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Cancer Metastasis Reviews Jun 2019
Topics: Aerobiosis; Glycolysis; Humans; Hydrogen-Ion Concentration; Neoplasms
PubMed: 31069573
DOI: 10.1007/s10555-019-09798-1 -
Nutrients Aug 2020Beta-alanine supplementation (BA) has a positive impact on physical performance. However, evidence showing a benefit of this amino acid in aerobic-anaerobic transition... (Meta-Analysis)
Meta-Analysis
Beta-alanine supplementation (BA) has a positive impact on physical performance. However, evidence showing a benefit of this amino acid in aerobic-anaerobic transition zones is scarce and the results controversial. The aim of this systematic review and meta-analysis is to analyze the effects of BA supplementation on physical performance in aerobic-anaerobic transition zones. At the same time, the effect of different dosages and durations of BA supplementation were identified. The search was designed in accordance with the PRISMA guidelines for systematic reviews and meta-analyses and performed in Web of Science (WOS), Scopus, SPORTDiscus, PubMed, and MEDLINE between 2010 and 2020. The methodological quality and risk of bias were evaluated with the Cochrane Collaboration tool. The main variables were the Time Trial Test (TTT) and Time to Exhaustion (TTE) tests, the latter separated into the Limited Time Test (LTT) and Limited Distance Test (LDT). The analysis was carried out with a pooled standardized mean difference (SMD) through Hedges' g test (95% CI). Nineteen studies were included in the systematic review and meta-analysis, revealing a small effect for time in the TTT (SMD, -0.36; 95% CI, -0.87-0.16; I = 59%; = 0.010), a small effect for LTT (SMD, 0.25; 95% CI, -0.01-0.51; I = 0%; = 0.53), and a large effect for LDT (SMD, 4.27; 95% CI, -0.25-8.79; I = 94%; = 0.00001). BA supplementation showed small effects on physical performance in aerobic-anaerobic transition zones. Evidence on acute supplementation is scarce (one study); therefore, exploration of acute supplementation with different dosages and formats on physical performance in aerobic-anaerobic transition zones is needed.
Topics: Aerobiosis; Anaerobiosis; Dietary Supplements; Humans; Physical Functional Performance; Sports Nutritional Physiological Phenomena; beta-Alanine
PubMed: 32824885
DOI: 10.3390/nu12092490 -
Trends in Microbiology May 2021Ancient microbes invented biochemical mechanisms and assembled core metabolic pathways on an anoxic Earth. Molecular oxygen appeared far later, forcing microbes to... (Review)
Review
Ancient microbes invented biochemical mechanisms and assembled core metabolic pathways on an anoxic Earth. Molecular oxygen appeared far later, forcing microbes to devise layers of defensive tactics that fend off the destructive actions of both reactive oxygen species (ROS) and oxygen itself. Recent work has pinpointed the enzymes that ROS attack, plus an array of clever protective strategies that abet the well known scavenging systems. Oxygen also directly damages the low-potential metal centers and radical-based mechanisms that optimize anaerobic metabolism; therefore, committed anaerobes have evolved customized tactics that defend these various enzymes from occasional oxygen exposure. Thus a more comprehensive, detailed, and surprising view of oxygen toxicity is coming into view.
Topics: Aerobiosis; Anaerobiosis; Bacteria; Biological Evolution; Oxidative Stress; Oxygen; Reactive Oxygen Species
PubMed: 33109411
DOI: 10.1016/j.tim.2020.10.001 -
Biotechnology and Bioengineering Dec 2020Aerobic granular sludge (AGS) technology allows simultaneous nitrogen, phosphorus, and carbon removal in compact wastewater treatment processes. To operate, design, and...
Aerobic granular sludge (AGS) technology allows simultaneous nitrogen, phosphorus, and carbon removal in compact wastewater treatment processes. To operate, design, and model AGS reactors, it is essential to properly understand the diffusive transport within the granules. In this study, diffusive mass transfer within full-scale and lab-scale AGS was characterized with nuclear magnetic resonance (NMR) methods. Self-diffusion coefficients of water inside the granules were determined with pulsed-field gradient NMR, while the granule structure was visualized with NMR imaging. A reaction-diffusion granule-scale model was set up to evaluate the impact of heterogeneous diffusion on granule performance. The self-diffusion coefficient of water in AGS was ∼70% of the self-diffusion coefficient of free water. There was no significant difference between self-diffusion in AGS from full-scale treatment plants and from lab-scale reactors. The results of the model showed that diffusional heterogeneity did not lead to a major change of flux into the granule (<1%). This study shows that differences between granular sludges and heterogeneity within granules have little impact on the kinetic properties of AGS. Thus, a relatively simple approach is sufficient to describe mass transport by diffusion into the granules.
Topics: Aerobiosis; Sewage; Waste Disposal, Fluid; Water Purification
PubMed: 32725888
DOI: 10.1002/bit.27522 -
Philosophical Transactions of the Royal... Sep 2016Flapping flight is energetically more costly than running, although it is less costly to fly a given body mass a given distance per unit time than it is for a similar... (Review)
Review
Flapping flight is energetically more costly than running, although it is less costly to fly a given body mass a given distance per unit time than it is for a similar mass to run the same distance per unit time. This is mainly because birds can fly faster than they can run. Oxygen transfer and transport are enhanced in migrating birds compared with those in non-migrators: at the gas-exchange regions of the lungs the effective area is greater and the diffusion distance smaller. Also, migrating birds have larger hearts and haemoglobin concentrations in the blood, and capillary density in the flight muscles tends to be higher. Species like bar-headed geese migrate at high altitudes, where the availability of oxygen is reduced and the energy cost of flapping flight increased compared with those at sea level. Physiological adaptations to these conditions include haemoglobin with a higher affinity for oxygen than that in lowland birds, a greater effective ventilation of the gas-exchange surface of the lungs and a greater capillary-to-muscle fibre ratio. Migrating birds use fatty acids as their source of energy, so they have to be transported at a sufficient rate to meet the high demand. Since fatty acids are insoluble in water, birds maintain high concentrations of fatty acid-binding proteins to transport fatty acids across the cell membrane and within the cytoplasm. The concentrations of these proteins, together with that of a key enzyme in the β-oxidation of fatty acids, increase before migration.This article is part of the themed issue 'Moving in a moving medium: new perspectives on flight'.
Topics: Aerobiosis; Animal Migration; Animals; Birds; Energy Metabolism; Flight, Animal
PubMed: 27528774
DOI: 10.1098/rstb.2015.0384 -
Microbiology (Reading, England) Jun 2015Carnitine is a quaternary amine compound found at high concentration in animal tissues, particularly muscle, and is most well studied for its contribution to fatty acid... (Review)
Review
Carnitine is a quaternary amine compound found at high concentration in animal tissues, particularly muscle, and is most well studied for its contribution to fatty acid transport into mitochondria. In bacteria, carnitine is an important osmoprotectant, and can also enhance thermotolerance, cryotolerance and barotolerance. Carnitine can be transported into the cell or acquired from metabolic precursors, where it can serve directly as a compatible solute for stress protection or be metabolized through one of a few distinct pathways as a nutrient source. In this review, we summarize what is known about carnitine physiology and metabolism in bacteria. In particular, recent advances in the aerobic and anaerobic metabolic pathways as well as the use of carnitine as an electron acceptor have addressed some long-standing questions in the field.
Topics: Aerobiosis; Anaerobiosis; Animals; Bacterial Physiological Phenomena; Carnitine; Cold Temperature; Electron Transport; Hot Temperature; Hydrostatic Pressure; Metabolic Networks and Pathways; Osmotic Pressure; Stress, Physiological
PubMed: 25787873
DOI: 10.1099/mic.0.000080 -
Microbiology and Molecular Biology... Sep 1999In the late 1970s, on the basis of rRNA phylogeny, Archaea (archaebacteria) was identified as a distinct domain of life besides Bacteria (eubacteria) and Eucarya. Though... (Review)
Review
In the late 1970s, on the basis of rRNA phylogeny, Archaea (archaebacteria) was identified as a distinct domain of life besides Bacteria (eubacteria) and Eucarya. Though forming a separate domain, Archaea display an enormous diversity of lifestyles and metabolic capabilities. Many archaeal species are adapted to extreme environments with respect to salinity, temperatures around the boiling point of water, and/or extremely alkaline or acidic pH. This has posed the challenge of studying the molecular and mechanistic bases on which these organisms can cope with such adverse conditions. This review considers our cumulative knowledge on archaeal mechanisms of primary energy conservation, in relationship to those of bacteria and eucarya. Although the universal principle of chemiosmotic energy conservation also holds for Archaea, distinct features have been discovered with respect to novel ion-transducing, membrane-residing protein complexes and the use of novel cofactors in bioenergetics of methanogenesis. From aerobically respiring Archaea, unusual electron-transporting supercomplexes could be isolated and functionally resolved, and a proposal on the organization of archaeal electron transport chains has been presented. The unique functions of archaeal rhodopsins as sensory systems and as proton or chloride pumps have been elucidated on the basis of recent structural information on the atomic scale. Whereas components of methanogenesis and of phototrophic energy transduction in halobacteria appear to be unique to Archaea, respiratory complexes and the ATP synthase exhibit some chimeric features with respect to their evolutionary origin. Nevertheless, archaeal ATP synthases are to be considered distinct members of this family of secondary energy transducers. A major challenge to future investigations is the development of archaeal genetic transformation systems, in order to gain access to the regulation of bioenergetic systems and to overproducers of archaeal membrane proteins as a prerequisite for their crystallization.
Topics: Aerobiosis; Archaea; Electron Transport; Energy Metabolism; Euryarchaeota; Light; Protons
PubMed: 10477309
DOI: 10.1128/MMBR.63.3.570-620.1999 -
Biochimica Et Biophysica Acta.... Nov 2020Ubiquinone is an important component of the electron transfer chains in proteobacteria and eukaryotes. The biosynthesis of ubiquinone requires multiple steps, most of... (Review)
Review
Ubiquinone is an important component of the electron transfer chains in proteobacteria and eukaryotes. The biosynthesis of ubiquinone requires multiple steps, most of which are common to bacteria and eukaryotes. Whereas the enzymes of the mitochondrial pathway that produces ubiquinone are highly similar across eukaryotes, recent results point to a rather high diversity of pathways in bacteria. This review focuses on ubiquinone in bacteria, highlighting newly discovered functions and detailing the proteins that are known to participate to its biosynthetic pathways. Novel results showing that ubiquinone can be produced by a pathway independent of dioxygen suggest that ubiquinone may participate to anaerobiosis, in addition to its well-established role for aerobiosis. We also discuss the supramolecular organization of ubiquinone biosynthesis proteins and we summarize the current understanding of the evolution of the ubiquinone pathways relative to those of other isoprenoid quinones like menaquinone and plastoquinone.
Topics: Aerobiosis; Anaerobiosis; Bacteria; Biosynthetic Pathways; Electron Transport; Ubiquinone
PubMed: 32663475
DOI: 10.1016/j.bbabio.2020.148259 -
Minerva Anestesiologica Apr 2003The detection of tissue hypoxia and its correction is one of the aim of the hemodynamic monitoring. Classical hemodynamic variable often fail to achieve this goal.... (Review)
Review
The detection of tissue hypoxia and its correction is one of the aim of the hemodynamic monitoring. Classical hemodynamic variable often fail to achieve this goal. Lactate measurements may be a good indicator of tissue hypoxia. Selected review of the articles on lactate in critically ill patients. Tissue hypoxia is associated with an increase in blood lactate levels. However lactate can also be produced in aerobic conditions, in inflammated tissues, and lactate clearance is often decreased in critically ill patients. Whatever its origin, blood lactate levels have a strong predictive value. The interpretation of blood lactate levels is difficult. Nevertheless, monitoring blood lactate levels can be useful to detect tissue hypoxia and to monitor the effects of therapy.
Topics: Acidosis, Lactic; Aerobiosis; Anaerobiosis; Humans; Lactates; Prognosis; Sepsis
PubMed: 12766720
DOI: No ID Found -
Current Opinion in Biotechnology Jun 2001Novel dehalogenases have been identified recently in various bacteria that utilise halogenated substrates. X-ray studies and sequence analysis have revealed insight into... (Review)
Review
Novel dehalogenases have been identified recently in various bacteria that utilise halogenated substrates. X-ray studies and sequence analysis have revealed insight into the molecular mechanisms of hydrolytic dehalogenases. Furthermore, genetic and biochemical studies have indicated that reductive dehalogenases are extra-cytoplasmic corrinoid-containing iron-sulphur proteins. Sequence analysis and mutagenesis studies indicate that several dehalogenases are homologous to enzymes that carry out transformations on non-halogenated substrates.
Topics: Aerobiosis; Anaerobiosis; Bacteria; Bacterial Physiological Phenomena; Biodegradation, Environmental; Catalysis; Hydrocarbons, Halogenated; Hydrolases
PubMed: 11404103
DOI: 10.1016/s0958-1669(00)00208-1