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Redox Biology Oct 2020The mitochondrial electron transport chain utilizes a series of electron transfer reactions to generate cellular ATP through oxidative phosphorylation. A consequence of... (Review)
Review
The mitochondrial electron transport chain utilizes a series of electron transfer reactions to generate cellular ATP through oxidative phosphorylation. A consequence of electron transfer is the generation of reactive oxygen species (ROS), which contributes to both homeostatic signaling as well as oxidative stress during pathology. In this graphical review we provide an overview of oxidative phosphorylation and its inter-relationship with ROS production by the electron transport chain. We also outline traditional and novel translational methodology for assessing mitochondrial energetics in health and disease.
Topics: Electron Transport; Mitochondrial Membranes; Oxidants; Oxidative Phosphorylation; Oxidative Stress; Reactive Oxygen Species
PubMed: 32811789
DOI: 10.1016/j.redox.2020.101674 -
Nature Reviews. Endocrinology Oct 2019Despite its position as the first-line drug for treatment of type 2 diabetes mellitus, the mechanisms underlying the plasma glucose level-lowering effects of metformin... (Review)
Review
Despite its position as the first-line drug for treatment of type 2 diabetes mellitus, the mechanisms underlying the plasma glucose level-lowering effects of metformin (1,1-dimethylbiguanide) still remain incompletely understood. Metformin is thought to exert its primary antidiabetic action through the suppression of hepatic glucose production. In addition, the discovery that metformin inhibits the mitochondrial respiratory chain complex 1 has placed energy metabolism and activation of AMP-activated protein kinase (AMPK) at the centre of its proposed mechanism of action. However, the role of AMPK has been challenged and might only account for indirect changes in hepatic insulin sensitivity. Various mechanisms involving alterations in cellular energy charge, AMP-mediated inhibition of adenylate cyclase or fructose-1,6-bisphosphatase 1 and modulation of the cellular redox state through direct inhibition of mitochondrial glycerol-3-phosphate dehydrogenase have been proposed for the acute inhibition of gluconeogenesis by metformin. Emerging evidence suggests that metformin could improve obesity-induced meta-inflammation via direct and indirect effects on tissue-resident immune cells in metabolic organs (that is, adipose tissue, the gastrointestinal tract and the liver). Furthermore, the gastrointestinal tract also has a major role in metformin action through modulation of glucose-lowering hormone glucagon-like peptide 1 and the intestinal bile acid pool and alterations in gut microbiota composition.
Topics: AMP-Activated Protein Kinases; Animals; Diabetes Mellitus, Type 2; Electron Transport; Gastrointestinal Microbiome; Glucose; Humans; Hypoglycemic Agents; Metformin
PubMed: 31439934
DOI: 10.1038/s41574-019-0242-2 -
Biochimica Et Biophysica Acta.... Apr 2023
Topics: Protons; Hydrogen-Ion Concentration; Electron Transport
PubMed: 36775006
DOI: 10.1016/j.bbamem.2023.184139 -
Biochimica Et Biophysica Acta Mar 2016Cyanobacteria have evolved elaborate electron transport pathways to carry out photosynthesis and respiration, and to dissipate excess energy in order to limit cellular... (Review)
Review
Cyanobacteria have evolved elaborate electron transport pathways to carry out photosynthesis and respiration, and to dissipate excess energy in order to limit cellular damage. Our understanding of the complexity of these systems and their role in allowing cyanobacteria to cope with varying environmental conditions is rapidly improving, but many questions remain. We summarize current knowledge of cyanobacterial electron transport pathways, including the possible roles of alternative pathways in photoprotection. We describe extracellular electron transport, which is as yet poorly understood. Biological photovoltaic devices, which measure electron output from cells, and which have been proposed as possible means of renewable energy generation, may be valuable tools in understanding cyanobacterial electron transfer pathways, and enhanced understanding of electron transfer may allow improvements in the efficiency of power output. This article is part of a Special Issue entitled Organization and dynamics of bioenergetic systems in bacteria, edited by Conrad Mullineaux.
Topics: Bacterial Proteins; Cyanobacteria; Electron Transport; Electron Transport Complex I; Photosynthesis; Photosynthetic Reaction Center Complex Proteins
PubMed: 26498190
DOI: 10.1016/j.bbabio.2015.10.007 -
Molecules (Basel, Switzerland) May 2023Large-scale production of green and pollution-free materials is crucial for deploying sustainable clean energy. Currently, the fabrication of traditional energy... (Review)
Review
Large-scale production of green and pollution-free materials is crucial for deploying sustainable clean energy. Currently, the fabrication of traditional energy materials involves complex technological conditions and high costs, which significantly limits their broad application in the industry. Microorganisms involved in energy production have the advantages of inexpensive production and safe process and can minimize the problem of chemical reagents in environmental pollution. This paper reviews the mechanisms of electron transport, redox, metabolism, structure, and composition of electroactive microorganisms in synthesizing energy materials. It then discusses and summarizes the applications of microbial energy materials in electrocatalytic systems, sensors, and power generation devices. Lastly, the research progress and existing challenges for electroactive microorganisms in the energy and environment sectors described herein provide a theoretical basis for exploring the future application of electroactive microorganisms in energy materials.
Topics: Electron Transport; Technology; Physical Phenomena
PubMed: 37298848
DOI: 10.3390/molecules28114372 -
Frontiers in Bioscience (Landmark... Jan 2015The plasticity model of the electron transport chain has slowly begun to replace both the liquid model of free complexes and the solid model of supercomplexes. The... (Review)
Review
The plasticity model of the electron transport chain has slowly begun to replace both the liquid model of free complexes and the solid model of supercomplexes. The plasticity model predicts that respiratory complexes exist and function both as single complexes and as supercomplexes. The advantages of this system is an electron transport train which is able to adapt to changes in its environment. This review will investigate the current body of work on supercomplexes including their assembly, regulation, and plasticity, and particularly their role in the generation of reactive oxygen species and aging.
Topics: Aging; Animals; Electron Transport; Humans; Reactive Oxygen Species
PubMed: 25553469
DOI: 10.2741/4327 -
American Journal of Physiology. Cell... Jul 2022Reactive oxygen species (ROS) are recognized both as damaging molecules and intracellular signaling entities. In addition to its role in ATP generation, the... (Review)
Review
Reactive oxygen species (ROS) are recognized both as damaging molecules and intracellular signaling entities. In addition to its role in ATP generation, the mitochondrial electron transport chain (ETC) constitutes a relevant source of mitochondrial ROS, in particular during pathological conditions. Mitochondrial ROS homeostasis depends on species- and site-dependent ROS production, their bioreactivity, diffusion, and scavenging. However, our quantitative understanding of mitochondrial ROS homeostasis has thus far been hampered by technical limitations, including a lack of truly site- and/or ROS-specific reporter molecules. In this context, the use of computational models is of great value to complement and interpret empirical data, as well as to predict variables that are difficult to assess experimentally. During the past decades, various mechanistic models of ETC-mediated ROS production have been developed. Although these often-complex models have generated novel insights, their parameterization, analysis, and integration with other computational models are not straightforward. In contrast, phenomenological (sometimes termed "minimal") models use a relatively small set of equations to describe empirical relationship(s) between ROS-related and other parameters and generally aim to explore system behavior and generate hypotheses for experimental validation. In this review, we first discuss ETC-linked ROS homeostasis and introduce various detailed mechanistic models. Next, we present how bioenergetic parameters (e.g., NADH/NAD ratio and mitochondrial membrane potential) relate to site-specific ROS production within the ETC and how these relationships can be used to design minimal models of ROS homeostasis. Finally, we illustrate how minimal models have been applied to explore pathophysiological aspects of ROS.
Topics: Electron Transport; Electron Transport Complex I; Membrane Potential, Mitochondrial; Mitochondria; Reactive Oxygen Species
PubMed: 35613354
DOI: 10.1152/ajpcell.00455.2021 -
Annual Review of Analytical Chemistry... Jun 2023Label-free electrochemical biosensing leverages the advantages of label-free techniques, low cost, and fewer user steps, with the sensitivity and portability of... (Review)
Review
Label-free electrochemical biosensing leverages the advantages of label-free techniques, low cost, and fewer user steps, with the sensitivity and portability of electrochemical analysis. In this review, we identify four label-free electrochemical biosensing mechanisms: () blocking the electrode surface, () allowing greater access to the electrode surface, () changing the intercalation or electrostatic affinity of a redox probe to a biorecognition unit, and () modulating ion or electron transport properties due to conformational and surface charge changes. Each mechanism is described, recent advancements are summarized, and relative advantages and disadvantages of the techniques are discussed. Furthermore, two avenues for gaining further diagnostic information from label-free electrochemical biosensors, through multiplex analysis and incorporating machine learning, are examined.
Topics: Electrochemical Techniques; Electrodes; Electron Transport; Machine Learning; Diagnosis
PubMed: 36854209
DOI: 10.1146/annurev-anchem-091622-085754 -
Biochimica Et Biophysica Acta May 2016
Topics: Animals; Electron Transport; Electron Transport Chain Complex Proteins; Energy Metabolism; Gene Regulatory Networks; Humans; Protein Engineering
PubMed: 26940515
DOI: 10.1016/j.bbabio.2016.02.017 -
Biochimica Et Biophysica Acta Mar 2011The photosynthetic electron transport chain consists of photosystem II, the cytochrome b(6)f complex, photosystem I, and the free electron carriers plastoquinone and... (Review)
Review
The photosynthetic electron transport chain consists of photosystem II, the cytochrome b(6)f complex, photosystem I, and the free electron carriers plastoquinone and plastocyanin. Light-driven charge separation events occur at the level of photosystem II and photosystem I, which are associated at one end of the chain with the oxidation of water followed by electron flow along the electron transport chain and concomitant pumping of protons into the thylakoid lumen, which is used by the ATP synthase to generate ATP. At the other end of the chain reducing power is generated, which together with ATP is used for CO(2) assimilation. A remarkable feature of the photosynthetic apparatus is its ability to adapt to changes in environmental conditions by sensing light quality and quantity, CO(2) levels, temperature, and nutrient availability. These acclimation responses involve a complex signaling network in the chloroplasts comprising the thylakoid protein kinases Stt7/STN7 and Stl1/STN7 and the phosphatase PPH1/TAP38, which play important roles in state transitions and in the regulation of electron flow as well as in thylakoid membrane folding. The activity of some of these enzymes is closely connected to the redox state of the plastoquinone pool, and they appear to be involved both in short-term and long-term acclimation. This article is part of a Special Issue entitled "Regulation of Electron Transport in Chloroplasts".
Topics: Electron Transport; Oxidation-Reduction; Photosynthesis; Signal Transduction
PubMed: 21118674
DOI: 10.1016/j.bbabio.2010.11.010