Link between Intestinal CD36 Ligand Binding and Satiety Induced by a High Protein Diet in Mice

CD36 is a ubiquitous membrane glycoprotein that binds long-chain fatty acids. The presence of a functional CD36 is required for the induction of satiety by a lipid load and its role as a lipid receptor driving cellular signal has recently been demonstrated. Our project aimed to further explore the role of intestinal CD36 in the regulation of food intake. Duodenal infusions of vehicle or sulfo-N-succinimidyl-oleate (SSO) was performed prior to acute infusions of saline or Intralipid (IL) in mice. Infusion of minute quantities of IL induced a decrease in food intake (FI) compared to saline. Infusion of SSO had the same effect but no additive inhibitory effect was observed in presence of IL. No IL- or SSO-mediated satiety occurred in CD36-null mice. To determine whether the CD36-mediated hypophagic effect of lipids was maintained in animals fed a satietogen diet, mice were subjected to a High-Protein diet (HPD). Concomitantly with the satiety effect, a rise in intestinal CD36 gene expression was observed. No satiety effect occurred in CD36-null mice. HPD-fed WT mice showed a diminished FI compared to control mice, after saline duodenal infusion. But there was no further decrease after lipid infusion. The lipid-induced decrease in FI observed on control mice was accompanied by a rise in jejunal oleylethanolamide (OEA). Its level was higher in HPD-fed mice than in controls after saline infusion and was not changed by lipids. Overall, we demonstrate that lipid binding to intestinal CD36 is sufficient to produce a satiety effect. Moreover, it could participate in the satiety effect induced by HPD. Intestine can modulate FI by several mechanisms including an increase in OEA production and CD36 gene expression. Furthermore, intestine of mice adapted to HPD have a diminished capacity to modulate their food intake in response to dietary lipids

Extraction of pure components from overlapped signals in gas chromatography-mass spectrometry (GC-MS)

Gas chromatography-mass spectrometry (GC-MS) is a widely used analytical technique for the identification and quantification of trace chemicals in complex mixtures. When complex samples are analyzed by GC-MS it is common to observe co-elution of two or more components, resulting in an overlap of signal peaks observed in the total ion chromatogram. In such situations manual signal analysis is often the most reliable means for the extraction of pure component signals; however, a systematic manual analysis over a number of samples is both tedious and prone to error. In the past 30 years a number of computational approaches were proposed to assist in the process of the extraction of pure signals from co-eluting GC-MS components. This includes empirical methods, comparison with library spectra, eigenvalue analysis, regression and others. However, to date no approach has been recognized as best, nor accepted as standard. This situation hampers general GC-MS capabilities, and in particular has implications for the development of robust, high-throughput GC-MS analytical protocols required in metabolic profiling and biomarker discovery. Here we first discuss the nature of GC-MS data, and then review some of the approaches proposed for the extraction of pure signals from co-eluting components. We summarize and classify different approaches to this problem, and examine why so many approaches proposed in the past have failed to live up to their full promise. Finally, we give some thoughts on the future developments in this field, and suggest that the progress in general computing capabilities attained in the past two decades has opened new horizons for tackling this important problem

Construire un modèle pluridisciplinaire autour de la gestion des casiers Girardon aquatiques

International audienc

Dike fields connectivity and diversity: a complex functioning on the Rhone River

International audienc

Dike fields connectivity and diversity: a complex functioning on the Rhone River

International audienc

Biodiversité des Casiers Girardon : vers une hiérarchisation des gains et des risques liés à la reconnexion de ces anthroposystèmes au chenal principal

International audienc

Flood inputs in a Mediterranean coastal zone impacted by a large urban area: Dynamic and fate of trace metals

Trace elements and organic carbon inputs to the Mediterranean sea from an urbanized area (Marseille city) were studied and characterized during flood events. Inputs were brought to the sea by two small coastal rivers whose waters were mixed together and also with treated wastewaters (TWW) just before discharge. The monitoring of the rivers during flood events showed the high temporal dynamics of water flow, suspended particulate matter (SPM), organic carbon and trace metals concentrations, typical of small coastal Mediterranean rivers and requiring an appropriate sampling strategy. Dissolved/particulate partition coefficient (log Kd) in rivers during floods remained quasi-constant for a given trace element, but differed from one element to another according to their affinity toward particles. Because of high SPM concentrations, trace elements were mainly brought to the sea during floods as particles, despite a weaker affinity for particles when compared to baseflow conditions for all studied elements but Pb. If the contribution of TWW dominated the elements baseflow discharge to the coastal zone, rivers outweighed during floods. When discharged to the sea, most trace elements underwent partial desorption in the salinity gradient, especially at highest salinity. Laboratory desorption experiments results were consistent with field data and showed slower desorption kinetics than in baseflow conditions, suggesting that trace elements desorption rates from particles are slower than sedimentation rates. With regard to heavy particles, it results in a potential impact of the sediment on benthic organisms and a possible further desorption after sediment resuspension events. With regard to light particles, it results possible additional desorption during offshore transport

Biodiversité des Casiers Girardon : vers une hiérarchisation des gains et des risques liés à la reconnexion de ces anthroposystèmes au chenal principal

International audienc