Biology of microbes
Philip A. Geis in Cosmetic Microbiology, 2006
Anaerobic respiration. Many students of microbiology consider anaerobic processes to be synonymous with fermentation. In fact, many anaerobic processes still may have ATP formed as a result of oxidative phosphorylations if they replace only the terminal electron acceptor oxygen with an inorganic form of oxygen. For example, nitrate (NO3−), sulfate (SO4−), and carbonate (CO3−) all serve as inorganic salts of oxygen in order for anaerobic respiration (the use of a cytochrome chain) to take place. Use of the respiration term in microbiology does not mean that a microbe breathes air. Instead, it means that a microbe has a cytochrome chain capable of oxidative phosphorylation. In the case of anaerobic respiration, we use inorganic salts of oxygen rather than oxygen itself as the terminal electron acceptor.
Bacteria
Julius P. Kreier in 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.
Inflammation and Infection
Karl H. Pang, Nadir I. Osman, James W.F. Catto, Christopher R. Chapple in Basic Urological Sciences, 2021
Pathophysiology:Endotoxins released by gram-negative bacteria.Inflammatory cells infiltration (neutrophils, macrophages, plasma cells).Cytokine release: TNFα, IL-2, IL-6, IL-8.Activation of kinin complement and the fibrinolytic system.Anaerobic respiration and lactic acid accumulation.Metabolic acidosis → vasoconstriction and cellular membrane dysfunctionMicrovascular injury and tissue ischaemia.Hypotension (shock) from cytokine-mediated vasodilatation.
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).
Vascular injury at laparoscopy: a guide to management
Published in Journal of Obstetrics and Gynaecology, 2018
Victoria Asfour, Edward Smythe, Rizwan Attia
Damage control resuscitation tolerates up to moderate hypotension (systolic of 90 mmHg) with judicious replacement of fluids and blood. Traumatic coagulopathy may be prevented with proactive replacement of platelets and clotting factors, calcium supplementation and red cell transfusions. Acidosis is strongly associated with adverse outcomes. It occurs when the peripheral tissues are hypo-perfused. There is a conversion to anaerobic respiration producing lactate (acidosis). Acidosis directly affects myocardial function leading to a low cardiac output state. Hypothermia exacerbates acidosis, promotes coagulopathy, arrhythmias, enzymatic activity and further reduces cardiac output (Sandadi et al. 2010; Miller 2013). Hypothermia can be avoided by using warmed intravenous fluids, use of the bear hugger blanket, a prompt diagnosis and the repair of the bleeding point (Figures 1–3).
Targeted pharmacotherapy for ischemia reperfusion injury in acute myocardial infarction
Published in Expert Opinion on Pharmacotherapy, 2020
Amit Rout, Udaya S Tantry, Marko Novakovic, Ajaypaul Sukhi, Paul A Gurbel
Myocardial IRI is a complex process that involves myocardial tissue and components in the circulation including, leukocytes, platelets, and released microparticles. During MI, the absence of oxygen following obstruction of the coronary artery switches cell metabolism to anaerobic respiration leading to a cascade of pathophysiologic changes. Anaerobic respiration results in the accumulation of lactic acid inside the cells and metabolic acidosis. This induces failure of Na+-K+-ATPase pumps, causing increased intracellular accumulation of Na+, leading to attenuation of activity of Na+-H+ pumps and Ca2+-ATPase pumps in the endoplasmic reticulum, which then limits calcium reuptake. Finally, the cellular accumulation of H+, and Na+ causes hyperosmolality, increased water retention in the cytoplasm, edema, decreased cellular pH, and eventually impaired cellular enzyme activity. Importantly, cellular acidosis and increased Ca2+ concentration culminate in the opening of the mitochondrial permeability transition pore (mPTP) leading to myocardial ischemia and cardiomyocyte death [1,3].
Related Knowledge Centers
- Anaerobic Organism
- Cellular Respiration
- Electron Transport Chain
- Fumaric Acid
- Nitrate
- Oxidizing Agent
- Oxygen
- Sulfate
- Allotropes of Oxygen
- Aerobic Organism