Search results for "cyclic"
showing 10 items of 2439 documents
The evolution of nitric oxide signalling diverges between the animal and the green lineages
2019
AbstractNitric oxide (NO) is a ubiquitous signalling molecule with widespread distribution in prokaryotes and eukaryotes where it is involved in countless physiological processes. While the mechanisms governing nitric oxide (NO) synthesis and signalling are well established in animals, the situation is less clear in the green lineage. Recent investigations have shown that NO synthase, the major enzymatic source for NO in animals, is absent in land plants but present in a limited number of algae. The first detailed analysis highlighted that these new NO synthases are functional but display specific structural features and probably original catalytic activities. Completing this picture, analy…
Evidences of regional differences in chlorine perception by consumers: sensitivity differences or habituation?
2010
Résumé du poster présenté.; Chlorinous flavors are one of the leading cause of customers’ complaints and dissatisfaction with drinking water. To investigate potential regional differences in chlorine perception, sensory testing experiments were conducted in France and in Spain to assess consumers’ sensory sensitivity (chlorine flavor detection threshold) as well as their liking and acceptance for chlorinated solutions. The chlorine flavor detection threshold was found to vary depending on countries (0.17 mg/LCl2 in France and 0.56 mg/LCl2 in Spain). According to the relation found between chlorine practices and average flavor detection thresholds, it is likely that habituation may support o…
The noncovalent dimerization of a G-quadruplex/hemin DNAzyme improves its biocatalytic properties.
2020
While many protein enzymes exert their functions through multimerization, which improves both selectivity and activity, this has not yet been demonstrated for other naturally occurring catalysts. Here, we report a multimerization effect applied to catalytic DNAs (or DNAzymes) and demonstrate that the enzymatic efficiency of G-quadruplexes (GQs) in interaction with the hemin cofactor is remarkably enhanced by homodimerization. The resulting non-covalent dimeric GQ–DNAzyme system provides hemin with a structurally defined active site in which both the cofactor (hemin) and the oxidant (H2O2) are activated. This new biocatalytic system efficiently performs peroxidase- and peroxygenase-type biot…
Significant biogenesis of chlorinated aromatics by fungi in natural environments
1994
Common wood- and forest litter-degrading fungi produce chlorinated anisyl metabolites. These compounds, which are structurally related to xenobiotic chloroaromatics, occur at high concentrations of approximately 75 mg of chlorinated anisyl metabolites kg of wood-1 or litter-1 in the environment. The widespread ability among common fungi to produce large amounts of chlorinated aromatic compounds in the environment makes us conclude that these kinds of compounds can no longer be considered to originate mainly from anthropogenic sources.
Implication of 24-S-hydroxycholesterol in Muller glial cell's membrane dynamics in the rat.
2016
Implication of 24-S-hydroxycholesterol in Muller glial cell's membrane dynamics in the rat.. Association-for-Research-in-Vision-and-Ophthalmology (ARVO)
In vivo oxydation of [9-14C] cyclic fatty acids derived from linoleic acid in the rat
2006
International audience; Abstract - Heating oils and fats may lead to cyclization of polyunsaturated fatty acids, as for example linolenic acid. Cyclohexenyl and cyclopentenyl fatty acids are subsequently present in some edible oils and these are suspected to induce metabolic disorders. In a previous experiment using [1-14C] labeled molecules, we published that these cyclic fatty acids are beta oxidized to the same extent as linolenic acid, at least for the first cycle of beta oxidation. However, it is possible that the presence of a ring could alter the ability of the organism to fully oxidize the molecule. In order to test this hypothesis, we assessed the oxidative metabolism of cyclic fat…
Influence of phytosterols on the structural and dynamic properties of plant plasma membrane
2008
National audience; The complex mixture of sterols, namely phytosterols, found in the plasma membrane (PM) of plant cells is an intriguing characteristic. In the present work, we characterized the sterol composition of tobacco BY-2 cell PM, and we adapted a sterol manipulation method to this plant material. Methyl-b-cyclodextrin was found to induce a drastic reduction of the PM total free sterol content, with a low specificity for the different phytosterols, and without effect on steryl-conjugates. The consequences of phytosterols depletion were investigated by means of fluorescence spectroscopy and biochemical detergent resistant membrane (DRM) fraction purification methods. Data obtained w…
Evaluation of the environmental fate and ecotoxicological impact of the pesticide chlorpyrifos in soil for improvement of its environmental risk asse…
2016
EABIOMEUBINRA; Pesticides protect crops from various pests but can also harm nontarget organisms. To minimize risks for the environment and human health, a huge amount of studies are carried out and evaluated during the authorization process of each pesticide. However, the prediction of the environmental fate and ecotoxicological impact of a pesticide remains difficult. Several 100 formerly used pesticides are now banned because unexpected risks emerged decades after their authorization. Risk assessment documents of the organophosphate insecticide chlorpyrifos (CHL) particularly lack information about its degradation and potential transformation products in soil, and its impact on non-targe…
Experimental and theoretical studies on electropolymerization of polar amino acids on platinum electrode
2017
International audience; The anodic oxidation of polar amino acids (L-serine, L-threonine, L-asparagine, and L-glutamine) in aqueous electrolyte on smooth platinum electrode was carried out by cyclic voltammetry coupled to electrochemical quartz crystal microbalance (EQCM). pH (zwitterion, acidic and alkaline) effects on their electrochemical behavior were examined. The maximum current values are measured for zwitterion species. In addition, the current increases with increasing of concentration and scan rate, and decreases with increasing pH. The resulting passivation was studied by spectroscopic analysis such as attenuated total reflection FT infrared spectroscopy (ATR-FTIR), X-ray photoel…
Electrochemistry of Bis(pyridine)cobalt (Nitrophenyl)corroles in Nonaqueous Media
2018
International audience; A series of bis(pyridine)cobalt corroles with one or three nitrophenyl groups on the meso positions of the corrole macrocycle were synthesized and characterized as to their electrochemical and spectroscopic properties in dichloromethane, benzonitrile, and pyridine. The potentials for each electrode reaction were measured by cyclic voltammetry and the electron-transfer mechanisms evaluated by analysis of the electrochemical data combined with UV-visible spectra of the neutral, electroreduced, and electroxidized forms of the corroles. The proposed electronic configurations of the initial compounds and the prevailing redox reactions involving the electroactive central c…