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Biochimica Et Biophysica Acta Feb 2013Behind the versatile nature of prokaryotic energy metabolism is a set of redox proteins having a highly modular character. It has become increasingly recognized that a... (Review)
Review
Behind the versatile nature of prokaryotic energy metabolism is a set of redox proteins having a highly modular character. It has become increasingly recognized that a limited number of redox modules or building blocks appear grouped in different arrangements, giving rise to different proteins and functionalities. This modularity most likely reveals a common and ancient origin for these redox modules, and is obviously reflected in similar energy conservation mechanisms. The dissimilation of sulfur compounds was probably one of the earliest biological strategies used by primitive organisms to obtain energy. Here, we review some of the redox proteins involved in dissimilatory sulfur metabolism, focusing on sulfate reducing organisms, and highlight links between these proteins and others involved in different processes of anaerobic respiration. Noteworthy are links to the complex iron-sulfur molybdoenzyme family, and heterodisulfide reductases of methanogenic archaea. We discuss how chemiosmotic and electron bifurcation/confurcation may be involved in energy conservation during sulfate reduction, and how introduction of an additional module, multiheme cytochromes c, opens an alternative bioenergetic strategy that seems to increase metabolic versatility. Finally, we highlight new families of heterodisulfide reductase-related proteins from non-methanogenic organisms, which indicate a widespread distribution for these protein modules and may indicate a more general involvement of thiol/disulfide conversions in energy metabolism. This article is part of a Special Issue entitled: The evolutionary aspects of bioenergetic systems.
Topics: Aerobiosis; Archaea; Biological Evolution; Sulfur
PubMed: 22982583
DOI: 10.1016/j.bbabio.2012.09.001 -
Journal of Breath Research Jan 2015Mammalian methanogenesis is widely considered to be an exclusive sign of anaerobic microbial activity in the gastrointestinal tract. This commonly held view was... (Review)
Review
Mammalian methanogenesis is widely considered to be an exclusive sign of anaerobic microbial activity in the gastrointestinal tract. This commonly held view was challenged, however, when in vitro and in vivo investigations demonstrated the possibility of nonmicrobial methane formation in aerobic organisms, in plants and animals. The aim of this review is to discuss the available literature data on the biological role of methane. When we evaluate the significance of methane generation in the mammalian physiology, the question may be examined: is it a gas mediator? Overall the data do not fully support the gasotransmitter concept, but they do support the notion that methane liberation may be linked to redox regulation and may be connected with hypoxic events leading to, or associated with a mitochondrial dysfunction. In this respect, the available information suggests that hypoxia-induced methane generation may be a necessary phenomenon of aerobic life, and perhaps a surviving evolutionary trait in the eukaryote cell.
Topics: Aerobiosis; Animals; Biological Evolution; Gasotransmitters; Mammals; Methane; Oxidation-Reduction
PubMed: 25624411
DOI: 10.1088/1752-7155/9/1/014001 -
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 -
Molecular and Cellular Biochemistry Dec 2005The re-emergence of interest in intermediary metabolism and the development of metabolomics in relation to cancer and other diseases provide a timely reason to revisit... (Review)
Review
The re-emergence of interest in intermediary metabolism and the development of metabolomics in relation to cancer and other diseases provide a timely reason to revisit issues of tumour cell metabolism. In this review, we address the issue of the role of high aerobic glycolysis, which is commonly associated with the metabolism of many tumour cells. The concept presented emphasises the importance of the glycolysis-citrate-lipogenesis pathway in providing the synthetic and bioenergetic requirements that are essential for the growth and proliferation of tumour cells. We hope that our discussion will be informative and instructive, and will stimulate interest and research regarding the intermediary metabolism and its regulation in tumour cells. We express our appreciation to the many pioneering and contemporary researchers whose studies provide much of the basis for this presentation.
Topics: Aerobiosis; Citric Acid; Glucose; Glycolysis; Lipogenesis; Neoplasms
PubMed: 16511951
DOI: 10.1007/s11010-005-8841-8 -
FEMS Microbiology Reviews Nov 2002The last few decades have seen a steady increase in the global production and utilisation of the alkenylbenzene, styrene. The compound is of major importance in the... (Review)
Review
The last few decades have seen a steady increase in the global production and utilisation of the alkenylbenzene, styrene. The compound is of major importance in the petrochemical and polymer-processing industries, which can contribute to the pollution of natural resources via the release of styrene-contaminated effluents and off-gases. This is a cause for some concern as human over-exposure to styrene, and/or its early catabolic intermediates, can have a range of destructive health effects. These features have prompted researchers to investigate routes of styrene degradation in microorganisms, given the potential application of these organisms in bioremediation/biodegradation strategies. This review aims to examine the recent advances which have been made in elucidating the underlying biochemistry, genetics and physiology of microbial styrene catabolism, identifying areas of interest for the future and highlighting the potential industrial importance of individual catabolic pathway enzymes.
Topics: Aerobiosis; Anaerobiosis; Bacteria; Biodegradation, Environmental; Biological Transport; Enzymes; Filtration; Fungi; Industrial Waste; Models, Molecular; Operon; Pseudomonas; Sequence Homology, Nucleic Acid; Styrene
PubMed: 12413667
DOI: 10.1111/j.1574-6976.2002.tb00622.x -
Journal of Physiology and Pharmacology... Jun 2018Currently, literature has accumulated great knowledge over the effect of exercise on the neurotrophin named brain derived neurotrophic factor (BDNF) and its role in... (Review)
Review
Currently, literature has accumulated great knowledge over the effect of exercise on the neurotrophin named brain derived neurotrophic factor (BDNF) and its role in neuronal plasticity. However, there is no enough discussion about how the exercise is related to enrichment of BDNF in specific metabolic properties. This review provides the current evidences regarding aerobic metabolism relation to BDNF concentrations in healthy individuals. A PICOS strategy was applied considering the mesh terms for: P - healthy subjects; I - physical exercise; C - aerobic metabolism demands; O - BDNF concentrations; S - before and after aerobic exercise; on PubMed, Scopus and Medline databases. Studies presenting at least one session the exercise with reports of BDNF analysis before and after were included. Reviews, letters, case-reports, articles not written in English, non- published or involving non-healthy populations were excluded. Compiling results, it was possible to observe a close interaction between different aerobic energy demands from the exercise models and the responses of BDNF, suggesting thus that increases in BDNF concentrations are associated to the amount of aerobic energy required by exercise in a dose-dependent manner. Moreover, the dynamics of BDNF synthesis and reuptake resemble the functioning of the metabolic systems of aerobic energy generation, with which they share a co-transcriptional factor dependence.
Topics: Aerobiosis; Brain; Brain-Derived Neurotrophic Factor; Exercise; Humans; Neuronal Plasticity
PubMed: 30342429
DOI: 10.26402/jpp.2018.3.12 -
Water Research Nov 2020The settling behavior of aerobic granular sludge (AGS) in full-scale reactors is different from the settling of normal activated sludge. Current activated sludge models...
The settling behavior of aerobic granular sludge (AGS) in full-scale reactors is different from the settling of normal activated sludge. Current activated sludge models lack the features to describe the segregation of granules based on size during the settling process. This segregation plays an important role in the granulation process and therefore a better understanding of the settling is essential. The goal of this study was to model and evaluate the segregation of different granule sizes during settling and feeding in full-scale aerobic granular sludge reactors. Hereto the Patwardhan and Tien model was used. This model is an implementation of the Richardson and Zaki model, allowing for multiple classes of particles. To create the granular settling model, the most relevant parameters were identified using aerobic granular sludge from different full-scale Nereda® reactors. The settling properties of individual granules were measured as was the bulk behavior of granular sludge beds with uniform granular sludge particles. The obtained parameters were combined in a model containing multiple granule classes, which then was validated for granular sludge settling in a full-scale Nereda® reactor. In practice a hydraulic selection pressure is used to select for granular sludge. Under the same hydraulic selection pressure the model predicted that different stable granular size distributions can occur. This indicates that granular size distribution control would need a different mechanism then the hydraulic selection pressure alone. This model can be used to better understand and optimize operational parameters of AGS reactors that depend on granular sludge size, like biological nutrient removal. Furthermore insights from this model can also be used in the development of continuously fed AGS systems.
Topics: Aerobiosis; Bioreactors; Sewage; Waste Disposal, Fluid
PubMed: 32891906
DOI: 10.1016/j.watres.2020.116135 -
Biochimica Et Biophysica Acta Mar 2016Aerobic respiratory chains from all life kingdoms are composed by several complexes that have been deeply characterized in their isolated form. These membranous... (Review)
Review
Aerobic respiratory chains from all life kingdoms are composed by several complexes that have been deeply characterized in their isolated form. These membranous complexes link the oxidation of reducing substrates to the reduction of molecular oxygen, in a process that conserves energy by ion translocation between both sides of the mitochondrial or prokaryotic cytoplasmatic membranes. In recent years there has been increasing evidence that those complexes are organized as supramolecular structures, the so-called supercomplexes and respirasomes, being available for eukaryotes strong data namely obtained by electron microscopy and single particle analysis. A parallel study has been developed for prokaryotes, based on blue native gels and mass spectrometry analysis, showing that in these more simple unicellular organisms such supercomplexes also exist, involving not only typical aerobic-respiration associated complexes, but also anaerobic-linked enzymes. After a short overview of the data on eukaryotic supercomplexes, we will analyse comprehensively the different types of prokaryotic aerobic respiratory supercomplexes that have been thus far suggested, in both bacteria and archaea. This article is part of a Special Issue entitled Organization and dynamics of bioenergetic systems in bacteria, edited by Prof Conrad Mullineaux.
Topics: Aerobiosis; Bacteria; Bacterial Proteins; Cell Membrane; Electron Transport; Electron Transport Chain Complex Proteins; Proton-Motive Force
PubMed: 26546715
DOI: 10.1016/j.bbabio.2015.11.001 -
The Journal of Biological Chemistry Aug 2010Aerobic organisms are faced with a dilemma. Environmental iron is found primarily in the relatively inert Fe(III) form, whereas the more metabolically active ferrous... (Review)
Review
Aerobic organisms are faced with a dilemma. Environmental iron is found primarily in the relatively inert Fe(III) form, whereas the more metabolically active ferrous form is a strong pro-oxidant. This conundrum is solved by the redox cycling of iron between Fe(III) and Fe(II) at every step in the iron metabolic pathway. As a transition metal ion, iron can be "metabolized" only by this redox cycling, which is catalyzed in aerobes by the coupled activities of ferric iron reductases (ferrireductases) and ferrous iron oxidases (ferroxidases).
Topics: Aerobiosis; Animals; Ceruloplasmin; FMN Reductase; Humans; Ion Transport; Iron; Oxidation-Reduction
PubMed: 20522542
DOI: 10.1074/jbc.R110.113217 -
International Journal of Environmental... Jan 2009Aromatic compounds are among the most prevalent and persistent pollutants in the environment. Petroleum-contaminated soil and sediment commonly contain a mixture of... (Review)
Review
Aromatic compounds are among the most prevalent and persistent pollutants in the environment. Petroleum-contaminated soil and sediment commonly contain a mixture of polycyclic aromatic hydrocarbons (PAHs) and heterocyclic aromatics. Aromatics derived from industrial activities often have functional groups such as alkyls, halogens and nitro groups. Biodegradation is a major mechanism of removal of organic pollutants from a contaminated site. This review focuses on bacterial degradation pathways of selected aromatic compounds. Catabolic pathways of naphthalene, fluorene, phenanthrene, fluoranthene, pyrene, and benzo[a]pyrene are described in detail. Bacterial catabolism of the heterocycles dibenzofuran, carbazole, dibenzothiophene, and dibenzodioxin is discussed. Bacterial catabolism of alkylated PAHs is summarized, followed by a brief discussion of proteomics and metabolomics as powerful tools for elucidation of biodegradation mechanisms.
Topics: Aerobiosis; Bacteria; Biodegradation, Environmental; Environmental Pollutants; Heterocyclic Compounds; Metabolic Networks and Pathways; Polycyclic Aromatic Hydrocarbons; Proteomics
PubMed: 19440284
DOI: 10.3390/ijerph6010278