Search results for "gène"

Lipopolysaccharides and glucagon-like peptide 1 : from molecular mechanisms to pathophysiology

2016

Obesity and type 2 diabetes are metabolic diseases which have reached epidemic proportions worldwide. These metabolic disorders are related to a low grade inflammation whose molecular origin is still unknown. Previous studies have highlighted the involvement of the gut microbiota and especially components of the cell wall of Gram(-) bacteria: lipopolysaccharides (LPS). We have recently shown that LPS enhance glucagon-like peptide 1 (GLP-1) plasma levels, a hormone which is known to stimulate insulin secretion. Moreover there would be a link between the nutritional qualities of food and LPS plasma levels. Thus diet, LPS and GLP-1 may be closely related. The present work focuses on i) the mol…

Haro sur l'apéro, ou quels sont les pièges pour manger trop ?

2010

Détection hypothalamique de l’hyperglycémie : rôle de la dynamique mitochondriale dans la signalisation par les espèces actives de l’oxygène

2011

Allergies et intolérances alimentaires : Fiches pratiques sur les 14 allergènes majeurs

2016

International audience; Les allergies et les intolérances alimentaires représentent un enjeu majeur pour l’industrie agroalimentaire. Présenté sous forme de fiches pratiques, cet ouvrage a pour objectif d’apporter une vision claire et synthétique sur le sujet. Il présente notamment les 14 allergènes majeurs et détaille pour chacun d’eux : la nature et les causes de l’allergie ; les préparations courantes dans lesquelles on le trouve, ses rôles nutritif et technologique ; les moyens pour le remplacer, selon que l’on souhaite conserver le goût, les valeurs nutritives ou simplement l’apparence.Les questions d’hygiène et de la maîtrise du risque sont également abordées, et une démarche pratique…

Inactivation of PadR, the repressor of the phenolic acid stress response, by molecular interaction with Usp1, a universal stress protein from Lactoba…

2009

ABSTRACT The phenolic acid decarboxylase gene padA is involved in the phenolic acid stress response (PASR) in gram-positive bacteria. In Lactobacillus plantarum , the padR gene encodes the negative transcriptional regulator of padA and is cotranscribed with a downstream gene, usp1 , which encodes a putative universal stress protein (USP), Usp1, of unknown function. The usp1 gene is overexpressed during the PASR. However, the role and the mechanism of action of the USPs are unknown in gram-positive bacteria. Therefore, to gain insights into the role of USPs in the PASR; (i) a usp1 deletion mutant was constructed; (ii) the two genes padR and usp1 were coexpressed with padA under its own promo…

Single-cell RNA sequencing unveils the shared and the distinct cytotoxic hallmarks of human TCRVδ1 and TCRVδ2 γδ T lymphocytes

2019

γδ T lymphocytes represent ∼1% of human peripheral blood mononuclear cells and even more cells in most tissues of vertebrates. Although they have important anticancer functions, most current single-cell RNA sequencing (scRNA-seq) studies do not identify γδ T lymphocytes because their transcriptomes at the single-cell level are unknown. Here we show that high-resolution clustering of large scRNA-seq datasets and a combination of gene signatures allow the specific detection of human γδ T lymphocytes and identification of their T cell receptor (TCR)Vδ1 and TCRVδ2 subsets in large datasets from complex cell mixtures. In t -distributed stochastic neighbor embedding plots from blood and tumor sa…

Exploring the diversity of listeria monocytogenes biofilm architecture by high-throughput confocal laser scanning microscopy and the predominance of …

2015

ABSTRACT Listeria monocytogenes is involved in food-borne illness with a high mortality rate. The persistence of the pathogen along the food chain can be associated with its ability to form biofilms on inert surfaces. While most of the phenotypes associated with biofilms are related to their spatial organization, most published data comparing biofilm formation by L. monocytogenes isolates are based on the quantitative crystal violet assay, which does not give access to structural information. Using a high-throughput confocal-imaging approach, the aim of this work was to decipher the structural diversity of biofilms formed by 96 L. monocytogenes strains isolated from various environments. Pr…

Monounsaturated fatly acid metabolism and colon cancer cells proliferation : role of Stearoyl-CoA desaturase-1 and effect of conjugated linoleic acid…

2012

Cancer cells adapt their metabolism in response to signals from the microenvironment and proliferation. Thus, MonoUnsaturated Fatty Acid (MUFA) synthesis is increased in colon cancer cells, and associated with increased Stearoyl-CoA Desaturase (SCD) activity, the rate limiting enzyme of MUFA biosynthesis. Polyunsaturated Fatty Acid (PUFA), as isomers of conjugated linoleic acid (CLA), exert inhibitor activity on SCD-1 and have anti-cancer properties, but their mechanisms are not yet clear. In this context, the aim of this work was first to evaluate the role of SCD-1 in the proliferation of colon cancer cells (CCC) and to define the underlying mechanisms. In a second time, we provide new inf…

Characterization and role of nitric oxide production in Arabidopsis thaliana defense responses induced by oligogalacturonides

2011

Nitric oxide (NO) regulates a wide range of plant processes from development toenvironmental adaptation. In this study, NO production and its effects were investigated in aplant-pathogen context. The production of NO following Arabidopsis treatment witholigogalacturonides (OGs), an endogenous elicitor of plant defense, was assessed using the NOsensitive probe 4, 5-diamino fluorescein diacetate. Pharmacological and genetic approaches wereused to analyze NO enzymatic sources and its role in the Arabidopsis thaliana /Botrytis cinereainteraction. We showed that NO production involves both a L-arginine- and a nitrate reductase(NR)-pathways. OGs-induced NO production was Ca2+-dependent and modula…

Study of biogenic amines metabolism in wine lactic acid bacteria

2011

Biogenic amines are indesirable compounds found in fermented products like wine. Lactic acid bacteria from wine, including Oenococcus oeni, the main actor of malolactic fermentation, are able to produce these molecules from nitrogenous precursors. In order to limited biogenic amines accumulation, it is necessary to understand the role of this production by strains responsible for the synthesis of these metabolites in food. That is why the European BiamFood project was put in place. Along my thesis, molecular tools were developed in order to mutate O. oeni genes (encoding decarboxylases), and to express genes of interest. Genetic clusters hdc from L. higardii and odc from O. oeni, responsibl…