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Proceedings of the National Academy of... Aug 2011Aerobic respiration in bacteria, Archaea, and mitochondria is performed by oxygen reductase members of the heme-copper oxidoreductase superfamily. These enzymes are...
Aerobic respiration in bacteria, Archaea, and mitochondria is performed by oxygen reductase members of the heme-copper oxidoreductase superfamily. These enzymes are redox-driven proton pumps which conserve part of the free energy released from oxygen reduction to generate a proton motive force. The oxygen reductases can be divided into three main families based on evolutionary and structural analyses (A-, B- and C-families), with the B- and C-families evolving after the A-family. The A-family utilizes two proton input channels to transfer protons for pumping and chemistry, whereas the B- and C-families require only one. Generally, the B- and C-families also have higher apparent oxygen affinities than the A-family. Here we use whole cell proton pumping measurements to demonstrate differential proton pumping efficiencies between representatives of the A-, B-, and C-oxygen reductase families. The A-family has a coupling stoichiometry of 1 H(+)/e(-), whereas the B- and C-families have coupling stoichiometries of 0.5 H(+)/e(-). The differential proton pumping stoichiometries, along with differences in the structures of the proton-conducting channels, place critical constraints on models of the mechanism of proton pumping. Most significantly, it is proposed that the adaptation of aerobic respiration to low oxygen environments resulted in a concomitant reduction in energy conservation efficiency, with important physiological and ecological consequences.
Topics: Adaptation, Physiological; Aerobiosis; Bacteria; Hydrogen-Ion Concentration; Oxygen; Proton Pumps; Rhodobacter capsulatus
PubMed: 21844375
DOI: 10.1073/pnas.1018958108 -
Environmental Technology Sep 2021This paper demonstrates modelling of the aerobic granular sludge (AGS) process with the pseudo-analytical solutions (PAS) of a biofilm model. A MATLAB programmed...
This paper demonstrates modelling of the aerobic granular sludge (AGS) process with the pseudo-analytical solutions (PAS) of a biofilm model. A MATLAB programmed graphical user interface platform was developed to facilitate the model calculation and access. Model calibration and validation were carried out through using experimental data collected from a granular sludge sequencing batch reactor operation. The experimental and modelling results identified the distribution of heterotrophs and nitrifiers on the AGS and its contribution to the performance of wastewater treatment. The model could describe multi-species biofilms according to the distinguishing features among the three levels of PAS models. The models demonstrated increasing degrees of interaction (no interaction, competition for nitrogen and layering and protection) between heterotrophs and nitrifiers. Modelling the AGS process using PAS increases the accessibility of the simulation of multiple species in both biofilm and suspended biomass.
Topics: Aerobiosis; Biofilms; Bioreactors; Nitrogen; Sewage; Waste Disposal, Fluid
PubMed: 32085686
DOI: 10.1080/09593330.2020.1733673 -
Proceedings of the National Academy of... Jan 2021Aerobic glycolysis (AG), that is, the nonoxidative metabolism of glucose, contributes significantly to anabolic pathways, rapid energy generation, task-induced activity,...
Aerobic glycolysis (AG), that is, the nonoxidative metabolism of glucose, contributes significantly to anabolic pathways, rapid energy generation, task-induced activity, and neuroprotection; yet high AG is also associated with pathological hallmarks such as amyloid-β deposition. An important yet unresolved question is whether and how the metabolic benefits and risks of brain AG is structurally shaped by connectome wiring. Using positron emission tomography and magnetic resonance imaging techniques as well as computational models, we investigate the relationship between brain AG and the macroscopic connectome. Specifically, we propose a weighted regional distance-dependent model to estimate the total axonal projection length of a brain node. This model has been validated in a macaque connectome derived from tract-tracing data and shows a high correspondence between experimental and estimated axonal lengths. When applying this model to the human connectome, we find significant associations between the estimated total axonal projection length and AG across brain nodes, with higher levels primarily located in the default-mode and prefrontal regions. Moreover, brain AG significantly mediates the relationship between the structural and functional connectomes. Using a wiring optimization model, we find that the estimated total axonal projection length in these high-AG regions exhibits a high extent of wiring optimization. If these high-AG regions are randomly rewired, their total axonal length and vulnerability risk would substantially increase. Together, our results suggest that high-AG regions have expensive but still optimized wiring cost to fulfill metabolic requirements and simultaneously reduce vulnerability risk, thus revealing a benefit-risk balancing mechanism in the human brain.
Topics: Adult; Aerobiosis; Brain; Connectome; Databases, Factual; Female; Glycolysis; Humans; Magnetic Resonance Imaging; Male; Nerve Net; Neural Pathways; Positron-Emission Tomography
PubMed: 33443160
DOI: 10.1073/pnas.2013232118 -
Journal - Water Pollution Control... Mar 1975
Topics: Aerobiosis; Oxygen Consumption; Sewage; Water Microbiology
PubMed: 1142546
DOI: No ID Found -
Environmental Research Mar 2023In order to solve nitrogen pollution in environmental water, two heterotrophic nitrifying and aerobic denitrifying strains isolated from acid paddy soil were identified...
In order to solve nitrogen pollution in environmental water, two heterotrophic nitrifying and aerobic denitrifying strains isolated from acid paddy soil were identified as Achromobacter sp. strain HNDS-1 and Enterobacter sp. strain HNDS-6 respectively. Strain HNDS-1 and strain HNDS-6 exhibited amazing ability to nitrogen removal. When (NH)SO, KNO, NaNO were used as nitrogen resource respectively, the NH-N, NO-N, NO-N removal efficiencies of strain HNDS-1 were 93.31%, 89.47%, and 100% respectively, while those of strain HNDS-6 were 82.39%, 96.92%, and 100%. And both of them could remove mixed nitrogen effectively in low C/N (C/N = 5). Strain HNDS-1 could remove 76.86% NH-N and 75.13% NO-N. And strain HNDS-6 can remove 65.07% NH-N and 78.21% NO-N. A putative ammonia monooxygenase, nitrite reductase, nitrate reductase, assimilatory nitrate reductase, nitrate/nitrite transport protein and nitric oxide reductase of strain HNDS-1, while hydroxylamine reductase, nitrite reductase, nitrate reductase, assimilatory nitrate reductase, nitrate/nitrite transport protein, and nitric oxide reductase of strain HNDS-6 were identified by genomic analysis. DNA-SIP analysis showed that genes Nxr, narG, nirK, norB, nosZ were involved in nitrogen removal pathway, which indicates that the denitrification pathway of strain HNDS-1 and strain HNDS-6 was NO→NO→NO→NO→N during NH-N removal process. And the nitrification pathway of strain HNDS-1 and strain HNDS-6 was NO→NO, but the nitrification pathway of NH→ NO needs further studies.
Topics: Achromobacter; Aerobiosis; Denitrification; Enterobacter; Nitrates; Nitrification; Nitrite Reductases; Nitrites; Nitrogen; Nitrogen Dioxide
PubMed: 36621544
DOI: 10.1016/j.envres.2023.115240 -
Azolla pinnata, Aspergillus terreus and Eisenia fetida for enhancing agronomic value of paddy straw.Scientific Reports Feb 2019In the present study rice straw (R, control) was mixed with Cowdung (C), Azolla (A) and cellulolytic fungus Aspergillus terreus (F) in different combinations viz. RC,...
In the present study rice straw (R, control) was mixed with Cowdung (C), Azolla (A) and cellulolytic fungus Aspergillus terreus (F) in different combinations viz. RC, RA, RF, RCF, RCA, RFA and RCFA and subjected to aerobic composting (Acom) and vermicomposting (Vcom - with Eisenia fetida). It was found that addition of azolla and cattledung to two parts straw(RCA-666: 314:20 g) caused fastest degradation (105 days), gave maximum population buildup of E. fetida (cocoons, hatchlings and worm biomass), highest decline in pH, EC, TOC and C/N ratio and maximum increase over control in N(17.72%), P(44.64%), K(43.17%), H (7.93%), S (14.85%), Ca(10.16%), Na(145.97%), Fe(68.56%), Zn(12.10%) and Cu(32.24%). Rice straw (R) took longest time for degradation i.e. 120 and 140 days and had lowest content of nutrients in Vcom as well as Acom group. RCFA was also converted into Vcom at the same time but other parameters were less than RCA except for highest content of B (19.87%), Mg(21.27%) and Mn (5.58%). Bioconversion of three parts straw (RCA-735:245:20 g) was also faster (110 days) with vermicomposting than all the mixtures of Acom group (130-140 days) but nutrient content was slightly less than RCA with 2 parts straw. The results show that azolla reduces dependence on cattledung for recycling the carbon rich rice straw and enhances its agronomic value.
Topics: Aerobiosis; Aspergillus; Biomass; Carbon; Composting; Ferns; Oryza; Recycling
PubMed: 30718700
DOI: 10.1038/s41598-018-37880-1 -
Journal of Theoretical Biology Sep 2019The lifeless earth was formed around 4.5 billion years ago and the first anaerobic unicellular "organisms" may have appeared half a billion years later. Despite...
The lifeless earth was formed around 4.5 billion years ago and the first anaerobic unicellular "organisms" may have appeared half a billion years later. Despite subsequent prokaryotes (bacteria and archaea) evolving quite complex biochemistry and some eukaryote characteristics, the transition from unicellular prokaryotes to multicellular, aerobic eukaryotes took a further 2.5 billion years to begin. The key factor or factors that eventually caused this long-delayed transition is a question that has been a focus of considerable research and a topic of discussion over many years. On the basis of the extensive literature available and consideration of some of the characteristics that distinguish multicellular eukaryotes from prokaryotes, it is proposed that, as well as the development of oxygenic photosynthesis producing high levels of environmental oxygen and the formation of vital organelles such as aerobic adenosine triphosphate-generating mitochondria, the concurrent evolution of the L-ascorbic acid redox system should be considered as a key factor that led to the evolution of multicellular eukaryotes and it remains vitally involved in the maintenance of multicellularity and many other eukaryote characteristics.
Topics: Aerobiosis; Ascorbic Acid; Eukaryotic Cells; Evolution, Molecular; Photosynthesis; Plants
PubMed: 31170405
DOI: 10.1016/j.jtbi.2019.06.001 -
Nihon Rinsho. Japanese Journal of... Sep 2000
Review
Topics: Adenosine Triphosphate; Aerobiosis; Anaerobiosis; Energy Metabolism; Exercise Test; Heart Rate; Humans; Oxygen Consumption; Physical Endurance; Physical Examination; Physical Fitness
PubMed: 11085107
DOI: No ID Found -
Proceedings of the National Academy of... Nov 2010Molecular oxygen (O(2)) is the second most abundant gas in the Earth's atmosphere, but in many natural environments, its concentration is reduced to low or even...
Molecular oxygen (O(2)) is the second most abundant gas in the Earth's atmosphere, but in many natural environments, its concentration is reduced to low or even undetectable levels. Although low-oxygen-adapted organisms define the ecology of low-oxygen environments, their capabilities are not fully known. These capabilities also provide a framework for reconstructing a critical period in the history of life, because low, but not negligible, atmospheric oxygen levels could have persisted before the "Great Oxidation" of the Earth's surface about 2.3 to 2.4 billion years ago. Here, we show that Escherichia coli K-12, chosen for its well-understood biochemistry, rapid growth rate, and low-oxygen-affinity terminal oxidase, grows at oxygen levels of ≤ 3 nM, two to three orders of magnitude lower than previously observed for aerobes. Our study expands both the environmental range and temporal history of aerobic organisms.
Topics: Aerobiosis; Escherichia coli K12; Models, Biological; Oxygen
PubMed: 20974919
DOI: 10.1073/pnas.1013435107 -
Comptes Rendus Hebdomadaires Des... Sep 1961
Topics: Aerobiosis; Anaerobiosis; Oxygen; Yeasts
PubMed: 14009636
DOI: No ID Found