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Cellular and Immunobiology
Published in Karl H. Pang, Nadir I. Osman, James W.F. Catto, Christopher R. Chapple, Basic Urological Sciences, 2021
Masood Moghul, Sarah McClelland, Prabhakar Rajan
TCA (Krebs) cycle takes place within the mitochondria.As acetyl CoA is oxidised, it de-oxidises (reduces) electron carriers NAD and FAD → NADH, FADH2.NAD and FAD pass their electrons into the electron transport chain—oxidative phosphorylation.As electrons pass along the chain, they lose energy, which is used to pump hydrogen ions into inter-membrane space of mitochondria, causing an electrochemical gradient.Hydrogen flows back down the electrochemical current and through membrane enzyme ATP synthase, producing ATP.This process is called chemiosmosis and yields the most ATP from glucose.
Whole-Body Regulation of Energy Expenditure, Exercise Fuel Selection, and Dietary Recommendations
Published in Peter M. Tiidus, Rebecca E. K. MacPherson, Paul J. LeBlanc, Andrea R. Josse, The Routledge Handbook on Biochemistry of Exercise, 2020
Oxidative Phosphorylation: At rest or with exercise below the respiratory threshold (∼60%–70% V˙O2max), aerobic glycolysis predominates. Here, pyruvic acid enters the mitochondria rather than being reduced to lactic acid and is converted into acetyl-CoA by the action of the pyruvate dehydrogenase complex, making the electron carrier nicotinamide adenine dinucleotide (NADH) available, as it is not needed to form lactic acid. The acetyl-CoA enters the citric acid cycle, where additional NADH and another electron carrier (FADH2), CO2, and a small amount of ATP (substrate phosphorylation) are formed. Ultimately, these carriers pass electrons along the electron transport chain (ETC), also located within the mitochondria, resulting in ATP synthesis, utilizing O2, and forming H2O as an end product. Since the 1960s this electron carrier oxidation coupling to ATP synthesis (chemiosmotic theory; 42) has been the prevailing explanation underlying how oxidative phosphorylation works, but data are accumulating that the torsional theory may more accurately explain the detail of this key step in oxidative metabolism (2, 45). Finally, aerobic metabolism predominates at rest and with low-to-moderate exercise intensities until the rate of pyruvic acid formation from accelerated glycolysis exceeds its maximal removal rate as acetyl-CoA into the citric acid cycle, at which point anaerobic glycolysis ramps up and muscle lactic acid production increases rapidly.
Macronutrientst, Micronutrients, and Metabolism
Published in Emily Crews Splane, Neil E. Rowland, Anaya Mitra, Psychology of Eating, 2019
Emily Crews Splane, Neil E. Rowland, Anaya Mitra
The universal chemical or molecule used to drive cellular processes is adenosine triphosphate (ATP). ATP is a high energy state molecule (adenosine with three attached phosphate groups in a chain) that acts as an energy source or donor (Figure 2.1). These phosphate groups can be removed sequentially by enzymatic reaction(s) to yield lower energy forms – adenosine diphosphate and adenosine monophosphate. The phosphate groups are transferred to recipient molecules which then are transformed into an active form to execute their particular biological function. The used or dephosphorylated ATP then can be regenerated by an enzyme (ATP synthase) that is powered by a proton gradient or pump called the chemiosmotic potential which is set up in the citric acid cycle (Figure 2.2). This latter is a cycle of chemical transformations fueled by aerobic metabolism of nutrient-derived fuels. These reactions occur in mitochondria, which are specialized organelles inside each cell. Cells that are metabolically most active usually have more mitochondria than less active cells.
Evaluation of the antimicrobial mechanism of biogenic selenium nanoparticles against Pseudomonas fluorescens
Published in Biofouling, 2023
Ying Xu, Ting Zhang, Jiarui Che, Jiajia Yi, Lina Wei, Hongliang Li
ATP is an important energy molecule for all living organisms and it plays a vital role in a variety of physiological processes such as respiration, metabolism, and enzymatic reactions (Li et al. 2016). Under normal circumstances, intracellular ATP levels remain in a stable state. However, the disruption of cell homeostasis and integrity may cause changes in intracellular ATP concentrations. Compared with the control group, it was found that the intracellular ATP concentrations decreased significantly after treatment with SeNPs (p < 0.05), and the extracellular ATP concentrations showed an increasing trend, among which 2 × MIC of SeNPs led to the greatest depletion (Figure 6). This depletion of cellular ATP indicated an impaired energy metabolic pathway, which in turn might impede ATP synthesis. On the other hand, SeNPs increased the cell membrane permeability, resulting in leakage of intracellular protons, so that the inside and outside of the cell membrane formed a proton gradient difference. According to the chemiosmosis theory, this gradient difference is the electromotive potential of the proton. The leakage of the proton hindered the synthesis of ATP, leading to the reduction of the intracellular ATP content (Jung et al. 2015).
Antimicrobial susceptibility and sessile behaviour of bacteria isolated from a minimally processed vegetables plant
Published in Biofouling, 2018
Ana Meireles, Sílvia Faia, Efstathios Giaouris, Manuel Simões
The bacteria tested were isolated from a MPV plant that uses SH as a disinfectant (Meireles et al. 2017). The efficiency of this disinfectant in both killing and removal of biofilm cells of the 20 isolated bacteria was evaluated and compared to PA, an alternative disinfectant (Banach et al. 2015; Zhang et al. 2018). SH and PA are both oxidizing biocides. SH interferes with the cytoplasmic membrane integrity due to irreversible enzymatic inhibition, causes biosynthetic alterations in the cell metabolism and phospholipid degradation (Estrela et al. 2002). PA disrupts the chemiosmotic function of the lipoprotein cytoplasmic membrane and causes rupture of cell walls (Kitis 2004). SH was more efficient than PA in biofilm killing, as it promoted a complete CFU reduction of 70% of the isolates. However, this treatment was not effective against biofilms of R. caricis and R. erythropolis. PA action was unable to cause total CFU reduction of any of the isolates tested. Daddiego et al. (2018) had a distinct result and concluded that PA was more effective than SH, as PA was able to access and kill bacteria present in fresh-cut leaves. Neo et al. (2013) found that PA and SH caused similar disinfection.
A look into the use of Raman spectroscopy for brain and breast cancer diagnostics: linear and non-linear optics in cancer research as a gateway to tumor cell identity
Published in Expert Review of Molecular Diagnostics, 2020
Halina Abramczyk, Beata Brozek-Pluska, Arkadiusz Jarota, Jakub Surmacki, Anna Imiela, Monika Kopec
First, we must understand intracellular retinoid metabolism in brain cancer cells. Vitamin A plays an important role in cellular signal transduction in many vital processes. Proton gradient triggers the synthesis ATP. There are two types of generation of proton gradient: the light-activated mechanism in vision processes (rhodopsin family),the electron transport chain forms a proton gradient across the inner mitochondrial membrane, which drives the synthesis of ATP via chemiosmosis.