Search results for "OXIDATION"

Inhibited fatty acid β-oxidation impairs stress resistance ability in Nile tilapia (Oreochromis niloticus)

2017

Energy metabolism plays important roles in stress resistance and immunity in mammals, however, such functions have not been established in fish. In the present study, Nile tilapia (Oreochromis niloticus) was fed with mildronate, an inhibitor of mitochondrial fatty acid (FA) β-oxidation, for six weeks subsequently challenged with Aeromonas hydrophila and ammonia nitrogen exposure. Mildronate treatment reduced significantly l-carnitine concentration and mitochondrial FA β-oxidation efficiency, while it increased lipid accumulation in liver. The fish with inhibited hepatic FA catabolism had lower survival rate when exposed to Aeromonas hydrophila and ammonia nitrogen. Moreover, fish fed mildro…

Oxidative signature of cerebrospinal fluid from mild cognitive impairment and Alzheimer disease patients

2015

Abstract Background Several studies suggest that pathological changes in Alzheimer’s disease (AD) brain begin around 10–20 years before the onset of cognitive impairment. Biomarkers that can support early diagnosis and predict development of dementia would, therefore, be crucial for patient care and evaluation of drug efficacy. Although cerebrospinal fluid (CSF) levels of Aβ42, tau, and p-tau are well-established diagnostic biomarkers of AD, there is an urgent need to identify additional molecular alterations of neuronal function that can be evaluated at the systemic level. Objectives This study was focused on the analysis of oxidative stress-related modifications of the CSF proteome, from …

2017

Human neurodegenerative diseases are accompanied by accumulation of heavily oxidized and aggregated proteins. However, the exact molecular reason is not fully elucidated yet. Insufficient cellular protein quality control is thought to play an important role in accumulating covalently oxidized misfolded proteins. Pharmacologically active polyphenols and their derivatives exhibit potential for preventive and therapeutic purposes against protein aggregation during neurodegeneration. Although these compounds act on various biochemical pathways, their role in stabilizing the protein degradation machinery at different stages may be an attractive therapeutical strategy to halt the accumulation of …

αB-crystallin response to a pro-oxidant non-cytotoxic environment in murine cardiac cells: An "in vitro" and "in vivo" study.

2020

The αB-crystallin (HSPB5) protein is modulated in response to a wide variety of stressors generated by multiple physio-pathological conditions, sustained by reactive oxygen species (ROS) production. In cardiac muscle tissue, this protein regulates various cellular processes, such as protein degradation, apoptosis and the stabilization of cytoskeletal elements. In this work, we studied the role of HSPB5 expression, activation and localization in HL-1 murine cardiomyocytes exposed to pro-oxidant and non-cytotoxic H2O2 concentration, as well as in cardiac tissue isolated from mice following an acute, non-damaging endurance exercise. Our results demonstrated that HSPB5 is the most abundant HSP …

Free-energy studies reveal a possible mechanism for oxidation-dependent inhibition of MGL

2016

AbstractThe function of monoacylglycerol lipase (MGL), a key actor in the hydrolytic deactivation of the endocannabinoid 2-arachidonoyl-sn-glycerol (2AG), is tightly controlled by the cell’s redox state: oxidative signals such as hydrogen peroxide suppress MGL activity in a reversible manner through sulfenylation of the peroxidatic cysteines, C201 and C208. Here, using as a starting point the crystal structures of human MGL (hMGL), we present evidence from molecular dynamics and metadynamics simulations along with high-resolution mass spectrometry studies indicating that sulfenylation of C201 and C208 alters the conformational equilibrium of the membrane-associated lid domain of MGL to favo…

CntA oxygenase substrate profile comparison and oxygen dependency of TMA production in Providencia rettgeri.

2017

CntA oxygenase is a Rieske 2S-2Fe cluster-containing protein that has been previously described as able to produce trimethylamine (TMA) from carnitine, gamma-butyrobetaine, glycine betaine, and in one case, choline. TMA found in humans is exclusively of bacterial origin, and its metabolite, trimethylamine oxide (TMAO), has been associated with atherosclerosis and heart and renal failure. We isolated four different Rieske oxygenases and determined that there are no significant differences in their substrate panels. All three had high activity toward carnitine/gamma-butyrobetaine, medium activity toward glycine betaine, and very low activity toward choline. We tested the influence of low oxyg…

Interference of carbidopa and other catechols with reactions catalyzed by peroxidases

2018

Abstract Background A number of compounds, including ascorbic acid, catecholamines, flavonoids, p-diphenols and hydrazine derivatives have been reported to interfere with peroxidase-based medical diagnostic tests (Trinder reaction) but the mechanisms of these effects have not been fully elucidated. Methods Reactions of bovine myeloperoxidase with o-dianisidine, bovine lactoperoxidase with ABTS and horseradish peroxidase with 4-aminoantipyrine/phenol in the presence of carbidopa, an anti-Parkinsonian drug, and other catechols, including l -dopa, were monitored spectrophotometrically and by measuring hydrogen peroxide consumption. Results Chromophore formation in all three enzyme/substrate sy…

Reductive Stress: A New Concept in Alzheimer's Disease

2015

Reactive oxygen species play a physiological role in cell signaling and also a pathological role in diseases, when antioxidant defenses are overwhelmed causing oxidative stress. However, in this review we will focus on reductive stress that may be defined as a pathophysiological situation in which the cell becomes more reduced than in the normal, resting state. This may occur in hypoxia and also in several diseases in which a small but persistent generation of oxidants results in a hormetic overexpression of antioxidant enzymes that leads to a reduction in cell compartments. This is the case of Alzheimer's disease. Individuals at high risk of Alzheimer's (because they carry the ApoE4 allele…

Contribution of cholesterol and oxysterols to the pathophysiology of Parkinson's disease

2016

International audience; Neurodegenerative diseases are a major public health issue worldwide. Some countries, including France, have engaged in research into the causes of Parkinson's disease, Alzheimer's disease, and multiple sclerosis and the management of these patients. It should lead to a better understanding of the mechanisms leading to these diseases including the possible involvement of lipids in their pathogenesis. Parkinson's disease is a progressive neurodegenerative disorder characterized by the loss of dopaminergic neurons in the substantia nigra and the accumulation of α-synuclein (Lewy bodies). Several in vivo studies have shown a relationship between the lipid profile [chole…

The influence of oxygen and methane on nitrogen fixation in subarctic Sphagnum mosses

2018

Biological nitrogen fixation is an important source of bioavailable nitrogen in Sphagnum dominated peatlands. Sphagnum mosses harbor a diverse microbiome including nitrogen-fixing and methane (CH4) oxidizing bacteria. The inhibitory effect of oxygen on microbial nitrogen fixation is documented for many bacteria. However, the role of nitrogen-fixing methanotrophs in nitrogen supply to Sphagnum peat mosses is not well explored. Here, we investigated the role of both oxygen and methane on nitrogen fixation in subarctic Sphagnum peat mosses. Five species of Sphagnum mosses were sampled from two mesotrophic and three oligotrophic sites within the Lakkasuo peatland in Orivesi, central Finland. Mo…