scholarly journals Roles of redox systems in apoptosis triggered by reactive oxygen species.

Ensho ◽  
2000 ◽  
Vol 20 (1) ◽  
pp. 39-44
Author(s):  
Junichi Fujii
Keyword(s):  
Reactive Oxygen Species ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Redox Systems

scholarly journals Cell type-specific differences in redox regulation and proliferation after low UVA doses

2018 ◽  
Author(s):  
Sylwia Ciesielska ◽  
Patryk Bil ◽  
Karolina Gajda ◽  
Aleksandra Poterala-Hejmo ◽  
Dorota Hudy ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Redox Regulation ◽  
Cellular Proliferation ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Cell Type ◽  
Redox Systems ◽  
Human Colon Cancer ◽  
Cellular Redox ◽  
Hct116 Cells

AbstractUltraviolet A (UVA) radiation is harmful for living organisms but in low doses may stimulate cell proliferation. Our aim was to examine the relationships between exposure to different low UVA doses, cellular proliferation, and changes in cellular reactive oxygen species levels. In human colon cancer (HCT116) and melanoma (Me45) cells exposed to UVA doses comparable to environmental, the highest doses (30-50 kJ/m2) reduced clonogenic potential but some lower doses (1 and 10 kJ/m2) induced proliferation. This effect was cell type and dose specific. In both cell lines the levels of reactive oxygen species and nitric oxide fluctuated with dynamics which were influenced differently by UVA; in Me45 cells decreased proliferation accompanied the changes in the dynamics of H2O2 while in HCT116 cells those of superoxide. Genes coding for proteins engaged in redox systems were expressed differently in each cell line; transcripts for thioredoxin, peroxiredoxin and glutathione peroxidase showed higher expression in HCT116 cells whereas those for glutathione transferases and copper chaperone were more abundant in Me45 cells. We conclude that these two cell types utilize different pathways for regulating their redox status. Many mechanisms engaged in maintaining cellular redox balance have been described. Here we show that the different cellular responses to a stimulus such as a specific dose of UVA may be consequences of the use of different redox control pathways. Assays of superoxide and hydrogen peroxide level changes after exposure to UVA may clarify mechanisms of cellular redox regulation and help in understanding responses to stressing factors.

scholarly journals Oxidoreductases and Reactive Oxygen Species in Conversion of Lignocellulosic Biomass

2018 ◽  
Vol 82 (4) ◽  
Author(s):  
Bastien Bissaro ◽  
Anikó Várnai ◽  
Åsmund K. Røhr ◽  
Vincent G. H. Eijsink
Keyword(s):  
Reactive Oxygen Species ◽  
Plant Cell Wall ◽  
Biomass Conversion ◽  
Hydrolytic Enzymes ◽  
Reactive Oxygen ◽  
Industrial Applications ◽  
Fine Tuning ◽  
Oxygen Species ◽  
Redox Systems ◽  
Polysaccharide Monooxygenases

SUMMARYBiomass constitutes an appealing alternative to fossil resources for the production of materials and energy. The abundance and attractiveness of vegetal biomass come along with challenges pertaining to the intricacy of its structure, evolved during billions of years to face and resist abiotic and biotic attacks. To achieve the daunting goal of plant cell wall decomposition, microorganisms have developed many (enzymatic) strategies, from which we seek inspiration to develop biotechnological processes. A major breakthrough in the field has been the discovery of enzymes today known as lytic polysaccharide monooxygenases (LPMOs), which, by catalyzing the oxidative cleavage of recalcitrant polysaccharides, allow canonical hydrolytic enzymes to depolymerize the biomass more efficiently. Very recently, it has been shown that LPMOs are not classical monooxygenases in that they can also use hydrogen peroxide (H2O2) as an oxidant. This discovery calls for a revision of our understanding of how lignocellulolytic enzymes are connected since H2O2is produced and used by several of them. The first part of this review is dedicated to the LPMO paradigm, describing knowns, unknowns, and uncertainties. We then present different lignocellulolytic redox systems, enzymatic or not, that depend on fluxes of reactive oxygen species (ROS). Based on an assessment of these putatively interconnected systems, we suggest that fine-tuning of H2O2levels and proximity between sites of H2O2production and consumption are important for fungal biomass conversion. In the last part of this review, we discuss how our evolving understanding of redox processes involved in biomass depolymerization may translate into industrial applications.

scholarly journals Reactive oxygen species and the control of vascular function

2009 ◽  
Vol 296 (3) ◽  
pp. H539-H549 ◽  
Author(s):  
Michael S. Wolin
Keyword(s):  
Reactive Oxygen Species ◽  
Hydrogen Peroxide ◽  
Vascular Function ◽  
Soluble Guanylate Cyclase ◽  
Pulmonary Arteries ◽  
Reactive Oxygen ◽  
Vascular Diseases ◽  
Oxygen Species ◽  
Redox Systems ◽  
Cellular Peroxide

This article summarizes perspectives on how reactive oxygen species (ROS) and redox signaling mechanisms participate in regulating vascular smooth muscle function that have resulted from our studies over the past 25 years in areas including oxygen sensing and the regulation of cGMP production by soluble guanylate cyclase (sGC) that were presented in the Robert M. Berne Distinguished Lectureship at the 2008 Experimental Biology Meeting. It considers mechanisms controlling the activity of sources of ROS including Nox oxidases and mitochondria by physiological stimuli, vascular diseases processes, and metabolic mechanisms linked to NAD(P)H redox and hypoxia. Metabolic interactions of individual ROS such as hydrogen peroxide with cellular peroxide metabolizing enzymes are viewed as some of the most sensitive ways of influencing cellular signaling systems. The control of cytosolic NADPH redox also seems to be a major contributor to bovine coronary arterial relaxation to hypoxia, where its oxidation functions to coordinate the lowering of intracellular calcium, whereas increased cytosolic NADPH generation in pulmonary arteries appears to maintain elevated Nox oxidase activity, and relaxation to hydrogen peroxide, which is attenuated by hypoxia. The sensitivity of sGC to nitric oxide seems to be regulated by thiol and heme redox systems controlled by cytosolic NADPH. Heme biosynthesis and metabolism are also important factors regulating the sGC system. The signaling pathways controlling oxidases and their colocalization with redox-regulated systems enables selective activation of numerous regulatory mechanisms influencing vascular function in physiological processes and the progression of aging-associated vascular diseases.

Mitochondria as a source of reactive oxygen species

2009 ◽  
pp. c3 ◽  
Author(s):  
Helena M. Cochemé ◽  
Michael P. Murphy
Keyword(s):  
Reactive Oxygen Species ◽  
Reactive Oxygen ◽  
Oxygen Species

Clinical aspects of reactive oxygen and nitrogen species

2004 ◽  
Vol 71 ◽  
pp. 121-133 ◽  
Author(s):  
Ascan Warnholtz ◽  
Maria Wendt ◽  
Michael August ◽  
Thomas Münzel
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Risk Factor ◽  
Endothelial Dysfunction ◽  
Vascular Tissue ◽  
Rapid Development ◽  
Reactive Oxygen ◽  
Clinical Aspects ◽  
No Production ◽  
Oxygen Species

Endothelial dysfunction in the setting of cardiovascular risk factors, such as hypercholesterolaemia, hypertension, diabetes mellitus and chronic smoking, as well as in the setting of heart failure, has been shown to be at least partly dependent on the production of reactive oxygen species in endothelial and/or smooth muscle cells and the adventitia, and the subsequent decrease in vascular bioavailability of NO. Superoxide-producing enzymes involved in increased oxidative stress within vascular tissue include NAD(P)H-oxidase, xanthine oxidase and endothelial nitric oxide synthase in an uncoupled state. Recent studies indicate that endothelial dysfunction of peripheral and coronary resistance and conductance vessels represents a strong and independent risk factor for future cardiovascular events. Ways to reduce endothelial dysfunction include risk-factor modification and treatment with substances that have been shown to reduce oxidative stress and, simultaneously, to stimulate endothelial NO production, such as inhibitors of angiotensin-converting enzyme or the statins. In contrast, in conditions where increased production of reactive oxygen species, such as superoxide, in vascular tissue is established, treatment with NO, e.g. via administration of nitroglycerin, results in a rapid development of endothelial dysfunction, which may worsen the prognosis in patients with established coronary artery disease.

Fas ligand expression in rat kupffer cells in response to lipopolysaccharide is mediated by reactive oxygen species

2001 ◽  
Vol 120 (5) ◽  
pp. A361-A361
Author(s):  
K UCHIKURA ◽  
T WADA ◽  
Z SUN ◽  
S HOSHINO ◽  
G BULKLEY ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Kupffer Cells ◽  
Fas Ligand ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Ligand Expression
Sign in / Sign up

Export Citation Format

Share Document