Search results for "oxygen consumption"
showing 10 items of 347 documents
Alternative respiratory pathways of Escherichia coli: energetics and transcriptional regulation in response to electron acceptors
1997
AbstractThe electron-transport chains of Escherichia coli are composed of many different dehydrogenases and terminal reductases (or oxidases) which are linked by quinones (ubiquinone, menaquinone and demethylmenaquinone). Quinol:cytochrome c oxido-reductase (`bc1 complex') is not present. For various electron acceptors (O2, nitrate) and donors (formate, H2, NADH, glycerol-3-P) isoenzymes are present. The enzymes show great variability in membrane topology and energy conservation. Energy is conserved by conformational proton pumps, or by arrangement of substrate sites on opposite sides of the membrane resulting in charge separation. Depending on the enzymes and isoenzymes used, the H+/e− rat…
Altered Mitochondrial Function and Oxidative Stress in Leukocytes of Anorexia Nervosa Patients
2014
ContextAnorexia nervosa is a common illness among adolescents and is characterised by oxidative stress.ObjectiveThe effects of anorexia on mitochondrial function and redox state in leukocytes from anorexic subjects were evaluated.Design and settingA multi-centre, cross-sectional case-control study was performed.PatientsOur study population consisted of 20 anorexic patients and 20 age-matched controls, all of which were Caucasian women.Main outcome measuresAnthropometric and metabolic parameters were evaluated in the study population. To assess whether anorexia nervosa affects mitochondrial function and redox state in leukocytes of anorexic patients, we measured mitochondrial oxygen consumpt…
The role of glutathione in protection against DNA damage induced by rifamycin SV and copper(II) ions.
1993
Incubation of calf thymus DNA in the presence of rifamycin SV induces a decrease in the absorbance of DNA at 260 nm. The effect, was found to be proportional to the antibiotic concentration and enhanced by copper(II) ions. In the presence of rifamycin SV and copper(II), a significant increase in thiobarbituric acid-reactive (TBA-reactive) material is also observed. This effect is inhibited to different degrees by the following antioxidants: catalase 77%; thiourea 72%; glutathione (GSH) 62%; ethanol 52%; and DMSO 34%, suggesting that both hydrogen peroxide (H2O2) and hydroxyl radicals (OH.) are involved in DNA damage. Rifamycin SV-copper(II) mixtures were also found to induce the production …
Effect of ADH II Deficiency on the Intracellular Redox Homeostasis in Zymomonas mobilis
2011
Mutant strain of the facultatively anaerobic, ethanol-producing bacteriumZymomonas mobilis, deficient in the Fe-containing alcohol dehydrogenase isoenzyme (ADH II), showed impaired homeostasis of the intracellular NAD(P)H during transition from anaerobic to aerobic conditions, and also in steady-state continuous cultures at various oxygen supplies. At the same time, ADH II deficiency in aerobically grown cells was accompanied by a threefold increase of catalase activity and by about 50% increase of hydrogen peroxide excretion. It is concluded that ADH II under aerobic conditions functions to maintain intracellular redox homeostasis and to protect the cells from endogenous hydrogen peroxide.
The association between body mass, metabolic rates and survival of bank voles
2009
Summary 1Many studies have been performed in an attempt to explain physiological, ecological and evolutionary factors behind inter- and intraspecific variation in basal metabolic rate (BMR) and maximum aerobic metabolic rate (VO2max). However, very little is known about the association between the traits and fitness components in populations of free-living animals. 2We studied the association between body size and the metabolic rates of bank voles Myodes (= Clethrionomys) glareolus and their survival, measured by repeated trappings across 2 years in an isolated, island population. All measured traits (body mass, BM; head width, HW; VO2max and BMR) were significantly repeatable over short (m…
Stable bioenergetic status despite substantial changes in blood flow and tissue oxygenation in a rat tumour.
1994
Experiments on s.c. rat tumours (DS sarcoma) were performed to determine whether chronic or acute changes in tumour perfusion necessarily lead to changes in tissue oxygenation and bioenergetic status since, as a rule, blood flow is thought to be the ultimate determinant of the tumour bioenergetic status. Based on this study, there is clear experimental evidence that growth-related or acute (following i.v. administration of tumour necrosis factor alpha) decreases in tumour blood flow are accompanied by parallel alterations in tissue oxygenation. In contrast, tumour energy status remains stable as long as flow values do not fall below 0.4-0.5 ml g-1 min-1, and provided that glucose as the mai…
Laser Doppler flux and tissue oxygenation of experimental tumours upon local hyperthermia and/or hyperglycaemia
1992
Laser Doppler fluxmetry and oxygen partial pressure (pO2) histography have been applied to investigate the acute effects of hyperthermia (HT) and/or hyperglycaemia (HG) on microcirculatory function and tissue oxygenation of subcutaneous rat tumours growing on the dorsum of the hind foot. The experiments were performed to test whether, and to what extent, the two adjunct treatment modalities applied alone or in combination can modify these therapeutically relevant parameters. Local HT was performed in a saline bath (44 degrees C) for 2 h; HG was induced by i.v. infusion of 40% glucose solution for 2.5 h (blood glucose levels: 35-40 mM during heating). Laser Doppler flux (LDF) in superficial …
Metabolic and cardiopulmonary effects of detraining after a structured exercise training programme in young PCOS women
2008
Summary Objective The aim of the present study was to determine if the favourable cardiopulmonary and metabolic benefits induced by exercise training (ET) programme are maintained after its cessation. Patients Thirty-two young overweight polycystic ovary syndrome (PCOS) women matched for age and body mass index (BMI) with other 32 PCOS patients was enrolled. The first group [PCOS-T (trained)] underwent 24-week ET programme, whereas the second [PCOS-DT (detrained)] underwent 12-week ET programme followed by 12-week detraining period. Methods At baseline, after 12- and 24-week follow-up, all PCOS women were studied for their hormonal (ovarian and adrenal androgens), metabolic (glucose and …
The effects of cold and glucagon on lipolysis, glycogenolysis and oxygen consumption in young chicks.
1973
Abstract 1. 1. To study the possible role of glucagon in avian thermoregulation the effects of cold exposure and glucagon on lipolysis, glycogenolysis and oxygen consumption were measured in young chicks. 2. 2. Cold exposure (+10°C) and glucagon injection (0·3 mg/kg, i.p. at +30°C) both caused a marked increase in the plasma FFA and a decrease in the liver glycogen content. 3. 3. It is suggested that glucagon possibly acts in the avian thermoregulation by producing at least lipolysis and glycogenolysis during cold exposure.
Effects Of Combined Strength And Endurance Training On Physical Performance And Biomarkers Of Healthy Young Women
2018
Kyröläinen, H, Hackney, AC, Salminen, R, Repola, J, Häkkinen, K, and Haimi, J. Effects of combined strength and endurance training on physical performance and biomarkers of healthy young women. J Strength Cond Res 32(6): 1554– 1561, 2018—Cardiovascular fitness has decreased and obesity has increased in young adults worldwide during the last 10 years. Therefore, there is an urgent need to find out optimal exercise training programs for improving physical performance and health outcomes, especially among sedentary women. Subjects were 25- to 30-year-old women with a very low physical activity, and 65% of them were overweight (body mass index . 25). They performed endurance and strength traini…