scholarly journals Lichen fungi do not depend on the alga for ATP production

2021 ◽  
Author(s):  
Gulnara Tagirdzhanova ◽  
John McCutcheon ◽  
Toby Spribille
Keyword(s):  
Oxidative Phosphorylation ◽  
Atp Synthase ◽  
Mitochondrial Genomes ◽  
Symbiotic Association ◽  
Mitochondrial Oxidative Phosphorylation ◽  
Gene Encoding ◽  
Apparent Lack ◽  
Atp Production

Lichen fungi live in a symbiotic association with unicellular phototrophs and have no known aposymbiotic stage. A recent study postulated that some of them have lost mitochondrial oxidative phosphorylation and rely on their algal partners for ATP. This claim originated from an apparent lack of ATP9, a gene encoding one subunit of ATP synthase, from a few mitochondrial genomes. Here we show that while these fungi indeed have lost the mitochondrial ATP9, each retain a nuclear copy of this gene. Our analysis reaffirms that lichen fungi produce their own ATP.

scholarly journals Molecular and Supramolecular Structure of the Mitochondrial Oxidative Phosphorylation System: Implications for Pathology

Life ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 242
Author(s):  
Salvatore Nesci ◽  
Fabiana Trombetti ◽  
Alessandra Pagliarani ◽  
Vittoria Ventrella ◽  
Cristina Algieri ◽  
...  
Keyword(s):  
Oxidative Phosphorylation ◽  
Atp Synthase ◽  
Mitochondrial Permeability Transition ◽  
Ros Generation ◽  
Protonmotive Force ◽  
Mitochondrial Oxidative Phosphorylation ◽  
F1fo Atp Synthase ◽  
Functional Changes ◽  
Age Related ◽  
Mitochondrial Functions

Under aerobic conditions, mitochondrial oxidative phosphorylation (OXPHOS) converts the energy released by nutrient oxidation into ATP, the currency of living organisms. The whole biochemical machinery is hosted by the inner mitochondrial membrane (mtIM) where the protonmotive force built by respiratory complexes, dynamically assembled as super-complexes, allows the F1FO-ATP synthase to make ATP from ADP + Pi. Recently mitochondria emerged not only as cell powerhouses, but also as signaling hubs by way of reactive oxygen species (ROS) production. However, when ROS removal systems and/or OXPHOS constituents are defective, the physiological ROS generation can cause ROS imbalance and oxidative stress, which in turn damages cell components. Moreover, the morphology of mitochondria rules cell fate and the formation of the mitochondrial permeability transition pore in the mtIM, which, most likely with the F1FO-ATP synthase contribution, permeabilizes mitochondria and leads to cell death. As the multiple mitochondrial functions are mutually interconnected, changes in protein composition by mutations or in supercomplex assembly and/or in membrane structures often generate a dysfunctional cascade and lead to life-incompatible diseases or severe syndromes. The known structural/functional changes in mitochondrial proteins and structures, which impact mitochondrial bioenergetics because of an impaired or defective energy transduction system, here reviewed, constitute the main biochemical damage in a variety of genetic and age-related diseases.

Dual Mutations Reveal Interactions Between Components of Oxidative Phosphorylation in Kluyveromyces lactis

Genetics ◽  
2001 ◽  
Vol 159 (3) ◽  
pp. 929-938
Author(s):  
G D Clark-Walker ◽  
X J Chen
Keyword(s):  
Electron Transport ◽  
Oxidative Phosphorylation ◽  
Atp Synthase ◽  
Kluyveromyces Lactis ◽  
Mitochondrial Protein ◽  
Proton Pumping ◽  
Nuclear Genes ◽  
Suppressor Activity ◽  
Inner Membrane ◽  
Atp Production

Abstract Loss of mtDNA or mitochondrial protein synthesis cannot be tolerated by wild-type Kluyveromyces lactis. The mitochondrial function responsible for ρ0-lethality has been identified by disruption of nuclear genes encoding electron transport and F0-ATP synthase components of oxidative phosphorylation. Sporulation of diploid strains heterozygous for disruptions in genes for the two components of oxidative phosphorylation results in the formation of nonviable spores inferred to contain both disruptions. Lethality of spores is thought to result from absence of a transmembrane potential, ΔΨ, across the mitochondrial inner membrane due to lack of proton pumping by the electron transport chain or reversal of F1F0-ATP synthase. Synergistic lethality, caused by disruption of nuclear genes, or ρ0-lethality can be suppressed by the atp2.1 mutation in the β-subunit of F1-ATPase. Suppression is viewed as occurring by an increased hydrolysis of ATP by mutant F1, allowing sufficient electrogenic exchange by the translocase of ADP in the matrix for ATP in the cytosol to maintain ΔΨ. In addition, lethality of haploid strains with a disruption of AAC encoding the ADP/ATP translocase can be suppressed by atp2.1. In this case suppression is considered to occur by mutant F1 acting in the forward direction to partially uncouple ATP production, thereby stimulating respiration and relieving detrimental hyperpolarization of the inner membrane. Participation of the ADP/ATP translocase in suppression of ρ0-lethality is supported by the observation that disruption of AAC abolishes suppressor activity of atp2.1.

P6277The impact of exercise training in combination with statin use on skeletal muscle mitochondrial oxidative phosphorylation and metabolomics in obese rats

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
I Urbaneck ◽  
F Lorenz ◽  
I Materzok ◽  
L Maletzki ◽  
M Pietzner ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Cytochrome C ◽  
Exercise Training ◽  
Oxidative Phosphorylation ◽  
Atp Synthase ◽  
Statin Treatment ◽  
Mitochondrial Oxidative Phosphorylation ◽  
Complex Iv ◽  
Obese Rats ◽  
Statin Use

Abstract Background Exercise training (ET) and statin treatment both alter skeletal muscle function. Purpose We investigated the effects of a combined exercise and statin use on skeletal muscle mitochondrial oxidative phosphorylation (OxPhos) and metabolic alterations in obese rats. Methods Eight-week-old male Wistar rats were used. A total of 14 animals received standard chow, while 46 rats were fed a high-fat diet (HFD) for 20 weeks. After 8 weeks, the rats were randomized into 6 groups: sedentary (n=8), ET (n=6), sedentary with HFD (n=11), ET with HFD (n=11), statin with HFD (n=13) and ET with HFD and statins (n=11). Simvastatin (10mg/d/kg) was added to the drinking water. ET was performed for 12 weeks, 5 days/week for 1 h/day at 18 m/min in a motorized running wheel. OxPhos was assessed by complex-specific antibodies and targeted metabolomics using the Biocrates p180 kit. All experiments were done on frozen samples of the M. gastrocnemicus. An ANOVA with fixed effects for diet, exercise, statin treatment and statin-exercise interaction was used to identify significantly different metabolites. Results Statin use was associated with significantly lower cholesterol levels, but did not affect exercise duration and intensity compared to none-use. In sedentary animals, HFD increased OxPhos complex II (succinate dehydrogenase), complex IV (cytochrome-c-oxidase) and V (ATP synthase) while statin treatment diminished this increase in all complexes. HFD increased complex IV independent of statin treatment but had no effect on complex II and V in ET rats. Complex IV was increased due to ET only in HFD fed rats compared to rats on normal chow but decreased in contrast to sedentary animals on a HFD. With regards to metabolomics, we found 57 metabolites which were influenced by HFD while no metabolites were identified with a significant effect for ET. A significant statin-exercise interaction was found for three lysophosphatidylcholines (lysoPC a C26.0, lysoPC a C26.1, lysoPC a C24.0), one phosphatidylcholine (PC aa C42.6) and one sphingomyelin (SM C16.1). HFD decreased the concentration of all mentioned metabolites compared to standard chow fed animals. Likewise, ET increased the concentration of metabolites compared to sedentary animals on HFD. Statin treatment led to an increase, while statin in combination with ET did not rescue this effect. Conclusion HFD induced severely impaired skeletal muscle OxPhos independent of ET and statin treatment. Our findings suggest a limiting rate of NADH production in the tricarboxylic acid cycle as a potential mechanism. However, ET prevented the increase in cytochrome-c-oxidation while statins blocked the HFD induced increase in ATP synthase. Our metabolomics results imply that future research should consider the lipotoxic effects of a HFD when assessing skeletal muscle alterations due to ET or statins. Of particular interest could be the 5 metabolites that have been shown to be impacted by a statin-exercise interaction.

scholarly journals Evidence of Oxidative Phosphorylation in Zebrafish Photoreceptor Outer Segments at Different Larval Stages

2018 ◽  
Vol 66 (7) ◽  
pp. 497-509 ◽  
Author(s):  
Daniela Calzia ◽  
Greta Garbarino ◽  
Federico Caicci ◽  
Mario Pestarino ◽  
Lucia Manni ◽  
...  
Keyword(s):  
Oxidative Phosphorylation ◽  
Atp Synthase ◽  
Aerobic Metabolism ◽  
Respiratory Chain Complexes ◽  
Atp Production ◽  
Photoreceptor Outer Segments ◽  
Larval Stages ◽  
Outer Segments ◽  
Chain Complexes ◽  
Transmission Electron

Summary Previous studies on purified bovine rod outer segments (OS) disks pointed to Oxidative Phosphorylation (OXPHOS) as being the most likely mechanism involved in ATP production, as yet not fully understood, to support the first phototransduction steps. Bovine and murine rod OS disks, devoid of mitochondria, would house respiratory chain complexes I to IV and ATP synthase, similar to mitochondria. Zebrafish ( Danio rerio) is a well-suited animal model to study vertebrate embryogenesis as well as the retina, morphologically and functionally similar to its human counterpart. The present article reports fluorescence and Transmission Electron Microscopy colocalization analyses of respiratory complexes I and IV and ATP synthase with zpr3, the rod OS marker, in adult and larval zebrafish retinas. MitoTracker Deep Red 633 staining and assays of complexes I and III–IV activity suggest that those proteins are active in OS. Results show that an extramitochondrial aerobic metabolism is active in the zebrafish OS at 4 and 10 days of larval development, as well as in adults, suggesting that it is probably maintained during embryogenesis. Data support the hypothesis of an extramitochondrial aerobic metabolism in the OS of zebrafish.

scholarly journals Oxidative phosphorylation is required for powering motility and development of the sleeping sickness parasite Trypanosoma brucei within the tsetse fly vector

2021 ◽  
Author(s):  
Caroline E Dewar ◽  
Aitor Casas-Sánchez ◽  
Constentin Dieme ◽  
Aline Crouzols ◽  
Lee Haines ◽  
...  
Keyword(s):  
Oxidative Phosphorylation ◽  
Trypanosoma Brucei ◽  
Atp Synthase ◽  
Sleeping Sickness ◽  
Tsetse Fly ◽  
Tsetse Flies ◽  
Respiratory Chain Complexes ◽  
Atp Production

The single-celled parasite Trypanosoma brucei causes sleeping sickness in humans and nagana in livestock and is transmitted by hematophagous tsetse flies. Lifecycle progression from mammalian bloodstream form to tsetse midgut form and, subsequently, infective salivary gland form depends on complex developmental steps and migration within different fly tissues. As the parasite colonises the glucose-poor insect midgut, its ATP production is thought to depend on activation of mitochondrial amino acid catabolism via oxidative phosphorylation. This process involves respiratory chain complexes and the F1FO-ATP synthase, and it requires protein subunits of these complexes that are encoded in the parasite's mitochondrial DNA (kinetoplast or kDNA). Here we show that a progressive loss of kDNA-encoded functions correlates with an increasingly impaired ability of T. brucei to initiate and complete its development in the tsetse. First, parasites with a mutated F1FO-ATP synthase with a reduced capacity for oxidative phosphorylation can initiate differentiation from bloodstream to insect form, but they are unable to proliferate in vitro. Unexpectedly, these cells can still colonise the tsetse midgut. However, these parasites exhibit a motility defect and are severely impaired in colonising or migrating to subsequent tsetse tissues. Second, parasites with a fully disrupted F1FO-ATP synthase complex that is completely unable to produce ATP by oxidative phosphorylation can still differentiate to the first insect stage in vitro but die within a few days and cannot establish a midgut infection in vivo. Third, mutant parasites lacking kDNA entirely can initiate differentiation but die within 24 h. Together, these three scenarios show that efficient ATP production via oxidative phosphorylation is not essential for initial colonisation of the tsetse vector, but it is required to power trypanosome migration within the fly.

scholarly journals A drastic shift in the energetic landscape of toothed whale sperm cells

2021 ◽  
Author(s):  
L. Q. Alves ◽  
R. Ruivo ◽  
R. Valente ◽  
M. M. Fonseca ◽  
A. M. Machado ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Oxidative Phosphorylation ◽  
Sperm Motility ◽  
Sperm Cells ◽  
Mitochondrial Oxidative Phosphorylation ◽  
Endogenous Fatty Acid ◽  
Atp Production ◽  
Spermatozoa Motility ◽  
Toothed Whale

AbstractMammalia spermatozoa are a notable example of energetic compartmentalization. While mitochondrial oxidative phosphorylation is restricted to the midpiece, sperm-specific glycolysis operates in the flagellum. Consequently, these highly specialized cells exhibit a clear adaptability to fuel substrates. This plasticity is essential to ensure sperm motility, and is known to vary among species. Here we describe an extreme example of spermatozoa-energetics adaptation. We show that toothed whales exhibit impaired sperm glycolysis, due to gene and exon erosion, and demonstrate that dolphin spermatozoa motility depends uniquely on endogenous fatty acid β-oxidation, but not carbohydrates. Our findings substantiate the observation of large mitochondria in spermatozoa, possibly boosting ATP production from endogenous fatty acids. This unique energetic rewiring emphasizes the physiological body reorganisation imposed by the carbohydrate-depleted marine environment.

scholarly journals Stimulation of Alpha1-Adrenergic Receptor Ameliorates Cellular Functions of Multiorgans beyond Vasomotion through PPARδ

PPAR Research ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-21
Author(s):  
Yong-Jik Lee ◽  
Hyun Soo Kim ◽  
Hong Seog Seo ◽  
Jin Oh Na ◽  
You-Na Jang ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Oxidative Phosphorylation ◽  
Adrenergic Receptors ◽  
Adrenergic Receptor ◽  
Biological Effects ◽  
Mitochondrial Oxidative Phosphorylation ◽  
Spontaneously Hypertensive ◽  
Atp Production ◽  
Multiple Organs ◽  
Organ Specific

Cells can shift their metabolism between glycolysis and oxidative phosphorylation to enact their cell fate program in response to external signals. Widely distributed α1-adrenergic receptors (ARs) are physiologically stimulated during exercise, were reported to associate with the activating energetic AMPK pathway, and are expected to have biological effects beyond their hemodynamic effects. To investigate the effects and mechanism of AR stimulation on the physiology of the whole body, various in vitro and in vivo experiments were conducted using the AR agonist midodrine, 2-amino-N-[2-(2,5-dimethoxyphenyl)-2-hydroxy-ethyl]-acetamide. The expression of various biomarkers involved in ATP production was estimated through Western blotting, reverse transcription polymerase chain reaction, oxygen consumption rate, enzyme-linked immunosorbent assay (ELISA), fluorescence staining, and Oil red O staining in several cell lines (skeletal muscle, cardiac muscle, liver, macrophage, vascular endothelial, and adipose cells). In spontaneously hypertensive rats, blood pressure, blood analysis, organ-specific biomarkers, and general biomolecules related to ATP production were measured with Western blot analysis, immunohistochemistry, ELISA, and echocardiography. Pharmacological activation of α1-adrenergic receptors in C2C12 skeletal muscle cells promoted mitochondrial oxidative phosphorylation and ATP production by increasing the expression of catabolic molecules, including PPARδ, AMPK, and PGC-1α, through cytosolic calcium signaling and increased GLUT4 expression, as seen in exercise. It also activated those energetic molecules and mitochondrial oxidative phosphorylation with cardiomyocytes, endothelial cells, adipocytes, macrophages, and hepatic cells and affected their relevant cell-specific biological functions. All of those effects occurred around 3 h (and peaked 6 h) after midodrine treatment. In spontaneously hypertensive rats, α1-adrenergic receptor stimulation affected mitochondrial oxidative phosphorylation and ATP production by activating PPARδ, AMPK, and PGC-1α and the relevant biologic functions of multiple organs, suggesting organ crosstalk. The treatment lowered blood pressure, fat and body weight, cholesterol levels, and inflammatory activity; increased ATP content and insulin sensitivity in skeletal muscles; and increased cardiac contractile function without exercise training. These results suggest that the activation of α1-adrenergic receptor stimulates energetic reprogramming via PPARδ that increases mitochondrial oxidative phosphorylation and has healthy and organ-specific biological effects in multiple organs, including skeletal muscle, beyond its vasomotion effect. In addition, the action mechanism of α1-adrenergic receptor may be mainly exerted via PPARδ.

Myoglobin function and energy metabolism of isolated cardiac myocytes: effect of sodium nitrite

1991 ◽  
Vol 261 (1) ◽  
pp. H53-H62 ◽  
Author(s):  
J. E. Doeller ◽  
B. A. Wittenberg
Keyword(s):  
Carbon Monoxide ◽  
Oxidative Phosphorylation ◽  
Cardiac Myocytes ◽  
Sodium Nitrite ◽  
Oxygen Diffusion ◽  
Mitochondrial Membrane ◽  
Creatine Phosphokinase ◽  
Mitochondrial Oxidative Phosphorylation ◽  
Atp Production ◽  
Isolated Cardiac Myocytes

Inactivation of intracellular myoglobin by sodium nitrite or by carbon monoxide in isolated cardiac myocytes diminishes steady-state respiratory rate and phosphocreatine concentration (PCr) by approximately 25% at nonlimiting oxygen pressures; oxidative phosphorylation and glycolysis together are insufficient to maintain ATP, and PCr falls. At concentrations required to convert myoglobin to high-spin ferric myoglobin, nitrite does not affect the respiration of isolated aerobic heart mitochondria. The creatine phosphokinase-catalyzed equilibrium between PCr and ATP is not affected by nitrite. Myoglobin inactivation reduces PCr in cells in which glycolytic ATP production is blocked by iodoacetate. However, inhibition of electron transport by rotenone does block myoglobin-mediated oxygen uptake. These data suggest that functional myoglobin augments mitochondrial oxidative phosphorylation [myoglobin-mediated oxidative phosphorylation (30)]. Myoglobin itself does not cross mitochondrial membrane(s). At high oxygen pressures used here, myoglobin is everywhere saturated with oxygen, and facilitated oxygen diffusion vanishes. Oxidative phosphorylation must be augmented by some effector, such as NADH or a carrier of reducing or oxidizing equivalents that can transduce the effect of oxymyoglobin across the mitochondrial membrane(s).

Substrate regulation of mitochondrial oxidative phosphorylation in hypercapnic rabbit muscle

1992 ◽  
Vol 72 (2) ◽  
pp. 521-528 ◽  
Author(s):  
S. Nioka ◽  
Z. Argov ◽  
G. P. Dobson ◽  
R. E. Forster ◽  
H. V. Subramanian ◽  
...  
Keyword(s):  
Oxidative Phosphorylation ◽  
Intracellular Ph ◽  
Isometric Tension ◽  
Muscle Performance ◽  
Oxidative Enzymes ◽  
Rabbit Muscle ◽  
Mitochondrial Oxidative Phosphorylation ◽  
Atp Production

Endurance muscle performance is highly dependent on ATP production from mitochondrial oxidative phosphorylation. To study the role of the mitochondrial oxidative enzymes in muscle fatigue, we analyzed the relationship between the concentrations of substrates associated with ATP synthesis and the muscle performance of electrically stimulated rabbit muscle under CO2-induced acidosis. Two different conditions of pacing-induced muscle performance were produced in the gastrocnemius and soleus muscle groups in anesthetized rabbits by stimulating the sciatic nerve submaximally at two frequencies. Phosphorus nuclear magnetic resonance was used to measure ATP, phosphocreatine, and Pi and to provide data for a calculation of intracellular pH and free ADP. To induce acidosis, the animal was ventilated with 20% CO2. The administration of CO2 effectively reduced the intracellular pH from 6.9 to 6.7 and reduced the isometric tension-time integral (TTI) to below half the value measured in normocapnia at the low pacing frequency. A twofold increase in the pacing frequency resulted in a doubling of the TTI in normocapnia and a tripling of TTI in hypercapnia. The increases in TTI corresponded with increases in free ADP and Pi concentrations. Under the various conditions, all free ADP values were near the in vitro Michaelis-Menten constant (Km) of ADP. The Michaelis-Menten relationship of the oxidative phosphorylative enzymes was applied to the change in substrate concentrations with respect to TTI. From this relationship we observed that the in vivo Km of free ADP was 26 microM, which is close to the in nitro Km, and that Km and maximal reaction velocity did not change under hypercapnia and increased pacing frequency.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals HDAC6 regulates mitochondrial oxidative phosphorylation by ATP synthase beta subunit acetylation in diabetic cardiomyopathy

2012 ◽  
Vol 26 (S1) ◽  
Author(s):  
Rajaganapathi Jagannathan ◽  
Walter A Baseler ◽  
Dharendra Thapa ◽  
Tara L Croston ◽  
Danielle L Shepherd ◽  
...  
Keyword(s):  
Oxidative Phosphorylation ◽  
Atp Synthase ◽  
Diabetic Cardiomyopathy ◽  
Beta Subunit ◽  
Mitochondrial Oxidative Phosphorylation
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