rate than the previous lower frequency (P < 0.05) for both muscles. The current study showed that the local metabolic rate during WBV at 28 Hz was on average 5.4 times (GM) and 3.7 times (VL) of the control metabolic rate. The substantial changes in local metabolic rate indicate that WBV may represent a significant local training stimulus for particular leg muscles.

  18. Global gene expression analysis of glucose overflow metabolism in Escherichia coli and reduction of aerobic acetate formation.

    PubMed

    Veit, Andrea; Polen, Tino; Wendisch, Volker F

    2007-02-01

    During aerobic growth on glucose, Escherichia coli produces acetate in the so-called overflow metabolism. DNA microarray analysis was used to determine the global gene expression patterns of chemostat cultivations of E. coli MG1655 that were characterized by different acetate formation rates during aerobic growth on glucose. A correlation analysis identified that expression of ten genes (sdhCDAB, sucB, sucC, acnB, lpdA, fumC and mdh) encoding the TCA cycle enzymes succinate dehydrogenase, alpha-ketoglutarate dehydrogenase, succinyl-CoA synthetase, aconitase, fumarase and malate dehydrogenase, respectively, and of the acs-yjcH-actP operon for acetate utilization correlated negatively with acetate formation. Relieving transcriptional control of the sdhCDAB-b0725-sucABCD operon by chromosomal promoter exchange mutagenesis yielded a strain with increased specific activities of the TCA cycle enzymes succinate dehydrogenase, alpha-ketoglutarate dehydrogenase and succinyl-CoA synthetase, which are encoded by this operon. The resulting strain produced less acetate and directed more carbon towards carbon dioxide formation than the parent strain MG1655 while maintaining high growth and glucose consumption rates.

  19. Importance of both fatness and aerobic fitness on metabolic syndrome risk in Japanese children.

    PubMed

    Sasayama, Kensaku; Ochi, Eisuke; Adachi, Minoru

    2015-01-01

    Associations between body mass index (BMI), peak oxygen consumption (VO(2peak)), and metabolic syndrome (MetS) risk factors have not been adequately studied in Japanese children. Here the relationships between these parameters and the threshold aerobic fitness level necessary for low MetS risk were determined. The participants (299 children; 140 boys and 159 girls, aged 9.1 ± 0.3 years) were divided into four groups using the medians of predicted VO(2peak) (pVO(2peak)) and BMI. MetS risk scores were calculated using z-scores. Receiver Operating Characteristic analysis was used to determine the threshold aerobic fitness level necessary for low MetS risk. The MetS risk score of the High BMI group was significantly higher than that of the Low BMI group for both sexes (p < 0.0001). However, the High BMI/High Fitness group had a significantly lower MetS risk score than the High BMI/Low Fitness group for both sexes. The (p)VO(2peak )cut-off values for low MetS risk were 47.9 and 44.9 ml/kg/min for boys and girls, respectively. Our results suggest that improvements in both fatness and aerobic fitness are important for decreasing MetS risk. We also confirmed the (p)VO(2peak) of cut-off values necessary for low MetS risk in Japanese children.

  20. Importance of Both Fatness and Aerobic Fitness on Metabolic Syndrome Risk in Japanese Children

    PubMed Central

    Sasayama, Kensaku; Ochi, Eisuke; Adachi, Minoru

    2015-01-01

    Associations between body mass index (BMI), peak oxygen consumption (VO2peak), and metabolic syndrome (MetS) risk factors have not been adequately studied in Japanese children. Here the relationships between these parameters and the threshold aerobic fitness level necessary for low MetS risk were determined. The participants (299 children; 140 boys and 159 girls, aged 9.1 ± 0.3 years) were divided into four groups using the medians of predicted VO2peak (pVO2peak) and BMI. MetS risk scores were calculated using z-scores. Receiver Operating Characteristic analysis was used to determine the threshold aerobic fitness level necessary for low MetS risk. The MetS risk score of the High BMI group was significantly higher than that of the Low BMI group for both sexes (p < 0.0001). However, the High BMI/High Fitness group had a significantly lower MetS risk score than the High BMI/Low Fitness group for both sexes. The pVO2peak cut-off values for low MetS risk were 47.9 and 44.9 ml/kg/min for boys and girls, respectively. Our results suggest that improvements in both fatness and aerobic fitness are important for decreasing MetS risk. We also confirmed the pVO2peak of cut-off values necessary for low MetS risk in Japanese children. PMID:25993528

  1. Biodegradation and kinetics of aerobic granules under high organic loading rates in sequencing batch reactor.

    PubMed

    Chen, Yao; Jiang, Wenju; Liang, David Tee; Tay, Joo Hwa

    2008-05-01

    Biodegradation, kinetics, and microbial diversity of aerobic granules were investigated under a high range of organic loading rate 6.0 to 12.0 kg chemical oxygen demand (COD) m(-3) day(-1) in a sequencing batch reactor. The selection and enriching of different bacterial species under different organic loading rates had an important effect on the characteristics and performance of the mature aerobic granules and caused the difference on granular biodegradation and kinetic behaviors. Good granular characteristics and performance were presented at steady state under various organic loading rates. Larger and denser aerobic granules were developed and stabilized at relatively higher organic loading rates with decreased bioactivity in terms of specific oxygen utilization rate and specific growth rate (muoverall) or solid retention time. The decrease of bioactivity was helpful to maintain granule stability under high organic loading rates and improve reactor operation. The corresponding biokinetic coefficients of endogenous decay rate (kd), observed yield (Yobs), and theoretical yield (Y) were measured and calculated in this study. As the increase of organic loading rate, a decreased net sludge production (Yobs) is associated with an increased solid retention time, while kd and Y changed insignificantly and can be regarded as constants under different organic loading rates.

  2. Comparison of body composition, heart rate variability, aerobic and anaerobic performance between competitive cyclists and triathletes

    PubMed Central

    Arslan, Erşan; Aras, Dicle

    2016-01-01

    [Purpose] The aim of this study was to compare the body composition, heart rate variability, and aerobic and anaerobic performance between competitive cyclists and triathletes. [Subjects] Six cyclists and eight triathletes with experience in competitions voluntarily participated in this study. [Methods] The subjects’ body composition was measured with an anthropometric tape and skinfold caliper. Maximal oxygen consumption and maximum heart rate were determined using the incremental treadmill test. Heart rate variability was measured by 7 min electrocardiographic recording. The Wingate test was conducted to determine anaerobic physical performance. [Results] There were significant differences in minimum power and relative minimum power between the triathletes and cyclists. Anthropometric characteristics and heart rate variability responses were similar among the triathletes and cyclists. However, triathletes had higher maximal oxygen consumption and lower resting heart rates. This study demonstrated that athletes in both sports have similar body composition and aerobic performance characteristics. PMID:27190476

  3. Heart rate recovery after aerobic and anaerobic tests: is there an influence of anaerobic speed reserve?

    PubMed

    Del Rosso, Sebastián; Nakamura, Fabio Y; Boullosa, Daniel A

    2017-05-01

    The present study assessed if differences in the metabolic profile, inferred from the anaerobic speed reserve (ASR), would influence the dynamics of heart rate recovery (HRR) after two modes of exercise. Thirty-nine physical education students (14 females and 25 males) volunteered for this study. Participants carried out three separate testing sessions to assess maximal sprinting speed (MSS, 1st session), repeated sprint ability (RSA, 2nd session) and maximal aerobic speed (MAS) using the Université of Montreal Track Test (UMTT, 3rd session). ASR was defined as the difference between MSS and MAS. Heart rate was continuously registered throughout the tests and during the 5-min post-test recovery. To evaluate the influence of ASR on post-exercise, HRR comparisons between ASR-based groups [high ASR vs. low ASR] and sex groups (males vs. females) were performed. Significant differences (P < 0.05) were found between high ASR and low ASR groups of the same sex for indices of relative HRR after the RSA and UMTT. In addition, after the RSA test, males from the high ASR group had a significantly slower HRR kinetics compared with the males of the low ASR (P < 0.05) and the females of high ASR (P < 0.05); whereas females of the high ASR groups had a faster HRR kinetics compared with the females of low ASR group (P < 0.05). Our results showed that in males, post-exercise HRR could be related to the ASR, whereas in females, the influence of ASR is less clear.

  4. Impact of a 12-week aerobic exercise training program on anthropometric and metabolic parameters of a group of type 2 diabetes Cameroonian women aged ≥50 years

    PubMed Central

    Dahjio, Yves; Noubiap, Jean Jacques N.; Azabji-Kenfack, Marcel; Essouma, Mickael; Loni, Gabriel Ekali; Onana, Arnold Ewane; Dehayem, Mesmin; Mvom, Angeline; Tadjore, Maurice Njock

    2016-01-01

    Background We examined whether aerobic exercise could have an impact on anthropometric and metabolic parameters of type 2 diabetes mellitus (T2DM) Cameroonian women aged ≥50 years. Methods We enrolled 23 T2DM Cameroonian women aged ≥50 years regularly followed at the National Obesity Center of Yaounde, Cameroon, in a 12-week aerobic exercise program monitored by a pedometer. Exercise intensity was progressively set between 55% and 75% of maximum heart rate. We measured weight, body mass index (BMI), fat, lean mass, visceral fat, maximum oxygen uptake, glycaemia and insulin tolerance index at baseline, after six and twelve weeks. A mixed ANOVA model was used to evaluate changes of outcome measures over time. Results Total body weight was significantly reduced after 12 weeks (P<0.05), waist circumference after 6 and 12 weeks (P<0.05). There was an increase of the lean mass from 6 weeks (P<0.001) and a reduction of the mean visceral fat at 12 weeks (P<0.001). At the end of the program, the mean glycaemia was significantly decreased (P<0.05), and the maximum oxygen uptake was enhanced (P<0.05). Conclusions The 12-week aerobic exercise program improved the anthropometric and metabolic parameters as well as the aerobic capacity of T2DM Cameroonian women aged ≥50 years. PMID:27826567

  5. Estimation of Warfighter Resting Metabolic Rate

    DTIC Science & Technology

    2005-04-14

    influencing basal metabolic rate in normal adults. Am J Clin Nutr 33:2372-2374, 1980. Daly, J.M.; Heymsfield, S.B.; Head, C.A.; Harvey, L.P.; Nixon, D.W...Reappraisal of the resting metabolic rate of normal young men. Am J Clin Nutr 53(1):21-26, 1991. Cunningham, J.L. A reanalysis of the factors

  6. Simple estimate of the human metabolic rate

    NASA Astrophysics Data System (ADS)

    Graham, Daniel J.; Schacht, David V.

    2001-06-01

    A method for estimating the human metabolic rate is described. It entails measuring the rate at which carbon dioxide is produced by glucose oxidation during respiration. Such measurements can enhance classroom presentations of the concept of energy and its interconversion. Measurements of this type can also augment classroom discussions of related topics such as entropy production in nonequilibrium systems. The ideas are appropriate at both the high school and college levels and should appeal to student interest in metabolism, physiology, and medical physics.

  7. Antioxidants, metabolic rate and aging in Drosophila

    NASA Technical Reports Server (NTRS)

    Miquel, J.; Fleming, J.; Economos, A. C.

    1982-01-01

    The metabolic rate-of-living theory of aging was investigated by determining the effect of several life-prolonging antioxidants on the metabolic rate and life span of Drosophila. The respiration rate of groups of continuously agitated flies was determined in a Gilson respirometer. Vitamin E, 2,4-dinitrophenol, nordihydroguaiaretic acid, and thiazolidine carboxylic acid were employed as antioxidants. Results show that all of these antioxidants reduced the oxygen consumption rate and increased the mean life span, and a significant negative linear correlation was found between the mean life span and the metabolic rate. It is concluded that these findings indicate that some antioxidants may inhibit respiration rate in addition to their protective effect against free radical-induced cellular damage.

  8. Measurement and relevance of maximum metabolic rate in fishes.

    PubMed

    Norin, T; Clark, T D

    2016-01-01

    Maximum (aerobic) metabolic rate (MMR) is defined here as the maximum rate of oxygen consumption (M˙O2max ) that a fish can achieve at a given temperature under any ecologically relevant circumstance. Different techniques exist for eliciting MMR of fishes, of which swim-flume respirometry (critical swimming speed tests and burst-swimming protocols) and exhaustive chases are the most common. Available data suggest that the most suitable method for eliciting MMR varies with species and ecotype, and depends on the propensity of the fish to sustain swimming for extended durations as well as its capacity to simultaneously exercise and digest food. MMR varies substantially (>10 fold) between species with different lifestyles (i.e. interspecific variation), and to a lesser extent (aerobic scope, interest in measuring this trait has spread across disciplines in attempts to predict effects of climate change on fish populations. Here, various techniques used to elicit and measure MMR in different fish species with contrasting lifestyles are outlined and the relevance of MMR to the ecology, fitness and climate change resilience of fishes is discussed.

  9. Estimation of rates of aerobic hydrocarbon biodegradation by simulation of gas transport in the unsaturated zone

    USGS Publications Warehouse

    Lahvis, M.A.; Baehr, A.L.

    1996-01-01

    The distribution of oxygen and carbon dioxide gases in the unsaturated zone provides a geochemical signature of aerobic hydrocarbon degradation at petroleum product spill sites. The fluxes of these gases are proportional to the rate of aerobic biodegradation and are quantified by calibrating a mathematical transport model to the oxygen and carbon dioxide gas concentration data. Reaction stoichiometry is assumed to convert the gas fluxes to a corresponding rate of hydrocarbon degradation. The method is applied at a gasoline spill site in Galloway Township, New Jersey, to determine the rate of aerobic degradation of hydrocarbons associated with passive and bioventing remediation field experiments. At the site, microbial degradation of hydrocarbons near the water table limits the migration of hydrocarbon solutes in groundwater and prevents hydrocarbon volatilization into the unsaturated zone. In the passive remediation experiment a site-wide degradation rate estimate of 34,400 g yr-1 (11.7 gal. yr-1) of hydrocarbon was obtained by model calibration to carbon dioxide gas concentration data collected in December 1989. In the bioventing experiment, degradation rate estimates of 46.0 and 47.9 g m-2 yr-1 (1.45 x 10-3 and 1.51 x 10-3 gal. ft.-2 yr-1) of hydrocarbon were obtained by model calibration to oxygen and carbon dioxide gas concentration data, respectively. Method application was successful in quantifying the significance of a naturally occurring process that can effectively contribute to plume stabilization.

  10. Estimation of rates of aerobic hydrocarbon biodegradation by simulation of gas transport in the unsaturated zone

    NASA Astrophysics Data System (ADS)

    Lahvis, Matthew A.; Baehr, Arthur L.

    1996-07-01

    The distribution of oxygen and carbon dioxide gases in the unsaturated zone provides a geochemical signature of aerobic hydrocarbon degradation at petroleum product spill sites. The fluxes of these gases are proportional to the rate of aerobic biodegradation and are quantified by calibrating a mathematical transport model to the oxygen and carbon dioxide gas concentration data. Reaction stoichiometry is assumed to convert the gas fluxes to a corresponding rate of hydrocarbon degradation. The method is applied at a gasoline spill site in Galloway Township, New Jersey, to determine the rate of aerobic degradation of hydrocarbons associated with passive and bioventing remediation field experiments. At the site, microbial degradation of hydrocarbons near the water table limits the migration of hydrocarbon solutes in groundwater and prevents hydrocarbon volatilization into the unsaturated zone. In the passive remediation experiment a site-wide degradation rate estimate of 34,400 gyr-1 (11.7 gal. yr-1) of hydrocarbon was obtained by model calibration to carbon dioxide gas concentration data collected in December 1989. In the bioventing experiment, degradation rate estimates of 46.0 and 47.9 gm-2yr-1 (1.45×10-3 and 1.51×10-3 gal.ft.-2yr-1) of hydrocarbon were obtained by model calibration to oxygen and carbon dioxide gas concentration data, respectively. Method application was successful in quantifying the significance of a naturally occurring process that can effectively contribute to plume stabilization.

  11. Black and White race differences in aerobic capacity, muscle fiber type, and their influence on metabolic processes.

    PubMed

    Ceaser, Tyrone; Hunter, Gary

    2015-05-01

    Obesity is a known risk factor for cardiometabolic disease. Increasing aerobic capacity (VO2max) reduces adiposity, maintains weight, and reduces the risk of developing obesity and cardiometabolic disease. Two major determinants of aerobic capacity are the metabolic properties specific to a particular muscle fiber type and the capacity of the cardiorespiratory system to deliver nutrient-rich content to the muscle. Recent research suggests that some race/ethnic groups, particularly non-Hispanic Black subjects, are predisposed to a reduced VO2max by way of muscle fiber type. Combined with insufficient physical activity, these characteristics place non-Hispanic Black subjects at an increased risk for obesity and other adverse health outcomes when compared with other race/ethnic groups. The purpose of this review was to suggest a model for explaining how skeletal muscle fiber type may contribute to reduced aerobic capacity and obesity among non-Hispanic Black subjects. Our review indicates that metabolic properties of type II skeletal muscle (e.g. reduced oxidative capacity, capillary density) are related to various cardiometabolic diseases. Based on the review, non-Hispanic Black subjects appear to have a lower maximal aerobic capacity and a greater percentage of type II skeletal muscle fibers. Combined with reduced energy expenditure and reduced hemoglobin concentration, non-Hispanic Black subjects may be inherently predisposed to a reduced maximal aerobic capacity compared with non-Hispanic White subjects, thereby increasing the risk for obesity and related metabolic diseases.

  12. 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.

  13. Metabolic effects of glycerol supplementation and aerobic physical training on Wistar rats.

    PubMed

    Andrade, Eric Francelino; Lobato, Raquel Vieira; Araújo, Ticiana Vasques; Orlando, Débora Ribeiro; Gomes, Núbia Ferreira; Alvarenga, Renata Ribeiro; Rogatto, Gustavo Puggina; Zangeronimo, Márcio Gilberto; Pereira, Luciano José

    2014-09-01

    We evaluated the effects of oral glycerol supplementation on trained rats fed a normal diet. Wistar rats were distributed among 6 groups in a completely randomized 2 × 3 factorial design. The animals were subjected to 6 weeks of aerobic training. In the last 4 weeks, the animals' diet was supplemented with saline, glucose, or glycerol. Data were subjected to one-way analysis of variance (ANOVA) followed by a Student-Newmann-Keuls test, with values for P < 0.05 considered statistically significant. The change in body mass was lower in the trained groups, and their food and water consumption were higher. Glycerol supplementation resulted in an increase in the levels of triacylglycerol (TAG) and total cholesterol, as well as in the area and diameter of adipocytes. When associated with training, these parameters were similar to those of other trained groups. Levels of low-density lipoprotein + very-low-density lipoprotein cholesterol decreased in the trained animals that received glycerol compared with the non-trained ones. Glycerol consumption caused a reduction in food intake and increased the villous:crypt (V:C) ratio. No changes in glycemia, high density lipoproteins, or density of adipocytes were observed. Supplementation with glycerol together with aerobic physical training promoted beneficial metabolic effects. However, in non-trained rats glycerol increased the diameter and area of adipocytes, as well as the levels of TAG and total cholesterol.

  14. Effect of selected monoterpenes on methane oxidation, denitrification, and aerobic metabolism by bacteria in pure culture.

    PubMed

    Amaral, J A; Ekins, A; Richards, S R; Knowles, R

    1998-02-01

    Selected monoterpenes inhibited methane oxidation by methanotrophs (Methylosinus trichosporium OB3b, Methylobacter luteus), denitrification by environmental isolates, and aerobic metabolism by several heterotrophic pure cultures. Inhibition occurred to various extents and was transient. Complete inhibition of methane oxidation by Methylosinus trichosporium OB3b with 1.1 mM (-)-alpha-pinene lasted for more than 2 days with a culture of optical density of 0.05 before activity resumed. Inhibition was greater under conditions under which particulate methane monooxygenase was expressed. No apparent consumption or conversion of monoterpenes by methanotrophs was detected by gas chromatography, and the reason that transient inhibition occurs is not clear. Aerobic metabolism by several heterotrophs was much less sensitive than methanotrophy was; Escherichia coli (optical density, 0.01), for example, was not affected by up to 7.3 mM (-)-alpha-pinene. The degree of inhibition was monoterpene and species dependent. Denitrification by isolates from a polluted sediment was not inhibited by 3.7 mM (-)-alpha-pinene, gamma-terpinene, or beta-myrcene, whereas 50 to 100% inhibition was observed for isolates from a temperate swamp soil. The inhibitory effect of monoterpenes on methane oxidation was greatest with unsaturated, cyclic hydrocarbon forms [e.g., (-)-alpha-pinene, (S)-(-)-limonene, (R)-(+)-limonene, and gamma-terpinene]. Lower levels of inhibition occurred with oxide and alcohol derivatives [(R)-(+)-limonene oxide, alpha-pinene oxide, linalool, alpha-terpineol] and a noncyclic hydrocarbon (beta-myrcene). Isomers of pinene inhibited activity to different extents. Given their natural sources, monoterpenes may be significant factors affecting bacterial activities in nature.

  15. Antioxidants, metabolic rate and aging in Drosophila.

    PubMed

    Miquel, J; Fleming, J; Economos, A C

    1982-09-01

    In line with the (metabolic) rate-of-living theory of aging, previous work from this laboratory showed that the life-prolonging effect of the antioxidant thiazolidine carboxylic acid (TCA) in Drosophila was paralleled by a similar reduction of the oxygen consumption rate of the flies. To assess the generality of this phenomenon, several life-prolonging antioxidants were dietarily administered to the flies (in standard medium with 1% w/v of tocopherol-stripped corn oil) and their effects on metabolic rate and life span were determined. Respiration rate of groups of continuously agitated flies was measured in the Gilson respirometer. The studied antioxidants were as follows: (the numbers in parentheses are consecutively the antioxidant concentration in the medium in % wt/vol.; mean life span in days; and metabolic rate in microliter O2/mg fly per 24 h): vitamin E (0.4; 46.3; 58.5); 2,4-dinitrophenol (0.1; 45.7; 66.2); nordihydroguaiaretic acid (0.5; 45.6; 69.1); thiazolidine carboxylic acid (0.3; 53.1; 55.8); and control with no antioxidant added (0; 40.7; 73.3). All of these antioxidants at the tested concentrations reduced oxygen consumption rate and increased mean life span; there was a significant negative linear correlation (r = -0.87) between mean life span and metabolic rate. These data suggest that some antioxidants may inhibit respiration rate in addition to their protective effect against free radical-induced cellular damage.

  16. Alterations in aerobic-anaerobic proportions of metabolism during work in heat.

    PubMed

    Dimri, G P; Malhotra, M S; Sen Gupta, J; Kumar, T S; Arora, B S

    1980-01-01

    With a view to investigating the aerobic and anaerobic proportions of oxygen supply during different grades of muscular activity in varying thermal stress, studies have been conducted on six young healthy Indians naturally acclimatized to heat. The subjects were given submaximal exercises of 400, 500, and 600 kgm/min (equivalent to 65.40, 81.75, and 98.10 W) for 6 min on a bicycle ergometer in three different simulated conditions, i.e., comfortable, hot humid, and very hot humid. Their O2 consumption (VO2), pulmonary ventilation (VE) and heart rate (HR) were measured during rest and throughout the exercise period (6 min) and for 30 min post exercise. Blood lactate level (LA) was measured during rest and recovery. From these, the total O2 cost with aerobic and anaerobic proportions were calculated. Results indicated a significant increase in the total O2 cost for each exercise with increasing thermal stress, along with a significant increase in the anaerobic fraction and a decrease in the aerobic fraction. The increase in anaerobic contribution to the energy supply processes was further confirmed by a significant increase in relative O2 debt (l/kg) and in blood lactate level at each work load. Thus, a highly significant correlation (P < 0.001) was found between O2 debt contracted and increase in thermal stress. A significant fall in VO2 max was also observed in hot humid and very hot humid conditions as against comfortable temperature, with no change in HR max and VE max.

  17. Silvering and swimming effects on aerobic metabolism and reactive oxygen species in the European eel.

    PubMed

    Amérand, Aline; Mortelette, Hélène; Belhomme, Marc; Moisan, Christine

    2017-01-01

    Silvering, the last metamorphosis in the eel life cycle induces morphological and physiological modifications in yellow eels (sedentary stage). It pre-adapts them to cope with the extreme conditions they will encounter during their 6000-km spawning migration. A previous study showed that silver eels are able to cope with reactive oxygen species (ROS) over-production linked to an increase in aerobic metabolism during sustained swimming, but the question remains as to whether this mechanism is associated with silvering. A sustained swimming session decreased red muscle in vitro mitochondrial oxygen consumption (MO2) but increased ROS production in both eel stages. The swimming exercise used here was perhaps too intense to induce a stimulation of mitochondrial function or biogenesis even when antioxidant enzyme activities were unchanged. Pro-oxidant/antioxidant imbalance by lipid peroxidation increased in yellow but significantly decreased in silver eels. The silvering process therefore appears to allow a pre-adaptation of red muscle radical metabolism to the demands of spawning migration.

  18. Regulation and Function of Versatile Aerobic and Anaerobic Respiratory Metabolism in Pseudomonas aeruginosa

    PubMed Central

    Arai, Hiroyuki

    2011-01-01

    Pseudomonas aeruginosa is a ubiquitously distributed opportunistic pathogen that inhabits soil and water as well as animal-, human-, and plant-host-associated environments. The ubiquity would be attributed to its very versatile energy metabolism. P. aeruginosa has a highly branched respiratory chain terminated by multiple terminal oxidases and denitrification enzymes. Five terminal oxidases for aerobic respiration have been identified in the P. aeruginosa cells. Three of them, the cbb3-1 oxidase, the cbb3-2 oxidase, and the aa3 oxidase, are cytochrome c oxidases and the other two, the bo3 oxidase and the cyanide-insensitive oxidase, are quinol oxidases. Each oxidase has a specific affinity for oxygen, efficiency of energy coupling, and tolerance to various stresses such as cyanide and reactive nitrogen species. These terminal oxidases are used differentially according to the environmental conditions. P. aeruginosa also has a complete set of the denitrification enzymes that reduce nitrate to molecular nitrogen via nitrite, nitric oxide (NO), and nitrous oxide. These nitrogen oxides function as alternative electron acceptors and enable P. aeruginosa to grow under anaerobic conditions. One of the denitrification enzymes, NO reductase, is also expected to function for detoxification of NO produced by the host immune defense system. The control of the expression of these aerobic and anaerobic respiratory enzymes would contribute to the adaptation of P. aeruginosa to a wide range of environmental conditions including in the infected hosts. Characteristics of these respiratory enzymes and the regulatory system that controls the expression of the respiratory genes in the P. aeruginosa cells are overviewed in this article. PMID:21833336

  19. A new intra-aerobic metabolism in the nitrite-dependent anaerobic methane-oxidizing bacterium Candidatus 'Methylomirabilis oxyfera'.

    PubMed

    Wu, Ming L; Ettwig, Katharina F; Jetten, Mike S M; Strous, Marc; Keltjens, Jan T; van Niftrik, Laura

    2011-01-01

    Biological methane oxidation proceeds either through aerobic or anaerobic pathways. The newly discovered bacterium Candidatus 'Methylomirabilis oxyfera' challenges this dichotomy. This bacterium performs anaerobic methane oxidation coupled to denitrification, but does so in a peculiar way. Instead of scavenging oxygen from the environment, like the aerobic methanotrophs, or driving methane oxidation by reverse methanogenesis, like the methanogenic archaea in sulfate-reducing systems, it produces its own supply of oxygen by metabolizing nitrite via nitric oxide into oxygen and dinitrogen gas. The intracellularly produced oxygen is then used for the oxidation of methane by the classical aerobic methane oxidation pathway involving methane mono-oxygenase. The present mini-review summarizes the current knowledge about this process and the micro-organism responsible for it.

  20. Transport and metabolism of fumaric acid in Saccharomyces cerevisiae in aerobic glucose-limited chemostat culture.

    PubMed

    Shah, Mihir V; van Mastrigt, Oscar; Heijnen, Joseph J; van Gulik, Walter M

    2016-04-01

    Currently, research is being focused on the industrial-scale production of fumaric acid and other relevant organic acids from renewable feedstocks via fermentation, preferably at low pH for better product recovery. However, at low pH a large fraction of the extracellular acid is present in the undissociated form, which is lipophilic and can diffuse into the cell. There have been no studies done on the impact of high extracellular concentrations of fumaric acid under aerobic conditions in S. cerevisiae, which is a relevant issue to study for industrial-scale production. In this work we studied the uptake and metabolism of fumaric acid in S. cerevisiae in glucose-limited chemostat cultures at a cultivation pH of 3.0 (pH < pK). Steady states were achieved with different extracellular levels of fumaric acid, obtained by adding different amounts of fumaric acid to the feed medium. The experiments were carried out with the wild-type S. cerevisiae CEN.PK 113-7D and an engineered S. cerevisiae ADIS 244 expressing a heterologous dicarboxylic acid transporter (DCT-02) from Aspergillus niger, to examine whether it would be capable of exporting fumaric acid. We observed that fumaric acid entered the cells most likely via passive diffusion of the undissociated form. Approximately two-thirds of the fumaric acid in the feed was metabolized together with glucose. From metabolic flux analysis, an increased ATP dissipation was observed only at high intracellular concentrations of fumarate, possibly due to the export of fumarate via an ABC transporter. The implications of our results for the industrial-scale production of fumaric acid are discussed.

  1. Moderate and heavy metabolic stress interval training improve arterial stiffness and heart rate dynamics in humans.

    PubMed

    Rakobowchuk, Mark; Harris, Emma; Taylor, Annabelle; Cubbon, Richard M; Birch, Karen M

    2013-04-01

    Traditional continuous aerobic exercise training attenuates age-related increases of arterial stiffness, however, training studies have not determined whether metabolic stress impacts these favourable effects. Twenty untrained healthy participants (n = 11 heavy metabolic stress interval training, n = 9 moderate metabolic stress interval training) completed 6 weeks of moderate or heavy intensity interval training matched for total work and exercise duration. Carotid artery stiffness, blood pressure contour analysis, and linear and non-linear heart rate variability were assessed before and following training. Overall, carotid arterial stiffness was reduced (p < 0.01), but metabolic stress-specific alterations were not apparent. There was a trend for increased absolute high-frequency (HF) power (p = 0.10) whereas both absolute low-frequency (LF) power (p = 0.05) and overall power (p = 0.02) were increased to a similar degree following both training programmes. Non-linear heart rate dynamics such as detrended fluctuation analysis [Formula: see text] also improved (p > 0.05). This study demonstrates the effectiveness of interval training at improving arterial stiffness and autonomic function, however, the metabolic stress was not a mediator of this effect. In addition, these changes were also independent of improvements in aerobic capacity, which were only induced by training that involved a high metabolic stress.

  2. Short-Term Heart Rate Recovery is Related to Aerobic Fitness in Elite Intermittent Sport Athletes.

    PubMed

    Watson, Andrew M; Brickson, Stacey L; Prawda, Evan R; Sanfilippo, Jenifer L

    2017-04-01

    Watson, AM, Brickson, SL, Prawda, ER, and Sanfilippo, JL. Short-term heart rate recovery is related to aerobic fitness in elite intermittent sport athletes. J Strength Cond Res 31(4): 1055-1061, 2017-Although heart rate recovery (HRR) has been suggested as a measure of fitness, minimal data exist among athletes. The purpose of this study was to determine if HRR is related to aerobic fitness in elite athletes and whether this relationship is influenced by sex or body composition. Eighty-four collegiate athletes (45 male athletes) underwent body fat percentage (BF%) determination by dual-energy x-ray absorptiometry and maximal treadmill testing followed by 5 minutes of recovery. V[Combining Dot Above]O2max and heart rate (HRmax) were determined, and HRR was calculated as a percentage of HRmax at 10 seconds, 30 seconds, and 1, 2, 3, 4, and 5 minutes after test completion. After stratifying by sex, participants were grouped as high fit or low fit based on V[Combining Dot Above]O2max median split. Heart rate recovery was compared between sexes and fitness level at each time point. Multivariable regression analysis was used to identify independent predictors of HRR using V[Combining Dot Above]O2max, BF%, and sex as covariates. Heart rate recovery did not differ significantly between sexes and was faster among high-fit participants at 10 and 30 seconds, but at no other time. V[Combining Dot Above]O2max was significantly correlated with HRR at 10 and 30 seconds (r = -0.34, p < 0.001 and r = -0.28, p = 0.008) only. After controlling for BF% and sex, V[Combining Dot Above]O2max remained significantly associated with HRR at 10 seconds (p = 0.007) but not at 30 seconds (p = 0.067) or any time thereafter. Aerobic capacity is related to faster HRR during the first 30 seconds only, suggesting that only very short term HRR should be used as a measure of aerobic fitness in intermittent sport athletes.

  3. Quantum metabolism explains the allometric scaling of metabolic rates

    PubMed Central

    Demetrius, Lloyd; Tuszynski, J. A.

    2010-01-01

    A general model explaining the origin of allometric laws of physiology is proposed based on coupled energy-transducing oscillator networks embedded in a physical d-dimensional space (d = 1, 2, 3). This approach integrates Mitchell's theory of chemi-osmosis with the Debye model of the thermal properties of solids. We derive a scaling rule that relates the energy generated by redox reactions in cells, the dimensionality of the physical space and the mean cycle time. Two major regimes are found corresponding to classical and quantum behaviour. The classical behaviour leads to allometric isometry while the quantum regime leads to scaling laws relating metabolic rate and body size that cover a broad range of exponents that depend on dimensionality and specific parameter values. The regimes are consistent with a range of behaviours encountered in micelles, plants and animals and provide a conceptual framework for a theory of the metabolic function of living systems. PMID:19734187

  4. Quantum metabolism explains the allometric scaling of metabolic rates.

    PubMed

    Demetrius, Lloyd; Tuszynski, J A

    2010-03-06

    A general model explaining the origin of allometric laws of physiology is proposed based on coupled energy-transducing oscillator networks embedded in a physical d-dimensional space (d = 1, 2, 3). This approach integrates Mitchell's theory of chemi-osmosis with the Debye model of the thermal properties of solids. We derive a scaling rule that relates the energy generated by redox reactions in cells, the dimensionality of the physical space and the mean cycle time. Two major regimes are found corresponding to classical and quantum behaviour. The classical behaviour leads to allometric isometry while the quantum regime leads to scaling laws relating metabolic rate and body size that cover a broad range of exponents that depend on dimensionality and specific parameter values. The regimes are consistent with a range of behaviours encountered in micelles, plants and animals and provide a conceptual framework for a theory of the metabolic function of living systems.

  5. Effects of pulp and paper mill effluent extracts on liver anaerobic and aerobic metabolic enzymes in rainbow trout.

    PubMed

    Orrego, Rodrigo; Pandelides, Zacharias; Guchardi, John; Holdway, Douglas

    2011-05-01

    This study investigates whether pulse exposure to Chilean pulp and paper mill effluent solid phase extracted (SPE) extracts via intraperitoneal injection (IP), would result in changes in the activities of the respiratory metabolic enzymes citrate synthase (CS) and lactate dehydrogenase (LDH) in rainbow trout livers. It also investigated if an alteration in liver metabolic capacity influenced the liver detoxification processes and estrogenic effects previously reported. Besides, a comparison of those enzymatic activities with fish IP injected with SPE extracts of two model effluents coming from industries that process 100% different type of feedstock (softwood, SW and hardwood, HW) was also evaluated. An initial induction of the anaerobic metabolism (increase in LDH enzymatic activity) was detected in all Chilean pulp mill effluent extracts evaluated, contrary to the initial unaltered aerobic metabolism (CS enzymatic activity) observed. A compensatory relationship in energy metabolism (Pasteur effect) was observed when comparing both enzymatic activities of fish exposed to those effluent extracts. LDH and CS activities observed in fish injected with Chilean extracts seem to be related to the effects observed in fish injected with SW extracts. This study showed that intraperitoneal injection of pulp and paper mill effluent extracts affected the anaerobic and aerobic metabolic capacities in rainbow trout livers, but this metabolic alteration did not affect detoxification capability or estrogenic effect previously reported.

  6. Global Metabolic Stress of Isoeffort Continuous and High Intensity Interval Aerobic Exercise: A Comparative (1)H 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.

  7. Genetic correlations between basal and maximum metabolic rates in a wild rodent: consequences for evolution of endothermy.

    PubMed

    Sadowska, Edyta T; Labocha, Marta K; Baliga, Katarzyna; Stanisz, Anna; Wróblewska, Aleksandra K; Jagusiak, Wojciech; Koteja, Paweł

    2005-03-01

    According to the aerobic capacity model, endothermy in birds and mammals evolved as a correlated response to selection for an ability of sustained locomotor activity, rather than in a response to direct selection for thermoregulatory capabilities. A key assumption of the model is that aerobic capacity is functionally linked to basal metabolic rate (BMR). The assumption has been tested in several studies at the level of phenotypic variation among individuals or species, but none has provided a clear answer whether the traits are genetically correlated. Here we present results of a genetic analysis based on measurements of the basal and the maximum swim- and cold-induced oxygen consumption in about 1000 bank voles from six generations of a laboratory colony, reared from animals captured in the field. Narrow sense heritability (h2) was about 0.5 for body mass, about 0.4 for mass-independent basal and maximum metabolic rates, and about 0.3 for factorial aerobic scopes. Dominance genetic and common environmental (= maternal) effects were not significant. Additive genetic correlation between BMR and the swim-induced aerobic capacity was high and positive, whereas correlation resulting from specific-environmental effects was negative. However, BMR was not genetically correlated with the cold-induced aerobic capacity. The results are consistent with the aerobic capacity model of the evolution of endothermy in birds and mammals.

  8. 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

  9. 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.

  10. Effects of Rate-Limited Mass Transfer on Modeling Vapor Intrusion with Aerobic Biodegradation.

    PubMed

    Chen, Yiming; Hou, Deyi; Lu, Chunhui; Spain, Jim C; Luo, Jian

    2016-09-06

    Most of the models for simulating vapor intrusion accept the local equilibrium assumption for multiphase concentration distributions, that is, concentrations in solid, liquid and vapor phases are in equilibrium. For simulating vapor transport with aerobic biodegradation controlled by counter-diffusion processes, the local equilibrium assumption combined with dual-Monod kinetics and biomass decay may yield near-instantaneous behavior at steady state. The present research investigates how predicted concentration profiles and fluxes change as interphase mass transfer resistances are increased for vapor intrusion with aerobic biodegradation. Our modeling results indicate that the attenuation coefficients for cases with and without mass transfer limitations can be significantly different by orders of magnitude. Rate-limited mass transfer may lead to larger overlaps of contaminant vapor and oxygen concentrations, which cannot be simulated by instantaneous reaction models with local equilibrium mass transfer. In addition, the contaminant flux with rate-limited mass transfer is much smaller than that with local equilibrium mass transfer, indicating that local equilibrium mass transfer assumption may significantly overestimate the biodegradation rate and capacity for mitigating vapor intrusion through the unsaturated zone. Our results indicate a strong research need for field tests to examine the validity of local equilibrium mass transfer, a widely accepted assumption in modeling vapor intrusion.

  11. Relationships between metabolic rate, muscle electromyograms, and swim performance of adult chinook salmon

    SciTech Connect

    Geist, David R. ); Brown, Richard S. ); Cullinan, Valerie I. ); Mesa, Matthew G.; VanderKooi, S P.; McKinstry, Craig A. )

    2003-10-01

    We measured oxygen consumption rates of adult spring Chinook salmon and compared these values to other species of Pacific salmon. Our results indicated that adult salmon achieve their maximum level of oxygen consumption at about their upper critical swim speed. It is also at this speed that the majority of the energy supplied to the swimming fish switches from red muscle (powered by aerobic metabolism) to white muscle (powered by anaerobic metabolism). Determining the swimming performance of adult salmon will assist managers in developing fishways and other means to safely pass fish over hydroelectric dams and other man-made structures.

  12. Patterns of control of maximum metabolic rate in humans.

    PubMed

    Hochachka, Peter W; Beatty, Cheryl L

    2003-09-01

    In this analysis, four performance phenotypes were used to compare mechanisms of control of aerobic maximum metabolic rate (MMR): (i) untrained sedentary (US) subjects, as a reference group against which to compare (ii) power trained (PT), (iii) endurance trained (ET) and (iv) high altitude adapted native (HA) subject groups. Sprinters represented the PT group; long distance runners illustrated the ET group; and Quechuas represented the HA group. Numerous recent studies have identified contributors to control on both the adenosine triphosphate (ATP) supply side and the ATP demand side of ATP turnover. Control coefficients or c(i) values were defined as fractional change in MMR/fractional change in the capacity of any given step in ATP turnover. From the best available evidence it appears that at MMR all five of the major steps in energy delivery (namely, ventilation, pulmonary diffusion, cardiac output, tissue capillary - mitochondrial O(2) transfer, and aerobic cell metabolism per se) approach an upper functional ceiling, with control strength being distributed amongst the various O(2) flux steps. On the energy demand side, the situation is somewhat simplified since at MMR approximately 90% of O(2)-based ATP synthesis is used for actomyosin (AM) and Ca(2+) ATPases; at MMR these two ATP demand rates also appear to be near an upper functional ceiling. In consequence, at MMR the control contributions or c(i) values are rather evenly divided amongst all seven major steps in ATP supply and ATP demand pathways right to the point of fatigue. Relative to US (the reference group), in PT subjects at MMR control strength shifts towards O(2) delivery steps (ventilation, pulmonary diffusion and cardiac output). In contrast in ET and HA subjects at MMR control shifts towards the energy demand steps (AM and Ca(2+) ATPases), and more control strength is focussed on tissue level ATP supply and ATP demand. One obvious advantage of the ET and HA control pattern is improved

  13. Aerobic Exercise during Pregnancy and Presence of Fetal-Maternal Heart Rate Synchronization

    PubMed Central

    Van Leeuwen, Peter; Gustafson, Kathleen M.; Cysarz, Dirk; Geue, Daniel; May, Linda E.; Grönemeyer, Dietrich

    2014-01-01

    It has been shown that short-term direct interaction between maternal and fetal heart rates may take place and that this interaction is affected by the rate of maternal respiration. The aim of this study was to determine the effect of maternal aerobic exercise during pregnancy on the occurrence of fetal-maternal heart rate synchronization. Methods In 40 pregnant women at the 36th week of gestation, 21 of whom exercised regularly, we acquired 18 min. RR interval time series obtained simultaneously in the mothers and their fetuses from magnetocardiographic recordings. The time series of the two groups were examined with respect to their heart rate variability, the maternal respiratory rate and the presence of synchronization epochs as determined on the basis of synchrograms. Surrogate data were used to assess whether the occurrence of synchronization was due to chance. Results In the original data, we found synchronization occurred less often in pregnancies in which the mothers had exercised regularly. These subjects also displayed higher combined fetal-maternal heart rate variability and lower maternal respiratory rates. Analysis of the surrogate data showed shorter epochs of synchronization and a lack of the phase coordination found between maternal and fetal beat timing in the original data. Conclusion The results suggest that fetal-maternal heart rate coupling is present but generally weak. Maternal exercise has a damping effect on its occurrence, most likely due to an increase in beat-to-beat differences, higher vagal tone and slower breathing rates. PMID:25162592

  14. The Rate of Permafrost Carbon Release Under Aerobic and Anaerobic Decomposition

    NASA Astrophysics Data System (ADS)

    Lee, H.; Vogel, J. G.; Schuur, E. A.; Inglett, K. S.

    2008-12-01

    One of the ecological consequences caused by increased temperature in northern ecosystems is permafrost thawing. When ice-rich permafrost thaws, the land surface may develop lakes but could also drain, depending on the soil ice content and topographic position. More than 50% of terrestrial soil carbon is stored in the permafrost region, which may be subjected to faster decomposition due to permafrost thaw. As a result of thaw effects on hydrology, soil organic matter from permafrost may be deposited in an oxic or an anoxic environment after permafrost thaw. We tested how the oxygen status and soil substrate quality affect CO2 and CH4 emissions from permafrost soil by conducting laboratory soil incubation experiment. We measured CO2 emissions from aerobic incubations, and CO2 and CH4 from anaerobic incubations. Soil C to N ratios and enzyme activities (glucosidase, phosphatase, and aminopeptidase) were also analyzed to compare the organic matter quality of permafrost soils from different sites. The mass of C lost after 108 days of aerobic soil incubation ranged 0.06-7.98 mg C gdw-1 for mineral soil layers and 2.21-18.56 mg C gdw-1 for organic soil layers. In the anaerobic incubations, C loss in the form of CO2 emissions was 0.04-4.87 mg C gdw-1 while CH4 emissions were 0.00-0.23 mg C gdw- 1. The total C loss was about 3 times lower for the anaerobic soil incubations compared to the aerobic incubations. The carbon loss from CO2 emissions in aerobic incubation showed a linear relationship with C:N (R2=0.58). Overall, rates of C loss were 4-57 times higher in organic soils than mineral soils, which indicated the importance of substrate quality in the decomposition of permafrost carbon. The initial soil enzyme activities were higher in organic soils as compared to mineral soils for all the enzymes tested. Aminopeptidase activity was linearly correlated with C to N ratio (R2=0.78) and both phosphatase and glucosidase were exponentially correlated with %C (R2

  15. Similar hypotensive effects of combined aerobic and resistance exercise with 1 set versus 3 sets in women with metabolic syndrome.

    PubMed

    Tibana, Ramires A; Nascimento, Dahan da C; de Sousa, Nuno M F; de Almeida, Jeeser A; Moraes, Milton R; Durigan, João Luiz Quagliotti; Collier, Scott R; Prestes, Jonato

    2015-11-01

    The aim of the present study was to compare the response of systolic blood pressure (SBP), mean blood pressure (MBP) and diastolic blood pressure (DBP) following combined training with 1 set or with 3 sets of resistance exercise (RE). Sixteen women with metabolic syndrome (MetS) were randomly assigned to perform two combined exercise protocols and a control session (CON): 1-set, 30 min of aerobic exercise (AE) at 65-70% of reserve heart rate and 1 set of 8-12 repetitions at 80% of 10-RM in six resistance exercises; 3-sets, same protocol but with 3 sets; and CON, 30 min of seated rest. The SBP, MBP and DBP were measured before and every 15 min during 90 min following the experimental sessions. The SBP displayed a decrease (P ≤ 0.05) during the 90 min following the RE session with 1-set and 3-set, while MBP was decreased (P ≤ 0.05) up to 75 min after 1-set and up to 30 min after the 3-set exercise session compared with pre-intervention values. There was a decrease in DBP only for the greatest individual decrease following 1-set (-6.1 mmHg) and 3-set (-4.9 mmHg) combined exercise sessions, without differences between them. The rate-pressure product and heart rate remained significantly higher (P ≤ 0.05) 75 min and 90 min after the combined exercise session with 1- and 3-sets compared with the CON, respectively. In conclusion, a low-volume RE combined with AE resulted in similar decrease of SBP when compared with RE with 3-sets in women with MetS, which could be beneficial in situations of limited time.

  16. A rapid in situ respiration test for measuring aerobic biodegradation rates of hydrocarbons in soil

    SciTech Connect

    Hinchee, R.E.; Ong, S.K. )

    1992-10-01

    A in situ test method to measure the aerobic biodegradation rates of hydrocarbons in contaminated soil is presented. The test method provides an initial assessment of bioventing as a remediation technology for hydrocarbon-contaminated soil. The in situ respiration test consists of ventilating the contaminated soil of the unsaturated zone with air and periodically monitoring the depletion of oxygen (O[sub 2]) and production of carbon dioxide (CO[sub 2]) over time after the air is turned off. The test is simple to implement and generally takes about four to five days to complete. The test was applied at eight hydrocarbon-contaminated sites of different geological and climatic conditions. These sites were contaminated with petroleum products or petroleum fuels, except for two sites where the contaminants were primarily polycyclic aromatic hydrocarbons. Oxygen utilization rates for the eight sites ranged from 0.02 to 0.99 percent O[sub 2]/hour. Estimated biodegradation rates ranged from 0.4 to 19 mg/kg of soil/day. These rates were similar to the biodegradation rates obtained from field and pilot studies using mass balance methods. Estimated biodegradation rates based on O[sub 2] utilization were generally more reliable (especially for alkaline soils) than rates based on CO[sub 2] production, CO[sub 2] produced from microbial respiration was probably converted to carbonate under alkaline conditions. 14 refs., 5 figs., 4 tabs.

  17. A rapid in situ respiration test for measuring aerobic biodegradation rates of hydrocarbons in soil.

    PubMed

    Hinchee, R E; Ong, S K

    1992-10-01

    An in situ test method to measure the aerobic biodegradation rates of hydrocarbons in contaminated soil is presented. The test method provides an initial assessment of bioventing as a remediation technology for hydrocarbon-contaminated soil. The in situ respiration test consists of ventilating the contaminated soil of the unsaturated zone with air and periodically monitoring the depletion of oxygen (O2) and production of carbon dioxide (CO2) over time after the air is turned off. The test is simple to implement and generally takes about four to five days to complete. The test was applied at eight hydrocarbon-contaminated sites of different geological and climatic conditions. These sites were contaminated with petroleum products or petroleum fuels, except for two sites where the contaminants were primarily polycyclic aromatic hydrocarbons. Oxygen utilization rates for the eight sites ranged from 0.02 to 0.99 percent O2/hour. Estimated biodegradation rates ranged from 0.4 to 19 mg/kg of soil/day. These rates were similar to the biodegradation rates obtained from field and pilot studies using mass balance methods. Estimated biodegradation rates based on O2 utilization were generally more reliable (especially for alkaline soils) than rates based on CO2 production. CO2 produced from microbial respiration was probably converted to carbonate under alkaline conditions.

  18. Metabolic reprogramming towards aerobic glycolysis correlates with greater proliferative ability and resistance to metabolic inhibition in CD8 versus CD4 T cells.

    PubMed

    Cao, Yilin; Rathmell, Jeffrey C; Macintyre, Andrew N

    2014-01-01

    T lymphocytes (T cells) undergo metabolic reprogramming after activation to provide energy and biosynthetic materials for growth, proliferation and differentiation. Distinct T cell subsets, however, adopt metabolic programs specific to support their needs. As CD4 T cells coordinate adaptive immune responses while CD8 T cells become cytotoxic effectors, we compared activation-induced proliferation and metabolic reprogramming of these subsets. Resting CD4 and CD8 T cells were metabolically similar and used a predominantly oxidative metabolism. Following activation CD8 T cells proliferated more rapidly. Stimulation led both CD4 and CD8 T cells to sharply increase glucose metabolism and adopt aerobic glycolysis as a primary metabolic program. Activated CD4 T cells, however, remained more oxidative and had greater maximal respiratory capacity than activated CD8 T cells. CD4 T cells were also associated with greater levels of ROS and increased mitochondrial content, irrespective of the activation context. CD8 cells were better able, however, to oxidize glutamine as an alternative fuel source. The more glycolytic metabolism of activated CD8 T cells correlated with increased capacity for growth and proliferation, along with reduced sensitivity of cell growth to metabolic inhibition. These specific metabolic programs may promote greater growth and proliferation of CD8 T cells and enhance survival in diverse nutrient conditions.

  19. Genetic Analysis of a Rat Model of Aerobic Capacity and Metabolic Fitness

    PubMed Central

    Ren, Yu-yu; Overmyer, Katherine A.; Qi, Nathan R.; Treutelaar, Mary K.; Heckenkamp, Lori; Kalahar, Molly; Koch, Lauren G.; Britton, Steven L.; Burant, Charles F.; Li, Jun Z.

    2013-01-01

    Aerobic capacity is a strong predictor of all-cause mortality and can influence many complex traits. To explore the biological basis underlying this connection, we developed via artificial selection two rat lines that diverge for intrinsic (i.e. inborn) aerobic capacity and differ in risk for complex disease traits. Here we conduct the first in-depth pedigree and molecular genetic analysis of these lines, the high capacity runners (HCR) and low capacity runners (LCR). Our results show that both HCR and LCR lines maintain considerable narrow-sense heritability (h2) for the running capacity phenotype over 28 generations (h2 = 0.47 ± 0.02 and 0.43 ± 0.02, respectively). To minimize inbreeding, the lines were maintained by rotational mating. Pedigree records predict that the inbreeding coefficient increases at a rate of <1% per generation, ~37-38% slower than expected for random mating. Genome-wide 10K SNP genotype data for generations 5, 14, and 26 demonstrate substantial genomic evolution: between-line differentiation increased progressively, while within-line diversity deceased. Genome-wide average heterozygosity decreased at a rate of <1% per generation, consistent with pedigree-based predictions and confirming the effectiveness of rotational breeding. Linkage disequilibrium index r2 decreases to 0.3 at ~3 Mb, suggesting that the resolution for mapping quantitative trait loci (QTL) can be as high as 2-3 cM. To establish a test population for QTL mapping, we conducted an HCR-LCR intercross. Running capacity of the F1 population (n=176) was intermediate of the HCR and LCR parentals (28 pairs); and the F2 population (n=645) showed a wider range of phenotypic distribution. Importantly, heritability in the F0-F2 pedigree remained high (h2~0.6). These results suggest that the HCR-LCR lines can serve as a valuable system for studying genomic evolution, and a powerful resource for mapping QTL for a host of characters relevant to human health. PMID:24147032

  20. Do method and species lifestyle affect measures of maximum metabolic rate in fishes?

    PubMed

    Killen, S S; Norin, T; Halsey, L G

    2017-03-01

    The rate at which active animals can expend energy is limited by their maximum aerobic metabolic rate (MMR). Two methods are commonly used to estimate MMR as oxygen uptake in fishes, namely during prolonged swimming or immediately following brief exhaustive exercise, but it is unclear whether they return different estimates of MMR or whether their effectiveness for estimating MMR varies among species with different lifestyles. A broad comparative analysis of MMR data from 121 fish species revealed little evidence of different results between the two methods, either for fishes in general or for species of benthic, benthopelagic or pelagic lifestyles.

  1. Aerobic and anaerobic metabolism in oxygen minimum layer fishes: the role of alcohol dehydrogenase.

    PubMed

    Torres, Joseph J; Grigsby, Michelle D; Clarke, M Elizabeth

    2012-06-01

    Zones of minimum oxygen form at intermediate depth in all the world's oceans as a result of global circulation patterns that keep the water at oceanic mid-depths out of contact with the atmosphere for hundreds of years. In areas where primary production is very high, the microbial oxidation of sinking organic matter results in very low oxygen concentrations at mid-depths. Such is the case with the Arabian Sea, with O(2) concentrations reaching zero at 200 m and remaining very low (<0.1 ml O(2)l(-1)) for hundreds of meters below this depth, and in the California borderland, where oxygen levels reach 0.2 ml O(2)l(-1) at 700 m with severely hypoxic (<1.0 ml O(2)l(-1)) waters at depths 300 m above and below that. Despite the very low oxygen, mesopelagic fishes (primarily lanternfishes: Mytophidae) inhabiting the Arabian Sea and California borderland perform a daily vertical migration into the low-oxygen layer, spending daylight hours in the oxygen minimum zone and migrating upward into normoxic waters at night. To find out how fishes were able to survive their daily sojourns into the minimum zone, we tested the activity of four enzymes, one (lactate dehydrogenase, LDH) that served as a proxy for anaerobic glycolysis with a conventional lactate endpoint, a second (citrate synthase, CS) that is indicative of aerobic metabolism, a third (malate dehydrogenase) that functions in the Krebs' cycle and as a bridge linking mitochondrion and cytosol, and a fourth (alcohol dehydrogenase, ADH) that catalyzes the final reaction in a pathway where pyruvate is reduced to ethanol. Ethanol is a metabolic product easily excreted by fish, preventing lactate accumulation. The ADH pathway is rarely very active in vertebrate muscle; activity has previously been seen only in goldfish and other cyprinids capable of prolonged anaerobiosis. Activity of the enzyme suite in Arabian Sea and California fishes was compared with that of ecological analogs in the same family and with the same

  2. 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.

  3. Comprehensive analysis of glucose and xylose metabolism in Escherichia coli under aerobic and anaerobic conditions by (13)C metabolic flux analysis.

    PubMed

    Gonzalez, Jacqueline E; Long, Christopher P; Antoniewicz, Maciek R

    2017-01-01

    Glucose and xylose are the two most abundant sugars derived from the breakdown of lignocellulosic biomass. While aerobic glucose metabolism is relatively well understood in E. coli, until now there have been only a handful of studies focused on anaerobic glucose metabolism and no (13)C-flux studies on xylose metabolism. In the absence of experimentally validated flux maps, constraint-based approaches such as MOMA and RELATCH cannot be used to guide new metabolic engineering designs. In this work, we have addressed this critical gap in current understanding by performing comprehensive characterizations of glucose and xylose metabolism under aerobic and anaerobic conditions, using recent state-of-the-art techniques in (13)C metabolic flux analysis ((13)C-MFA). Specifically, we quantified precise metabolic fluxes for each condition by performing parallel labeling experiments and analyzing the data through integrated (13)C-MFA using the optimal tracers [1,2-(13)C]glucose, [1,6-(13)C]glucose, [1,2-(13)C]xylose and [5-(13)C]xylose. We also quantified changes in biomass composition and confirmed turnover of macromolecules by applying [U-(13)C]glucose and [U-(13)C]xylose tracers. We demonstrated that under anaerobic growth conditions there is significant turnover of lipids and that a significant portion of CO2 originates from biomass turnover. Using knockout strains, we also demonstrated that β-oxidation is critical for anaerobic growth on xylose. Quantitative analysis of co-factor balances (NADH/FADH2, NADPH, and ATP) for different growth conditions provided new insights regarding the interplay of energy and redox metabolism and the impact on E. coli cell physiology.

  4. Effects of chronic dietary selenomethionine exposure on repeat swimming performance, aerobic metabolism and methionine catabolism in adult zebrafish (Danio rerio).

    PubMed

    Thomas, Jith K; Wiseman, Steve; Giesy, John P; Janz, David M

    2013-04-15

    In a previous study we reported impaired swimming performance and greater stored energy in adult zebrafish (Danio rerio) after chronic dietary exposure to selenomethionine (SeMet). The goal of the present study was to further investigate effects of chronic exposure to dietary SeMet on repeat swimming performance, oxygen consumption (MO2), metabolic capacities (standard metabolic rate [SMR], active metabolic rate [AMR], factorial aerobic scope [F-AS] and cost of transport [COT]) and gene expression of energy metabolism and methionine catabolism enzymes in adult zebrafish. Fish were fed SeMet at measured concentrations of 1.3, 3.4, 9.8 or 27.5 μg Se/g dry mass (d.m.) for 90 d. At the end of the exposure period, fish from each treatment group were divided into three subgroups: (a) no swim, (b) swim, and (c) repeat swim. Fish from the no swim group were euthanized immediately at 90 d and whole body triglycerides, glycogen and lactate, and gene expression of energy metabolism and methionine catabolism enzymes were determined. Individual fish from the swim group were placed in a swim tunnel respirometer and swimming performance was assessed by determining the critical swimming speed (U(crit)). After both Ucrit and MO2 analyses, fish were euthanized and whole body energy stores and lactate were determined. Similarly, individual fish from the repeat swim group were subjected to two U(crit) tests (U(crit-1) and U(crit-2)) performed with a 60 min recovery period between tests, followed by determination of energy stores and lactate. Impaired swim performance was observed in fish fed SeMet at concentrations greater than 3 μg Se/g in the diet. However, within each dietary Se treatment group, no significant differences between single and repeat U(crits) were observed. Oxygen consumption, SMR and COT were significantly greater, and F-AS was significantly lesser, in fish fed SeMet. Whole body triglycerides were proportional to the concentration of SeMet in the diet. While

  5. Initial Molecular-Level Response to Artificial Selection for Increased Aerobic Metabolism Occurs Primarily through Changes in Gene Expression.

    PubMed

    Konczal, Mateusz; Babik, Wiesław; Radwan, Jacek; Sadowska, Edyta T; Koteja, Paweł

    2015-06-01

    Experimental evolution combined with genome or transcriptome resequencing (Evolve and Resequence) represents a promising approach for advancing our understanding of the genetic basis of adaptation. Here, we applied this strategy to investigate the effect of selection on a complex trait in lines derived from a natural population of a small mammal. We analyzed the liver and heart transcriptomes of bank voles (Myodes [=Clethrionomys] glareolus) that had been selected for increased aerobic metabolism. The organs were sampled from 13th generation voles; at that point, the voles from four replicate selected lines had 48% higher maximum rates of oxygen consumption than those from four control lines. At the molecular level, the response to selection was primarily observed in gene expression: Over 300 genes were found to be differentially expressed between the selected and control lines and the transcriptome-wide pattern of expression distinguished selected lines from controls. No evidence for selection-driven changes of allele frequencies at coding sites was found: No single nucleotide polymorphism (SNP) changed frequency more than expected under drift alone and frequency changes aggregated over all SNPs did not separate selected and control lines. Nevertheless, among genes which showed highest differentiation in allele frequencies between selected and control lines we identified, using information about gene functions and the biology of the selected phenotype, plausible targets of selection; these genes, together with those identified in expression analysis, have been prioritized for further studies. Because our selection lines were derived from a natural population, the amount and the spectrum of variation available for selection probably closely approximated that typically found in populations of small mammals. Therefore, our results are relevant to the understanding of the molecular basis of complex adaptations occurring in natural vertebrate populations.

  6. The Unified Parkinson's Disease Rating Scale as a predictor of peak aerobic capacity and ambulatory function.

    PubMed

    Ivey, Frederick M; Katzel, Leslie I; Sorkin, John D; Macko, Richard F; Shulman, Lisa M

    2012-01-01

    The Unified Parkinson's Disease Rating Scale (UPDRS) is a widely applied index of disease severity. Our objective was to assess the utility of UPDRS for predicting peak aerobic capacity (VO2 peak) and ambulatory function. Participants (n = 70) underwent evaluation for UPDRS (Total and Motor ratings), VO2 peak, 6-minute walk distance (6MW), and 30-foot self-selected walking speed (SSWS). Using regression, we determined the extent to which the Total and Motor UPDRS scores predicted each functional capacity measure after adjusting for age and sex. We also tested whether adding the Hoehn and Yahr scale (H-Y) to the model changed predictive power of the UPDRS. Adjusted for age and sex, both the Total UPDRS and Motor UPDRS subscale failed to predict VO2 peak. The Total UPDRS did weakly predict 6MW and SSWS (both p < 0.05), but the Motor UPDRS subscale did not predict these ambulatory function tests. After adding H-Y to the model, Total UPDRS was no longer an independent predictor of 6MW but remained a predictor of SSWS. We conclude that Total and Motor UPDRS rating scales do not predict VO2 peak, but that a weak relationship exists between Total UPDRS and measures of ambulatory function.

  7. Pseudomonas aeruginosa strain MA01 aerobically metabolizes the aminodinitrotoluenes produced by 2,4,6-trinitrotoluene nitro group reduction.

    PubMed

    Alvarez, M A; Kitts, C L; Botsford, J L; Unkefer, P J

    1995-11-01

    Many microbes reduce the nitro substituents of 2,4,6-trinitrotoluene (TNT), producing aminodinitrotoluenes (ADNTs). These compounds are recalcitrant to further breakdown and are acutely toxic. In a search for organisms capable of metabolizing ADNTs, a bacterial strain was isolated for the ability to use 2-aminobenzoate (anthranilate) as sole C-source. This isolate, Pseudomonas aeruginosa MA01, metabolized TNT by first reducing one nitro group to form either 2-amino-4,6-dinitrotoluene (2ADNT) or 4-amino-2,6-dinitrotoluene (4ADNT). However, strain MA01 was distinct from other TNT-reducing organisms in that it transformed these compounds into highly polar metabolites through an O2-dependent process. Strain MA01 was able to cometabolize TNT, 2ADNT, and 4ADNT in the presence of a variety of carbon and energy sources. During aerobic cometabolism with succinate, 45% of uniformly ring-labeled [14C]TNT was transformed to highly polar compounds. Aerobic cometabolism of purified [14C]2ADNT and [14C]4ADNT with succinate as C-source produced similar amounts of these polar metabolites. During O2-limited cometabolism with succinate as C-source and nitrate as electron acceptor, less than 8% of the [14C]TNT was transformed to polar metabolites. Purified 2,6-diamino-4-nitrotoluene was not metabolized, and while 2,4-diamino-6-nitrotoluene was acetylated, the product (N-acetyl-2,4-diamino-6-nitrotoluene) was not further metabolized. Therefore, strain MA01 metabolized TNT by oxidation of the ADNTs and not by reduction the remaining nitro groups on the ADNTs.

  8. Heart Rate Variability Correlates to Functional Aerobic Impairment in Hemodialysis Patients

    PubMed Central

    Carreira, Maria Angela Magalhães de Queiroz; Nogueira, André Barros; Pena, Felipe Montes; Kiuchi, Marcio Galindo; Rodrigues, Ronaldo Campos; Rodrigues, Rodrigo da Rocha; de Matos, Jorge Paulo Strogoff; Lugon, Jocemir Ronaldo

    2015-01-01

    Background Autonomic dysfunction (AD) is highly prevalent in hemodialysis (HD) patients and has been implicated in their increased risk of cardiovascular mortality. Objective To correlate heart rate variability (HRV) during exercise treadmill test (ETT) with the values obtained when measuring functional aerobic impairment (FAI) in HD patients and controls. Methods Cross-sectional study involving HD patients and a control group. Clinical examination, blood sampling, transthoracic echocardiogram, 24-hour Holter, and ETT were performed. A symptom-limited ramp treadmill protocol with active recovery was employed. Heart rate variability was evaluated in time domain at exercise and recovery periods. Results Forty-one HD patients and 41 controls concluded the study. HD patients had higher FAI and lower HRV than controls (p<0.001 for both). A correlation was found between exercise HRV (SDNN) and FAI in both groups. This association was independent of age, sex, smoking, body mass index, diabetes, and clonidine or beta-blocker use, but not of hemoglobin levels. Conclusion No association was found between FAI and HRV on 24-hour Holter or at the recovery period of ETT. Of note, exercise HRV was inversely correlated with FAI in HD patients and controls. PMID:26131705

  9. The determination of standard metabolic rate in fishes.

    PubMed

    Chabot, D; Steffensen, J F; Farrell, A P

    2016-01-01

    This review and data analysis outline how fish biologists should most reliably estimate the minimal amount of oxygen needed by a fish to support its aerobic metabolic rate (termed standard metabolic rate; SMR). By reviewing key literature, it explains the theory, terminology and challenges underlying SMR measurements in fishes, which are almost always made using respirometry (which measures oxygen uptake, ṀO2 ). Then, the practical difficulties of measuring SMR when activity of the fish is not quantitatively evaluated are comprehensively explored using 85 examples of ṀO2 data from different fishes and one crustacean, an analysis that goes well beyond any previous attempt. The main objective was to compare eight methods to estimate SMR. The methods were: average of the lowest 10 values (low10) and average of the 10% lowest ṀO2 values, after removing the five lowest ones as outliers (low10%), mean of the lowest normal distribution (MLND) and quantiles that assign from 10 to 30% of the data below SMR (q0·1 , q0·15 , q0·2 , q0·25 and q0·3 ). The eight methods yielded significantly different SMR estimates, as expected. While the differences were small when the variability was low amongst the ṀO2 values, they were important (>20%) for several cases. The degree of agreement between the methods was related to the c.v. of the observations that were classified into the lowest normal distribution, the c.v. MLND (C.V.MLND ). When this indicator was low (≤5·4), it was advantageous to use the MLND, otherwise, one of the q0·2 or q0·25 should be used. The second objective was to assess if the data recorded during the initial recovery period in the respirometer should be included or excluded, and the recommendation is to exclude them. The final objective was to determine the minimal duration of experiments aiming to estimate SMR. The results show that 12 h is insufficient but 24 h is adequate. A list of basic recommendations for practitioners who use respirometry

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  11. Female rats selectively bred for high intrinsic aerobic fitness are protected from ovariectomy-associated metabolic dysfunction

    PubMed Central

    Padilla, Jaume; Park, Young-Min; Welly, Rebecca J.; Scroggins, Rebecca J.; Britton, Steven L.; Koch, Lauren G.; Jenkins, Nathan T.; Crissey, Jacqueline M.; Zidon, Terese; Morris, E. Matthew; Meers, Grace M. E.; Thyfault, John P.

    2015-01-01

    Ovariectomized rodents model human menopause in that they rapidly gain weight, reduce spontaneous physical activity (SPA), and develop metabolic dysfunction, including insulin resistance. How contrasting aerobic fitness levels impacts ovariectomy (OVX)-associated metabolic dysfunction is not known. Female rats selectively bred for high and low intrinsic aerobic fitness [high-capacity runners (HCR) and low-capacity runners (LCR), respectively] were maintained under sedentary conditions for 39 wk. Midway through the observation period, OVX or sham (SHM) operations were performed providing HCR-SHM, HCR-OVX, LCR-SHM, and LCR-OVX groups. Glucose tolerance, energy expenditure, and SPA were measured before and 4 wk after surgery, while body composition via dual-energy X-ray absorptiometry and adipose tissue distribution, brown adipose tissue (BAT), and skeletal muscle phenotype, hepatic lipid content, insulin resistance via homeostatic assessment model of insulin resistance and AdipoIR, and blood lipids were assessed at death. Remarkably, HCR were protected from OVX-associated increases in adiposity and insulin resistance, observed only in LCR. HCR rats were ∼30% smaller, had ∼70% greater spontaneous physical activity (SPA), consumed ∼10% more relative energy, had greater skeletal muscle proliferator-activated receptor coactivator 1-alpha, and ∼40% more BAT. OVX did not increase energy intake and reduced SPA to the same extent in both HCR and LCR. LCR were particularly affected by an OVX-associated reduction in resting energy expenditure and experienced a reduction in relative BAT; resting energy expenditure correlated positively with BAT across all animals (r = 0.6; P < 0.001). In conclusion, despite reduced SPA following OVX, high intrinsic aerobic fitness protects against OVX-associated increases in adiposity and insulin resistance. The mechanism may involve preservation of resting energy expenditure. PMID:25608751

  12. Intraspecific Scaling of the Resting and Maximum Metabolic Rates of the Crucian Carp (Carassius auratus)

    PubMed Central

    Huang, Qingda; Zhang, Yurong; Liu, Shuting; Wang, Wen; Luo, Yiping

    2013-01-01

    The question of how the scaling of metabolic rate with body mass (M) is achieved in animals is unresolved. Here, we tested the cell metabolism hypothesis and the organ size hypothesis by assessing the mass scaling of the resting metabolic rate (RMR), maximum metabolic rate (MMR), erythrocyte size, and the masses of metabolically active organs in the crucian carp (Carassius auratus). The M of the crucian carp ranged from 4.5 to 323.9 g, representing an approximately 72-fold difference. The RMR and MMR increased with M according to the allometric equations RMR = 0.212M0.776 and MMR = 0.753M0.785. The scaling exponents for RMR (br) and MMR (bm) obtained in crucian carp were close to each other. Thus, the factorial aerobic scope remained almost constant with increasing M. Although erythrocyte size was negatively correlated with both mass-specific RMR and absolute RMR adjusted to M, it and all other hematological parameters showed no significant relationship with M. These data demonstrate that the cell metabolism hypothesis does not describe metabolic scaling in the crucian carp, suggesting that erythrocyte size may not represent the general size of other cell types in this fish and the metabolic activity of cells may decrease as fish grows. The mass scaling exponents of active organs was lower than 1 while that of inactive organs was greater than 1, which suggests that the mass scaling of the RMR can be partly due to variance in the proportion of active/inactive organs in crucian carp. Furthermore, our results provide additional evidence supporting the correlation between locomotor capacity and metabolic scaling. PMID:24376588

  13. Relationship of metabolic rate to body size in Orthoptera

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Metabolic rate determines an individual’s rate of resource acquisition, assimilation, growth, survival, and reproduction. Studies involving a broad range of taxa and body sizes typically result in whole-organism metabolic rate scaling to the ¾ power of body mass. Competing models have been proposed ...

  14. Is There a Chronic Elevation in Organ-Tissue Sleeping Metabolic Rate in Very Fit Runners?

    PubMed Central

    Midorikawa, Taishi; Tanaka, Shigeho; Ando, Takafumi; Tanaka, Chiaki; Masayuki, Konishi; Ohta, Megumi; Torii, Suguru; Sakamoto, Shizuo

    2016-01-01

    It is unclear whether the resting metabolic rate of individual organ-tissue in adults with high aerobic fitness is higher than that in untrained adults; in fact, this topic has been debated for years using a two-component model. To address this issue, in the present study, we examined the relationship between the measured sleeping energy expenditure (EE) by using an indirect human calorimeter (IHC) and the calculated resting EE (REE) from organ-tissue mass using magnetic resonance imaging, along with the assumed metabolic rate constants in healthy adults. Seventeen healthy male long-distance runners were recruited and grouped according to the median V·O2peak: very fit group (>60 mL/min/kg; n = 8) and fit group (<60 mL/min/kg; n = 9). Participants performed a graded exercise test for determining V·O2peak; X-ray absorptiometry and magnetic resonance imaging were used to determine organ-tissue mass, and IHC was used to determine sleeping EE. The calculated REE was estimated as the sum of individual organ-tissue masses multiplied by their metabolic rate constants. No significant difference was observed in the measured sleeping EE, calculated REE, and their difference, as well as in the slopes and intercepts of the two regression lines between the groups. Moreover, no significant correlation between V·O2peak and the difference in measured sleeping EE and calculated REE was observed for all subjects. Thus, aerobic endurance training does not result in a chronic elevation in the organ-tissue metabolic rate in cases with V·O2peak of approximately 60 mL/min/kg.

  15. Quantification of aerobic biodegradation and volatilization rates of gasoline hydrocarbons near the water table under natural attenuation conditions

    USGS Publications Warehouse

    Lahvis, M.A.; Baehr, A.L.; Baker, R.J.

    1999-01-01

    Aerobic biodegradation and volatilization near the water table constitute a coupled pathway that contributes significantly to the natural attenuation of hydrocarbons at gasoline spill sites. Rates of hydrocarbon biodegradation and volatilization were quantified by analyzing vapor transport in the unsaturated zone at a gasoline spill site in Beaufort, South Carolina. Aerobic biodegradation rates decreased with distance above the water table, ranging from 0.20 to 1.5g m-3 d-1 for toluene, from 0.24 to 0.38 g m-3 d-1 for xylene, from 0.09 to 0.24 g m-3 d-1 for cyclohexene, from 0.05 to 0.22 g m-3 d-1 for ethylbenzene, and from 0.02 to 0.08 g m-3 d-1 for benzene. Rates were highest in the capillary zone, where 68% of the total hydrocarbon mass that volatilized from the water table was estimated to have been biodegraded. Hydrocarbons were nearly completely degraded within 1 m above the water table. This large loss underscores the importance of aerobic biodegradation in limiting the transport of hydrocarbon vapors in the unsaturated zone and implies that vapor-plume migration to basements and other points of contact may only be significant if a source of free product is present. Furthermore, because transport of the hydrocarbon in the unsaturated zone can be limited relative to that of oxygen and carbon dioxide, soil, gas surveys conducted at hydrocarbon-spill sites would benefit by the inclusion of oxygen- and carbon-dioxide-gas concentration measurements. Aerobic degradation kinetics in the unsaturated zone were approximately first-order. First-order rate constants near the water table were highest for cyctohexene (0.21-0.65 d-1) and nearly equivalent for ethylbenzene (0.11-20.31 d-1), xylenes (0.10-0.31 d-1), toluene (0.09-0.30 d-1), and benzene (0.07,0.31 d-1). Hydrocarbon mass loss rates at the water table resulting from the coupled aerobic biodegradation and volatilization process were determined by extrapolating gas transport rates through the capillary zone. Mass

  16. Aerobic production of succinate from arabinose by metabolically engineered Corynebacterium glutamicum.

    PubMed

    Chen, Tao; Zhu, Nianqing; Xia, Huihua

    2014-01-01

    Arabinose is considered as an ideal feedstock for the microbial production of value-added chemicals due to its abundance in hemicellulosic wastes. In this study, the araBAD operon from Escherichia coli was introduced into succinate-producing Corynebacterium glutamicum, which enabled aerobic production of succinate using arabinose as sole carbon source. The engineered strain ZX1 (pXaraBAD, pEacsAgltA) produced 74.4 mM succinate with a yield of 0.58 mol (mol arabinose)(-1), which represented 69.9% of the theoretically maximal yield. Moreover, this strain produced 110.2 mM succinate using combined substrates of glucose and arabinose. To date, this is the highest succinate production under aerobic conditions in minimal medium.

  17. Aerobic metabolism and swimming energetics of the painted turtle, Chrysemys picta.

    PubMed

    Lowell, W R

    1990-01-01

    Oxygen consumption rates (VO2) were measured for painted turtles (Chrysemys picta) swimming in a respirometer at controlled speeds. Sustained specific swimming speeds ranged from 0.75 to 1.52 body lengths (L) per s. Over most of this range endurance exceeded 30 min. VO2 increased curvillinearly with swimming speed (U) and the maximum active rate was 9 times resting (0.26 ml O2/min), and 3 times routine (0.64 ml O2/min). Mass specific metabolic scope was 228 ml O2/(kg.h), similar to that reported for other active chelonians. Cost of transport increased from 3.86 to 5.72 J/(kg.m) over the speed range tested. Swimming costs for rowing painted turtles are greater than those for marine reptiles utilizing anguilliform or lift-producing hydrofoil propulsion. The increased swimming cost for the amphibious painted turtle suggests that morphological specializations permitting effective terrestrial transport, increase energetic expenditures during swimming.

  18. Evolution of basal metabolic rate in bank voles from a multidirectional selection experiment.

    PubMed

    Sadowska, Edyta T; Stawski, Clare; Rudolf, Agata; Dheyongera, Geoffrey; Chrząścik, Katarzyna M; Baliga-Klimczyk, Katarzyna; Koteja, Paweł

    2015-05-07

    A major theme in evolutionary and ecological physiology of terrestrial vertebrates encompasses the factors underlying the evolution of endothermy in birds and mammals and interspecific variation of basal metabolic rate (BMR). Here, we applied the experimental evolution approach and compared BMR in lines of a wild rodent, the bank vole (Myodes glareolus), selected for 11 generations for: high swim-induced aerobic metabolism (A), ability to maintain body mass on a low-quality herbivorous diet (H) and intensity of predatory behaviour towards crickets (P). Four replicate lines were maintained for each of the selection directions and an unselected control (C). In comparison to C lines, A lines achieved a 49% higher maximum rate of oxygen consumption during swimming, H lines lost 1.3 g less mass in the test with low-quality diet and P lines attacked crickets five times more frequently. BMR was significantly higher in A lines than in C or H lines (60.8, 56.6 and 54.4 ml O2 h(-1), respectively), and the values were intermediate in P lines (59.0 ml O2 h(-1)). Results of the selection experiment provide support for the hypothesis of a positive association between BMR and aerobic exercise performance, but not for the association of adaptation to herbivorous diet with either a high or low BMR.

  19. Evolution of basal metabolic rate in bank voles from a multidirectional selection experiment

    PubMed Central

    Sadowska, Edyta T.; Stawski, Clare; Rudolf, Agata; Dheyongera, Geoffrey; Chrząścik, Katarzyna M.; Baliga-Klimczyk, Katarzyna; Koteja, Paweł

    2015-01-01

    A major theme in evolutionary and ecological physiology of terrestrial vertebrates encompasses the factors underlying the evolution of endothermy in birds and mammals and interspecific variation of basal metabolic rate (BMR). Here, we applied the experimental evolution approach and compared BMR in lines of a wild rodent, the bank vole (Myodes glareolus), selected for 11 generations for: high swim-induced aerobic metabolism (A), ability to maintain body mass on a low-quality herbivorous diet (H) and intensity of predatory behaviour towards crickets (P). Four replicate lines were maintained for each of the selection directions and an unselected control (C). In comparison to C lines, A lines achieved a 49% higher maximum rate of oxygen consumption during swimming, H lines lost 1.3 g less mass in the test with low-quality diet and P lines attacked crickets five times more frequently. BMR was significantly higher in A lines than in C or H lines (60.8, 56.6 and 54.4 ml O2 h−1, respectively), and the values were intermediate in P lines (59.0 ml O2 h−1). Results of the selection experiment provide support for the hypothesis of a positive association between BMR and aerobic exercise performance, but not for the association of adaptation to herbivorous diet with either a high or low BMR. PMID:25876844

  20. Is the Polar F6 heart rate monitor less accurate during aerobic bench stepping because of arm movements?

    PubMed

    Lloyd, Lisa K; Crixell, Sylvia H; Price, Larry R

    2014-07-01

    Because of the well-documented linear relationship between heart rate and oxygen consumption (VO2), heart rate is commonly used to estimate energy expenditure during exercise. However, previous research suggests that heart rate increases without a concomitant rise in VO2 when arm movements are added to exercise. If so, this could impact the accuracy of heart rate monitors in estimating energy expenditure during combined arm and leg exercise. This study compared the cardiorespiratory responses to a bench step aerobics routine performed with and without arm movements and evaluated whether the accuracy of the Polar F6 heart rate monitor in predicting energy expenditure was impacted by the inclusion of arm movements. Thirty-two women performed the same routine with and without arm movements while stepping up and down off of a 15.24-cm bench at a cadence of 128 b·min-1. Heart rate and VO2 increased, whereas oxygen pulse (VO2·heart rate-1) decreased when arm movements were added (p < 0.001). However, the differences between the energy expenditure estimated by the Polar F6 heart rate monitor and the energy expenditure measured by indirect calorimetry were similar during the same aerobic bench stepping routine performed with and without arms (Δ∼2 kCal·min-1, p ≥ 0.05). Results confirm that arm movements during aerobic bench stepping elicit a disproportionate rise in heart rate relative to V[Combining Dot Above]O2. However, results do not support that these movements increase the prediction error in energy expenditure, as the Polar F6 heart rate monitor over predicted energy expenditure when arm movements were involved and when they were not involved.

  1. Caloric restriction, metabolic rate, and entropy.

    PubMed

    Demetrius, Lloyd

    2004-09-01

    Caloric restriction increases life span in many types of animals. This article proposes a mechanism for this effect based on the hypothesis that metabolic stability, the capacity of an organism to maintain steady state values of redox couples, is a prime determinant of longevity. We integrate the stability-longevity hypothesis with a molecular model of metabolic activity (quantum metabolism), and an entropic theory of evolutionary change (directionality theory), to propose a proximate mechanism and an evolutionary rationale for aging. The mechanistic features of the new theory of aging are invoked to predict that caloric restriction extends life span by increasing metabolic stability. The evolutionary model is exploited to predict that the large increases in life span under caloric restriction observed in rats, a species with early sexual maturity, narrow reproductive span and large litter size, and hence low entropy, will not hold for primates. We affirm that in the case of humans, a species with late sexual maturity, broad reproductive span and small litter size, and hence high entropy, the response of life span to caloric restriction will be negligible.

  2. Metabolic engineering of Escherichia coli for 1-butanol biosynthesis through the inverted aerobic fatty acid β-oxidation pathway.

    PubMed

    Gulevich, Andrey Yu; Skorokhodova, Alexandra Yu; Sukhozhenko, Alexey V; Shakulov, Rustem S; Debabov, Vladimir G

    2012-03-01

    The basic reactions of the clostridial 1-butanol biosynthesis pathway can be regarded to be the inverted reactions of the fatty acid β-oxidation pathway. A pathway for the biosynthesis of fuels and chemicals was recently engineered by combining enzymes from both aerobic and anaerobic fatty acid β-oxidation as well as enzymes from other metabolic pathways. In the current study, we demonstrate the inversion of the entire aerobic fatty acid β-oxidation cycle for 1-butanol biosynthesis. The constructed markerless and plasmidless Escherichia coli strain BOX-3 (MG1655 lacI(Q) attB-P(trc-ideal-4)-SD(φ10)-adhE(Glu568Lys) attB-P(trc-ideal-4)-SD(φ10)-atoB attB-P(trc-ideal-4)-SD(φ10)-fadB attB-P(trc-ideal-4)-SD(φ10)-fadE) synthesises 0.3-1 mg 1-butanol/l in the presence of the specific inducer. No 1-butanol production was detected in the absence of the inducer.

  3. Hexose metabolism in pancreatic islets. Regulation of aerobic glycolysis and pyruvate decarboxylation.

    PubMed

    Malaisse, W J; Rasschaert, J; Conget, I; Sener, A

    1991-01-01

    1. D-Glucose (0.5-16.7 mM) preferentially stimulates aerobic glycolysis and D-[3,4-14C]glucose oxidation, relative to D-[5-3H]glucose utilization in rat pancreatic islets, the concentration dependency of such a preferential effect displaying a sigmoidal pattern. 2. Inorganic and organic calcium antagonists, as well as Ca2+ deprivation, only cause a minor decrease in the ratio between D-[3,4-14C]glucose oxidation and D-[5-3H]glucose utilization in islets exposed to a high concentration of the hexose (16.7 mM). 3. Non-glucidic nutrient secretagogues such as 2-aminobicyclo[2,2,1]heptane-2-carboxylate (BCH), 2-ketoisocaproate and 3-phenylpyruvate fail to stimulate aerobic glycolysis and D-[3,4-14C]glucose oxidation in islets exposed to 6.0 mM D-glucose. Nevertheless, BCH augments [1-14C]pyruvate and [2-14C]pyruvate oxidation. 4. The glucose-induced increment in the paired ratio between D-[3,4-14C]glucose oxidation and D-[5-3H]glucose utilization is impaired in the presence of either cycloheximide or ouabain. 5. These findings suggest that the preferential effect of D-glucose upon aerobic glycolysis and pyruvate decarboxylation is not attributable solely to a Ca(2+)-induced activation of FAD-linked glycerophosphate dehydrogenase and/or pyruvate dehydrogenase, but may also involve an ATP-modulated regulatory process.

  4. Simulating the effect of aerobic biodegradation on soil vapor intrusion into buildings: influence of degradation rate, source concentration, and depth.

    PubMed

    Abreu, Lilian D V; Johnson, Paul C

    2006-04-01

    Steady-state vapor intrusion scenarios involving aerobically biodegradable chemicals are studied using a three-dimensional multicomponent numerical model. In these scenarios, sources of aerobically biodegradable chemical vapors are placed at depths of 1-14 m beneath a 10 m x 10 m basement or slab-on-grade construction building, and the simultaneous transport and reaction of hydrocarbon and oxygen vapors are simulated. The results are presented as Johnson and Ettinger attenuation factors alpha (predicted indoor air hydrocarbon concentration/source vapor concentration), and normalized contour plots of hydrocarbon and oxygen concentrations. In addition to varying the vapor source depth, the effects of source concentration (2-200 mg chemical/L vapor) and oxygen-limited first-order reaction rates (0.018-1.8 h(-1)) are studied. Hydrocarbon inputs were specific to benzene, although the relevant properties are similar to those for a range of hydrocarbons of interest. Overall, the results suggest that aerobic biodegradation could play a significant role in reducing vapor intrusion into buildings (decreased alpha-values) relative to the no-biodegradation case, with the significance of aerobic biodegradation increasing with increasing vapor source depth, decreasing vapor source concentration, and increasing first-order biodegradation rate. In contrast to the no-biodegradation case, differences in foundation construction can be significant in some settings. The significance of aerobic biodegradation is directly related to the extent to which oxygen is capable of migrating beneath the foundation. For example, in the case of a basement scenario with a 200 mg/L vapor source located at 3 m bgs, oxygen is consumed before it can migrate beneath the foundation, so the attenuation factors for simulations with and without aerobic biodegradation are similar for all first-order rates studied. For the case of a 2 mg/L vapor source located at 8 m bgs, the oxygen is widely distributed

  5. Metabolic network analysis of DB1 melanoma cells: how much energy is derived from aerobic glycolysis?

    PubMed

    Shestov, A A; Mancuso, A; Leeper, D B; Glickson, J D

    2013-01-01

    A network model has been developed for analysis of tumor glucose metabolism from (13)C MRS isotope exchange kinetic data. Data were obtained from DB1 melanoma cells grown on polystyrene microcarrier beads contained in a 20-mm diameter perfusion chamber in a 9.4 T Varian NMR spectrometer; the cells were perfused with 26 mM [1,6-(13)C(2)]glucose under normoxic conditions and 37°C and monitored by (13)C NMR spectroscopy for 6 h. The model consists of ∼150 differential equations in the cumomer formalism describing glucose and lactate transport, glycolysis, TCA cycle, pyruvate cycling, the pentose shunt, lactate dehydrogenase, the malate-aspartate and glycerophosphate shuttles, and various anaplerotic pathways. The rate of oxygen consumption (CMRO(2)) was measured polarographically by monitoring differences in pO(2). The model was validated by excellent agreement between model predicted and experimentally measured values of CMRO(2) and glutamate pool size. Assuming a P/O ratio of 2.5 for NADH and 1.5 for FADH2, ATP production was estimated as 46% glycolytic and 54% mitochondrial based on average values of CMRO(2) and glycolytic flux (two experiments).

  6. Behavioral inference of diving metabolic rate in free-ranging leatherback turtles.

    PubMed

    Bradshaw, Corey J A; McMahon, Clive R; Hays, Graeme C

    2007-01-01

    Good estimates of metabolic rate in free-ranging animals are essential for understanding behavior, distribution, and abundance. For the critically endangered leatherback turtle (Dermochelys coriacea), one of the world's largest reptiles, there has been a long-standing debate over whether this species demonstrates any metabolic endothermy. In short, do leatherbacks have a purely ectothermic reptilian metabolic rate or one that is elevated as a result of regional endothermy? Recent measurements have provided the first estimates of field metabolic rate (FMR) in leatherback turtles using doubly labeled water; however, the technique is prohibitively expensive and logistically difficult and produces estimates that are highly variable across individuals in this species. We therefore examined dive duration and depth data collected for nine free-swimming leatherback turtles over long periods (up to 431 d) to infer aerobic dive limits (ADLs) based on the asymptotic increase in maximum dive duration with depth. From this index of ADL and the known mass-specific oxygen storage capacity (To(2)) of leatherbacks, we inferred diving metabolic rate (DMR) as To2/ADL. We predicted that if leatherbacks conform to the purely ectothermic reptilian model of oxygen consumption, these inferred estimates of DMR should fall between predicted and measured values of reptilian resting and field metabolic rates, as well as being substantially lower than the FMR predicted for an endotherm of equivalent mass. Indeed, our behaviorally derived DMR estimates (mean=0.73+/-0.11 mL O(2) min(-1) kg(-1)) were 3.00+/-0.54 times the resting metabolic rate measured in unrestrained leatherbacks and 0.50+/-0.08 times the average FMR for a reptile of equivalent mass. These DMRs were also nearly one order of magnitude lower than the FMR predicted for an endotherm of equivalent mass. Thus, our findings lend support to the notion that diving leatherback turtles are indeed ectothermic and do not demonstrate

  7. Aerobic Capacity, Physical Activity and Metabolic Risk Factors in Firefighters Compared with Police Officers and Sedentary Clerks

    PubMed Central

    Leischik, Roman; Foshag, Peter; Strauß, Markus; Littwitz, Henning; Garg, Pankaj; Dworrak, Birgit; Horlitz, Marc

    2015-01-01

    Background This study examined the association between the physical work environment and physiological performance measures, physical activity levels and metabolic parameters among German civil servants. A main focus in this study was to examine the group differences rather than measuring the absolute values in an occupational group. Methods We prospectively examined 198 male German civil servants (97 firefighters [FFs], 55 police officers [POs] and 46 sedentary clerks [SCs]). For each parameter, the groups were compared using a linear regression adjusted for age. Results The 97 FFs showed a similar maximal aerobic power (VO2max l/min) of 3.17±0.44 l/min compared with the POs, who had a maximal aerobic power of 3.13±0.62 l/min (estimated difference, POs vs. FFs: 0.05, CI: -0.12-0.23, p=0.553). The maximal aerobic power of the FFs was slightly higher than that of the SCs, who had a maximal aerobic power of 2.85±0.52 l/min (-0.21, CI: -0.39-0.04, p=0.018 vs. FFs). The average physical activity (in metabolic equivalents [METS]/week) of the FFs was 3818.8±2843.5, whereas those of the POs and SCs were 2838.2±2871.9 (-808.2, CI: 1757.6-141.2, p=0.095) and 2212.2±2292.8 (vs. FFs: -1417.1, CI: -2302-531.88, p=0.002; vs. POs: -2974.4, CI: -1611.2-393.5, p=0.232), respectively. For the FFs, the average body fat percentage was 17.7%±6.2, whereas it was 21.4%±5.6 for the POs (vs. FFs: 2.75, CI: 0.92-4.59, p=0.004) and 20.8%±6.5 for the SCs (vs. FFs: 1.98, CI: -0.28-4.25, p=0.086; vs. POs: -0.77, CI: 3.15-1.61, p=0.523). The average waist circumference was 89.8 cm±10.0 for the FFs, 97.8 cm±12.4 (5.63, CI: 2.10-9.15, p=0.002) for the POs, and 97.3±11.7 (vs. FFs: -4.89, CI: 1.24-8.55, p=0.009; vs. POs: -0.73, CI: -5.21-3.74, p=0.747) for the SCs. Conclusions The FFs showed significantly higher physical activity levels compared with the SCs. The PO group had the highest cardiovascular risk of all of the groups because it included more participants with metabolic

  8. Effect of dispersed crude oil exposure upon the aerobic metabolic scope in juvenile golden grey mullet (Liza aurata).

    PubMed

    Milinkovitch, Thomas; Lucas, Julie; Le Floch, Stéphane; Thomas-Guyon, Hélène; Lefrançois, Christel

    2012-04-01

    This study evaluated the toxicity of dispersant application which is, in nearshore area, a controversial response technique to oil spill. Through an experimental approach with juveniles of Liza aurata, the toxicity of five exposure conditions was evaluated: (i) a chemically dispersed oil simulating dispersant application; (ii) a single dispersant as an internal control of chemically dispersed oil; (iii) a mechanically dispersed oil simulating natural dispersion of oil; (iv) a water soluble fraction of oil simulating an undispersed and untreated oil slick and (v) uncontaminated seawater as a control exposure condition. The relative concentration of PAHs (polycyclic aromatic hydrocarbons) biliary metabolites showed that the incorporation of these toxic compounds was increased if the oil was dispersed, whether mechanically or chemically. However, toxicity was not observed at the organism level since the aerobic metabolic scope and the critical swimming speed of exposed fish were not impaired.

  9. The influence of Angiostrongylus cantonensis (Nematoda, Metastrongylidae) infection on the aerobic metabolism of Biomphalaria straminea and Biomphalaria tenagophila (Mollusca, Gastropoda).

    PubMed

    Lima, Mariana G; Tunholi-Alves, Vinícius M; Gaudêncio, Fabrício N; Martins, Florence G; Castro, Rosane N; Thiengo, Silvana C; Garcia, Juberlan S; Maldonado, Arnaldo; Pinheiro, Jairo

    2016-12-01

    Angiostrongylus cantonensis is considered the main agent responsible for human eosinophilic meningoencephalitis. This parasite has low specificity for mollusk hosts and it can also use aquatic snails as auxiliary hosts. Studies based on the metabolic profile of Biomphalaria spp. infected by A. cantonensis have been conducted to observe parasite-host interactions. In the present study, the glucose content in the hemolymph and glycogen content in the digestive gland and cephalopedal mass of Biomphalaria tenagophila and Biomphalaria straminea experimentally infected by A. cantonensis were evaluated, along with the activity of LDH. The snails were dissected from 6 to 21days after infection to collect the hemolymph and separate the tissues. Decreases of 96% and 6.4% in the glucose content triggered a transition from aerobic to anaerobic metabolism in the two infected snail species, B. straminea and B. tenagophila, respectively. That finding was confirmed by high-performance liquid chromatography. These results indicate that when infected, these snails are able to change their metabolic profile, suggesting a strategy to maintain their homeostatic balance.

  10. Validity of COSMED's quark CPET mixing chamber system in evaluating energy metabolism during aerobic exercise in healthy male adults.

    PubMed

    Nieman, David C; Austin, Melanie D; Dew, Dustin; Utter, Alan C

    2013-01-01

    This study validated the accuracy of COSMED's Quark cardiopulmonary exercise testing (CPET) metabolic mixing chamber system in measuring metabolic factors during maximal, graded exercise testing. Subjects included 32 physically active men between the ages of 18 and 34 years. During the first test session, subjects were measured for maximal oxygen consumption twice (15 min separation) with the CPET and Douglas bag systems (random order). During the second test session, subjects exercised through four stages of the Bruce treadmill protocol with measurement by the CPET and Douglas bag systems (random order) during steady state at the end of each 3-minute stage. Statistical analysis using a 2 (systems) x 5 (time) repeated measures ANOVA showed that the pattern of change in VO2, VCO2, VE, FeO2, FeCO2, and RER did not differ significantly between CPET and Douglas bag systems. This validation study indicates that the CPET mixing chamber system provides valid metabolic measurements that compare closely with the Douglas bag system during aerobic exercise.

  11. Constraint-Free Measurement of Metabolic Rate

    NASA Technical Reports Server (NTRS)

    Koester, K. L.

    1982-01-01

    By using hardware and software originally developed for manned spacecraft, metabolism is now measured while subject wears a loose-fitting mask. This more comfortable, less-restrictive measurement technique uses speed, accuracy and control capabilities of a microcomputer. Because mask imposes minimum interference to subject undergoing testing, it can be used to measure respiratory responses to such activities as treadmill exercise. Mask can be worn for long periods with little discomfort.

  12. Auxin metabolism rates and implications for plant development

    PubMed Central

    Kramer, Eric M.; Ackelsberg, Ethan M.

    2015-01-01

    Studies of auxin metabolism rarely express their results as a metabolic rate, although the data obtained would often permit such a calculation to be made. We analyze data from 31 previously published papers to quantify the rates of auxin biosynthesis, conjugation, conjugate hydrolysis, and catabolism in seed plants. Most metabolic pathways have rates in the range 10 nM/h–1 μM/h, with the exception of auxin conjugation, which has rates as high as ~100 μM/h. The high rates of conjugation suggest that auxin metabolic sinks may be very small, perhaps as small as a single cell. By contrast, the relatively low rate of auxin biosynthesis requires plants to conserve and recycle auxin during long-distance transport. The consequences for plant development are discussed. PMID:25852709

  13. 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.

  14. Effects of Aerobic Exercise on Postprandial Carbohydrate and Lipoprotein Metabolism Following Cookie Ingestion in Healthy Young Women.

    PubMed

    Hashimoto, Sayuki; Mizutani, Erika; Suzuki, Maiko; Yoshida, Akihiro; Naito, Michitaka

    2015-01-01

    We examined the acute effects of postprandial aerobic exercise on glucose and lipid metabolism following cookie ingestion. Fifteen healthy young women with a sedentary lifestyle, normal weight and apolipoprotein E3/3 participated. After a 12-h overnight fast, each subject ingested a cookie (1.53 g/kg, Meal Test C) and then performed two trials, one with postprandial exercise (E trial) and one without exercise (C trial), in a randomized crossover design. A single 30-min bout of walking exercise was performed 20 min after the cookie intake. Venous blood samples were drawn before (0 h) and 20 min and 1, 2, 4, and 6 h after cookie ingestion. The Δglucose concentration was not significantly different between the two trials, but the Δinsulin concentration at 1 h and the incremental area under the curve (IAUC) (0-2 h)-insulin in the E trial were significantly lower than in the C trial. The ratio of glucose/insulin at 1 h was significantly higher in the E trial than in the C trial. The ΔTG, ΔRLP-TG, ΔapoB48 and ΔRemL-C concentrations at 1 h in the E trial were significantly higher than in the C trial. The IAUC (0-2 h)-apoB48 in the E trial was significantly larger than in the C trial. Postprandial exercise showed an insulin-sparing effect following the cookie ingestion by increasing insulin sensitivity. However, postprandial exercise transiently stimulated the secretion of exogenous apoB48-containing lipoprotein during the early period, and no further effects were observed. These results suggest that postprandial aerobic exercise is effective for the promotion of postprandial carbohydrate metabolism, but not lipidemia.

  15. Genome Sequence of Azotobacter vinelandii, an Obligate Aerobe Specialized To Support Diverse Anaerobic Metabolic Processes▿ †

    PubMed Central

    Setubal, João C.; dos Santos, Patricia; Goldman, Barry S.; Ertesvåg, Helga; Espin, Guadelupe; Rubio, Luis M.; Valla, Svein; Almeida, Nalvo F.; Balasubramanian, Divya; Cromes, Lindsey; Curatti, Leonardo; Du, Zijin; Godsy, Eric; Goodner, Brad; Hellner-Burris, Kaitlyn; Hernandez, José A.; Houmiel, Katherine; Imperial, Juan; Kennedy, Christina; Larson, Timothy J.; Latreille, Phil; Ligon, Lauren S.; Lu, Jing; Mærk, Mali; Miller, Nancy M.; Norton, Stacie; O'Carroll, Ina P.; Paulsen, Ian; Raulfs, Estella C.; Roemer, Rebecca; Rosser, James; Segura, Daniel; Slater, Steve; Stricklin, Shawn L.; Studholme, David J.; Sun, Jian; Viana, Carlos J.; Wallin, Erik; Wang, Baomin; Wheeler, Cathy; Zhu, Huijun; Dean, Dennis R.; Dixon, Ray; Wood, Derek

    2009-01-01

    Azotobacter vinelandii is a soil bacterium related to the Pseudomonas genus that fixes nitrogen under aerobic conditions while simultaneously protecting nitrogenase from oxygen damage. In response to carbon availability, this organism undergoes a simple differentiation process to form cysts that are resistant to drought and other physical and chemical agents. Here we report the complete genome sequence of A. vinelandii DJ, which has a single circular genome of 5,365,318 bp. In order to reconcile an obligate aerobic lifestyle with exquisitely oxygen-sensitive processes, A. vinelandii is specialized in terms of its complement of respiratory proteins. It is able to produce alginate, a polymer that further protects the organism from excess exogenous oxygen, and it has multiple duplications of alginate modification genes, which may alter alginate composition in response to oxygen availability. The genome analysis identified the chromosomal locations of the genes coding for the three known oxygen-sensitive nitrogenases, as well as genes coding for other oxygen-sensitive enzymes, such as carbon monoxide dehydrogenase and formate dehydrogenase. These findings offer new prospects for the wider application of A. vinelandii as a host for the production and characterization of oxygen-sensitive proteins. PMID:19429624

  16. 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.

  17. Overexpression of a Water-Forming NADH Oxidase Improves the Metabolism and Stress Tolerance of Saccharomyces cerevisiae in Aerobic Fermentation

    PubMed Central

    Shi, Xinchi; Zou, Yanan; Chen, Yong; Zheng, Cheng; Ying, Hanjie

    2016-01-01

    Redox homeostasis is fundamental to the maintenance of metabolism. Redox imbalance can cause oxidative stress, which affects metabolism and growth. Water-forming NADH oxidase regulates the redox balance by oxidizing cytosolic NADH to NAD+, which relieves cytosolic NADH accumulation through rapid glucose consumption in Saccharomyces cerevisiae, thus decreasing the production of the by product glycerol in industrial ethanol production. Here, we studied the effects of overexpression of a water-forming NADH oxidase from Lactococcus lactis on the stress response of S. cerevisiae in aerobic batch fermentation, and we constructed an interaction network of transcriptional regulation and metabolic networks to study the effects of and mechanisms underlying NADH oxidase regulation. The oxidase-overexpressing strain (NOX) showed increased glucose consumption, growth, and ethanol production, while glycerol production was remarkably lower. Glucose was exhausted by NOX at 26 h, while 18.92 ± 0.94 g/L residual glucose was left in the fermentation broth of the control strain (CON) at this time point. At 29.5 h, the ethanol concentration for NOX peaked at 35.25 ± 1.76 g/L, which was 14.37% higher than that for CON (30.82 ± 1.54 g/L). Gene expression involved in the synthesis of thiamine, which is associated with stress responses in various organisms, was increased in NOX. The transcription factor HAP4 was significantly upregulated in NOX at the late-exponential phase, indicating a diauxic shift in response to starvation. The apoptosis-inducing factor Nuc1 was downregulated while the transcription factor Sok2, which regulates the production of the small signaling molecule ammonia, was upregulated at the late-exponential phase, benefiting young cells on the rim. Reactive oxygen species production was decreased by 10% in NOX, supporting a decrease in apoptosis. The HOG pathway was not activated, although the osmotic stress was truly higher, indicating improved osmotolerance. Thus

  18. 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;…

  19. Aerobic Toluene Degraders in the Rhizosphere of a Constructed Wetland Model Show Diurnal Polyhydroxyalkanoate Metabolism

    PubMed Central

    Lünsmann, Vanessa; Kappelmeyer, Uwe; Taubert, Anja; Nijenhuis, Ivonne; von Bergen, Martin; Müller, Jochen A.; Jehmlich, Nico

    2016-01-01

    ABSTRACT Constructed wetlands (CWs) are successfully applied for the treatment of waters contaminated with aromatic compounds. In these systems, plants provide oxygen and root exudates to the rhizosphere and thereby stimulate microbial degradation processes. Root exudation of oxygen and organic compounds depends on photosynthetic activity and thus may show day-night fluctuations. While diurnal changes in CW effluent composition have been observed, information on respective fluctuations of bacterial activity are scarce. We investigated microbial processes in a CW model system treating toluene-contaminated water which showed diurnal oscillations of oxygen concentrations using metaproteomics. Quantitative real-time PCR was applied to assess diurnal expression patterns of genes involved in aerobic and anaerobic toluene degradation. We observed stable aerobic toluene turnover by Burkholderiales during the day and night. Polyhydroxyalkanoate synthesis was upregulated in these bacteria during the day, suggesting that they additionally feed on organic root exudates while reutilizing the stored carbon compounds during the night via the glyoxylate cycle. Although mRNA copies encoding the anaerobic enzyme benzylsuccinate synthase (bssA) were relatively abundant and increased slightly at night, the corresponding protein could not be detected in the CW model system. Our study provides insights into diurnal patterns of microbial processes occurring in the rhizosphere of an aquatic ecosystem. IMPORTANCE Constructed wetlands are a well-established and cost-efficient option for the bioremediation of contaminated waters. While it is commonly accepted knowledge that the function of CWs is determined by the interplay of plants and microorganisms, the detailed molecular processes are considered a black box. Here, we used a well-characterized CW model system treating toluene-contaminated water to investigate the microbial processes influenced by diurnal plant root exudation. Our results

  20. Gravity, body mass and composition, and metabolic rate

    NASA Technical Reports Server (NTRS)

    Pace, N.; Smith, A. H.

    1984-01-01

    The scale effects of increased gravitational loading by chronic centrifugation on metabolic rate and body composition in metabolically mature mammals were investigated. Individual oxygen consumption rates in groups of 12 each, 8-month-old, hamster, rats, guinea pigs, and rabbits were measured at weekly intervals at 1.0 g, then 2.0 g for 6 weeks. Metabolic rate was increased significantly in all species, and stabilized after 2 weeks at 2.0 g. Statistical analysis of the data revealed that the larger the animal the greater was the increase in mass-specific metabolic rate, or metabolic intensity, over the 1.0 g value for the same animal, with the result that the interspecies allometric scaling relationship between metabolic rate and total body mass is different at 2.0 g compared 10 1.0 g. Analysis of covariance shows that the postioning constant at 2.0 g is increased by 17% at 2.0 g at the P .001 level, and the exponent is increased by 8% at the P = 0.008 level. Thus, the hypothesis that augmented gravitational loading should shift the allometric relationship between metabolic rate and body size by an increase in both parameters is supported.

  1. Palaeohistological Evidence for Ancestral High Metabolic Rate in Archosaurs.

    PubMed

    Legendre, Lucas J; Guénard, Guillaume; Botha-Brink, Jennifer; Cubo, Jorge

    2016-11-01

    Metabolic heat production in archosaurs has played an important role in their evolutionary radiation during the Mesozoic, and their ancestral metabolic condition has long been a matter of debate in systematics and palaeontology. The study of fossil bone histology provides crucial information on bone growth rate, which has been used to indirectly investigate the evolution of thermometabolism in archosaurs. However, no quantitative estimation of metabolic rate has ever been performed on fossils using bone histological features. Moreover, to date, no inference model has included phylogenetic information in the form of predictive variables. Here we performed statistical predictive modeling using the new method of phylogenetic eigenvector maps on a set of bone histological features for a sample of extant and extinct vertebrates, to estimate metabolic rates of fossil archosauromorphs. This modeling procedure serves as a case study for eigenvector-based predictive modeling in a phylogenetic context, as well as an investigation of the poorly known evolutionary patterns of metabolic rate in archosaurs. Our results show that Mesozoic theropod dinosaurs exhibit metabolic rates very close to those found in modern birds, that archosaurs share a higher ancestral metabolic rate than that of extant ectotherms, and that this derived high metabolic rate was acquired at a much more inclusive level of the phylogenetic tree, among non-archosaurian archosauromorphs. These results also highlight the difficulties of assigning a given heat production strategy (i.e., endothermy, ectothermy) to an estimated metabolic rate value, and confirm findings of previous studies that the definition of the endotherm/ectotherm dichotomy may be ambiguous.

  2. Aerobic respiration metabolism in lactic acid bacteria and uses in biotechnology.

    PubMed

    Pedersen, Martin B; Gaudu, Philippe; Lechardeur, Delphine; Petit, Marie-Agnès; Gruss, Alexandra

    2012-01-01

    The lactic acid bacteria (LAB) are essential for food fermentations and their impact on gut physiology and health is under active exploration. In addition to their well-studied fermentation metabolism, many species belonging to this heterogeneous group are genetically equipped for respiration metabolism. In LAB, respiration is activated by exogenous heme, and for some species, heme and menaquinone. Respiration metabolism increases growth yield and improves fitness. In this review, we aim to present the basics of respiration metabolism in LAB, its genetic requirements, and the dramatic physiological changes it engenders. We address the question of how LAB acquired the genetic equipment for respiration. We present at length how respiration can be used advantageously in an industrial setting, both in the context of food-related technologies and in novel potential applications.

  3. Metabolic rates of giant pandas inform conservation strategies

    PubMed Central

    Fei, Yuxiang; Hou, Rong; Spotila, James R.; Paladino, Frank V.; Qi, Dunwu; Zhang, Zhihe

    2016-01-01

    The giant panda is an icon of conservation and survived a large-scale bamboo die off in the 1980s in China. Captive breeding programs have produced a large population in zoos and efforts continue to reintroduce those animals into the wild. However, we lack sufficient knowledge of their physiological ecology to determine requirements for survival now and in the face of climate change. We measured resting and active metabolic rates of giant pandas in order to determine if current bamboo resources were sufficient for adding additional animals to populations in natural reserves. Resting metabolic rates were somewhat below average for a panda sized mammal and active metabolic rates were in the normal range. Pandas do not have exceptionally low metabolic rates. Nevertheless, there is enough bamboo in natural reserves to support both natural populations and large numbers of reintroduced pandas. Bamboo will not be the limiting factor in successful reintroduction. PMID:27264109

  4. Metabolic rates of giant pandas inform conservation strategies

    NASA Astrophysics Data System (ADS)

    Fei, Yuxiang; Hou, Rong; Spotila, James R.; Paladino, Frank V.; Qi, Dunwu; Zhang, Zhihe

    2016-06-01

    The giant panda is an icon of conservation and survived a large-scale bamboo die off in the 1980s in China. Captive breeding programs have produced a large population in zoos and efforts continue to reintroduce those animals into the wild. However, we lack sufficient knowledge of their physiological ecology to determine requirements for survival now and in the face of climate change. We measured resting and active metabolic rates of giant pandas in order to determine if current bamboo resources were sufficient for adding additional animals to populations in natural reserves. Resting metabolic rates were somewhat below average for a panda sized mammal and active metabolic rates were in the normal range. Pandas do not have exceptionally low metabolic rates. Nevertheless, there is enough bamboo in natural reserves to support both natural populations and large numbers of reintroduced pandas. Bamboo will not be the limiting factor in successful reintroduction.

  5. Metabolic rates of giant pandas inform conservation strategies.

    PubMed

    Fei, Yuxiang; Hou, Rong; Spotila, James R; Paladino, Frank V; Qi, Dunwu; Zhang, Zhihe

    2016-06-06

    The giant panda is an icon of conservation and survived a large-scale bamboo die off in the 1980s in China. Captive breeding programs have produced a large population in zoos and efforts continue to reintroduce those animals into the wild. However, we lack sufficient knowledge of their physiological ecology to determine requirements for survival now and in the face of climate change. We measured resting and active metabolic rates of giant pandas in order to determine if current bamboo resources were sufficient for adding additional animals to populations in natural reserves. Resting metabolic rates were somewhat below average for a panda sized mammal and active metabolic rates were in the normal range. Pandas do not have exceptionally low metabolic rates. Nevertheless, there is enough bamboo in natural reserves to support both natural populations and large numbers of reintroduced pandas. Bamboo will not be the limiting factor in successful reintroduction.

  6. Is metabolic rate a universal 'pacemaker' for biological processes?

    PubMed

    Glazier, Douglas S

    2015-05-01

    A common, long-held belief is that metabolic rate drives the rates of various biological, ecological and evolutionary processes. Although this metabolic pacemaker view (as assumed by the recent, influential 'metabolic theory of ecology') may be true in at least some situations (e.g. those involving moderate temperature effects or physiological processes closely linked to metabolism, such as heartbeat and breathing rate), it suffers from several major limitations, including: (i) it is supported chiefly by indirect, correlational evidence (e.g. similarities between the body-size and temperature scaling of metabolic rate and that of other biological processes, which are not always observed) - direct, mechanistic or experimental support is scarce and much needed; (ii) it is contradicted by abundant evidence showing that various intrinsic and extrinsic factors (e.g. hormonal action and temperature changes) can dissociate the rates of metabolism, growth, development and other biological processes; (iii) there are many examples where metabolic rate appears to respond to, rather than drive the rates of various other biological processes (e.g. ontogenetic growth, food intake and locomotor activity); (iv) there are additional examples where metabolic rate appears to be unrelated to the rate of a biological process (e.g. ageing, circadian rhythms, and molecular evolution); and (v) the theoretical foundation for the metabolic pacemaker view focuses only on the energetic control of biological processes, while ignoring the importance of informational control, as mediated by various genetic, cellular, and neuroendocrine regulatory systems. I argue that a comprehensive understanding of the pace of life must include how biological activities depend on both energy and information and their environmentally sensitive interaction. This conclusion is supported by extensive evidence showing that hormones and other regulatory factors and signalling systems coordinate the processes of

  7. Effect of thiamine pyrophosphate on levels of serum lactate, maximum oxygen consumption and heart rate in athletes performing aerobic activity.

    PubMed

    Bautista-Hernández, V M; López-Ascencio, R; Del Toro-Equihua, M; Vásquez, C

    2008-01-01

    The aim of this study was to determine the effect of thiamine pyrophosphate (TPP) on serum lactate levels, maximum oxygen consumption (Vo(2max)) and heart rate in male athletes performing aerobic activity. A double-blind, randomized, crossover study was performed in which lactate levels, Vo(2max) and heart rates in 27 male athletes were compared at rest and after exercise, following administration of placebo (sodium chloride 0.9%) or TPP (1 mg/kg). At rest, serum lactate levels after placebo or TPP were similar; however, after exercise, the levels were lower in the athletes after taking TPP than after placebo. During exercise, Vo(2max) in athletes on TPP was higher than on placebo. At rest, heart rate after taking placebo or TPP was similar but, after exercise, heart rate was lower after taking TPP than after placebo. It is concluded that TPP caused serum lactate levels and heart rate to be lower than placebo and Vo(2max) to be higher in athletes performing aerobic physical activity.

  8. 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

  9. Effects of 12 weeks combined aerobic and resistance exercise on heart rate variability in type 2 diabetes mellitus patients

    PubMed Central

    Kang, Seol-Jung; Ko, Kwang-Jun; Baek, Un-Hyo

    2016-01-01

    [Purpose] This study evaluated the effects of 12 weeks combined aerobic and resistance exercise on heart rate variability in patients with Type 2 diabetes mellitus. [Subjects and Methods] The subjects were 16 female patients with Type 2 diabetes mellitus selected among the participants of a chronic disease management exercise class at C Region Public Health Center in South Korea. Subjects were randomly assigned to the exercise group (n=8; age, 55.97 ± 7.37) or the control group (n=8; age, 57.53 ± 4.63) The exercise group performed aerobic and resistance exercises for 60 minutes per day, 3 times per week for 12 weeks. Anthropometric measurements, biochemical markers, physical fitness, and heart rate variability were examined. [Results] After 12 weeks of exercise, weight, body fat percentage, waist circumference, blood glucose, insulin resistance, glycated hemoglobin level, systolic blood pressure, and diastolic blood pressure significantly decreased and cardiorespiratory fitness and muscular strength significantly increased in the exercise group. Although heart rate variability measures showed favorable changes with the exercise program, none were significant. [Conclusion] Although the exercise program did not show notable changes in heart rate variability in patients with Type 2 diabetes within the timeframe of the study, exercise may contribute to the prevention and control of cardiovascular autonomic neuropathy. PMID:27512271

  10. Effects of 12 weeks combined aerobic and resistance exercise on heart rate variability in type 2 diabetes mellitus patients.

    PubMed

    Kang, Seol-Jung; Ko, Kwang-Jun; Baek, Un-Hyo

    2016-07-01

    [Purpose] This study evaluated the effects of 12 weeks combined aerobic and resistance exercise on heart rate variability in patients with Type 2 diabetes mellitus. [Subjects and Methods] The subjects were 16 female patients with Type 2 diabetes mellitus selected among the participants of a chronic disease management exercise class at C Region Public Health Center in South Korea. Subjects were randomly assigned to the exercise group (n=8; age, 55.97 ± 7.37) or the control group (n=8; age, 57.53 ± 4.63) The exercise group performed aerobic and resistance exercises for 60 minutes per day, 3 times per week for 12 weeks. Anthropometric measurements, biochemical markers, physical fitness, and heart rate variability were examined. [Results] After 12 weeks of exercise, weight, body fat percentage, waist circumference, blood glucose, insulin resistance, glycated hemoglobin level, systolic blood pressure, and diastolic blood pressure significantly decreased and cardiorespiratory fitness and muscular strength significantly increased in the exercise group. Although heart rate variability measures showed favorable changes with the exercise program, none were significant. [Conclusion] Although the exercise program did not show notable changes in heart rate variability in patients with Type 2 diabetes within the timeframe of the study, exercise may contribute to the prevention and control of cardiovascular autonomic neuropathy.

  11. Initial reductive reactions in aerobic microbial metabolism of 2,4,6-trinitrotoluene.

    PubMed

    Vorbeck, C; Lenke, H; Fischer, P; Spain, J C; Knackmuss, H J

    1998-01-01

    Because of its high electron deficiency, initial microbial transformations of 2,4,6-trinitrotoluene (TNT) are characterized by reductive rather than oxidation reactions. The reduction of the nitro groups seems to be the dominating mechanism, whereas hydrogenation of the aromatic ring, as described for picric acid, appears to be of minor importance. Thus, two bacterial strains enriched with TNT as a sole source of nitrogen under aerobic conditions, a gram-negative strain called TNT-8 and a gram-positive strain called TNT-32, carried out nitro-group reduction. In contrast, both a picric acid-utilizing Rhodococcus erythropolis strain, HL PM-1, and a 4-nitrotoluene-utilizing Mycobacterium sp. strain, HL 4-NT-1, possessed reductive enzyme systems, which catalyze ring hydrogenation, i.e., the addition of a hydride ion to the aromatic ring of TNT. The hydride-Meisenheimer complex thus formed (H-TNT) was further converted to a yellow metabolite, which by electrospray mass and nuclear magnetic resonance spectral analyses was established as the protonated dihydride-Meisenheimer complex of TNT (2H-TNT). Formation of hydride complexes could not be identified with the TNT-enriched strains TNT-8 and TNT-32, or with Pseudomonas sp. clone A (2NT), for which such a mechanism has been proposed. Correspondingly, reductive denitration of TNT did not occur.

  12. Initial Reductive Reactions in Aerobic Microbial Metabolism of 2,4,6-Trinitrotoluene

    PubMed Central

    Vorbeck, Claudia; Lenke, Hiltrud; Fischer, Peter; Spain, Jim C.; Knackmuss, Hans-Joachim

    1998-01-01

    Because of its high electron deficiency, initial microbial transformations of 2,4,6-trinitrotoluene (TNT) are characterized by reductive rather than oxidation reactions. The reduction of the nitro groups seems to be the dominating mechanism, whereas hydrogenation of the aromatic ring, as described for picric acid, appears to be of minor importance. Thus, two bacterial strains enriched with TNT as a sole source of nitrogen under aerobic conditions, a gram-negative strain called TNT-8 and a gram-positive strain called TNT-32, carried out nitro-group reduction. In contrast, both a picric acid-utilizing Rhodococcus erythropolis strain, HL PM-1, and a 4-nitrotoluene-utilizing Mycobacterium sp. strain, HL 4-NT-1, possessed reductive enzyme systems, which catalyze ring hydrogenation, i.e., the addition of a hydride ion to the aromatic ring of TNT. The hydride-Meisenheimer complex thus formed (H−-TNT) was further converted to a yellow metabolite, which by electrospray mass and nuclear magnetic resonance spectral analyses was established as the protonated dihydride-Meisenheimer complex of TNT (2H−-TNT). Formation of hydride complexes could not be identified with the TNT-enriched strains TNT-8 and TNT-32, or with Pseudomonas sp. clone A (2NT−), for which such a mechanism has been proposed. Correspondingly, reductive denitration of TNT did not occur. PMID:16349484

  13. Pressure and temperature interactions on aerobic metabolism of migrating European silver eel.

    PubMed

    Scaion, D; Belhomme, M; Sébert, P

    2008-12-31

    During their migration for reproduction, European eels have to cope with many environmental factors changes. The main changes concern hydrostatic pressure and temperature that are important environmental and physiological factors when considering life in the deep sea. We focus on the consequences of pressure (from 0.1 to 12.1MPa by 1MPa steps) and temperature (9, 15, 22 degrees C) shifts on the oxygen consumption (MO(2)) at the whole animal level. Because of their morphological differences, we are also interested in males and females to evaluate the best conditions for migration. Firstly, whatever temperature, males present higher aerobic capacities than females at atmospheric pressure. Secondly, an increase in temperature increases the pressure effects in males (synergy) but decreases them in females (opposite effects). We raise the hypothesis that two different migration strategies could be used in the water column in order to reach the breeding area: males could tend to privilege pressure and cold waters (deep water) and females, on the other hand, could opt for warmer temperature surface waters.

  14. Dinosaur Metabolism and the Allometry of Maximum Growth Rate

    PubMed Central

    Myhrvold, Nathan P.

    2016-01-01

    The allometry of maximum somatic growth rate has been used in prior studies to classify the metabolic state of both extant vertebrates and dinosaurs. The most recent such studies are reviewed, and their data is reanalyzed. The results of allometric regressions on growth rate are shown to depend on the choice of independent variable; the typical choice used in prior studies introduces a geometric shear transformation that exaggerates the statistical power of the regressions. The maximum growth rates of extant groups are found to have a great deal of overlap, including between groups with endothermic and ectothermic metabolism. Dinosaur growth rates show similar overlap, matching the rates found for mammals, reptiles and fish. The allometric scaling of growth rate with mass is found to have curvature (on a log-log scale) for many groups, contradicting the prevailing view that growth rate allometry follows a simple power law. Reanalysis shows that no correlation between growth rate and basal metabolic rate (BMR) has been demonstrated. These findings drive a conclusion that growth rate allometry studies to date cannot be used to determine dinosaur metabolism as has been previously argued. PMID:27828977

  15. 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 NH4(+)/LIC, 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 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.

  16. The action of nitrophenols on the metabolic rate of rats

    PubMed Central

    Cameron, Margaret A. M.

    1958-01-01

    The effect of the mono- and di-nitrophenols and certain related compounds has been determined on the rate of oxygen consumption, the rate of carbon dioxide output and the rectal temperature of the Wistar albino rat. Of the compounds examined, only 2:4-dinitrophenol and its derivative, 3:5-dinitro-o-cresol, stimulated metabolic rate. 2-Nitrophenol and 2:3-, 2:6-, and 3:5-dinitrophenol produced no change in metabolic rate; 3-nitrophenol and 2:5-dinitrophenol had no action on carbon dioxide production although they caused a decrease in oxygen consumption. 4-Nitrophenol and 3:4-dinitrophenol increased only the rate of carbon dioxide output; 2-amino-4-nitrophenol increased the rate of carbon dioxide output and decreased the rate of oxygen consumption; 4-amino-2-nitrophenol caused depression of metabolic rate. It was confirmed that neither rectal temperature nor carbon dioxide output could replace rate of oxygen consumption as a reliable index of metabolic stimulant action. An apparatus is described which facilitates measurement of the oxygen consumption of small mammals. PMID:13523130

  17. Resting metabolic rate varies by race and by sleep duration

    PubMed Central

    Spaeth, Andrea M; Dinges, David F; Goel, Namni

    2015-01-01

    Objective Short sleep duration is a significant risk factor for weight gain, particularly in African Americans and men. Increased caloric intake underlies this relationship but it remains unclear whether decreased energy expenditure is a contributory factor. The current study assessed the impact of sleep restriction and recovery sleep on energy expenditure in African American and Caucasian men and women. Methods Healthy adults participated in a controlled laboratory study. After two baseline sleep nights, subjects were randomized to an experimental (n=36; 4h sleep/night for 5 nights followed by 1 night 12h recovery sleep) or control condition (n=11; 10h sleep/night). Resting metabolic rate and respiratory quotient were measured using indirect calorimetry in the morning after overnight fasting. Results Resting metabolic rate—the largest component of energy expenditure—decreased after sleep restriction (−2.6%, p=0.032) and returned to baseline levels after recovery sleep. No changes in resting metabolic rate were observed in control subjects. Relative to Caucasians (n=14), African Americans (n=22) exhibited comparable daily caloric intake but a lower resting metabolic rate (p=0.043) and higher respiratory quotient (p=0.013) regardless of sleep duration. Conclusions Sleep restriction decreased morning resting metabolic rate in healthy adults, suggesting that sleep loss leads to metabolic changes aimed at conserving energy. PMID:26538305

  18. Routine Metabolic Rate of Channel Catfish Ictalurus punctatus Fry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Channel catfish eggs are typically incubated at high density and are often subjected to sub-optimum dissolved oxygen (DO) concentrations while in the hatchery. Since DO plays an important role in the development, hatch rate, and growth of catfish eggs and fry, we measured routine metabolic rate of ...

  19. Elevated plasma corticosterone increases metabolic rate in a terrestrial salamander.

    PubMed

    Wack, Corina L; DuRant, Sarah E; Hopkins, William A; Lovern, Matthew B; Feldhoff, Richard C; Woodley, Sarah K

    2012-02-01

    Plasma glucocorticoid hormones (GCs) increase intermediary metabolism, which may be reflected in whole-animal metabolic rate. Studies in fish, birds, and reptiles have shown that GCs may alter whole-animal energy expenditure, but results are conflicting and often involve GC levels that are not physiologically relevant. A previous study in red-legged salamanders found that male courtship pheromone increased plasma corticosterone (CORT; the primary GC in amphibians) concentrations in males, which could elevate metabolic processes to sustain courtship behaviors. To understand the possible metabolic effect of elevated plasma CORT, we measured the effects of male courtship pheromone and exogenous application of CORT on oxygen consumption in male red-legged salamanders (Plethodon shermani). Exogenous application of CORT elevated plasma CORT to physiologically relevant levels. Compared to treatment with male courtship pheromone and vehicle, treatment with CORT increased oxygen consumption rates for several hours after treatment, resulting in 12% more oxygen consumed (equivalent to 0.33 J) during our first 2h sampling period. Contrary to our previous work, treatment with pheromone did not increase plasma CORT, perhaps because subjects used in this study were not in breeding condition. Pheromone application did not affect respiration rates. Our study is one of the few to evaluate the influence of physiologically relevant elevations in CORT on whole-animal metabolism in vertebrates, and the first to show that elevated plasma CORT increases metabolism in an amphibian.

  20. Fasting Leptin Is a Metabolic Determinant of Food Reward in Overweight and Obese Individuals during Chronic Aerobic Exercise Training

    PubMed Central

    Gibbons, Catherine; Caudwell, Phillipa; Webb, Dominic-Luc; Hellström, Per M.; Näslund, Erik; Blundell, John E.

    2014-01-01

    Changes in food reward have been implicated in exercise-induced compensatory eating behaviour. However, the underlying mechanisms of food reward, and the physiological correlates of exercise-induced changes in food reward, are unknown. Methods. Forty-six overweight and obese individuals completed 12 weeks of aerobic exercise. Body composition, food intake, and fasting metabolic-related hormones were measured at baseline, week six, and postintervention. On separate days, the reward value of high-and-low-fat food (explicit liking and implicit wanting) was also assessed at baseline, week six, and postintervention. Results. Following the intervention, FM, FFM, and VO2peak improved significantly, while fasting leptin decreased. However, food intake or reward did not change significantly. Cross-sectional analyses indicated that FM (P = 0.022) and FFM (P = 0.046) were associated with explicit liking for high-fat food, but implicit wanting was associated with FM only (P = 0.005). Fasting leptin was associated with liking (P = 0.023) and wanting (P = 0.021) for high-fat food. Furthermore, a greater exercise-induced decline in fasting leptin was associated with increased liking (P = 0.018). Conclusion. These data indicate that food reward has a number of physiological correlates. In particular, fasting leptin appears to play an active role in mediating food reward during exercise-induced weight loss. PMID:24734042

  1. Honeybee flight metabolic rate: does it depend upon air temperature?

    PubMed

    Woods, William A; Heinrich, Bernd; Stevenson, Robert D

    2005-03-01

    Differing conclusions have been reached as to how or whether varying heat production has a thermoregulatory function in flying honeybees Apis mellifera. We investigated the effects of air temperature on flight metabolic rate, water loss, wingbeat frequency, body segment temperatures and behavior of honeybees flying in transparent containment outdoors. For periods of voluntary, uninterrupted, self-sustaining flight, metabolic rate was independent of air temperature between 19 and 37 degrees C. Thorax temperatures (T(th)) were very stable, with a slope of thorax temperature on air temperature of 0.18. Evaporative heat loss increased from 51 mW g(-1) at 25 degrees C to 158 mW g(-1) at 37 degrees C and appeared to account for head and abdomen temperature excess falling sharply over the same air temperature range. As air temperature increased from 19 to 37 degrees C, wingbeat frequency showed a slight but significant increase, and metabolic expenditure per wingbeat showed a corresponding slight but significant decrease. Bees spent an average of 52% of the measurement period in flight, with 19 of 78 bees sustaining uninterrupted voluntary flight for periods of >1 min. The fraction of time spent flying declined as air temperature increased. As the fraction of time spent flying decreased, the slope of metabolic rate on air temperature became more steeply negative, and was significant for bees flying less than 80% of the time. In a separate experiment, there was a significant inverse relationship of metabolic rate and air temperature for bees requiring frequent or constant agitation to remain airborne, but no dependence for bees that flew with little or no agitation; bees were less likely to require agitation during outdoor than indoor measurements. A recent hypothesis explaining differences between studies in the slope of flight metabolic rate on air temperature in terms of differences in metabolic capacity and thorax temperature is supported for honeybees in voluntary

  2. Antidepressants Alter Cerebrovascular Permeability and Metabolic Rate in Primates

    NASA Astrophysics Data System (ADS)

    Preskorn, Sheldon H.; Raichle, Marcus E.; Hartman, Boyd K.

    1982-07-01

    External detection of the annihilation radiation produced by water labeled with oxygen-15 was used to measure cerebrovascular permeability and cerebral blood flow in six rhesus monkeys. Use of oxygen-15 also permitted assessment of cerebral metabolic rate in two of the monkeys. Amitriptyline produced a dose-dependent, reversible increase in permeability at plasma drug concentrations which are therapeutic for depressed patients. At the same concentrations the drug also produced a 20 to 30 percent reduction in cerebral metabolic rate. At higher doses normal autoregulation of cerebral blood flow was suspended, but responsivity to arterial carbon dioxide was normal.

  3. Comparison of metabolic expenditure during CAEP versus a test adapted to aerobic capacity (Harbor test) in elderly healthy individuals.

    PubMed

    Page, E; Bonnet, J L; Durand, C

    2000-11-01

    Cardiopulmonary exercise tests are frequently used to test rate responsive pacemakers. The chronotropic assessment exercise protocol (CAEP) has been specifically proposed for the evaluation of rate responsive pacing systems. A mathematical method, based on CAEP measurements, was developed with a view of normalizing the exercise induced metabolic response. CAEP was compared to a tailored protocol (Harbor), adapted to the metabolic capacity of each patient. Harbor was set to keep the exercise duration within 10 minutes and achieve a workload as linear as possible. Metabolic parameters were continuously recorded by a cardiopulmonary system. Those data were used in the construction of slopes by the normalization method. The results of the tests performed in 16 elderly healthy patients showed no differences in metabolic or functional parameters. Slopes of the mathematical model were comparable (1.09 +/- 0.16 for CAEP vs 1.07 +/- 0.17 for Harbor), though both were higher than the value of 1, defined as normal. In both cases, linearity was confirmed by the coefficient of correlation (0.98 +/- 0.02 for CAEP and Harbor). In conclusion, no significant differences were found in the outcomes of the two protocols. Higher values of the slopes with the normalization method can be explained by the definition of the maximal predicted heart rate as 220--age, which is probably not appropriate for elderly, healthy, active subjects.

  4. 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

    2012-09-30

    Cells from Northern Elephant Seals to Study the Mechanisms that Maintain Aerobic Metabolism Under the Hypoxic Conditions of Breath-hold Diving...To isolate and culture primary muscle cells from the swimming muscles of northern elephant seals . OBJECTIVES Objective 1. To test the...Proof of Concept to Isolate and Culture Primary Muscle Cells from Northern Elephant Seals to Study the Mechanisms that Maintain Aerobic Metabolism Under

  5. Metabolically Derived Human Ventilation Rates: A Revised Approach Based Upon Oxygen Consumption Rates (Final Report, 2009)

    EPA Science Inventory

    EPA announced the availability of the final report, Metabolically Derived Human Ventilation Rates: A Revised Approach Based Upon Oxygen Consumption Rates. This report provides a revised approach for calculating an individual's ventilation rate directly from their oxygen c...

  6. Instantaneous Metabolic Cost of Walking: Joint-Space Dynamic Model with Subject-Specific Heat Rate

    PubMed Central

    Roberts, Dustyn; Hillstrom, Howard; Kim, Joo H.

    2016-01-01

    A subject-specific model of instantaneous cost of transport (ICOT) is introduced from the joint-space formulation of metabolic energy expenditure using the laws of thermodynamics and the principles of multibody system dynamics. Work and heat are formulated in generalized coordinates as functions of joint kinematic and dynamic variables. Generalized heat rates mapped from muscle energetics are estimated from experimental walking metabolic data for the whole body, including upper-body and bilateral data synchronization. Identified subject-specific energetic parameters—mass, height, (estimated) maximum oxygen uptake, and (estimated) maximum joint torques—are incorporated into the heat rate, as opposed to the traditional in vitro and subject-invariant muscle parameters. The total model metabolic energy expenditure values are within 5.7 ± 4.6% error of the measured values with strong (R2 > 0.90) inter- and intra-subject correlations. The model reliably predicts the characteristic convexity and magnitudes (0.326–0.348) of the experimental total COT (0.311–0.358) across different subjects and speeds. The ICOT as a function of time provides insights into gait energetic causes and effects (e.g., normalized comparison and sensitivity with respect to walking speed) and phase-specific COT, which are unavailable from conventional metabolic measurements or muscle models. Using the joint-space variables from commonly measured or simulated data, the models enable real-time and phase-specific evaluations of transient or non-periodic general tasks that use a range of (aerobic) energy pathway similar to that of steady-state walking. PMID:28030598

  7. Metabolite analysis of Mycobacterium species under aerobic and hypoxic conditions reveals common metabolic traits.

    PubMed

    Drapal, Margit; Wheeler, Paul R; Fraser, Paul D

    2016-08-01

    A metabolite profiling approach has been implemented to elucidate metabolic adaptation at set culture conditions in five Mycobacterium species (two fast- and three slow-growing) with the potential to act as model organisms for Mycobacterium tuberculosis (Mtb). Analysis has been performed over designated growth phases and under representative environments (nutrient and oxygen depletion) experienced by Mtb during infection. The procedure was useful in determining a range of metabolites (60-120 compounds) covering nucleotides, amino acids, organic acids, saccharides, fatty acids, glycerols, -esters, -phosphates and isoprenoids. Among these classes of compounds, key biomarker metabolites, which can act as indicators of pathway/process activity, were identified. In numerous cases, common metabolite traits were observed for all five species across the experimental conditions (e.g. uracil indicating DNA repair). Amino acid content, especially glutamic acid, highlighted the different properties between the fast- and slow-growing mycobacteria studied (e.g. nitrogen assimilation). The greatest similarities in metabolite composition between fast- and slow-growing mycobacteria were apparent under hypoxic conditions. A comparison to previously reported transcriptomic data revealed a strong correlation between changes in transcription and metabolite content. Collectively, these data validate the changes in the transcription at the metabolite level, suggesting transcription exists as one of the predominant modes of cellular regulation in Mycobacterium. Sectors with restricted correlation between metabolites and transcription (e.g. hypoxic cultivation) warrant further study to elucidate and exploit post-transcriptional modes of regulation. The strong correlation between the laboratory conditions used and data derived from in vivo conditions, indicate that the approach applied is a valuable addition to our understanding of cell regulation in these Mycobacterium species.

  8. The rate of training response to aerobic exercise affects brain function of rats.

    PubMed

    Marton, Orsolya; Koltai, Erika; Takeda, Masaki; Mimura, Tatsuya; Pajk, Melitta; Abraham, Dora; Koch, Lauren Gerard; Britton, Steven L; Higuchi, Mitsuru; Boldogh, Istvan; Radak, Zsolt

    2016-10-01

    There is an increasing volume of data connecting capacity to respond to exercise training with quality of life and aging. In this study, we used a rat model in which animals were selectively bred for low and high gain in running distance to test t whether genetic segregation for trainability is associated with brain function and signaling processes in the hippocampus. Rats selected for low response (LRT) and high response training (HRT) were randomly divided into control or exercise group that trained five times a week for 30 min per day for three months at 70% VO2max. All four groups had similar running distance before training. With training, HRT rats showed significantly greater increases in VO2max and running distance than LRT rats (p < 0.05). On the reverse Morris Maze test HRT-trained rats outperformed HRT control ones. Significant difference was noted between LRT and HRT groups in redox milieu as assessed by levels of reactive oxygen species (ROS), carbonylation of proteins, nNOS and S-nitroso-cysteine. Moreover the silent information regulator 1 (SIRT1), brain-derived neurotrophic factor (BDNF), ratio of phospho and total cAMP-response element binding protein (CREB), and apoptotic index, also showed significant differences between LRT and HRT groups. These findings suggest that aerobic training responses are not localized to skeletal muscle, but differently involve signaling processes in the brain of LRT and HRT rats.

  9. Dopamine modulates metabolic rate and temperature sensitivity in Drosophila melanogaster.

    PubMed

    Ueno, Taro; Tomita, Jun; Kume, Shoen; Kume, Kazuhiko

    2012-01-01

    Homeothermal animals, such as mammals, maintain their body temperature by heat generation and heat dissipation, while poikilothermal animals, such as insects, accomplish it by relocating to an environment of their favored temperature. Catecholamines are known to regulate thermogenesis and metabolic rate in mammals, but their roles in other animals are poorly understood. The fruit fly, Drosophila melanogaster, has been used as a model system for the genetic studies of temperature preference behavior. Here, we demonstrate that metabolic rate and temperature sensitivity of some temperature sensitive behaviors are regulated by dopamine in Drosophila. Temperature-sensitive molecules like dTrpA1 and shi(ts) induce temperature-dependent behavioral changes, and the temperature at which the changes are induced were lowered in the dopamine transporter-defective mutant, fumin. The mutant also displays a preference for lower temperatures. This thermophobic phenotype was rescued by the genetic recovery of the dopamine transporter in dopamine neurons. Flies fed with a dopamine biosynthesis inhibitor (3-iodo-L-tyrosine), which diminishes dopamine signaling, exhibited preference for a higher temperature. Furthermore, we found that the metabolic rate is up-regulated in the fumin mutant. Taken together, dopamine has functions in the temperature sensitivity of behavioral changes and metabolic rate regulation in Drosophila, as well as its previously reported functions in arousal/sleep regulation.

  10. Cross-validation of resting metabolic rate prediction equations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: Knowledge of the resting metabolic rate (RMR) is necessary for determining individual total energy requirements. Measurement of RMR is time consuming and requires specialized equipment. Prediction equations provide an easy method to estimate RMR; however, the accuracy of these equations...

  11. Relationships Between Metabolic Rate, Muscle Electromyograms and Swim Performance of Adult Chinook Salmon

    SciTech Connect

    Geist, David R.; Brown, Richard S.; Cullinan, Valerie I.; Mesa, Matthew G.; VanderKooi, S P.; McKinstry, Craig A.

    2003-10-01

    In 2000 Pacific Northwest National Laboratory initiated a two-year study to investigate the metabolic rate and swimming performance and to estimate the total energy used (i.e., aerobic and anaerobic) by adult spring Chinook salmon migrating upstream through a large hydropower dam on the Columbia River. The investigation involved one year of laboratory study and one year of field study at Bonneville Dam. The objectives of the laboratory study, reported here, were to (1) measure active rates of oxygen consumption of adult spring chinook salmon at three water temperatures over a range of swimming speeds; (2) estimate the Ucrit of adult spring chinook salmon; and (3) monitor EMGs of red and white muscle in the salmon over a range of swimming speeds. Future papers will report on the results of the field study. Our results indicated that the rate of oxygen consumption and red and white muscle activity in adult spring chinook salmon were strongly correlated with swimming speed over a range of fish sizes and at three different temperatures. Active oxygen consumption increased linearly with swim speed before leveling off at speeds at or above Ucrit. This pattern was similar at each water temperature and indicated that fish were approaching their maximal aerobic oxygen consumption at higher swim speeds. Modeling showed that temperature, but not size or sex, influenced the relation between V02 and swim speed, thus a V02-swim speed model based on temperature (but independent of sex and size) should be a biologically relevant way of estimating the energy use of fish in the wild.

  12. Gait Dynamics and Locomotor Metabolism

    DTIC Science & Technology

    2013-10-01

    weighted and unweighted walking metabolic rates can be estimated in field settings using simple, inexpensive wearable technologies. Metabolic rates...our walking model and to continue to work toward the final algorithm and publication of a walking test for predicting aerobic fitness . The...number of subjects tested in the last year was limited and targeted toward enrolling highly aerobically fit subjects needed for objective two

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

    PubMed Central

    Liao, Yi-Hung; Sung, Yu-Chi

    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

  14. Rates of microbial metabolism in deep coastal plain aquifers.

    PubMed

    Chapelle, F H; Lovley, D R

    1990-06-01

    Rates of microbial metabolism in deep anaerobic aquifers of the Atlantic coastal plain of South Carolina were investigated by both microbiological and geochemical techniques. Rates of [2-C]acetate and [U-C]glucose oxidation as well as geochemical evidence indicated that metabolic rates were faster in the sandy sediments composing the aquifers than in the clayey sediments of the confining layers. In the sandy aquifer sediments, estimates of the rates of CO(2) production (millimoles of CO(2) per liter per year) based on the oxidation of [2-C] acetate were 9.4 x 10 to 2.4 x 10 for the Black Creek aquifer, 1.1 x 10 for the Middendorf aquifer, and <7 x 10 for the Cape Fear aquifer. These estimates were at least 2 orders of magnitude lower than previously published estimates that were based on the accumulation of CO(2) in laboratory incubations of similar deep subsurface sediments. In contrast, geochemical modeling of groundwater chemistry changes along aquifer flowpaths gave rate estimates that ranged from 10 to 10 mmol of CO(2) per liter per year. The age of these sediments (ca. 80 million years) and their organic carbon content suggest that average rates of CO(2) production could have been no more than 10 mmol per liter per year. Thus, laboratory incubations may greatly overestimate the in situ rates of microbial metabolism in deep subsurface environments. This has important implications for the use of laboratory incubations in attempts to estimate biorestoration capacities of deep aquifers. The rate estimates from geochemical modeling indicate that deep aquifers are among the most oligotrophic aquatic environments in which there is ongoing microbial metabolism.

  15. Rates of microbial metabolism in deep coastal plain aquifers

    USGS Publications Warehouse

    Chapelle, F.H.; Lovley, D.R.

    1990-01-01

    Rates of microbial metabolism in deep anaerobic aquifers of the Atlantic coastal plain of South Carolina were investigated by both microbiological and geochemical techniques. Rates of [2-14C]acetate and [U-14C]glucose oxidation as well as geochemical evidence indicated that metabolic rates were faster in the sandy sediments composing the aquifers than in the clayey sediments of the confining layers. In the sandy aquifer sediments, estimates of the rates of CO2 production (millimoles of CO2 per liter per year) based on the oxidation of [2-14C]acetate were 9.4 x 10-3 to 2.4 x 10-1 for the Black Creek aquifer, 1.1 x 10-2 for the Middendorf aquifer, and <7 x 10-5 for the Cape Fear aquifer. These estimates were at least 2 orders of magnitude lower than previously published estimates that were based on the accumulation of CO2 in laboratory incubations of similar deep subsurface sediments. In contrast, geochemical modeling of groundwater chemistry changes along aquifer flowpaths gave rate estimates that ranged from 10-4 to 10-6 mmol of CO2 per liter per year. The age of these sediments (ca. 80 million years) and their organic carbon content suggest that average rates of CO2 production could have been no more than 10-4 mmol per liter per year. Thus, laboratory incubations may greatly overestimate the in situ rates of microbial metabolism in deep subsurface environments. This has important implications for the use of laboratory incubations in attempts to estimate biorestoration capacities of deep aquifers. The rate estimates from geochemical modeling indicate that deep aquifers are among the most oligotrophic aquatic environments in which there is ongoing microbial metabolism.

  16. Effects of temperature, swimming speed and body mass on standard and active metabolic rate in vendace (Coregonus albula).

    PubMed

    Ohlberger, Jan; Staaks, Georg; Hölker, Franz

    2007-11-01

    This study gives an integrated analysis of the effects of temperature, swimming speed and body mass on standard metabolism and aerobic swimming performance in vendace (Coregonus albula (L.)). The metabolic rate was investigated at 4, 8 and 15 degrees C using one flow-through respirometer and two intermittent-flow swim tunnels. We found that the standard metabolic rate (SMR), which increased significantly with temperature, accounted for up to 2/3 of the total swimming costs at optimum speed (U (opt)), although mean U (opt) was high, ranging from 2.0 to 2.8 body lengths per second. Net swimming costs increased with swimming speed, but showed no clear trend with temperature. The influence of body mass on the metabolic rate varied with temperature and activity level resulting in scaling exponents (b) of 0.71-0.94. A multivariate regression analysis was performed to integrate the effects of temperature, speed and mass (AMR = 0.82M (0.93) exp(0.07T) + 0.43M (0.93) U (2.03)). The regression analysis showed that temperature affects standard but not net active metabolic costs in this species. Further, we conclude that a low speed exponent, high optimum speeds and high ratios of standard to activity costs suggest a remarkably efficient swimming performance in vendace.

  17. Incongruent changes in heart rate variability and body weight after discontinuing aerobic exercise in patients with schizophrenia.

    PubMed

    Hsu, Chung-Chih; Liang, Chih-Sung; Tai, Yueh-Ming; Cheng, Shu-Li

    2016-11-01

    A bidirectional connection exists between obesity and altered heart rate variability (HRV). Schizophrenia has been associated with a high risk of obesity and decreased vagal modulation. Few studies have examined the link between obesity and HRV in patients with schizophrenia. The aim of this study was to investigate the effects of aerobic exercise on body weight and HRV, and if so, whether these effects could be sustained after discontinuation of exercise training. A total of 18 overweight patients with schizophrenia completed an 8-week moderate-intensity aerobic exercise program conducted twice weekly for 50min. Body weight and heart rate variability were measured at baseline, week 8, and 4weeks after discontinuation of exercise training. Compared with the control group (15 overweight patients with schizophrenia without exercise training), the exercise group had reduced 2.3kg at week 8. Furthermore, the exercise program increased the low frequency, high frequency, and low frequency plus high frequency of HRV. However, after discontinuation of the exercise program for 4weeks, the changes in body weight and the HRV parameters diverged. All of the HRV parameters returned to their baseline values, but no change was seen in the reduced body weight. This suggests that HRV analysis is a more sensitive tool to detect health conditions in patients with schizophrenia. Although exercise is an easy and effective way to prevent and improve health problems, mental health providers might have underestimated the benefits of exercise in daily clinical practice. A regular exercise program should be considered as an essential part of treatment strategies for patients with schizophrenia.

  18. Enhancing of Women Functional Status with Metabolic Syndrome by Cardioprotective and Anti-Inflammatory Effects of Combined Aerobic and Resistance Training

    PubMed Central

    Alsamir Tibana, Ramires; da Cunha Nascimento, Dahan; Frade de Sousa, Nuno Manuel; de Souza, Vinicius Carolino; Durigan, João; Vieira, Amilton; Bottaro, Martim; de Toledo Nóbrega, Otávio; de Almeida, Jeeser Alves; Navalta, James Wilfred; Franco, Octavio Luiz; Prestes, Jonato

    2014-01-01

    These data describe the effects of combined aerobic plus resistance training (CT) with regards to risk factors of metabolic syndrome (MetS), quality of life, functional capacity, and pro- and anti-inflammatory cytokines in women with MetS. In this context, thirteen women (35.4±6.2 yr) completed 10 weeks of CT consisting of three weekly sessions of ∼60 min aerobic training (treadmill at 65–70% of reserve heart rate, 30 min) and resistance training (3 sets of 8–12 repetitions maximum for main muscle groups). Dependent variables were maximum chest press strength; isometric hand-grip strength; 30 s chair stand test; six minute walk test; body mass; body mass index; body adiposity index; waist circumference; systolic (SBP), diastolic and mean blood pressure (MBP); blood glucose; HDL-C; triglycerides; interleukins (IL) 6, 10 and 12, osteoprotegerin (OPG) and serum nitric oxide metabolite (NOx); quality of life (SF-36) and Z-Score of MetS. There was an improvement in muscle strength on chest press (p = 0.009), isometric hand-grip strength (p = 0.03) and 30 s chair stand (p = 0.007). There was a decrease in SBP (p = 0.049), MBP (p = 0.041), Z-Score of MetS (p = 0.046), OPG (0.42±0.26 to 0.38±0.19 ng/mL, p<0.05) and NOx (13.3±2.3 µmol/L to 9.1±2.3 µmol/L; p<0.0005). IL-10 displayed an increase (13.6±7.5 to 17.2±12.3 pg/mL, p<0.05) after 10 weeks of training. Combined training also increased the perception of physical capacity (p = 0.011). This study endorses CT as an efficient tool to improve blood pressure, functional capacity, quality of life and reduce blood markers of inflammation, which has a clinical relevance in the prevention and treatment of MetS. Trial Registration Brazilian Clinical Trials Registry (ReBec) - RBR-6gdyvz - http://www.ensaiosclinicos.gov.br/rg/?q=RBR-6gdyvz PMID:25379699

  19. Scaling of resting and maximum hopping metabolic rate throughout the life cycle of the locust Locusta migratoria.

    PubMed

    Snelling, Edward P; Seymour, Roger S; Matthews, Philip G D; Runciman, Sue; White, Craig R

    2011-10-01

    The hemimetabolous migratory locust Locusta migratoria progresses through five instars to the adult, increasing in size from 0.02 to 0.95 g, a 45-fold change. Hopping locomotion occurs at all life stages and is supported by aerobic metabolism and provision of oxygen through the tracheal system. This allometric study investigates the effect of body mass (Mb) on oxygen consumption rate (MO2, μmol h(-1)) to establish resting metabolic rate (MRO2), maximum metabolic rate during hopping (MMO2) and maximum metabolic rate of the hopping muscles (MMO2,hop) in first instar, third instar, fifth instar and adult locusts. Oxygen consumption rates increased throughout development according to the allometric equations MRO2=30.1Mb(0.83±0.02), MMO2=155Mb(1.01±0.02), MMO2,hop=120Mb(1.07±0.02) and, if adults are excluded, MMO2,juv=136Mb(0.97±0.02) and MMO2,juv,hop=103Mb(1.02±0.02). Increasing body mass by 20-45% with attached weights did not increase mass-specific MMO2 significantly at any life stage, although mean mass-specific hopping MO2 was slightly higher (ca. 8%) when juvenile data were pooled. The allometric exponents for all measures of metabolic rate are much greater than 0.75, and therefore do not support West, Brown and Enquist’s optimised fractal network model, which predicts that metabolism scales with a 3⁄4-power exponent owing to limitations in the rate at which resources can be transported within the body.

  20. Combining Disparate Measures of Metabolic Rate During Simulated Spacewalks

    NASA Technical Reports Server (NTRS)

    Feiveson, Alan H.; Kuznetz, Larry; Nguyen, Dan

    2009-01-01

    Scientists from NASA's Extravehicular Activities (EVA) Physiology Systems and Performance Project help design space suits for future missions, during which astronauts are expected to perform EVA activities on the Lunar or Martian surface. During an EVA, an astronaut s integrated metabolic rate is used to predict how much longer the activity can continue and still provide a safe margin of remaining consumables. For EVAs in the Apollo era, NASA physicians monitored live data feeds of heart rate, O2 consumption, and liquid cooled garment (LCG) temperatures, which were subjectively combined or compared to produce an estimate of metabolic rate. But these multiple data feeds sometimes provided conflicting estimates of metabolic rate, making real-time calculations of remaining time difficult for physician/monitors. Currently, designs planned for the Constellation Program EVAs utilize an automated, but largely heuristic methodology for incorporating the above three measurements, plus an additional one - CO2 production, ignoring data that appears in conflict; however a more rigorous model-based approach is desirable. In this study, we show how principal axis factor analysis, in combination with OLS regression and LOWESS smoothing can be used to estimate metabolic rate as a data-driven weighted average of heart rate, O2 consumption, LCG temperature data, and CO2 production. Preliminary results suggest less sensitivity to occasional spikes in observed data feeds, and reasonable within-subject reproducibility when applied to subsequent tasks. These methods do not require physician monitoring and as such can be automated in the electronic components of future space suits. With additional validation, our models show promise for increasing astronaut safety, while reducing the need for and potential errors associated with human monitoring of multiple systems.

  1. Permissivity of the biphenyl-specific aerobic bacterial metabolic pathway towards analogues with various steric requirements.

    PubMed

    Overwin, Heike; Standfuß-Gabisch, Christine; González, Myriam; Méndez, Valentina; Seeger, Michael; Reichelt, Joachim; Wray, Victor; Hofer, Bernd

    2015-09-01

    It has repeatedly been shown that aryl-hydroxylating dioxygenases do not possess a very high substrate specificity. To gain more insight into this phenomenon, we examined two powerful biphenyl dioxygenases, the well-known wild-type enzyme from Burkholderia xenovorans LB400 (BphA-LB400) and a hybrid enzyme, based on a dioxygenase from Pseudomonas sp. B4-Magdeburg (BphA-B4h), for their abilities to dioxygenate a selection of eight biphenyl analogues in which the second aromatic ring was replaced by aliphatic as well as aliphatic/aromatic moieties, reflecting a variety of steric requirements. Interestingly, both enzymes were able to catalyse transformation of almost all of these compounds. While the products formed were identical, major differences were observed in transformation rates. In most cases, BphA-B4h proved to be a significantly more powerful catalyst than BphA-LB400. NMR characterization of the reaction products showed that the metabolite obtained from biphenylene underwent angular dioxygenation, whereas all other compounds were subject to lateral dioxygenation at ortho and meta carbons. Subsequent growth studies revealed that both dioxygenase source strains were able to utilize several of the biphenyl analogues as sole sources of carbon and energy. Therefore, prototype BphBCD enzymes of the biphenyl degradative pathway were examined for their ability to further catabolize the lateral dioxygenation products. All of the ortho- and meta-hydroxylated compounds were converted to acids, showing that this pathway is quite permissive, enabling catalysis of the turnover of a fairly wide variety of metabolites.

  2. 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

  3. 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

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

    2013-12-18

    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.

  4. Effects of short-term aerobic exercise with and without external loading on bone metabolism and balance in postmenopausal women with osteoporosis.

    PubMed

    Roghani, Tayebeh; Torkaman, Giti; Movasseghe, Shafieh; Hedayati, Mehdi; Goosheh, Babak; Bayat, Noushin

    2013-02-01

    The aim of this study is to evaluate the effect of submaximal aerobic exercise with and without external loading on bone metabolism and balance in postmenopausal women with osteoporosis (OP). Thirty-six volunteer, sedentary postmenopausal women with OP were randomly divided into three groups: aerobic, weighted vest, and control. Exercise for the aerobic group consisted of 18 sessions of submaximal treadmill walking, 30 min daily, 3 times a week. The exercise program for the weighted-vest group was identical to that of the aerobic group except that the subjects wore a weighted vest (4-8 % of body weight). Body composition, bone biomarkers, bone-specific alkaline phosphatase (BALP) and N-terminal telopeptide of type 1 collagen (NTX), and balance (near tandem stand, NTS, and star-excursion, SE) were measured before and after the 6-week exercise program. Fat decreased (p = 0.01) and fat-free mass increased (p = 0.005) significantly in the weighted-vest group. BALP increased and NTX decreased significantly in both exercise groups (p ≤ 0.05). After 6 weeks of exercise, NTS score increased in the exercise groups and decreased in the control group (aerobic: +49.68 %, weighted vest: +104.66 %, and control: -28.96 %). SE values for all directions increased significantly in the weighted-vest group. Results showed that the two exercise programs stimulate bone synthesis and decrease bone resorption in postmenopausal women with OP, but that exercise while wearing a weighted vest is better for improving balance.

  5. What do metabolic rates tell us about thermal niches? Mechanisms driving crayfish distributions along an altitudinal gradient.

    PubMed

    Stoffels, Rick J; Richardson, Adam J; Vogel, Matthew T; Coates, Simon P; Müller, Warren J

    2016-01-01

    Humans are rapidly altering thermal landscapes, so a central challenge to organismal ecologists is to better understand the thermal niches of ectotherms. However, there is much disagreement over how we should go about this. Some ecologists assume that a statistical model of abundance as a function of habitat temperature provides a sufficient approximation of the thermal niche, but ecophysiologists have shown that the relationship between fitness and temperature can be complicated, and have stressed the need to elucidate the causal mechanisms underlying the response of species to thermal change. Towards this end, we studied the distribution of two crayfishes, Euastacus woiwuru and Euastacus armatus, along an altitudinal gradient, and for both species conducted experiments to determine the temperature-dependence of: (1) aerobic scope (the difference between maximum and basal metabolic rate; purported to be a proxy of the thermal niche); and (2) burst locomotor performance (primarily fuelled using anaerobic pathways). E. woiwuru occupied cooler habitats than E. armatus, but we found no difference in aerobic scope between these species. In contrast, locomotor performance curves differed significantly and strongly between species, with peak locomotor performances of E. woiwuru and E. armatus occurring at ~10 and ~18 °C, respectively. Crayfish from different thermal landscapes may have similar aerobic thermal performance curves but different anaerobic thermal performance curves. Our results support a growing body of literature implying different components of ectotherm fitness have different thermal performance curves, and further challenge our understanding of the ecology and evolution of thermal niches.

  6. Methods matter: considering locomotory mode and respirometry technique when estimating metabolic rates of fishes

    PubMed Central

    Rummer, Jodie L.; Binning, Sandra A.; Roche, Dominique G.; Johansen, Jacob L.

    2016-01-01

    Respirometry is frequently used to estimate metabolic rates and examine organismal responses to environmental change. Although a range of methodologies exists, it remains unclear whether differences in chamber design and exercise (type and duration) produce comparable results within individuals and whether the most appropriate method differs across taxa. We used a repeated-measures design to compare estimates of maximal and standard metabolic rates (MMR and SMR) in four coral reef fish species using the following three methods: (i) prolonged swimming in a traditional swimming respirometer; (ii) short-duration exhaustive chase with air exposure followed by resting respirometry; and (iii) short-duration exhaustive swimming in a circular chamber. We chose species that are steady/prolonged swimmers, using either a body–caudal fin or a median–paired fin swimming mode during routine swimming. Individual MMR estimates differed significantly depending on the method used. Swimming respirometry consistently provided the best (i.e. highest) estimate of MMR in all four species irrespective of swimming mode. Both short-duration protocols (exhaustive chase and swimming in a circular chamber) produced similar MMR estimates, which were up to 38% lower than those obtained during prolonged swimming. Furthermore, underestimates were not consistent across swimming modes or species, indicating that a general correction factor cannot be used. However, SMR estimates (upon recovery from both of the exhausting swimming methods) were consistent across both short-duration methods. Given the increasing use of metabolic data to assess organismal responses to environmental stressors, we recommend carefully considering respirometry protocols before experimentation. Specifically, results should not readily be compared across methods; discrepancies could result in misinterpretation of MMR and aerobic scope. PMID:27382471

  7. [Specific growth rate and the rate of energy metabolism in the ontogenesis of axolotl, Ambystoma mexicanum (Amphibia: Ambystomatidae)].

    PubMed

    Vladimirova, I G; Kleĭmenov, S Iu; Alekseeva, T A; Radzinskaia, L I

    2003-01-01

    Concordant changes in the rate of energy metabolism and specific growth rate of axolotls have been revealed. Several periods of ontogeny are distinguished, which differ in the ratio of energy metabolism to body weight and, therefore, are described by different allometric equations. It is suggested that the specific growth rate of an animal determines the type of dependence of energy metabolism on body weight.

  8. A comparison of COSMED metabolic systems for the determination of resting metabolic rate.

    PubMed

    Vandarakis, Dimitria; Salacinski, Amanda J; Broeder, Craig E

    2013-01-01

    This study determined the reliability of measuring resting metabolic rate (RMR) with COSMED's FitMate™ metabolic system using a canopy dilution set-up compared with a previously validated COSMED QUARK CPET research-based system in 30 healthy adults (age: 28.4 ± 7.0 yrs, weight: 79.9 ± 20.2 kg, percent body fat: 22.5 ± 8.6%). The FitMate was developed as an inexpensive metabolic system for RMR and fitness testing. Subjects were randomly assigned to start testing on either the FitMate or Quark CPET for four 10-minute measurements. Test-retest intraclass correlations were 0.95-0.99, p ≤ 0.0001 for all parameters tested. Ve, RMR, VO2, and heart rate were not significantly different between the two systems. These results suggest that the FitMate is a reliable canopy dilution system for RMR measurements in healthy adults.

  9. Relationship among body mass, metabolic rate and the intrinsic rate of natural increase in mammals.

    PubMed

    Hennemann, Willard W

    1983-01-01

    The intrinsic rate of natural increase, rm, was calculated for 44 mammalian species using the Cole (1954) equation and life history data from the literature. Values of r m so calculated were plotted as log10 r m versus log10 body mass revealing a linear relationship with a slope of-0.2622. The equation of the regression line fitting these data was then used to correct r m for body mass so that interspecific comparisons with respect to r m and basal metabolic rate could be made to determine if a positive relationship exists between these two parameters. Basal metabolic rate correlates positively with r m, and apparently is one of many factors operating in the evolution of r m. Implications of these conclusions with respect to food habits, resource limitations, and the possible existence of a trade-off between maintenance and reproduction in certain environments is discussed.If one assumes that all mammals face environmental limits on the amount of energy available for maintenance, growth, and reproduction, it follows that any reduction in maintenance costs should provide more energy for growth and/or reproduction. The proposed existence of such a trade-off between maintenance and reproduction was a major premise upon which MacArthur and Wilson (1967) based their concept of "r- and K-selection". Recently, however, McNab (1980) has suggested that for mammals that reproduce when food is not limiting, an increase in one maintenace cost, i.e. basal metabolic rate, may not detract from but may actually increase the intrinsic rate of natural increase, r m. Although this idea may seem counterintuitive, if one assumes an unlimited amount of energy, the factor limiting growth and reproduction will be the rate at which the energy can be used; a higher metabolic rate will mean a higher rate of biosynthesis, a faster growth rate, s shorter generation time, and hence a higher r m. Since some animal species appear not to be food-limited during their reproductive seasons (Armitage

  10. Heterogeneity of cells may explain allometric scaling of metabolic rate.

    PubMed

    Takemoto, Kazuhiro

    2015-04-01

    The origin of allometric scaling of metabolic rate is a long-standing question in biology. Several models have been proposed for explaining the origin; however, they have advantages and disadvantages. In particular, previous models only demonstrate either two important observations for the allometric scaling: the variability of scaling exponents and predominance of 3/4-power law. Thus, these models have a dispute over their validity. In this study, we propose a simple geometry model, and show that a hypothesis that total surface area of cells determines metabolic rate can reproduce these two observations by combining two concepts: the impact of cell sizes on metabolic rate and fractal-like (hierarchical) organization. The proposed model both theoretically and numerically demonstrates the approximately 3/4-power law although several different biological strategies are considered. The model validity is confirmed using empirical data. Furthermore, the model suggests the importance of heterogeneity of cell size for the emergence of the allometric scaling. The proposed model provides intuitive and unique insights into the origin of allometric scaling laws in biology, despite several limitations of the model.

  11. Comparison of growth rates of aerobic anoxygenic phototrophic bacteria and other bacterioplankton groups in coastal Mediterranean waters.

    PubMed

    Ferrera, Isabel; Gasol, Josep M; Sebastián, Marta; Hojerová, Eva; Koblízek, Michal

    2011-11-01

    Growth is one of the basic attributes of any living organism. Surprisingly, the growth rates of marine bacterioplankton are only poorly known. Current data suggest that marine bacteria grow relatively slowly, having generation times of several days. However, some bacterial groups, such as the aerobic anoxygenic phototrophic (AAP) bacteria, have been shown to grow much faster. Two manipulation experiments, in which grazing, viruses, and resource competition were reduced, were conducted in the coastal Mediterranean Sea (Blanes Bay Microbial Observatory). The growth rates of AAP bacteria and of several important phylogenetic groups (the Bacteroidetes, the alphaproteobacterial groups Roseobacter and SAR11, and the Gammaproteobacteria group and its subgroups the Alteromonadaceae and the NOR5/OM60 clade) were calculated from changes in cell numbers in the manipulation treatments. In addition, we examined the role that top-down (mortality due to grazers and viruses) and bottom-up (resource availability) factors play in determining the growth rates of these groups. Manipulations resulted in an increase of the growth rates of all groups studied, but its extent differed largely among the individual treatments and among the different groups. Interestingly, higher growth rates were found for the AAP bacteria (up to 3.71 day⁻¹) and for the Alteromonadaceae (up to 5.44 day⁻¹), in spite of the fact that these bacterial groups represented only a very low percentage of the total prokaryotic community. In contrast, the SAR11 clade, which was the most abundant group, was the slower grower in all treatments. Our results show that, in general, the least abundant groups exhibited the highest rates, whereas the most abundant groups were those growing more slowly, indicating that some minor groups, such the AAP bacteria, very likely contribute much more to the recycling of organic matter in the ocean than what their abundances alone would predict.

  12. Proteomic analysis reveals perturbed energy metabolism and elevated oxidative stress in hearts of rats with inborn low aerobic capacity

    PubMed Central

    Burniston, Jatin G.; Kenyani, Jenna; Wastling, Jonathan M.; Burant, Charles F.; Qi, Nathan R.; Koch, Lauren G.; Britton, Steven L.

    2012-01-01

    Selection on running capacity has created rat phenotypes of high capacity runners (HCR) that have enhanced cardiac function and low capacity runners (LCR) that exhibit risk factors of metabolic syndrome. We analysed hearts of HCR and LCR from generation 22 of selection using DIGE and identified proteins from MS database searches. The running capacity of HCR was 6-fold greater than LCR. DIGE resolved 957 spots and proteins were unambiguously identified in 369 spots. Protein expression profiling detected 67 statistically significant (P<0.05; false discovery rate <10 %, calculated using q-values) differences between HCR and LCR. Hearts of HCR rats exhibited robust increases in the abundance of each enzyme of the beta-oxidation pathway. In contrast, LCR hearts were characterised by the modulation of enzymes associated with ketone body or amino acid metabolism. LCR also exhibited enhanced expression of antioxidant enzymes such as catalase and greater phosphorylation of alpha B-crystallin at serine 59, which is a common point of convergence in cardiac stress signalling. Thus proteomic analysis revealed selection on low running capacity is associated with perturbations in cardiac energy metabolism and provided the first evidence that the LCR cardiac proteome is exposed to greater oxidative stress. PMID:21751351

  13. Metabolic rate suppression as a mechanism for surviving environmental challenge in fish.

    PubMed

    Richards, Jeffrey G

    2010-01-01

    The ability to reduce metabolic rate during exposure to environmental stress, termed metabolic rate suppression, is thought to be an important component to enhance survival in many organisms. Metabolic rate suppression can be achieved through modifications to behavior, physiology, and cellular biochemistry, all of which act to reduce whole organisms energy expenditure. This chapter will critically evaluate the use of metabolic rate suppression as a response to environmental challenge in fish using three metabolic states: aestivation, hypoxia/anoxia exposure, and diapause.

  14. Metabolic rate: its circadian rhythmicity in the female domestic fowl.

    PubMed Central

    Berman, A; Meltzer, A

    1978-01-01

    1. In quasi-natural cyclic lighting, a circadian rhythm was observed in seven fowls; the range of oscillation of the rhythm was 50% of the mean metabolic level. Little variation was present between the individuals. 2. In fowls maintained for 15 days in isolation under 700 lx (ten fowls) or 0.07 lx (four fowls) constant lighting and at constant temperature free-running rhythms were evident; the range of oscillation was about 12% of the mean level. Large variation prevailed between the individuals in the range of oscillation and in the portion of variance accounted for by periodic regression. In dim light, rhythmicity declined to become non-significant by 8 days of exposure. 3. In four fowls maintained in a 6L/6D regimen for 12 days, metabolic rate was entrained to an ahemeral rhythm; there was no evidence of circadian influence on the metabolic response to light. Little variation was present between the individuals. Rhythmicity was maintained over the experimental period. 4. Metabolic levels were similar on 0.07 lx, 700 lx constant light, during the dark phase of the 6L/6D regimen and during night time in the quasi-natural cyclic lighting. They were also similar on the light phase of the 6L/6D regimen and the quasi-natural lighting. PMID:722545

  15. Uncinate process length in birds scales with resting metabolic rate.

    PubMed

    Tickle, Peter; Nudds, Robert; Codd, Jonathan

    2009-05-27

    A fundamental function of the respiratory system is the supply of oxygen to meet metabolic demand. Morphological constraints on the supply of oxygen, such as the structure of the lung, have previously been studied in birds. Recent research has shown that uncinate processes (UP) are important respiratory structures in birds, facilitating inspiratory and expiratory movements of the ribs and sternum. Uncinate process length (UPL) is important for determining the mechanical advantage for these respiratory movements. Here we report on the relationship between UPL, body size, metabolic demand and locomotor specialisation in birds. UPL was found to scale isometrically with body mass. Process length is greatest in specialist diving birds, shortest in walking birds and intermediate length in all others relative to body size. Examination of the interaction between the length of the UP and metabolic demand indicated that, relative to body size, species with high metabolic rates have corresponding elongated UP. We propose that elongated UP confer an advantage on the supply of oxygen, perhaps by improving the mechanical advantage and reducing the energetic cost of movements of the ribs and sternum.

  16. The effect of crank rate strategy on peak aerobic power and peak physiological responses during arm crank ergometry.

    PubMed

    Smith, Paul M; Doherty, Mike; Price, Michael J

    2007-04-01

    The main aim of this study was to determine whether the use of an imposed or freely chosen crank rate would influence submaximal and peak physiological responses during arm crank ergometry. Fifteen physically active men participated in the study. Their mean age, height, and body mass were 25.9 (s = 6.2) years, 1.80 (s = 0.10) m, and 78.4 (s = 6.1) kg, respectively. The participants performed two incremental peak oxygen consumption (VO(2peak)) tests using an electronically braked ergometer. One test was performed using an imposed crank rate of 80 rev x min(-1), whereas in the other the participants used spontaneously chosen crank rates. The order in which the tests were performed was randomized, and they were separated by at least 2 days. Respiratory data were collected using an on-line gas analysis system, and fingertip capillary blood samples ( approximately 20 microl) were collected for the determination of blood lactate concentration. Heart rate was also recorded throughout the tests. Time to exhaustion was measured and peak aerobic power calculated. Submaximal data were analysed using separate two-way repeated-measures analyses of variance, while differences in peak values were analysed using separate paired t-tests. Variations in spontaneously chosen crank rate were assessed using a one-way analysis of variance with repeated measures. Agreement between the crank rate strategies for the assessment of peak values was examined by calculating intra-class correlation coefficients (ICC) and 95% limits of agreement (95% LoA). While considerable between-participant variations in spontaneously chosen crank rate were observed, the mean value was not different (P > 0.05) from the imposed crank rate of 80 rev x min(-1) at any point. No differences (P > 0.05) were observed for submaximal data between crank strategies. Furthermore, mean peak minute power [158 (s = 20) vs. 158 (s = 18) W], time to exhaustion [739 (s = 118) vs. 727 (s = 111) s], and VO(2peak)[3.09 (s = 0

  17. Modeling Neisseria meningitidis B metabolism at different specific growth rates.

    PubMed

    Baart, Gino J E; Willemsen, Marieke; Khatami, Elnaz; de Haan, Alex; Zomer, Bert; Beuvery, E Coen; Tramper, Johannes; Martens, Dirk E

    2008-12-01

    Neisseria meningitidis is a human pathogen that can infect diverse sites within the human host. The major diseases caused by N. meningitidis are responsible for death and disability, especially in young infants. At the Netherlands Vaccine Institute (NVI) a vaccine against serogroup B organisms is currently being developed. This study describes the influence of the growth rate of N. meningitidis on its macro-molecular composition and its metabolic activity and was determined in chemostat cultures. In the applied range of growth rates, no significant changes in RNA content and protein content with growth rate were observed in N. meningitidis. The DNA content in N. meningitidis was somewhat higher at the highest applied growth rate. The phospholipid and lipopolysaccharide content in N. meningitidis changed with growth rate but no specific trends were observed. The cellular fatty acid composition and the amino acid composition did not change significantly with growth rate. Additionally, it was found that the PorA content in outer membrane vesicles was significantly lower at the highest growth rate. The metabolic fluxes at various growth rates were calculated using flux balance analysis. Errors in fluxes were calculated using Monte Carlo Simulation and the reliability of the calculated flux distribution could be indicated, which has not been reported for this type of analysis. The yield of biomass on substrate (Y(x/s)) and the maintenance coefficient (m(s)) were determined as 0.44 (+/-0.04) g g(-1) and 0.04 (+/-0.02) g g(-1) h(-1), respectively. The growth associated energy requirement (Y(x/ATP)) and the non-growth associated ATP requirement for maintenance (m(ATP)) were estimated as 0.13 (+/-0.04) mol mol(-1) and 0.43 (+/-0.14) mol mol(-1) h(-1), respectively. It was found that the split ratio between the Entner-Doudoroff and the pentose phosphate pathway, the sole glucose utilizing pathways in N. meningitidis, had a minor effect on ATP formation rate but a major

  18. Epinephrine plasma metabolic clearance rates and physiologic thresholds for metabolic and hemodynamic actions in man.

    PubMed Central

    Clutter, W E; Bier, D M; Shah, S D; Cryer, P E

    1980-01-01

    To determine the plasma epinephrine thresholds for its metabolic and hemodynamic actions and plasma epinephrine metabolic clearance rates, 60-min intravenous epinephrine infusions at nominal rates of 0.1, 0.5, 1.0, 2.5, and 5.0 microgram/min were performed in each of six normal human subjects. These 30 infusions resulted in steady-state plasma epinephrine concentrations ranging from 24 to 1,020 pg/ml. Plasma epinephrine thresholds were 50-100 pg/ml for increments in heart rate, 75-125 pg/ml for increments in blood glycerol and systolic blood pressure, 150-200 pg/ml for increments in plasma glucose (the resultant of increments in glucose production and decrements in glucose clearance), blood lactate, blood beta-hydroxybutyrate, and diastolic blood pressure, and greater than 400 pg/ml for early decrements in plasma insulin. Changes in blood alanine, plasma glucagon, plasma growth hormone, and plasma cortisol were not detected. At steady-state plasma epinephrine concentrations of 24-74 pg/ml, values overlapping the basal normal range, the mean (+/-SE) plasma metabolic clearance rate of epinephrine was 52 +/- 4 ml x min-1 x kg-1; this value rose to 89 +/- 6 ml x min-1 x kg-1 (P less than 0.01) at steady-state epinephrine concentrations of 90-1,020 pg/ml. We conclude that in human subjects: (a) the plasma epinephrine thresholds for its hemodynamic and metabolic actions lie within the physiologic range, (b) epinephrine and norepinephrine accelerate their own metabolic clearance, and (c) epinephrine is 10 times more potent than norepinephrine. PMID:6995479

  19. Determinants of intra-specific variation in basal metabolic rate.

    PubMed

    Konarzewski, Marek; Książek, Aneta

    2013-01-01

    Basal metabolic rate (BMR) provides a widely accepted benchmark of metabolic expenditure for endotherms under laboratory and natural conditions. While most studies examining BMR have concentrated on inter-specific variation, relatively less attention has been paid to the determinants of within-species variation. Even fewer studies have analysed the determinants of within-species BMR variation corrected for the strong influence of body mass by appropriate means (e.g. ANCOVA). Here, we review recent advancements in studies on the quantitative genetics of BMR and organ mass variation, along with their molecular genetics. Next, we decompose BMR variation at the organ, tissue and molecular level. We conclude that within-species variation in BMR and its components have a clear genetic signature, and are functionally linked to key metabolic process at all levels of biological organization. We highlight the need to integrate molecular genetics with conventional metabolic field studies to reveal the adaptive significance of metabolic variation. Since comparing gene expressions inter-specifically is problematic, within-species studies are more likely to inform us about the genetic underpinnings of BMR. We also urge for better integration of animal and medical research on BMR; the latter is quickly advancing thanks to the application of imaging technologies and 'omics' studies. We also suggest that much insight on the biochemical and molecular underpinnings of BMR variation can be gained from integrating studies on the mammalian target of rapamycin (mTOR), which appears to be the major regulatory pathway influencing the key molecular components of BMR.

  20. A 12 week aerobic exercise program improves fitness, hepatic insulin sensitivity and glucose metabolism in obese Hispanic adolescents

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The rise in obesity related morbidity in children and adolescents requires urgent prevention and treatment strategies. Strictly controlled exercise programs might be useful tools to improve insulin sensitivity and glucose kinetics. Our objective was to test the hypothesis that a 12-wk aerobic exerci...

  1. Age at first reproduction and growth rate are independent of basal metabolic rate in mammals.

    PubMed

    Lovegrove, Barry G

    2009-05-01

    This study tested an emergent prediction from the Metabolic Theory of Ecology (MTE) that the age at first reproduction (alpha) of a mammal is proportional to the inverse of its mass-corrected basal metabolic rate: alpha proportional (B / M)-1 The hypothesis was tested with multiple regression models of conventional species data and phylogenetically independent contrasts of 121 mammal species. Since age at first reproduction is directly influenced by an individual's growth rate, the hypothesis that growth rate is proportional to BMR was also tested. Although the overall multiple regression model was significant, age at first reproduction was not partially correlated with either body mass, growth rate or BMR. Similarly, growth rate was not correlated with BMR. Thus at least for mammals in general, there is no evidence to support the fundamental premise of the MTE that individual metabolism governs the rate at which energy is converted to growth and reproduction at the species level. The exponents of the BMR allometry calculated using phylogenetic generalized least squares regression models were significantly lower than the three-quarter value predicted by the MTE.

  2. Thyroid Hormones Correlate with Basal Metabolic Rate but Not Field Metabolic Rate in a Wild Bird Species

    PubMed Central

    Welcker, Jorg; Chastel, Olivier; Gabrielsen, Geir W.; Guillaumin, Jerome; Kitaysky, Alexander S.; Speakman, John R.; Tremblay, Yann; Bech, Claus

    2013-01-01

    Thyroid hormones (TH) are known to stimulate in vitro oxygen consumption of tissues in mammals and birds. Hence, in many laboratory studies a positive relationship between TH concentrations and basal metabolic rate (BMR) has been demonstrated whereas evidence from species in the wild is scarce. Even though basal and field metabolic rates (FMR) are often thought to be intrinsically linked it is still unknown whether a relationship between TH and FMR exists. Here we determine the relationship between the primary thyroid hormone triiodothyronine (T3) with both BMR and FMR in a wild bird species, the black-legged kittiwake (Rissa tridactyla). As predicted we found a strong and positive relationship between plasma concentrations of T3 and both BMR and mass-independent BMR with coefficients of determination ranging from 0.36 to 0.60. In contrast there was no association of T3 levels with either whole-body or mass-independent FMR (R2 = 0.06 and 0.02, respectively). In accordance with in vitro studies our data suggests that TH play an important role in modulating BMR and may serve as a proxy for basal metabolism in wild birds. However, the lack of a relationship between TH and FMR indicates that levels of physical activity in kittiwakes are largely independent of TH concentrations and support recent studies that cast doubt on a direct linkage between BMR and FMR. PMID:23437096

  3. Prolonged exposure of mixed aerobic cultures to low temperature and benzalkonium chloride affect the rate and extent of nitrification.

    PubMed

    Yang, Jeongwoo; Tezel, Ulas; Li, Kexun; Pavlostathis, Spyros G

    2015-03-01

    The combined effect of benzalkonium chloride (BAC) and prolonged exposure to low temperature on nitrification was investigated. Ammonia oxidation at 22-24°C by an enriched nitrifying culture was inhibited at increasing BAC concentrations and ceased at 15 mg BAC/L. The non-competitive inhibition coefficient was 1.5±0.9 mg BAC/L. Nitrification tests were conducted without and with BAC at 5mg/L using an aerobic, mixed heterotrophic/nitrifying culture maintained at a temperature range of 24-10°C. Maintaining this culture at 10°C for over one month in the absence of BAC, resulted in slower nitrification kinetics compared to those measured when the culture was first exposed to 10°C. BAC was degraded by the heterotrophic population, but its degradation rate decreased significantly as the culture temperature decreased to 10°C. These results confirm the negative impact of quaternary ammonium compounds on the nitrification process, which is further exacerbated by prolonged, low temperature conditions.

  4. Systems Characterization of Temperature, Ph and Electrical Conductivity in Aerobic Biodegradation of Wheat Biomass at Differing Mixing Rates

    NASA Technical Reports Server (NTRS)

    Calhoun, M.; Trotman, A.; Aglan, H.

    1998-01-01

    The purpose of this preliminary study is to observe and relate the rate of mixing to pH and electrical conductivity in an aerobic, continuously stirred bioreactor. The objective is to use data collected from successive experiments as a means of a system characterization. Tests were conducted to obtain these data using a continuously stirred 20 L Cytostir glass reaction vessel as a bioreactor operated without built-in temperature or pH control. The tests were conducted on the lab bench at ambient temperatures. The substrate in the bioreactor was ground wheat biomass obtained from the Biomass Production Chamber at NASA Kennedy Space Center. In this study, the data reflect characteristics of the native (uninoculated) systems as well as inoculated systems. In the native systems, it was found that pi levels became stable after approximately 2 to 3 days. The electrical conductivity levels for the native systems tended to decrease over time. In contrast, ion activity was increased after the introduction of bacteria into the system. This could be correlated with the release of nutrients, due to the activity of the bacteria. Also, there were slight increases in pH in the inoculated system, a result which is expected for a system with no active pr controls. The data will be used to test a mathematical model in an automated system.

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

    PubMed Central

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

    2015-01-01

    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. PMID:26161636

  6. Effect of applying molasses or inoculants containing homofermentative or heterofermentative bacteria at two rates on the fermentation and aerobic stability of corn silage.

    PubMed

    Huisden, C M; Adesogan, A T; Kim, S C; Ososanya, T

    2009-02-01

    This study determined how the fermentation and aerobic stability of corn silage are affected by treatment with molasses or 2 dual-purpose inoculants applied at or above the recommended rate. Corn forage (DeKalb 69-70) was harvested at 39% dry matter (DM) and ensiled after treatment with no additives (control, CON), molasses (MOL), Buchneri 500 inoculant, or Pioneer 11C33 inoculant. Molasses was applied at 3% of forage DM. Buchneri 500 was applied at the recommended rate of 8 mg/kg fresh forage to supply 1 x 10(5) cfu/g of Pediococcus pentosaceus 12455 and 4 x 10(5) cfu/g of Lactobacillus buchneri 40788 (BB) or at twice the recommended rate (DBB). Pioneer 11C33 inoculant was applied at the recommended rate of 1.1 mg/kg fresh forage to supply 1 x 10(5) cfu/g of a mixture of Lactobacillus plantarum, L. buchneri, and Enteroccocus faecium (PN) or at twice the recommended rate (DPN). Each treatment was applied in quadruplicate and the treated forages were ensiled within 20-L mini silos for 135 d at 18 to 35 degrees C. Molasses-treated silages had greater ash and starch concentrations than CON silages and greater lactate and ethanol concentrations than other silages. Like CON silages, MOL silages had high yeast counts (>10(5) cfu/g); consequently, they deteriorated within 30 h as shown by temperature increase. Inoculant-treated silages had lower lactate to acetate ratios than CON or MOL silages largely because they had greater acetate concentrations. Consequently, all inoculant-treated silages had fewer yeasts (<10(5) cfu/g) and were more stable (>30 h) than CON and MOL silages. When applied at recommended rates, PN and BB had similar effects on silage chemical composition, fermentation, fungal counts, and aerobic stability, except for a lower lactate concentration in PN silages. Concentrations of VFA, and NH(3)-N, pH, and extent of aerobic stability were similar for PN, DPN, BB, and DBB silages. However, lactate concentration was greater in DPN than in PN. In conclusion

  7. Differential baroreflex control of heart rate in sedentary and aerobically fit individuals

    NASA Technical Reports Server (NTRS)

    Smith, S. A.; Querry, R. G.; Fadel, P. J.; Welch-O'Connor, R. M.; Olivencia-Yurvati, A.; Shi, X.; Raven, P. B.

    2000-01-01

    PURPOSE: We compared arterial, aortic, and carotid-cardiac baroreflex sensitivity in eight average fit (maximal oxygen uptake, VO2max = 42.2+/-1.9 mL x kg(-1) x min(-1)) and eight high fit (VO2max = 61.9+/-2.2 mL x kg(-1) x min(-1)) healthy young adults. METHODS: Arterial and aortic (ABR) baroreflex functions were assessed utilizing hypo- and hyper-tensive challenges induced by graded bolus injections of sodium nitroprusside (SN) and phenylephrine (PE), respectively. Carotid baroreflex (CBR) sensitivity was determined using ramped 5-s pulses of both pressure and suction delivered to the carotid sinus via a neck chamber collar, independent of drug administration. RESULTS: During vasoactive drug injection, mean arterial pressure (MAP) was similarly altered in average fit (AF) and high fit (HF) groups. However, the heart rate (HR) response range of the arterial baroreflex was significantly attenuated (P < 0.05) in HF (31+/-4 beats x min(-1)) compared with AF individuals (46+/-4 beats x min(-1)). When sustained neck suction and pressure were applied to counteract altered carotid sinus pressure during SN and PE administration, isolating the ABR response, the response range remained diminished (P < 0.05) in the HF population (24+/-3 beats x min(-1)) compared with the AF group (41+/-4 beats x min(-1)). During CBR perturbation, the HF (14+/-1 beats-min(-1)) and AF (16+/-1 beats-min(-1)) response ranges were similar. The arterial baroreflex response range was significantly less than the simple sum of the CBR and ABR (HF, 38+/-3 beats x min(-1) and AF, 57+/-4 beats x min(-1)) in both fitness groups. CONCLUSIONS: These data confirm that reductions in arterial-cardiac reflex sensitivity are mediated by diminished ABR function. More importantly, these data suggest that the integrative relationship between the ABR and CBR contributing to arterial baroreflex control of HR is inhibitory in nature and not altered by exercise training.

  8. Strength and aerobic training in overweight females in Gdansk, Poland

    PubMed Central

    Sawczyn, Stanisław; Mishchenko, Viktor; Moska, Waldemar; Sawczyn, Michał; Jagiełło, Marina; Kuehne, Tatiana; Nowak, Robert; Cięszczyk, Paweł

    2015-01-01

    We compared the effects of 16-week-training on rest metabolic rate, aerobic power, and body fat, and the post-exercise effects upon rest oxygen uptake and respiratory exchange ratio in overweight middle-aged females. Twenty nine overweight women (BMI 29.9 ± 1.2 kg*m−2) participated in training (3 days a week). The subjects were divided onto groups of aerobic (AT) and strength (ST) training. The results showed that the total body mass decrease and VO2 max increase did not differ in both groups. Decrease in waist circumference after 16 weeks was higher in the ST group. In the ST group fat-free mass increased during the first 8 weeks. Rest metabolic rate was increased significantly at 16th week compared to initial value in ST group only. Significant increase in post-exercise resting VO2 and respiratory exchange ratio at 12 and 36 h was observed after the strength training session only. Increase in rest metabolic rate and post-exercise rest energy expenditure occurred after strength training but not after aerobic training despite the similar increase in aerobic power. The effect of 8–16 weeks of strength training on body mass decrease was higher in comparison to aerobic training. PMID:28352690

  9. Effects of a heart rate-based recovery period on hormonal, neuromuscular, and aerobic performance responses during 7 weeks of strength training in men.

    PubMed

    Piirainen, Jarmo M; Tanskanen, Minna; Nissilä, Juuso; Kaarela, Juha; Väärälä, Ari; Sippola, Niina; Linnamo, Vesa

    2011-08-01

    The purpose of this study was to compare hormonal, neuromuscular, and aerobic performance changes between a constant 2-minute interset recovery time and an interset recovery time based on individual heart rate (HR) responses during a 7-week (3 sessions per week, 3 × 10 repetition maximum [RM]) hypertrophic strength training period. The HR-dependent recovery time was determined with a Polar FT80 HR monitor, whereas the control groups used constant 2-minute periods between sets. From 24 male subjects who were divided in 2 equal groups, 21 completed the study (FT80, n = 12; CONTROL, n = 9). Serum blood samples analyzed for testosterone (TES) and cortisol (COR) were taken before and after the 7-week training period at rest. Concentric knee extension 1RM was measured before, after 4 weeks, and at the end of the training period. Concentric knee extension and knee flexion 10RM, central activation ratio (CAR), and maxVO2 were measured before and after the training. Serum TES concentrations were significantly higher after the training period in FT80 (p < 0.001), whereas no significant changes were observed in the CONTROL. Serum COR and maxVO2 were unchanged in both groups. In FT80 (p < 0.001), the increase in 10RM was higher (p < 0.05) than in CONTROL (p < 0.001). Central activation ratio increased in both groups, with the significant increase observed in FT80 (p < 0.05). The higher TES responses, 10RM, and CAR development in FT80 suggest that an HR-based recovery period system of the FT80 may be more efficient in this type of hypertrophic strength training (3 × 10RM). The protocol in this study may be considered as a metabolic training cycle that coaches and trainers can use within a longer periodized training program.

  10. Male mealworm beetles increase resting metabolic rate under terminal investment.

    PubMed

    Krams, I A; Krama, T; Moore, F R; Kivleniece, I; Kuusik, A; Freeberg, T M; Mänd, R; Rantala, M J; Daukšte, J; Mänd, M

    2014-03-01

    Harmful parasite infestation can cause energetically costly behavioural and immunological responses, with the potential to reduce host fitness and survival. It has been hypothesized that the energetic costs of infection cause resting metabolic rate (RMR) to increase. Furthermore, under terminal investment theory, individuals exposed to pathogens should allocate resources to current reproduction when life expectancy is reduced, instead of concentrating resources on an immune defence. In this study, we activated the immune system of Tenebrio molitor males via insertion of nylon monofilament, conducted female preference tests to estimate attractiveness of male odours and assessed RMR and mortality. We found that attractiveness of males coincided with significant down-regulation of their encapsulation response against a parasite-like intruder. Activation of the immune system increased RMR only in males with heightened odour attractiveness and that later suffered higher mortality rates. The results suggest a link between high RMR and mortality and support terminal investment theory in T. molitor.

  11. An increase in minimum metabolic rate and not activity explains field metabolic rate changes in a breeding seabird.

    PubMed

    Green, J A; Aitken-Simpson, E J; White, C R; Bunce, A; Butler, P J; Frappell, P B

    2013-05-01

    The field metabolic rate (FMR) of a free-ranging animal can be considered as the sum of its maintenance costs (minimum metabolic rate, MMR) and additional costs associated with thermoregulation, digestion, production and activity. However, the relationships between FMR and BMR and how they relate to behaviour and extrinsic influences is not clear. In seabirds, FMR has been shown to increase during the breeding season. This is presumed to be the result of an increase in foraging activity, stimulated by increased food demands from growing chicks, but few studies have investigated in detail the factors that underlie these increases. We studied free-ranging Australasian gannets (Morus serrator) throughout their 5 month breeding season, and evaluated FMR, MMR and activity-related metabolic costs on a daily basis using the heart rate method. In addition, we simultaneously recorded behaviour (flying and diving) in the same individuals. FMR increased steadily throughout the breeding season, increasing by 11% from the incubation period to the long chick-brooding period. However, this was not accompanied by either an increase in flying or diving behaviour, or an increase in the energetic costs of activity. Instead, the changes in FMR could be explained exclusively by a progressive increase in MMR. Seasonal changes in MMR could be due to a change in body composition or a decrease in body condition associated with changing the allocation of resources between provisioning adults and growing chicks. Our study highlights the importance of measuring physiological parameters continuously in free-ranging animals in order to understand fully the mechanisms underpinning seasonal changes in physiology and behaviour.

  12. Temperature dependences of growth rates and carrying capacities of marine bacteria depart from metabolic theoretical predictions.

    PubMed

    Huete-Stauffer, Tamara Megan; Arandia-Gorostidi, Nestor; Díaz-Pérez, Laura; Morán, Xosé Anxelu G

    2015-10-01

    Using the metabolic theory of ecology (MTE) framework, we evaluated over a whole annual cycle the monthly responses to temperature of the growth rates (μ) and carrying capacities (K) of heterotrophic bacterioplankton at a temperate coastal site. We used experimental incubations spanning 6ºC with bacterial physiological groups identified by flow cytometry according to membrane integrity (live), nucleic acid content (HNA and LNA) and respiratory activity (CTC+). The temperature dependence of μ at the exponential phase of growth was summarized by the activation energy (E), which was variable (-0.52 to 0.72 eV) but followed a seasonal pattern, only reaching the hypothesized value for aerobic heterotrophs of 0.65 eV during the spring bloom for the most active bacterial groups (live, HNA, CTC+). K (i.e. maximum experimental abundance) peaked at 4 × 10(6) cells mL(-1) and generally covaried with μ but, contrary to MTE predictions, it did not decrease consistently with temperature. In the case of live cells, the responses of μ and K to temperature were positively correlated and related to seasonal changes in substrate availability, indicating that the responses of bacteria to warming are far from homogeneous and poorly explained by MTE at our site.

  13. Metabolism and aging: effects of cold exposure on metabolic rate, body composition, and longevity in mice.

    PubMed

    Vaanholt, Lobke M; Daan, Serge; Schubert, Kristin A; Visser, G Henk

    2009-01-01

    The proposition that increased energy expenditure shortens life has a long history. The rate-of-living theory (Pearl 1928 ) states that life span and average mass-specific metabolic rate are inversely proportional. Originally based on interspecific allometric comparisons between species of mammals, the theory was later rejected on the basis of comparisons between taxa (e.g., birds have higher metabolic rates than mammals of the same size and yet live longer). It has rarely been experimentally tested within species. Here, we investigated the effects of increased energy expenditure, induced by cold exposure, on longevity in mice. Longevity was measured in groups of 60 male mice maintained at either 22 degrees C (WW) or 10 degrees C (CC) throughout adult life. Forty additional mice were maintained at both of these temperatures to determine metabolic rate (by stable isotope turnover, gas exchange, and food intake) as well as the mass of body and organs of subsets of animals at four different ages. Because energy expenditure might affect longevity by either accumulating damage or by instantaneously affecting mortality rate, we included a third group of mice exposed to 10 degrees C early in life and to 22 degrees C afterward (CW). Exposure to cold increased mean daily energy expenditure by ca. 48% (from 47.8 kJ d(-1) in WW to 70.6 kJ d(-1) in CC mice, with CW intermediate at 59.9 kJ d(-1)). However, we observed no significant differences in median life span among the groups (WW, 832 d; CC, 834 d; CW, 751 d). CC mice had reduced body mass (lifetime mean 30.7 g) compared with WW mice (33.8 g), and hence their lifetime energy potential (LEP) per gram whole-body mass had an even larger excess than per individual. Greenberg ( 1999 ) has pointed out that the size of the energetically costly organs, rather than that of the whole body, may be relevant for the rate-of-living idea. We therefore expressed LEP also in terms of energy expenditure per gram dry lean mass or per gram

  14. Physiological increments in epinephrine stimulate metabolic rate in humans.

    PubMed

    Staten, M A; Matthews, D E; Cryer, P E; Bier, D M

    1987-09-01

    Markedly elevated plasma epinephrine is known to increase metabolic rate (MR), but such levels of epinephrine are encountered infrequently in normal free-living subjects. We studied whether epinephrine levels common in usual daily activities can affect MR and thus possibly regulate caloric expenditure. To aid definition of a MR threshold, we first measured the hourly and daily variation in MR within individuals by measuring the MR of four individuals by indirect calorimetry for 6 h on six separate occasions without any intervention. We found that hour-to-hour variation (2.0 +/- 0.9%) and the day-to-day variation (2.7 +/- 0.9%) were low, thus allowing confident detection of small increments in metabolic rate during epinephrine infusion. To define a threshold for epinephrine's effect to increase MR, we studied five normal-weight postabsorptive young men on four separate occasions. During the 1st h of each 5-h study period, saline was infused intravenously. Then, during the subsequent 4 h, subjects received intravenous infusion of saline or epinephrine at 0.1, 0.5, and 1.0 microgram/min (randomized). A significant increase in MR (3.6 +/- 1.0% SE) was measured with the lowest epinephrine infusion rate (venous plasma concentration, 94 +/- 32 pg/ml). The increases in MR correlated (r = 0.85, P less than 0.001) with increases in plasma epinephrine. The threshold concentration (upper 95% confidence limit) of epinephrine to affect MR was 90 pg/ml, a concentration frequently occurring in daily life. Thus epinephrine may play an important role in weight maintenance by affecting energy expenditure.

  15. Specific heat flow rate: an on-line monitor and potential control variable of specific metabolic rate in animal cell culture that combines microcalorimetry with dielectric spectroscopy.

    PubMed

    Guan, Y; Evans, P M; Kemp, R B

    1998-06-05

    One of the requirements for enhanced productivity by the animal culture systems used in biotechnology is the direct assessment of the metabolic rate by on-line biosensors. Based on the fact that cell growth is associated with an enthalpy change, it is shown that the specific heat flow rate is stoichiometrically related to the net specific rates of substrates, products, and indeed to specific growth rate, and therefore a direct reflection of metabolic rate. Heat flow rate measured by conduction calorimetry has a technical advantage over estimates for many material flows which require assays at a minimum of two discrete times to give the rate. In order to make heat flow rate specific to the amount of the living cellular system, it would be advantageous to divide it by viable biomass. This requirement has been fulfilled by combining a continuous flow microcalorimeter ex situ with a dielectric spectroscope in situ, the latter measuring the viable cell mass volume fraction. The quality of the resulting biosensor for specific heat flow rate was illustrated using batch cultures of Chinese hamster ovary cells (CHO 320) producing recombinant human interferon-gamma (IFN-gamma) during growth in a stirred tank bioreactor under fully aerobic conditions. The measuring scatter of the probe was decreased significantly by applying the moving average technique to the two participant signals. It was demonstrated that the total metabolic rate of the cells, as indicated by the specific heat flow rate sensor, decreased with increasing time in batch culture, coincident with the decline in the two major substrates, glucose and glutamine, and the accumulation of the by-products, ammonia and lactate. Furthermore, the specific heat flow rate was an earlier indicator of substrate depletion than the flow rate alone. The calorimetric-respirometric ratio showed the intensive participation of anaerobic processes during growth and the related IFN-gamma production. Specific heat flow rate was

  16. Effects of high-intensity interval versus continuous moderate-intensity aerobic exercise on apoptosis, oxidative stress and metabolism of the infarcted myocardium in a rat model.

    PubMed

    Lu, Kai; Wang, Li; Wang, Changying; Yang, Yuan; Hu, Dayi; Ding, Rongjing

    2015-08-01

    The optimal aerobic exercise training (AET) protocol for patients following myocardial infarction (MI) has remained under debate. The present study therefore aimed to compare the effects of continuous moderate-intensity training (CMT) and high-intensity interval training (HIT) on cardiac functional recovery, and to investigate the potential associated mechanisms in a post-MI rat model. Female Sprague Dawley rats (8-10 weeks old) undergoing MI or sham surgery were subsequently submitted to CMT or HIT, or kept sedentary for eight weeks. Prior to and following AET, echocardiographic parameters and exercise capacity of the rats were measured. Western blotting was used to evaluate the levels of apoptosis and associated signaling pathway protein expression. The concentrations of biomarkers of oxidative stress were also determined by ELISA assay. Messenger (m)RNA levels and activity of the key enzymes for glycolysis and fatty acid oxidation, as well as the rate of adenosine triphosphate (ATP) synthesis, were also measured. Compared with the MI group, exercise capacity and cardiac function were significantly improved following AET, particularly following HIT. Left ventricular ejection fraction and fraction shortening were further improved in the MI-HIT group in comparison to that of the MI-CMT group. The two forms of AET almost equally attenuated apoptosis of the post-infarction myocardium. CMT and HIT also alleviated oxidative stress by decreasing the concentration of malondialdehyde and increasing the concentration of superoxide dismutase and glutathione peroxidase (GPx). In particular, HIT induced a greater increase in the concentration of GPx than that of CMT. AET, and HIT in particular, significantly increased the levels of mRNA and the maximal activity of phosphofructokinase-1 and carnitine palmitoyl transferase-1, as well as the maximal ratio of ATP synthesis. In addition, compared with the MI group, the expression of signaling proteins PI3K, Akt, p38mapk and AMPK

  17. Metabolic and Physical Control of Cell Elongation Rate

    PubMed Central

    Green, P. B.; Erickson, R. O.; Buggy, J.

    1971-01-01

    Several levels of control of elongation rate are revealed through the detailed study of responses of the Nitella internode to abrupt shifts in turgor. The immediate response, which apparently reflects the physical state of the cell, is approximately described by the equation r = (P — Y)m where r is rate, P is pressure, Y is the wall's yielding threshold, and m is related to the wall's apparent fluidity (reciprocal viscosity). Because P and Y are in the range 5 to 6 atmospheres, and (P — Y) is roughly 0.2 atmosphere, elongation rate is initially extremely sensitive to changes in P. A small step-down in turgor (0.7 atmosphere) stops growth, and a similar rise greatly accelerates it. These initial responses are, however, soon (15 minutes) compensated by changes in Y. An apparent metabolism-dependent reaction (azide-sensitive) lowers Y; strain hardening (azide-insensitive) raises it. These two opposing processes, acting on Y, serve as a governor on (P — Y), tending to maintain it at a given value despite changes in P. This ability to compensate is itself a function of turgor. Turgor step-downs are less and less well compensated, leading to lower rate, as turgor falls from 5 atmospheres to about 2 atmospheres where growth appears not to resume. This is the lowest attainable yield value, Y1. The turgor dependency of compensation reflects a turgor requirement of the Y-lowering (“wall-softening”) process. Thus the relation between steady state, rs, and turgor is an indirect one, derived from time-dependent alterations of the cell wall. This relationship superficially resembles the instantaneously valid one in that, roughly, rs = (P — Y1)ms. Y1 and ms, however, have much lower values than Y and m. The duality of the elongation rate versus turgor relation and the prominent role of Y in regulating rate are the major features of growth control in Nitella. PMID:16657635

  18. Impact of combined resistance and aerobic exercise training on branched-chain amino acid turnover, glycine metabolism and insulin sensitivity in overweight humans

    PubMed Central

    Glynn, Erin L.; Piner, Lucy W.; Huffman, Kim M.; Slentz, Cris A.; Elliot-Penry, Lorraine; AbouAssi, Hiba; White, Phillip J.; Bain, James R.; Muehlbauer, Michael J.; Ilkayeva, Olga R.; Stevens, Robert D.; Porter Starr, Kathryn N.; Bales, Connie W.; Volpi, Elena; Brosnan, M. Julia; Trimmer, Jeff K.; Rolph, Timothy P.

    2016-01-01

    Aims/hypotheses Obesity is associated with decreased insulin sensitivity (IS) and elevated plasma branched-chain amino acids (BCAAs). The purpose of this study was to investigate the relationship between BCAA metabolism and IS in overweight (OW) individuals during exercise intervention. Methods Whole-body leucine turnover, IS by hyperinsulinaemic–euglycaemic clamp, and circulating and skeletal muscle amino acids, branched-chain α-keto acids and acylcarnitines were measured in ten healthy controls (Control) and nine OW, untrained, insulin-resistant individuals (OW-Untrained). OW-Untrained then underwent a 6 month aerobic and resistance exercise programme and repeated testing (OW-Trained). Results IS was higher in Control vs OW-Untrained and increased significantly following exercise. IS was lower in OW-Trained vs Control expressed relative to body mass, but was not different from Control when normalised to fat-free mass (FFM). Plasma BCAAs and leucine turnover (relative to FFM) were higher in OW-Untrained vs Control, but did not change on average with exercise. Despite this, within individuals, the decrease in molar sum of circulating BCAAs was the best metabolic predictor of improvement in IS. Circulating glycine levels were higher in Control and OW-Trained vs OW-Untrained, and urinary metabolic profiling suggests that exercise induces more efficient elimination of excess acyl groups derived from BCAA and aromatic amino acid (AA) metabolism via formation of urinary glycine adducts. Conclusions/interpretation A mechanism involving more efficient elimination of excess acyl groups derived from BCAA and aromatic AA metabolism via glycine conjugation in the liver, rather than increased BCAA disposal through oxidation and turnover, may mediate interactions between exercise, BCAA metabolism and IS. Trial registration Clinicaltrials.gov NCT01786941 PMID:26254576

  19. AKT1 G205T genotype influences obesity-related metabolic phenotypes and their responses to aerobic exercise training in older Caucasians.

    PubMed

    McKenzie, Jennifer A; Witkowski, Sarah; Ludlow, Andrew T; Roth, Stephen M; Hagberg, James M

    2011-03-01

    As part of the insulin signalling pathway, Akt influences growth and metabolism. The AKT1 gene G205T (rs1130214) polymorphism has potential functional effects. Thus, we determined whether the G205T polymorphism influences metabolic variables and their responses to aerobic exercise training. Following dietary stabilization, healthy, sedentary, 50- to 75-year-old Caucasian men (n = 51) and women (n = 58) underwent 6 months of aerobic exercise training. Before and after completing the intervention, dual-energy X-ray absorptiometry was used to measure percentage body fat, computed tomography to measure visceral and subcutaneous fat, and oral glucose tolerance testing to measure glucose total area under the curve (AUC), insulin AUC and insulin sensitivity. Taqman assay was used to determine AKT1 G205T genotypes. At baseline, men with the GG genotype (n = 29) had lower maximal oxygen consumption (VO2 max) values (P = 0.026) and higher percentage body fat (P = 0.046), subcutaneous fat (P = 0.021) and insulin AUC (P = 0.003) values than T allele carriers (n = 22). Despite their rather disadvantageous starting values, men with the GG genotype seemed to respond to exercise training more robustly than men with the T allele, highlighted by significantly greater fold change improvements in insulin AUC (P = 0.012) and glucose AUC (P = 0.035). Although the GG group also significantly improved VO2 max with training, the change in VO2 max was not as great as that of the T allele carriers (P = 0.037). In contrast, after accounting for hormone replacement therapy use, none of the variables differed in the women at baseline. As a result of exercise training, women with the T allele (n = 20) had greater fold change improvements in fasting glucose (P = 0.011), glucose AUC (P = 0.017) and insulin sensitivity (P = 0.044) than GG genotype women (n = 38). Our results suggest that the AKT1 G205T polymorphism influences metabolic variables and their responses to aerobic exercise training in

  20. Metabolic rate covaries with fitness and the pace of the life history in the field.

    PubMed

    Pettersen, Amanda K; White, Craig R; Marshall, Dustin J

    2016-05-25

    Metabolic rate reflects the 'pace of life' in every organism. Metabolic rate is related to an organism's capacity for essential maintenance, growth and reproduction-all of which interact to affect fitness. Although thousands of measurements of metabolic rate have been made, the microevolutionary forces that shape metabolic rate remain poorly resolved. The relationship between metabolic rate and components of fitness are often inconsistent, possibly because these fitness components incompletely map to actual fitness and often negatively covary with each other. Here we measure metabolic rate across ontogeny and monitor its effects on actual fitness (lifetime reproductive output) for a marine bryozoan in the field. We also measure key components of fitness throughout the entire life history including growth rate, longevity and age at the onset of reproduction. We found that correlational selection favours individuals with higher metabolic rates in one stage and lower metabolic rates in the other-individuals with similar metabolic rates in each developmental stage displayed the lowest fitness. Furthermore, individuals with the lowest metabolic rates lived for longer and reproduced more, but they also grew more slowly and took longer to reproduce initially. That metabolic rate is related to the pace of the life history in nature has long been suggested by macroevolutionary patterns but this study reveals the microevolutionary processes that probably generated these patterns.

  1. Metabolic analyzer. [for measuring metabolic rate and breathing dynamics of human beings

    NASA Technical Reports Server (NTRS)

    Rummel, J. A.; Perry, C. L. (Inventor)

    1974-01-01

    An apparatus is described for the measurement of metabolic rate and breathing dynamics in which inhaled and exhaled breath are sensed by sealed, piston-displacement type spirometers. These spirometers electrically measure the volume of inhaled and exhaled breath. A mass spectrometer analyzes simultaneously for oxygen, carbon dioxide, nitrogen and water vapor. Computation circuits are responsive to the outputs of the spirometers, mass spectrometer, temperature, pressure and timing signals and compute oxygen consumption, carbon dioxide production, minute volume and respiratory exchange ratio. A selective indicator provides for read-out of these data at predetermined cyclic intervals.

  2. Heart Rate Recovery and Variability Following Combined Aerobic and Resistance Exercise Training in Adults with and without Down Syndrome

    ERIC Educational Resources Information Center

    Mendonca, Goncalo V.; Pereira, Fernando D.; Fernhall, Bo

    2013-01-01

    Persons with Down syndrome (DS) are at high risk for cardiovascular morbidity and mortality, and there is compelling evidence of autonomic dysfunction in these individuals. The main purpose of this study was to determine whether a combined aerobic and resistance exercise intervention produces similar results in cardiac autonomic function between…

  3. Change in body composition following a 15-week, heart rate monitored aerobic exercise program: The TIGER study

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The joint goals of the Training Interventions and Genetics of Exercise Response (TIGER) study are to introduce sedentary college-age individuals to regular exercise and identify genetic factors that influence physiologic response to aerobic exercise training. The purpose of the study was to examine ...

  4. 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.

  5. Assessing Metabolic Syndrome Through Increased Heart Rate During Exercise.

    PubMed

    Sadeghi, Masoumeh; Gharipour, Mojgan; Nezafati, Pouya; Shafie, Davood; Aghababaei, Esmaeil; Sarrafzadegan, Nizal

    2016-11-01

    The present study aimed to assess changes in resting and maximum heart rates as primary indicators of cardiac autonomic function in metabolic syndrome (MetS) patients and to determine their value for discriminating MetS from non-MetS. 468 participants were enrolled in this cross-sectional study and assessed according to the updated adult treatment panel III (ATP-III) definition of MetS. Resting and maximum heart rates were recorded following the Bruce protocol during an exercise. A receiver operating characteristic (ROC) curve was used to identify the best cutoff point for discriminating MetS from the non-MetS state. 194 participants (41.5%) were diagnosed as MetS. The mean resting heart rate (RHR) was not statistically different between the two groups (P=0.078). However, the mean maximum heart (MHR) rate was considerably higher in participants with MetS (142.37±14.84 beats per min) compared to the non-MetS group (134.62±21.63 beats per min) (P<0.001). In the MetS group, the MHR was positively correlated with the serum triglyceride level (β=0.185, P=0.033) and was inversely associated with age (β=-0.469, P<0.001). The MHR had a moderate value for discriminating MetS from the non-MetS state (c=0.580, P=0.004) with the optimal cutoff point of 140 beats per min. In MetS patients, the MHR was significantly greater compared to non-MetS subjects and was directly correlated with serum triglyceride levels and inversely with advanced age. Moreover, MHR can be used as a suspicious indicator for identifying MetS.

  6. Effects of intraspecific variation in reproductive traits, pectoral fin use and burst swimming on metabolic rates and swimming performance in the Trinidadian guppy (Poecilia reticulata).

    PubMed

    Svendsen, Jon C; Banet, Amanda I; Christensen, Rune H B; Steffensen, John F; Aarestrup, Kim

    2013-09-15

    There is considerable intraspecific variation in metabolic rates and locomotor performance in aquatic ectothermic vertebrates; however, the mechanistic basis remains poorly understood. Using pregnant Trinidadian guppies (Poecilia reticulata), a live-bearing teleost, we examined the effects of reproductive traits, pectoral fin use and burst-assisted swimming on swimming metabolic rate, standard metabolic rate (O2std) and prolonged swimming performance (Ucrit). Reproductive traits included reproductive allocation and pregnancy stage, the former defined as the mass of the reproductive tissues divided by the total body mass. Results showed that the metabolic rate increased curvilinearly with swimming speed. The slope of the relationship was used as an index of swimming cost. There was no evidence that reproductive traits correlated with swimming cost, O2std or Ucrit. In contrast, data revealed strong effects of pectoral fin use on swimming cost and Ucrit. Poecilia reticulata employed body-caudal fin (BCF) swimming at all tested swimming speeds; however, fish with a high simultaneous use of the pectoral fins exhibited increased swimming cost and decreased Ucrit. These data indicated that combining BCF swimming and pectoral fin movement over a wide speed range, presumably to support swimming stability and control, is an inefficient swimming behaviour. Finally, transition to burst-assisted swimming was associated with an increase in aerobic metabolic rate. Our study highlights factors other than swimming speed that affect swimming cost and suggests that intraspecific diversity in biomechanical performance, such as pectoral fin use, is an important source of variation in both locomotor cost and maximal performance.

  7. Covariation of metabolic rates and cell size in coccolithophores

    NASA Astrophysics Data System (ADS)

    Aloisi, G.

    2015-08-01

    Coccolithophores are sensitive recorders of environmental change. The size of their coccosphere varies in the ocean along gradients of environmental conditions and provides a key for understanding the fate of this important phytoplankton group in the future ocean. But interpreting field changes in coccosphere size in terms of laboratory observations is hard, mainly because the marine signal reflects the response of multiple morphotypes to changes in a combination of environmental variables. In this paper I examine the large corpus of published laboratory experiments with coccolithophores looking for relations between environmental conditions, metabolic rates and cell size (a proxy for coccosphere size). I show that growth, photosynthesis and, to a lesser extent, calcification covary with cell size when pCO2, irradiance, temperature, nitrate, phosphate and iron conditions change. With the exception of phosphate and temperature, a change from limiting to non-limiting conditions always results in an increase in cell size. An increase in phosphate or temperature (below the optimum temperature for growth) produces the opposite effect. The magnitude of the coccosphere-size changes observed in the laboratory is comparable to that observed in the ocean. If the biological reasons behind the environment-metabolism-size link are understood, it will be possible to use coccosphere-size changes in the modern ocean and in marine sediments to investigate the fate of coccolithophores in the future ocean. This reasoning can be extended to the size of coccoliths if, as recent experiments are starting to show, coccolith size reacts to environmental change proportionally to coccosphere size. The coccolithophore database is strongly biased in favour of experiments with the coccolithophore Emiliania huxleyi (E. huxleyi; 82 % of database entries), and more experiments with other species are needed to understand whether these observations can be extended to coccolithophores in general. I

  8. The Potential Role of Aerobic Exercise-Induced Pentraxin 3 on Obesity-Related Inflammation and Metabolic Dysregulation

    PubMed Central

    Acevedo, Edmund O.

    2017-01-01

    Obesity is defined as the excess accumulation of intra-abdominal body fat, resulting in a state of chronic, low-grade proinflammation that can directly contribute to the development of insulin resistance. Pentraxin 3 (PTX3) is an acute-phase protein that is expressed by a variety of tissue and cell sources and provides an anti-inflammatory property to downregulate the production of proinflammatory cytokines, in particular interleukin-1 beta and tumor necrosis factor alpha. Although PTX3 may therapeutically aid in altering the proinflammatory milieu in obese individuals, and despite elevated expression of PTX3 mRNA observed in adipose tissue, the circulating level of PTX3 is reduced with obesity. Interestingly, aerobic activity has been demonstrated to elevate PTX3 levels. Therefore, the purpose of this review is to discuss the therapeutic potential of PTX3 to positively regulate obesity-related inflammation and discuss the proposition for utilizing aerobic exercise as a nonpharmacological anti-inflammatory treatment strategy to enhance circulating PTX3 concentrations in obese individuals.

  9. Mammalian metabolic rates in the hottest fish on earth

    PubMed Central

    Wood, Chris M.; Brix, Kevin V.; De Boeck, Gudrun; Bergman, Harold L.; Bianchini, Adalto; Bianchini, Lucas F.; Maina, John N.; Johannsson, Ora E.; Kavembe, Geraldine D.; Papah, Michael B.; Letura, Kisipan M.; Ojoo, Rodi O.

    2016-01-01

    The Magadi tilapia, Alcolapia grahami, a small cichlid fish of Lake Magadi, Kenya lives in one of the most challenging aquatic environments on earth, characterized by very high alkalinity, unusual water chemistry, and extreme O2, ROS, and temperature regimes. In contrast to most fishes which live at temperatures substantially lower than the 36–40 °C of mammals and birds, an isolated population (South West Hot Springs, SWHS) of Magadi tilapia thrives in fast-flowing hotsprings with daytime highs of 43 °C and night-time lows of 32 °C. Another population (Fish Springs Lagoon, FSL) lives in a lagoon with fairly stable daily temperatures (33–36 °C). The upper critical temperatures (Ctmax) of both populations are very high; moreover the SWHS tilapia exhibit the highest Ctmax (45.6 °C) ever recorded for a fish. Routine rates of O2 consumption (MO2) measured on site, together with MO2 and swimming performance at 25, 32, and 39 °C in the laboratory, showed that the SWHS tilapia exhibited the greatest metabolic performance ever recorded in a fish. These rates were in the basal range of a small mammal of comparable size, and were all far higher than in the FSL fish. The SWHS tilapia represents a bellwether organism for global warming. PMID:27257105

  10. Gravity, Body Mass and Composition, and Metabolic Rate

    NASA Technical Reports Server (NTRS)

    Pace, N.; Smith, A. H.

    1985-01-01

    Metabolic rate and body composition as a function of sex and age were defined in 5 species of common laboratory mammals, the mouse, hamster, rat, guinea pig and rabbit. Oxygen consumption and carbon dioxide production rates were measured individually in 6 male and 6 female animals for each of 8 age cohorts ranging from 1 month to 2 years, and for each of the species. From the results it is evident that among these small mammals there is no indication of scaling of muscularity to body size, despite the 100-fold difference in body mass represented by the skeletal musculature seems to reach a pronounced peak value at age 2 to 3 months and then declines, the fraction of the fat-free body represented by other body components in older animals must increase complementarily. Under normal gravity conditions muscularity in small laboratory mammals displays large, systematic variation as a function both of species and age. This variation must be considered when such animals are subjects of experiments to study the effects of altered gravitational loading on the skeletal musculature of the mammal.

  11. Evolutionary Rate Heterogeneity of Primary and Secondary Metabolic Pathway Genes in Arabidopsis thaliana.

    PubMed

    Mukherjee, Dola; Mukherjee, Ashutosh; Ghosh, Tapash Chandra

    2015-11-10

    Primary metabolism is essential to plants for growth and development, and secondary metabolism helps plants to interact with the environment. Many plant metabolites are industrially important. These metabolites are produced by plants through complex metabolic pathways. Lack of knowledge about these pathways is hindering the successful breeding practices for these metabolites. For a better knowledge of the metabolism in plants as a whole, evolutionary rate variation of primary and secondary metabolic pathway genes is a prerequisite. In this study, evolutionary rate variation of primary and secondary metabolic pathway genes has been analyzed in the model plant Arabidopsis thaliana. Primary metabolic pathway genes were found to be more conserved than secondary metabolic pathway genes. Several factors such as gene structure, expression level, tissue specificity, multifunctionality, and domain number are the key factors behind this evolutionary rate variation. This study will help to better understand the evolutionary dynamics of plant metabolism.

  12. Environment, Migratory Tendency, Phylogeny and Basal Metabolic Rate in Birds

    PubMed Central

    Jetz, Walter; Freckleton, Robert P.; McKechnie, Andrew E.

    2008-01-01

    Basal metabolic rate (BMR) represents the minimum maintenance energy requirement of an endotherm and has far-reaching consequences for interactions between animals and their environments. Avian BMR exhibits considerable variation that is independent of body mass. Some long-distance migrants have been found to exhibit particularly high BMR, traditionally interpreted as being related to the energetic demands of long-distance migration. Here we use a global dataset to evaluate differences in BMR between migrants and non-migrants, and to examine the effects of environmental variables. The BMR of migrant species is significantly higher than that of non-migrants. Intriguingly, while the elevated BMR of migrants on their breeding grounds may reflect the metabolic machinery required for long-distance movements, an alternative (and statistically stronger) explanation is their occupation of predominantly cold high-latitude breeding areas. Among several environmental predictors, average annual temperature has the strongest effect on BMR, with a 50% reduction associated with a 20°C gradient. The negative effects of temperature variables on BMR hold separately for migrants and non-migrants and are not due their different climatic associations. BMR in migrants shows a much lower degree of phylogenetic inertia. Our findings indicate that migratory tendency need not necessarily be invoked to explain the higher BMR of migrants. A weaker phylogenetic signal observed in migrants supports the notion of strong phenotypic flexibility in this group which facilitates migration-related BMR adjustments that occur above and beyond environmental conditions. In contrast to the findings of previous analyses of mammalian BMR, primary productivity, aridity or precipitation variability do not appear to be important environmental correlates of avian BMR. The strong effects of temperature-related variables and varying phylogenetic effects reiterate the importance of addressing both broad-scale and

  13. Growth trajectory influences temperature preference in fish through an effect on metabolic rate.

    PubMed

    Killen, Shaun S

    2014-11-01

    Most animals experience temperature variations as they move through the environment. For ectotherms, in particular, temperature has a strong influence on habitat choice. While well studied at the species level, less is known about factors affecting the preferred temperature of individuals; especially lacking is information on how physiological traits are linked to thermal preference and whether such relationships are affected by factors such feeding history and growth trajectory. This study examined these issues in the common minnow Phoxinus phoxinus, to determine the extent to which feeding history, standard metabolic rate (SMR) and aerobic scope (AS), interact to affect temperature preference. Individuals were either: 1) food deprived (FD) for 21 days, then fed ad libitum for the next 74 days; or 2) fed ad libitum throughout the entire period. All animals were then allowed to select preferred temperatures using a shuttle-box, and then measured for SMR and AS at 10 °C, estimated by rates of oxygen uptake. Activity within the shuttle-box under a constant temperature regime was also measured. In both FD and control fish, SMR was negatively correlated with preferred temperature. The SMR of the FD fish was increased compared with the controls, probably due to the effects of compensatory growth, and so these growth-compensated fish preferred temperatures that were on average 2.85 °C cooler than controls fed a maintenance ration throughout the study. Fish experiencing compensatory growth also displayed a large reduction in activity. In growth-compensated fish and controls, activity measured at 10 °C was positively correlated with preferred temperature. Individual fish prefer temperatures that vary predictably with SMR and activity level, which are both plastic in response to feeding history and growth trajectories. Cooler temperatures probably allow individuals to reduce maintenance costs and divert more energy towards growth. A reduction in SMR at cooler

  14. Elevated resting heart rate is associated with the metabolic syndrome

    PubMed Central

    Rogowski, Ori; Steinvil, Arie; Berliner, Shlomo; Cohen, Michael; Saar, Nili; Kliuk Ben-Bassat, Orit; Shapira, Itzhak

    2009-01-01

    Background Increased resting heart rate (RHR) may be associated with increased cardiovascular morbidity. Our aim was to explore the possibility that increased RHR is associated with the prevalence of the metabolic syndrome (MetS) in a sample of apparently healthy individuals and those with cardiovascular risk factors. Methods We performed a cross-sectional analysis in a large sample of apparently healthy individuals who attended a general health screening program and agreed to participate in our survey. We analyzed a sample of 7706 individuals (5106 men and 2600 women) with 13.2% of men and 8.9% of the women fulfilling the criteria for the MetS. The participants were divided into quintiles of resting heart rate. Multiple adjusted odds ratio was calculated for having the MetS in each quintile compared to the first. Results The multi-adjusted odds for the presence of the MetS increased gradually from an arbitrarily defined figure of 1.0 in the lowest RHR quintile (<60 beats per minute (BPM) in men and <64 BPM in women) to 4.1 and 4.2 in men and women respectively in the highest one (≥80 BPM in men and ≥82 BPM in women). Conclusion Raised resting heart rate is significantly associated with the presence of MetS in a group of apparently healthy individuals and those with an atherothrombotic risk. The strength of this association supports the potential presence of one or more shared pathophysiological mechanisms for both RHR and the MetS. PMID:19828043

  15. Diversity of cultivated and metabolically active aerobic anoxygenic phototrophic bacteria along an oligotrophic gradient in the Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Jeanthon, C.; Boeuf, D.; Dahan, O.; Le Gall, F.; Garczarek, L.; Bendif, E. M.; Lehours, A.-C.

    2011-07-01

    Aerobic anoxygenic phototrophic (AAP) bacteria play significant roles in the bacterioplankton productivity and biogeochemical cycles of the surface ocean. In this study, we applied both cultivation and mRNA-based molecular methods to explore the diversity of AAP bacteria along an oligotrophic gradient in the Mediterranean Sea in early summer 2008. Colony-forming units obtained on three different agar media were screened for the production of bacteriochlorophyll-a (BChl-a), the light-harvesting pigment of AAP bacteria. BChl-a-containing colonies represented a low part of the cultivable fraction. In total, 54 AAP strains were isolated and the phylogenetic analyses based on their 16S rRNA and pufM genes showed that they were all affiliated to the Alphaproteobacteria. The most frequently isolated strains belonged to Citromicrobium bathyomarinum, and Erythrobacter and Roseovarius species. Most other isolates were related to species not reported to produce BChl-a and/or may represent novel taxa. Direct extraction of RNA from seawater samples enabled the analysis of the expression of pufM, the gene coding for the M subunit of the reaction centre complex of aerobic anoxygenic photosynthesis. Clone libraries of pufM gene transcripts revealed that most phylotypes were highly similar to sequences previously recovered from the Mediterranean Sea and a large majority (~94 %) was affiliated to the Gammaproteobacteria. The most abundantly detected phylotypes occurred in the western and eastern Mediterranean basins. However, some were exclusively detected in the eastern basin, reflecting the highest diversity of pufM transcripts observed in this ultra-oligotrophic region. To our knowledge, this is the first study to document extensively the diversity of AAP isolates and to unveil the active AAP community in an oligotrophic marine environment. By pointing out the discrepancies between culture-based and molecular methods, this study highlights the existing gaps in the understanding

  16. Diversity of cultivated and metabolically active aerobic anoxygenic phototrophic bacteria along an oligotrophic gradient in the Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Jeanthon, C.; Boeuf, D.; Dahan, O.; Le Gall, F.; Garczarek, L.; Bendif, E. M.; Lehours, A.-C.

    2011-05-01

    Aerobic anoxygenic phototrophic (AAP) bacteria play significant roles in the bacterioplankton productivity and biogeochemical cycles of the surface ocean. In this study, we applied both cultivation and mRNA-based molecular methods to explore the diversity of AAP bacteria along an oligotrophic gradient in the Mediterranean Sea in early summer 2008. Colony-forming units obtained on three different agar media were screened for the production of bacteriochlorophyll-a (BChl-a), the light-harvesting pigment of AAP bacteria. BChl-a-containing colonies represented a low part of the cultivable fraction. In total, 52 AAP strains were isolated and the phylogenetic analyses based on their 16S rRNA and pufM genes showed that they were all affiliated to the Alphaproteobacteria. The most frequently isolated strains belonged to Citromicrobium bathyomarinum, and Erythrobacter and Roseovarius species. Most other isolates were related to species not reported to produce BChl-a and/or may represent novel taxa. Direct extraction of RNA from seawater samples enabled the analysis of the expression of pufM, the gene coding for the M subunit of the reaction centre complex of aerobic anoxygenic photosynthesis. Clone libraries of pufM gene transcripts revealed that most phylotypes were highly similar to sequences previously recovered from the Mediterranean Sea and a large majority (~94%) was affiliated with the Gammaproteobacteria. The most abundantly detected phylotypes occurred in the western and eastern Mediterranean basins. However, some were exclusively detected in the eastern basin, reflecting the highest diversity of pufM transcripts observed in this ultra-oligotrophic region. To our knowledge, this is the first study to document extensively the diversity of AAP isolates and to unveil the active AAP community in an oligotrophic marine environment. By pointing out the discrepancies between culture-based and molecular methods, this study highlights the existing gaps in the understanding

  17. Comparing the effects of two in-flight aerobic exercise protocols on standing heart rates and VO(2peak) before and after space flight

    NASA Technical Reports Server (NTRS)

    Siconolfi, S. F.; Charles, J. B.; Moore, A. D. Jr; Barrows, L. H.

    1994-01-01

    The effects of regular aerobic exercise on orthostatic tolerance have been the subject of a long-standing controversy that will influence the use of exercise during space flight. To examine these effects, astronauts performed continuous (CE) aerobic exercise (n = 8), interval (IE) aerobic exercise (n = 4), or no (NE) exercise (n = 5) during flights of 7 to 11 days. Heart rate (HR) responses to an orthostatic challenge (stand test) were measured 10 days before flight and on landing day. VO(2peak) (graded treadmill exercise) was measured 7 to 21 days before and 2 days after flight. No significant differences across the groups were observed in standing HRs before or after flight. However, the within-group mean HRs significantly increased in the NE (71-89 beats/min) and CE (60-85 beats/min) groups after space flight. The HRs for the IE group did not significantly increase (75-86 beats/min) after space flight. VO(2peak) decreased (P < .05) in the NE (-9.5%) group, but did not change in the CE (-2.4%) and IE (1%) groups. The relationship (r = 0.237) between the delta HR and delta VO(2peak) was not significant. These preliminary results indicate that: (1) continuous exercise does not affect the orthostatic HR response after space flight; (2) interval exercise may minimize an increase in the postflight orthostatic HR; and (3) both exercise protocols can maintain VO(2peak).

  18. Cellular metabolic rates from primary dermal fibroblast cells isolated from birds of different body masses.

    PubMed

    Jimenez, Ana Gabriela; Williams, Joseph B

    2014-10-01

    The rate of metabolism is the speed at which organisms use energy, an integration of energy transformations within the body; it governs biological processes that influence rates of growth and reproduction. Progress at understanding functional linkages between whole organism metabolic rate and underlying mechanisms that influence its magnitude has been slow despite the central role this issue plays in evolutionary and physiological ecology. Previous studies that have attempted to relate how cellular processes translate into whole-organism physiology have done so over a range of body masses of subjects. However, the data still remains controversial when observing metabolic rates at the cellular level. To bridge the gap between these ideas, we examined cellular metabolic rate of primary dermal fibroblasts isolated from 49 species of birds representing a 32,000-fold range in body masses to test the hypothesis that metabolic rate of cultured cells scales with body size. We used a Seahorse XF-96 Extracellular flux analyzer to measure cellular respiration in fibroblasts. Additionally, we measured fibroblast size and mitochondrial content. We found no significant correlation between cellular metabolic rate, cell size, or mitochondrial content and body mass. Additionally, there was a significant relationship between cellular basal metabolic rate and proton leak in these cells. We conclude that metabolic rate of cells isolated in culture does not scale with body mass, but cellular metabolic rate is correlated to growth rate in birds.

  19. Scaling of standard metabolic rate in estuarine crocodiles Crocodylus porosus.

    PubMed

    Seymour, Roger S; Gienger, C M; Brien, Matthew L; Tracy, Christopher R; Charlie Manolis, S; Webb, Grahame J W; Christian, Keith A

    2013-05-01

    Standard metabolic rate (SMR, ml O2 min(-1)) of captive Crocodylus porosus at 30 °C scales with body mass (kg) according to the equation, SMR = 1.01 M(0.829), in animals ranging in body mass of 3.3 orders of magnitude (0.19-389 kg). The exponent is significantly higher than 0.75, so does not conform to quarter-power scaling theory, but rather is likely an emergent property with no single explanation. SMR at 1 kg body mass is similar to the literature for C. porosus and for alligators. The high exponent is not related to feeding, growth, or obesity of captive animals. The log-transformed data appear slightly curved, mainly because SMR is somewhat low in many of the largest animals (291-389 kg). A 3-parameter model is scarcely different from the linear one, but reveals a declining exponent between 0.862 and 0.798. A non-linear model on arithmetic axes overestimates SMR in 70% of the smallest animals and does not satisfactorily represent the data.

  20. Metabolic rates during rest and activity in differently tracheated spiders (Arachnida, Araneae): Pardosa lugubris (Lycosidae) and Marpissa muscosa (Salticidae).

    PubMed

    Schmitz, Anke

    2004-10-01

    With flow-through respirometry under video tracking, the CO(2) release of adult male and female Pardosa lugubris (wolf spider) and Marpissa muscosa (jumping spider) was measured during rest and activity. Activity metabolism was measured in phases in which the animals were spontaneously active and during forced exercise. Standard metabolic rates (V(CO2)/ t) were 1.43 nmol s(-1) g(-1) in M. muscosa and 1.7-1.8 nmol s(-1) g(-1) in P. lugubris. Egg production caused higher resting rates in females compared with the males in P. lugubris. Maximum mass-specific CO(2) release, the additional amount of CO(2 )released after activity and the factorial aerobic scope were higher in M. muscosa. Additionally, half-time recovery and the lag between end of activity and maximum CO(2) release were lower in the jumping spider. The results are consistent with the hypothesis that the well-developed tracheal system in jumping spiders increases the efficiency of the respiratory system in comparison with wolf spiders, which possess similarly developed lungs but only a simple tracheal system that is restricted to the opisthosoma.

  1. Body Composition and Basal Metabolic Rate in Women with Type 2 Diabetes Mellitus

    PubMed Central

    de Figueiredo Ferreira, Marina; Detrano, Filipe; Coelho, Gabriela Morgado de Oliveira; Barros, Maria Elisa; Serrão Lanzillotti, Regina; Firmino Nogueira Neto, José; Portella, Emilson Souza; Serrão Lanzillotti, Haydée; Soares, Eliane de Abreu

    2014-01-01

    Objective. The aim of this study was to determine which of the seven selected equations used to predict basal metabolic rate most accurately estimated the measured basal metabolic rate. Methods. Twenty-eight adult women with type 2 diabetes mellitus participated in this cross-sectional study. Anthropometric and biochemical variables were measured as well as body composition (by absorptiometry dual X-ray emission) and basal metabolic rate (by indirect calorimetry); basal metabolic rate was also estimated by prediction equations. Results. There was a significant difference between the measured and the estimated basal metabolic rate determined by the FAO/WHO/UNU (Pvalue < 0.021) and Huang et al. (Pvalue ≤ 0.005) equations. Conclusion. The calculations using Owen et al's. equation were the closest to the measured basal metabolic rate. PMID:25436144

  2. Body composition and Basal metabolic rate in women with type 2 diabetes mellitus.

    PubMed

    de Figueiredo Ferreira, Marina; Detrano, Filipe; Coelho, Gabriela Morgado de Oliveira; Barros, Maria Elisa; Serrão Lanzillotti, Regina; Firmino Nogueira Neto, José; Portella, Emilson Souza; Serrão Lanzillotti, Haydée; Soares, Eliane de Abreu

    2014-01-01

    Objective. The aim of this study was to determine which of the seven selected equations used to predict basal metabolic rate most accurately estimated the measured basal metabolic rate. Methods. Twenty-eight adult women with type 2 diabetes mellitus participated in this cross-sectional study. Anthropometric and biochemical variables were measured as well as body composition (by absorptiometry dual X-ray emission) and basal metabolic rate (by indirect calorimetry); basal metabolic rate was also estimated by prediction equations. Results. There was a significant difference between the measured and the estimated basal metabolic rate determined by the FAO/WHO/UNU (P value < 0.021) and Huang et al. (P value ≤ 0.005) equations. Conclusion. The calculations using Owen et al's. equation were the closest to the measured basal metabolic rate.

  3. Does the membrane pacemaker theory of metabolism explain the size dependence of metabolic rate in marine mussels?

    PubMed

    Sukhotin, Alexey; Fokina, Natalia; Ruokolainen, Tatiana; Bock, Christian; Pörtner, Hans-Otto; Lannig, Gisela

    2017-02-02

    According to the Membrane Pacemaker Theory of metabolism (MPT) allometric scaling of metabolic rate in animals is determined by the composition of cellular and mitochondrial membranes that changes with body size in a predictable manner. MPT has been elaborated from interspecific comparisons in mammals. It projects that the degree of unsaturation of membrane phospholipids decreases in larger organisms, thereby lowering ion permeability of the membranes and making cellular and thus whole animal metabolism more efficient. Here we tested the applicability of the MPT to a marine ectotherm, the mussel Mytilus edulis at the intraspecific level. We determined effects of body mass on whole organism, tissue and cellular oxygen consumption rates, on heart rate, metabolic enzyme activities and on the lipid composition of membranes. In line with allometric patterns the organismal functions and processes such as heart rate, whole animal respiration rate and phospholipid contents showed a mass-dependent decline. However, the allometry of tissue and cellular respiration and activity of metabolic enzymes was poor; fatty acid unsaturation of membrane phospholipids of gill tissue was independent of animal size. It is thus conceivable that most of the metabolic allometry observed at the organismal level is determined by systemic functions. These whole organism patterns may be supported by energy savings associated with growing cell size but not by structural changes in membranes. Overall, the set of processes contributing to metabolic allometry in ectotherms may differ from that operative in mammals and birds, with a reduced involvement of the mechanisms proposed by the MPT.

  4. Inbreeding effects on standard metabolic rate investigated at cold, benign and hot temperatures in Drosophila melanogaster.

    PubMed

    Jensen, Palle; Overgaard, Johannes; Loeschcke, Volker; Schou, Mads Fristrup; Malte, Hans; Kristensen, Torsten Nygaard

    2014-03-01

    Inbreeding increases homozygosity, which is known to affect the mean and variance of fitness components such as growth, fecundity and mortality rate. Across inbred lines inbreeding depression is typically observed and the variance between lines is increased in inbred compared to outbred lines. It has been suggested that damage incurred from increased homozygosity entails energetic cost associated with cellular repair. However, little is known about the effects of inbreeding on standard metabolic rate. Using stop-flow respirometry we performed repeated measurements of metabolic rate in replicated lines of inbred and outbred Drosophila melanogaster at stressful low, benign and stressful high temperatures. The lowest measurements of metabolic rate in our study are always associated with the low activity period of the diurnal cycle and these measurements therefore serve as good estimates of standard metabolic rate. Due to the potentially added costs of genetic stress in inbred lines we hypothesized that inbred individuals have increased metabolic rate compared to outbred controls and that this is more pronounced at stressful temperatures due to synergistic inbreeding by environment interactions. Contrary to our hypothesis we found no significant difference in metabolic rate between inbred and outbred lines and no interaction between inbreeding and temperature. Inbreeding however effected the variance; the variance in metabolic rate was higher between the inbred lines compared to the outbred control lines with some inbred lines having very high or low standard metabolic rate. Thus genetic drift and not inbreeding per se seem to explain variation in metabolic rate in populations of different size.

  5. Metabolism correlates with variation in post-natal growth rate among songbirds at three latitudes

    USGS Publications Warehouse

    Ton, Riccardo; Martin, Thomas E.

    2016-01-01

    4. Our results suggest that variation in metabolic rates has an important influence on broad patterns of avian growth rates at a global scale. We suggest further studies that address the ecological and physiological costs and consequences of variation in metabolism and growth rates.

  6. Die aerobe Glykolyse der Tumorzelle

    NASA Astrophysics Data System (ADS)

    Schneider, Friedhelm

    1981-01-01

    A high aerobic glycolysis (aerobic lactate production) is the most significant feature of the energy metabolism of rapidly growing tumor cells. Several mechanisms, which may be different in different cell lines, seem to be involved in this characteristic of energy metabolism of the tumor cell. Changes in the cell membrane leading to increased uptake and utilization of glucose, a high level of fetal types of isoenzymes, a decreased number of mitochondria and a reduced capacity to metabolize pyruvate are some factors which must be taken into consideration. It is not possible to favour one of them at the present time.

  7. Mass-Specific Metabolic Rate Influences Sperm Performance through Energy Production in Mammals.

    PubMed

    Tourmente, Maximiliano; Roldan, Eduardo R S

    2015-01-01

    Mass-specific metabolic rate, the rate at which organisms consume energy per gram of body weight, is negatively associated with body size in metazoans. As a consequence, small species have higher cellular metabolic rates and are able to process resources at a faster rate than large species. Since mass-specific metabolic rate has been shown to constrain evolution of sperm traits, and most of the metabolic activity of sperm cells relates to ATP production for sperm motility, we hypothesized that mass-specific metabolic rate could influence sperm energetic metabolism at the cellular level if sperm cells maintain the metabolic rate of organisms that generate them. We compared data on sperm straight-line velocity, mass-specific metabolic rate, and sperm ATP content from 40 mammalian species and found that the mass-specific metabolic rate positively influences sperm swimming velocity by (a) an indirect effect of sperm as the result of an increased sperm length, and (b) a direct effect independent of sperm length. In addition, our analyses show that species with higher mass-specific metabolic rate have higher ATP content per sperm and higher concentration of ATP per μm of sperm length, which are positively associated with sperm velocity. In conclusion, our results suggest that species with high mass-specific metabolic rate have been able to evolve both long and fast sperm. Moreover, independently of its effect on the production of larger sperm, the mass-specific metabolic rate is able to influence sperm velocity by increasing sperm ATP content in mammals.

  8. Accuracy of predicted resting metabolic rate and relationship between resting metabolic rate and cardiorespiratory fitness in obese men

    PubMed Central

    Kim, Do Kyung

    2014-01-01

    [Purpose] The purpose of this study is to examine that not only the relationship of the resting metabolic rate (RMR) and cardiorespiratory fitness(VO2peak), but also the comparison between measured and predicted results of RMR in obese men. [Methods] 60 obese men (body fat>32%) were recruited for this study. They did not participate in regular exercising programs at least 6 months. The RMR was measured with indirect calorimetry and predicted RMR using Herris-Benedicte equation. The cardiorespiratory fitness was determined by directly measuring the oxygen consumption (VO2peak) during the exercise on the treadmill. [Results] The significance for the difference between the measured results and predicted result of RMR were tested by paired t-test. Correlation of measured date was obtained by Pearson correlation coefficient. The value of predicted RMR and measured RMR were significantly different in these obese subjects. (p < 0.001). The difference between RMR cardiorespiratory fitness and cardiorespiratory fitness showed significant correlation (r=0.67, p < 0.05). [Conclusion] The current formulas of predicted RMR have limited the evaluation of measured RMR for Korean obese men. Therefore, this study suggests that new formula should be designed for Korean in order to obtain more accurate results in obese. PMID:25566436

  9. Estimates of metabolic rate and major constituents of metabolic demand in fishes under field conditions: Methods, proxies, and new perspectives.

    PubMed

    Treberg, Jason R; Killen, Shaun S; MacCormack, Tyson J; Lamarre, Simon G; Enders, Eva C

    2016-12-01

    Metabolic costs are central to individual energy budgets, making estimates of metabolic rate vital to understanding how an organism interacts with its environment as well as the role of species in their ecosystem. Despite the ecological and commercial importance of fishes, there are currently no widely adopted means of measuring field metabolic rate in fishes. The lack of recognized methods is in part due to the logistical difficulties of measuring metabolic rates in free swimming fishes. However, further development and refinement of techniques applicable for field-based studies on free swimming animals would greatly enhance the capacity to study fish under environmentally relevant conditions. In an effort to foster discussion in this area, from field ecologists to biochemists alike, we review aspects of energy metabolism and give details on approaches that have been used to estimate energetic parameters in fishes. In some cases, the techniques have been applied to field conditions; while in others, the methods have been primarily used on laboratory held fishes but should be applicable, with validation, to fishes in their natural environment. Limitations, experimental considerations and caveats of these measurements and the study of metabolism in wild fishes in general are also discussed. Potential novel approaches to FMR estimates are also presented for consideration. The innovation of methods for measuring field metabolic rate in free-ranging wild fish would revolutionize the study of physiological ecology.

  10. Expensive Brains: “Brainy” Rodents have Higher Metabolic Rate

    PubMed Central

    Sobrero, Raúl; May-Collado, Laura J.; Agnarsson, Ingi; Hernández, Cristián E.

    2011-01-01

    Brains are the centers of the nervous system of animals, controlling the organ systems of the body and coordinating responses to changes in the ecological and social environment. The evolution of traits that correlate with cognitive ability, such as relative brain size is thus of broad interest. Brain mass relative to body mass (BM) varies among mammals, and diverse factors have been proposed to explain this variation. A recent study provided evidence that energetics play an important role in brain evolution (Isler and van Schaik, 2006). Using composite phylogenies and data drawn from multiple sources, these authors showed that basal metabolic rate (BMR) correlates with brain mass across mammals. However, no such relationship was found within rodents. Here we re-examined the relationship between BMR and brain mass within Rodentia using a novel species-level phylogeny. Our results are sensitive to parameter evaluation; in particular how species mass is estimated. We detect no pattern when applying an approach used by previous studies, where each species BM is represented by two different numbers, one being the individual that happened to be used for BMR estimates of that species. However, this approach may compromise the analysis. When using a single value of BM for each species, whether representing a single individual, or available species mean, our findings provide evidence that brain mass (independent of BM) and BMR are correlated. These findings are thus consistent with the hypothesis that large brains evolve when the payoff for increased brain mass is greater than the energetic cost they incur. PMID:21811456

  11. Gene expression centroids that link with low intrinsic aerobic exercise capacity and complex disease risk

    PubMed Central

    Kivelä, Riikka; Silvennoinen, Mika; Lehti, Maarit; Rinnankoski-Tuikka,, Rita; Purhonen, Tatja; Ketola, Tarmo; Pullinen, Katri; Vuento, Meri; Mutanen, Niina; Sartor, Maureen A.; Reunanen, Hilkka; Koch, Lauren G.; Britton, Steven L.; Kainulainen, Heikki

    2010-01-01

    A strong link exists between low aerobic exercise capacity and complex metabolic diseases. To probe this linkage, we utilized rat models of low and high intrinsic aerobic endurance running capacity that differ also in the risk for metabolic syndrome. We investigated in skeletal muscle gene-phenotype relationships that connect aerobic endurance capacity with metabolic disease risk factors. The study compared 12 high capacity runners (HCRs) and 12 low capacity runners (LCRs) from generation 18 of selection that differed by 615% for maximal treadmill endurance running capacity. On average, LCRs were heavier and had increased blood glucose, insulin, and triglycerides compared with HCRs. HCRs were higher for resting metabolic rate, voluntary activity, serum high density lipoproteins, muscle capillarity, and mitochondrial area. Bioinformatic analysis of skeletal muscle gene expression data revealed that many genes up-regulated in HCRs were related to oxidative energy metabolism. Seven mean mRNA expression centroids, including oxidative phosphorylation and fatty acid metabolism, correlated significantly with several exercise capacity and disease risk phenotypes. These expression-phenotype correlations, together with diminished skeletal muscle capillarity and mitochondrial area in LCR rats, support the general hypothesis that an inherited intrinsic aerobic capacity can underlie disease risks.—Kivelä, R., Silvennoinen, M., Lehti, M., Rinnankoski-Tuikka, R., Purhonen, T., Ketola, T., Pullinen, K., Vuento, M., Mutanen, N., Sartor, M. A., Reunanen, H., Koch, L. G., Britton, S. L., Kainulainen, H. Gene expression centroids that link with low intrinsic aerobic exercise capacity and complex disease risk. PMID:20643908

  12. Genotype by temperature interactions in the metabolic rate of the Glanville fritillary butterfly.

    PubMed

    Niitepõld, Kristjan

    2010-04-01

    Metabolic rate is a highly plastic trait. Here I examine factors that influence the metabolic rate of the Glanville fritillary butterfly (Melitaea cinxia) in pupae and resting and flying adults. Body mass and temperature had consistent positive effects on metabolic rate in pupae and resting adults but not in flying adults. There was also a consistent nonlinear effect of the time of the day, which was strongest in pupae and weakest in flying adults. Flight metabolic rate was strongly affected by an interaction between the phosphoglucose isomerase (Pgi) genotype and temperature. Over a broad range of measurement temperatures, heterozygous individuals at a single nucleotide polymorphism (SNP) in Pgi had higher peak metabolic rate in flight, but at high temperatures homozygous individuals performed better. The two genotypes did not differ in resting metabolic rate, suggesting that the heterozygotes do not pay an additional energetic cost for their higher flight capacity. Mass-independent resting and flight metabolic rates were at best weakly correlated at the individual level, and therefore, unlike in many vertebrates, resting metabolic rate does not serve as a useful surrogate of the metabolic capacity of this butterfly.

  13. Why mammalian lineages respond differently to sexual selection: metabolic rate constrains the evolution of sperm size.

    PubMed

    Gomendio, Montserrat; Tourmente, Maximiliano; Roldan, Eduardo R S

    2011-10-22

    The hypothesis that sperm competition should favour increases in sperm size, because it results in faster swimming speeds, has received support from studies on many taxa, but remains contentious for mammals. We suggest that this may be because mammalian lineages respond differently to sexual selection, owing to major differences in body size, which are associated with differences in mass-specific metabolic rate. Recent evidence suggests that cellular metabolic rate also scales with body size, so that small mammals have cells that process energy and resources from the environment at a faster rate. We develop the 'metabolic rate constraint hypothesis' which proposes that low mass-specific metabolic rate among large mammals may limit their ability to respond to sexual selection by increasing sperm size, while this constraint does not exist among small mammals. Here we show that among rodents, which have high mass-specific metabolic rates, sperm size increases under sperm competition, reaching the longest sperm sizes found in eutherian mammals. By contrast, mammalian lineages with large body sizes have small sperm, and while metabolic rate (corrected for body size) influences sperm size, sperm competition levels do not. When all eutherian mammals are analysed jointly, our results suggest that as mass-specific metabolic rate increases, so does maximum sperm size. In addition, species with low mass-specific metabolic rates produce uniformly small sperm, while species with high mass-specific metabolic rates produce a wide range of sperm sizes. These findings support the hypothesis that mass-specific metabolic rates determine the budget available for sperm production: at high levels, sperm size increases in response to sexual selection, while low levels constrain the ability to respond to sexual selection by increasing sperm size. Thus, adaptive and costly traits, such as sperm size, may only evolve under sexual selection when metabolic rate does not constrain cellular

  14. Elevational variation in adult body size and growth rate but not in metabolic rate in the tree weta Hemideina crassidens.

    PubMed

    Bulgarella, Mariana; Trewick, Steven A; Godfrey, A Jonathan R; Sinclair, Brent J; Morgan-Richards, Mary

    2015-04-01

    Populations of the same species inhabiting distinct localities experience different ecological and climatic pressures that might result in differentiation in traits, particularly those related to temperature. We compared metabolic rate (and its thermal sensitivity), growth rate, and body size among nine high- and low-elevation populations of the Wellington tree weta, Hemideina crassidens, distributed from 9 to 1171 m a.s.l across New Zealand. Our results did not indicate elevational compensation in metabolic rates (metabolic cold adaptation). Cold acclimation decreased metabolic rate compared to warm-acclimated individuals from both high- and low-elevation populations. However, we did find countergradient variation in growth rates, with individuals from high-elevation populations growing faster and to a larger final size than individuals from low-elevation populations. Females grew faster to a larger size than males, although as adults their metabolic rates did not differ significantly. The combined physiological and morphological data suggest that high-elevation individuals grow quickly and achieve larger size while maintaining metabolic rates at levels not significantly different from low-elevation individuals. Thus, morphological differentiation among tree weta populations, in concert with genetic variation, might provide the material required for adaptation to changing conditions.

  15. Warming reduces metabolic rate in marine snails: adaptation to fluctuating high temperatures challenges the metabolic theory of ecology.

    PubMed

    Marshall, David J; McQuaid, Christopher D

    2011-01-22

    The universal temperature-dependence model (UTD) of the metabolic theory of ecology (MTE) proposes that temperature controls mass-scaled, whole-animal resting metabolic rate according to the first principles of physics (Boltzmann kinetics). Controversy surrounds the model's implication of a mechanistic basis for metabolism that excludes the effects of adaptive regulation, and it is unclear how this would apply to organisms that live in fringe environments and typically show considerable metabolic adaptation. We explored thermal scaling of metabolism in a rocky-shore eulittoral-fringe snail (Echinolittorina malaccana) that experiences constrained energy gain and fluctuating high temperatures (between 25°C and approximately 50°C) during prolonged emersion (weeks). In contrast to the prediction of the UTD model, metabolic rate was often negatively related to temperature over a benign range (30-40°C), the relationship depending on (i) the temperature range, (ii) the degree of metabolic depression (related to the quiescent period), and (iii) whether snails were isolated within their shells. Apparent activation energies (E) varied between 0.05 and -0.43 eV, deviating excessively from the UTD's predicted range of between 0.6 and 0.7 eV. The lowering of metabolism when heated should improve energy conservation in a high-temperature environment and challenges both the theory's generality and its mechanistic basis.

  16. Warming reduces metabolic rate in marine snails: adaptation to fluctuating high temperatures challenges the metabolic theory of ecology

    PubMed Central

    Marshall, David J.; McQuaid, Christopher D.

    2011-01-01

    The universal temperature-dependence model (UTD) of the metabolic theory of ecology (MTE) proposes that temperature controls mass-scaled, whole-animal resting metabolic rate according to the first principles of physics (Boltzmann kinetics). Controversy surrounds the model's implication of a mechanistic basis for metabolism that excludes the effects of adaptive regulation, and it is unclear how this would apply to organisms that live in fringe environments and typically show considerable metabolic adaptation. We explored thermal scaling of metabolism in a rocky-shore eulittoral-fringe snail (Echinolittorina malaccana) that experiences constrained energy gain and fluctuating high temperatures (between 25°C and approximately 50°C) during prolonged emersion (weeks). In contrast to the prediction of the UTD model, metabolic rate was often negatively related to temperature over a benign range (30–40°C), the relationship depending on (i) the temperature range, (ii) the degree of metabolic depression (related to the quiescent period), and (iii) whether snails were isolated within their shells. Apparent activation energies (E) varied between 0.05 and −0.43 eV, deviating excessively from the UTD's predicted range of between 0.6 and 0.7 eV. The lowering of metabolism when heated should improve energy conservation in a high-temperature environment and challenges both the theory's generality and its mechanistic basis. PMID:20685714

  17. Metabolism

    MedlinePlus

    ... and intestines. Several of the hormones of the endocrine system are involved in controlling the rate and direction ... For Kids For Parents MORE ON THIS TOPIC Endocrine System What Can I Do About My High Metabolism? ...

  18. Acclimatization of seasonal energetics in northern cardinals (Cardinalis cardinalis) through plasticity of metabolic rates and ceilings.

    PubMed

    Sgueo, Carrie; Wells, Marion E; Russell, David E; Schaeffer, Paul J

    2012-07-15

    Northern cardinals (Cardinalis cardinalis) are faced with energetically expensive seasonal challenges that must be met to ensure survival, including thermoregulation in winter and reproductive activities in summer. Contrary to predictions of life history theory that suggest breeding metabolic rate should be the apex of energetic effort, winter metabolism exceeds that during breeding in several temperate resident bird species. By examining whole-animal, tissue and cellular function, we ask whether seasonal acclimatization is accomplished by coordinated phenotypic plasticity of metabolic systems. We measured summit metabolism (V(O(2),sum)), daily energy expenditure (DEE) and muscle oxidative capacity under both winter (December to January) and breeding (May to June) conditions. We hypothesize that: (1) rates of energy utilization will be highest in the winter, contrary to predictions based on life history theory, and (2) acclimatization of metabolism will occur at multiple levels of organization such that birds operate with a similar metabolic ceiling during different seasons. We measured field metabolic rates using heart rate telemetry and report the first daily patterns in avian field metabolic rate. Patterns of daily energy use differed seasonally, primarily as birds maintain high metabolic rates throughout the winter daylight hours. We found that DEE and V(O(2),sum) were significantly greater and DEE occurred at a higher fraction of maximum metabolic capacity during winter, indicating an elevation of the metabolic ceiling. Surprisingly, there were no significant differences in mass or oxidative capacity of skeletal muscle. These data, highlighting the importance of examining energetic responses to seasonal challenges at multiple levels, clearly reject life history predictions that breeding is the primary energetic challenge for temperate zone residents. Further, they indicate that metabolic ceilings are seasonally flexible as metabolic effort during winter

  19. Thyroid hormones correlate with resting metabolic rate, not daily energy expenditure, in two charadriiform seabirds.

    PubMed

    Elliott, Kyle H; Welcker, Jorg; Gaston, Anthony J; Hatch, Scott A; Palace, Vince; Hare, James F; Speakman, John R; Anderson, W Gary

    2013-06-15

    Thyroid hormones affect in vitro metabolic intensity, increase basal metabolic rate (BMR) in the lab, and are sometimes correlated with basal and/or resting metabolic rate (RMR) in a field environment. Given the difficulty of measuring metabolic rate in the field-and the likelihood that capture and long-term restraint necessary to measure metabolic rate in the field jeopardizes other measurements-we examined the possibility that circulating thyroid hormone levels were correlated with RMR in two free-ranging bird species with high levels of energy expenditure (the black-legged kittiwake, Rissa tridactyla, and thick-billed murre, Uria lomvia). Because BMR and daily energy expenditure (DEE) are purported to be linked, we also tested for a correlation between thyroid hormones and DEE. We examined the relationships between free and bound levels of the thyroid hormones thyroxine (T4) and triiodothyronine (T3) with DEE and with 4-hour long measurements of post-absorptive and thermoneutral resting metabolism (resting metabolic rate; RMR). RMR but not DEE increased with T3 in both species; both metabolic rates were independent of T4. T3 and T4 were not correlated with one another. DEE correlated with body mass in kittiwakes but not in murres, presumably owing to the larger coefficient of variation in body mass during chick rearing for the more sexually dimorphic kittiwakes. We suggest T3 provides a good proxy for resting metabolism but not DEE in these seabird species.

  20. Impact of a Metabolic Screening Bundle on Rates of Screening for Metabolic Syndrome in a Psychiatry Resident Outpatient Clinic

    ERIC Educational Resources Information Center

    Wiechers, Ilse R.; Viron, Mark; Stoklosa, Joseph; Freudenreich, Oliver; Henderson, David C.; Weiss, Anthony

    2012-01-01

    Objective: Although it is widely acknowledged that second-generation antipsychotics are associated with cardiometabolic side effects, rates of metabolic screening have remained low. The authors created a quality-improvement (QI) intervention in an academic medical center outpatient psychiatry resident clinic with the aim of improving rates of…

  1. Glutathione-mediated antioxidant response and aerobic metabolism: two crucial factors involved in determining the multi-drug resistance of high-risk neuroblastoma

    PubMed Central

    Colla, Renata; Izzotti, Alberto; De Ciucis, Chiara; Fenoglio, Daniela; Ravera, Silvia; Speciale, Andrea; Ricciarelli, Roberta; Furfaro, Anna Lisa; Pulliero, Alessandra; Passalacqua, Mario; Traverso, Nicola; Pronzato, Maria Adelaide; Domenicotti, Cinzia; Marengo, Barbara

    2016-01-01

    Neuroblastoma, a paediatric malignant tumor, is initially sensitive to etoposide, a drug to which many patients develop chemoresistance. In order to investigate the molecular mechanisms responsible for etoposide chemoresistance, HTLA-230, a human MYCN-amplified neuroblastoma cell line, was chronically treated with etoposide at a concentration that in vitro mimics the clinically-used dose. The selected cells (HTLA-Chr) acquire multi-drug resistance (MDR), becoming less sensitive than parental cells to high doses of etoposide or doxorubicin. MDR is due to several mechanisms that together contribute to maintaining non-toxic levels of H2O2. In fact, HTLA-Chr cells, while having an efficient aerobic metabolism, are also characterized by an up-regulation of catalase activity and higher levels of reduced glutathione (GSH), a thiol antioxidant compound. The combination of such mechanisms contributes to prevent membrane lipoperoxidation and cell death. Treatment of HTLA-Chr cells with L-Buthionine-sulfoximine, an inhibitor of GSH biosynthesis, markedly reduces their tumorigenic potential that is instead enhanced by the exposure to N-Acetylcysteine, able to promote GSH synthesis. Collectively, these results demonstrate that GSH and GSH-related responses play a crucial role in the acquisition of MDR and suggest that GSH level monitoring is an efficient strategy to early identify the onset of drug resistance and to control the patient's response to therapy. PMID:27683112

  2. 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.

  3. Aerobic Anoxygenic Phototrophic Bacteria

    PubMed Central

    Yurkov, Vladimir V.; Beatty, J. Thomas

    1998-01-01

    The aerobic anoxygenic phototrophic bacteria are a relatively recently discovered bacterial group. Although taxonomically and phylogenetically heterogeneous, these bacteria share the following distinguishing features: the presence of bacteriochlorophyll a incorporated into reaction center and light-harvesting complexes, low levels of the photosynthetic unit in cells, an abundance of carotenoids, a strong inhibition by light of bacteriochlorophyll synthesis, and the inability to grow photosynthetically under anaerobic conditions. Aerobic anoxygenic phototrophic bacteria are classified in two marine (Erythrobacter and Roseobacter) and six freshwater (Acidiphilium, Erythromicrobium, Erythromonas, Porphyrobacter, Roseococcus, and Sandaracinobacter) genera, which phylogenetically belong to the α-1, α-3, and α-4 subclasses of the class Proteobacteria. Despite this phylogenetic information, the evolution and ancestry of their photosynthetic properties are unclear. We discuss several current proposals for the evolutionary origin of aerobic phototrophic bacteria. The closest phylogenetic relatives of aerobic phototrophic bacteria include facultatively anaerobic purple nonsulfur phototrophic bacteria. Since these two bacterial groups share many properties, yet have significant differences, we compare and contrast their physiology, with an emphasis on morphology and photosynthetic and other metabolic processes. PMID:9729607

  4. Estimating resting metabolic rate by biologging core and subcutaneous temperature in a mammal.

    PubMed

    Rey, Benjamin; Halsey, Lewis G; Hetem, Robyn S; Fuller, Andrea; Mitchell, Duncan; Rouanet, Jean-Louis

    2015-05-01

    Tri-axial accelerometry has been used to continuously and remotely assess field metabolic rates in free-living endotherms. However, in cold environments, the use of accelerometry may underestimate resting metabolic rate because cold-induced stimulation of metabolic rate causes no measurable acceleration. To overcome this problem, we investigated if logging the difference between core and subcutaneous temperatures (ΔTc-s) could reveal the metabolic costs associated with cold exposure. Using implanted temperature data loggers, we recorded core and subcutaneous temperatures continuously in eight captive rabbits (Oryctolagus cuniculus) and concurrently measured their resting metabolic rate by indirect calorimetry, at ambient temperatures ranging from -7 to +25°C. ΔTc-s showed no circadian fluctuations in warm (+23°C) or cold (+5°C) environments implying that the ΔTc-s was not affected by an endogenous circadian rhythm in our laboratory conditions. ΔTc-s correlated well with resting metabolic rate (R(2)=0.77) across all ambient temperatures except above the upper limit of the thermoneutral zone (+25°C). Determining ΔTc-s could therefore provide a complementary approach for better estimating resting metabolic rate of animals within and below their thermoneutral zone. Combining data from accelerometers with such measures of body temperature could improve estimates of the overall field metabolic rate of free-living endotherms.

  5. Effects of aerobic exercise training on metabolism of nitric oxide and endothelin-1 in lung parenchyma of rats with pulmonary arterial hypertension.

    PubMed

    Zimmer, A; Teixeira, R B; Bonetto, J H P; Siqueira, R; Carraro, C C; Donatti, L M; Hickmann, A; Litvin, I E; Godoy, A E G; Araujo, A S; Colombo, R; Belló-Klein, Adriane

    2017-05-01

    Pulmonary arterial hypertension (PAH) is characterized by vasoconstriction and proliferative obstruction of pulmonary vessels, which promotes a progressive increase in pulmonary vascular resistance (PVR). The effect of exercise training on oxidative stress, metabolism, and markers of nitric oxide (NO) and endothelin-1 (ET-1) was analyzed in the lung tissue of rats with PAH induced by monocrotaline (MCT).Twenty-four Wistar rats were divided into four groups (5-7 animals): sedentary control (SC), sedentary MCT (SM), trained control (TC), and trained MCT (TM). The TC and TM groups participated in a treadmill training protocol (60% VO2 max) for 5 weeks, 3 weeks of which were performed after the injection of MCT (60 mg/kg i.p.) or saline. MCT administration promoted an increase in PVR and right ventricle hypertrophy, and reduction of right ventricle systolic function assessed by echocardiography. These changes were not improved by exercise training. The activity of NO synthase was reduced in the animals of the TC, TM, and SM groups. No significant differences were found in total nitrite concentration and expression of endothelial NO synthase. Moreover, the TM group showed strong staining for iNOS and nitrotyrosine, suggesting an increase in oxidative stress in these animals. In parallel, reduced expression of type B ET-1 receptors was noticed in the SM and TM groups in comparison to controls. In conclusion, the aerobic training protocol was unable to mitigate changes in the metabolism of NO and ET-1, probably because of the disease severity in these animals, especially in the TM group.

  6. Saccharomyces cerevisiae engineered for xylose metabolism requires gluconeogenesis and the oxidative branch of the pentose phosphate pathway for aerobic xylose assimilation.

    PubMed

    Hector, Ronald E; Mertens, Jeffrey A; Bowman, Michael J; Nichols, Nancy N; Cotta, Michael A; Hughes, Stephen R

    2011-09-01

    Saccharomyces strains engineered to ferment xylose using Scheffersomyces stipitis xylose reductase (XR) and xylitol dehydrogenase (XDH) genes appear to be limited by metabolic imbalances, due to differing cofactor specificities of XR and XDH. The S. stipitis XR, which uses both NADH and NADPH, is hypothesized to reduce the cofactor imbalance, allowing xylose fermentation in this yeast. However, unadapted S. cerevisiae strains expressing this XR grow poorly on xylose, suggesting that metabolism is still imbalanced, even under aerobic conditions. In this study, we investigated the possible reasons for this imbalance by deleting genes required for NADPH production and gluconeogenesis in S. cerevisiae. S. cerevisiae cells expressing the XR-XDH, but not a xylose isomerase, pathway required the oxidative branch of the pentose phosphate pathway (PPP) and gluconeogenic production of glucose-6-P for xylose assimilation. The requirement for generating glucose-6-P from xylose was also shown for Kluyveromyces lactis. When grown in xylose medium, both K. lactis and S. stipitis showed increases in enzyme activity required for producing glucose-6-P. Thus, natural xylose-assimilating yeast respond to xylose, in part, by upregulating enzymes required for recycling xylose back to glucose-6-P for the production of NADPH via the oxidative branch of the PPP. Finally, we show that induction of these enzymes correlated with increased tolerance to the NADPH-depleting compound diamide and the fermentation inhibitors furfural and hydroxymethyl furfural; S. cerevisiae was not able to increase enzyme activity for glucose-6-P production when grown in xylose medium and was more sensitive to these inhibitors in xylose medium compared to glucose.

  7. Epilepsy, cerebral blood flow, and cerebral metabolic rate.

    PubMed

    Duncan, R

    1992-01-01

    Penfield's observations in the 1930s provided the first systematic evidence of changes in regional cerebral blood flow (rCBF) associated with focal seizures. Further studies in humans and animals confirmed increases in cerebral blood flow and metabolism during generalised seizures, but the interictal, ictal, and postictal changes in focal epilepsy have begun to be elucidated in the last decade with the advent of in vivo imaging techniques such as positron emission tomography (PET) and single photon emission computed tomography (SPECT) and, in the case of animal studies, of autoradiography. Most studies have been of temporal lobe epilepsy. Interictally, the characteristic finding has been reduced blood flow and/or metabolism in the affected temporal lobe, or more extensively in the ipsilateral hemisphere. The few studies to date of ictal or postictal changes have been of rCBF using SPECT. They show hyperperfusion of the whole temporal lobe ictally, hyperperfusion of the hippocampus, combined with hypoperfusion of lateral structures in the immediate postictal period. Later in the postictal period, hypoperfusion alone is seen. Studies of focal seizures in animals have shown hyperperfusion and hypermetabolism at the site of the focus often with widespread depression of both parameters in the ipsilateral neocortex. Limited studies of coupling between blood flow and metabolism in humans have suggested that flow during seizures is adequate for metabolic demand, although some animal studies have suggested localised areas of uncoupling. The results of modern in vivo imaging of ictal and postictal changes in blood flow and metabolism have correlated well with Penfield's observations, and these changes are now being used to help localise epileptic foci, allowing wider use of the surgical treatment he pioneered.

  8. Aerobic Tennis.

    ERIC Educational Resources Information Center

    Stewart, Michael J.; Ahlschwede, Robert

    1989-01-01

    Increasing the aerobic nature of tennis drills in the physical education class may be necessary if tennis is to remain a part of the public school curriculum. This article gives two examples of drills that can be modified by teachers to increase activity level. (IAH)

  9. Effects of organic loading rates on reactor performance and microbial community changes during thermophilic aerobic digestion process of high-strength food wastewater.

    PubMed

    Jang, Hyun Min; Lee, Jae Won; Ha, Jeong Hyub; Park, Jong Moon

    2013-11-01

    To evaluate the applicability of single-stage thermophilic aerobic digestion (TAD) process treating high-strength food wastewater (FWW), TAD process was operated at four organic loading rates (OLRs) from 9.2 to 37.2 kg COD/m(3)d. The effects of OLRs on microbial community changes were also examined. The highest volumetric removal rate (13.3 kg COD/m(3)d) and the highest thermo-stable protease activity (0.95 unit/mL) were detected at OLR=18.6 kg COD/m(3)d. Denaturing gradient gel electrophoresis (DGGE) profiles and quantitative PCR (qPCR) results showed significant microbial community shifts in response to changes in OLR. In particular, DGGE and phylogenetic analysis demonstrate that the presence of Bacillus sp. (phylum of Firmicutes) was strongly correlated with efficient removal of organic particulates from high-strength food wastewater.

  10. Prediction of microbial growth rate versus biomass yield by a metabolic network with kinetic parameters.

    PubMed

    Adadi, Roi; Volkmer, Benjamin; Milo, Ron; Heinemann, Matthias; Shlomi, Tomer

    2012-01-01

    Identifying the factors that determine microbial growth rate under various environmental and genetic conditions is a major challenge of systems biology. While current genome-scale metabolic modeling approaches enable us to successfully predict a variety of metabolic phenotypes, including maximal biomass yield, the prediction of actual growth rate is a long standing goal. This gap stems from strictly relying on data regarding reaction stoichiometry and directionality, without accounting for enzyme kinetic considerations. Here we present a novel metabolic network-based approach, MetabOlic Modeling with ENzyme kineTics (MOMENT), which predicts metabolic flux rate and growth rate by utilizing prior data on enzyme turnover rates and enzyme molecular weights, without requiring measurements of nutrient uptake rates. The method is based on an identified design principle of metabolism in which enzymes catalyzing high flux reactions across different media tend to be more efficient in terms of having higher turnover numbers. Extending upon previous attempts to utilize kinetic data in genome-scale metabolic modeling, our approach takes into account the requirement for specific enzyme concentrations for catalyzing predicted metabolic flux rates, considering isozymes, protein complexes, and multi-functional enzymes. MOMENT is shown to significantly improve the prediction accuracy of various metabolic phenotypes in E. coli, including intracellular flux rates and changes in gene expression levels under different growth rates. Most importantly, MOMENT is shown to predict growth rates of E. coli under a diverse set of media that are correlated with experimental measurements, markedly improving upon existing state-of-the art stoichiometric modeling approaches. These results support the view that a physiological bound on cellular enzyme concentrations is a key factor that determines microbial growth rate.

  11. Ontogeny of Metabolic Rate and Red Blood Cell Size in Eyelid Geckos: Species Follow Different Paths

    PubMed Central

    Starostová, Zuzana; Konarzewski, Marek; Kozłowski, Jan; Kratochvíl, Lukáš

    2013-01-01

    While metabolism is a fundamental feature of all organisms, the causes of its scaling with body mass are not yet fully explained. Nevertheless, observations of negative correlations between red blood cell (RBC) size and the rate of metabolism suggest that size variation of these cells responsible for oxygen supply may play a crucial role in determining metabolic rate scaling in vertebrates. Based on a prediction derived from the Cell Metabolism Hypothesis, metabolic rate should increase linearly with body mass in species with RBC size invariance, and slower than linearly when RBC size increases with body mass. We found support for that prediction in five species of eyelid geckos (family Eublepharidae) with different patterns of RBC size variation during ontogenetic growth. During ontogeny, metabolic rate increases nearly linearly with body mass in those species of eyelid geckos where there is no correlation between RBC size and body mass, whereas non-linearity of metabolic rate scaling is evident in those species with ontogenetic increase of RBC size. Our findings provide evidence that ontogenetic variability in RBC size, possibly correlating with sizes of other cell types, could have important physiological consequences and can contribute to qualitatively different shape of the intraspecific relationship between metabolic rate and body mass. PMID:23705003

  12. Personalized Prediction of Proliferation Rates and Metabolic Liabilities in Cancer Biopsies.

    PubMed

    Diener, Christian; Resendis-Antonio, Osbaldo

    2016-01-01

    Cancer is a heterogeneous disease and its genetic and metabolic mechanism may manifest differently in each patient. This creates a demand for studies that can characterize phenotypic traits of cancer on a per-sample basis. Combining two large data sets, the NCI60 cancer cell line panel, and The Cancer Genome Atlas, we used a linear interaction model to predict proliferation rates for more than 12,000 cancer samples across 33 different cancers from The Cancer Genome Atlas. The predicted proliferation rates are associated with patient survival and cancer stage and show a strong heterogeneity in proliferative capacity within and across different cancer panels. We also show how the obtained proliferation rates can be incorporated into genome-scale metabolic reconstructions to obtain the metabolic fluxes for more than 3000 cancer samples that identified specific metabolic liabilities for nine cancer panels. Here we found that affected pathways coincided with the literature, with pentose phosphate pathway, retinol, and branched-chain amino acid metabolism being the most panel-specific alterations and fatty acid metabolism and ROS detoxification showing homogeneous metabolic activities across all cancer panels. The presented strategy has potential applications in personalized medicine since it can leverage gene expression signatures for cell line based prediction of additional metabolic properties which might help in constraining personalized metabolic models and improve the identification of metabolic alterations in cancer for individual patients.

  13. Personalized Prediction of Proliferation Rates and Metabolic Liabilities in Cancer Biopsies

    PubMed Central

    Diener, Christian; Resendis-Antonio, Osbaldo

    2016-01-01

    Cancer is a heterogeneous disease and its genetic and metabolic mechanism may manifest differently in each patient. This creates a demand for studies that can characterize phenotypic traits of cancer on a per-sample basis. Combining two large data sets, the NCI60 cancer cell line panel, and The Cancer Genome Atlas, we used a linear interaction model to predict proliferation rates for more than 12,000 cancer samples across 33 different cancers from The Cancer Genome Atlas. The predicted proliferation rates are associated with patient survival and cancer stage and show a strong heterogeneity in proliferative capacity within and across different cancer panels. We also show how the obtained proliferation rates can be incorporated into genome-scale metabolic reconstructions to obtain the metabolic fluxes for more than 3000 cancer samples that identified specific metabolic liabilities for nine cancer panels. Here we found that affected pathways coincided with the literature, with pentose phosphate pathway, retinol, and branched-chain amino acid metabolism being the most panel-specific alterations and fatty acid metabolism and ROS detoxification showing homogeneous metabolic activities across all cancer panels. The presented strategy has potential applications in personalized medicine since it can leverage gene expression signatures for cell line based prediction of additional metabolic properties which might help in constraining personalized metabolic models and improve the identification of metabolic alterations in cancer for individual patients. PMID:28082911

  14. Lake Metabolism: Comparison of Lake Metabolic Rates Estimated from a Diel CO2- and the Common Diel O2-Technique

    PubMed Central

    Peeters, Frank; Atamanchuk, Dariia; Tengberg, Anders; Encinas-Fernández, Jorge; Hofmann, Hilmar

    2016-01-01

    Lake metabolism is a key factor for the understanding of turnover of energy and of organic and inorganic matter in lake ecosystems. Long-term time series on metabolic rates are commonly estimated from diel changes in dissolved oxygen. Here we present long-term data on metabolic rates based on diel changes in total dissolved inorganic carbon (DIC) utilizing an open-water diel CO2-technique. Metabolic rates estimated with this technique and the traditional diel O2-technique agree well in alkaline Lake Illmensee (pH of ~8.5), although the diel changes in molar CO2 concentrations are much smaller than those of the molar O2 concentrations. The open-water diel CO2- and diel O2-techniques provide independent measures of lake metabolic rates that differ in their sensitivity to transport processes. Hence, the combination of both techniques can help to constrain uncertainties arising from assumptions on vertical fluxes due to gas exchange and turbulent diffusion. This is particularly important for estimates of lake respiration rates because these are much more sensitive to assumptions on gradients in vertical fluxes of O2 or DIC than estimates of lake gross primary production. Our data suggest that it can be advantageous to estimate respiration rates assuming negligible gradients in vertical fluxes rather than including gas exchange with the atmosphere but neglecting vertical mixing in the water column. During two months in summer the average lake net production was close to zero suggesting at most slightly autotrophic conditions. However, the lake emitted O2 and CO2 during the entire time period suggesting that O2 and CO2 emissions from lakes can be decoupled from the metabolism in the near surface layer. PMID:28002477

  15. Metabolically-Derived Human Ventilation Rates: A Revised Approach Based Upon Oxygen Consumption Rates (External Review Draft)

    EPA Science Inventory

    EPA has released a draft report entitled, Metabolically-Derived Human Ventilation Rates: A Revised Approach Based Upon Oxygen Consumption Rates, for independent external peer review and public comment. NCEA published the Exposure Factors Handbook in 1997. This comprehens...

  16. Mass-Specific Metabolic Rate and Sperm Competition Determine Sperm Size in Marsupial Mammals

    PubMed Central

    Tourmente, Maximiliano; Gomendio, Montserrat; Roldan, Eduardo R. S.

    2011-01-01

    Two complementary hypotheses have been proposed to explain variation in sperm size. The first proposes that post-copulatory sexual selection favors an increase in sperm size because it enhances sperm swimming speed, which is an important determinant of fertilization success in competitive contexts. The second hypothesis proposes that mass-specific metabolic rate acts as a constraint, because large animals with low mass-specific metabolic rates will not be able to process resources at the rates needed to produce large sperm. This constraint is expected to be particularly pronounced among mammals, given that this group contains some of the largest species on Earth. We tested these hypotheses among marsupials, a group in which mass-specific metabolic rates are roughly 30% lower than those of eutherian mammals of similar size, leading to the expectation that metabolic rate should be a major constraint. Our findings support both hypotheses because levels of sperm competition are associated with increases in sperm size, but low mass-specific metabolic rate constrains sperm size among large species. We also found that the relationship between sperm size and mass-specific metabolic rate is steeper among marsupials and shallower among eutherian mammals. This finding has two implications: marsupials respond to changes in mass-specific metabolic rate by modifying sperm length to a greater extent, suggesting that they are more constrained by metabolic rate. In addition, for any given mass-specific metabolic rate, marsupials produce longer sperm. We suggest that this is the consequence of marsupials diverting resources away from sperm numbers and into sperm size, due to their efficient sperm transport along the female tract and the existence of mechanisms to protect sperm. PMID:21731682

  17. Hippocampal structure, metabolism, and inflammatory response after a 6-week intense aerobic exercise in healthy young adults: a controlled trial.

    PubMed

    Wagner, Gerd; Herbsleb, Marco; de la Cruz, Feliberto; Schumann, Andy; Brünner, Franziska; Schachtzabel, Claudia; Gussew, Alexander; Puta, Christian; Smesny, Stefan; Gabriel, Holger W; Reichenbach, Jürgen R; Bär, Karl-Jürgen

    2015-10-01

    Interventional studies suggest that changes in physical fitness affect brain function and structure. We studied the influence of high intensity physical exercise on hippocampal volume and metabolism in 17 young healthy male adults during a 6-week exercise program compared with matched controls. We further aimed to relate these changes to hypothesized changes in exercised-induced brain-derived neurotrophic factor (BDNF), interleukin-6 (IL-6), and tumor necrosis factor alpha (TNF-α). We show profound improvement of physical fitness in most subjects and a positive correlation between the degree of fitness improvement and increased BDNF levels. We unexpectedly observed an average volume decrease of about 2%, which was restricted to right hippocampal subfields CA2/3, subiculum, and dentate gyrus and which correlated with fitness improvement and increased BDNF levels negatively. This result indicates that mainly those subjects who did not benefit from the exercise program show decreased hippocampal volume, reduced BDNF levels, and increased TNF-α concentrations. While spectroscopy results do not indicate any neuronal loss (unchanged N-acetylaspartate levels) decreased glutamate-glutamine levels were observed in the right anterior hippocampus in the exercise group only. Responder characteristics need to be studied in more detail. Our results point to an important role of the inflammatory response after exercise on changes in hippocampal structure.

  18. Lack of Seasonal Differences in Basal Metabolic Rate in Humans: A Cross-Sectional Study.

    PubMed

    Anthanont, Pimjai; Levine, James A; McCrady-Spitzer, Shelly K; Jensen, Michael D

    2017-01-01

    Some studies indicate that basal metabolic rate is greater in winter than in the summer, suggesting a role for brown fat in human thermogenesis. We examined whether there are clinically meaningful differences in basal metabolic rate under thermoneutral conditions between winter and summer months in inhabitants of Rochester, Minnesota. We collated data from 220 research volunteers studied in the winter (December 1 - February 28) and 214 volunteers studied in the summer (June 1 - August 31), 1995-2012. Basal metabolic rate was measured by indirect calorimetry and body composition by dual-energy X-ray absorptiometry. The effect of season on basal metabolic rate was tested using multivariate regression analysis with basal metabolic rate as the dependent variable and fat-free mass, fat mass, age, sex, and season as the independent variables. The groups were comparable with respect to age, body mass index, fat mass, and fat-free mass. There was no significant difference in basal metabolic rate between winter and summer groups (1 667±322 vs. 1 669±330 kcal/day). Both winter and summer basal metabolic rates were strongly predicted by fat-free mass (Pearson's r=0.75 and r=0.77, respectively, p <0.0001). Using multiple linear regression analysis, basal metabolic rate was significantly, independently predicted by fat-free mass, fat mass, age, and sex, but not season. We conclude that the lack of seasonal variation of thermoneutral basal metabolic rate between winter and summer suggests that modern, Western populations do not engage thermogenically detectable brown fat activity during periods of living in a cold climate.

  19. Effect of heart rate on the risk of developing metabolic syndrome.

    PubMed

    Inoue, Taku; Iseki, Kunitoshi; Iseki, Chiho; Ohya, Yusuke; Kinjo, Kozen; Takishita, Shuichi

    2009-09-01

    High heart rate and metabolic syndrome are risk factors for cardiovascular morbidity and mortality. The relationship between heart rate and risk of developing metabolic syndrome has not been studied in a large cohort. We examined the relationship between heart rate and the risk of developing metabolic syndrome in individuals who participated in a health evaluation program from 1997 to 2002. Among the 7958 individuals who participated in the program, 1677 were excluded from our study because they were being treated for heart disease or had been diagnosed with metabolic syndrome at baseline examination. A total of 6281 individuals (3789 men and 2492 women, 20-89 years of age) were evaluated. They were categorized according to their baseline heart rate and were followed up for a mean of 47+/-16 months (range: 7-71 months). Over the 5-year period, 619 individuals (9.9%) developed metabolic syndrome. Men with elevated baseline heart rates were more likely to experience metabolic syndrome than were those with normal heart rates. This was not true for female patients. The odds ratio (95% confidence interval) of developing metabolic syndrome among men in the highest quartile for heart rate was 1.725 (1.282-2.320) compared with those in the lowest quartile. Each increase in the heart rate category led to an approximately 1.2-fold increase in the risk of developing metabolic syndrome for men only, even after adjusting for age and lifestyle. Elevated heart rate is a risk factor for developing metabolic syndrome in men.

  20. Individual inconsistencies in basal and summit metabolic rate highlight flexibility of metabolic performance in a wintering passerine.

    PubMed

    Cortés, Pablo Andrés; Petit, Magali; Lewden, Agnès; Milbergue, Myriam; Vézina, François

    2015-03-01

    Resident passerines inhabiting high latitude environments are faced with strong seasonal changes in thermal conditions and energy availability. Summit metabolic rate (maximal metabolic rate elicited by shivering during cold exposure: M(sum)) and basal metabolic rate (BMR) vary in parallel among seasons and increase in winter due to cold acclimatization, and these adjustments are thought to be critical for survival. Wintering individuals expressing consistently higher M(sum) and BMR could therefore be seen as better performers with higher chances of winter survival than those exhibiting lower metabolic performance. In this study, we calculated repeatability to evaluate temporal consistency of body mass, BMR and M(sum) within and across three consecutives winters in black-capped chickadees (Poecile atricapillus). We found that body mass was significantly repeatable both within and across winters (R 0.51-0.90). BMR (R 0.29-0.47) was only repeatable within winter while M(sum) was repeatable both among (R 0.33-0.49) and within winters (R 0.33-0.49) with the magnitude and significance of repeatability in both variables depending on the year and whether they were corrected for body mass or body size. The patterns of repeatability observed among years also differed between the two variables. Our findings suggest that the relative ranking of individuals in winter metabolic performance is affected by local ecological conditions and can change within relatively short periods of time.

  1. Noninvasive in vivo imaging of oxygen metabolic rate in the retina.

    PubMed

    Liu, Wenzhong; Zhang, Hao F

    2014-01-01

    Precise and noninvasive measurement of retinal oxygen metabolic rate is important for retinal pathological investigations as well as retinal disease detection, which has not been achieved until recently. Here, we quantified retinal oxygen metabolic rate in rats by combining photoacoustic ophthalmoscopy with spectral domain-optical coherence tomography. We employed multi-wavelength photoacoustic ophthalmoscopy for oxygen saturation measurement and applied dual-ring scanning Doppler spectral domain-optical coherence tomography to image retinal blood flow. With retinal oxygen saturation and blood flow being measured, we determined the retinal oxygen metabolic rate in a typical rat to be 373.41 ± 88.04 ng/minute.

  2. Brain metabolism in autism. Resting cerebral glucose utilization rates as measured with positron emission tomography

    SciTech Connect

    Rumsey, J.M.; Duara, R.; Grady, C.; Rapoport, J.L.; Margolin, R.A.; Rapoport, S.I.; Cutler, N.R.

    1985-05-01

    The cerebral metabolic rate for glucose was studied in ten men (mean age = 26 years) with well-documented histories of infantile autism and in 15 age-matched normal male controls using positron emission tomography and (F-18) 2-fluoro-2-deoxy-D-glucose. Positron emission tomography was completed during rest, with reduced visual and auditory stimulation. While the autistic group as a whole showed significantly elevated glucose utilization in widespread regions of the brain, there was considerable overlap between the two groups. No brain region showed a reduced metabolic rate in the autistic group. Significantly more autistic, as compared with control, subjects showed extreme relative metabolic rates (ratios of regional metabolic rates to whole brain rates and asymmetries) in one or more brain regions.

  3. Skeletal Muscle Hypertrophy after Aerobic Exercise Training

    PubMed Central

    Konopka, Adam R.; Harber, Matthew P.

    2014-01-01

    Current dogma suggests aerobic exercise training has minimal effect on skeletal muscle size. We and others have demonstrated that aerobic exercise acutely and chronically alters protein metabolism and induces skeletal muscle hypertrophy. These findings promote an antithesis to the status quo by providing novel perspective on skeletal muscle mass regulation and insight into exercise-countermeasures for populations prone to muscle loss. PMID:24508740

  4. Evolution of metabolic rate in a parasitic wasp: the role of limitation in intrinsic resources.

    PubMed

    Moiroux, Joffrey; Giron, David; Vernon, Philippe; van Baaren, Joan; van Alphen, Jacques J M

    2012-07-01

    Metabolic rate, a physiological trait closely related to fitness traits, is expected to evolve in response to two main environmental variables: (1) climate, low metabolic rates being found in dry and hot regions when comparing populations originating from different climates in a common garden experiment and (2) resource limitations, low metabolic rates being selected when resources are limited. The main goal of this study was to investigate if differences in intrinsic resource limitations may have disrupted the expected evolution of metabolic rate in response to climate in a parasitic wasp. We compared CO(2) production of females from 4 populations of a Drosophila parasitoid, Leptopilina boulardi, as an estimate of their metabolic rate. Two populations from a hot and dry area able to synthesise lipids de novo at adult stage were compared with two populations originating from a mild and humid climate where no lipid accumulation during adult life was observed. These last females are thus more limited in lipids than the first ones. We observed that a high metabolic rate has been selected in hot and dry environments, contrarily to the results of a great majority of studies. We suggest that lipogenesis occurring there may have allowed the selection of a higher metabolic rate, as females are less limited in energetic resources than females from the mild environment. A high metabolic rate may have been selected there as it partly compensates for the long distances that females have to cross to find laying opportunities in distant orchards. We suggest that intrinsic resources should be integrated when investigating geographical variations in metabolism as this factor may disrupt evolution in response to climate.

  5. The influence of metabolic rate on longevity in the nematode Caenorhabditis elegans.

    PubMed

    Van Voorhies, Wayne A

    2002-12-01

    Much of the recent interest in aging research is due to the discovery of genes in a variety of model organisms that appear to modulate aging. A large amount of research has focused on the use of such long-lived mutants to examine the fundamental causes of aging. While model organisms do offer many advantages for studying aging, it also critical to consider the limitations of these systems. In particular, ectothermic (poikilothermic) organisms can tolerate a much larger metabolic depression than humans. Thus, considering only chronological longevity when assaying for long-lived mutants provides a limited perspective on the mechanisms by which longevity is increased. In order to provide true insight into the aging process additional physiological processes, such as metabolic rate, must also be assayed. This is especially true in the nematode Caenorhabditis elegans, which can naturally enter into a metabolically reduced state in which it survives many times longer than its usual lifetime. Currently it is seen as controversial if long-lived C. elegans mutants retain normal metabolic function. Resolving this issue requires accurately measuring the metabolic rate of C. elegans under conditions that minimize environmental stress. Additionally, the relatively small size of C. elegans requires the use of sensitive methodologies when determining metabolic rates. Several studies indicating that long-lived C. elegans mutants have normal metabolic rates may be flawed due to the use of inappropriate measurement conditions and techniques. Comparisons of metabolic rate between long-lived and wild-type C. elegans under more optimized conditions indicate that the extended longevity of at least some long-lived C. elegans mutants may be due to a reduction in metabolic rate, rather than an alteration of a metabolically independent genetic mechanism specific to aging.

  6. Cold climate specialization: adaptive covariation between metabolic rate and thermoregulation in pregnant vipers.

    PubMed

    Lourdais, Olivier; Guillon, Michaël; Denardo, Dale; Blouin-Demers, Gabriel

    2013-07-02

    We compared thermoregulatory strategies during pregnancy in two congeneric viperid snakes (Vipera berus and Vipera aspis) with parapatric geographic ranges. V. berus is a boreal specialist with the largest known distribution among terrestrial snakes while V. aspis is a south-European species. Despite contrasted climatic affinities, the two species displayed identical thermal preferences (Tset) in a laboratory thermal gradient. Under identical natural conditions, however, V. berus was capable of maintaining Tset for longer periods, especially when the weather was constraining. Consistent with the metabolic cold adaptation hypothesis, V. berus displayed higher standard metabolic rate at all temperatures considered. We used the thermal dependence of metabolic rate to calculate daily metabolic profiles from body temperature under natural conditions. The boreal specialist experienced higher daily metabolic rate and minimized gestation duration chiefly because of differences in the metabolic reaction norms, but also superior thermoregulatory efficiency. Under cold climates, thermal constraints should make precise thermoregulation costly. However, a shift in the metabolic reaction norm may compensate for thermal constraints and modify the cost-benefit balance of thermoregulation. Covariation between metabolic rate and thermoregulation efficiency is likely an important adaptation to cold climates.

  7. Thermal optima and tolerance in the eurythermic goldfish (Carassius auratus): relationships between whole-animal aerobic capacity and maximum heart rate.

    PubMed

    Ferreira, Elizabeth O; Anttila, Katja; Farrell, Anthony P

    2014-01-01

    The wide thermal tolerance range of a eurythermic fish (goldfish, Carassius auratus) was used to evaluate how temperature performance curves derived from maximum heart rate (fH) related to those for aerobic scope. For acclimation temperatures of 12°, 20°, and 28°C, optimum temperatures derived from aerobic scope curves (Topt) were 19.9° ± 0.4°, 19.3° ± 0.8°, and 28.7° ± 0.8°C, respectively. The Arrhenius breakpoint temperatures (TAB) for maximum fH were 21.5° ± 0.6°, 23.8° ± 0.9°, and 24.6° ± 0.5°C, respectively. The TQB (temperature where the incremental Q10 of maximum fH decreased abruptly below 1.9) was 24.0° ± 0.7° and 29.8° ± 0.6°C for the 12° and 28°C acclimation temperatures, respectively, and was within the Topt window (11.5°-30.3° and 26.9°-30.5°C, respectively), but TQB for the 20°C acclimation temperature (27.3° ± 0.6°C) was higher than the Topt window (15.4°-23.2°C). Warm acclimation increased the upper critical temperature (Tcrit; from 37.2° ± 0.7° to 44.7° ± 11.8°C) as well as the temperature that triggered a cardiac arrhythmia (Tarr; from 31.1° ± 0.7° to 39.3° ± 0.4°C). In conclusion, we propose that maximum fH and its associated rate transition temperatures (TAB, TQB, and Tarr) can be used to estimate the upper thermal tolerance of eurythermic as well as stenothermic fish independent of acclimation temperature. All the same, great care is needed with such evaluations. For the goldfish, while TAB and TQB were always within the Topt window for 90% of maximum aerobic scope and Topt was closely associated with TAB for 12°C-acclimated fish, TQB had the closest association after 28°C acclimation, and both TAB and TQB were above the Topt window after 20°C acclimation.

  8. The absorption and metabolism of a single L-menthol oral versus skin administration: Effects on thermogenesis and metabolic rate.

    PubMed

    Valente, Angelica; Carrillo, Andres E; Tzatzarakis, Manolis N; Vakonaki, Elena; Tsatsakis, Aristidis M; Kenny, Glen P; Koutedakis, Yiannis; Jamurtas, Athanasios Z; Flouris, Andreas D

    2015-12-01

    We investigated the absorption and metabolism pharmacokinetics of a single L-menthol oral versus skin administration and the effects on human thermogenesis and metabolic rate. Twenty healthy adults were randomly distributed into oral (capsule) and skin (gel) groups and treated with 10 mg kg(-1) L-menthol (ORALMENT; SKINMENT) or control (lactose capsule: ORALCON; water application: SKINCON) in a random order on two different days. Levels of serum L-menthol increased similarly in ORALMENT and SKINMENT (p > 0.05). L-menthol glucuronidation was greater in ORALMENT than SKINMENT (p < 0.05). Cutaneous vasoconstriction, rectal temperature and body heat storage showed greater increase following SKINMENT compared to ORALMENT and control conditions (p < 0.05). Metabolic rate increased from baseline by 18% in SKINMENT and 10% in ORALMENT and respiratory exchange ratio decreased more in ORALMENT (5.4%) than SKINMENT (4.8%) compared to control conditions (p < 0.05). Levels of plasma adiponectin and leptin as well as heart rate variability were similar to control following either treatment (p > 0.05). Participants reported no cold, shivering, discomfort, stress or skin irritation. We conclude that a single L-menthol skin administration increased thermogenesis and metabolic rate in humans. These effects are minor following L-menthol oral administration probably due to faster glucuronidation and greater blood menthol glucuronide levels.

  9. 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

  10. Regional cerebral glucose metabolic rate in human sleep assessed by positron emission tomography

    SciTech Connect

    Buchsbaum, M.S.; Wu, J.; Hazlett, E.; Sicotte, N.; Bunney, W.E. Jr. ); Gillin, J.C. )

    1989-01-01

    The cerebral metabolic rate of glucose was measured during nighttime sleep in 36 normal volunteers using positron emission tomography and fluorine-18-labeled 2-deoxyglucose (FDG). In comparison to waking controls, subjects given FDG during non-rapid eye movement (NREM) sleep showed about a 23% reduction in metabolic rate across the entire brain. This decrease was greater for the frontal than temporal or occipital lobes, and greater for basal ganglia and thalamus than cortex. Subjects in rapid eye movement (REM) sleep tended to have higher cortical metabolic rates than walking subjects. The cingulate gyrus was the only cortical structure to show a significant increase in glucose metabolic rate in REM sleep in comparison to waking. The basal ganglia were relatively more active on the right in REM sleep and symmetrical in NREM sleep.

  11. Cross-validation of recent and longstanding resting metabolic rate prediction equations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Resting metabolic rate (RMR) measurement is time consuming and requires specialized equipment. Prediction equations provide an easy method to estimate RMR; however, their accuracy likely varies across individuals. Understanding the factors that influence predicted RMR accuracy at the individual lev...

  12. Hybrid Dysfunction Expressed as Elevated Metabolic Rate in Male Ficedula Flycatchers.

    PubMed

    McFarlane, S Eryn; Sirkiä, Päivi M; Ålund, Murielle; Qvarnström, Anna

    2016-01-01

    Studies of ecological speciation are often biased towards extrinsic sources of selection against hybrids, resulting from intermediate hybrid morphology, but the knowledge of how genetic incompatibilities accumulate over time under natural conditions is limited. Here we focus on a physiological trait, metabolic rate, which is central to life history strategies and thermoregulation but is also likely to be sensitive to mismatched mitonuclear interactions. We measured the resting metabolic rate of male collared, and pied flycatchers as well as of naturally occurring F1 hybrid males, in a recent hybrid zone. We found that hybrid males had a higher rather than intermediate metabolic rate, which is indicative of hybrid physiological dysfunction. Fitness costs associated with elevated metabolic rate are typically environmentally dependent and exaggerated under harsh conditions. By focusing on male hybrid dysfunction in an eco-physiological trait, our results contribute to the general understanding of how combined extrinsic and intrinsic sources of hybrid dysfunction build up under natural conditions.

  13. Program for PET image alignment: Effects on calculated differences in cerebral metabolic rates for glucose

    SciTech Connect

    Phillips, R.L.; London, E.D.; Links, J.M.; Cascella, N.G. )

    1990-12-01

    A program was developed to align positron emission tomography images from multiple studies on the same subject. The program allowed alignment of two images with a fineness of one-tenth the width of a pixel. The indications and effects of misalignment were assessed in eight subjects from a placebo-controlled double-blind crossover study on the effects of cocaine on regional cerebral metabolic rates for glucose. Visual examination of a difference image provided a sensitive and accurate tool for assessing image alignment. Image alignment within 2.8 mm was essential to reduce variability of measured cerebral metabolic rates for glucose. Misalignment by this amount introduced errors on the order of 20% in the computed metabolic rate for glucose. These errors propagate to the difference between metabolic rates for a subject measured in basal versus perturbed states.

  14. Hybrid Dysfunction Expressed as Elevated Metabolic Rate in Male Ficedula Flycatchers

    PubMed Central

    McFarlane, S. Eryn; Sirkiä, Päivi M.; Ålund, Murielle; Qvarnström, Anna

    2016-01-01

    Studies of ecological speciation are often biased towards extrinsic sources of selection against hybrids, resulting from intermediate hybrid morphology, but the knowledge of how genetic incompatibilities accumulate over time under natural conditions is limited. Here we focus on a physiological trait, metabolic rate, which is central to life history strategies and thermoregulation but is also likely to be sensitive to mismatched mitonuclear interactions. We measured the resting metabolic rate of male collared, and pied flycatchers as well as of naturally occurring F1 hybrid males, in a recent hybrid zone. We found that hybrid males had a higher rather than intermediate metabolic rate, which is indicative of hybrid physiological dysfunction. Fitness costs associated with elevated metabolic rate are typically environmentally dependent and exaggerated under harsh conditions. By focusing on male hybrid dysfunction in an eco-physiological trait, our results contribute to the general understanding of how combined extrinsic and intrinsic sources of hybrid dysfunction build up under natural conditions. PMID:27583553

  15. The rise of oxygen and aerobic biochemistry.

    PubMed

    Saito, Mak A

    2012-01-11

    Analysis of conserved protein folding domains across extant genomes by Kim et al. in this issue of Structure provides insights into the timing of some of the earliest aerobic metabolisms to arise on Earth.

  16. Gene expression centroids that link with low intrinsic aerobic exercise capacity and complex disease risk.

    PubMed

    Kivelä, Riikka; Silvennoinen, Mika; Lehti, Maarit; Rinnankoski-Tuikka, Rita; Purhonen, Tatja; Ketola, Tarmo; Pullinen, Katri; Vuento, Meri; Mutanen, Niina; Sartor, Maureen A; Reunanen, Hilkka; Koch, Lauren G; Britton, Steven L; Kainulainen, Heikki

    2010-11-01

    A strong link exists between low aerobic exercise capacity and complex metabolic diseases. To probe this linkage, we utilized rat models of low and high intrinsic aerobic endurance running capacity that differ also in the risk for metabolic syndrome. We investigated in skeletal muscle gene-phenotype relationships that connect aerobic endurance capacity with metabolic disease risk factors. The study compared 12 high capacity runners (HCRs) and 12 low capacity runners (LCRs) from generation 18 of selection that differed by 615% for maximal treadmill endurance running capacity. On average, LCRs were heavier and had increased blood glucose, insulin, and triglycerides compared with HCRs. HCRs were higher for resting metabolic rate, voluntary activity, serum high density lipoproteins, muscle capillarity, and mitochondrial area. Bioinformatic analysis of skeletal muscle gene expression data revealed that many genes up-regulated in HCRs were related to oxidative energy metabolism. Seven mean mRNA expression centroids, including oxidative phosphorylation and fatty acid metabolism, correlated significantly with several exercise capacity and disease risk phenotypes. These expression-phenotype correlations, together with diminished skeletal muscle capillarity and mitochondrial area in LCR rats, support the general hypothesis that an inherited intrinsic aerobic capacity can underlie disease risks.

  17. Metabolic rate of the red panda, Ailurus fulgens, a dietary bamboo specialist.

    PubMed

    Fei, Yuxiang; Hou, Rong; Spotila, James R; Paladino, Frank V; Qi, Dunwu; Zhang, Zhihe

    2017-01-01

    The red panda (Ailurus fulgens) has a similar diet, primarily bamboo, and shares the same habitat as the giant panda, Ailuropoda melanoleuca. There are considerable efforts underway to understand the ecology of the red panda and to increase its populations in natural reserves. Yet it is difficult to design an effective strategy for red panda reintroduction if we do not understand its basic biology. Here we report the resting metabolic rate of the red panda and find that it is higher than previously measured on animals from a zoo. The resting metabolic rate was 0.290 ml/g/h (range 0.204-0.342) in summer and 0.361 ml/g/h in winter (range 0.331-0.406), with a statistically significant difference due to season and test temperature. Temperatures in summer were probably within the thermal neutral zone for metabolism but winter temperatures were below the thermal neutral zone. There was no difference in metabolic rate between male and female red pandas and no difference due to mass. Our values for metabolic rate were much higher than those measured by McNab for 2 red pandas from a zoo. The larger sample size (17), more natural conditions at the Panda Base and improved accuracy of the metabolic instruments provided more accurate metabolism measurements. Contrary to our expectations based on their low quality bamboo diet, the metabolic rates of red pandas were similar to mammals of the same size. Based on their metabolic rates red pandas would not be limited by their food supply in natural reserves.

  18. Metabolic rate of the red panda, Ailurus fulgens, a dietary bamboo specialist

    PubMed Central

    Fei, Yuxiang; Hou, Rong; Paladino, Frank V.; Qi, Dunwu; Zhang, Zhihe

    2017-01-01

    The red panda (Ailurus fulgens) has a similar diet, primarily bamboo, and shares the same habitat as the giant panda, Ailuropoda melanoleuca. There are considerable efforts underway to understand the ecology of the red panda and to increase its populations in natural reserves. Yet it is difficult to design an effective strategy for red panda reintroduction if we do not understand its basic biology. Here we report the resting metabolic rate of the red panda and find that it is higher than previously measured on animals from a zoo. The resting metabolic rate was 0.290 ml/g/h (range 0.204–0.342) in summer and 0.361 ml/g/h in winter (range 0.331–0.406), with a statistically significant difference due to season and test temperature. Temperatures in summer were probably within the thermal neutral zone for metabolism but winter temperatures were below the thermal neutral zone. There was no difference in metabolic rate between male and female red pandas and no difference due to mass. Our values for metabolic rate were much higher than those measured by McNab for 2 red pandas from a zoo. The larger sample size (17), more natural conditions at the Panda Base and improved accuracy of the metabolic instruments provided more accurate metabolism measurements. Contrary to our expectations based on their low quality bamboo diet, the metabolic rates of red pandas were similar to mammals of the same size. Based on their metabolic rates red pandas would not be limited by their food supply in natural reserves. PMID:28306740

  19. The intraspecific scaling of metabolic rate with body mass in fishes depends on lifestyle and temperature.

    PubMed

    Killen, Shaun S; Atkinson, David; Glazier, Douglas S

    2010-02-01

    Metabolic energy fuels all biological processes, and therefore theories that explain the scaling of metabolic rate with body mass potentially have great predictive power in ecology. A new model, that could improve this predictive power, postulates that the metabolic scaling exponent (b) varies between 2/3 and 1, and is inversely related to the elevation of the intraspecific scaling relationship (metabolic level, L), which in turn varies systematically among species in response to various ecological factors. We test these predictions by examining the effects of lifestyle, swimming mode and temperature on intraspecific scaling of resting metabolic rate among 89 species of teleost fish. As predicted, b decreased as L increased with temperature, and with shifts in lifestyle from bathyal and benthic to benthopelagic to pelagic. This effect of lifestyle on b may be related to varying amounts of energetically expensive tissues associated with different capacities for swimming during predator-prey interactions.

  20. Diagnosis of In Situ Metabolic State and Rates of Microbial Metabolism During In Situ Uranium Bioremediation with Molecular Techniques

    SciTech Connect

    Lovley, Derek R

    2012-11-28

    The goal of these projects was to develop molecule tools to tract the metabolic activity and physiological status of microorganisms during in situ uranium bioremediation. Such information is important in able to design improved bioremediation strategies. As summarized below, the research was highly successful with new strategies developed for estimating in situ rates of metabolism and diagnosing the physiological status of the predominant subsurface microorganisms. This is a first not only for groundwater bioremediation studies, but also for subsurface microbiology in general. The tools and approaches developed in these studies should be applicable to the study of microbial communities in a diversity of soils and sediments.

  1. WWOX loss activates aerobic glycolysis.

    PubMed

    Abu-Remaileh, Muhannad; Seewaldt, Victoria L; Aqeilan, Rami I

    2015-01-01

    Cancer cells undergo reprogramming of glucose metabolism to limit energy production to glycolysis-a state known as "aerobic glycolysis." Hypoxia-inducible factor 1 (HIF1α) is a transcription factor that regulates many genes responsible for this switch. As discussed here, new data suggest that the tumor suppressor WW domain-containing oxidoreductase (WWOX) modulates HIF1α, thereby regulating this metabolic state.

  2. WWOX loss activates aerobic glycolysis

    PubMed Central

    Abu-Remaileh, Muhannad; Seewaldt, Victoria L; Aqeilan, Rami I

    2015-01-01

    Cancer cells undergo reprogramming of glucose metabolism to limit energy production to glycolysis—a state known as “aerobic glycolysis.” Hypoxia-inducible factor 1 (HIF1α) is a transcription factor that regulates many genes responsible for this switch. As discussed here, new data suggest that the tumor suppressor WW domain-containing oxidoreductase (WWOX) modulates HIF1α, thereby regulating this metabolic state. PMID:27308416

  3. The relationship between body mass and field metabolic rate among individual birds and mammals.

    PubMed

    Hudson, Lawrence N; Isaac, Nick J B; Reuman, Daniel C

    2013-09-01

    1. The power-law dependence of metabolic rate on body mass has major implications at every level of ecological organization. However, the overwhelming majority of studies examining this relationship have used basal or resting metabolic rates, and/or have used data consisting of species-averaged masses and metabolic rates. Field metabolic rates are more ecologically relevant and are probably more directly subject to natural selection than basal rates. Individual rates might be more important than species-average rates in determining the outcome of ecological interactions, and hence selection. 2. We here provide the first comprehensive database of published field metabolic rates and body masses of individual birds and mammals, containing measurements of 1498 animals of 133 species in 28 orders. We used linear mixed-effects models to answer questions about the body mass scaling of metabolic rate and its taxonomic universality/heterogeneity that have become classic areas of controversy. Our statistical approach allows mean scaling exponents and taxonomic heterogeneity in scaling to be analysed in a unified way while simultaneously accounting for nonindependence in the data due to shared evolutionary history of related species. 3. The mean power-law scaling exponents of metabolic rate vs. body mass relationships were 0.71 [95% confidence intervals (CI) 0.625-0.795] for birds and 0.64 (95% CI 0.564-0.716) for mammals. However, these central tendencies obscured meaningful taxonomic heterogeneity in scaling exponents. The primary taxonomic level at which heterogeneity occurred was the order level. Substantial heterogeneity also occurred at the species level, a fact that cannot be revealed by species-averaged data sets used in prior work. Variability in scaling exponents at both order and species levels was comparable to or exceeded the differences 3/4-2/3 = 1/12 and 0.71-0.64. 4. Results are interpreted in the light of a variety of existing theories. In particular, results

  4. At the heart of aging: is it metabolic rate or stability?

    PubMed

    Olshansky, S Jay; Rattan, Suresh I S

    2005-01-01

    Foundational changes in science are rare, but in the field of biogerontology there is a new theory of aging that may shake things up. The conventional wisdom about duration of life is based on an old idea known as the "rate of living" theory, which suggests that aging is caused by the loss of some vital substance. The modern version of this theory is that duration of life is influenced by the relative speed of a species' resting metabolism. However, empirical evidence does not consistently support this hypothesis. In an article published recently by mathematician/biologist Lloyd Demetrius, it is suggested that the most important factor involved in duration of life is not metabolic rate or oxidative stress, but metabolic stability. If Demetrius is correct, his theory will have important implications for intervention research. For example, if the metabolic rate/oxidative stress theory is correct, efforts to intervene in the aging process should be directed at finding ways to reduce metabolic rate, lessen the production of reactive oxygen species (ROS), improve antioxidant defenses, or increase the quantity of antioxidants. If the metabolic stability hypothesis is correct, efforts to intervene in the aging process should be directed at finding ways to increase the stability of the steady state values of ROS, increase the robustness of metabolic networks, or improve the stability of antioxidant enzymes. For now there is reason to believe that Demetrius' theory deserves further consideration - whether it meets the test of a paradigm shift has yet to be determined.

  5. Detraining increases body fat and weight and decreases VO2peak and metabolic rate.

    PubMed

    Ormsbee, Michael J; Arciero, Paul J

    2012-08-01

    Competitive collegiate swimmers commonly take a month off from swim training after their last major competition. This abrupt cessation of intense physical training has not been well studied and may lead to physiopsychological decline. The purpose of this investigation was to examine the effects of swim detraining (DT) on body composition, aerobic fitness, resting metabolism, mood state, and blood lipids in collegiate swimmers. Eight healthy endurance-trained swimmers (V(O2)peak, 46.7 ± 10.8 ml · kg(-1) · min(-1)) performed 2 identical test days, 1 in the trained (TR) state and 1 in the detrained (~5 weeks) state (DT). Body composition and circumferences, maximal oxygen consumption (V(O2)peak), resting metabolism (RMR), blood lipids, and mood state were measured. After DT, body weight (TR, 68.9 ± 9.7 vs. DT, 69.8 ± 9.8 kg; p = 0.03), fat mass (TR, 14.7 ± 7.6 vs. DT, 16.5 ± 7.4 kg; p = 0.001), and waist circumference (TR, 72.7 ± 3.1 vs. DT, 73.8 ± 3.6 cm; p = 0.03) increased, whereas V(O2)peak (TR, 46.7 ± 10.8 vs. DT, 43.1 ± 10.3 ml · kg(-1) · min(-1); p = 0.02) and RMR (TR, 1.34 ± 0.2 vs. DT, 1.25 ± 0.17 kcal · min(-1); p = 0.008) decreased, and plasma triglycerides showed a trend to increase (p = 0.065). Our data suggest that DT after a competitive collegiate swim season adversely affects body composition, fitness, and metabolism. Athletes and coaches need to be aware of the negative consequences of detraining from swimming, and plan off-season training schedules accordingly to allow for adequate rest/recovery and prevent overuse injuries. It's equally important to mitigate the negative effects on body composition, aerobic fitness and metabolism so performance may continue to improve over the long term.

  6. Running and Metabolic Demands of Elite Rugby Union Assessed Using Traditional, Metabolic Power, and Heart Rate Monitoring Methods

    PubMed Central

    Dubois, Romain; Paillard, Thierry; Lyons, Mark; McGrath, David; Maurelli, Olivier; Prioux, Jacques

    2017-01-01

    The aims of this study were (1) to analyze elite rugby union game demands using 3 different approaches: traditional, metabolic and heart rate-based methods (2) to explore the relationship between these methods and (3) to explore positional differences between the backs and forwards players. Time motion analysis and game demands of fourteen professional players (24.1 ± 3.4 y), over 5 European challenge cup games, were analyzed. Thresholds of 14.4 km·h-1, 20 W.kg-1 and 85% of maximal heart rate (HRmax) were set for high-intensity efforts across the three methods. The mean % of HRmax was 80.6 ± 4.3 % while 42.2 ± 16.5% of game time was spent above 85% of HRmax with no significant differences between the forwards and the backs. Our findings also show that the backs cover greater distances at high-speed than forwards (% difference: +35.2 ± 6.6%; p<0.01) while the forwards cover more distance than the backs (+26.8 ± 5.7%; p<0.05) in moderate-speed zone (10-14.4 km·h-1). However, no significant difference in high-metabolic power distance was found between the backs and forwards. Indeed, the high-metabolic power distances were greater than high-speed running distances of 24.8 ± 17.1% for the backs, and 53.4 ± 16.0% for the forwards with a significant difference (+29.6 ± 6.0% for the forwards; p<0.001) between the two groups. Nevertheless, nearly perfect correlations were found between the total distance assessed using the traditional approach and the metabolic power approach (r = 0.98). Furthermore, there is a strong association (r = 0.93) between the high-speed running distance (assessed using the traditional approach) and the high-metabolic power distance. The HR monitoring methods demonstrate clearly the high physiological demands of professional rugby games. The traditional and the metabolic-power approaches shows a close correlation concerning their relative values, nevertheless the difference in absolute values especially for the high-intensity thresholds

  7. Do hand-held calorimeters provide reliable and accurate estimates of resting metabolic rate?

    PubMed

    Van Loan, Marta D

    2007-12-01

    This paper provides an overview of a new technique for indirect calorimetry and the assessment of resting metabolic rate. Information from the research literature includes findings on the reliability and validity of a new hand-held indirect calorimeter as well as use in clinical and field settings. Research findings to date are of mixed results. The MedGem instrument has provided more consistent results when compared to the Douglas bag method of measuring metabolic rate. The BodyGem instrument has been shown to be less accurate when compared to standard metabolic carts. Furthermore, when the Body Gem has been used with clinical patients or with under nourished individuals the results have not been acceptable. Overall, there is not a large enough body of evidence to definitively support the use of these hand-held devices for assessment of metabolic rate in a wide variety of clinical or research environments.

  8. Preferred Barefoot Step Frequency is Influenced by Factors Beyond Minimizing Metabolic Rate.

    PubMed

    Yandell, Matthew B; Zelik, Karl E

    2016-03-18

    Humans tend to increase their step frequency in barefoot walking, as compared to shod walking at the same speed. Based on prior studies and the energy minimization hypothesis we predicted that people make this adjustment to minimize metabolic cost. We performed an experiment quantifying barefoot walking metabolic rate at different step frequencies, specifically comparing preferred barefoot to preferred shod step frequency. We found that subjects increased their preferred frequency when walking barefoot at 1.4 m/s (~123 vs. ~117 steps/min shod, P = 2e-5). However, average barefoot walking metabolic rates at the preferred barefoot and shod step frequencies were not significantly different (P = 0.40). Instead, we observed subject-specific trends: five subjects consistently reduced (-8% average), and three subjects consistently increased (+10% average) their metabolic rate at preferred barefoot vs. preferred shod frequency. Thus, it does not appear that people ubiquitously select a barefoot step frequency that minimizes metabolic rate. We concluded that preferred barefoot step frequency is influenced by factors beyond minimizing metabolic rate, such as shoe properties and/or perceived comfort. Our results highlight the subject-specific nature of locomotor adaptations and how averaging data across subjects may obscure meaningful trends. Alternative experimental designs may be needed to better understand individual adaptations.

  9. Optimizing Flip Angles for Metabolic Rate Estimation in Hyperpolarized Carbon-13 MRI.

    PubMed

    Maidens, John; Gordon, Jeremy W; Arcak, Murat; Larson, Peder E Z

    2016-11-01

    Hyperpolarized carbon-13 magnetic resonance imaging has enabled the real-time observation of perfusion and metabolism in vivo. These experiments typically aim to distinguish between healthy and diseased tissues based on the rate at which they metabolize an injected substrate. However, existing approaches to optimizing flip angle sequences for these experiments have focused on indirect metrics of the reliability of metabolic rate estimates, such as signal variation and signal-to-noise ratio. In this paper we present an optimization procedure that focuses on maximizing the Fisher information about the metabolic rate. We demonstrate through numerical simulation experiments that flip angles optimized based on the Fisher information lead to lower variance in metabolic rate estimates than previous flip angle sequences. In particular, we demonstrate a 20% decrease in metabolic rate uncertainty when compared with the best competing sequence. We then demonstrate appropriateness of the mathematical model used in the simulation experiments with in vivo experiments in a prostate cancer mouse model. While there is no ground truth against which to compare the parameter estimates generated in the in vivo experiments, we demonstrate that our model used can reproduce consistent parameter estimates for a number of flip angle sequences.

  10. Preferred Barefoot Step Frequency is Influenced by Factors Beyond Minimizing Metabolic Rate

    NASA Astrophysics Data System (ADS)

    Yandell, Matthew B.; Zelik, Karl E.

    2016-03-01

    Humans tend to increase their step frequency in barefoot walking, as compared to shod walking at the same speed. Based on prior studies and the energy minimization hypothesis we predicted that people make this adjustment to minimize metabolic cost. We performed an experiment quantifying barefoot walking metabolic rate at different step frequencies, specifically comparing preferred barefoot to preferred shod step frequency. We found that subjects increased their preferred frequency when walking barefoot at 1.4 m/s (~123 vs. ~117 steps/min shod, P = 2e-5). However, average barefoot walking metabolic rates at the preferred barefoot and shod step frequencies were not significantly different (P = 0.40). Instead, we observed subject-specific trends: five subjects consistently reduced (‑8% average), and three subjects consistently increased (+10% average) their metabolic rate at preferred barefoot vs. preferred shod frequency. Thus, it does not appear that people ubiquitously select a barefoot step frequency that minimizes metabolic rate. We concluded that preferred barefoot step frequency is influenced by factors beyond minimizing metabolic rate, such as shoe properties and/or perceived comfort. Our results highlight the subject-specific nature of locomotor adaptations and how averaging data across subjects may obscure meaningful trends. Alternative experimental designs may be needed to better understand individual adaptations.

  11. Mass and temperature dependence of metabolic rate in litter and soil invertebrates.

    PubMed

    Meehan, Timothy D

    2006-01-01

    Metabolic scaling theory provides a framework for modeling the combined mass and temperature dependence of metabolic rate. The theory predicts that whole-organism metabolic rate should scale with body mass raised to the 3/4 power as a consequence of the physical characteristics of internal distribution networks. Metabolic rate is predicted to vary with absolute body temperature, T, according to the Boltzmann factor, e(-E/kT), where E is the apparent activation energy of biochemical reactions, 0.2-1.2 eV, and k is Boltzmann's constant. I evaluated those predictions, using a compilation of published data on the metabolic rates of litter- and soil-dwelling earthworms, isopods, oribatid mites, springtails, and spiders. Earthworms, oribatid mites, springtails, and spiders had mass-scaling exponents that were statistically indistinguishable from the expected value of 0.75. The scaling exponent for terrestrial isopods, 0.91, was significantly greater than expected. All taxa had apparent activation energies within the predicted range of 0.2-1.2 eV. Activation energies for isopods, oribatid mites, springtails, and spiders were not significantly different from the average expected value of 0.6 eV, while the activation energy for earthworms, 0.25 eV, was significantly lower than 0.6 eV. Updated equations for estimating metabolic rate from body mass and environmental temperature are given for investigations into the ecological energetics of litter and soil animals.

  12. A decreased metabolic clearance rate of aldosterone in benign essential hypertension

    PubMed Central

    Nowaczynski, W.; Kuchel, O.; Genest, J.

    1971-01-01

    Aldosterone secretion rate, metabolic clearance rate, and/or plasma concentration were determined in 16 patients with benign, uncomplicated essential hypertension and compared with those of control subjects. The mean metabolic clearance rate of aldosterone in 10 patients was significantly (P < 0.001) lower (mean 867 liters of plasma/day per m2 ±270 SD) than in a group of 7 healthy subjects (mean 1480 liters/day per m2 ±265 SD). Secretion rates in 13 patients (including the 10 already mentioned) tended to be low (83 ±43 vs. 109 ±54 μg/day) and plasma concentrations tended to be high (13.6 ±4.6 vs. 7.5 ±4.8 ng/100 ml), but neither of these differences was statistically significant. The lower metabolic clearance rate could account for elevated plasma concentrations of aldosterone even when the secretion rate is normal or low. Measurement of secretion rate or urinary excretion only is therefore insufficient to establish the presence and/or mode of evolution of hyperaldosteronism. Failure of the aldosterone secretion to adapt fully to a decreased aldosterone metabolic clearance rate (MCR) could explain the state of relative hyperaldosteronism in patients with benign essential hypertension, even when the secretion rate and the urinary excretion rate are in the normal range. PMID:5116208

  13. Effects of parasites and antigenic challenge on metabolic rates and thermoregulation in northern red-backed voles (Myodes rutilus).

    PubMed

    Novikov, Eugene; Kondratyuk, Ekaterina; Petrovski, Dmitry; Krivopalov, Anton; Moshkin, Mikhail

    2015-12-01

    Perturbations in host energetics are considered to be an essential pathway for parasite impact on host fitness. However, direct estimations of parasite-induced variations in basal metabolic rates of vertebrate hosts have so far provided contradictory results. The energy requirements of immunity and other vital functions may be compromised in energy-demanding conditions in comparison to comfortable conditions; therefore, in our study performed on the wild red-backed vole, Myodes rutilus, we compared the values of indices that reflect metabolic and thermoregulatory responses to acute cooling in individuals that had been naturally infected by gut helminths or Ixodes persulcatus taiga ticks to individuals with no signs of infestation. To consider the possible effects of an acquired immune response on host energetics, we also injected some of the tested individuals with sheep red blood cells (SRBC). Red-backed voles infected by the nematode Heligmosomum mixtum injected with SRBC showed significantly lower cold-induced maximum oxygen consumption than the saline control. Additionally, individuals infected with H. mixtum showed significantly lower oxygen consumption during the final minute of the 15-min acute cooling period and a significantly greater decline in body temperature than individuals free from helminths. In individuals concurrently infected by H. mixtum and the cestodes Arostrilepis horrida, these indices did not differ from helminth-free individuals. The number of ticks simultaneously parasitizing the voles at the moment of capture correlated positively with their SMR. Our results suggest that even natural parasites produce deleterious effects on host aerobic capacity and thermoregulatory abilities, although the effects of different parasites might not be additive.

  14. Daily patterns of metabolic rate among New Zealand lizards (Reptilia: Lacertilia: Diplodactylidae and Scincidae).

    PubMed

    Hare, Kelly M; Pledger, Shirley; Thompson, Michael B; Miller, John H; Daugherty, Charles H

    2006-01-01

    In addition to the effects of temperature fluctuations on metabolic rate, entrained endogenous rhythms in metabolism, which are independent of temperature fluctuations, may be important in overall energy metabolism in ectotherms. Daily entrained endogenous rhythms may serve as energy-conserving mechanisms during an animal's active or inactive phase. However, because nocturnal lizards often take advantage of thermal opportunities during the photophase (light), their daily metabolic rhythms may be less pronounced than those of diurnal species. We measured the rate of oxygen consumption (VO(2)) as an index of metabolic rate of eight temperate lizard species (four nocturnal, three diurnal, and one crepuscular/diurnal; n = 7-14) over 24 h at 13 degrees C and in constant darkness to test whether daily patterns (including amplitude, magnitude, and time of peak VO(2)) of metabolic rate in lizards differ with activity period. We also tested for phylogenetic differences in metabolic rate between skinks and geckos. Three daily patterns were evident: 24-h cycle, 12-h cycle, or no daily cycle. The skink Cyclodina aenea has a 12-h crepuscular pattern of oxygen consumption. In four other species, VO(2) increased with, or in anticipation of, the active part of the day, but three species had rhythms offset from their active phase. Although not correlated with activity period or phylogeny, amplitude of VO(2) may be correlated with whether a species is temperate or tropical. In conclusion, the metabolic rate of many species does not always correlate with the recorded activity period. The dichotomy of ecology and physiology may be clarified by more in-depth studies of species behaviors and activity periods.

  15. Cellular metabolic rate is influenced by life-history traits in tropical and temperate birds.

    PubMed

    Jimenez, Ana Gabriela; Van Brocklyn, James; Wortman, Matthew; Williams, Joseph B

    2014-01-01

    In general, tropical birds have a "slow pace of life," lower rates of whole-animal metabolism and higher survival rates, than temperate species. A fundamental challenge facing physiological ecologists is the understanding of how variation in life-history at the whole-organism level might be linked to cellular function. Because tropical birds have lower rates of whole-animal metabolism, we hypothesized that cells from tropical species would also have lower rates of cellular metabolism than cells from temperate species of similar body size and common phylogenetic history. We cultured primary dermal fibroblasts from 17 tropical and 17 temperate phylogenetically-paired species of birds in a common nutritive and thermal environment and then examined basal, uncoupled, and non-mitochondrial cellular O2 consumption (OCR), proton leak, and anaerobic glycolysis (extracellular acidification rates [ECAR]), using an XF24 Seahorse Analyzer. We found that multiple measures of metabolism in cells from tropical birds were significantly lower than their temperate counterparts. Basal and uncoupled cellular metabolism were 29% and 35% lower in cells from tropical birds, respectively, a decrease closely aligned with differences in whole-animal metabolism between tropical and temperate birds. Proton leak was significantly lower in cells from tropical birds compared with cells from temperate birds. Our results offer compelling evidence that whole-animal metabolism is linked to cellular respiration as a function of an animal's life-history evolution. These findings are consistent with the idea that natural selection has uniquely fashioned cells of long-lived tropical bird species to have lower rates of metabolism than cells from shorter-lived temperate species.

  16. Cellular Metabolic Rate Is Influenced by Life-History Traits in Tropical and Temperate Birds

    PubMed Central

    Jimenez, Ana Gabriela; Van Brocklyn, James; Wortman, Matthew; Williams, Joseph B.

    2014-01-01

    In general, tropical birds have a “slow pace of life,” lower rates of whole-animal metabolism and higher survival rates, than temperate species. A fundamental challenge facing physiological ecologists is the understanding of how variation in life-history at the whole-organism level might be linked to cellular function. Because tropical birds have lower rates of whole-animal metabolism, we hypothesized that cells from tropical species would also have lower rates of cellular metabolism than cells from temperate species of similar body size and common phylogenetic history. We cultured primary dermal fibroblasts from 17 tropical and 17 temperate phylogenetically-paired species of birds in a common nutritive and thermal environment and then examined basal, uncoupled, and non-mitochondrial cellular O2 consumption (OCR), proton leak, and anaerobic glycolysis (extracellular acidification rates [ECAR]), using an XF24 Seahorse Analyzer. We found that multiple measures of metabolism in cells from tropical birds were significantly lower than their temperate counterparts. Basal and uncoupled cellular metabolism were 29% and 35% lower in cells from tropical birds, respectively, a decrease closely aligned with differences in whole-animal metabolism between tropical and temperate birds. Proton leak was significantly lower in cells from tropical birds compared with cells from temperate birds. Our results offer compelling evidence that whole-animal metabolism is linked to cellular respiration as a function of an animal’s life-history evolution. These findings are consistent with the idea that natural selection has uniquely fashioned cells of long-lived tropical bird species to have lower rates of metabolism than cells from shorter-lived temperate species. PMID:24498080

  17. The effects of gait strategy on metabolic rate and indicators of stability during downhill walking.

    PubMed

    Monsch, E D; Franz, C O; Dean, J C

    2012-07-26

    When walking at a given speed, humans often appear to prefer gait patterns that minimize metabolic rate, thereby maximizing metabolic economy. However, recent experiments have demonstrated that humans do not maximize economy when walking downhill. The purpose of this study was to investigate whether this non-metabolically optimal behavior is the result of a trade-off between metabolic economy and gait stability. We hypothesized that humans have the ability to modulate their gait strategy to increase either metabolic economy or stability, but that increase in one measure will be accompanied by decrease in the other. Subjects walked downhill using gait strategies ranging from risky to conservative, which were either prescribed by verbal instructions or induced by the threat of perturbations. We quantified spatiotemporal gait characteristics, metabolic rate and several indicators of stability previously associated with fall risk: stride period variability; step width variability; Lyapunov exponents; Floquet multipliers; and stride period fractal index. When subjects walked using conservative gait strategies, stride periods and lengths decreased, metabolic rate increased, and anteroposterior maximum Lyapunov exponents increased, which has previously been interpreted as an indicator of decreased stability. These results do not provide clear support for the proposed trade-off between economy and stability, particularly when stability is approximated using complex metrics. However, several gait pattern changes previously linked to increased fall risk were observed when our healthy subjects walked with a conservative strategy, suggesting that these changes may be a response to, rather than a cause of, increased fall risk.

  18. Temperature dependence of metabolic rates for microbial growth, maintenance, and survival

    PubMed Central

    Price, P. Buford; Sowers, Todd

    2004-01-01

    Our work was motivated by discoveries of prokaryotic communities that survive with little nutrient in ice and permafrost, with implications for past or present microbial life in Martian permafrost and Europan ice. We compared the temperature dependence of metabolic rates of microbial communities in permafrost, ice, snow, clouds, oceans, lakes, marine and freshwater sediments, and subsurface aquifer sediments. Metabolic rates per cell fall into three groupings: (i) a rate, μg(T), for growth, measured in the laboratory at in situ temperatures with minimal disturbance of the medium; (ii) a rate, μm(T), sufficient for maintenance of functions but for a nutrient level too low for growth; and (iii) a rate, μs(T), for survival of communities imprisoned in deep glacial ice, subsurface sediment, or ocean sediment, in which they can repair macromolecular damage but are probably largely dormant. The three groups have metabolic rates consistent with a single activation energy of ≈110 kJ and that scale as μg(T):μm(T):μs(T) ≈ 106:103:1. There is no evidence of a minimum temperature for metabolism. The rate at -40°C in ice corresponds to ≈10 turnovers of cellular carbon per billion years. Microbes in ice and permafrost have metabolic rates similar to those in water, soil, and sediment at the same temperature. This finding supports the view that, far below the freezing point, liquid water inside ice and permafrost is available for metabolism. The rate μs(T) for repairing molecular damage by means of DNA-repair enzymes and protein-repair enzymes such as methyltransferase is found to be comparable to the rate of spontaneous molecular damage. PMID:15070769

  19. Long-term caloric restriction reduces metabolic rate and heart rate under cool and thermoneutral conditions in FBNF1 rats.

    PubMed

    Knight, W David; Witte, M M; Parsons, A D; Gierach, M; Overton, J Michael

    2011-05-01

    The long-term metabolic and cardiovascular responses to caloric restriction (CR) are poorly understood. We examined the responses to one year of CR in FBNF1 rats housed in cool (COOL; T(a)=15 °C) or thermoneutral (TMN; T(a)=30 °C) conditions. Rats were acclimated to COOL or TMN for 2 months, instrumented for cardiovascular telemetry and studied in calorimeters. Baseline caloric intake, oxygen consumption (VO(2)), mean arterial blood pressure (MAP), and heart rate (HR) were determined prior to assignment to ad lib (AL) or CR groups (30-40% CR) within each T(a) (n = 8). Groups of rats were studied after 10 weeks CR, one year CR, and after 4 days of re-feeding. Both 10 weeks and one year of CR reduced HR and VO(2) irrespective of T(a). Evaluation of the relationship between metabolic organ mass (liver, heart, brain, and kidney mass) and energy expenditure revealed a clear shift induced by CR to reduce expenditure per unit metabolic mass in both COOL and TMN groups. Re-feeding resulted in prompt elevations of HR and VO(2) to levels observed in control rats. These findings are consistent with the hypothesis that long term CR produces sustained reductions in metabolic rate and heart rate in rats.

  20. Reduced metabolic rate and oxygen radicals production in stored insect sperm.

    PubMed

    Ribou, Anne-Cécile; Reinhardt, Klaus

    2012-06-07

    Females of internally fertilizing species can significantly extend sperm lifespan and functionality during sperm storage. The mechanisms for such delayed cellular senescence remain unknown. Here, we apply current hypotheses of cellular senescence developed for diploid cells to sperm cells, and empirically test opposing predictions on the relationship between sperm metabolic rate and oxygen radical production in an insect model, the cricket Gryllus bimaculatus. Using time-resolved microfluorimetry, we found a negative correlation between metabolic rate (proportion of protein-bound NAD[P]H) and in situ intracellular oxygen radicals production in freshly ejaculated sperm. In contrast, sperm stored by females for periods of 1 h to 26 days showed a positive correlation between metabolic rate and oxygen radicals production. At the same time, stored sperm showed a 37 per cent reduced metabolic rate, and 42 per cent reduced reactive oxygen species (ROS) production, compared with freshly ejaculated sperm. Rank differences between males in ROS production and metabolic rate observed in ejaculated sperm did not predict rank differences in stored sperm. Our method of simultaneously measuring ROS production and metabolic rate of the same sample has the advantage of providing data that are independent of sperm density and any extracellular antioxidants that are proteins. Our method also excludes effects owing to accumulated hydrogen peroxide. Our results unify aspects of competing theories of cellular ageing and suggest that reducing metabolic rate may be an important means of extending stored sperm lifespan and functionality in crickets. Our data also provide a possible explanation for why traits of ejaculates sampled from the male may be rather poor predictors of paternity in sexual selection studies and likelihood of pregnancy in reproductive medicine.

  1. The metabolic clearance rate of corticosterone in lean and obese male Zucker rats

    SciTech Connect

    White, B.D.; Corll, C.B.; Porter, J.R.

    1989-06-01

    The obese Zucker rat is an animal model of human juvenile-onset obesity. These rats exhibit numerous endocrine and metabolic abnormalities. Adrenalectomy of obese rats has been shown to reduce or reverse several of these abnormalities, thereby implying that corticosterone may contribute to the expression of obesity in this animal. Furthermore, it has been shown that the circadian rhythm of plasma corticosterone is disturbed in obese Zucker rats resulting in elevated morning plasma corticosterone concentrations in obese rats as compared to lean rats. In a effort to better elucidate the mechanism of the elevated morning levels of plasma corticosterone, the metabolic clearance rate of corticosterone was determined in the morning for lean and obese male Zucker rats (12 to 20 weeks). Additionally, the biliary and urinary excretion of labeled corticosterone and/or its metabolites were determined. The metabolic clearance rate of corticosterone was significantly greater in obese rats than in their lean counterparts. Both the metabolic clearance rate and the volume of compartments significantly correlated with body weight. No correlation was found between body weight and the elimination rate constant. The increased metabolic clearance rate of obese rats appeared to be due to an increase in the physiologic distribution of corticosterone and not to an alteration in the enzymes responsible for corticosterone metabolism. It appears that the metabolic clearance rate of corticosterone in obese Zucker rats does not contribute to elevated morning concentrations of plasma corticosterone previously observed in these animals. It suggests that the adrenal corticosterone secretion rate must actually be greater than one would expect from the plasma corticosterone concentrations alone.

  2. Measurement of flying and diving metabolic rate in wild animals: Review and recommendations.

    PubMed

    Elliott, Kyle H

    2016-12-01

    Animals' abilities to fly long distances and dive to profound depths fascinate earthbound researchers. Due to the difficulty of making direct measurements during flying and diving, many researchers resort to modeling so as to estimate metabolic rate during each of those activities in the wild, but those models can be inaccurate. Fortunately, the miniaturization, customization and commercialization of biologgers has allowed researchers to increasingly follow animals on their journeys, unravel some of their mysteries and test the accuracy of biomechanical models. I provide a review of the measurement of flying and diving metabolic rate in the wild, paying particular attention to mass loss, doubly-labelled water, heart rate and accelerometry. Biologgers can impact animal behavior and influence the very measurements they are designed to make, and I provide seven guidelines for the ethical use of biologgers. If biologgers are properly applied, quantification of metabolic rate across a range of species could produce robust allometric relationships that could then be generally applied. As measuring flying and diving metabolic rate in captivity is difficult, and often not directly translatable to field conditions, I suggest that applying multiple techniques in the field to reinforce one another may be a viable alternative. The coupling of multi-sensor biologgers with biomechanical modeling promises to improve precision in the measurement of flying and diving metabolic rate in wild animals.

  3. Does metabolic rate and evaporative water loss reflect differences in migratory strategy in sexually dimorphic hoverflies?

    PubMed

    Tomlinson, Sean; Menz, Myles H M

    2015-12-01

    A typical explanation for ecologically stable strategies that apply to only a proportion of a population, is bet hedging, where increased reproductive success offsets reduced reproductive rate. One such is partial migration, where only a proportion of a population moves seasonally to avoid inclement climatic conditions. Bet hedging may overlook unseen costs to maintain broad physiological resilience, implied by encountering a breadth of environmental conditions. We investigated the physiological correlates of partial migration by measuring standard metabolic rates, and rates of evaporative water loss, and then estimating upper and lower thermal tolerance in males and females of two hoverfly species, Episyrphus balteatus and Eristalis tenax. In central Europe, females of these species may either migrate or overwinter, whereas males may migrate south to the Mediterranean, but have not been found overwintering. Both species were sexually dimorphic; female Ep. balteatus were lighter than males, but female Er. tenax were heavier than males. While allometrically- corrected metabolic rate in both species increased with temperature, the most parsimonious models included no sex-specific differences in metabolic rate for either species. Evaporative water loss of both species also increased with temperature, but was higher for females of both species than males. Assuming that resting metabolism is congruent with the activity requirements of migration, highly consistent thermal tolerance and metabolic rate suggests that any given fly could migrate, although water loss patterns suggest that females may be less well-adapted to Mediterranean climates. We infer that partial migration probably results from the imperatives of their reproductive strategies.

  4. Behavioral and physiological significance of minimum resting metabolic rate in king penguins.

    PubMed

    Halsey, L G; Butler, P J; Fahlman, A; Woakes, A J; Handrich, Y

    2008-01-01

    Because fasting king penguins (Aptenodytes patagonicus) need to conserve energy, it is possible that they exhibit particularly low metabolic rates during periods of rest. We investigated the behavioral and physiological aspects of periods of minimum metabolic rate in king penguins under different circumstances. Heart rate (f(H)) measurements were recorded to estimate rate of oxygen consumption during periods of rest. Furthermore, apparent respiratory sinus arrhythmia (RSA) was calculated from the f(H) data to determine probable breathing frequency in resting penguins. The most pertinent results were that minimum f(H) achieved (over 5 min) was higher during respirometry experiments in air than during periods ashore in the field; that minimum f(H) during respirometry experiments on water was similar to that while at sea; and that RSA was apparent in many of the f(H) traces during periods of minimum f(H) and provides accurate estimates of breathing rates of king penguins resting in specific situations in the field. Inferences made from the results include that king penguins do not have the capacity to reduce their metabolism to a particularly low level on land; that they can, however, achieve surprisingly low metabolic rates at sea while resting in cold water; and that during respirometry experiments king penguins are stressed to some degree, exhibiting an elevated metabolism even when resting.

  5. Scaling of metabolic rate on body mass in small laboratory mammals

    NASA Technical Reports Server (NTRS)

    Pace, N.; Rahlmann, D. F.; Smith, A. H.

    1980-01-01

    The scaling of metabolic heat production rate on body mass is investigated for five species of small laboratory mammal in order to define selection of animals of metabolic rates and size range appropriate for the measurement of changes in the scaling relationship upon exposure to weightlessness in Shuttle/Spacelab experiment. Metabolic rates were measured according to oxygen consumption and carbon dioxide production for individual male and female Swiss-Webster mice, Syrian hamsters, Simonsen albino rats, Hartley guinea pigs and New Zealand white rabbits, which range in mass from 0.05 to 5 kg mature body size, at ages of 1, 2, 3, 5, 8, 12, 18 and 24 months. The metabolic intensity, defined as the heat produced per hour per kg body mass, is found to decrease dramatically with age until the animals are 6 to 8 months old, with little or no sex difference. When plotted on a logarithmic graph, the relation of metabolic rate to total body mass is found to obey a power law of index 0.676, which differs significantly from the classical value of 0.75. When the values for the mice are removed, however, an index of 0.749 is obtained. It is thus proposed that six male animals, 8 months of age, of each of the four remaining species be used to study the effects of gravitational loading on the metabolic energy requirements of terrestrial animals.

  6. Pim-2 Modulates Aerobic Glycolysis and Energy Production during the Development of Colorectal Tumors.

    PubMed

    Zhang, Xue-hui; Yu, Hong-liang; Wang, Fu-jing; Han, Yong-long; Yang, Wei-liang

    2015-01-01

    Tumor cells have higher rates of glucose uptake and aerobic glycolysis to meet energy demands for proliferation and metastasis. The characteristics of increased glucose uptake, accompanied with aerobic glycolysis, has been exploited for the diagnosis of cancers. Although much progress has been made, the mechanisms regulating tumor aerobic glycolysis and energy production are still not fully understood. Here, we demonstrate that Pim-2 is required for glycolysis and energy production in colorectal tumor cells. Our results show that Pim-2 is highly expressed in colorectal tumor cells, and may be induced by nutrient stimulation. Activation of Pim-2 in colorectal cells led to increase glucose utilization and aerobic glycolysis, as well as energy production. While knockdown of Pim-2 decreased energy production in colorectal tumor cells and increased their susceptibility to apoptosis. Moreover, the effects of Pim-2 kinase on aerobic glycolysis seem to be partly dependent on mTORC1 signaling, because inhibition of mTORC1 activity reversed the aerobic glycolysis mediated by Pim-2. Our findings suggest that Pim-2-mediated aerobic glycolysis is critical for monitoring Warburg effect in colorectal tumor cells, highlighting Pim-2 as a potential metabolic target for colorectal tumor therapy.

  7. Quantitative determinants of aerobic glycolysis identify flux through the enzyme GAPDH as a limiting step.

    PubMed

    Shestov, Alexander A; Liu, Xiaojing; Ser, Zheng; Cluntun, Ahmad A; Hung, Yin P; Huang, Lei; Kim, Dongsung; Le, Anne; Yellen, Gary; Albeck, John G; Locasale, Jason W

    2014-07-09

    Aerobic glycolysis or the Warburg Effect (WE) is characterized by the increased metabolism of glucose to lactate. It remains unknown what quantitative changes to the activity of metabolism are necessary and sufficient for this phenotype. We developed a computational model of glycolysis and an integrated analysis using metabolic control analysis (MCA), metabolomics data, and statistical simulations. We identified and confirmed a novel mode of regulation specific to aerobic glycolysis where flux through GAPDH, the enzyme separating lower and upper glycolysis, is the rate-limiting step in the pathway and the levels of fructose (1,6) bisphosphate (FBP), are predictive of the rate and control points in glycolysis. Strikingly, negative flux control was found and confirmed for several steps thought to be rate-limiting in glycolysis. Together, these findings enumerate the biochemical determinants of the WE and suggest strategies for identifying the contexts in which agents that target glycolysis might be most effective.

  8. Are Intensified Physical Education Sessions Able to Elicit Heart Rate at a Sufficient Level To Promote Aerobic Fitness in Adolescents?

    ERIC Educational Resources Information Center

    Baquet, Georges; Berthoin, Serge; Van Praagh, Emmanuel

    2002-01-01

    Determined the effects of intensified physical education sessions on adolescents divided into two groups: high intensity running group (HIRG) and high intensity jumping group (HIJG). Heart rate (HR) was monitored during sessions. There was no significant difference between mean HR for HIRG and HIJG. Mean HR was significantly lower for the control…

  9. Effects of starvation and molting on the metabolic rate of the bed bug (Cimex lectularius L.).

    PubMed

    DeVries, Zachary C; Kells, Stephen A; Appel, Arthur G

    2015-01-01

    The bed bug (Cimex lectularius L.) is a common hematophagous pest in the urban environment and is capable of surviving extended periods of starvation. However, the relationship between starvation and metabolism in bed bugs is not well understood. To better understand this relationship, we measured the metabolism of all life stages for >900 h after feeding (starvation) using closed-system respirometry. Measurements were made around molting for the immature life stages, which occurs only after a blood meal. In addition, both mated and unmated adults were measured. Starvation and molting had significant effects on the metabolism of the bed bug. Mass-specific metabolic rate (V(O2); mL g(-1) h(-1)) declined in a curvilinear fashion with the period of starvation for adults and with the postmolting period for immature bed bugs (used to standardize all immature life stages). A standard curve was developed to depict the generalized pattern of metabolic decline observed in all life stages that molted. Individual metabolic comparisons among life stages that molted revealed some differences in metabolic rate between unmated males and females. In addition, the mass scaling coefficient was found to decline with starvation time (postmolting time) for all life stages that molted. In most life stages, the ratio of V(CO2) to V(O2) (respiratory exchange ratio) declined over time, indicating a change in metabolic substrate with starvation. Finally, daily percent loss in body mass declined in a pattern similar to that of V(O2). The observed patterns in metabolic decline are evaluated in relation to the life history of bed bugs. In addition, the evolutionary development of these patterns is discussed. The metabolic pattern after feeding was also found to share several similarities with that of other ectothermic species.

  10. Morphological and physiological idiosyncrasies lead to interindividual variation in flight metabolic rate in worker bumblebees (Bombus impatiens).

    PubMed

    Skandalis, Dimitri A; Darveau, Charles-A

    2012-01-01

    Although intraspecific variation in metabolic rate is associated with variation in body size, similarly sized individuals nonetheless vary greatly. At similar masses, hovering bumblebee workers (Bombus impatiens) can differ in metabolic rate up to twofold. We examined how such interindividual variation arises by studying covariation of flight metabolic rate with morphological and other physiological parameters. Body size alone explained roughly half the variation in flight metabolic rate. The remaining variation could be explained as the outcome of variation in wing morphology and possibly an association with variation in flight muscle metabolic enzyme activities. As shown using statistical models, for a given mass, higher metabolic rate was correlated with both higher thoracic temperature and higher wing stroke frequency, in turn resulting from smaller wing surface area. When organismal and cellular metabolism for a given mass were linked, variation in metabolic rate was positively correlated with the activities of trehalase and hexokinase. Altogether, covariation with morphology and other physiological parameters explains up to 75% of the variation in metabolic rate. We also investigated the role of flight experience and show that neither flight restriction nor the number of lifetime flights affected flight energetics or flight muscle phenotype. Additionally, manipulating the level of wing asymmetry increased flight wing stroke frequency, metabolic rate, and thoracic temperature, but it did not alter enzyme activity. We conclude that idiosyncrasies in body morphology largely explained interindividual variation in flight metabolic rate but flight muscle metabolic phenotype shows little variation associated with differences in flight experience.

  11. Activity affects intraspecific body-size scaling of metabolic rate in ectothermic animals.

    PubMed

    Glazier, Douglas Stewart

    2009-10-01

    Metabolic rate is commonly thought to scale with body mass (M) to the 3/4 power. However, the metabolic scaling exponent (b) may vary with activity state, as has been shown chiefly for interspecific relationships. Here I use a meta-analysis of literature data to test whether b changes with activity level within species of ectothermic animals. Data for 19 species show that b is usually higher during active exercise (mean +/- 95% confidence limits = 0.918 +/- 0.038) than during rest (0.768 +/- 0.069). This significant upward shift in b to near 1 is consistent with the metabolic level boundaries hypothesis, which predicts that maximal metabolic rate during exercise should be chiefly influenced by volume-related muscular power production (scaling as M (1)). This dependence of b on activity level does not appear to be a simple temperature effect because body temperature in ectotherms changes very little during exercise.

  12. Interplay between metabolic rate and diet quality in the South American fox, Pseudalopex culpaeus.

    PubMed

    Silva, Sergio I; Jaksic, Fabian M; Bozinovic, Francisco

    2004-01-01

    We studied the metabolic costs associated with the ingestion of peppertree fruits (Schinus molle) in the culpeo fox, Pseudalopex culpaeus, the second largest canid in South America. Throughout its range of distribution, this fox feeds on rodents and other small vertebrates, and also on peppertree fruits, which represent 98% of total fruits consumed in semiarid Chile. Peppertree contains a high diversity of phytochemicals. Foxes feeding on diets containing rats and peppertree fruits (mixed diets) exhibited a 98.9% increase in basal rate of metabolism when compared to rat-acclimated foxes. Thus, acute ingestion of chemically defended fruits has an energetic cost for the fox, reflected in higher values of basal metabolism. Increased metabolic rates may be associated with increased protein synthesis for detoxification and for tissue repair, including the production of biotransformation enzymes.

  13. Low metabolic rates in salamanders are correlated with weak selective constraints on mitochondrial genes.

    PubMed

    Chong, Rebecca A; Mueller, Rachel Lockridge

    2013-03-01

    Mitochondria are the site for the citric acid cycle and oxidative phosphorylation (OXPHOS), the final steps of ATP synthesis via cellular respiration. Each mitochondrion contains its own genome; in vertebrates, this is a small, circular DNA molecule that encodes 13 subunits of the multiprotein OXPHOS electron transport complexes. Vertebrate lineages vary dramatically in metabolic rates; thus, functional constraints on mitochondrial-encoded proteins likely differ, potentially impacting mitochondrial genome evolution. Here, we examine mitochondrial genome evolution in salamanders, which have the lowest metabolic requirements among tetrapods. We show that salamanders experience weaker purifying selection on protein-coding sequences than do frogs, a comparable amphibian clade with higher metabolic rates. In contrast, we find no evidence for weaker selection against mitochondrial genome expansion in salamanders. Together, these results suggest that different aspects of mitochondrial genome evolution (i.e., nucleotide substitution, accumulation of noncoding sequences) are differently affected by metabolic variation across tetrapod lineages.

  14. Metabolic rates and biochemical compositions of Apostichopus japonicus (Selenka) tissue during periods of inactivity

    NASA Astrophysics Data System (ADS)

    Bao, Jie; Dong, Shuanglin; Tian, Xiangli; Wang, Fang; Gao, Qinfeng; Dong, Yunwei

    2010-03-01

    Estivation, hibernation, and starvation are indispensable inactive states of sea cucumbers Apostichopus japonicus in nature and in culture ponds. Generally, temperature is the principal factor that induces estivation or hibernation in the sea cucumber. The present study provided insight into the physiological adaptations of A. japonicus during the three types of inactivity (hibernation, estivation, and starvation) by measuring the oxygen consumption rates ( Vo2) and biochemical compositions under laboratory conditions of low (3°C), normal (17°C) and high (24°C) temperature. The results show that the characteristics of A. japonicus in dormancy (hibernation and estivation) states were quite different from higher animals, such as fishes, amphibians, reptiles, and mammals, but more closely resembled a semi-dormant state. It was observed that the shift in the A. japonicus physiological state from normal to dormancy was a chronic rather than acute process, indicated by the gradual depression of metabolic rate. While metabolic rates declined 44.9% for the estivation group and 71.7% for the hibernation group, relative to initial rates, during the 36 d culture period, metabolic rates were not maintained at constant levels during these states. The metabolic depression processes for sea cucumbers in hibernation and estivation appeared to be a passive and an active metabolic suppression, respectively. In contrast, the metabolic rates (128.90±11.70 μg/g h) of estivating sea cucumbers were notably higher (107.85±6.31 μg/g h) than in starving sea cucumbers at 17°C, which indicated that the dormancy mechanism here, as a physiological inhibition, was not as efficient as in higher animals. Finally, the principle metabolic substrate or energy source of sea cucumbers in hibernation was lipid, whereas in estivation they mainly consumed protein in the early times and both protein and lipid thereafter.

  15. Hygienic quality of artificial greywater subjected to aerobic treatment: a comparison of three filter media at increasing organic loading rates

    PubMed Central

    Lalander, Cecilia; Dalahmeh, Sahar; Jönsson, Håkan; Vinnerås, Björn

    2013-01-01

    With a growing world population, the lack of reliable water sources is becoming an increasing problem. Reusing greywater could alleviate this problem. When reusing greywater for crop irrigation it is paramount to ensure the removal of pathogenic organisms. This study compared the pathogen removal efficiency of pine bark and activated charcoal filters with that of conventional sand filters at three organic loading rates. The removal efficiency of Escherichia coli O157:H7 decreased drastically when the organic loading rate increased fivefold in the charcoal and sand filters, but increased by 2 log10 in the bark filters. The reduction in the virus model organism coliphage ΦX174 remained unchanged with increasing organic loading in the charcoal and sand filters, but increased by 2 log10 in the bark filters. Thus, bark was demonstrated to be the most promising material for greywater treatment in terms of pathogen removal. PMID:24527627

  16. Hygienic quality of artificial greywater subjected to aerobic treatment: a comparison of three filter media at increasing organic loading rates.

    PubMed

    Lalander, Cecilia; Dalahmeh, Sahar; Jönsson, Håkan; Vinnerås, Björn

    2013-01-01

    With a growing world population, the lack of reliable water sources is becoming an increasing problem. Reusing greywater could alleviate this problem. When reusing greywater for crop irrigation it is paramount to ensure the removal of pathogenic organisms. This study compared the pathogen removal efficiency of pine bark and activated charcoal filters with that of conventional sand filters at three organic loading rates. The removal efficiency of Escherichia coli O157:H7 decreased drastically when the organic loading rate increased fivefold in the charcoal and sand filters, but increased by 2 log10 in the bark filters. The reduction in the virus model organism coliphage phiX174 remained unchanged with increasing organic loading in the charcoal and sand filters, but increased by 2 log10 in the bark filters. Thus, bark was demonstrated to be the most promising material for greywater treatment in terms of pathogen removal.

  17. The application of a simplified method to map the aerobic acetate mineralization rates at the groundwater table of the Netherlands

    NASA Astrophysics Data System (ADS)

    Van Beelen, Patrick; Wouterse, Marja J.; Masselink, Niels J.; Spijker, Job; Mesman, Miranda

    2011-03-01

    A simplified method is used to assess the microbial activity of subsoils and soils across a broad geographic scale. Acetate was selected because it is a major intermediate in catabolic biochemical pathways. In order to get minimal disturbance, only a small amount of tritium labelled acetate and water is added to the subsoil material. After an incubation time, the subsoil material is separated from the water by centrifugation and the formed tritium labelled water is separated from the remaining acetate by evaporation. The data of 128 locations in the Netherlands were plotted in a soil map and were also compared with the depth, dry weight, electric conductivity, pH and nitrate concentration. The peat areas consisted of limed meadows with a high groundwater level whereas the sand areas often showed deeper groundwater levels and a lower pH. The subsoils at the groundwater table of the peat areas, which are in contact with soil air, showed a higher mineralization rate compared with the surface soils in our study. In contrast, the mineralization rate of the subsoil at the groundwater table of sandy soils showed on average a factor 30 lower rate. Nevertheless, the self purification capacity of the subsoil can be vital under weather conditions where the surface soil becomes less active.

  18. Age differences in intercorrelations between regional cerebral metabolic rates for glucose

    SciTech Connect

    Horwitz, B.; Duara, R.; Rapoport, S.I.

    1986-01-01

    Patterns of cerebral metabolic intercorrelations were compared in the resting state in 15 healthy young men (ages 20 to 32 years) and 15 healthy elderly men (ages 64 to 83 years). Controlling for whole-brain glucose metabolism, partial correlation coefficients were determined between pairs of regional cerebral metabolic rates for glucose determined by positron emission tomography using (18F)fluorodeoxyglucose and obtained in 59 brain regions. Compared with the young men, the elderly men had fewer statistically significant correlations, with the most notable reductions observed between the parietal lobe regions, and between the parietal and frontal lobe regions. These results suggest that cerebral functional interactions are reduced in healthy elderly men.

  19. Metabolic rate measurements comparing supine with upright upper-body exercises

    NASA Technical Reports Server (NTRS)

    Fortney, Suzanne M.; Greenisen, Michael C.; Loftin, Karin C.; Beene, Donya; Freeman-Perez, Sondra; Hnatt, Linda

    1993-01-01

    The ground-based study that tested the hypothesis that metabolic rates during supine and upright upper-body exercises are similar (mean value of 200 kcal/h) is presented. Six subjects each performed supine or upright exercise at three exercise stations, a hand-cycle ergometer, a rope-pull device, and a torque wrench. After a baseline measurement of the metabolic rate at rest, the metabolic rate was measured twice at each exercise station. The mean metabolic rates (kcal/h) during supine (n = 6) and upright control (n = 4) exercise stations were not significantly different except for the rope-pull station, 153.5 +/- 16.6 (supine) as compared to 247.0 +/- 21.7 (upright), p is less than 0.05. This difference may be due in part to an increased mechanical efficiency of supine exercises (15.0 +/- 0.7 percent) as compared to that of upright exercises (11.0 +/- 1.08 percent), p is less than 0.05. The net energy input was significantly smaller for the supine rope-pull exercise (64 +/- 18) as compared to upright (176 +/- 20). The relationship between best-rest exercises, metabolic rates, and the incidence of decompression sickness (DCS) should be examined to determine the true risk of DCS in spaceflight extravehicular activities.

  20. Metabolically Derived human ventilation rates: A revised approach based upon oxygen consumption rates (Final Report) 2009

    EPA Science Inventory

    The purpose of this report is to provide a revised approach for calculating an individual's ventilation rate directly from their oxygen consumption rate. This revised approach will be used to update the ventilation rate information in the Exposure Factors Handbook, which serve as...

  1. Influence of tacrolimus metabolism rate on BKV infection after kidney transplantation

    PubMed Central

    Thölking, Gerold; Schmidt, Christina; Koch, Raphael; Schuette-Nuetgen, Katharina; Pabst, Dirk; Wolters, Heiner; Kabar, Iyad; Hüsing, Anna; Pavenstädt, Hermann; Reuter, Stefan; Suwelack, Barbara

    2016-01-01

    Immunosuppression is the major risk factor for BK virus nephropathy (BKVN) after renal transplantation (RTx). As the individual tacrolimus (Tac) metabolism rate correlates with Tac side effects, we hypothesized that Tac metabolism might also influence the BKV infection risk. In this case-control study RTx patients with BK viremia within 4 years after RTx (BKV group) were compared with a BKV negative control group. The Tac metabolism rate expressed as the blood concentration normalized by the daily dose (C/D ratio) was applied to assess the Tac metabolism rate. BK viremia was detected in 86 patients after a median time of 6 (0–36) months after RTx. BKV positive patients showed lower Tac C/D ratios at 1, 3 and 6 months after RTx and were classified as fast Tac metabolizers. 8 of 86 patients with BK viremia had histologically proven BKN and a higher median maximum viral load than BKV patients without BKN (441,000 vs. 18,572 copies/mL). We conclude from our data that fast Tac metabolism (C/D ratio <1.05) is associated with BK viremia after RTx. Calculation of the Tac C/D ratio early after RTx, may assist transplant clinicians to identify patients at risk and to choose the optimal immunosuppressive regimen. PMID:27573493

  2. Temporal repeatability of metabolic rate and the effect of organ mass and enzyme activity on metabolism in European eel (Anguilla anguilla).

    PubMed

    Boldsen, Martin Maagaard; Norin, Tommy; Malte, Hans

    2013-05-01

    Intraspecific variation in metabolic rate of fish can be pronounced and have been linked to various fitness-related behavioural and physiological traits, but the underlying causes for this variation have received far less attention than the consequences of it. In the present study we investigated whether European eels (Anguilla anguilla) displayed temporal repeatability of body-mass-corrected (residual) metabolic rate over a two-month period and if variations in organ mass and enzyme activity between individual fish could be the cause for the observed variation in metabolic rate. Both standard metabolic rate (SMR; Pearson's r=0.743) and routine metabolic rate (RMR; r=0.496) were repeatable over the two-month period. Repeatability of RMR is an interesting finding as it indicates that the level of spontaneous activity in respirometer-confined fish is not random. Cumulative organ mass (liver, heart, spleen and intestine; mean 1.6% total body mass) was found to explain 38% of the variation in SMR (r=0.613) with the liver (one of the metabolically most active organs) being the driver for the correlation between organ mass and metabolic rate. No relationships were found for either liver citrate synthase or cytochrome oxidase activity and metabolic rate in the European eels. Reasons for, and contributions to, the observed variation in metabolic rate are discussed.

  3. Growth hormone transgenesis and polyploidy increase metabolic rate, alter the cardiorespiratory response and influence HSP expression in response to acute hypoxia in Atlantic salmon (Salmo salar) yolk-sac alevins.

    PubMed

    Polymeropoulos, Elias T; Plouffe, Debbie; LeBlanc, Sacha; Elliott, Nick G; Currie, Suzie; Frappell, Peter B

    2014-07-01

    Growth hormone (GH)-transgenic Atlantic salmon display accelerated growth rates compared with non-transgenics. GH-transgenic fish also display cardiorespiratory and metabolic modifications that accompany the increased growth rate. An elevated routine metabolic rate has been described for pre- and post-smolt GH-transgenic salmon that also display improvements in oxygen delivery to support the increased aerobic demand. The early ontogenic effects of GH transgenesis on the respiratory and cellular physiology of fish, especially during adverse environmental conditions, and the effect of polyploidy are unclear. Here, we investigated the effects of GH transgenesis and polyploidy on metabolic, heart and ventilation rates and heat shock protein (HSP) levels after exposure to acute hypoxia in post-hatch Atlantic salmon yolk-sac alevins. Metabolic rate decreased with decreasing partial pressures of oxygen in all genotypes. In normoxia, triploid transgenics displayed the highest mass-specific metabolic rates in comparison to diploid transgenics and non-transgenic triploids, which, in contrast, had higher rates than diploid non-transgenics. In hypoxia, we observed a lower mass-specific metabolic rate in diploid non-transgenics compared with all other genotypes. However, no evidence for improved O2 uptake through heart or ventilation rate was found. Heart rate decreased in diploid non-transgenics while ventilation rate decreased in both diploid non-transgenics and triploid transgenics in severe hypoxia. Regardless of genotype or treatment, inducible HSP70 was not expressed in alevins. Following hypoxia, the constitutive isoform of HSP70, HSC70, decreased in transgenics and HSP90 expression decreased in all genotypes. These data suggest that physiological changes through GH transgenesis and polyploidy are manifested during early ontogeny in Atlantic salmon.

  4. 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 (rate per kg than women with higher V. Similarly urea generation rate normalized to fat-free mass was significantly greater in small women than in all others (significant only in comparison to larger men). Exercise-related 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.

  5. Negative relationships between population density and metabolic rates are not general.

    PubMed

    Yashchenko, Varvara; Fossen, Erlend Ignacio; Kielland, Øystein Nordeide; Einum, Sigurd

    2016-07-01

    Population density has recently been suggested to be an important factor influencing metabolic rates and to represent an important 'third axis' explaining variation beyond that explained by body mass and temperature. In situations where population density influences food consumption, the immediate effect on metabolism acting through specific dynamic action (SDA), and downregulation due to fasting over longer periods, is well understood. However, according to a recent review, previous studies suggest a more general effect of population density per se, even in the absence of such effects. It has been hypothesized that this results from animals performing anticipatory responses (i.e. reduced activity) to expected declines in food availability. Here, we test the generality of this finding by measuring density effects on metabolic rates in 10 clones from two different species of the zooplankton Daphnia (Daphnia pulex Leydig and D. magna Straus). Using fluorescence-based respirometry, we obtain high-precision measures of metabolism. We also identify additional studies on this topic that were not included in the previous review, compare the results and evaluate the potential for measurement bias in all previous studies. We demonstrate significant variation in mass-specific metabolism among clones within both species. However, we find no evidence for a negative relationship between population density and mass-specific metabolism. The previously reported pattern also disappeared when we extended the set of studies analysed. We discuss potential reasons for the discrepancy among studies, including two main sources of potential bias (microbial respiration and declining oxygen consumption due to reduced oxygen availability). Only one of the previous studies gives sufficient information to conclude the absence of such biases, and consistent with our results, no effect of density on metabolism was found. We conclude that population density per se does not have a general effect

  6. Measuring Rates of Herbicide Metabolism in Dicot Weeds with an Excised Leaf Assay.

    PubMed

    Ma, Rong; Skelton, Joshua J; Riechers, Dean E

    2015-09-07

    In order to isolate and accurately determine rates of herbicide metabolism in an obligate-outcrossing dicot weed, waterhemp (Amaranthus tuberculatus), we developed an excised leaf assay combined with a vegetative cloning strategy to normalize herbicide uptake and remove translocation as contributing factors in herbicide-resistant (R) and -sensitive (S) waterhemp populations. Biokinetic analyses of organic pesticides in plants typically include the determination of uptake, translocation (delivery to the target site), metabolic fate, and interactions with the target site. Herbicide metabolism is an important parameter to measure in herbicide-resistant weeds and herbicide-tolerant crops, and is typically accomplished with whole-plant tests using radiolabeled herbicides. However, one difficulty with interpreting biokinetic parameters derived from whole-plant methods is that translocation is often affected by rates of herbicide metabolism, since polar metabolites are usually not mobile within the plant following herbicide detoxification reactions. Advantages of the protocol described in this manuscript include reproducible, accurate, and rapid determination of herbicide degradation rates in R and S populations, a substantial decrease in the amount of radiolabeled herbicide consumed, a large reduction in radiolabeled plant materials requiring further handling and disposal, and the ability to perform radiolabeled herbicide experiments in the lab or growth chamber instead of a greenhouse. As herbicide resistance continues to develop and spread in dicot weed populations worldwide, the excised leaf assay method developed and described herein will provide an invaluable technique for investigating non-target site-based resistance due to enhanced rates of herbicide metabolism and detoxification.

  7. Circannual rhythm of resting metabolic rate of a small Afrotropical bird.

    PubMed

    Thompson, Lindy J; Brown, Mark; Downs, Colleen T

    2015-07-01

    Seasonal variation in avian metabolic rate is well established in Holarctic and temperate species, while trends in Afrotropical species are relatively poorly understood. Furthermore, given the paucity of data on circannual rhythm in avian metabolism, it is not known whether seasonal measurements made in summer and winter correspond with annual peaks and troughs in avian metabolic rate. Thus, we investigated how mean body mass, resting metabolic rate (RMR) and evaporative water loss (EWL) of a small Afrotropical bird, the Cape white-eye (Zosterops virens), changed monthly over the course of a year at 20°C and 25°C. Mean body mass was 12.2±1.0g throughout the study period. However, both EWL and RMR varied monthly, and peaks and troughs in RMR occurred in March and October respectively, which did not correspond to peaks and troughs in mean monthly outdoor ambient temperatures. These results suggest that measuring RMR at the height of summer and winter may underestimate the flexibility of which birds are capable in terms of their metabolic rate. We encourage further studies on this topic, to establish whether the lag between environmental temperature and RMR is consistent in other species.

  8. Flexibility in metabolic rate and activity level determines individual variation in overwinter performance.

    PubMed

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

    2016-11-01

    Energy stores are essential for the overwinter survival of many temperate and polar animals, but individuals within a species often differ in how quickly they deplete their reserves. These disparities in overwinter performance may be explained by differences in their physiological and behavioral flexibility in response to food scarcity. However, little is known about whether individuals exhibit correlated or independent changes in these traits, and how these phenotypic changes collectively affect their winter energy use. We examined individual flexibility in both standard metabolic rate and activity level in response to food scarcity and their combined consequences for depletion of lipid stores among overwintering brown trout (Salmo trutta). Metabolism and activity tended to decrease, yet individuals exhibited striking differences in their physiological and behavioral flexibility. The rate of lipid depletion was negatively related to decreases in both metabolic and activity rates, with the smallest lipid loss over the simulated winter period occurring in individuals that had the greatest reductions in metabolism and/or activity. However, changes in metabolism and activity were negatively correlated; those individuals that decreased their SMR to a greater extent tended to increase their activity rates, and vice versa, suggesting among-individual variation in strategies for coping with food scarcity.

  9. Selected contribution: long-lived Drosophila melanogaster lines exhibit normal metabolic rates.

    PubMed

    van Voorhies, Wayne A; Khazaeli, Aziz A; Curtsinger, James W

    2003-12-01

    The use of model organisms, such as Drosophila melanogaster, provides a powerful method for studying mechanisms of aging. Here we report on a large set of recombinant inbred (RI) D. melanogaster lines that exhibit approximately a fivefold range of average adult longevities. Understanding the factors responsible for the differences in longevity, particularly the characteristics of the longest-lived lines, can provide fundamental insights into the mechanistic correlates of aging. In ectothermic organisms, longevity is often inversely correlated with metabolic rate, suggesting the a priori hypothesis that long-lived lines will have low resting metabolic rates. We conducted approximately 6000 measurements of CO2 production in individual male flies aged 5, 16, 29, and 47 days postemergence and simultaneously measured the weight of individual flies and life spans in populations of each line. Even though there was a wide range of longevities, there was no evidence of an inverse relationship between the variables. The increased longevity of long-lived lines is not mediated through reduction of metabolic activity. In Drosophila, it is possible to both maintain a normal metabolic rate and achieve long life. These results are evaluated in the context of 100 years of research on the relationship between metabolic rate and life span.

  10. Genetic architecture of metabolic rate: environment specific epistasis between mitochondrial and nuclear genes in an insect.

    PubMed

    Arnqvist, Göran; Dowling, Damian K; Eady, Paul; Gay, Laurene; Tregenza, Tom; Tuda, Midori; Hosken, David J

    2010-12-01

    The extent to which mitochondrial DNA (mtDNA) variation is involved in adaptive evolutionary change is currently being reevaluated. In particular, emerging evidence suggests that mtDNA genes coevolve with the nuclear genes with which they interact to form the energy producing enzyme complexes in the mitochondria. This suggests that intergenomic epistasis between mitochondrial and nuclear genes may affect whole-organism metabolic phenotypes. Here, we use crossed combinations of mitochondrial and nuclear lineages of the seed beetle Callosobruchus maculatus and assay metabolic rate under two different temperature regimes. Metabolic rate was affected by an interaction between the mitochondrial and nuclear lineages and the temperature regime. Sequence data suggests that mitochondrial genetic variation has a role in determining the outcome of this interaction. Our genetic dissection of metabolic rate reveals a high level of complexity, encompassing genetic interactions over two genomes, and genotype × genotype × environment interactions. The evolutionary implications of these results are twofold. First, because metabolic rate is at the root of life histories, our results provide insights into the complexity of life-history evolution in general, and thermal adaptation in particular. Second, our results suggest a mechanism that could contribute to the maintenance of nonneutral mtDNA polymorphism.

  11. Effect of pH on the metabolic flux of Klebsiella oxytoca producing 2,3-butanediol in continuous cultures at different dilution rates.

    PubMed

    Park, Changhun; Lu, Mingshou; Yun, Seokhun; Park, Kyungmoon; Lee, Jinwon

    2013-06-01

    The efficiency of the bioconversion process and the achievable end-product concentration decides the economic feasibility of microbial 2,3-butanediol (2,3-BDO) production. In 2,3-BDO production, optimization of culture condition is required for cell growth and metabolism. Also, the pH is an important factor that influences microbial performance. For different microorganisms and substrates, it has been shown that the distribution of the metabolites in 2,3-BDO fermentation is greatly affected by pH, and the optimum pH for 2,3-BDO production seems dependently linked to the particular strain and the substrate employed. Quantification analysis of intracellular metabolites and metabolic flux analysis (MFA) were used to investigate the effect of pH on the Klebsiella oxytoca producing 2,3-BDO and other organic acids. The main objectives of MFA are the estimation of intracellular metabolic fluxes and the identification of rate-limiting step and the key enzymes. This study was conducted under continuous aerobic conditions at different dilution rates (0.1, 0.2, and 0.3 h(-1)) and different pH values (pH 5.5 and 7.0) for the steady-state experimental data. In order to obtain the flux distribution, the extracellular specific rates were calculated from the experimental data using the metabolic network model of K. oxytoca. Intracellular metabolite concentration profiles were generated using ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry.

  12. Flight Modes in Migrating European Bee-Eaters: Heart Rate May Indicate Low Metabolic Rate during Soaring and Gliding

    PubMed Central

    Sapir, Nir; Wikelski, Martin; McCue, Marshall D.; Pinshow, Berry; Nathan, Ran

    2010-01-01

    Background Many avian species soar and glide over land. Evidence from large birds (mb>0.9 kg) suggests that soaring-gliding is considerably cheaper in terms of energy than flapping flight, and costs about two to three times the basal metabolic rate (BMR). Yet, soaring-gliding is considered unfavorable for small birds because migration speed in small birds during soaring-gliding is believed to be lower than that of flapping flight. Nevertheless, several small bird species routinely soar and glide. Methodology/Principal Findings To estimate the energetic cost of soaring-gliding flight in small birds, we measured heart beat frequencies of free-ranging migrating European bee-eaters (Merops apiaster, mb∼55 g) using radio telemetry, and established the relationship between heart beat frequency and metabolic rate (by indirect calorimetry) in the laboratory. Heart beat frequency during sustained soaring-gliding was 2.2 to 2.5 times lower than during flapping flight, but similar to, and not significantly different from, that measured in resting birds. We estimated that soaring-gliding metabolic rate of European bee-eaters is about twice their basal metabolic rate (BMR), which is similar to the value estimated in the black-browed albatross Thalassarche (previously Diomedea) melanophrys, mb∼4 kg). We found that soaring-gliding migration speed is not significantly different from flapping migration speed. Conclusions/Significance We found no evidence that soaring-gliding speed is slower than flapping flight in bee-eaters, contradicting earlier estimates that implied a migration speed penalty for using soaring-gliding rather than flapping flight. Moreover, we suggest that small birds soar and glide during migration, breeding, dispersal, and other stages in their annual cycle because it may entail a low energy cost of transport. We propose that the energy cost of soaring-gliding may be proportional to BMR regardless of bird size, as theoretically deduced by earlier studies

  13. Thyroid hormones correlate with field metabolic rate in ponies, Equus ferus caballus.

    PubMed

    Brinkmann, Lea; Gerken, Martina; Hambly, Catherine; Speakman, John R; Riek, Alexander

    2016-08-15

    During winter, free-living herbivores are often exposed to reduced energy supply at the same time that energy needs for thermoregulation increase. Several wild herbivores as well as robust horse breeds reduce their metabolism during times of low ambient temperature and food shortage. Thyroid hormones (THs) affect metabolic intensity and a positive effect of THs on basal metabolic rate (BMR) has been demonstrated in mammals and birds. As BMR and field metabolic rate (FMR) are often assumed to be intrinsically linked, THs may represent a reliable indicator for FMR. To test this hypothesis, 10 Shetland pony mares were kept under semi-extensive central European conditions. During the winter season, one group was fed 60% and one group 100% of their maintenance energy requirements. We measured FMR, locomotor activity, resting heart rate and TH levels in summer and winter. FMR, locomotor activity, resting heart rate and total T3 concentrations decreased substantially in winter compared with summer, whereas total T4 increased. Food restriction led to a reduced FMR and resting heart rate, while THs and locomotor activity were not affected. Across both seasons, FMR, resting heart rate and locomotor activity were positively correlated with total T3 but negatively and more weakly correlated with total T4.

  14. The effect of metabolic depression on proton leak rate in mitochondria from hibernating frogs.

    PubMed

    St-Pierre, J; Brand, M D; Boutilier, R G

    2000-05-01

    Futile cycling of protons across the mitochondrial inner membrane accounts for 20 % or more of the total standard metabolic rate of a rat. Approximately 15 % of this total is due to proton leakage inside the skeletal muscle alone. This study examined whether the rate of proton leak is down-regulated as a part of a coordinated response to energy conservation during metabolic depression in cold-submerged frogs. We compared the proton leak rate of skeletal muscle mitochondria isolated from frogs at different stages of hibernation (control, 1 month and 4 months of submergence in normoxia and hypoxia). The kinetics of mitochondrial proton leak rate was unaltered throughout normoxic and hypoxic submergence. The state 4 respiration rates did not differ between control animals and frogs hibernating in normoxia. In contrast, the state 4 respiration rates obtained from frogs submerged in hypoxic water for 4 months were half those of control animals. This 50 % reduction in respiration rate in hypoxic hibernation was due to a reduction in electron transport chain activity and consequent decrease in mitochondrial membrane potential. We conclude that proton leak rate is reduced during metabolic depression as a secondary result of a decrease in electron transport chain activity, but that the proton conductance is unchanged. In addition, we show that the rate of proton leakage and the activity of the electron transport chain are lower in frogs than in rats, strengthening the observation that mitochondria from ectotherms have a lower proton conductance than mitochondria from endotherms.

  15. Seasonal variation of resting metabolic rate and body mass in free-living weasels Mustela nivalis.

    PubMed

    Szafrańska, Paulina A; Zub, Karol; Konarzewski, Marek

    2013-01-01

    Metabolic rates and body mass of mammals vary seasonally along with ambient temperatures and food availability. At the population level, seasonal changes in metabolic rate and mass can be due to selective mortality or emigration of individuals whose metabolic rate or mass differs from the average for the population. Alternatively, the metabolic rates of individuals can change seasonally, such that the population average increases or decreases due to shifts in the physiology of the overall population. The latter implies that individuals respond in a similar manner to changing seasonal conditions. We studied seasonal changes in body mass (BM) and resting metabolic rate (RMR) in free-ranging male weasels (Mustela nivalis) to test the consistency of these traits in individuals caught in different seasons of the year. At the population level, BM was remarkably stable across the seasons (F(3, 124)=0.25, P=0.9). In contrast, BM- corrected RMR varied significantly between seasons and was the lowest in winter (F(3, 135)=9.13, P<0.0001). We demonstrated that individual weasels were consistent in how their BM and RMR deviated from the seasonal means for the population (intraclass correlation, τ=0.78 and 0.33, respectively). This variation among individuals explained ~76% and 27% of the total variation of BM and basal metabolic rate, respectively. Hence, the relatively constant BM at the population level across seasons is due to a relative constancy of BM in individuals. Our study is one of relatively few research projects that demonstrate that seasonal changes in RMR observed in the wild population are in part due to a consistency in individual responses to changing environmental conditions.

  16. The Relationship of Sleep with Temperature and Metabolic Rate in a Hibernating Primate

    PubMed Central

    Krystal, Andrew D.; Schopler, Bobby; Kobbe, Susanne; Williams, Cathy; Rakatondrainibe, Hajanirina; Yoder, Anne D.; Klopfer, Peter

    2013-01-01

    Study Objectives It has long been suspected that sleep is important for regulating body temperature and metabolic-rate. Hibernation, a state of acute hypothermia and reduced metabolic-rate, offers a promising system for investigating those relationships. Prior studies in hibernating ground squirrels report that, although sleep occurs during hibernation, it manifests only as non-REM sleep, and only at relatively high temperatures. In our study, we report data on sleep during hibernation in a lemuriform primate, Cheirogaleus medius. As the only primate known to experience prolonged periods of hibernation and as an inhabitant of more temperate climates than ground squirrels, this animal serves as an alternative model for exploring sleep temperature/metabolism relationships that may be uniquely relevant to understanding human physiology. Measurements and Results We find that during hibernation, non-REM sleep is absent in Cheirogaleus. Rather, periods of REM sleep occur during periods of relatively high ambient temperature, a pattern opposite of that observed in ground squirrels. Like ground squirrels, however, EEG is marked by ultra-low voltage activity at relatively low metabolic-rates. Conclusions These findings confirm a sleep-temperature/metabolism link, though they also suggest that the relationship of sleep stage with temperature/metabolism is flexible and may differ across species or mammalian orders. The absence of non-REM sleep suggests that during hibernation in Cheirogaleus, like in the ground squirrel, the otherwise universal non-REM sleep homeostatic response is greatly curtailed or absent. Lastly, ultra-low voltage EEG appears to be a cross-species marker for extremely low metabolic-rate, and, as such, may be an attractive target for research on hibernation induction. PMID:24023713

  17. Does the metabolic rate-flight speed relationship vary among geometrically similar birds of different mass?

    PubMed

    Bundle, Matthew W; Hansen, Kacia S; Dial, Kenneth P

    2007-03-01

    Based on aerodynamic considerations, the energy use-flight speed relationship of all airborne animals and aircraft should be U-shaped. However, measures of the metabolic rate-flight speed relationship in birds have been available since Tucker's pioneering experiments with budgerigars nearly forty years ago, but this classic work remains the only study to have found a clearly U-shaped metabolic power curve. The available data suggests that the energetic requirements for flight within this species are unique, yet the metabolic power curve of the budgerigar is widely considered representative of birds in general. Given these conflicting results and the observation that the budgerigar's mass is less than 50% of the next smallest species to have been studied, we asked whether large and small birds have metabolic power curves of different shapes. To address this question we measured the rates of oxygen uptake and wingbeat kinematics in budgerigars and cockatiels flying within a variable-speed wind tunnel. These species are close phylogenetic relatives, have similar flight styles, wingbeat kinematics, and are geometrically similar but have body masses that differ by a factor of two. In contrast to our expectations, we found the metabolic rate-flight speed relationship of both species to be acutely U-shaped. We also found that neither budgerigars nor cockatiels used their normal intermittent flight style while wearing a respirometric mask. We conclude that species size differences alone do not explain the previously unique metabolic power curve of the budgerigar; however, due to the absence of comparable data we cannot evaluate whether the mask-related kinematic response we document influences the metabolic rate-flight speed relationship of these parrots, or whether the energetics of flight differ between this and other avian clades.

  18. Inner retinal metabolic rate of oxygen by oxygen tension and blood flow imaging in rat.

    PubMed

    Wanek, Justin; Teng, Pang-Yu; Albers, John; Blair, Norman P; Shahidi, Mahnaz

    2011-09-01

    The metabolic function of inner retinal cells relies on the availability of nutrients and oxygen that are supplied by the retinal circulation. Assessment of retinal tissue vitality and function requires knowledge of both the rate of oxygen delivery and consumption. The purpose of the current study is to report a novel technique for assessment of the inner retinal metabolic rate of oxygen (MO(2)) by combined measurements of retinal blood flow and vascular oxygen tension (PO(2)) in rat. The application of this technology has the potential to broaden knowledge of retinal oxygen dynamics and advance understanding of disease pathophysiology.

  19. Reduced swim performance and aerobic capacity in adult zebrafish exposed to waterborne selenite.

    PubMed

    Massé, Anita J; Thomas, Jith K; Janz, David M

    2013-04-01

    Although dietary exposure of adult fish to organoselenium in contaminated aquatic ecosystems has been reported to bioaccumulate and cause larval deformities in offspring, subtle physiological effects produced through low level waterborne selenium exposure in fish such as swim performance and aerobic capacity have not been investigated. To evaluate potential effects of selenite on these responses, adult zebrafish (Danio rerio) were exposed to nominal aqueous concentrations of 0, 10 or 100 μg/L sodium selenite for 14 days. Upon completion of the exposure period, fish underwent two successive swim trials in a swim tunnel respirometer to determine critical swim speed (Ucrit), oxygen consumption (MO2), standard and active metabolic rates, aerobic scope (AS) and cost of transport (COT) followed by analysis of whole body triglyceride and glycogen concentrations. Selenite exposure had a significant negative effect on Ucrit and aerobic capacity. Active metabolic rates and AS significantly decreased in both selenite exposure groups after the second swim trial. No significant effect was observed in MO2, standard metabolic rate, COT, triglyceride and glycogen levels, or condition factor between groups. These results suggest that aqueous selenite exposure at environmentally relevant concentrations produces adverse effects on aerobic capacity that can diminish endurance and maximum swim speeds, which may lower fish survivability.

  20. 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.

  1. Minimal metabolic rate, what it is, its usefulness, and its relationship to the evolution of endothermy: a brief synopsis.

    PubMed

    Frappell, P B; Butler, P J

    2004-01-01

    Minimal metabolic rate represents the minimal cost of living and appears to have the same relative composition of adenosine triphosphate processes in all organisms. Minimal metabolic rate is influenced by temperature and defines the standard metabolic rate (SMR) of animals. Animals that achieve SMR only for a given temperature are strictly ectothermic. Endotherms, on the other hand, are characterized by leakier membranes and an associated increase in cellular metabolism for a given temperature. The increase in cellular metabolism is coupled with an increase in heat production (i.e., obligatory thermogenesis) that, together with SMR, defines the basal metabolic rate of an endotherm. Consideration of minimal metabolic rate must take into account ecological and physiological processes, environmental influences, evolutionary arguments, and body size.

  2. Body metabolic rate and electromyographic activities of antigravitational muscles in supine and standing postures.

    PubMed

    Rubini, Alessandro; Paoli, Antonio; Parmagnani, Andrea

    2012-06-01

    We measured metabolic (oxygen uptake, carbon dioxide production, respiratory ratio), cardio-circulatory (heart rate, systolic and diastolic arterial blood pressure, rate-pressure product, an index of myocardial oxygen consumption calculated by multiplying heart rate by systolic pressure) and electromyographic (integrated electromyographic activities of two antigravitational muscles of the lower limb, soleus and gastrocnemius) variables on 12 young healthy subjects in supine and standing positions at rest. We found statistically significant increments of oxygen uptake, carbon dioxide production, heart rate and integrated electromyographic activities in standing versus supine position. Rate-pressure product increased but not significantly, and no other significant changes were detected. We conclude that postural changes influence metabolic rate, antigravitational muscle reflex activities, and heart rate. A significant positive correlation was found between oxygen uptake and carbon dioxide production and integrated electromyographic activities of antigravitational muscles, while the same was not found for cardio-circulatory variables. These results suggest that the increased metabolic rate in standing position is, at least in part, due to antigravitational muscle tone.

  3. Winter Is Coming: Seasonal Variation in Resting Metabolic Rate of the European Badger (Meles meles)

    PubMed Central

    McClune, David W.; Kostka, Berit; Delahay, Richard J.; Montgomery, W. Ian; Marks, Nikki J.; Scantlebury, David M.

    2015-01-01

    Resting metabolic rate (RMR) is a measure of the minimum energy requirements of an animal at rest, and can give an indication of the costs of somatic maintenance. We measured RMR of free-ranging European badgers (Meles meles) to determine whether differences were related to sex, age and season. Badgers were captured in live-traps and placed individually within a metabolic chamber maintained at 20 ± 1°C. Resting metabolic rate was determined using an open-circuit respirometry system. Season was significantly correlated with RMR, but no effects of age or sex were detected. Summer RMR values were significantly higher than winter values (mass-adjusted mean ± standard error: 2366 ± 70 kJ⋅d−1; 1845 ± 109 kJ⋅d−1, respectively), with the percentage difference being 24.7%. While under the influence of anaesthesia, RMR was estimated to be 25.5% lower than the combined average value before administration, and after recovery from anaesthesia. Resting metabolic rate during the autumn and winter was not significantly different to allometric predictions of basal metabolic rate for mustelid species weighing 1 kg or greater, but badgers measured in the summer had values that were higher than predicted. Results suggest that a seasonal reduction in RMR coincides with apparent reductions in physical activity and body temperature as part of the overwintering strategy (‘winter lethargy’) in badgers. This study contributes to an expanding dataset on the ecophysiology of medium-sized carnivores, and emphasises the importance of considering season when making predictions of metabolic rate. PMID:26352150

  4. Increasing metabolic rate despite declining body weight in an adult parasitoid wasp.

    PubMed

    Casas, Jérôme; Body, Mélanie; Gutzwiller, Florence; Giron, David; Lazzari, Claudio R; Pincebourde, Sylvain; Richard, Romain; Llandres, Ana L

    2015-08-01

    Metabolic rate is a positive function of body weight, a rule valid for most organisms and the basis of several theories of metabolic ecology. For adult insects, however, the diversity of relationships between body mass and respiration remains unexplained. The aim of this study is to relate the respiratory metabolism of a parasitoid with body weight and foraging activity. We compared the metabolic rate of groups of starving and host-fed females of the parasitoid Eupelmus vuilleti recorded with respirometry for 7days, corresponding to the mean lifetime of starving females and over half of the lifetime of foraging females. The dynamics of carbohydrate, lipid and protein in the body of foraging females were quantified with biochemical techniques. Body mass and all body nutrients declined sharply from the first day onwards. By contrast, the CO2 produced and the O2 consumed increased steadily. Starving females showed the opposite trend, identifying foraging as the reason for the respiration increase of feeding females. Two complementary physiological processes explain the unexpected relationship between increasing metabolic rate and declining body weight. First, host hemolymph is a highly unbalanced food, and the excess nutrients (protein and carbohydrate) need to be voided, partially through excretion and partially through respiration. Second, a foraging young female produces eggs at an increasing rate during the first half of its lifetime, a process that also increases respiration. We posit that the time-varying metabolic rate contributions of the feeding and reproductive processes supplements the contribution of the structural mass and lead to the observed trend. We extend our explanations to other insect groups and discuss the potential for unification using Dynamic Energy Budget theory.

  5. Winter Is Coming: Seasonal Variation in Resting Metabolic Rate of the European Badger (Meles meles).

    PubMed

    McClune, David W; Kostka, Berit; Delahay, Richard J; Montgomery, W Ian; Marks, Nikki J; Scantlebury, David M

    2015-01-01

    Resting metabolic rate (RMR) is a measure of the minimum energy requirements of an animal at rest, and can give an indication of the costs of somatic maintenance. We measured RMR of free-ranging European badgers (Meles meles) to determine whether differences were related to sex, age and season. Badgers were captured in live-traps and placed individually within a metabolic chamber maintained at 20 ± 1°C. Resting metabolic rate was determined using an open-circuit respirometry system. Season was significantly correlated with RMR, but no effects of age or sex were detected. Summer RMR values were significantly higher than winter values (mass-adjusted mean ± standard error: 2366 ± 70 kJ⋅d(-1); 1845 ± 109 kJ⋅d(-1), respectively), with the percentage difference being 24.7%. While under the influence of anaesthesia, RMR was estimated to be 25.5% lower than the combined average value before administration, and after recovery from anaesthesia. Resting metabolic rate during the autumn and winter was not significantly different to allometric predictions of basal metabolic rate for mustelid species weighing 1 kg or greater, but badgers measured in the summer had values that were higher than predicted. Results suggest that a seasonal reduction in RMR coincides with apparent reductions in physical activity and body temperature as part of the overwintering strategy ('winter lethargy') in badgers. This study contributes to an expanding dataset on the ecophysiology of medium-sized carnivores, and emphasises the importance of considering season when making predictions of metabolic rate.

  6. Fixed metabolic costs for highly variable rates of protein synthesis in sea urchin embryos and larvae.

    PubMed

    Pace, Douglas A; Manahan, Donal T

    2006-01-01

    Defining the physiological mechanisms that set metabolic rates and the 'cost of living' is important for understanding the energy costs of development. Embryos and larvae of the sea urchin Lytechinus pictus (Verrill) were used to test hypotheses regarding differential costs of protein synthesis in animals differing in size, rates of protein synthesis, and physiological feeding states. For embryos, the rate of protein synthesis was 0.22+/-0.014 ng protein embryo(-1) h(-1) (mean +/- s.e.m.) and decreased in unfed larvae to an average rate of 0.05+/-0.001 ng protein larva(-1) h(-1). Fed larvae had rates of synthesis that were up to 194 times faster than unfed larvae (9.7+/-0.81 ng protein larva(-1) h(-1)). There was no significant difference, however, in the cost of protein synthesis between these larvae with very different physiological states. Furthermore, the cost of synthesis in the larval stages was also similar to costs measured for blastula and gastrula embryos of 8.4+/-0.99 J mg(-1) protein synthesized. The cost of protein synthesis was obtained using both direct ('inhibitor') and indirect ('correlative') measurements; both methods gave essentially identical results. Protein synthesis accounted for up to 54+/-8% of metabolic rate in embryos. Percent of metabolism accounted for by protein synthesis in larvae was dependent on their physiological feeding state, with protein synthesis accounting for 16+/-4% in unfed larvae and 75+/-11% in fed larvae. This regulation of metabolic rate was due to differential rates of synthesis for a fixed energy cost per unit mass of protein synthesized. The cost of synthesizing a unit of protein did not change with increasing rates of protein synthesis. We conclude that the cost of protein synthesis is independent of the rate of synthesis, developmental stage, size and physiological feeding state during sea urchin development.

  7. Acute hypoxia increases the cerebral metabolic rate – a magnetic resonance imaging study

    PubMed Central

    Lindberg, Ulrich; Aachmann-Andersen, Niels Jacob; Lisbjerg, Kristian; Christensen, Søren Just; Law, Ian; Rasmussen, Peter; Olsen, Niels V; Larsson, Henrik BW

    2015-01-01

    The aim of the present study was to examine changes in cerebral metabolism by magnetic resonance imaging of healthy subjects during inhalation of 10% O2 hypoxic air. Hypoxic exposure elevates cerebral perfusion, but its effect on energy metabolism has been less investigated. Magnetic resonance imaging techniques were used to measure global cerebral blood flow and the venous oxygen saturation in the sagittal sinus. Global cerebral metabolic rate of oxygen was quantified from cerebral blood flow and arteriovenous oxygen saturation difference. Concentrations of lactate, glutamate, N-acetylaspartate, creatine and phosphocreatine were measured in the visual cortex by magnetic resonance spectroscopy. Twenty-three young healthy males were scanned for 60 min during normoxia, followed by 40 min of breathing hypoxic air. Inhalation of hypoxic air resulted in an increase in cerebral blood flow of 15.5% (p = 0.058), and an increase in cerebral metabolic rate of oxygen of 8.5% (p = 0.035). Cerebral lactate concentration increased by 180.3% (p<10-6), glutamate increased by 4.7% (p<10-4) and creatine and phosphocreatine decreased by 15.2% (p<10-3). The N-acetylaspartate concentration was unchanged (p = 0.36). In conclusion, acute hypoxia in healthy subjects increased perfusion and metabolic rate, which could represent an increase in neuronal activity. We conclude that marked changes in brain homeostasis occur in the healthy human brain during exposure to acute hypoxia. PMID:26661163

  8. High Yolk Testosterone Transfer Is Associated with an Increased Female Metabolic Rate.

    PubMed

    Tschirren, Barbara; Ziegler, Ann-Kathrin; Canale, Cindy I; Okuliarová, Monika; Zeman, Michal; Giraudeau, Mathieu

    2016-01-01

    Yolk androgens of maternal origin are important mediators of prenatal maternal effects. Although in many species short-term benefits of exposure to high yolk androgen concentrations for the offspring have been observed, females differ substantially in the amount of androgens they transfer to their eggs. It suggests that costs for the offspring or the mother constrain the evolution of maternal hormone transfer. However, to date, the nature of these costs remains poorly understood. Unlike most previous work that focused on potential costs for the offspring, we here investigated whether high yolk testosterone transfer is associated with metabolic costs (i.e., a higher metabolic rate) for the mother. We show that Japanese quail (Coturnix japonica) females that deposit higher testosterone concentrations into their eggs have a higher resting metabolic rate. Because a higher metabolic rate is often associated with a shorter life span, this relationship may explain the negative association between yolk testosterone transfer and female longevity observed in the wild. Our results suggest that metabolic costs for the mother can balance the short-term benefits of yolk testosterone exposure for the offspring, thereby contributing to the maintenance of variation in maternal yolk hormone transfer in natural populations.

  9. Slight chronic elevation of C-reactive protein is associated with lower aerobic fitness but does not impair meal-induced stimulation of muscle protein metabolism in healthy old men.

    PubMed

    Buffière, Caroline; Mariotti, François; Savary-Auzeloux, Isabelle; Migné, Carole; Meunier, Nathalie; Hercberg, Serge; Cano, Noel; Rémond, Didier; Duclos, Martine; Dardevet, Dominique

    2015-03-01

    Ageing impairs the muscle anabolic effect of food intake, which may explain muscle loss and an increased risk of sarcopenia. Ageing is also associated with low grade inflammation (LGI), which has been negatively correlated with muscle mass and strength. In rodents, the muscle anabolic resistance observed during ageing and sarcopenia has been ascribed to the development of the LGI. We aimed to investigate this relationship in humans. We studied protein metabolism and physical fitness in healthy elderly volunteers with slight chronic C-reactive protein. Two groups of healthy elderly volunteers were selected on the presence (or not) of a chronic, slight, elevation of CRP (Control: <1; CRP+: >2 mg l(-1) and <10 mg l(-1) , for 2 months). Body composition, short performance battery test, aerobic fitness and muscle strength were assessed. Whole body and muscle protein metabolism and the splanchnic extraction of amino acids were assessed using [(13) C]leucine and [(2) H]leucine infusion. The anabolic effect of food intake was measured by studying the volunteers both at the post-absorptive and post-prandial states. Slight chronic CRP elevation resulted in neither an alteration of whole body, nor skeletal muscle protein metabolism at both the post-absorptive and the post-prandial states. However, CRP+ presented a reduction of physical fitness, increased abdominal fat mass and post-prandial insulin resistance. Plasma cytokines (interleukin-1, interleukin-6, tumour necrosis factor α) and markers of endothelial inflammation (intercellular adhesion molecule, vascular cell adhesion molecule, selectins) were similar between groups. An isolated elevated CRP in healthy older population does not indicate an impaired skeletal muscle anabolism after food intake, nor an increased risk of skeletal muscle wasting. We propose that a broader picture of LGI (notably with elevated pro-inflammatory cytokines) is required to impact muscle metabolism and mass. However, an isolated chronic CRP

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

    PubMed Central

    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 for

  11. Thermoneutral zone and scaling of metabolic rate on body mass in small mammals

    NASA Technical Reports Server (NTRS)

    Pace, N.; Rahlmann, D. F.

    1983-01-01

    A 4-species animal model suitable for experimental study of the effect of change in gravitational loading on the scale relationship between metabolic rate and total body mass is used to study the effect of temperature on metabolic rate in six male animals, 8-10 months of age, of each of the four species in the ambient temperature range 20-36 C. The measurements taken permitted partitioning of total body heat output into sensible heat loss by radiation, conduction and convection, and into latent heat loss by evaporation of water from the body surface. It is shown that the condition of thermoneutrality is important for metabolic scale effect studies, and that the thermoneutral zone for the species considered here is a narrow one.

  12. Intra-Seasonal Flexibility in Avian Metabolic Performance Highlights the Uncoupling of Basal Metabolic Rate and Thermogenic Capacity

    PubMed Central

    Petit, Magali; Lewden, Agnès; Vézina, François

    2013-01-01

    Stochastic winter weather events are predicted to increase in occurrence and amplitude at northern latitudes and organisms are expected to cope through phenotypic flexibility. Small avian species wintering in these environments show acclimatization where basal metabolic rate (BMR) and maximal thermogenic capacity (MSUM) are typically elevated. However, little is known on intra-seasonal variation in metabolic performance and on how population trends truly reflect individual flexibility. Here we report intra-seasonal variation in metabolic parameters measured at the population and individual levels in black-capped chickadees (Poecileatricapillus). Results confirmed that population patterns indeed reflect flexibility at the individual level. They showed the expected increase in BMR (6%) and MSUM (34%) in winter relative to summer but also, and most importantly, that these parameters changed differently through time. BMR began its seasonal increase in November, while MSUM had already achieved more than 20% of its inter-seasonal increase by October, and declined to its starting level by March, while MSUM remained high. Although both parameters co-vary on a yearly scale, this mismatch in the timing of variation in winter BMR and MSUM likely reflects different constraints acting on different physiological components and therefore suggests a lack of functional link between these parameters. PMID:23840843

  13. Intra-seasonal flexibility in avian metabolic performance highlights the uncoupling of basal metabolic rate and thermogenic capacity.

    PubMed

    Petit, Magali; Lewden, Agnès; Vézina, François

    2013-01-01

    Stochastic winter weather events are predicted to increase in occurrence and amplitude at northern latitudes and organisms are expected to cope through phenotypic flexibility. Small avian species wintering in these environments show acclimatization where basal metabolic rate (BMR) and maximal thermogenic capacity (MSUM) are typically elevated. However, little is known on intra-seasonal variation in metabolic performance and on how population trends truly reflect individual flexibility. Here we report intra-seasonal variation in metabolic parameters measured at the population and individual levels in black-capped chickadees (Poecileatricapillus). Results confirmed that population patterns indeed reflect flexibility at the individual level. They showed the expected increase in BMR (6%) and MSUM (34%) in winter relative to summer but also, and most importantly, that these parameters changed differently through time. BMR began its seasonal increase in November, while MSUM had already achieved more than 20% of its inter-seasonal increase by October, and declined to its starting level by March, while MSUM remained high. Although both parameters co-vary on a yearly scale, this mismatch in the timing of variation in winter BMR and MSUM likely reflects different constraints acting on different physiological components and therefore suggests a lack of functional link between these parameters.

  14. Metabolic cold adaptation contributes little to the interspecific variation in metabolic rates of 65 species of Drosophilidae.

    PubMed

    Messamah, Branwen; Kellermann, Vanessa; Malte, Hans; Loeschcke, Volker; Overgaard, Johannes

    2017-02-11

    Metabolic cold adaptation (MCA) is a controversial hypothesis suggesting that cold adapted species display an elevated metabolic rate (MR) compared to their warm climate relatives. Here we test for the presence of MCA in 65 species of drosophilid flies reared under common garden conditions. MR was measured at both 10 and 20°C for both sexes and data were analyzed in relation to the natural thermal environment of these species. We found considerable interspecific variation in MR ranging from 1.34 to 8.99µWmg(-1) at 10°C. As predicted by Bergmann's rule body mass of fly species correlated negatively with annual mean temperature (AMT), such that larger species were found in colder environments. Because larger flies have a higher total MR we found MR to vary with AMT, however, after inclusion of mass as a co-variate we found no significant effect of AMT. Furthermore, we did not find that thermal sensitivity of MR (Q10) varied with AMT. Based on this broad collection of species we therefore conclude that there is no adaptive pattern of metabolic cold adaptation within drosophilid species ranging from sub-arctic to tropical environments.

  15. Genome Size Evolution in Relation to Leaf Strategy and Metabolic Rates Revisited

    PubMed Central

    Beaulieu, Jeremy M.; Leitch, Ilia J.; Knight, Charles A.

    2007-01-01

    Background and Aims It has been proposed that having too much DNA may carry physiological consequences for plants. The strong correlation between DNA content, cell size and cell division rate could lead to predictable morphological variation in plants, including a negative relationship with leaf mass per unit area (LMA). In addition, the possible increased demand for resources in species with high DNA content may have downstream effects on maximal metabolic efficiency, including decreased metabolic rates. Methods Tests were made for genome size-dependent variation in LMA and metabolic rates (mass-based photosynthetic rate and dark respiration rate) using our own measurements and data from a plant functional trait database (Glopnet). These associations were tested using two metrics of genome size: bulk DNA amount (2C DNA) and monoploid genome size (1Cx DNA). The data were analysed using an evolutionary framework that included a regression analysis and independent contrasts using a phylogenetic tree with estimates of molecular diversification times. A contribution index for the LMA data set was also calculated to determine which divergences have the greatest influence on the relationship between genome size and LMA. Key Results and Conclusions A significant negative association was found between bulk DNA amount and LMA in angiosperms. This was primarily a result of influential divergences that may represent early shifts in growth form. However, divergences in bulk DNA amount were positively associated with divergences in LMA, suggesting that the relationship may be indirect and mediated through other traits directly related to genome size. There was a significant negative association between genome size and metabolic rates that was driven by a basal divergence between angiosperms and gymnosperms; no significant independent contrast results were found. Therefore, it is concluded that genome size-dependent constraints acting on metabolic efficiency may not exist within

  16. Basal and maximal metabolic rates differ in their response to rapid temperature change among avian species.

    PubMed

    Dubois, Karine; Hallot, Fanny; Vézina, François

    2016-10-01

    In birds, acclimation and acclimatization to temperature are associated with changes in basal (BMR), summit (Msum) and maximal (MMR) metabolic rates but little is known about the rate at which species adjust their phenotype to short-term temperature variations. Our aims were (1) to determine the pattern of metabolic adjustments following a rapid temperature change, (2) to determine whether performance varies at similar rates during exposure to warm or cold environments, and (3) to determine if BMR, Msum and MMR change at comparable rates during thermal acclimation. We measured these parameters in white-throated sparrows (Zonotrichia albicollis), black-capped chickadees (Poecile atricapillus), and snow buntings (Plectrophenax nivalis) after acclimation to 10 °C (day 0) and on the 4th and 8th days of acclimation to either -5 or 28 °C. Birds changed their metabolic phenotype within 8 days with patterns differing among species. Sparrows expressed the expected metabolic increases in the cold and decreases at thermoneutrality while performance in chickadees and buntings was not influenced by temperature but changed over time with inverse patterns. Our results suggest that BMR varies at comparable rates in warm and cold environments but changes faster than Msum and MMR, likely due to limitations in the rate of change in organ size and function. They also suggest that maximal metabolic capacity is lost faster in a warm environment than it is gained in a cold environment. With the expected increase in temperature stochasticity at northern latitudes, a loss of thermogenic capacity during warm winter days could, therefore, be detrimental if birds are slow to readjust their phenotype with the return of cold days.

  17. Exploration of Energy Metabolism in the Mouse Using Indirect Calorimetry: Measurement of Daily Energy Expenditure (DEE) and Basal Metabolic Rate (BMR).

    PubMed

    Meyer, Carola W; Reitmeir, Peter; Tschöp, Matthias H

    2015-09-01

    Current comprehensive mouse metabolic phenotyping involves studying energy balance in cohorts of mice via indirect calorimetry, which determines heat release from changes in respiratory air composition. Here, we describe the measurement of daily energy expenditure (DEE) and basal metabolic rate (BMR) in mice. These well-defined metabolic descriptors serve as meaningful first-line read-outs for metabolic phenotyping and should be reported when exploring energy expenditure in mice. For further guidance, the issue of appropriate sample sizes and the frequency of sampling of metabolic measurements is also discussed.

  18. Hypothermia reduces cerebral metabolic rate and cerebral blood flow in newborn pigs

    SciTech Connect

    Busija, D.W.; Leffler, C.W. )

    1987-10-01

    The authors examined effects of hypothermia on cerebral metabolic rate and cerebral blood flow in anesthetized, newborn pigs (1-4 days old). Cerebral blood flow (CBF) was determined with 15-{mu}m radioactive microspheres. Regional CBF ranged from 44 to 66 ml{center dot}min{sup {minus}1}{center dot}100 g{sup {minus}1}, and cerebral metabolic rate was 1.94 {plus minus} 0.23 ml O{sub 2}{center dot}100 g{sup {minus}1}{center dot}min{sup {minus}1} during normothermia (39{degree}C). Reduction of rectal temperature to 34-35{degree}C decreased CBF and cerebral metabolic rate 40-50%. In another group of piglets, they examined responsiveness of the cerebral circulation to arterial hypercapnia during hypothermia. Although absolute values for normocapnic and hypercapnic CBF were reduced by hypothermia and absolute values for normocapnic and hypercapnic cerebrovascular resistance were increased, the percentage changes from control in these variables during hypercapnia were similar during normothermia and hypothermia. In another group of animals that were maintained normothermic and exposed to two episodes of hypercapnia, there was no attenuation of cerebrovascular dilation during the second episode. They conclude that hypothermia reduces CBF secondarily to a decrease in cerebral metabolic rate and that percent dilator responsiveness to arterial hypercapnia is unaltered when body temperature is reduced.

  19. Alteration of basal metabolic rate in Holstein steers during fescue toxicosis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The results of this study indicate that consumption of E+ tall fescue by cattle results in a reduction in basal metabolic rate. Six ruminally cannulated steers were weight-matched and pair-fed during a two period crossover experiment. Each period consisted of two temperatures (22°C and 30°C). During...

  20. Attention Performance in Autism and Regional Brain Metabolic Rate Assessed by Positron Emission Tomography. Brief Report.

    ERIC Educational Resources Information Center

    Buchsbaum, M. S.; And Others

    1992-01-01

    This evaluation of seven high functioning adults with autism utilized positron emission tomography on a visual vigilance task. Although the subjects, as a group, did as well as normal controls on the task, there was a lack of normal hemispheric asymmetry in glucose metabolic rate. A heterogeneous etiology for autism is suggested to explain…

  1. Intelligence and Changes in Regional Cerebral Glucose Metabolic Rate Following Learning.

    ERIC Educational Resources Information Center

    Haier, Richard J.; And Others

    1992-01-01

    A study of eight normal right-handed men demonstrates widespread significant decreases in brain glucose metabolic rate (GMR) following learning a complex computer task, a computer game. Correlations between magnitude of GMR change and intelligence scores are also demonstrated. (SLD)

  2. Metabolic Syndrome and Short-Term Heart Rate Variability in Adults with Intellectual Disabilities

    ERIC Educational Resources Information Center

    Chang, Yaw-Wen; Lin, Jin-Ding; Chen, Wei-Liang; Yen, Chia-Feng; Loh, Ching-Hui; Fang, Wen-Hui; Wu, Li-Wei

    2012-01-01

    Metabolic syndrome (MetS) increases the risk of cardiovascular events. Heart rate variability (HRV) represents autonomic functioning, and reduced HRV significantly increases cardiovascular mortality. The aims of the present paper are to assess the prevalence of MetS in adults with intellectual disabilities (ID), the difference in short-term HRV…

  3. Within-population genetic effects of mtDNA on metabolic rate in Drosophila subobscura.

    PubMed

    Kurbalija Novičić, Z; Immonen, E; Jelić, M; AnÐelković, M; Stamenković-Radak, M; Arnqvist, G

    2015-02-01

    A growing body of research supports the view that within-species sequence variation in the mitochondrial genome (mtDNA) is functional, in the sense that it has important phenotypic effects. However, most of this empirical foundation is based on comparisons across populations, and few studies have addressed the functional significance of mtDNA polymorphism within populations. Here, using mitonuclear introgression lines, we assess differences in whole-organism metabolic rate of adult Drosophila subobscura fruit flies carrying either of three different sympatric mtDNA haplotypes. We document sizeable, up to 20%, differences in metabolic rate across these mtDNA haplotypes. Further, these mtDNA effects are to some extent sex specific. We found no significant nuclear or mitonuclear genetic effects on metabolic rate, consistent with a low degree of linkage disequilibrium between mitochondrial and nuclear genes within populations. The fact that mtDNA haplotype variation within a natural population affects metabolic rate, which is a key physiological trait with important effects on life-history traits, adds weight to the emergent view that mtDNA haplotype variation is under natural selection and it revitalizes the question as to what processes act to maintain functional mtDNA polymorphism within populations.

  4. AN IN SILICO INVESTIGATION OF THE ENANTIOSELECTIVE METABOLISM RATES OF TRIAZOLE FUGICIDES

    EPA Science Inventory

    The objective of this work is to use in silico methods such as ab initio quantum and classical force-field methods to explore and develop an understanding for the enantioselective metabolism rates experimentally observed in the triazole fungicide bromuconazole. This directed stud...

  5. Metabolic Rate: A Factor in Developing Obesity in Children with Down Syndrome?

    ERIC Educational Resources Information Center

    Chad, Karen; And Others

    1990-01-01

    Resting metabolic rate and its relation to selected anthropomorphic measures were determined in 11 male and 7 female noninstitutionalized children with Down Syndrome. Dietary analysis was performed to determine the children's nutritional status. Results have implications for the prevention and treatment of obesity in children with Down Syndrome.…

  6. Brain Size and Cerebral Glucose Metabolic Rate in Nonspecific Retardation and Down Syndrome.

    ERIC Educational Resources Information Center

    Haier, Richard J.; And Others

    1995-01-01

    Brain size and cerebral glucose metabolic rate were determined for 10 individuals with mild mental retardation (MR), 7 individuals with Down syndrome (DS), and 10 matched controls. MR and DS groups both had brain volumes of about 80% compared to controls, with variance greatest within the MR group. (SLD)

  7. Individual (co)variation in standard metabolic rate, feeding rate, and exploratory behavior in wild-caught semiaquatic salamanders.

    PubMed

    Gifford, Matthew E; Clay, Timothy A; Careau, Vincent

    2014-01-01

    Repeatability is an important concept in evolutionary analyses because it provides information regarding the benefit of repeated measurements and, in most cases, a putative upper limit to heritability estimates. Repeatability (R) of different aspects of energy metabolism and behavior has been demonstrated in a variety of organisms over short and long time intervals. Recent research suggests that consistent individual differences in behavior and energy metabolism might covary. Here we present new data on the repeatability of body mass, standard metabolic rate (SMR), voluntary exploratory behavior, and feeding rate in a semiaquatic salamander and ask whether individual variation in behavioral traits is correlated with individual variation in metabolism on a whole-animal basis and after conditioning on body mass. All measured traits were repeatable, but the repeatability estimates ranged from very high for body mass (R = 0.98), to intermediate for SMR (R = 0.39) and food intake (R = 0.58), to low for exploratory behavior (R = 0.25). Moreover, repeatability estimates for all traits except body mass declined over time (i.e., from 3 to 9 wk), although this pattern could be a consequence of the relatively low sample size used in this study. Despite significant repeatability in all traits, we find little evidence that behaviors are correlated with SMR at the phenotypic and among-individual levels when conditioned on body mass. Specifically, the phenotypic correlations between SMR and exploratory behavior were negative in all trials but significantly so in one trial only. Salamanders in this study showed individual variation in how their exploratory behavior changed across trials (but not body mass, SMR, and feed intake), which might have contributed to observed changing correlations across trials.

  8. Glycolysis-induced discordance between glucose metabolic rates measured with radiolabeled fluorodeoxyglucose and glucose

    SciTech Connect

    Ackermann, R.F.; Lear, J.L. )

    1989-12-01

    We have developed an autoradiographic method for estimating the oxidative and glycolytic components of local CMRglc (LCMRglc), using sequentially administered ({sup 18}F)fluorodeoxyglucose (FDG) and ({sup 14}C)-6-glucose (GLC). FDG-6-phosphate accumulation is proportional to the rate of glucose phosphorylation, which occurs before the divergence of glycolytic (GMg) and oxidative (GMo) glucose metabolism and is therefore related to total cerebral glucose metabolism GMt: GMg + GMo = GMt. With oxidative metabolism, the {sup 14}C label of GLC is temporarily retained in Krebs cycle-related substrate pools. We hypothesize that with glycolytic metabolism, however, a significant fraction of the {sup 14}C label is lost from the brain via lactate production and efflux from the brain. Thus, cerebral GLC metabolite concentration may be more closely related to GMo than to GMt. If true, the glycolytic metabolic rate will be related to the difference between FDG- and GLC-derived LCMRglc. Thus far, we have studied normal awake rats, rats with limbic activation induced by kainic acid (KA), and rats visually stimulated with 16-Hz flashes. In KA-treated rats, significant discordance between FDG and GLC accumulation, which we attribute to glycolysis, occurred only in activated limbic structures. In visually stimulated rats, significant discordance occurred only in the optic tectum.

  9. Effects of NaCl on metabolic heat evolution rates by barley roots

    NASA Technical Reports Server (NTRS)

    Criddle, R. S.; Hansen, L. D.; Breidenbach, R. W.; Ward, M. R.; Huffaker, R. C.

    1989-01-01

    The effect of salinity stress on metabolic heat output of barley (Hordeum vulgare L.) root tips was measured by isothermal microcalorimetry. Several varieties differing in tolerance to salinity were compared and differences quantified. Two levels of inhibition by increasing salt were found. Following the transition from the initial rate of the first level, inhibition remained at about 50% with further increases in salt concentration up to 150 millimolar. The concentration of salt required to inhibit to this level was cultivar dependent. At highter concentrations (>150 millimolar) of salt, metabolism was further decreased. This decrease was not cultivar dependent. The decreased rate of metabolic heat output at the first transition could be correlated with decreases in uptake of NO3-, NH4+, and Pi that occurred as the salt concentration was increased. The high degree of dependence of the inhibition of metabolic heat output on NaCl concentration points to a highly cooperative reaction responsible for the general inhibition of metabolism and nutrient uptake. The time required to attain the first level of salt inhibition is less than 20 minutes. Inhibition of root tips was not reversible by washing with salt free solutions. In addition to revealing these features of salt inhibition, isothermal microcalorimetry is a promising method for convenient and rapid determination of varietal differences in response to increasing salinity.

  10. Experimental study on trace chemical contaminant generation rates of human metabolism in spacecraft crew module

    NASA Astrophysics Data System (ADS)

    Lihua, Guo; Xinxing, He; Guoxin, Xu; Xin, Qi

    2012-12-01

    Trace chemical contaminants generated by human metabolism is a major source of contamination in spacecraft crew module. In this research, types and generation rates of pollutants from human metabolism were determined in the Chinese diets. Expired air, skin gas, and sweat of 20 subjects were analyzed at different exercise states in a simulated module. The exercise states were designed according to the basic activities in the orbit of astronauts. Qualitative and quantitative analyses of contaminants generated by human metabolic were performed with gas chromatography/mass spectrometry, gas chromatography and UV spectrophotometer. Sixteen chemical compounds from metabolic sources were found. With the increase in physical load, the concentrations of chemical compounds from human skin and expired air correspondingly increased. The species and the offgassing rates of pollutants from human metabolism are different among the Chinese, Americans and the Russians due to differences in ethnicity and dietary customs. This research provides data to aid in the design, development and operation of China's long duration space mission.

  11. Slight chronic elevation of C-reactive protein is associated with lower aerobic fitness but does not impair meal-induced stimulation of muscle protein metabolism in healthy old men

    PubMed Central

    Buffière, Caroline; Mariotti, François; Savary-Auzeloux, Isabelle; Migné, Carole; Meunier, Nathalie; Hercberg, Serge; Cano, Noel; Rémond, Didier; Duclos, Martine; Dardevet, Dominique

    2015-01-01

    Ageing impairs the muscle anabolic effect of food intake, which may explain muscle loss and an increased risk of sarcopenia. Ageing is also associated with low grade inflammation (LGI), which has been negatively correlated with muscle mass and strength. In rodents, the muscle anabolic resistance observed during ageing and sarcopenia has been ascribed to the development of the LGI. We aimed to investigate this relationship in humans. We studied protein metabolism and physical fitness in healthy elderly volunteers with slight chronic C-reactive protein. Two groups of healthy elderly volunteers were selected on the presence (or not) of a chronic, slight, elevation of CRP (Control: <1; CRP+: >2 mg l−1 and <10 mg l−1, for 2 months). Body composition, short performance battery test, aerobic fitness and muscle strength were assessed. Whole body and muscle protein metabolism and the splanchnic extraction of amino acids were assessed using [13C]leucine and [2H]leucine infusion. The anabolic effect of food intake was measured by studying the volunteers both at the post-absorptive and post-prandial states. Slight chronic CRP elevation resulted in neither an alteration of whole body, nor skeletal muscle protein metabolism at both the post-absorptive and the post-prandial states. However, CRP+ presented a reduction of physical fitness, increased abdominal fat mass and post-prandial insulin resistance. Plasma cytokines (interleukin-1, interleukin-6, tumour necrosis factor α) and markers of endothelial inflammation (intercellular adhesion molecule, vascular cell adhesion molecule, selectins) were similar between groups. An isolated elevated CRP in healthy older population does not indicate an impaired skeletal muscle anabolism after food intake, nor an increased risk of skeletal muscle wasting. We propose that a broader picture of LGI (notably with elevated pro-inflammatory cytokines) is required to impact muscle metabolism and mass. However, an isolated chronic CRP

  12. On the depth and scale of metabolic rate variation: scaling of oxygen consumption rates and enzymatic activity in the Class Cephalopoda (Mollusca).

    PubMed

    Seibel, Brad A

    2007-01-01

    Recent ecological theory depends, for predictive power, on the apparent similarity of metabolic rates within broad taxonomic or functional groups of organisms (e.g. invertebrates or ectotherms). Such metabolic commonality is challenged here, as I demonstrate more than 200-fold variation in metabolic rates independent of body mass and temperature in a single class of animals, the Cephalopoda, over seven orders of magnitude size range. I further demonstrate wide variation in the slopes of metabolic scaling curves. The observed variation in metabolism reflects differential selection among species for locomotory capacity rather than mass or temperature constraints. Such selection is highest among epipelagic squids (Lolignidae and Ommastrephidae) that, as adults, have temperature-corrected metabolic rates higher than mammals of similar size.

  13. Timing and Variability of Galactose Metabolic Gene Activation Depend on the Rate of Environmental Change.

    PubMed

    Nguyen-Huu, Truong D; Gupta, Chinmaya; Ma, Bo; Ott, William; Josić, Krešimir; Bennett, Matthew R

    2015-07-01

    Modulation of gene network activity allows cells to respond to changes in environmental conditions. For example, the galactose utilization network in Saccharomyces cerevisiae is activated by the presence of galactose but repressed by glucose. If both sugars are present, the yeast will first metabolize glucose, depleting it from the extracellular environment. Upon depletion of glucose, the genes encoding galactose metabolic proteins will activate. Here, we show that the rate at which glucose levels are depleted determines the timing and variability of galactose gene activation. Paradoxically, we find that Gal1p, an enzyme needed for galactose metabolism, accumulates more quickly if glucose is depleted slowly rather than taken away quickly. Furthermore, the variability of induction times in individual cells depends non-monotonically on the rate of glucose depletion and exhibits a minimum at intermediate depletion rates. Our mathematical modeling suggests that the dynamics of the metabolic transition from glucose to galactose are responsible for the variability in galactose gene activation. These findings demonstrate that environmental dynamics can determine the phenotypic outcome at both the single-cell and population levels.

  14. Effect of dietary fatty acids on metabolic rate and nonshivering thermogenesis in golden hamsters.

    PubMed

    Jefimow, Małgorzata; Wojciechowski, Michał S

    2014-02-01

    Hibernating rodents prior to winter tend to select food rich in polyunsaturated fatty acids (PUFA). Several studies found that such diet may positively affect their winter energy budget by enhancing torpor episodes. However, the effect of composition of dietary fatty acids (FA) on metabolism of normothermic heterotherms is poorly understood. Thus we tested whether diets different in FA composition affect metabolic rate (MR) and the capacity for nonshivering thermogenesis (NST) in normothermic golden hamsters (Mesocricetus auratus). Animals were housed in outdoor enclosures from May 2010 to April 2011 and fed a diet enriched with PUFA (i.e., standard food supplemented weekly with sunflower and flax seeds) or with saturated and monounsaturated fatty acids (SFA/MUFA, standard food supplemented with mealworms). Since diet rich in PUFA results in lower MR in hibernating animals, we predicted that PUFA-rich diet would have similar effect on MR of normothermic hamsters, that is, normothermic hamsters on the PUFA diet would have lower metabolic rate in cold and higher NST capacity than hamsters supplemented with SFA/MUFA. Indeed, in winter resting metabolic rate (RMR) below the lower critical temperature was higher and NST capacity was lower in SFA/MUFA-supplemented animals than in PUFA-supplemented ones. These results suggest that the increased capacity for NST in PUFA-supplemented hamsters enables them lower RMR below the lower critical temperature of the thermoneural zone.

  15. Trade-Offs between the Metabolic Rate and Population Density of Plants

    PubMed Central

    Deng, Jian-Ming; Li, Tao; Wang, Gen-Xuan; Liu, Jing; Yu, Ze-Long; Zhao, Chang-Ming; Ji, Ming-Fei; Zhang, Qiang; Liu, Jian-quan

    2008-01-01

    The energetic equivalence rule, which is based on a combination of metabolic theory and the self-thinning rule, is one of the fundamental laws of nature. However, there is a progressively increasing body of evidence that scaling relationships of metabolic rate vs. body mass and population density vs. body mass are variable and deviate from their respective theoretical values of 3/4 and −3/4 or −2/3. These findings questioned the previous hypotheses of energetic equivalence rule in plants. Here we examined the allometric relationships between photosynthetic mass (Mp) or leaf mass (ML) vs. body mass (β); population density vs. body mass (δ); and leaf mass vs. population density, for desert shrubs, trees, and herbaceous plants, respectively. As expected, the allometric relationships for both photosynthetic mass (i.e. metabolic rate) and population density varied with the environmental conditions. However, the ratio between the two exponents was −1 (i.e. β/δ = −1) and followed the trade-off principle when local resources were limited. Our results demonstrate for the first time that the energetic equivalence rule of plants is based on trade-offs between the variable metabolic rate and population density rather than their constant allometric exponents. PMID:18350139

  16. Aerobic Development of Elite Youth Ice Hockey Players.

    PubMed

    Leiter, Jeff R; Cordingley, Dean M; MacDonald, Peter B

    2015-11-01

    Ice hockey is a physiologically complex sport requiring aerobic and anaerobic energy metabolism. College and professional teams often test aerobic fitness; however, there is a paucity of information regarding aerobic fitness of elite youth players. Without this knowledge, training of youth athletes to meet the standards of older age groups and higher levels of hockey may be random, inefficient, and or effective. Therefore, the purpose of this study was to determine the aerobic fitness of elite youth hockey players. A retrospective database review was performed for 200 male AAA hockey players between the ages of 13 and 17 (age, 14.4 ± 1.2 years; height, 174.3 ± 8.5 cm; body mass, 67.2 ± 11.5 kg; body fat, 9.8 ± 3.5%) before the 2012-13 season. All subjects performed a graded exercise test on a cycle ergometer, whereas expired air was collected by either a Parvo Medics TrueOne 2400 or a CareFusion Oxycon Mobile metabolic cart to determine maximal oxygen consumption (V[Combining Dot Above]O2max). Body mass, absolute V[Combining Dot Above]O2max, and the power output achieved during the last completed stage increased in successive age groups from age 13 to 15 years (p ≤ 0.05). Ventilatory threshold (VT) expressed as a percentage of V[Combining Dot Above]O2max and the heart rate (HR) at which VT occurred decreased between the ages of 13 and 14 years (p ≤ 0.05), whereas the V[Combining Dot Above]O2 at which VT occurred increased from the age of 14-15 years. There were no changes in relative V[Combining Dot Above]O2max or HRmax between any successive age groups. The aerobic fitness levels of elite youth ice hockey players increased as players age and mature physically and physiologically. However, aerobic fitness increased to a lesser extent at older ages. This information has the potential to influence off-season training and maximize the aerobic fitness of elite amateur hockey players, so that these players can meet standards set by advanced elite age groups.

  17. Pulmonary diffusional screening and the scaling laws of mammalian metabolic rates

    NASA Astrophysics Data System (ADS)

    Hou, Chen; Mayo, Michael

    2011-12-01

    Theoretical considerations suggest that the mammalian metabolic rate is linearly proportional to the surface areas of mitochondria, capillary, and alveolar membranes. However, the scaling exponents of these surface areas to the mammals' body mass (approximately 0.9-1) are higher than exponents of the resting metabolic rate (RMR) to body mass (approximately 0.75), although similar to the one of exercise metabolic rate (EMR); the underlying physiological cause of this mismatch remains unclear. The analysis presented here shows that discrepancies between the scaling exponents of RMR and the relevant surface areas may originate from, at least for the system of alveolar membranes in mammalian lungs, the facts that (i) not all of the surface area is involved in the gas exchange and (ii) that larger mammals host a smaller effective surface area that participates in the material exchange rate. A result of these facts is that lung surface areas unused at rest are activated under heavy breathing conditions (e.g., exercise), wherein larger mammals support larger activated surface areas that provide a higher capability to increase the gas-exchange rate, allowing for mammals to meet, for example, the high energetic demands of foraging and predation.

  18. Pulmonary diffusional screening and the scaling laws of mammalian metabolic rates.

    PubMed

    Hou, Chen; Mayo, Michael

    2011-12-01

    Theoretical considerations suggest that the mammalian metabolic rate is linearly proportional to the surface areas of mitochondria, capillary, and alveolar membranes. However, the scaling exponents of these surface areas to the mammals' body mass (approximately 0.9-1) are higher than exponents of the resting metabolic rate (RMR) to body mass (approximately 0.75), although similar to the one of exercise metabolic rate (EMR); the underlying physiological cause of this mismatch remains unclear. The analysis presented here shows that discrepancies between the scaling exponents of RMR and the relevant surface areas may originate from, at least for the system of alveolar membranes in mammalian lungs, the facts that (i) not all of the surface area is involved in the gas exchange and (ii) that larger mammals host a smaller effective surface area that participates in the material exchange rate. A result of these facts is that lung surface areas unused at rest are activated under heavy breathing conditions (e.g., exercise), wherein larger mammals support larger activated surface areas that provide a higher capability to increase the gas-exchange rate, allowing for mammals to meet, for example, the high energetic demands of foraging and predation.

  19. Aerobic Fitness for the Moderately Retarded.

    ERIC Educational Resources Information Center

    Bauer, Dan

    1981-01-01

    Intended for physical education teachers, the booklet offers ideas for incorporating aerobic conditioning into programs for moderately mentally retarded students. An explanation of aerobic fitness and its benefits is followed by information on initiating a fitness program with evaluation of height, weight, body fat, resting heart rate, and…

  20. Metabolic rates in an anadromous clupeid, the American shad (Alosa sapidissima)

    USGS Publications Warehouse

    Leonard, J.B.K.; Norieka, J.F.; Kynard, B.; McCormick, S.D.

    1999-01-01

    To assess the energetics of migration in an anadromous fish, adult American shad (Alosa sapidissima) were swum in a large respirometer at a range of speeds (1.0–2.3 body lengths (BL) s−1, 13–24 °C). Metabolic rate (MO2) was logarithmically related to swimming speed (Bl s−1; r2 = 0.41, slope = 0.23 ± 0.037) and tailbeat frequency (beats × min−1; r2 = 0.52, slope = 0.003 ± 0.0003). Temperature had a significant effect on metabolic rate (r2 = 0.41) with a Q10of 2.2. Standard metabolic rate (SMR), determined directly after immobilization with the neuroblocker gallamine triethiodide, ranged from 2.2–6.2 mmolO2 kg−1 h−1 and scaled with mass (W) such that SMR = 4.0 (±0.03)W0.695(±0.15). Comparison of directly determined and extrapolated SMR suggests that swimming respirometry provides a good estimate of SMR in this species, given the differences in basal activity monitored by the two methods. Overall, American shad metabolic rates (MO2 and SMR) were intermediate between salmonids and fast-swimming perciforms, including tunas, and may be a result of evolutionary adaptation to their active pelagic, schooling life history. This study demonstrates variability in metabolic strategy among anadromous fishes that may be important to understanding the relative success of different migratory species under varying environmental conditions.

  1. Seasonal variation in metabolic rate, flight activity and body size of Anopheles gambiae in the Sahel

    PubMed Central

    Huestis, Diana L.; Yaro, Alpha S.; Traoré, Adama I.; Dieter, Kathryne L.; Nwagbara, Juliette I.; Bowie, Aleah C.; Adamou, Abdoulaye; Kassogué, Yaya; Diallo, Moussa; Timbiné, Seydou; Dao, Adama; Lehmann, Tovi

    2012-01-01

    SUMMARY Malaria in Africa is vectored primarily by the Anopheles gambiae complex. Although the mechanisms of population persistence during the dry season are not yet known, targeting dry season mosquitoes could provide opportunities for vector control. In the Sahel, it appears likely that M-form A. gambiae survive by aestivation (entering a dormant state). To assess the role of eco-physiological changes associated with dry season survival, we measured body size, flight activity and metabolic rate of wild-caught mosquitoes throughout 1 year in a Sahelian locality, far from permanent water sources, and at a riparian location adjacent to the Niger River. We found significant seasonal variation in body size at both the Sahelian and riparian sites, although the magnitude of the variation was greater in the Sahel. For flight activity, significant seasonality was only observed in the Sahel, with increased flight activity in the wet season when compared with that just prior to and throughout the dry season. Whole-organism metabolic rate was affected by numerous biotic and abiotic factors, and a significant seasonal component was found at both locations. However, assay temperature accounted completely for seasonality at the riparian location, while significant seasonal variation remained after accounting for all measured variables in the Sahel. Interestingly, we did not find that mean metabolic rate was lowest during the dry season at either location, contrary to our expectation that mosquitoes would conserve energy and increase longevity by reducing metabolism during this time. These results indicate that mosquitoes may use mechanisms besides reduced metabolic rate to enable survival during the Sahelian dry season. PMID:22623189

  2. Effects of aerobic training intensity on resting, exercise and post-exercise blood pressure, heart rate and heart-rate variability.

    PubMed

    Cornelissen, V A; Verheyden, B; Aubert, A E; Fagard, R H

    2010-03-01

    We aimed to investigate the effects of endurance training intensity (1) on systolic blood pressure (SBP) and heart rate (HR) at rest before exercise, and during and after a maximal exercise test; and (2) on measures of HR variability at rest before exercise and during recovery from the exercise test, in at least 55-year-old healthy sedentary men and women. A randomized crossover study comprising three 10-week periods was performed. In the first and third period, participants exercised at lower or higher intensity (33% or 66% of HR reserve) in random order, with a sedentary period in between. Training programmes were identical except for intensity, and were performed under supervision thrice for 1 h per week. The results show that in the three conditions, that is, at rest before exercise, during exercise and during recovery, we found endurance training at lower and higher intensity to reduce SBP significantly (P<0.05) and to a similar extent. Further, SBP during recovery was, on average, not lower than at rest before exercise, and chronic endurance training did not affect the response of SBP after an acute bout of exercise. The effect of training on HR at rest, during exercise and recovery was more pronounced (P<0.05) with higher intensity. Finally, endurance training had no significant effect on sympathovagal balance. In conclusion, in participants at higher age, both training programmes exert similar effects on SBP at rest, during exercise and during post-exercise recovery, whereas the effects on HR are more pronounced after higher intensity training.

  3. Shoaling reduces metabolic rate in a gregarious coral reef fish species

    PubMed Central

    Killen, Shaun S.; McClure, Eva C.; Munday, Philip L.; McCormick, Mark I.

    2016-01-01

    ABSTRACT Many animals live in groups because of the potential benefits associated with defense and foraging. Group living may also induce a ‘calming effect’ on individuals, reducing overall metabolic demand. This effect could occur by minimising the need for individual vigilance and reducing stress through social buffering. However, this effect has proved difficult to quantify. We examined the effect of shoaling on metabolism and body condition in the gregarious damselfish Chromis viridis. Using a novel respirometry methodology for social species, we found that the presence of shoal-mate visual and olfactory cues led to a reduction in the minimum metabolic rate of individuals. Fish held in isolation for 1 week also exhibited a reduction in body condition when compared with those held in shoals. These results indicate that social isolation as a result of environmental disturbance could have physiological consequences for gregarious species. PMID:27655821

  4. Metabolic Rate Regulation by the Renin-Angiotensin System: Brain vs. Body

    PubMed Central

    Grobe, Justin L.; Rahmouni, Kamal; Liu, Xuebo; Sigmund, Curt D.

    2013-01-01

    Substantial evidence supports a role for the renin-angiotensin system (RAS) in the regulation of metabolic function, but an apparent paradox exists where genetic or pharmacological inhibition of the RAS occasionally have similar physiological effects as chronic angiotensin infusion. Similarly, while RAS targeting in animal models has robust metabolic consequences, effects in humans are more subtle. Here we review the data supporting a role for the RAS in metabolic rate regulation and propose a model where the local brain RAS works in opposition to the peripheral RAS, thus helping to explain the paradoxically similar effects of RAS supplementation and inhibition. Selectively modulating the peripheral RAS or brain RAS may thus provide a more effective treatment paradigm for obesity and obesity-related disorders. PMID:22491893

  5. Cellular oxidative damage is more sensitive to biosynthetic rate than to metabolic rate: A test of the theoretical model on hornworms (Manduca sexta larvae).

    PubMed

    Amunugama, Kaushalya; Jiao, Lihong; Olbricht, Gayla R; Walker, Chance; Huang, Yue-Wern; Nam, Paul K; Hou, Chen

    2016-09-01

    We develop a theoretical model from an energetic viewpoint for unraveling the entangled effects of metabolic and biosynthetic rates on oxidative cellular damage accumulation during animal's growth, and test the model by experiments in hornworms. The theoretical consideration suggests that most of the cellular damages caused by the oxidative metabolism can be repaired by the efficient maintenance mechanisms, if the energy required by repair is unlimited. However, during growth a considerable amount of energy is allocated to the biosynthesis, which entails tradeoffs with the requirements of repair. Thus, the model predicts that cellular damage is more influenced by the biosynthetic rate than the metabolic rate. To test the prediction, we induced broad variations in metabolic and biosynthetic rates in hornworms, and assayed the lipid peroxidation and protein carbonyl. We found that the increase in the cellular damage was mainly caused by the increase in biosynthetic rate, and the variations in metabolic rate had negligible effect. The oxidative stress hypothesis of aging suggests that high metabolism leads to high cellular damage and short lifespan. However, some empirical studies showed that varying biosynthetic rate, rather than metabolic rate, changes animal's lifespan. The conflicts between the empirical evidence and the hypothesis are reconciled by this study.

  6. Brain aerobic glycolysis and motor adaptation learning

    PubMed Central

    Shannon, Benjamin J.; Vaishnavi, Sanjeev Neil; Vlassenko, Andrei G.; Shimony, Joshua S.; Rutlin, Jerrel; Raichle, Marcus E.

    2016-01-01

    Ten percent to 15% of glucose used by the brain is metabolized nonoxidatively despite adequate tissue oxygenation, a process termed aerobic glycolysis (AG). Because of the known role of glycolysis in biosynthesis, we tested whether learning-induced synaptic plasticity would lead to regionally appropriate, learning-dependent changes in AG. Functional MRI (fMRI) before, during, and after performance of a visual–motor adaptation task demonstrated that left Brodmann area 44 (BA44) played a key role in adaptation, with learning-related changes to activity during the task and altered resting-state, functional connectivity after the task. PET scans before and after task performance indicated a sustained increase in AG in left BA 44 accompanied by decreased oxygen consumption. Intersubject variability in behavioral adaptation rate correlated strongly with changes in AG in this region, as well as functional connectivity, which is consistent with a role for AG in synaptic plasticity. PMID:27217563

  7. Effects of topiramate use on body composition and resting metabolic rate in migraine patients.

    PubMed

    Yaman, Mehmet; Ucok, Kagan; Demirbas, Hayri; Genc, Abdurrahman; Oruc, Serdar; Karabacak, Hatice; Koyuncu, Gokhan

    2013-02-01

    Topiramate is an anticonvulsant agent effective in the prophylaxis of migraine, which also induces weight reduction by an unknown mechanism. We investigated the effect of topiramate on resting metabolic rate, anthropometric measurements, and body composition in patients with migraine independently from any intention to lose body weight. Forty patients (18-71 years old) with migraine were treated with 100 mg of topiramate/day over a period of 3 months. Anthropometric measurements, body fat proportions and resting metabolic rates of these patients were measured before and after treatment. At the end of 3 months, we detected mean 0.8 kg reduction in body weight and 0.3 kg/m(2) reduction in body mass index (BMI). Waist circumference decreased significantly (p = 0.01). Body fat ratio decreased (p = 0.016). Abdominal skinfold measurements decreased after treatment (p = 0.048); however, no difference was found in other regions (p > 0.05). We did not find a significant difference in resting metabolic rate (p > 0.05).These TPM-treated patients lost weight and had reduction in their mean BMI. It was seen that patients lost weight from body fat tissue and central area. We saw that TPM'S weight-reducing effect was independent from resting metaobolic rate. The weight-reducing effect of TPM may result from changes on the hypothalamus.

  8. Consequences of complex environments: Temperature and energy intake interact to influence growth and metabolic rate.

    PubMed

    Stahlschmidt, Zachary R; Jodrey, Alicia D; Luoma, Rachel L

    2015-09-01

    The field of comparative physiology has a rich history of elegantly examining the effects of individual environmental factors on performance traits linked to fitness (e.g., thermal performance curves for locomotion). However, animals live in complex environments wherein multiple environmental factors co-vary. Thus, we investigated the independent and interactive effects of temperature and energy intake on the growth and metabolic rate of juvenile corn snakes (Pantherophis guttatus) in the context of shifts in complex environments. Unlike previous studies that imposed constant or fluctuating temperature regimes, we manipulated the availability of preferred thermal microclimates (control vs. relatively warm regimes) for eight weeks and allowed snakes to behaviorally thermoregulate among microclimates. By also controlling for energy intake, we demonstrate an interactive effect of temperature and energy on growth-relevant temperature shifts had no effect on snakes' growth when energy intake was low and a positive effect on growth when energy intake was high. Thus, acclimation to relatively warm thermal options can result in increased rates of growth when food is abundant in a taxon in which body size confers fitness advantages. Temperature and energy also interactively influenced metabolic rate-snakes in the warmer temperature regime exhibited reduced metabolic rate (O2 consumption rate at 25 °C and 30 °C) if they had relatively high energy intake. Although we advocate for continued investigation into the effects of complex environments on other traits, our results indicate that warming may actually benefit important life history traits in some taxa and that metabolic shifts may underlie thermal acclimation.

  9. Low global sensitivity of metabolic rate to temperature in calcified marine invertebrates.

    PubMed

    Watson, Sue-Ann; Morley, Simon A; Bates, Amanda E; Clark, Melody S; Day, Robert W; Lamare, Miles; Martin, Stephanie M; Southgate, Paul C; Tan, Koh Siang; Tyler, Paul A; Peck, Lloyd S

    2014-01-01

    Metabolic rate is a key component of energy budgets that scales with body size and varies with large-scale environmental geographical patterns. Here we conduct an analysis of standard metabolic rates (SMR) of marine ectotherms across a 70° latitudinal gradient in both hemispheres that spanned collection temperatures of 0-30 °C. To account for latitudinal differences in the size and skeletal composition between species, SMR was mass normalized to that of a standard-sized (223 mg) ash-free dry mass individual. SMR was measured for 17 species of calcified invertebrates (bivalves, gastropods, urchins and brachiopods), using a single consistent methodology, including 11 species whose SMR was described for the first time. SMR of 15 out of 17 species had a mass-scaling exponent between 2/3 and 1, with no greater support for a 3/4 rather than a 2/3 scaling exponent. After accounting for taxonomy and variability in parameter estimates among species using variance-weighted linear mixed effects modelling, temperature sensitivity of SMR had an activation energy (Ea) of 0.16 for both Northern and Southern Hemisphere species which was lower than predicted under the metabolic theory of ecology (Ea 0.2-1.2 eV). Northern Hemisphere species, however, had a higher SMR at each habitat temperature, but a lower mass-scaling exponent relative to SMR. Evolutionary trade-offs that may be driving differences in metabolic rate (such as metabolic cold adaptation of Northern Hemisphere species) will have important impacts on species abilities to respond to changing environments.

  10. Nicotine metabolic rate predicts successful smoking cessation with transdermal nicotine: a validation study.

    PubMed

    Schnoll, Robert A; Patterson, Freda; Wileyto, E Paul; Tyndale, Rachel F; Benowitz, Neal; Lerman, Caryn

    2009-03-01

    Transdermal nicotine is widely used for smoking cessation, but only approximately 20% of smokers quit successfully with this medication. Interindividual variability in nicotine metabolism rate may influence treatment response. This study sought to validate, and extend in a larger sample, our previous finding that the ratio of plasma nicotine metabolites 3'-hydroxycotinine (3-HC)/cotinine, a measure of nicotine metabolism rate, predicts response to nicotine patch. A sample of 568 smokers was enrolled in a study that provided counseling and 8-weeks of 21 mg nicotine patch. Pretreatment 3-HC/cotinine ratio was examined as a predictor of 7-day point prevalence abstinence, verified with breath carbon monoxide (CO), 8 weeks after the quit date. Controlling for sex, race, age, and nicotine dependence, smokers in the upper 3 quartiles of 3-HC/cotinine ratio (faster metabolizers) were approximately 50% less likely to be abstinent vs. smokers in the first quartile (slow metabolizers; 28% vs. 42%; OR=.54 [95% CI:.36-.82], p=.003). Among abstainers, plasma nicotine levels (assessed 1 week after treatment began) decreased linearly across the 3-HC/cotinine ratio (beta=-3.38, t[355]=-3.09, p<.05). These data support the value of the 3-HC/cotinine ratio as a biomarker to predict success with transdermal nicotine for smoking cessation.

  11. Understanding evolutionary variation in basal metabolic rate: An analysis in subterranean rodents.

    PubMed

    Luna, Facundo; Naya, Hugo; Naya, Daniel E

    2017-04-01

    Understanding how evolutionary variation in energetic metabolism arises is central to several theories in animal biology. Basal metabolic rate (BMR) -i.e., the minimum rate of energy necessary to maintain thermal homeostasis in endotherms- is a highly informative measure to increase our understanding, because it is determined under highly standardized conditions. In this study we evaluate the relationship between taxa- and mass-independent (residual) BMR and ten environmental factors for 34 subterranean rodent species. Both conventional and phylogenetically informed analyses indicate that ambient temperature is the major determinant of residual BMR, with both variables inversely correlated. By contrast, other environmental factors that have been shown to affect residual BMR in endotherms, such as habitat productivity and rainfall, were not significant predictors of residual BMR in this group of species. Then, the results for subterranean rodents appear to support a central prediction of the obligatory heat model (OHM), which is a mechanistic model aimed to explain the evolution of residual BMR. Specifically, OHM proposes that during the colonization of colder environments, individuals with greater masses of metabolically expensive tissues (and thus with greater BMR) are favored by natural selection due to the link between greater masses of metabolically expensive tissues and physiological capacities. This way, natural selection should establishes a negative correlation between ambient temperature and both internal organ size and residual BMR.

  12. Metabolic rate M  0.75 in human beings

    NASA Astrophysics Data System (ADS)

    Agrawal, D. C.

    2014-11-01

    Human beings consume energy every day. Even at rest, energy is still needed for the working of the internal organs. This is achieved by the metabolism of consumed food in the presence of inhaled oxygen. During the resting state this is called the maintenance rate, and follows the mouse-to-elephant formula, Pmet = 70M0.75 kcal per day. Here, M is the body mass of the subject in kilograms. The heat generated in metabolism is lost through the body surface of the subject, so the metabolic rate should also be proportional to the body surface area. In other words, the body surface area in the case of a human being must also depend on M0.75. The present paper examines this issue by finding a relationship between human body surface area and its mass through a very simple model that can be easily understood and verified by physics students, who can also compare it with all the expressions for body surface area available in the literature. This will build confidence in the students that the heat generated from metabolism in fact dissipates through the surface of the body.

  13. COMPARISON OF IN VIVO DERIVED AND SCALED IN VITRO METABOLIC RATE CONSTANTS FOR SOME VOLATILE ORGANIC COMPOUNDS (VOCS)

    EPA Science Inventory

    The reliability of physiologically based pharmacokinetic (PBPK) models is directly related to the accuracy of the metabolic rate parameters used as model inputs. When metabolic rate parameters derived from in vivo experiments are unavailable, they can be estimated from in vitro d...

  14. Metabolic rate of carrying added mass: a function of walking speed, carried mass and mass location.

    PubMed

    Schertzer, Eliran; Riemer, Raziel

    2014-11-01

    The effort of carrying additional mass at different body locations is important in ergonomics and in designing wearable robotics. We investigate the metabolic rate of carrying a load as a function of its mass, its location on the body and the subject's walking speed. Novel metabolic rate prediction equations for walking while carrying loads at the ankle, knees and back were developed based on experiments where subjects walked on a treadmill at 4, 5 or 6km/h bearing different amounts of added mass (up to 2kg per leg and 22kg for back). Compared to previously reported equations, ours are 7-69% more accurate. Results also show that relative cost for carrying a mass at a distal versus a proximal location changes with speed and mass. Contrary to mass carried on the back, mass attached to the leg cannot be modeled as an increase in body mass.

  15. Energetics of stress: linking plasma cortisol levels to metabolic rate in mammals.

    PubMed

    Haase, Catherine G; Long, Andrea K; Gillooly, James F

    2016-01-01

    Physiological stress may result in short-term benefits to organismal performance, but also long-term costs to health or longevity. Yet, we lack an understanding of the variation in stress hormone levels (i.e. glucocorticoids) that exist within and across species. Here, we present comparative analyses that link the primary stress hormone in most mammals (i.e. cortisol) to metabolic rate. We show that baseline concentrations of plasma cortisol vary with mass-specific metabolic rate among cortisol-dominant mammals, and both baseline and elevated concentrations scale predictably with body mass. The results quantitatively link a classical measure of physiological stress to whole-organism energetics, providing a point of departure for cross-species comparisons of stress levels among mammals.

  16. Influence of respirometry methods on intraspecific variation in standard metabolic rates in newts.

    PubMed

    Kristín, Peter; Gvoždík, Lumír

    2012-09-01

    Standard metabolic rate (SMR) is both a highly informative and variable trait. Variation in SMR stems not only from diverse intrinsic and extrinsic factors, but also from the use of diverse methods for metabolic measurements. We measured CO(2) production (VCO(2)) and oxygen consumption rates (VO(2)) using two flow-through respirometry modes, continuous and intermittent (stop-flow), to evaluate their potential contribution to SMR variation in Alpine newts, Ichthyosaura alpestris. Both respirometry modes yielded similar and repeatable VCO(2