Search results for "récepteur"
showing 10 items of 45 documents
Human taste receptors : study of structure-function relationships
2019
Sweet, umami and bitter taste detectors are membrane receptors that belong to the family of G-protein coupled receptors (GPCRs). They are characterized by the existence of a hydrophobic transmembrane domain (TMD) and an activation mechanism that involves a heterotrimeric G protein.Human has 25 bitter taste receptors TAS2R. These receptors belong to class A GPCRs. Their architecture consists of a TMD structured in 7 -helix which form the orthosteric binding site of bitter molecules. The umami taste receptor is a heterodimer composed of the TAS1R1 and TAS1R3 subunits, while the TAS1R2 and TAS1R3 subunits form the sweet taste receptor. Each subunits belongs to the class C GPCRs and shares a c…
New determinants of olfactory habituation
2017
AbstractHabituation is a filter that optimizes the processing of information by our brain in all sensory modalities. It results in an unconscious reduced responsiveness to continuous or repetitive stimulation. In olfaction, the main question is whether habituation works the same way for any odorant or whether we habituate differently to each odorant? In particular, whether chemical, physical or perceptual cues can limit or increase habituation. To test this, the odour intensity of 32 odorants differing in physicochemical characteristics was rated by 58 participants continuously during 120s. Each odorant was delivered at a constant concentration. Results showed odorants differed significantl…
Effect of two xeno-hormones, genistein and vinclozolin on development and exocrines and endocrines functions of submandibular salivary glands of Wist…
2012
The salivary glands are mixed glands: saliva (exocrine product) is involved inmaintaining oral homeostasis whereas endocrine secretions (eg growth factors) have aphysiological role (gametogenesis, osteogenesis, hypertension ..). In mammals, they displaysexual dimorphism suggesting a possible susceptibility to xeno-hormones.This manuscript presents the action of genistein (phytoestrogen) and/or vinclozolin (antiandrogenic)on the submandibular gland (SM) rats when performing an early exposure via themother (pregnancy, lactation) or an exposure during the growth period (from weaning toadulthood). The SM glands, collected at immature and young adult ages, have been analyzedaccording histologica…
Effets de deux xénohormones, la génistéine et la vinclozoline, sur le développement et les fonctions exocrines et endocrines des glandes salivaires s…
2012
http://tel.archives-ouvertes.fr/tel-00935290
Postnatal odorant exposure induces peripheral olfactory plasticity at the cellular level
2014
Mammalian olfactory sensory neurons (OSNs) form the primary elements of the olfactory system. Inserted in the olfactory mucosa lining of the nasal cavity, they are exposed to the environment and their lifespan is brief. Several reports say that OSNs are regularly regenerated during the entire life and that odorant environment affects the olfactory epithelium. However, little is known about the impact of the odorant environment on OSNs at the cellular level and more precisely in the context of early postnatal olfactory exposure. Here we exposed MOR23-green fluorescent protein (GFP) and M71-GFP mice to lyral or acetophenone, ligands for MOR23 or M71, respectively. Daily postnatal exposure to …
Mécanismes de résistance à l'apoptose induite par TRAIL dans les cellules cancéreuses : restauration de la sensibiltié à TRAIL par la chimiothérapie …
2010
The TNF-family member TRAIL (TNF-related apoptosis inducing ligand) is a cytokine involved in immune anti-tumour surveillance. TRAIL is one of the most promising agents currently under investigation, as it exhibits efficient anti-cancer cytotoxicity with limited side effects on healthy cells. The problem in current cancer therapy is that some cancer cells are already resistant, or can become resistant to TRAIL-induced cell death. The aim of my thesis was to study the mechanisms of resistance to TRAIL, and to find a way to bypass it. First, we were interested in the TRAIL-R4 antagonistic receptor, which is known to bind TRAIL without inducing a death signal. We have demonstrated for the firs…
Identification et caractérisation du récepteur à la flagelline (VvFLS2) et recherche du récepteur aux chito-oligosaccharides chez la vigne
2014
Pattern-recognition receptors (PRRs) play a key role in plant immunity by assuring recognition of microbe-associated molecular patterns (MAMPs), signature of microbial presence. MAMP perception constitutes the first layer of pathogen detection and activates defense mechanisms that aim to block the intruder. This study brings an insight into how grapevine (Vitis vinifera) perceives two MAMPs: the flagellin-derived flg22 peptide and chitin, which are conserved motifs occurring over the whole bacterial and fungal classes, respectively. This study analyzed MAMP-triggered early signaling events, defense gene expression and also the efficiency of elicited defense against gray mold and downy milde…
Des récepteurs à l'odeur : l'olfaction au quotidien
2022
Une des particularités du système olfactif est sa capacité à détecter et discriminer une myriade de composés odorants, le plus souvent présents en mélanges à des concentrations très faibles. Cette détection chimique est fondée sur une reconnaissance stéréochimique d'un ensemble complexe de molécules très diverses par des récepteurs olfactifs (RO). Des études génétiques conduites chez les rongeurs dès le début des années 1990 ont permis de dénombrer et d’identifier les gènes codant les récepteurs olfactifs. Cette découverte majeure a valu à Linda Buck et Richard Axel d’obtenir le Prix Nobel de médecine et physiologie en 2004. Des études génétiques ont révélé ensuite chez l’être humain la pré…
Biochimie des récepteurs du goût sucré
2013
Étude biochimique des récepteurs aux goûts sucré et umami : Rôle des domaines N-terminaux et caractérisation d'un inhibiteur spécifique, la gurmarine
2011
The sweet taste receptor is a heterodimer composed of two subunits called T1R2 and T1R3 whereas the T1R1 and the T1R3 subunits form a heterodimeric receptor for umami taste (the savory taste of monosodium glutamate). Each subunit belongs to the class C of G protein-coupled receptors (GPCRs) and is constituted by a large extracellular Nterminal domain (NTD) linked to the transmembrane domain by a cysteine-rich region. The NTD is composed of two lobes separated by a cleft in which ligands bind. T1R1- and T1R2-NTDs are able to bind sweeteners and umami compounds respectively and undergo ligand-dependent conformational changes (Zhang et al., 2008 ; Nie et al., 2005). However, the relative contr…