Capacity For Aerobic Metabolism Research Articles

Deteriorated abatement of micropollutants in biological activated carbon filters with aged media: Key role of permeability.

Biological activated carbon (BAC) filtration is vital for the abatement of micropollutants in drinking water. However, limited information is available on contaminant removal in BAC filters with aged media (e.g., >6 year) which are commonly operated at water treatment plants, and mechanistic insights into linkages among media age, microbial community, and contaminant removal still lack. In this study, the effects of media age on the abatement of eight micropollutants with various functional groups were investigated. The abatement of micropollutants decreased with increasing media age. Pseudo-first-order rate constants for contaminant removal in 6- and 15-year BAC were (0.3-3.1) × 10-3 and (0.2-2.6) × 10-3 s-1, compared to (0.9-4.3) × 10-3 s-1 in 3.5-year BAC filter. Biosorption- and biodegradation-dominated contaminant removal depended on protein and adenosine triphosphate concentrations in biofilm, respectively. Micro-computed tomography revealed the formation of biofilm-dominated clogging with rare voids and channels in 15-year BAC, resulting in low permeability. The decreased permeability led to deficient dissolved O2 and nutrient supply and thus changed microbial community assembly process, reducing community diversity and function. Core members including families of Saprospiraceae, Chitinophagaceae, Rhodocyclaceae, Comamonadaceae, and Nitrospiraceae in 3.5-year BAC were affiliated with active aerobic metabolism and contaminant biodegradation capacity. Abundances of these functional microbes and genes decreased with increasing media age. Simultaneously, protein in biofilm decreased, thereby decreasing biosorption. The findings of this study reveal the pivotal role of permeability in shaping microbial community and function and the corresponding micropollutant removal in BAC filters with aged media.

Aerobic and anaerobic poise of white swimming muscles of the deep-diving scalloped hammerhead shark: comparison to sympatric coastal and deep-water species

Scalloped hammerhead sharks (Sphyrna lewini) routinely perform rapid dives to forage on mesopelagic prey. These deep dives consist of intensive swimming followed by recovery periods in the surface mixed layer. Swimming muscle temperature profiles suggest that S. lewini suppresses gill function as a means to reduce convective heat loss during dives into cool water. Such intensive swimming behavior coupled with reduced respiration prompted us to test whether the aerobic and anaerobic metabolic capacities of the white swimming muscle tissue of this species are greater than those of other shark species from the same region. The activities of key enzymes used in aerobic and anaerobic metabolism provide an indirect indicator of the metabolic potential (“poise”) of a tissue. Here we measured the maximal activities [international units (µmol substrate converted to product per min, U) per gram of wet tissue mass at 10°C] of the citric acid cycle enzymes citrate synthase (CS) and malate dehydrogenase (MDH) and glycolytic enzymes pyruvate kinase (PK) and lactate dehydrogenase (LDH) from white swimming muscle of S. lewini. Enzyme activities, and ratios of these enzyme activities that indicate relative indexes of aerobic to anaerobic capacity, were compared to those measured in three sympatric coastal carcharhinid sharks and two deep-dwelling species, Echinorhinus cookei and Hexanchus griseus. This is the first report of swimming-muscle enzyme activity for these deep-dwelling species. In comparison to the other species, S. lewini had significantly higher activities of both LDH and MDH in the white muscle, and a higher MDH/CS ratio. The high LDH activities suggest that the white muscle of S. lewini relies on relatively high rates of anaerobic ATP production, with would result in build up of high lactate levels, during deep foraging dives. High MDH activity in S. lewini white muscle suggests the potential for lactate levels to be rapidly reduced when aerobic conditions are restored while in the surface mixed layer between dives. These biochemical characteristics may enable S. lewini to swim rapidly while suppressing gill function during deep dives and thereby exploit a very different ecological niche from sympatric shark species (e.g., coastal carcharhinids) and hunt more rapidly via faster swimming for deep-water prey compared to species that permanently inhabit deep depths.

Anaerobic and Aerobic Metabolic Capacities Contributing to Yo-Yo Intermittent Recovery Level 2 Test Performance in Australian Rules Footballers.

This study aimed to identify the aerobic and anaerobic metabolic performance capacities contributing to Yo-Yo Intermittent Recovery level 2 (Yo-Yo IR2) test performance. Nineteen recreational Australian footballers completed a Yo-Yo IR2 test, and on another day a treadmill peak oxygen uptake (VO2peak) and maximal accumulated oxygen deficit test in a randomised counter-balanced order. The maximal accumulated oxygen deficit (MAOD) procedures included 5 × 5 min sub-maximal continuous runs at progressively higher speeds whilst VO2 was recorded; thereafter, speed was incrementally increased to elicit VO2peak. After 35 min of rest, participants ran at a speed equivalent to 115% of VO2peak until exhaustion, at which point expired air was collected to determine maximal accumulated oxygen deficit. Relationships between variables were assessed using Pearson's correlation and partial correlations. Maximum aerobic speed, relative intensity, and VO2peak were significantly correlated with Yo-Yo IR2 performance. High Yo-Yo IR2 performers also had higher MAS, relative intensity, and VO2peak levels. However, when higher maximum aerobic speed, relative intensity, and VO2peak were controlled for each other and analysed independently, neither maximal aerobic speed nor VO2peak correlated with Yo-Yo IR2 performance. Yo-Yo IR2 performance is the result of a complex interaction between several variables. Training programs should primarily focus on improving VO2peak, maximal aerobic speed, and relative intensity to optimize Yo-Yo IR2 test performance.

Consistent changes in muscle phenotype and mitochondrial abundance underlie dive performance across multiple lineages of diving ducks.

Diving animals must sustain high muscle activity with finite oxygen (O2) to forage underwater. Studies have shown that some diving mammals exhibit changes in the metabolic phenotype of locomotory muscles compared with non-divers, but the pervasiveness of such changes across diving animals is unclear, particularly among diving birds. Here, we examined whether changes in muscle phenotype and mitochondrial abundance are associated with dive capacity across 17 species of ducks from three distinct evolutionary clades (tribes) in the subfamily Anatinae: the longest diving sea ducks, the mid-tier diving pochards and the non-diving dabblers. In the gastrocnemius (the primary swimming and diving muscle), mitochondrial volume density in both oxidative and glycolytic fiber types was 70% and 30% higher in sea ducks compared with dabblers, respectively. These differences were associated with preferential proliferation of the subsarcolemmal subfraction, the mitochondria adjacent to the cell membrane and nearest to capillaries, relative to the intermyofibrillar subfraction. Capillary density and capillary-to-fiber ratio were positively correlated with mitochondrial volume density, with no variation in the density of oxidative fiber types across tribes. In the pectoralis, sea ducks had greater abundance of oxidative fiber types than dabblers, whereas pochards were intermediate between the two. These data suggest that skeletal muscles of sea ducks have a heightened capacity for aerobic metabolism and an enhanced ability to utilize O2 stores in the blood and muscle while diving.

Does chronic exposure to moderate hypoxia affect growth, physiological and oxidative stress biomarkers in adult spotted wolffish (Anarhichas minor) and the hybrid A. minor × A. lupus?

AbstractBoth in their natural habitat (estuaries, marine coastal environment, ocean depths and freshwater lakes) or in captivity conditions (land‐based, open‐sea aquaculture and aquariums), exposure to hypoxia can have direct detrimental effects on fish growth, reproduction, behaviour and health. The objective of this study was to investigate the effects of chronic exposure of spotted wolffish (Anarhichas minor) (∼1.4 kg) and the interspecific hybrid (A. minor × A. lupus) (∼600 g) to moderate hypoxia levels (dissolved oxygen [DO]: 40%, 50% and 60% saturation) in comparison to a normoxia group (control 100%) over a period of 14 weeks at ∼7.5°C. The trials were conducted as a common‐garden experiment (both fish groups reared together) in quadruplicate (4 tanks per DO level = 16 tanks). Fish performance (specific growth rate, feed intake [FI]) and physiological status (condition factor [K] and hepatosomatic index, haematocrit) were monitored at different intervals. The metabolic enzyme activity of citrate synthase (CS), lactate dehydrogenase (LDH) and pyruvate kinase (PK) was measured as well as antioxidant enzymes glutathione reductase and catalase. Oxidative stress indices were assessed by the quantification of thiobarbituric acid reactive substances (TBARS) and the measurement of the enzymatic activity level of aconitase. Significant reduction in growth rate occurred at DO 40%. DO was identified as a major driver of FI. Our results indicate a very strong adaptation to hypoxia as (1) exposures to DO 40% were not severe enough to affect aerobic or anaerobic metabolism capacity or to significantly induce oxidative stress and (2) metabolic organization of the muscle tissue, as expressed by LDH, CS and PK is not affected by DO levels down to 40%. However, at the lowest DO levels (40% and 50%), hybrid fish displayed significantly better growth than the spotted wolffish.

Flight muscle size reductions and functional changes following long-distance flight under variable humidity conditions in a migratory warbler.

Bird flight muscle can lose as much as 20% of its mass during a migratory flight due to protein catabolism, and catabolism can be further exacerbated under dehydrating conditions. However, the functional consequences of exercise and environment induced protein catabolism on muscle has not been examined. We hypothesized that prolonged flight would cause a decline in muscle mass, aerobic capacity, and contractile performance. This decline would be heightened for birds placed under dehydrating environmental conditions, which typically increases lean mass losses. Yellow-rumped warblers (Setophaga coronata) were exposed to dry or humid (12 or 80% relative humidity at 18°C) conditions for up to 6 h while at rest or undergoing flight. The pectoralis muscle was sampled after flight/rest or after 24 h of recovery, and contractile properties and enzymatic capacity for aerobic metabolism was measured. There was no change in lipid catabolism or force generation of the muscle due to flight or humidity, despite reductions in pectoralis dry mass immediately post-flight. However, there was a slowing of myosin-actin crossbridge kinetics under dry compared to humid conditions. Aerobic and contractile function is largely preserved after 6 h of exercise, suggesting that migratory birds preserve energy pathways and function in the muscle.

Long-Term Results of Serial Exercise Testing and Echocardiography Examinations in Patients with Pulmonary Stenosis.

Pulmonary stenosis (PS) affects cardiopulmonary function and exercise performance. Cardiopulmonary exercise testing (CPET) together with transthoracic echocardiography (TTE) can measure exercise performance, PS progression, and treatment effects. We assessed exercise capacity in PS patients using these methods. We enrolled 28 PS patients aged 6-35 years who received surgery, balloon pulmonary valvuloplasty, and follow-up care. The control population was selected by a 1:1 matching on age, sex, and body mass index. Baseline and follow-up peak pulmonary artery pulse wave velocity (PAV) were compared using TTE. Initial CPET revealed no significant differences in anaerobic metabolic equivalent (MET), peak oxygen consumption (VO2), and heart rate recovery between the two groups, nor were significant differences in pulmonary function identified. Within the PS group, there were no significant differences in MET, peak VO2, and heart rate recovery between the baseline and final CPET. Similarly, no significant differences were observed between the baseline and final PAV. The exercise capacity of patients with properly managed PS was comparable to that of healthy individuals. However, during the follow-up, declining trends in pulmonary function, aerobic metabolism, and peak exercise load capacity were observed among adolescents with PS. This study provides long-term data suggesting that PS patients should be encouraged to perform physical activity. Regular reevaluation should also be encouraged to limit performance deterioration.

INFLUÊNCIAS DO TÊNIS NA SAÚDE FÍSICA DAS UNIVERSITÁRIAS

ABSTRACT Introduction: Tennis is a confrontational sport that combines aerobic exercise with anaerobic exercise. Long-duration tennis can significantly improve female college students' physical qualities, such as strength, flexibility, sensitivity, and endurance, and help improve their physical health. Objective: Verify tennis's influences on female college students' physical health through long-duration tennis training. Methods: This paper aims to explore the influence of tennis on college students' physical health to provide some theoretical basis and practical guidance for colleges and universities to conduct tennis elective courses. Results: The elective tennis course has a good influence on the body shape of female college students. Conclusion: The university students' vital and aerobic metabolic capacity were significantly improved, and cardiac function was effectively benefited. The sport of tennis promotes blood flow and improves cardiopulmonary function. An influence on the height of female college students was not found. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.

A comparative and ontogenetic examination of mitochondrial function in Antarctic notothenioid species

Notothenioidei fishes have evolved under stable cold temperatures; however, ocean conditions are changing globally, with polar regions poised to experience the greatest changes in environmental factors, such as warming. These stressors have the potential to dramatically affect energetic demands, and the persistence of the notothenioids will be dependent on metabolic capacity, or the ability to match energy supply with energy demand, to restore homeostasis in the face of changing climate conditions. In this study we examined aerobic metabolic capacity in three species, Trematomus bernacchii, T. pennellii and T. newnesi, and between two life stages, juvenile and adult, by assessing mitochondrial function of permeabilized cardiac fibers. Respiratory capacity differed among the adult notothenioids in this study, with greater oxidative phosphorylation (OXPHOS) respiration in the pelagic T. newnesi than the benthic T. bernacchii and T. pennellii. The variation in mitochondrial respiratory capacity was likely driven by differences in the mitochondrial content, as measured by citrate synthase activity, which was the highest in T. newnesi. In addition to high OXPHOS, T. newnesi exhibited lower LEAK respiration, resulting in greater mitochondrial efficiency than either T. bernacchii or T. pennellii. Life stage largely had an effect on mitochondrial efficiency and excess complex IV capacity, but there were little differences in OXPHOS respiration and electron transfer capacity, pointing to a lack of significant differences in the metabolic capacity between juveniles and adults. Overall, these results demonstrate species-specific differences in cardiac metabolic capacity, which may influence the acclimation potential of notothenioid fishes to changing environmental conditions.

Transcriptomes Suggest That Pinniped and Cetacean Brains Have a High Capacity for Aerobic Metabolism While Reducing Energy-Intensive Processes Such as Synaptic Transmission.

The mammalian brain is characterized by high energy expenditure and small energy reserves, making it dependent on continuous vascular oxygen and nutritional supply. The brain is therefore extremely vulnerable to hypoxia. While neurons of most terrestrial mammals suffer from irreversible damage after only short periods of hypoxia, neurons of the deep-diving hooded seal (Cystophora cristata) show a remarkable hypoxia-tolerance. To identify the molecular mechanisms underlying the intrinsic hypoxia-tolerance, we excised neurons from the visual cortices of hooded seals and mice (Mus musculus) by laser capture microdissection. A comparison of the neuronal transcriptomes suggests that, compared to mice, hooded seal neurons are endowed with an enhanced aerobic metabolic capacity, a reduced synaptic transmission and an elevated antioxidant defense. Publicly available whole-tissue brain transcriptomes of the bowhead whale (Balaena mysticetus), long-finned pilot whale (Globicephala melas), minke whale (Balaenoptera acutorostrata) and killer whale (Orcinus orca), supplemented with 2 newly sequenced long-finned pilot whales, suggest that, compared to cattle (Bos taurus), the cetacean brain also displays elevated aerobic capacity and reduced synaptic transmission. We conclude that the brain energy balance of diving mammals is preserved during diving, due to reduced synaptic transmission that limits energy expenditure, while the elevated aerobic capacity allows efficient use of oxygen to restore energy balance during surfacing between dives.

The influence of sports tourism on the indicators of the cardiovascular system and coordination among students aged 16-18

The article deals with the processes of the work of the heart muscle and active muscles of the body of students aged 16-18 under the influence of cycling tourism. The purpose. To determine changes in the cardiovascular system and coordination of movements of 16-18 years old after the planned physical activity. Result. The data of 16-18 year old students on changes in diastolic blood pressure, heart rate, aerobic and anaerobic metabolic capacities, PWC170 test (p<0,05-0,001) are presented. Coordination capabilities in terms of walking on an 8-meter bench, the difference between running 15 m and slalom running 15 m, shuttle running, statistical balance with eyes closed, standing on the bike did not change (p>0,05). This suggests that there is a need in training to pay more attention to exercises for the development of coordination of movements.

Aerobic scope is not maintained at low temperature and is associated with cardiac aerobic capacity in the three-spined stickleback Gasterosteus aculeatus.

Metabolic thermal plasticity is central to the survival of fishes in a changing environment. The eurythermal three-spined stickleback Gasterosteus aculeatus displays thermal plasticity at the cellular level with an increase in the activity of key metabolic enzymes in response to cold acclimation. Nonetheless, it is unknown if these changes are sufficient to completely compensate for the depressive effects of cold temperature on whole organismal metabolic rate (ṀO2 ). The authors hypothesized that as a cold-tolerant, eurythermal fish, absolute aerobic scope (AAS), the difference between the maximum metabolic rate (MMR) and standard metabolic rate (SMR), would be maintained in G. aculeatus following acclimation to a range of temperatures that span its habitat temperatures. To test this hypothesis, G. aculeatus were acclimated to 5, 12 and 20°C for 20-32 weeks, and SMR, MMR and aerobic scope (AS) were quantified at each acclimation temperature. The maximal activity of citrate synthase (CS), a marker enzyme of aerobic metabolism, was also quantified in heart ventricles to determine if cardiac aerobic capacity is associated with AS at these temperatures. SMR increased with acclimation temperature and was significantly different among all three temperature groups. MMR was similar between animals at 5 and 12°C and between animals at 12 and 20°C but was 2.6-fold lower in fish at 5°C compared with those at 20°C, resulting in a lower AAS in fish at 5°C compared with those at 12 and 20°C. Correlated with a higher AAS in animals acclimated to 12 and 20°C was a larger relative ventricular mass and higher CS activity per 100 g body mass compared with animals at 5°C. Together, the results indicate that despite their eurythermal nature, AS is not maintained at low temperature but is associated with cardiac aerobic metabolic capacity.

Thermal tolerance, metabolic scope and performance of meagre, Argyrosomus regius, reared under high water temperatures.

This article reports on the thermal tolerance, metabolic capacity and performance of juvenile meagre (Argyrosomus regius) reared under three high water temperatures (24, 29 and 34°C) for three months. The analysis includes the thermal effects on the growth performance, metabolism and physiology of meagre, including a range of molecular, haematological, metabolic, enzymatic and hormonal indicators, as well as the effects on the proximate composition and ingestion speed. Meagre performs best between 24 and 29°C while the temperature of 34°C is very close to the upper end of its temperature tolerance range. At 34°C meagre exhibits a poor growth performance and physiological status, increased blood clotting, high mortality rates and a diminished capacity for aerobic metabolism, as indicated by its low aerobic scope (129mgkg-1 h-1). Meagre may tolerate short exposures to high temperatures after sufficient acclimation (Critical thermal maximum of 37.5°C after acclimation to 29°C) but its overall performance declines under prolonged exposure, suggesting that this emerging aquaculture species may be vulnerable to global warming. Our work corroborates previous findings on the thermal preferences of the species, identifies critical biological thresholds, and provides insights into the effects of prolonged exposure to high temperature regimes.

Оцінка рівня функціонального стану і протікання специфічного біологічного циклу велосипедисток та спортсменок вільної боротьби 15-16 років

Purpose: to determine the functioning of the cardiovascular and reproductive system of cyclists and wrestlers 15-16 years under the influence of specific physical activity. Material and methods. 14 athletes took part in the research, 7 of them were freestyle wrestling (3 – I category, 4 – candidates for master of sports) and 7 – Mountain Bike (MTO) races (4 – I category, 3 – candidates for master of sports). Research methods: theoretical analysis and generalization of scientific and methodological literature, pedagogical and biomedical research methods, methods of mathematical statistics. Results: the analysis of educational programs (freestyle wrestling, cycling-MTV) of the age group of 15-16 years showed that in these kinds of sports a different mode of educational and training work during the annual cycle. So, for freestyle wrestling athletes in the age group 15-16 years old, special physical training is planned for 100 hours, psychological training for 20 hours, competitive training for 42 hours, for 70 hours – rehabilitation means for 6 hours – medical control, while female cyclists – MTB is 12 hours more than general physical training, 144 hours more – technical and tactical. After the training year, the analysis of the trainers' plans showed that in freestyle wrestling, the percentage of general physical training has changed and amounted to 16 %, special physical – 24 %, technical and tactical – 33 %, psychological – 4 %, while in cycling general physical training – 19 %, special physical – 25 %, technical and tactical – 34 %, psychological – 6 %. Special and technical-tactical work by 1 % and psychological work by 2 % more were performed by cyclists relative to wrestlers. Comparison of the indicators of the cardiovascular system of female athletes showed a statistical difference in systolic blood pressure (t=3,60; t=8,92; p<0,001), in diastolic blood pressure (t=3,56; t=6,00, p<0,001), in the aerobic metabolic capacity (t=5,08; t=7,07; p<0,001), in the anaerobic metabolic capacity (t=12,20; t=8,14; p<0,001). According to a survey of female athletes, it was determined that in September 2019, 33 % of athletes 15-16 years old had irregular menstruation and 67% – regular, in December 2019 4 3% – irregular and 57 % – regular, in May 2020 50% – irregular and 50 % – regular, in September 2020 57 % – irregular and 43 % – regular menstruation. Conclusions. The analysis of curricula for the chosen sport and training plans of coaches by types of training showed that the specificity of the training process is the specificity of the discipline in which relatively independent types are clearly visible, and the distribution of training and competitive physical loads is interconnected with the stage of training. Comparison of the indicators of the cardiovascular system of female athletes 15-16 years old showed that higher performance in cyclists as a result of training (physiologically athletic heart. At the same time, among wrestlers it was recognized as more optimal indicators of the heart muscle for further improvement of sportsmanship. The negative dynamics of the ovarian cycle at the age of 15-16 years was determined, which amounted to 21 % of irregular menstruation. Keywords: freestyle wrestling, cycling-MTB, specific biological cycle, cardiovascular system.

Wild longnose dace downstream of wastewater treatment plants display an obese phenotype

Wild fish living downstream of wastewater treatment plants (WWTPs) often have increased body condition factors or body mass indices compared to upstream fish. This observation has been largely attributed to increased nutrient loading and food availability around wastewater effluent outflows. While a higher condition factor in fish is generally considered a predictor of healthy ecosystems, the metabolic status and capacity of the animals downstream of WWTPs may be a better predictor of fitness and potential population level effects. To address this, we sampled wild longnose dace (Rhinichthys cataractae), a native species in North American waterways, from sites upstream and downstream of WWTPs. Downstream fish had higher body mass indices, which corresponded with higher nutrient (lipid, protein, and glycogen) storage in somatic tissues compared to upstream fish. Liver transcriptome analysis revealed metabolic reprogramming favoring lipid synthesis, including higher hepatic triglyceride levels and transcript abundance of targeted lipogenic genes. This suggests that effluent exposure-mediated obesity in dace is a result of changes at the transcriptional level. To determine potential ecological consequences, we subjected these fish to an acute stressor in situ to determine their stress performance. Downstream fish failed to mobilize metabolites post-stress, and showed a reduction in liver aerobic and anaerobic metabolic capacity. Taken together, fish living downstream of WWTPs exhibit a greater lipid accumulation that results in metabolic disruption and may compromise the ability of these fish to cope with subsequent environmental and/or anthropogenic stressors.

Effects of Intertidal Position on Metabolism and Behavior in the Acorn Barnacle, Balanus glandula.

The intertidal zone is characterized by persistent, tidally-driven fluctuations in both abiotic (e.g., temperature, oxygen, and salinity) and biotic (e.g., food availability and predation) factors, which make this a physiologically challenging habitat for resident organisms. The relative magnitude and degree of variability of environmental stress differ between intertidal zones, with the most extreme physiological stress often being experienced by organisms in the high intertidal. Given that so many of the constantly shifting parameters in this habitat are primary drivers of metabolic rate (e.g., temperature, [O2], and food availability), we hypothesized that sessile conspecifics residing in different tidal zones would exhibit distinct “metabolic phenotypes,” a term we use to collectively describe the organisms’ baseline metabolic performance and capacity. To investigate this hypothesis, we collected acorn barnacles (Balanus glandula) from low, mid, and high intertidal positions in San Luis Obispo Bay, CA, and measured a suite of biochemical (whole-animal citrate synthase (CS) and lactate dehydrogenase (LDH) activity, and aerial [D-lactate]), physiological (O2 consumption rates), morphological (body size), and behavioral (e.g., cirri beat frequency and percentage of time operculum open) indices of metabolism. We found tidal zone-dependent differences in B. glandula metabolism that primarily related to anaerobic capacity, cirral activity patterns, and body size. Barnacles from the low intertidal tended to have a greater capacity for anaerobic metabolism (i.e., increased LDH activity and increased baseline [D-lactate]), have reduced cirral beating activity—and presumably reduced feeding—when submerged, and be smaller in size compared to conspecifics in the high intertidal. We did not, however, see any D-lactate accumulation in barnacles from any tidal height throughout 96 h of air exposure. This trend indicates that the enhanced capacity of low intertidal barnacles for anaerobic metabolism may have evolved to support metabolism during more prolonged episodes of emersion or during events other than emersion (e.g., coastal hypoxia and predation). There were also no significant differences in CS activity or baseline O2 consumption rates (in air or seawater at 14°C) across tidal heights, which imply that aerobic metabolic capacity may not be as sensitive to tidal position as anaerobic processes. Understanding how individuals occupying different shore heights differ in their metabolic capacity becomes increasingly interesting in the context of global climate change, given that the intertidal zone is predicted to experience even greater extremes in abiotic stress.

Applications of the Critical Power Model to Dynamic Constant External Resistance Exercise: A Brief Review of the Critical Load Test

The study and application of the critical power (CP) concept has spanned many decades. The CP test provides estimates of two distinct parameters, CP and W′, that describe aerobic and anaerobic metabolic capacities, respectively. Various mathematical models have been used to estimate the CP and W′ parameters across exercise modalities. Recently, the CP model has been applied to dynamic constant external resistance (DCER) exercises. The same hyperbolic relationship that has been established across various continuous, whole-body, dynamic movements has also been demonstrated for upper-, lower-, and whole-body DCER exercises. The asymptote of the load versus repetition relationship is defined as the critical load (CL) and the curvature constant is L′. The CL and L′ can be estimated from the same linear and non-linear mathematical models used to derive the CP. The aims of this review are to (1) provide an overview of the CP concept across continuous, dynamic exercise modalities; (2) describe the recent applications of the model to DCER exercise; (3) demonstrate how the mathematical modeling of DCER exercise can be applied to further our understanding of fatigue and individual performance capabilities; and (4) make initial recommendations regarding the methodology for estimating the parameters of the CL test.

Bisphenols alter thermal responses and performance in zebrafish (Danio rerio).

Plastic pollutants are novel environmental stressors that are now persistent components of natural ecosystems. Endocrine disrupting chemicals such as bisphenols that leach out of plastics can modify physiological responses of animals by interfering with hormone signalling. Here, we tested whether three commonly produced bisphenols, bisphenol A (BPA), bisphenol F (BPF) and bisphenol S (BPS), impair thermal acclimation of swimming performance and metabolic enzyme [citrate synthase (CS) and lactate dehydrogenase (LDH)] activities in adult zebrafish (Danio rerio). We found that exposure to 30-μgl-1 BPF and BPS, but not BPA, reduced swimming performance, and no interactions between bisphenol exposure and acclimation (3weeks to 18°C and 28°C) or acute test (18°C and 28°C) temperatures were found. BPA interacted with acclimation and acute test temperatures to determine CS activity, an indicator of mitochondrial density and aerobic metabolic capacity. BPS reduced CS activity and an interaction (at a one-tailed significance) between acclimation temperature and BPF exposure determined CS activity. LDH activity reflects anaerobic ATP production capacity, and BPA and BPF altered the effects of thermal acclimation and acute test temperatures on LDH activity. Our data show that all bisphenols we tested at ecologically relevant concentrations can disrupt the thermal responses of fish. BPS and BPF are used as environmentally safer alternatives to BPA, but our data show that these bisphenols are also of concern, particularly in thermally variable environments.

Reduced growth may be linked to lower aerobic scope in juvenile triploid white sturgeon (Acipenser transmontanus)

Previous studies have provided evidence of a reduced aerobic metabolic capacity, both at the cellular (metabolic enzyme activity) and the whole organism (aerobic scope) level in juvenile triploid white sturgeon, compared to diploid siblings. The downstream costs of this reduced metabolic capacity are still unclear, yet a lower aerobic scope suggests triploid white sturgeon likely have less energy to allocate to biological processes like growth and development. We conducted a 15-week growth trial to assess energy allocation to somatic growth in 2-month-old diploid and triploid white sturgeon. Spontaneous swimming activity, hepatosomatic index, condition factor, and deformities were also measured throughout the growth trial as indices of energy allocation to activity and fish condition. In general, our results indicate that triploid white sturgeon may have less energy available for processes beyond basal maintenance. This could be linked to a reduced overall performance as evidenced by lower weights and more deformities when compared with their diploid counterparts. However, many indices were still mostly unaffected by triploidy (condition factor, hepatosomatic index, and swimming activity). Whether this lower growth performance seen in juvenile triploid white sturgeon continues through sub-adulthood, puberty and final maturation requires further long-term studies.

Patients with Kawasaki Disease Have Significantly Low Aerobic Metabolism Capacity and Peak Exercise Load Capacity during Adolescence.

Introduction: Kawasaki disease (KD) is a childhood illness causing blood vessel inflammation. Children with KD have similar cardiopulmonary function to healthy children, but lower moderate-to-vigorous activity and exercise self-efficacy—possibly harming their cardiopulmonary function in adolescence. The purpose of this study is to investigate the cardiopulmonary function, exercise behaviors, exercise motivations, and self-efficacy of adolescents who once had KD. Methods: adolescents who once had KD and adolescents matched to the KD group in age and sex were enrolled. The cardiopulmonary exercise test was used to assess cardiopulmonary function. Weekly exercise behavior, exercise motivation, and self-efficacy were assessed with questionnaires. Results: this study recruited 50 and 30 participants, respectively, to the KD and control groups. The KD group had a lower ratio of VO2/kg at the anaerobic threshold and peak to the predicted VO2/kg at the peak (p = 0.021 and 0.043, respectively). No significant differences were found in questionnaire scores. The correlations of weekly exercise behavior scores with exercise motivation and self-efficacy scores were stronger in the KD group. Conclusions: adolescents with KD history had significantly lower aerobic metabolism capacity and peak exercise load capacity than controls. The correlations of amount of weekly exercise with exercise motivation and self-efficacy were stronger in the KD group.