Effects of 5-bromo-2′-deoxyuridine on Friend erythroleukaemia cells. II. Oxidative metabolism and enzyme content of whole cells and isolated mitochondria

1981 ◽  
Vol 52 (1) ◽  
pp. 37-54
Author(s):  
R.J. Walter
Keyword(s):  
Oxygen Consumption ◽  
Respiratory Control ◽  
High Energy ◽  
Inhibitory Effect ◽  
Mitochondrial Enzymes ◽  
Morphological Alterations ◽  
Isolated Mitochondria ◽  
Outer Compartment ◽  
Consumption Rates ◽  
Electrode Chamber

Untreated or bromodeoxyuridine (BrdUrd)-treated Friend erythroleukaemia (EL) cells from 15- and 72-h-cultures were harvested and the mitochondria were isolated by homogenization and differential centrifugation. Aliquots of the original cell suspensions or the final mitochondrial suspensions were either fixed for electron microscopy, assayed for enzyme activities, or introduced into a 1-ml Clarke oxygen electrode chamber. Whole BrdUrd-treated cells exhibited notable morphological alterations (see accompanying paper) but no effect was observed on whole-cell respiration. Morphologically, isolated mitochondria exhibited a highly condensed matrix and a greatly expanded outer compartment. Functionally, these mitochondria oxidized a variety of substrates at high state-3 (ADP-stimulated) rates (60-210 ng atoms O/min per mg protein) and displayed adequate respiratory control and ADP/O ratios. In the mitochondria isolated from BrdUrd-treated EL cells (both 15- and 72-h cultures), the state-3 oxygen consumption rates, respiratory control ratios, and ADP/O ratios generally decreased compared to their matched controls. These functional deficiencies coincided with in situ increases in the volume of the mitochondrial compartment and conspicuous (30-100%) increases in the specific and total activities of several mitochondrial enzymes. In addition, the mitochondria isolated from the 72-h group (treated and untreated) displayed immediate alterations when BrdUrd was added to the electrode chamber. Oxygen consumption rates dropped, respiratory control ratios changed moderately, and ADP/O ratios increased. BrdUrd may act both as an inhibitor of oxidative phosphorylation and perhaps as a sink for some of the high energy phosphate that is being generated. Thus, BrdUrd may exert its inhibitory effect on cell differentiation by interfering with mitochondrial function.

scholarly journals REDUCED CITRATE SYNTHASE ACTIVITY EFFECT ON OXYGEN CONSUMPTION RATES IN ISOLATED MITOCHONDRIA FROM MICE LIVER AND MUSCLES

2016 ◽  
Vol 2 (101) ◽  
pp. 26-30
Author(s):  
Andrej Fokin ◽  
Rasa Žūkienė ◽  
Aivaras Ratkevičius
Keyword(s):  
Oxygen Consumption ◽  
Mitochondrial Respiration ◽  
Skeletal Muscles ◽  
Citrate Synthase ◽  
Oxygen Electrode ◽  
Isolated Mitochondria ◽  
Activity Effect ◽  
Consumption Rates ◽  
Centrifugation Method ◽  
Mice Liver

Background. Liver and skeletal muscles play the major role in metabolism. Mitochondria are of particular importance in functioning of these organs. We tested the hypothesis that reduced citrate synthase (CS) activity could induce improved fatty substrate and carbohydrate oxidation in mitochondria extracted from liver and hind limb muscles of mice. Methods. Eight mice each of 12-week-old control C57B6/J (B6) and congenic B6.A-(rs3676616-D10Utsw1)/ Kjn (B6.A) mice were studied. The mitochondria were isolated by differential centrifugation method followed by assessment of mitochondrial respiration and citrate synthase (CS) activity. Mitochondrial respiration was measured as oxygen consumption with Clark-type oxygen electrode by using polarography system. CS enzyme activity was measured spectrophotometrically. Results. The activity of CS was by ~32% lower for mitochondria for B6.A compared to B6 mice (603.9 ± 135.6 U/g and 894.2 ± 193.2 U/g, respectively). Mitochondrial respiration did not differ significantly between the strains. Conclusions. 30% reduction in citrate synthase activity does not impair mitochondrial respiration.

Letters to the Editor

1998 ◽  
Vol 275 (2) ◽  
pp. H726-H729
Author(s):  
J. A. L. Jeneson ◽  
M. J. Kushmerick ◽  
H. V. Westerhoff
Keyword(s):  
Oxygen Consumption ◽  
Steady State ◽  
Western Blot ◽  
Northern Blot ◽  
Adenine Nucleotide ◽  
Respiratory Control ◽  
High Energy ◽  
High Energy Phosphates ◽  
Adenine Nucleotide Translocator

The following is the abstract of the article discussed in the subsequent letter: Portman, Michael A., Yun Xiao, Ying Song, and Xue-Han Ning. Expression of adenine nucleotide translocator parallels maturation of respiratory control in heart in vivo. Am. J. Physiol. 273 ( Heart Circ. Physiol. 42): H1977–H1983, 1997.—Changes in the relationship between myocardial high-energy phosphates and oxygen consumption in vivo occur during development, implying that the mode of respiratory control undergoes maturation. We hypothesized that these maturational changes in sheep heart are paralleled by alterations in the adenine nucleotide translocator (ANT), which are in turn related to changes in the expression of this gene. Increases in myocardial oxygen consumption (MV˙o 2) were induced by epinephrine infusion in newborn (0–32 h, n = 6) and mature sheep (30–32 days, n = 6), and high-energy phosphates were monitored with 31P nuclear magnetic resonance. Western blot analyses for the ANT1 and the β-subunit of F1-adenosinetriphosphatase (ATPase) were performed in these hearts and additional ( n = 9 total per group) as well as in fetal hearts (130–132 days of gestation, n = 5). Northern blot analyses were performed to assess for changes in steady-state RNA transcripts for these two genes. Kinetic analyses for the31P spectra data revealed that the ADP-MV˙o 2 relationship for the newborns conformed to a Michaelis-Menten model but that the mature data did not conform to first- or second-order kinetic control of respiration through ANT. Maturation from fetal to mature was accompanied by a 2.5-fold increase in ANT protein (by Western blot), with no detectable change in β-F1-ATPase. Northern blot data show that steady-state mRNA levels for ANT and β-F1-ATPase increased ∼2.5-fold from fetal to mature. These data indicate that 1) respiratory control pattern in the newborn is consistent with a kinetic type regulation through ANT, 2) maturational decreases in control through ANT are paralleled by specific increases in ANT content, and 3) regulation of these changes in ANT may be related to increases in steady-state transcript levels for its gene.

Expression of adenine nucleotide translocator parallels maturation of respiratory control in heart in vivo

1997 ◽  
Vol 273 (4) ◽  
pp. H1977-H1983 ◽  
Author(s):  
Michael A. Portman ◽  
Yun Xiao ◽  
Ying Song ◽  
Xue-Han Ning
Keyword(s):  
Oxygen Consumption ◽  
Steady State ◽  
Western Blot ◽  
Northern Blot ◽  
Adenine Nucleotide ◽  
Respiratory Control ◽  
High Energy ◽  
High Energy Phosphates ◽  
Adenine Nucleotide Translocator

Changes in the relationship between myocardial high-energy phosphates and oxygen consumption in vivo occur during development, implying that the mode of respiratory control undergoes maturation. We hypothesized that these maturational changes in sheep heart are paralleled by alterations in the adenine nucleotide translocator (ANT), which are in turn related to changes in the expression of this gene. Increases in myocardial oxygen consumption (MV˙o 2) were induced by epinephrine infusion in newborn (0–32 h, n = 6) and mature sheep (30–32 days, n = 6), and high-energy phosphates were monitored with 31P nuclear magnetic resonance. Western blot analyses for the ANT1 and the β-subunit of F1-adenosinetriphosphatase (ATPase) were performed in these hearts and additional ( n = 9 total per group) as well as in fetal hearts (130–132 days of gestation, n = 5). Northern blot analyses were performed to assess for changes in steady-state RNA transcripts for these two genes. Kinetic analyses for the31P spectra data revealed that the ADP-MV˙o 2 relationship for the newborns conformed to a Michaelis-Menten model but that the mature data did not conform to first- or second-order kinetic control of respiration through ANT. Maturation from fetal to mature was accompanied by a 2.5-fold increase in ANT protein (by Western blot), with no detectable change in β-F1-ATPase. Northern blot data show that steady-state mRNA levels for ANT and β-F1-ATPase increased ∼2.5-fold from fetal to mature. These data indicate that 1) respiratory control pattern in the newborn is consistent with a kinetic type regulation through ANT, 2) maturational decreases in control through ANT are paralleled by specific increases in ANT content, and 3) regulation of these changes in ANT may be related to increases in steady-state transcript levels for its gene.

Effect of prior exercise and insulin on potential thermogenic systems in rat skeletal muscle

1992 ◽  
Vol 72 (6) ◽  
pp. 2203-2209 ◽  
Author(s):  
T. W. Balon ◽  
J. L. Treadway ◽  
J. B. Hughes ◽  
J. C. Young ◽  
N. B. Ruderman
Keyword(s):  
Skeletal Muscle ◽  
Oxygen Consumption ◽  
Respiratory Control ◽  
Creatine Phosphate ◽  
High Energy ◽  
Transport Systems ◽  
Mitochondrial Uncoupling ◽  
Skeletal Muscle Mitochondria ◽  
Prior Exercise ◽  
Fructose 1,6 Bisphosphate

We previously reported that insulin stimulates oxygen consumption by the perfused rat hindquarter after high-intensity exercise. The purpose of the present study was to examine whether fructose 6-phosphate-fructose 1,6-bisphosphate cycling or an uncoupling of mitochondrial respiration contributes to this phenomenon. Hindquarter skeletal muscle was analyzed after perfusion in the absence or presence of insulin (150–200 microU/ml) for high-energy phosphate content, fructose 6-phosphate-fructose 1,6-bisphosphate cycling of glucose before incorporation into glycogen, and mitochondrial respiratory control. Muscle from exercised rats perfused with insulin did not display greater rates of glucose cycling or mitochondrial uncoupling; in fact, insulin decreased the rate of fructose 6-phosphate cycling and tended to increase respiratory control in skeletal muscle mitochondria. In addition, the concentrations of ATP and creatine phosphate and the calculated free ADP level in muscle of previously exercised rats perfused with insulin were similar to those of control rats. The results do not exclude the possibility that localized subcellular changes in ADP occurred, however. In conclusion, the results suggest that insulin-induced increases in other substrate cycles, ion transport systems, and/or as yet unidentified energy-requiring processes account for the 25–30% increase in hindquarter oxygen consumption after intense exercise.

scholarly journals Oxygen consumption rates in subseafloor basaltic crust derived from a reaction transport model

2013 ◽  
Vol 4 (1) ◽  
Author(s):  
Beth N. Orcutt ◽  
C. Geoffrey Wheat ◽  
Olivier Rouxel ◽  
Samuel Hulme ◽  
Katrina J. Edwards ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Transport Model ◽  
Consumption Rates ◽  
Reaction Transport ◽  
Basaltic Crust

The Relation of Oxygen Consumption to Body Size and to Temperature in the Larvae of Chironomus Riparius Meigen

1958 ◽  
Vol 35 (2) ◽  
pp. 383-395
Author(s):  
R. W. EDWARDS
Keyword(s):  
Oxygen Consumption ◽  
Body Size ◽  
Dry Matter ◽  
Larval Instar ◽  
Weight Ratio ◽  
Dry Weight ◽  
Chironomus Riparius ◽  
Consumption Rates ◽  
Rate Of Oxygen Consumption ◽  
Wet Weight

1. The oxygen consumption rates of 3rd- and 4th-instar larvae of Chironomus riparius have been measured at 10 and 20° C. using a constant-volume respirometer. 2. The oxygen consumption is approximately proportional to the 0.7 power of the dry weight: it is not proportional to the estimated surface area. 3. This relationship between oxygen consumption and dry weight is the same at 10 and at 20° C.. 4. The rate of oxygen consumption at 20° C. is greater than at 10° C. by a factor of 2.6. 5. During growth the percentage of dry matter of 4th-instar larvae increases from 10 to 16 and the specific gravity from 1.030 to 1.043. 6. The change in the dry weight/wet weight ratio during the 4 larval instar supports the theory of heterauxesis. 7. At 20° C., ‘summer’ larvae respire faster than ‘winter’ larvae.

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