Publications by authors named "Torreilles J"

After the identification of nitric oxide (NO) with the endothelium derived-relaxing factor, many signaling mechanisms involving NO were identified through experiments on Mammals. NO activates soluble guanylyl cyclase leading to the formation of cGMP, stimulates the ADP-ribosylation of GAPDH, altering the cell energy production and combines with superoxide, generating cytotoxic peroxynitrite. NO was then progressively established as a major messenger molecule in Mammals.

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After the discovery of the vasodilatory functions of nitric oxide (NO), many signaling mechanisms involving NO were identified through experiments on mammals. NO activates soluble guanylyl cyclase to induce the formation of cGMP, stimulates ADP-ribosylation of GAPDH to alter cell energy production, and combines with superoxide to generate peroxynitrite. It then became clear that NO was a major messenger molecule in mammals, involved in the regulation of blood vessel dilatation, immune function and neurotransmission in the brain and peripheral nervous system.

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Background: Peroxynitrite is increasingly proposed as a contributor to defence system in marine bivalve. It can be formed by combination of superoxide and nitric oxide, and can react with tyrosine residues of proteins giving rise to 3-nitrotyrosine.

Results: The present article describes a competitive ELISA for the measurement of 3-nitrotyrosine contents of plasma proteins from marine bivalves by means of a monoclonal anti 3-nitrotyrosine antibody mouse IgG.

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The phagocytic activity of Mytilus galloprovincialis hemocytes is thought to be associated with NADPH-oxidase activity of the plasma membrane, thus producing superoxide anions. Few studies, however, have been devoted to nitric oxide release by these haemocytes. We investigated NO generation in M.

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The phagocytic process is one of the most important elements of the self-defence system in mammals as well as in molluscs. In mammalian phagocytes, superoxide participates in the innate defence system by combining with nitric oxide to generate peroxynitrite, a strong oxidant that possesses highly cytotoxic properties against bacteria. To evidence a role of nitric oxide in the self-defence system of the marine bivalve Mytilus galloprovincialis similar to the role observed in the mammalian defence system, we measured the generation of superoxide and nitrite/nitrate (the stable end products of nitric oxide) upon in vitro stimulation of M.

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Inflammatory reaction is thought to be an important contributor to neuronal damage in neurodegenerative disorders such as Alzheimer's disease (AD), Parkinson's disease (PD), multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS) and the parkinsonism dementia complex of Guam. Among the toxic agents released in brain tissues by activated cells, we focus attention in this review on peroxynitrite, the product of the reaction between nitric oxide (NO) and superoxide. Peroxynitrite is a strong oxidizing and nitrating agent which can react with all classes of biomolecules.

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To maintain their body integrity when aggressed, living organisms use a series of genetic and metabolic events constituting the stress response. Experiments carried out on man and superior vertebrates have shown that the stress response can be considered as a general adaptative syndrome. It constitutes one of the key elements of the defense system and can schematically be decomposed as an immediate response related to the release of preformed or formed de novo cytotoxic cell mediators and a delayed response with genomic interactions and induced protein synthesis.

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Malondialdehyde assay is the most generally used test in the appreciation of the role of oxidative stress in disease. Malondialdehyde is one of several products formed during the radical induced decomposition of polyunsaturated fatty acids. Most often, malondialdehyde assay used its reactivity at high temperature and low pH, towards thiobarbituric acid.

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Fluorescence spectra of the supernatant of adherent haemocyte monolayers from Mytilus galloprovincialis, supplemented with homovanillic acid or with a tyrosyl peptide glycylglycyltyrosine (GGY), were recorded before and after stimulation by zymosan. The formation of fluorescent derivatives was observed to have spectral characteristics similar to those of fluorescent compounds generated by the exposure of homovanillic acid or GGY to a horseradish peroxidase/hydrogen peroxide system in vitro. Lucigenine-enhanced chemiluminescence (CLluc) of M.

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Sea bass (Dicentrarchus labrax) were exposed for 71 days to three different ammonia concentrations corresponding to 0, 15 and 25% of the lethal threshold concentration causing the death of half a fish population in 96 hours. The study of the respiratory burst from sea bass renal macrophages showed that the luminol dependent chemiluminescence (CL) emitted following stimulation with mezerein is higher when fishes were previously exposed to ammonia. Therefore, it seemed that chronically exposure of fishes to sublethal concentrations of ammonia primed their renal macrophages to secrete higher amounts of oxygen activated species during respiratory burst, even several days after the transfer of fishes into a standard environment.

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The main results published on the production of reactive oxygen intermediates by hemocytes and digestive glands of marine bivalves such as mussels, oysters or clams have been reviewed and discussed. Mussel and oyster hemocytes respond to appropriate stimuli with a burst of respiratory activity and the generation of reactive oxygen intermediates in a manner resembling the respiratory burst of mammalian phagocytes. However, interspecies differences in hemocytes-mediated antimicrobial defense mechanisms occur since clam hemocytes do not show any increase of reactive oxygen intermediate production upon similar stimulations.

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To assess the role of superoxide (O2-) and nitric oxide (NO) in ischaemic-reperfusion-induced acute renal failure, we investigated whether an activation of the L-arginine-NO pathway contributes to ischaemia-reperfusion-induced kidney membrane peroxidation by measurement of 4-hydroxynonenal (HNE) content in anaesthetized rats submitted to acute renal ischaemia. Following ischaemia-reperfusion injury, renal blood flow (RBF) was significantly reduced, while renal vascular resistance was significantly increased. Infusion of neither L-arginine nor D-arginine led to a recovery of RBF.

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Serotonin (5-hydroxytryptamine, 5-HT) significantly and dose-dependently suppressed the luminol-enhanced chemiluminescence (CL) signal generated by polymorphonuclear leukocytes (PMN) activated with phorbol myristate acetate (PMA), but did not modify either lucigenin-enhanced CL or the reduction of superoxide dismutase-inhibitable cytochrome c. Moreover, stimulation of PMNs previously incubated with 5-HT resulted in a threefold increase in 5-HT equivalents bound to the proteins of PMN. The addition of catalase or sodium azide substantially reduced this binding.

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We measured the amounts of tyrosine and 3-nitrotyrosine (NO2-tyrosine) in proteins of plasma and polymorphonuclear leukocytes (PMN) from human whole blood before and after activation with phorbol ester (PMA) or calcium ionophore (A 23187). In unstimulated blood, no significant nitration of tyrosine was detected into PMN proteins, but a NO2-tyrosine/tyrosine ratio of 0.7% was detected in plasma proteins.

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Tyrosyl free radicals generated by the peroxidase-catalyzed oxidation of peptide tyrosyl residues are known to yield the stable cross-linked product dityrosine. In the present report, horseradish peroxidase is used as a model of peroxidase to study oxidative modifications of non-protein cellular components. Tyrosyl free radicals promote, as many free radicals, the decay of β-phycoerythrin fluorescence emission, they oxidize NADH and ascorbic acid and initiate arachidonic acid peroxidation with formation of hydroperoxides and dienes.

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Studies of chemical mechanisms involved in the reactivity of natural or synthetic chimioluminescent compounds show that chimioluminescent phenomena result always from redox reactions associated with energy transfers and often with electron transfers. Therefore, analytical methods based on chimioluminescence are very well adapted to detect and evaluate the free radicals: reactive oxygen species, nitric oxide and non oxygenated radicals, which are generated in biological systems.

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The results of the present study revealed that peptides derived from bovine casein hydrolysates can promote peroxidase-dependent oxidation of human low-density lipoproteins (LDL). The reaction was independent of the free metal ions but required casein-derived peptides with tryosyl-residues, implying that the tyrosyl radical is a diffusible catalyst that conveys oxidizing potential from the active site of the heme enzyme to LDL lipids. This mechanism is independent of the peroxidase used to oxidize tyrosyl residues since myeloperoxidase and horseradish peroxidase mediate a similar LDL peroxidating process.

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Nitric oxide (NO) is a free radical produced enzymatically in biological systems from the guanidino group of L-arginine. Its large spectrum of biological effects is achieved through chemical interactions with different targets including oxygen (O2), superoxide (O2o-) and other oxygen reactive species (ROS), transition metals and thiols. Superoxide anions and other ROS have been reported to react with NO to produce peroxynitrite anions that can decompose to form nitrogen dioxide (NO2) and hydroxyl radial (OHo).

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[Does nitric oxide stress exist?].

C R Seances Soc Biol Fil

January 1996

Ten years ago, the term "oxidative stress" (sigma -O2) was created to define oxidative damage inflicted to the organism. This definition brings together processes involving reactive oxygen species production and action such as free radical production during univalent reduction of oxygen within mitochondria, activation of NADPH-dependent oxidase system on the membrane surface of neutrophils, flavoprotein-catalyzed redox cycling of xenobiotics and exposure to chemical and physical agents in the environment. Since the discovery of the nitric oxide biosynthetic pathway, the deleterious effects of uncontrolled nitric oxide generation are generally classified as oxidative stress.

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Superoxide (O2-) and nitric oxide (.NO) are free radicals which are known to react together leading to peroxynitrite anions that can decompose to form nitrogen dioxide (NO2) and hydroxyl radical (OH degrees). .

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The effects of peptides derived from bovine casein hydrolysates were evaluated on oxygen-free radical release, 5-hydroxyeicosatetraenoic acid (5-HETE), and leukotriene B4 (LTB4) production by human polymorphonuclear leukocytes (PMNs). PMNs were activated by N-formyl-methionyl-leucyl-phenylalanine, phorbol myristate acetate, calcium ionophore (A23187), or opsonized zymosan. Tyrosyl-prolyl-phenylalanyl-proline (fragment 60-63 from bovine beta-casein) inhibited oxygen-free radical production and 5-HETE production but had no effect on the production of LTB4 and LTB4 isomers.

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Interest in NO measurement strongly increased with the discovery that NO is endogenously produced by living tissues. This review describes the major techniques for quantification of NO and derivatives in biological models.

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Basic peroxidation in brains of normal 2 month old mice was compared to that in brains of 25 month old mice by measurement of 4-hydroxy-2-nonenal and protein carbonyl contents. No significant age-related differences in 4-hydroxy-2-nonenal were observed, showing that lipid peroxidation is not a determining factor in cerebral aging. However, protein carbonyls increased with age in brains, indicating accumulation of age-related cell constituent damage.

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[Met]-enkephalin or its precursor, pre-[Met]-enkephalin, were exposed to activated oxygen species produced by human phorbol myristate acetate (PMA)-stimulated polymorphonuclear leukocytes (PMNs) and then analyzed by high-pressure liquid chromatography (HPLC). The chromatograms recorded at the tyrosine maximum wavelength (lambda em 300 nm and lambda ex 280 nm) showed the formation of new peptides by oxidation of methionyl residue in position 5 and ortho, meta, or para hydroxylation of phenylalanyl residue in position 4. The chromatograms recorded at the dityrosine maximum wavelength (lambda em 400 nm and lambda ex 325 nm) showed the formation of new dimeric peptides which contained two [Met]-enkephalin-derivatives linked by a dityrosyl group.

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Evidence is given that tyrosyl-peptides are dimerised by polymorphonuclear leukocytes leading to a new family of compounds. The products formed are homo- and hetero-dimeric peptides with linkage between the tyrosyl residues. This corresponds to a dityrosine structure as determined by analytic and spectroscopic data.

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