Physiological diversity of mitochondrial oxidative phosphorylation

2006 ◽  
Vol 291 (6) ◽  
pp. C1172-C1182 ◽  
Author(s):  
G. Benard ◽  
B. Faustin ◽  
E. Passerieux ◽  
A. Galinier ◽  
C. Rocher ◽  
...  
Keyword(s):  
Oxidative Phosphorylation ◽  
Respiratory Chain ◽  
Citrate Synthase ◽  
Intrinsic Activity ◽  
Mitochondrial Oxidative Phosphorylation ◽  
Respiratory Chain Complexes ◽  
Mitochondrial Content ◽  
Physiological Diversity ◽  
Chain Complexes ◽  
Functional Features

To investigate the physiological diversity in the regulation and control of mitochondrial oxidative phosphorylation, we determined the composition and functional features of the respiratory chain in muscle, heart, liver, kidney, and brain. First, we observed important variations in mitochondrial content and infrastructure via electron micrographs of the different tissue sections. Analyses of respiratory chain enzyme content by Western blot also showed large differences between tissues, in good correlation with the expression level of mitochondrial transcription factor A and the activity of citrate synthase. On the isolated mitochondria, we observed a conserved molar ratio between the respiratory chain complexes and a variable stoichiometry for coenzyme Q and cytochrome c, with typical values of [1–1.5]:[30–135]:[3]:[9–35]:[6.5–7.5] for complex II:coenzyme Q:complex III:cytochrome c:complex IV in the different tissues. The functional analysis revealed important differences in maximal velocities of respiratory chain complexes, with higher values in heart. However, calculation of the catalytic constants showed that brain contained the more active enzyme complexes. Hence, our study demonstrates that, in tissues, oxidative phosphorylation capacity is highly variable and diverse, as determined by different combinations of 1) the mitochondrial content, 2) the amount of respiratory chain complexes, and 3) their intrinsic activity. In all tissues, there was a large excess of enzyme capacity and intermediate substrate concentration, compared with what is required for state 3 respiration. To conclude, we submitted our data to a principal component analysis that revealed three groups of tissues: muscle and heart, brain, and liver and kidney.

Brain energy metabolism is increased by chronic administration of bupropion

2012 ◽  
Vol 24 (2) ◽  
pp. 115-121 ◽  
Author(s):  
Gabriela K. Ferreira ◽  
Gislaine T. Rezin ◽  
Mariane R. Cardoso ◽  
Cinara L. Gonçalves ◽  
Lislaine S. Borges ◽  
...  
Keyword(s):  
Energy Metabolism ◽  
Malate Dehydrogenase ◽  
Respiratory Chain ◽  
Citrate Synthase ◽  
Chronic Administration ◽  
Mitochondrial Respiratory Chain ◽  
Brain Energy Metabolism ◽  
Respiratory Chain Complexes ◽  
Chain Complexes ◽  
Brain Energy

Objectives: Based on the hypothesis that energy impairment may be involved in the pathophysiology of depression, we evaluated the activities of citrate synthase, malate dehydrogenase, succinate dehydrogenase (SDH), mitochondrial respiratory chain complexes I, II, II-III, IV and creatine kinase (CK) in the brain of rats submitted to chronic administration of bupropion.Methods: Animals received daily administration of bupropion dissolved in saline (10 mg/kg, intraperitoneal) at 1.0 ml/kg body weight. The rats received injections once a day for 14 days; control rats received an equivalent volume of saline. Twelve hours after the last administration, the rats were killed by decapitation and brain was rapidly removed and kept on an ice plate. The activities of the enzymes were measured in different brain areas.Results: We observed that the activities of citrate synthase and malate dehydrogenase, mithocondrial respiratory chain complexes I, II-III and IV and CK were not altered after chronic administration of bupropion. However, SDH activity was increased in the prefrontal cortex and cerebellum. In the hippocampus, cerebellum and striatum the activity of complex II was increased after chronic administration of bupropion.Conclusions: Our results demonstrated that bupropion increased some enzymes of brain energy metabolism. These findings are in accordance with other studies which showed that some antidepressants may improve energy metabolism. The present results reinforce the hypothesis that antidepressants modulate brain energy metabolism.

scholarly journals Activity of Mitochondrial Respiratory Chain Enzymes after Transient Focal Ischemia in the Rat

1997 ◽  
Vol 17 (11) ◽  
pp. 1166-1169 ◽  
Author(s):  
Laura Canevari ◽  
Satoshi Kuroda ◽  
Timothy E. Bates ◽  
John B. Clark ◽  
Bo K. Siesjö
Keyword(s):  
Respiratory Chain ◽  
Citrate Synthase ◽  
Mitochondrial Respiratory Chain ◽  
Artery Occlusion ◽  
Respiratory Chain Complexes ◽  
Secondary Damage ◽  
Chain Complexes ◽  
Postischemic Recirculation ◽  
Transient Focal Ischemia ◽  
Mitochondrial Respiratory

Previous results demonstrated that after 2-hour middle cerebral artery occlusion (MCAO) in the rat, 1- to 2-hour recirculation temporarily restored the bioenergetic state and mitochondrial function, but secondary deterioration took place after 4 hours. The authors measured the activity of mitochondrial respiratory chain complexes, citrate synthase, and glutamate dehydrogenase as possible targets of secondary damage. Focal and penumbral tissues were sampled in the control condition, after 2 hours of MCAO, and after 1, 2, or 4 hours of postischemic recirculation; two groups were treated with α-phenyl-N- tert-butyl-nitrone (PBN). Complex IV activity transiently decreased after MCAO, but after recirculation all measured activities returned to control values.

Ultrastructural and functional abnormalities of mitochondria in cultivated fibroblasts from α-mannosidosis patients

Biologia ◽  
2009 ◽  
Vol 64 (2) ◽  
Author(s):  
Olga Brantova ◽  
Befekadu Asfaw ◽  
Jana Sladkova ◽  
Helena Poupetova ◽  
Jan Zivny ◽  
...  
Keyword(s):  
Respiratory Chain ◽  
Energy Demand ◽  
Citrate Synthase ◽  
Chain Complex ◽  
Lysosomal Storage ◽  
Respiratory Chain Complexes ◽  
Gene Encoding ◽  
Chain Complexes ◽  
Ultrastructure And Function ◽  
And Function

Abstractα-Mannosidosis is a lysosomal storage disorder caused by α-mannosidase deficiency. Clinical course of the disease ranges from severe infantile to milder juvenile type and includes mental retardation, skeletal deformities, coarse facies, hepatomegaly and hearing loss. The aim of the study was to analyse mitochondrial ultrastructure and function in cultivated fibroblasts from three patients with α-mannosidosis. All patients were homozygous for the c.2248C>T mutation in the MAN2B1 gene encoding lysosomal α-mannosidase. The mutation results in incorrect protein folding and severe decrease of α-mannosidase activity. The misfolded protein is retained by the control system of endoplasmic reticulum (ER). In analysed fibroblasts, we observed dilated ER, higher amount of aberrant mitochondria and reduced mitochondrial mass compared to controls. Respiratory chain complex IV, cytochrome c oxidase (COX), activity and the ratio between COX and citrate synthase (control enzyme) were significantly increased in comparison to controls (P < 0.05). Furthermore, the activity at least from one of other respiratory chain complexes was increased in each studied cell line. Mitochondrial membrane potential as well as reactive oxygen species production were comparable with controls. Based on our results, we hypothesize more profound effect of swelled and damaged mitochondria and ER dilatation on tissues with higher energy demand than fibroblasts have.

scholarly journals 4- hydroxy-3,5-di-tret-butyl cinnamic acid restores the activity of the hippocampal mitochondria in rats under permanent focal cerebral ischemia

2021 ◽  
Author(s):  
Dmitry Pozdnyakov
Keyword(s):  
Oxidative Stress ◽  
Cerebral Ischemia ◽  
Middle Cerebral Artery ◽  
Respiratory Chain ◽  
Cinnamic Acid ◽  
Mitochondrial Function ◽  
Citrate Synthase ◽  
Mitochondrial Respiratory Chain ◽  
Respiratory Chain Complexes ◽  
Chain Complexes

Background and Purpose: Ischemic stroke remains one of the leading causes of death in the population. In addition, mitochondrial dysfunction is an essential part of the pathogenesis of cerebral ischemia and is a promising pharmacotherapeutic target. Experimental Approach: the work was performed on male Wistar rats, which were simulated cerebral ischemia by irreversible occlusion of the middle cerebral artery. 4-hydroxy-3,5-di-tret-butyl cinnamic acid (25 mg/kg, 50 mg/kg and 100 mg/kg) was injected intraperitoneally for 3 days after ischemia (daily). On the 4th day of the experiment, the changes of rat’s cognitive functions in the Morris water maze test, cellular respiration processes, the activity of the mitochondrial respiratory chain complexes and citrate synthase activity, the intensity of oxidative stress and apoptosis reactions were assessed. Key Results: it was found that the administration of 4-hydroxy-3,5-di-tret-butyl cinnamic acid at doses of 25 mg/kg and 50 mg/kg practically equivalently promotes the restoration of aerobic metabolism reactions and the activity of the mitochondrial respiratory chain complexes, decrease of the intensity of oxidative stress reactions and apoptosis, as well as an increase in the activity of citrate synthase. As a result, the restoration of mitochondrial function in the hippocampal cells contributed to the restoration of the animal’s spatial memory. Conclusion and Implications: a study showed that 4-hydroxy-3,5-di-tret-butyl cinnamic acid at doses of 25 mg/kg and 50 mg/kg has a neuroprotective effect on hippocampal neurons under conditions of permanent occlusion of the middle cerebral artery, realized by restoration of mitochondrial function.

Relationships between the activity of respiratory-chain complexes in pre- (biopsy) or post-slaughter muscle samples and feed efficiency in random-bred Ghezel lambs

2017 ◽  
Vol 57 (8) ◽  
pp. 1674
Author(s):  
M. J. Zamiri ◽  
R. Mehrabi ◽  
G. R. Kavoosi ◽  
H. Rajaei Sharifabadi
Keyword(s):  
Respiratory Chain ◽  
Feed Intake ◽  
Enzyme Activities ◽  
Feed Efficiency ◽  
Average Daily Gain ◽  
Chain Complex ◽  
Respiratory Chain Complex ◽  
Respiratory Chain Complexes ◽  
Chain Complexes ◽  
Daily Gain

The present study was conducted to determine the relationship between the activity of mitochondrial respiratory chain complexes in pre- and post-slaughter muscle samples and residual feed intake (RFI) in Ghezel male lambs born as a result of random mating. The study was based on the hypothesis that random-bred lambs with lower feed (or higher) RFI have lower (or higher) respiratory chain-complex activity in muscle samples. Lambs (n = 30) were fed a diet consisting of 70% concentrate and 30% alfalfa hay during a 70-day period. Individual feed intake and average daily gain were recorded to calculate the RFI, feed-conversion ratio (FCR) and adjusted FCR (aFCR). On the basis of these calculations, the lambs were classified into low and high groups for RFI, with FCR and aFCR (n = 22) being one standard deviation above or below the means; this was corroborated by Student’s t-test (P &lt; 0.01). At the end of the experiment, a 10-g biopsy sample was taken from the posterior side of the left femoral biceps. After 24 h, the lambs were slaughtered, and a sample from the posterior side of the right femoral biceps was dissected for determination of mitochondrial protein and respiratory chain-complex activities (Complexes I–V). The RFI was not correlated with the metabolic bodyweight and average daily gain, but was positively correlated (r = 0.56) with the average daily feed intake (P &lt; 0.01); mean daily feed intake in the low-RFI group was 200 g less than that in the high-RFI group. The FCR and aFCR were not significantly (P &gt; 0.05) correlated with average daily feed intake (r = 0.39 and r = 0.36 respectively), but showed a negative correlation (P &lt; 0.01) with average daily gain (r = –0.73 and r = –0.76 respectively). Although very high negative correlations were recorded between the activities of all five respiratory-chain complexes and RFI in muscle samples obtained before (–0.91 to –0.97) and after (–0.92 to –0.97) slaughter, Complexes I and V showed small negative correlations (–0.40) with FCR or aFCR (P &lt; 0.05). Enzyme activities of the respiratory-chain Complexes I, III and V were not significantly different between the pre- and post-slaughter biopsy samples; however, the enzyme activities of respiratory-chain Complexes II and IV were slightly higher in post-slaughter samples (P &lt; 0.01). These results suggested that it may be possible to use the enzymatic activity of respiratory-chain complexes in muscle biopsy samples for screening of lambs for RFI, providing a useful procedure for genetic selection of lambs for this component of feed efficiency. These encouraging results need to be verified in further experiments using other sheep breeds and a larger number of lambs.

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