Search results: Found 24

Listing 1 - 10 of 24 << page
of 3
>>
Sort by
Thiol-based redox homeostasis and signalling

Authors: --- --- --- --- et al.
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889192847 Year: Pages: 235 DOI: 10.3389/978-2-88919-284-7 Language: English
Publisher: Frontiers Media SA
Subject: Botany --- Physiology --- Science (General)
Added to DOAB on : 2015-12-10 11:59:07
License:

Loading...
Export citation

Choose an application

Abstract

In contrast to the situation in heterotrophic organisms, plant genomes code for a significantly larger number of oxidoreductases such as thioredoxins (TRXs) and glutaredoxins (GRXs). These proteins provide a biochemical mechanism that allows the rapid and reversible activation or deactivation of protein functions in response to changing environmental conditions, as oxidative conditions caused by excessive photosynthesis. Indeed, owing to the fact that cysteines are sensitive to oxidation, TRXs and GRXs play an essential role in controlling the redox state of protein thiol groups. These redox-dependent post-translational modifications have proven to be critical for many cellular functions constituting regulatory, signalling or protective mechanisms. The articles contained in this Research Topic provide timely overviews and new insights into thiol-dependent redox regulation mechanisms with a focus on TRX- and GRX-based reduction systems in plants. The different contexts discussed take into account physiological, developmental and environmental conditions.

Redox Homeostasis Managers in Plants under Environmental Stresses

Authors: --- --- --- --- et al.
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889198788 Year: Pages: 208 DOI: 10.3389/978-2-88919-878-8 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Environmental Sciences
Added to DOAB on : 2016-01-19 14:05:46
License:

Loading...
Export citation

Choose an application

Abstract

The production of cellular oxidants such as reactive oxygen species (ROS) is an inevitable con-sequence of redox cascades of aerobic metabolism in plants. This milieu is further aggravated by a myriad of adverse environmental conditions that plants, owing to their sessile life-style, have to cope with during their life cycle. Adverse conditions prevent plants reaching their full genetic potential in terms of growth and productivity mainly as a result of accelerated ROS generation-accrued redox imbalances and halted cellular metabolism. In order to sustain ROS-accrued consequences, plants tend to manage a fine homeostasis between the generation and antioxidants-mediated metabolisms of ROS and its reaction products. Well-known for their involvement in the regulation of several non-stress-related processes, redox related components such as proteinaceous thiol members such as thioredoxin, glutaredoxin, and peroxiredoxin proteins, and key soluble redox-compounds namely ascorbate (AsA) and glutathione (GSH) are also listed as efficient managers of cellular redox homeostasis in plants. The management of the cellular redox homeostasis is also contributed by electron carriers and energy metabolism mediators such as non-phosphorylated (NAD+) and the phosphorylated (NADP+) coenzyme forms and their redox couples DHA/AsA, GSSG/GSH, NAD+/NADH and NADP+/NADPH. Moreover, intracellular concentrations of these cellular redox homeostasis managers in plant cells fluctuate with the external environments and mediate dynamic signaling in pant stress responses. This research topic aims to exemplify new information on how redox homeostasis managers are modulated by environmental cues and what potential strategies are useful for improving cellular concentrations of major redox homeostasis managers. Additionally, it also aims to pro-vide readers detailed updates on specific topics, and to highlight so far unexplored aspects in the current context.

Hemichannels; from the molecule to the function

Authors: ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889194674 Year: Pages: 122 DOI: 10.3389/978-2-88919-467-4 Language: English
Publisher: Frontiers Media SA
Subject: Physiology --- Science (General)
Added to DOAB on : 2016-03-10 08:14:32
License:

Loading...
Export citation

Choose an application

Abstract

Coordinated cell interactions are required to accomplish several complex and dynamic tasks observed in several tissues. Cell function may be coordinated by cell-to-cell communication through gap junctions channels (GJCs). These channels are formed by the serial docking of two hemichannels, which in turn are formed by six protein subunits called connexins (Cxs). It is well known that GJCs are involved in several functions, such as intercellular propagation of calcium waves, spread of electrotonic potentialsand spatial buffering of ions and metabolites. On the other hand, undocked hemichannels, which are not forming GJCs, can also serve other functions as “free hemichannels”. Currently, it is recognized that undocked hemichannels may have functional relevance in cell physiology allowing diffusional exchange of ions and small molecules between intra- and extra-cellular compartments. Additionally, another family of proteins calls pannexins (Panx) also forms functional hemichannels at the plasma membrane. Recently, Panxhemichannels have been involved in both pathological and physiological processes. Controlled hemichannel opening allows the release of small signaling molecules including ATP, glutamate, NAD+, adenosine, cyclic nucleotides, PGE2. They also allow uptake of relevant signaling molecules (e.g., cADPR) and metabolites (e.g., glucose). Additionally, a growing body of evidence shows that hemichannels are involved in important processes, such glucose detection in tanicytes, activation of the inflammasome, memory consolidation in the basolateral amygdala, potentiation of muscle contraction and release of nitric oxide from endothelial cells, among others. However, hemichannels can also play an important role in the homeostatic imbalance observed in diverse chronic diseases. In fact, massive and/or uncontrolled hemichannel opening induces or accelerates cell death in several pathological conditions including Charcot-Marie-Tooth disease, ischemia, oculodentodigital dysplasia, hydrotic ectodermic dysplasia, inflammatory responses, and deafness. Hemichannel-mediated cell death is due mainly to an entry of Ca+2. The latter activates proteases, nucleases and lipases, causing irreversible cell damage. An increasing amount of evidence demonstrates that blockade of uncontrolled hemichannel opening greatly reduces the cellular damage observed in several chronic diseases models. Therefore, Cx and Panx-hemichannels appear as promising drug targets for clinical treatment of human chronic diseases. Therefore, pharmacological tools are urgently needed to further elucidate hemichannels functions and to validate them as drug targets for the development of novel therapies for connexin-based diseases. Thus, understanding the role of Cx and Panx-hemichannels under physiological conditions and recognizing the molecular mechanisms controlling them, may provide us with a better picture of the hemichannels participation in some diseases and of the signals underlying their malfunctioning.

Mitochondria: Hubs of Cellular Signaling, Energetics and Redox Balance

Authors: ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889452392 Year: Pages: 228 DOI: 10.3389/978-2-88945-239-2 Language: English
Publisher: Frontiers Media SA
Subject: Physiology --- Science (General)
Added to DOAB on : 2017-10-13 14:57:01
License:

Loading...
Export citation

Choose an application

Abstract

Poised at the convergence of most catabolic and anabolic pathways, mitochondria are the center of heterotrophic aerobic life, representing a hub in the overall metabolic network of cells. The energetic functions performed by mitochondria face the unavoidable redox hurdle of handling huge amounts of oxygen while keeping its own as well as the cellular redox environment under control. Reactive oxygen species (ROS) are produced in the respiratory chain as a result of the energy supplying function of mitochondria. Originally considered an unavoidable by-product of oxidative phosphorylation, ROS have become crucial signaling molecules when their levels are kept within physiological range. This occurs when their production and scavenging are balanced within mitochondria and cells. Mitochondria-generated hydrogen peroxide can act as a signaling molecule within mitochondria or in the cytoplasm, affecting multiple networks that control, for example, cell cycle, stress response, cell migration and adhesion, energy metabolism, redox balance, cell contraction, and ion channels. However, under pathophysiological conditions, excessive ROS levels can happen due to either overproduction, overwhelming of antioxidant defenses, or both. Under oxidative stress, detrimental effects of ROS include oxidation of protein, lipids, and nucleic acids; mitochondrial depolarization and calcium overload; and cell-wide oscillations mediated by ROS-induced ROS release mechanisms. Mitochondrial dysfunction is central in the pathogenesis of numerous human maladies including cardiomyopathies and neurodegeneration. Diseases characterized by altered nutrient metabolism, such as diabetes and cancer, exhibit elevated ROS levels. These may contribute to pathogenesis by increasing DNA mutation, affecting regulatory signaling and transcription, and promoting inflammation. Under metabolic stress, several ionic channels present in the inner and outer mitochondrial membranes can have pro-life and -death effects. In the present E-book, based on the Frontiers Research Topic entitled: "Mitochondria: Hubs of cellular signaling, energetics and redox balance", we address one of the fundamental questions that the field of ROS biology faces today: how do mitochondria accomplish a reliable energy provision and at the same time keep ROS levels within physiological, non-harming, limits but crucial for cellular signaling function? Additionally, and within the perspective of mitochondria as signaling-energetic hubs in the extensive cellular metabolic network, we ask how can their collective dynamics scale from the subcellular to the cellular, tissue and organ levels to affect function in health and disease.

Proceedings of the 3rd International Conference on Genetics of Aging and Longevity

Authors: ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889199266 Year: Pages: 88 DOI: 10.3389/978-2-88919-926-6 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Genetics
Added to DOAB on : 2016-01-19 14:05:46
License:

Loading...
Export citation

Choose an application

Abstract

In this book, we present a collection of articles covering a wide range of current aging research and highlighting its prospects and future directions. These articles are based on or related to the topics of the 3rd International Conference «Genetics of aging and longevity». The Conference took place 6-10 April, 2014 in Sochi, the city located on the Black Sea coast near the Caucasian mountains, in Russia. Top gerontologists and geneticists from 31 countries around the world came together to discuss current problems in many areas related to the genetics of longevity and mechanisms of aging. We would like to thank those of them who contributed to this e-Book by sharing latest achievements, ideas and hypotheses. We hope that this e-Book will come to notice of scientists interested in the development of genetics of aging and longevity and in the search for life-beneficial environments and life-prolonging interventions.

ROS Regulation during Plant Abiotic Stress Responses

Authors: --- --- ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889450541 Year: Pages: 306 DOI: 10.3389/978-2-88945-054-1 Language: English
Publisher: Frontiers Media SA
Subject: Botany --- Science (General)
Added to DOAB on : 2017-07-06 13:27:36
License:

Loading...
Export citation

Choose an application

Abstract

Plants are continuously exposed to a wide range of environmental conditions, including cold, drought, salt, heat, which have major impact on plant growth and development. To survive, plants have evolved complex physiological and biochemical adaptations to cope with a variety of adverse environmental stresses. Among them, reactive oxygen species (ROS) are key regulators and play pivotal roles during plant stress responses, which are thought to function as early signals during plant abiotic stress responses. ROS were long regarded as unwanted and toxic by-products of physiological metabolism. However, ROS are now recognized as central players in the complex signaling network of cells. Therefore, a fine-tuning control between ROS production and scavenging pathways is essential to maintain non-toxic levels in planta under stressful conditions through enzymatic and non-enzymatic antioxidant defense systems. We focus on the roles of ROS during plant abiotic stress responses in this Research Topic. Plant responses to multiple abiotic stresses and effects of hormones and chemicals on plant stress responses have been carefully studies. Although functions of several stress responsive genes have been characterized and possible interactions between hormones and ROS are discussed, future researches are needed to functionally characterize ROS regulatory and signaling transduction pathways.Plants are continuously exposed to a wide range of environmental conditions, including cold, drought, salt, heat, which have major impact on plant growth and development. To survive, plants have evolved complex physiological and biochemical adaptations to cope with a variety of adverse environmental stresses. Among them, reactive oxygen species (ROS) are key regulators and play pivotal roles during plant stress responses, which are thought to function as early signals during plant abiotic stress responses. ROS were long regarded as unwanted and toxic by-products of physiological metabolism. However, ROS are now recognized as central players in the complex signaling network of cells. Therefore, a fine-tuning control between ROS production and scavenging pathways is essential to maintain non-toxic levels in planta under stressful conditions through enzymatic and non-enzymatic antioxidant defense systems. We focus on the roles of ROS during plant abiotic stress responses in this Research Topic. Plant responses to multiple abiotic stresses and effects of hormones and chemicals on plant stress responses have been carefully studies. Although functions of several stress responsive genes have been characterized and possible interactions between hormones and ROS are discussed, future researches are needed to functionally characterize ROS regulatory and signaling transduction pathways.

The Metabolic-Inflammatory Axis in Brain Aging and Neurodegeneration

Authors: --- --- ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889452538 Year: Pages: 161 DOI: 10.3389/978-2-88945-253-8 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Neurology
Added to DOAB on : 2018-02-27 16:16:44
License:

Loading...
Export citation

Choose an application

Abstract

Impairment of energy metabolism is a hallmark of brain aging and several neurodegenerative diseases, such as the Alzheimer’s disease (AD). Age- and disease-related hypometabolism is commonly associated with oxidative stress and they are both regarded as major contributors to the decline in synaptic plasticity and cognition. Neuroinflammatory changes, entailing microglial activation and elevated expression of inflammatory cytokines, also correlate with age-related cognitive decline. It is still under debate whether the mitochondrial dysfunction-induced metabolic deficits or the microglia activation-mediated neuroinflammation is the initiator of the cognitive changes in aging and AD. Nevertheless, multiple lines of evidence support the notion that mitochondrial dysfunction and chronic inflammation exacerbate each other, and these mechanistic diversities have cellular redox dysregulation as a common denominator. This research topic focuses on the role of a metabolic-inflammatory axis encompassing the bioenergetic activity, brain inflammatory responses and their redox regulation in healthy brain aging and neurodegenerative diseases. Dynamic interactions among these systems are reviewed in terms of their causative or in-tandem occurrence and how the systemic environment, –e.g., insulin resistance, diabetes, and systemic inflammation–, impacts on brain function.

Redox and Metabolic Circuits in Cancer

Authors: --- --- ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889456352 Year: Pages: 183 DOI: 10.3389/978-2-88945-635-2 Language: English
Publisher: Frontiers Media SA
Subject: Medicine (General) --- Oncology
Added to DOAB on : 2019-01-23 14:53:43
License:

Loading...
Export citation

Choose an application

Abstract

Living cells require a constant supply of energy for the orchestration of a variety of biological processes in fluctuating environmental conditions. In heterotrophic organisms, energy mainly derives from the oxidation of carbohydrates and lipids, whose chemical bonds breakdown allows electrons to generate ATP and to provide reducing equivalents needed to restore the antioxidant systems and prevent from damage induced by reactive oxygen and nitric oxide (NO)-derived species (ROS and RNS). Studies of the last two decades have highlighted that cancer cells reprogram the metabolic circuitries in order to sustain their high growth rate, invade other tissues, and escape death. Therefore, this broad metabolic reorganization is mandatory for neoplastic growth, allowing the generation of adequate amounts of ATP and metabolites, as well as the optimization of redox homeostasis in the changeable environmental conditions of the tumor mass. Among these, ROS, as well as NO and RNS, which are produced at high extent in the tumor microenvironment or intracellularly, have been demonstrated acting as positive modulators of cell growth and frequently associated with malignant phenotype. Metabolic changes are also emerging as primary drivers of neoplastic onset and growth, and alterations of mitochondrial metabolism and homeostasis are emerging as pivotal in driving tumorigenesis.Targeting the metabolic rewiring, as well as affecting the balance between production and scavenging of ROS and NO-derived species, which underpin cancer growth, opens the possibility of finding selective and effective anti-neoplastic approaches, and new compounds affecting metabolic and/or redox adaptation of cancer cells are emerging as promising chemotherapeutic tools.In this Research Topic we have elaborated on all these aspects and provided our contribution to this increasingly growing field of research with new results, opinions and general overviews about the extraordinary plasticity of cancer cells to change metabolism and redox homeostasis in order to overcome the adverse conditions and sustain their “individualistic” behavior under a teleonomic viewpoint.

Prozessverständnis einer Naturkatastrophe: eine geo- und hydrochemische Untersuchung der regionalen Arsen-Anreicherung im Grundwasser West-Bengalens (Indien)

Author:
Book Series: Karlsruher Mineralogische und Geochemische Hefte ISSN: 16182677 ISBN: 3937300872 Year: Volume: 29 Pages: VIII, 165 p. DOI: 10.5445/KSP/1000003650 Language: GERMAN
Publisher: KIT Scientific Publishing
Subject: Astronomy (General)
Added to DOAB on : 2019-07-30 20:01:58
License:

Loading...
Export citation

Choose an application

Abstract

Die vorliegende Arbeit untersucht die regionale As-Grundwasseranreicherung in einem 35 km2 Gebiet in Kaliachak I (West-Bengalen, Indien), in dem Anomalien mit As-angereichertem Grundwasser in unmittelbarer Nähe zu unbelasteten Gebieten auftreten. Ziel der Arbeit ist die Charakterisierung des hydrogeochemischen Umfeldes der hohen As-Konzentrationen im Grundwasser und die Bestimmung der mineralogischen Speziation und Verfügbarkeit von Arsen in den Sedimenten des Aquifers.

Thioredoxin and Glutaredoxin Systems

Authors: ---
ISBN: 9783038978367 / 9783038978374 Year: Pages: 280 DOI: 10.3390/books978-3-03897-837-4 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Science (General) --- Biology
Added to DOAB on : 2019-06-26 08:44:06
License:

Loading...
Export citation

Choose an application

Abstract

This Special Issue features recent data concerning thioredoxins and glutaredoxins from various biological systems, including bacteria, mammals, and plants. Four of the sixteen articles are review papers that deal with the regulation of development of the effect of hydrogen peroxide and the interactions between oxidants and reductants, the description of methionine sulfoxide reductases, detoxification enzymes that require thioredoxin or glutaredoxin, and the response of plants to cold stress, respectively. This is followed by eleven research articles that focus on a reductant of thioredoxin in bacteria, a thioredoxin reductase, and a variety of plant and bacterial thioredoxins, including the m, f, o, and h isoforms and their targets. Various parameters are studied, including genetic, structural, and physiological properties of these systems. The redox regulation of monodehydroascorbate reductase, aminolevulinic acid dehydratase, and cytosolic isocitrate dehydrogenase could have very important consequences in plant metabolism. Also, the properties of the mitochondrial o-type thioredoxins and their unexpected capacity to bind iron–sulfur center (ISC) structures open new developments concerning the redox mitochondrial function and possibly ISC assembly in mitochondria. The final paper discusses interesting biotechnological applications of thioredoxin for breadmaking.

Keywords

methionine --- methionine sulfoxide --- methionine sulfoxide reductase --- physiological function --- protein --- plant --- repair --- redox homeostasis --- signaling --- stress --- mitochondria --- thioredoxin --- iron–sulfur cluster --- redox regulation --- ALAD --- tetrapyrrole biosynthesis --- redox control --- thioredoxins --- posttranslational modification --- chlorophyll --- redox regulation --- thioredoxin --- ferredoxin-thioredoxin reductase --- chloroplast --- H2O2 --- redox signalling --- development --- regeneration --- adult stem cells --- metazoan --- cyanobacteria --- thioredoxin --- photosynthesis --- redox active site --- thioredoxin --- disulfide --- flavin --- NADPH --- X-ray crystallography --- SAXS --- methanoarchaea --- chilling stress --- cold temperature --- posttranslational modification --- regulation --- ROS --- thiol redox network --- thioredoxin --- thioredoxin --- Calvin-Benson cycle --- photosynthesis --- carbon fixation --- chloroplast --- macromolecular crystallography --- protein-protein recognition --- electrostatic surface --- Chlamydomonas reinhardtii --- thioredoxin --- glutaredoxin --- legume plant --- symbiosis --- redox homeostasis --- stress --- thioredoxin --- monodehydroascorbate reductase --- water stress --- protein oxidation --- antioxidants --- ascorbate --- glutathione --- wheat --- thioredoxin --- thioredoxin reductase --- baking --- redox --- dough rheology --- protein oxidation --- methionine oxidation --- methionine sulfoxide reductases --- oxidized protein repair --- ageing --- Chlamydomonas reinhardtii --- cysteine alkylation --- cysteine reactivity --- MALDI-TOF mass spectrometry --- thioredoxin --- X-ray crystallography --- Isocitrate dehydrogenase --- glutathionylation --- nitrosylation --- glutaredoxin --- Arabidopsis thaliana --- thioredoxins --- plastidial --- specificity --- function --- proteomic --- photosynthesis --- Calvin cycle --- n/a

Listing 1 - 10 of 24 << page
of 3
>>
Sort by
Narrow your search