China
Africa
Explore chapters and articles related to this topic
Bacteria
Published in Julius P. Kreier, Infection, Resistance, and Immunity, 2022
In obligate aerobic organisms the TEA is oxygen and the process is called aerobic respiration. This type of metabolism, where oxygen is an obligatory nutrient, is found in all animals and in aerobic bacteria. In some obligate aerobes (e.g., hydrogen oxidizing bacteria), the organism must grow by aerobic respiration but the organism is sensitive to oxygen above about 0.2 atmospheres. These bacteria, known as microaerophilic, contain an essential enzyme that is inactivated by oxygen (e.g., hy-drogenase). A variation unique to the microbial world is that some bacteria have the capacity to substitute inorganic chemicals (i.e., carbonate, nitrate, nitrite, sulfate) in place of oxygen as their TEA and grow in the absence of oxygen. This process is called anaerobic respiration. An additional variation, known as fermentation, is found in other microbes that have the capacity to transfer electrons to partially reduced organic compounds in the absence of a complete electron transport system and derive energy from the process. For example, some fermenters are unable to synthesize cytochromes which are essential components of an electron transport system.
Oxygen Transport
Published in James N. Cobley, Gareth W. Davison, Oxidative Eustress in Exercise Physiology, 2022
P.N. Chatzinikolaou, N.V. Margaritelis, A.N. Chatzinikolaou, V. Paschalis, A.A. Theodorou, I.S. Vrabas, A. Kyparos, M.G. Nikolaidis
Mitochondria are considered the major consumers of oxygen in the body (Pittman, 2016). Acetyl coenzyme-A is used in the Krebs cycle to produce ATP, NADH, FADH2 and carbon dioxide. Electrons from the NADH and FADH2 are then moved to the electron transport chain, which is the last step of aerobic respiration. The electron transport chain involves a series of redox reactions along four complexes (I-IV) on the inner mitochondrial membrane, where electrons pass rapidly from one complex to the next (Mailloux, 2015). At the end of the chain, the electrons reduce oxygen to water and produce a large amount of ATP from NADH.
Damage Control Surgery
Published in Ian Greaves, Keith Porter, Jeff Garner, Trauma Care Manual, 2021
Ian Greaves, Keith Porter, Jeff Garner
The resulting haemorrhagic hypovolaemia causes inability of oxygen and metabolites to be delivered to end organs, resulting in organ dys-function. Usually, during aerobic respiration 38 molecules of ATP are formed when glucose is metabolized; during anaerobic respiration only two molecules of ATP are formed. When an individual shivers, the purpose of shivering is to increase ATP production in order to generate heat, which subsequently warms the blood passing through the tissues. Therefore, during anaerobic metabolism there is a drop in body temperature, which further potentiates coagulopathy.7
The association between lactate dehydrogenase to serum albumin ratio and the 28-day mortality in patients with sepsis-associated acute kidney injury in intensive care: a retrospective cohort study
Published in Renal Failure, 2023
Minghao Liang, Xiuhong Ren, Di Huang, Zhishen Ruan, Xianhai Chen, Zhanjun Qiu
The enzyme LDH is involved in energy metabolism and converts pyruvate to lactate in cells. It has been shown that LDH is an independent predictor of prognosis in individuals with sepsis [20] and AKI [21]. Inflammation, metabolic recoding, RTEC apoptosis, and shock play essential roles in SA-AKI [7]. RTECs, the most metabolically active cells in the kidney, undergo metabolic recoding in SA-AKI. Although aerobic respiration is normally the main mechanism of cellular energy production, in SA-AKI, RTECs first undergo glycolysis to convert pyruvate to lactate [22]. LDH activity increases during this process. During SA-AKI, infiltration by inflammatory cells and the presence of large amounts of inflammatory factors lead to the deterioration of renal function [23], and apoptosis of RTECs leads to the release of lactate dehydrogenase, resulting in elevated lactate dehydrogenase levels.
α-Hederin inhibits the growth of lung cancer A549 cells in vitro and in vivo by decreasing SIRT6 dependent glycolysis
Published in Pharmaceutical Biology, 2021
Cong Fang, Yahui Liu, Lanying Chen, Yingying Luo, Yaru Cui, Ni Zhang, Peng Liu, Mengjing Zhou, Yongyan Xie
Reprogramming energy metabolism is a hallmark of cancer. Energy metabolism is the process in which energy is generated from nutrients, released, stored, and consumed by organisms or living cells. Energy metabolism is divided into glucose metabolism, protein metabolism, and fat metabolism. Under normal conditions, cells generate energy primarily via aerobic respiration. When the oxygen content is insufficient, cells perform glycolysis to generate energy. This process is called anaerobic respiration. Unlike normal cells, tumour cells generate energy primarily via glycolysis, even under aerobic conditions, a phenomenon known as the Warburg effect. Glycolytic capacity is characterized by rapid productivity and low efficiency. The rapid proliferation of tumour cells requires rapid energy consumption. Meanwhile, the lactic acid generated by glycolysis creates an acidic environment for tumour cells, which is conducive to their growth and leads to their rapid proliferation (Zhao et al. 2014; Potter et al. 2016). Sirtuin 6 (SIRT6) protein is a chromatin binding factor that was initially described as an inhibitor of gene instability (Mostoslavsky et al. 2006). During energy metabolism, SIRT6 regulates the fat and glucose metabolism, which is a key regulator of energy stress and is closely related to the process of tumour growth (Sebastián and Mostoslavsky 2015). With the metabolic profile used for energy production is elucidated, regulating tumour metabolism is a new therapeutic strategy to inhibit tumour growth (Zhang and Yang 2013).
Glutathione reductase and catalase as potential biomarkers for synergistic intoxication of pesticides in fish
Published in Biomarkers, 2019
Ankur Khare, Naina Chhawani, Kanchan Kumari
Contrary to LDH activity, a sudden decrease in SDH activity was seen in the study period in all the groups. Succinate dehydrogenase is the only mitochondrial metabolic enzyme and the only one which is involved in both TCA cycle and electron transport chain as it couples the conversion of succinate to fumarate with reduction of ubiquinone to quinone for energy generation. It is also associated with oxygen sensing and aerobic respiration in the tissues. The sharp decrease in SDH levels in this study justifies the fact that anaerobic respiration was favored in contrast to aerobic respiration due to the oxygen debts. This decreased level of SDH indicates inhibition of SDH at mitochondrial level alternatively enhancing different pathways for carbohydrate metabolism (Srivastava et al.2016). The oxygen debt experienced by fishes was much greater in carbaryl exposure in comparison to methyl parathion alone and synergistic effect of carbaryl and methyl parathion as reflected by the SDH activity. Contrary to increase in LDH activity, decrease in the activity of SDH was accounted which indicates that the metabolism of the fish body is shifting towards anaerobic respiration under stress condition caused by toxicants. A strong negative correlation of −0.91 was accounted between the increase in LDH and decrease in SDH activity, depicts that pesticides are capable of inducing oxidative stress. A significant and progressive increase in LDH serum was observed in entire study.