Modulation of Type 5 Metabotropic Glutamate Receptor-Mediated Intracellular Calcium Mobilization by Regulator of G Protein Signaling 4 (RGS4) in Cultured Astrocytes.

Acting as GTPase activating proteins promoting the silencing of activated G-proteins, regulators of G protein signaling (RGSs) are generally considered negative modulators of cell signaling. In the CNS, the expression of RGS4 is altered in diverse pathologies and its upregulation was reported in astrocytes exposed to an inflammatory environment. In a model of cultured cortical astrocytes, we herein investigate the influence of RGS4 on intracellular calcium signaling mediated by type 5 metabotropic glutamate receptor (mGluR5), which is known to support the bidirectional communication between neurons and glial cells.

Do tidal fluctuations affect microplastics distribution and composition in coastal waters?

The hydro-meteorological conditions in marine environments are recognized to have a major impact on the transport and dispersion of microplastics (MP), although their precise effects remain poorly understood. This study investigates the effects of tidal fluctuations on MP abundance and composition in a megatidal coastal water. Waters samples were collected every ninety minutes over the course of two complete tidal cycles - one during spring tide and another during neap tide.

Microplastic inputs to the Mediterranean Sea during wet and dry seasons: The case of two Lebanese coastal outlets.

Few studies have highlighted the impact of urbanization and meteorological events on the quantity of microplastics (MPs) discharged into the sea through rivers. To evaluate this issue in the Mediterranean Basin, surface water samples were collected from two more or less urbanized Lebanese Rivers: the Nahr Ibrahim (S1) and the Nahr Antelias (S2), during dry and wet periods. A significant higher abundance of 14.

Vertical distribution of microplastics in a river water column using an innovative sampling method.

Due to limitations of sampling methods, subsurface water is usually a less well-investigated compartment of the water column when scientists assess microplastic contamination. In this study, microplastic (MP) contamination was assessed in a freshwater river both in surface and subsurface using an innovative sampling method. Microplastic contamination in the lower part of the water column, i.

An innovative approach for microplastic sampling in all surface water bodies using an aquatic drone.

The lack of one standardized method to evaluate microplastic pollution in different aquatic environments worldwide represent a gap to fill for the scientist's community. To help overcome this challenge, we adapted an aquatic drone, named Jellyfishbot®, to sample microplastics. The aquatic drone has been compared with the actual most used method for sampling MPs in surface waters: the Manta net.

Additives in polypropylene and polylactic acid food packaging: Chemical analysis and bioassays provide complementary tools for risk assessment.

Plastic food packaging represents 40 % of the plastic production worldwide and belongs to the 10 most commonly found items in aquatic environments. They are characterized by high additives contents with >4000 formulations available on the market. Thus they can release their constitutive chemicals (i.

Identification and quantification of plastic additives using pyrolysis-GC/MS: A review.

Analysis of organic plastic additives (OPAs) associated to plastic polymers is growing. The current review outlines the characteristics and the development of (multi-step) pyrolysis coupled with a gas chromatography mass spectrometer (Py-GC/MS) for the identification and semi-quantification of OPAs. Compared to traditional methods, Py-GC/MS offers advantages like suppressing extensive steps of preparation, limiting contamination due to solvents and the possibility to analyse minute particles.

Regulators of G protein signalling as pharmacological targets for the treatment of neuropathic pain.

Neuropathic pain, a specific type of chronic pain resulting from persistent nervous tissue lesions, is a debilitating condition that affects about 7% of the population. This condition remains particularly difficult to treat because of the poor understanding of its underlying mechanisms. Drugs currently used to alleviate this chronic pain syndrome are of limited benefit due to their lack of efficacy and the elevated risk of side effects, especially after a prolonged period of treatment.

Amyloid Precursor Protein (APP) Controls the Expression of the Transcriptional Activator Neuronal PAS Domain Protein 4 (NPAS4) and Synaptic GABA Release.

The amyloid precursor protein (APP) has been extensively studied as the precursor of the β-amyloid (Aβ) peptide, the major component of the senile plaques found in the brain of Alzheimer's disease (AD) patients. However, the function of APP per se in neuronal physiology remains to be fully elucidated. APP is expressed at high levels in the brain.

Occurrence and identification of microplastics in beach sediments from the Hauts-de-France region.

The present work was carried out to quantify microplastics (MP) from three sandy beaches along the Côte d'Opale coastline located in the Hauts-de-France region of northern France. Three different study sites located along the English Channel were investigated due to different levels of anthropopression and hydrodynamic conditions. Sediments were collected at three different tide lines: high tide line (HTL), middle of the intertidal zone (IZ), and low tide line (LTL), to investigate the effects of tide line on microplastic contamination.

Constitutive downregulation protein kinase C epsilon in hSOD1 astrocytes influences mGluR5 signaling and the regulation of glutamate uptake.

Accumulating evidence indicates that motor neuron degeneration in amyotrophic lateral sclerosis (ALS) is a non-cell-autonomous process and that impaired glutamate clearance by astrocytes, leading to excitotoxicity, could participate in progression of the disease. In astrocytes derived from an animal model of ALS (hSOD1 rats), activation of type 5 metabotropic glutamate receptor (mGluR5) fails to increase glutamate uptake, impeding a putative dynamic neuroprotective mechanism involving astrocytes. Using astrocyte cultures from hSOD1 rats, we have demonstrated that the typical Ca oscillations associated with mGluR5 activation were reduced, and that the majority of cells responded with a sustained elevation of intracellular Ca concentration.

Inflammation-associated regulation of RGS in astrocytes and putative implication in neuropathic pain.

Background: Regulators of G-protein signaling (RGS) are major physiological modulators of G-protein-coupled receptors (GPCR) signaling. Several GPCRs expressed in both neurons and astrocytes participate in the central control of pain processing, and the reduced efficacy of analgesics in neuropathic pain conditions may rely on alterations in RGS function. The expression and the regulation of RGS in astrocytes is poorly documented, and we herein hypothesized that neuroinflammation which is commonly observed in neuropathic pain could influence RGS expression in astrocytes.

PKC epsilon-dependent calcium oscillations associated with metabotropic glutamate receptor 5 prevent agonist-mediated receptor desensitization in astrocytes.

A critical role has been assigned to protein kinase C (PKC)ε in the control of intracellular calcium oscillations triggered upon activation of type 5 metabotropic glutamate receptor (mGluR5) in cultured astrocytes. Nevertheless, the physiological significance of this particular signalling profile in the response of astrocytes to glutamate remains largely unknown. Considering that kinases are frequently involved in the regulation of G protein-coupled receptors, we have examined a putative link between the nature of the calcium signals and the response regulation upon repeated exposures of astrocytes to the agonist (S)-3,5-dihydroxyphenylglycine.

Development of a qPCR Method for the Identification and Quantification of Two Closely Related Tuna Species, Bigeye Tuna (Thunnus obesus) and Yellowfin Tuna (Thunnus albacares), in Canned Tuna.

Bigeye tuna (Thunnus obesus) and yellowfin tuna (Thunnus albacares) are among the most widely used tuna species for canning purposes. Not only substitution but also mixing of tuna species is prohibited by the European regulation for canned tuna products. However, as juveniles of bigeye and yellowfin tunas are very difficult to distinguish, unintentional substitutions may occur during the canning process.

A new model of nerve injury in the rat reveals a role of Regulator of G protein Signaling 4 in tactile hypersensitivity.

Tactile hypersensitivity is one of the most debilitating symptoms of neuropathic pain syndromes. Clinical studies have suggested that its presence at early postoperative stages may predict chronic (neuropathic) pain after surgery. Currently available animal models are typically associated with consistent tactile hypersensitivity and are therefore limited to distinguish between mechanisms that underlie tactile hypersensitivity as opposed to mechanisms that protect against it.

Inhibition of the regulator of G protein signalling RGS4 in the spinal cord decreases neuropathic hyperalgesia and restores cannabinoid CB1 receptor signalling.

Background And Purpose: Regulators of G protein signalling (RGS) are major determinants of metabotropic receptor activity, reducing the lifespan of the GTP-bound state of G proteins. Because the reduced potency of analgesic agents in neuropathic pain may reflect alterations in RGS, we assessed the effects of CCG 63802, a specific RGS4 inhibitor, on pain hypersensitivity and signalling through cannabinoid receptors, in a model of neuropathic pain.

Experimental Approach: The partial sciatic nerve ligation (PSNL) model in male Sprague Dawley rats was used to measure paw withdrawal thresholds to mechanical (von Frey hairs) or thermal (Hargreaves method) stimuli, during and after intrathecal injection of CCG 63802.

Microbiota characterization of a Belgian protected designation of origin cheese, Herve cheese, using metagenomic analysis.

Herve cheese is a Belgian soft cheese with a washed rind, and is made from raw or pasteurized milk. The specific microbiota of this cheese has never previously been fully explored and the use of raw or pasteurized milk in addition to starters is assumed to affect the microbiota of the rind and the heart. The aim of the study was to analyze the bacterial microbiota of Herve cheese using classical microbiology and a metagenomic approach based on 16S ribosomal DNA pyrosequencing.

Identification and mRNA expression of pi-class glutathione S-transferase and selenium-dependent glutathione peroxidase in the gudgeon Gobio gobio exposed to PCB 77.

In aquatic environments some pollutants are present in water and sediments and organisms possess cellular detoxification systems to face up these xenobiotics. The gudgeon, Gobio gobio, is a freshwater benthopelagic fish that appears particularly adequate for an ecotoxicological assessment of rivers. The aim of this study was the identification of GST and GPx genes in this organism in order to develop new indicators of early exposure to xenobiotics in aquatic environments.

Metallothionein coding sequence identification and seasonal mRNA expression of detoxification genes in the bivalve Corbicula fluminea.

The aim of this study was to identify a metallothionein (MT) coding sequence from the freshwater bivalve Corbicula fluminea and to measure the seasonal transcriptional pattern of MT in parallel with several detoxification genes: superoxide dismutase (SOD), catalase (CAT), glutathione S-transferases (GST) and glutathione peroxidases (GPx), in the digestive gland and the gills of this bivalve during a 1-year period. We identified a C. fluminea MT complete cDNA sequence using RT-PCR and RACE-PCR.

Molecular cloning and expression study of pi-class glutathione S-transferase (pi-GST) and selenium-dependent glutathione peroxidase (Se-GPx) transcripts in the freshwater bivalve Dreissena polymorpha.

Glutathione S-transferases (GST) and glutathione peroxidases (GPx) are essential components of cellular detoxification systems. We identified GST and GPx transcripts in the freshwater bivalve Dreissena polymorpha, their full-length coding sequences were obtained by reverse-transcription PCR using degenerated primers followed by 5' and 3' RACE-PCR (rapid amplification of cDNA ends-PCR). The cDNA identified encoded proteins of 205 and 243 amino acids corresponding respectively to a pi-class GST and a selenium-dependent GPx.

Identification, sequencing and expression of selenium-dependent glutathione peroxidase transcript in the freshwater bivalve Unio tumidus exposed to Aroclor 1254.

Glutathione peroxidases (GPx) and glutathione S-transferases (GST) are essential enzymes of the cellular defense system. The aim of this work was the identification of GPx transcript in a freshwater bivalve, Unio tumidus, and the effects of Aroclor 1254 on GPx and pi-class GST (pi-GST) expression pattern. The GPx full-length coding sequence was obtained by reverse transcription PCR using degenerated primers followed by 5' and 3' rapid amplification of cDNA ends.

cDNA cloning and expression pattern of pi-class glutathione S-transferase in the freshwater bivalves Unio tumidus and Corbicula fluminea.

Glutathione S-transferases (GSTs) are enzymes involved in major detoxification reactions of xenobiotics in many organisms. The aim of this work was the identification of GST transcripts in the freshwater bivalves Unio tumidus and Corbicula fluminea. We used degenerated primers designed in the highly conserved regions of GST to amplify the corresponding mRNA.