The significance of hydrogenase activity for the energy metabolism of green algae: anaerobiosis favours ATP synthesis in cells of Chlorella with active hydrogenase

1986 ◽  
Vol 144 (1) ◽  
pp. 91-95 ◽  
Author(s):  
B. Mahro ◽  
Annette C. K�sel ◽  
L. H. Grimme
Keyword(s):  
Energy Metabolism ◽  
Green Algae ◽  
Atp Synthesis ◽  
Hydrogenase Activity ◽  
In Cells

scholarly journals Mitochondrial P2X7 receptor localization modulates energy metabolism enhancing physical performance

Function ◽  
2021 ◽  
Author(s):  
Alba Clara Sarti ◽  
Valentina Vultaggio-Poma ◽  
Simonetta Falzoni ◽  
Sonia Missiroli ◽  
Anna Lisa Giuliani ◽  
...  
Keyword(s):  
Energy Metabolism ◽  
Physical Fitness ◽  
P2x7 Receptor ◽  
Human Fibroblasts ◽  
Atp Synthesis ◽  
Heart Tissue ◽  
Mitochondrial Potential ◽  
Mitochondrial Energy Metabolism ◽  
Microglia Cell ◽  
Basal Expression

Abstract Basal expression of the P2X7 receptor (P2X7R) improves mitochondrial metabolism, ATP synthesis and overall fitness of immune and non-immune cells. We investigated P2X7R contribution to energy metabolism and subcellular localization in fibroblasts (mouse embryo fibroblasts and HEK293 human fibroblasts), mouse microglia (primary brain microglia and the N13 microglia cell line), and heart tissue. The P2X7R localizes to mitochondria, and its lack a) decreases basal respiratory rate, ATP-coupled respiration, maximal uncoupled respiration, resting mitochondrial potential, mitochondrial matrix Ca2+ level, b) modifies expression pattern of oxidative phosphorylation (OxPhos) enzymes, and c) severely affects cardiac performance. Hearts from P2rx7-deleted versus WT mice are larger, heart mitochondria smaller, and stroke volume (SV), ejection fraction (EF), fractional shortening (FS) and cardiac output (CO), are significantly decreased. Accordingly, physical fitness of P2X7R-null mice is severely reduced. Thus, the P2X7R is a key modulator of mitochondrial energy metabolism and a determinant of physical fitness.

ConA induced changes in energy metabolism of rat thymocytes

1992 ◽  
Vol 12 (5) ◽  
pp. 381-386 ◽  
Author(s):  
F. Buttgereit ◽  
M. D. Brand ◽  
M. Müller
Keyword(s):  
Protein Synthesis ◽  
Oxygen Consumption ◽  
Energy Metabolism ◽  
Dna Synthesis ◽  
Atp Synthesis ◽  
Proton Leak ◽  
Ehrlich Ascites ◽  
Activated State ◽  
Ehrlich Ascites Tumour ◽  
Induced Changes

The influence of ConA on the energy metabolism of quiescent rat thymocytes was investigated by measuring the effects of inhibitors of protein synthesis, proteolysis, RNA/DNA synthesis, Na+K+-ATPase, Ca2+-ATPase and mitochondrial ATP synthesis on respiration. Only about 50% of the coupled oxygen consumption of quiescent thymocytes could be assigned to specific processes using two different media. Under these conditions the oxygen is mainly used to drive mitochondrial proton leak and to provide ATP for protein synthesis and cation transport, whereas oxygen consumption to provide ATP for RNA/DNA synthesis and ATP-dependent proteolysis was not measurable. The mitogen ConA produced a persistent increase in oxygen consumption by about 30% within seconds. After stimulation more than 80% of respiration could be assigned to specific processes. The major oxygen consuming processes of ConA-stimulated thymocytes are mitochondrial proton leak, protein synthesis and Na+K+-ATPase with about 20% each of total oxygen consumption, while Ca2+-ATPase and RNA/DNA synthesis contribute about 10% each. Quiescent thymocytes resemble resting hepatocytes in that most of the oxygen consumption remains unexplained. In constrast, the pattern of energy metabolism in stimulated thymocytes is similar to that described for Ehrlich Ascites tumour cells and splenocytes, which may also be in an activated state. Most of the oxygen consumption is accounted for, so the unexplained process(es) in unstimulated cells shut(s) off on stimulation.

ConA induced changes in energy metabolism of rat thymocytes

1992 ◽  
Vol 12 (2) ◽  
pp. 109-114 ◽  
Author(s):  
F. Buttgereit ◽  
M. D. Brand ◽  
M. Müller
Keyword(s):  
Protein Synthesis ◽  
Oxygen Consumption ◽  
Energy Metabolism ◽  
Dna Synthesis ◽  
Atp Synthesis ◽  
Proton Leak ◽  
Ehrlich Ascites ◽  
Activated State ◽  
Ehrlich Ascites Tumour ◽  
Induced Changes

The influence of ConA on the energy metabolism of quiescent rat thymocytes was investigated by measuring the effects of inhibitors of protein synthesis, proteolysis, RNA/DNA synthesis, Na+K+-ATPase, Ca2+-ATPase and mitochondrial ATP synthesis on respiration. Only about 50% of the coupled oxygen consumption of quiescent thymocytes could be assigned to specific processes using two different media. Under these conditions the oxygen is mainly used to drive mitochondrial proton leak and to provide ATP for protein synthesis and cation transport, whereas oxygen consumption to provide ATP for RNA/DNA synthesis and ATP-dependent proteolysis was not measurable. The mitogen ConA produced a persistent increase in oxygen consumption by about 30% within seconds. After stimulation more than 80% of respiration could be assigned to specific processes. The major oxygen consuming processes of ConA-stimulated thymocytes are mitochondrial proton leak, protein synthesis and Na+K+-ATPase with about 20% each of total oxygen consumption, while Ca2+-ATPase and RNA/DNA synthesis contribute about 10% each. Quiescent thymocytes resemble resting hepatocytes in that most of the oxygen consumption remains unexplained. In contrast, the pattern of energy metabolism in stimulated thymocytes is similar to that described for Ehrlich Ascites tumour cells and splenocytes, which may also be in an activated state. Most of the oxygen consumption is accounted for, so the unexplained process(es) in unstimulated cells shut(s) off on stimulation.

Impaired energy metabolism as an initial step in the mechanism for 6-aminonicotinamide-induced limb malformation

Development ◽  
1980 ◽  
Vol 59 (1) ◽  
pp. 217-222
Author(s):  
Yal C. Sheffield ◽  
Robert E. Seegmiller
Keyword(s):  
Amino Acid ◽  
Energy Metabolism ◽  
Chick Embryo ◽  
Chondroitin Sulfate ◽  
Atp Synthesis ◽  
Initial Step ◽  
Chick Embryos ◽  
Impaired Energy Metabolism ◽  
All Treatment

The analogue and antagonist of nicotinamide, 6-aminonicotinamide (6-AN), impairs cartilage formation and results in shortening of the limbs when administered to chick embryos. Studies have shown that 6-AN forms an abnormal NAD analogue which inhibits the activity of NAD-dependent enzymes associated with production of ATP. To determine if an effect on ATP synthesis might be associated with the mechanism of teratogenesis in the chick embryo, ATP levels of cartilage from day-8 chick embryos treated in vitro were assayed in relation to biosynthesis of protein, DNA and chondroitin sulfate. Incorporation of 35SO4− was inhibited by 6 h of treatment with 10 µg/ml of 6-AN, whereas incorporation of [3H]thymidine and [3H]amino acid was not inhibited until 12 h. Incorporation of [3H]- glucosamine was increased at all treatment times. A decrease in the level of ATP preceded any detectable inhibition of precursor incorporation. These results are consistent with the hypothesis that 6-AN inhibits chondroitin sulfate synthesis through a reduction in the level of ATP in chondrocytes.

Reduction of nuclear encoded enzymes of mitochondrial energy metabolism in cells devoid of mitochondrial DNA

2012 ◽  
Vol 417 (3) ◽  
pp. 1052-1057 ◽  
Author(s):  
Edith E. Mueller ◽  
Johannes A. Mayr ◽  
Franz A. Zimmermann ◽  
René G. Feichtinger ◽  
Olaf Stanger ◽  
...  
Keyword(s):  
Mitochondrial Dna ◽  
Energy Metabolism ◽  
Mitochondrial Energy Metabolism ◽  
In Cells

3,5-Diiodo-l-thyronine rapidly enhances mitochondrial fatty acid oxidation rate and thermogenesis in rat skeletal muscle: AMP-activated protein kinase involvement

2009 ◽  
Vol 296 (3) ◽  
pp. E497-E502 ◽  
Author(s):  
A. Lombardi ◽  
P. de Lange ◽  
E. Silvestri ◽  
R. A. Busiello ◽  
A. Lanni ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Fatty Acids ◽  
Fatty Acid ◽  
Energy Metabolism ◽  
Fatty Acid Oxidation ◽  
Atp Synthesis ◽  
Acid Oxidation ◽  
Mitochondrial Fatty Acid Oxidation ◽  
Mitochondrial Fatty Acid ◽  
Amp Activated Protein Kinase

Triiodothyronine regulates energy metabolism and thermogenesis. Among triiodothyronine derivatives, 3,5-diiodo-l-thyronine (T2) has been shown to exert marked effects on energy metabolism by acting mainly at the mitochondrial level. Here we investigated the capacity of T2 to affect both skeletal muscle mitochondrial substrate oxidation and thermogenesis within 1 h after its injection into hypothyroid rats. Administration of T2 induced an increase in mitochondrial oxidation when palmitoyl-CoA (+104%), palmitoylcarnitine (+80%), or succinate (+30%) was used as substrate, but it had no effect when pyruvate was used. T2 was able to 1) activate the AMPK-ACC-malonyl-CoA metabolic signaling pathway known to direct lipid partitioning toward oxidation and 2) increase the importing of fatty acids into the mitochondrion. These results suggest that T2 stimulates mitochondrial fatty acid oxidation by activating several metabolic pathways, such as the fatty acid import/β-oxidation cycle/FADH2-linked respiratory pathways, where fatty acids are imported. T2 also enhanced skeletal muscle mitochondrial thermogenesis by activating pathways involved in the dissipation of the proton-motive force not associated with ATP synthesis (“proton leak”), the effect being dependent on the presence of free fatty acids inside mitochondria. We conclude that skeletal muscle is a target for T2, and we propose that, by activating processes able to enhance mitochondrial fatty acid oxidation and thermogenesis, T2 could play a role in protecting skeletal muscle against excessive intramyocellular lipid storage, possibly allowing it to avoid functional disorders.

scholarly journals A microbial eukaryote with a unique combination of purple bacteria and green algae as endosymbionts

2021 ◽  
Vol 7 (24) ◽  
pp. eabg4102
Author(s):  
Sergio A. Muñoz-Gómez ◽  
Martin Kreutz ◽  
Sebastian Hess
Keyword(s):  
Energy Metabolism ◽  
Green Algae ◽  
Purple Bacteria ◽  
Ecological Niches ◽  
Unique Combination ◽  
Anoxygenic Photosynthesis ◽  
Microbial Eukaryote ◽  
Eukaryotic Algae ◽  
Candidate Species ◽  
Partial Overlap

Oxygenic photosynthesizers (cyanobacteria and eukaryotic algae) have repeatedly become endosymbionts throughout evolution. In contrast, anoxygenic photosynthesizers (e.g., purple bacteria) are exceedingly rare as intracellular symbionts. Here, we report on the morphology, ultrastructure, lifestyle, and metagenome of the only “purple-green” eukaryote known. The ciliate Pseudoblepharisma tenue harbors green algae and hundreds of genetically reduced purple bacteria. The latter represent a new candidate species of the Chromatiaceae that lost known genes for sulfur dissimilation. The tripartite consortium is physiologically complex because of the versatile energy metabolism of each partner but appears to be ecologically specialized as it prefers hypoxic sediments. The emergent niche of this complex symbiosis is predicted to be a partial overlap of each partners’ niches and may be largely defined by anoxygenic photosynthesis and possibly phagotrophy. This purple-green ciliate thus represents an extraordinary example of how symbiosis merges disparate physiologies and allows emergent consortia to create novel ecological niches.

scholarly journals In VivoRegulation of Oxidative Phosphorylation in Cells Harboring a Stop-codon Mutation in Mitochondrial DNA-encoded CytochromecOxidase Subunit I

2001 ◽  
Vol 276 (50) ◽  
pp. 46925-46932 ◽  
Author(s):  
Marilena D'Aurelio ◽  
Francesco Pallotti ◽  
Antoni Barrientos ◽  
Carl D. Gajewski ◽  
Jennifer Q. Kwong ◽  
...  
Keyword(s):  
Mitochondrial Dna ◽  
Oxidative Phosphorylation ◽  
Mammalian Cells ◽  
Stop Codon ◽  
Atp Synthesis ◽  
Stop Codon Mutation ◽  
Oxidase Subunit ◽  
Steady State Levels ◽  
Codon Mutation ◽  
In Cells

The mechanisms that regulate oxidative phosphorylation in mammalian cells are largely unknown. To address this issue, cybrids were generated by fusing osteosarcoma cells devoid of mitochondrial DNA (mtDNA) with platelets from a patient with a stop-codon mutation in cytochromecoxidase subunit I (COX I). The molecular and biochemical characteristics of cybrids harboring varying levels of mutated mitochondrial DNA were studied. We found a direct correlation between the levels of mutated COX I DNA and mutated COX I mRNA, whereas the levels of COX I total mRNA were unchanged. COX I polypeptide synthesis and steady-state levels were inversely proportional to mutation levels. Cytochromecoxidase subunit II was reduced proportionally to COX I, indicating impairment in complex assembly. COX enzymatic activity was inversely proportional to the levels of mutated mtDNA. However, both cell respiration and ATP synthesis were preserved in cells with lower proportions of mutated genomes, with a threshold at ∼40%, and decreased linearly with increasing mutated mtDNA. These results indicate that COX levels in mutated cells were not regulated at the transcriptional, translational, and post-translational levels. Because of a small excess of COX capacity, the levels of expression of COX subunits exerted a relatively tight control on oxidative phosphorylation.

Thyroid Hormones and Mitochondria

2002 ◽  
Vol 22 (1) ◽  
pp. 17-32 ◽  
Author(s):  
Fernando Goglia ◽  
Elena Silvestri ◽  
Antonia Lanni
Keyword(s):  
Energy Metabolism ◽  
Thyroid Hormones ◽  
Uncoupling Protein ◽  
Atp Synthesis ◽  
Energy Transduction ◽  
Clear Cut ◽  
Expression Of Genes ◽  
Molecular Determinant ◽  
Mitochondrial Functions ◽  
Oxidative Processes

Because of their central role in the regulation of energy-transduction, mitochondria, the major site of oxidative processes within the cell, are considered a likely subcellular target for the action that thyroid hormones exert on energy metabolism. However, the mechanism underlying the regulation of basal metabolic rate (BMR) by thyroid hormones still remains unclear. It has been suggested that these hormones might uncouple substrate oxidation from ATP synthesis, but there are no clear-cut data to support this idea. Two iodothyronines have been identified as effectors of the actions of thyroid hormones on energy metabolism: 3',3,5-triiodo-L-thyronine (T3) and 3,5-diiodo-L-thyronine (T2). Both have significant effects on BMR, but their mechanisms of action are not identical. T3 acts on the nucleus to influence the expression of genes involved in the regulation of cellular metabolism and mitochondria function; 3,5-T2, on the other hand, acts by directly influencing the mitochondrial energy-transduction apparatus. A molecular determinant of the effects of T3 could be uncoupling protein-3 (UCP-3), while the cytochrome-c oxidase complex is a possible target for 3,5-T2. In conclusion, it is likely that iodothyronines regulate energy metabolism by both short-term and long-term mechanisms, and that they act in more than one way in affecting mitochondrial functions.

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