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Neuromuscular Physiology
Published in Michael H. Stone, Timothy J. Suchomel, W. Guy Hornsby, John P. Wagle, Aaron J. Cunanan, Strength and Conditioning in Sports, 2023
Michael H. Stone, Timothy J. Suchomel, W. Guy Hornsby, John P. Wagle, Aaron J. Cunanan
Inner membrane. The inner membrane is freely permeable only to oxygen, carbon dioxide, and water (5). About 60–70 % of the proteins in the mitochondria are found in the inner membrane, many of which are transport proteins, largely controlling the movement of various substances into and out of the matrix. The cristae extend into the matrix at different depths are the main sites of mitochondrial energy conversion. A small proton gradient between the intermembrane space (pH 7.2–7.4) and the matrix (pH 7.9–8) drives ATP production catalyzed by the ATP synthase enzymes in the membranes of the cristae.
Cardiovascular Disease and Oxidative Stress
Published in Peter Grunwald, Pharmaceutical Biocatalysis, 2019
Marco Fernandes, Alisha Patel, Holger Husi
Redox regulation is important in physiological functions. Redox regulation is involved with transcriptional and translational regulation of encoding antioxidant enzymes (Manganas et al., 2017). Regulation occurs within the cellular inner membrane of the mitochondria. Redox regulation of physiologic functions is important because increased levels of ROS are signalling molecules that can affect physiological functions (i.e. cells, tissues and organs). Redox regulation maintains the balance of ROS levels in order to keep physiological functions at a base level and to keep the control of various cellular functions to prevent diseases from appearing (Grant, 2008).
Liver, GI and Metabolism
Published in Sarah Armstrong, Barry Clifton, Lionel Davis, Primary FRCA in a Box, 2019
Sarah Armstrong, Barry Clifton, Lionel Davis
Final metabolic pathway of cellular respiration that occurs on inner mitochondrial membraneTendency for electrons to be transferred from activated carriers (e.g. NADH – ‘loaded’ during CAC) to cascade of lower potential carriers (electron transfer chain)Process involves many enzymes, including those of cytochrome oxidase systemProton pumps in inner mitochondrial membrane are activated by flow of electrons through them pumping H+ ions out and creating gradient that generates ATP (via ATP synthase) by driving H+ ions back across inner membraneRequires oxygen and results in liberation of 30 ATP molecules per molecule of glucose
Omentin-1 promotes mitochondrial biogenesis via PGC1α-AMPK pathway in chondrocytes
Published in Archives of Physiology and Biochemistry, 2023
Zhigang Li, Yao Zhang, Fengde Tian, Zihua Wang, Haiyang Song, Haojie Chen, Baolin Wu
The mitochondrion is the "powerhouse" in eukaryotic cells. Mitochondrial biogenesis is the process of increasing cellular metabolic capacity, featured with the synthesis of enzymes for both glycolysis and oxidative phosphorylation (Jornayvaz and Shulman 2010). An efficient mitochondrial biogenesis needs the import of nuclear protein as well as mitochondrial replication, mitochondrial fusion and fission (Nunnari and Suomalainen 2012). Mitochondria in mammalian cells contain more than 1500 proteins, but only 13 proteins are coded in mitochondrial DNA, a majority of them are synthesised from nuclear DNA coding genes. Various mitochondrial molecular markers are used to study the mitochondrial regulation in eukaryotes. Translocase of the outer membrane (TOM) complex is a membrane-bound translocator vital to import mitochondrial precursors, and TOM complex includes several subunits including TOM20, TOM40 and TOM70 and is secured by TOM5, TOM6, TOM7, etc. (Ahting et al.1999). Several subunits of mitochondrial ATP synthases are also used as the markers of functional mitochondria, including ATPA, ATP5C1, ATPD and other subunits. The electron transport chain (ETC) located within the mitochondrial inner membrane composes of four protein complexes. Succinate dehydrogenase complex iron-sulfur subunit B (SDHB) links the pathways of Krebs cycle and oxidative phosphorylation. Mitochondrial DNA encoded subunits (MTCO1, MTCO2, MTCO3) are important subunits of complex IV (Zhao et al.2019).
Sericin-mediated improvement of dysmorphic cardiac mitochondria from hypercholesterolaemia is associated with maintaining mitochondrial dynamics, energy production, and mitochondrial structure
Published in Pharmaceutical Biology, 2022
Kitiya Rujimongkon, Sumate Ampawong, Duangnate Isarangkul, Onrapak Reamtong, Pornanong Aramwit
High serum cholesterol is one of the factors that leads to myocardial and cardiac mitochondrial degeneration (Ampawong et al. 2017a). Ultrastructural observations of mitochondria have revealed four mitochondrial stages from a normal to a severely degenerated structure. The normal stage involves a structure containing double membranes (inner and outer membranes) covering the intermembrane space. The inner membrane forms pore-like structures termed crista junctions in the mitochondrial matrix. The swelling stage involves the first dysmorphic structure, which includes an increased size, distensions of the intercellular matrix, and partial disappearance of cristae. The spheroid stage is characterised by the complete loss of cristae and the formation of multiple cysts in the matrix. In the final stage, the ghost stage, the membrane disappears, leaving granular and electrodense material (Mariappan et al. 2007; Ampawong et al. 2017a, 2017b). Dysmorphic cardiac mitochondria under hypercholesterolemic coupled with hyperglycaemic conditions have revealed different numbers of mitochondria between the dysmorphic and normal stages (Ampawong et al. 2017a). This evidence suggests the possibility that high serum cholesterol levels are related to the structure of cardiac mitochondria, are associated with mitochondrial dysfunction and result in organ failure, especially in the heart.
Therapeutic potential of PGC-1α in age-related macular degeneration (AMD) – the involvement of mitochondrial quality control, autophagy, and antioxidant response
Published in Expert Opinion on Therapeutic Targets, 2021
Juha Hyttinen, Janusz Blasiak, Pasi Tavi, Kai Kaarniranta
Mitochondria are the primary energy-suppliers of the cell in normal physiological conditions, producing adenosine triphosphate (ATP) through several pathways. The main pathway is the oxidative phosphorylation (OXPHOS), in which electrons are transferred between the respiratory complexes I to IV in the electron transport chain. An electrochemical gradient is formed across the inner membrane and this leads to the conversion of adenosine diphosphate (ADP) to ATP by complex V. In addition, the citric acid cycle and β-oxidation produce the reduced form of nicotinamide adenine dinucleotide (NAD) and flavin adenine dinucleotide, which are essential co-factors participating in OXPHOS. Furthermore, RPE cells have a capacity to undergo ketogenesis, where fatty acids are metabolized to β-OH-butyrate as an alternative energy source [15].