Cellular metabolism

2021 ◽  
pp. 105-194
Keyword(s):  
Electron Transport Chain ◽  
Inborn Errors Of Metabolism ◽  
Krebs Cycle ◽  
Cellular Metabolism ◽  
Atp Synthesis ◽  
The Body ◽  
Clinical Aspects ◽  
Inborn Errors ◽  
Transport Chain ◽  
Cellular Compartments

‘Cellular metabolism’ addresses the major biochemical pathways and processes of the cells of the body. These include the central metabolic pathways involved in energy production: the tricarboxylic acid or Krebs cycle, and ATP synthesis through the electron transport chain and oxidative phosphorylation (chemiosmotic theory). Metabolism of each of the major fuel sources is considered: lipids, carbohydrates, and proteins, including energy storage as fat and glycogen, and excretion of nitrogen via the urea cycle. The different cellular compartments for metabolism are explored, as is the integration and regulation of the metabolic processes in a number of conditions such as fasting and starvation, exercise, pregnancy, and diabetes. Finally in this chapter the clinical aspects of metabolism are discussed, including energy balance and nutrition, obesity, and inborn errors of metabolism.

scholarly journals Complex II subunit SDHD is critical for cell growth and metabolism, which can be partially restored with a synthetic ubiquinone analog

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Aloka B. Bandara ◽  
Joshua C. Drake ◽  
David A. Brown
Keyword(s):  
Mammalian Cells ◽  
Krebs Cycle ◽  
Atp Synthesis ◽  
Hek293 Cells ◽  
Knockout Mutant ◽  
Complex Ii ◽  
Growth Defects ◽  
Transport Chain ◽  
Mutant Cells

Abstract Background Succinate dehydrogenase (Complex II) plays a dual role in respiration by catalyzing the oxidation of succinate to fumarate in the mitochondrial Krebs cycle and transferring electrons from succinate to ubiquinone in the mitochondrial electron transport chain (ETC). Mutations in Complex II are associated with a number of pathologies. SDHD, one of the four subunits of Complex II, serves by anchoring the complex to the inner-membrane and transferring electrons from the complex to ubiquinone. Thus, modeling SDHD dysfunction could be a valuable tool for understanding its importance in metabolism and developing novel therapeutics, however no suitable models exist. Results Via CRISPR/Cas9, we mutated SDHD in HEK293 cells and investigated the in vitro role of SDHD in metabolism. Compared to the parent HEK293, the knockout mutant HEK293ΔSDHD produced significantly less number of cells in culture. The mutant cells predictably had suppressed Complex II-mediated mitochondrial respiration, but also Complex I-mediated respiration. SDHD mutation also adversely affected glycolytic capacity and ATP synthesis. Mutant cells were more apoptotic and susceptible to necrosis. Treatment with the mitochondrial therapeutic idebenone partially improved oxygen consumption and growth of mutant cells. Conclusions Overall, our results suggest that SDHD is vital for growth and metabolism of mammalian cells, and that respiratory and growth defects can be partially restored with treatment of a ubiquinone analog. This is the first report to use CRISPR/Cas9 approach to construct a knockout SDHD cell line and evaluate the efficacy of an established mitochondrial therapeutic candidate to improve bioenergetic capacity.

scholarly journals Reduced efficiency, but increased fat oxidation, in mitochondria from human skeletal muscle after 24-h ultraendurance exercise

2007 ◽  
Vol 102 (5) ◽  
pp. 1844-1849 ◽  
Author(s):  
Maria Fernström ◽  
Linda Bakkman ◽  
Michail Tonkonogi ◽  
Irina G. Shabalina ◽  
Zinaida Rozhdestvenskaya ◽  
...  
Keyword(s):  
Electron Transport ◽  
Electron Transport Chain ◽  
Uncoupling Protein ◽  
Mitochondrial Protein ◽  
Oxygen Demand ◽  
Atp Synthesis ◽  
Whole Body ◽  
Palmitoyl Carnitine ◽  
Transport Chain ◽  
Mitochondrial Efficiency

The hypothesis that ultraendurance exercise influences muscle mitochondrial function has been investigated. Athletes in ultraendurance performance performed running, kayaking, and cycling at 60% of their peak O2 consumption for 24 h. Muscle biopsies were taken preexercise (Pre-Ex), postexercise (Post-Ex), and after 28 h of recovery (Rec). Respiration was analyzed in isolated mitochondria during state 3 (coupled to ATP synthesis) and state 4 (noncoupled respiration), with fatty acids alone [palmitoyl carnitine (PC)] or together with pyruvate (Pyr). Electron transport chain activity was measured with NADH in permeabilized mitochondria. State 3 respiration with PC increased Post-Ex by 39 and 41% ( P < 0.05) when related to mitochondrial protein and to electron transport chain activity, respectively. State 3 respiration with Pyr was not changed ( P > 0.05). State 4 respiration with PC increased Post-Ex but was lower than Pre-Ex at Rec ( P < 0.05 vs. Pre-Ex). Mitochondrial efficiency [amount of added ADP divided by oxygen consumed during state 3 (P/O ratio)] decreased Post-Ex by 9 and 6% ( P < 0.05) with PC and PC + Pyr, respectively. P/O ratio remained reduced at Rec. Muscle uncoupling protein 3, measured with Western blotting, was not changed Post-Ex but tended to decrease at Rec ( P = 0.07 vs. Pre-Ex). In conclusion, extreme endurance exercise decreases mitochondrial efficiency. This will increase oxygen demand and may partly explain the observed elevation in whole body oxygen consumption during standardized exercise (+13%). The increased mitochondrial capacity for PC oxidation indicates plasticity in substrate oxidation at the mitochondrial level, which may be of advantage during prolonged exercise.

scholarly journals KREBER`S ADVENTURES: COMPUTER GAME ABOUT THE ATP FORMATION

2015 ◽  
Vol 13 ◽  
pp. 11
Author(s):  
F. J. Baêta ◽  
B. M. Souza ◽  
G. B. Marinhoi ◽  
J. G. Andrade ◽  
J. C. Souza ◽  
...  
Keyword(s):  
Electron Transport ◽  
Electron Transport Chain ◽  
Krebs Cycle ◽  
Computer Game ◽  
Usability Testing ◽  
Digital Games ◽  
Glycolytic Pathway ◽  
Pedagogical Practice ◽  
Atp Formation ◽  
Transport Chain

Introduction: Biochemistry, as well as other subjects related to molecular area, have several abstract and difficult concepts to be understood, therefore, many educational innovations have been developed, highlighting the digital games. The digital games feature a playful and motivational character that encourages students during the concepts learning, with a different way to learning the concepts studied. Objectives: The objective of this study was the development of a computer game focused on the concepts of ATP formation, including the glycolytic pathway, Krebs cycle and Electron Transport Chain, as well as aspects related to the regulation, and evaluate the usability of it, as well as some evidence of its educational potential. Material and methods: The development of the game followed the following steps: definition of the subject; understanding of game developer (it was chosen the GameMaker); storyboard creation of the game; prototyping, implementation and usability testing. For the evaluation, inspection usability was performed (without involving end users) and subsequently the cognitive route and the usability questionnaire (the latter two with students of the discipline of Biochemistry). Results: The game approached the energy metabolism in three phases: the glycolytic pathway, Krebs cycle and electron transport chain. Each phase has a different purpose, with some questions about the ways. To complete the game, you must correctly answer the questions, avoid the obstacles and achieve the goals of each phase. After usability testing, it found that users could, in a playful manner, actively interact with the content addressed and, through the difficulties presented in the game, had the opportunity to expand and review their knowledge. Conclusions: The game was identified as a motivating and innovative proposal for  teaching, and it had good usability for undergraduate students. The ludic worked as a pedagogical practice encourages student for learning and may assist in the construction of knowledge.

scholarly journals Complex II Subunit SDHD is Critical for Cell Growth and Metabolism, Which can be Partially Restored with A Synthetic Ubiquinone Analog

2020 ◽  
Author(s):  
Aloka B Bandara ◽  
David A Brown ◽  
Joshua Drake
Keyword(s):  
Mammalian Cells ◽  
Krebs Cycle ◽  
Atp Synthesis ◽  
Hek293 Cells ◽  
Knockout Mutant ◽  
Complex Ii ◽  
Growth Defects ◽  
Transport Chain ◽  
Mutant Cells

Abstract Background: Succinate dehydrogenase (Complex II) plays a dual role in respiration by catalyzing the oxidation of succinate to fumarate in the mitochondrial Krebs cycle and transferring electrons from succinate to ubiquinone in the mitochondrial electron transport chain (ETC). Mutations in Complex II are associated with a number of pathologies. SDHD, one of the four subunits of Complex II, serves by anchoring the complex to the inner-membrane and transferring electrons from the complex to ubiquinone. Thus, modeling SDHD dysfunction could be a valuable tool for understanding its importance in metabolism and developing novel therapeutics, however no suitable models exist. Results: Via CRISPR/Cas9, we mutated SDHD in HEK293 cells and investigated the in vitro role of SDHD in metabolism. Compared to the parent HEK293, the knockout mutant HEK293ΔSDHD produced significantly less number of cells in culture. The mutant cells predictably had suppressed Complex II-mediated mitochondrial respiration, but also Complex I-mediated respiration. SDHD mutation also adversely affected glycolytic capacity and ATP synthesis. Mutant cells were more apoptotic and susceptible to necrosis. Treatment with the mitochondrial therapeutic idebenone partially improved oxygen consumption and growth of mutant cells. Conclusions: Overall, our results suggest that SDHD is vital for growth and metabolism of mammalian cells, and that respiratory and growth defects can be partially restored with treatment of a ubiquinone analog. This is the first report to use CRISPR/Cas9 approach to construct a knockout SDHD cell line and evaluate the efficacy of an established mitochondrial therapeutic candidate to improve bioenergetic capacity.

DIAGNOSIS AND TREATMENT: SOME DISEASES, SYNDROMES, AND CONDITIONS ASSOCIATED WITH AN UNUSUAL ODOR

PEDIATRICS ◽  
1968 ◽  
Vol 41 (5) ◽  
pp. 993-995
Author(s):  
Thomas E. Cone
Keyword(s):  
Inborn Errors Of Metabolism ◽  
Acid Metabolism ◽  
Clinical Medicine ◽  
The Body ◽  
Ayurvedic Medicine ◽  
Precise Description ◽  
Inborn Errors ◽  
Diagnostic Significance ◽  
Sense Of Smell ◽  
Almost All

This Quotation from the writings of one of the founders of ancient Hindu or Ayurvedic medicine, is evidence that Suśruta was aware of the diagnostic significance of odors in many diseases. For most contemporary physicians an awareness of the importance of the sense of smell in clinical medicine was rekindled largely by the discovery of phenylketonuria by Følling ill 1934.2 He, as has almost every other student of this disease, called attention to a distinctive odor of patients with PKU. With the burgeoning of our knowledge of inborn errors of metabolism during the last decade, we are now aware of at least five additional conditions in which the patient's odor is unusual; these conditions include disorders of amino acid as well as fatty acid metabolism. ODORS IN CLINICAL MEDICINE The quality or character of odors described ill clinical medicine for the same disease varies from author to author. Although an odor may be defined as a volatile emanation that is perceived by the sense of smell, the precise description of a particular odor is extremely difficult. This may be because most of us, unlike almost all other mammals, pay little attention to the odors around us. It is not that we are anosmic but rather that our faculty for discniminating smell in clinical practice has atrophied from disuse. Sources of Patients' Odors Odors arise chiefly from the secreta and excreta of the body: sweat, sebum from the skin; secreta from the nose, mouth, throat, bronchi, and lungs; urine, stool and vaginal discharges; wound suppuration; and from necrotic tissue.

SGPL1 regulates expression of electron transport chain components to modulate cellular metabolism in the adrenal gland

2021 ◽  
Author(s):  
Jack Williams ◽  
Chris Smith ◽  
Avinaash Maharaj ◽  
Ruth Kwong ◽  
Charlotte Hall ◽  
...  
Keyword(s):  
Electron Transport ◽  
Adrenal Gland ◽  
Electron Transport Chain ◽  
Cellular Metabolism ◽  
Transport Chain
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