Caractérisation et rôle fonctionnel d'une famille de peptides calciotropes (CT et CGRP) (nouvelles données chez un téléostéen et deux mollusques céphalopodes)

Afin de mieux comprendre leur histoire évolutive, nous avons recherché la présence de la CT, du CGRP et de leurs organes cibles, chez un téléostéen, Anguilla anguilla, et deux céphalopodes, Nautilus macromphalus et Sepia officinalis. Contrairement à l anguille, aucune molécule biologiquement apparentée à la CT n a été détectée chez les céphalopodes. La co-localisation du CGRP et de son récepteur dans le système nerveux central de l anguille et de la seiche, suggère que ce peptide pourrait jouer un rôle de neuromédiateur ou neurotransmetteur comme décrit chez les mammifères. L implication du CGRP dans les mécanismes de régulation ionique, de façon endocrine dans les branchies et autocrine/paracrine dans le système rénal, représenterait une fonction ancienne, partagée par les téléostéens et les céphalopodes. Il semble que le CGRP ait une origine ancestrale intervenue avant l émergence des deutérostomiens. La CT constituerait un peptide apparu plus tardivement au cours de l évolution.PARIS-BIUSJ-Thèses (751052125) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF

An “in vitro” study of the biomineralization process using primary cell culture from the abalone Haliotis tuberculata

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Use of a commercial protease and yeasts for obtaining CGRP like molecules from saithe protein

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The occurrence of CGRP like molecule in a siki ( Centroscymnus coelolepsis) hydrolysate of industrial origin

International audienceFish protein hydrolysates (FPH) may have potential as bioactive components in functional foods as nutraceuticals. This study focused on the identification of calcitonin gene-related peptide (CGRP) molecules in FPH. CGRP is a neuropeptide belonging to the calcitonin/CGRP family, and is known as potent arterial and venous vasodilator in humans. Hydrolysates of industrial origin were prepared from siki (/Centroscymnus coelolepsis/) heads and analyzed for the presence of CGRP-like molecules using specific radioimmunoassays and radioreceptorassays. The biological activity of the CGRP-related molecules was assessed by their ability to stimulate the adenylate cyclase activity in rat liver membranes. They were finally purified using gel exclusion chromatography and HPLC. These molecules presented a molecular weight around 1500-2500 Da and were obtained with a purification factor of 79. The incorporation of FPH with CGRP-like molecules in functional foods could lead to develop new useful products for health and nutrition markets

Purification of a functional competitive antagonist for calcitonin gene related peptide action from sardine hydrolysates

Calcitonin gene related peptide (CGRP) related molecules were purified from sardine hydrolysates prepared using 0.1% alcalase and two hours of hydrolysis. Gel exclusion chromatography and HPLC performed purification of these molecules. The purified molecules were characterised using specific CGRP radioimmunoassays and radioreceptoraasays. From 22 mg of crude extract, we obtained 14 μg of CGRP related molecules, the molecular weight determined by mass spectrophotometry was 6000 daltons. The biological activity of these molecules was analysed using the ability of CGRP to stimulate the adenylate cyclase activity in rat liver membranes. The purified molecules induced an inhibition of the CGRP stimulated adenylate cyclase activity, this effect was specific as no such effect was observed on the glucagon stimulated adenylate cyclase activity measured in the same rat liver membrane preparation. These results suggest that the purified molecules may act as antagonists for peptides that bind to CGRP receptors in rat liver membranes. These new antagonists may be of particular importance in various aspects of CGRP action in vertebrates

Peptides from fish and crustacean by-products hydrolysates stimulate cholecystokinin release in STC-1 cells

International audienceFish protein hydrolysates (FPH) are of significant interest, due to their potential application as a source of bioactive peptides in nutraceutical and pharmaceutical domains. Here, we investigated the action of FPH from blue whiting (Micromesistius poutassou) and brown shrimp (Penaeus aztecus) on cholecystokinin release from intestinal endocrine cells (STC-1). We demonstrated for the first time that FPH were able to highly stimulate CCK-releasing activity from STC-1 cells and that this stimulation was mainly due to peptide molecules. The partial purification of CCK-stimulating peptides showed that their apparent molecular weight ranged between 1000 and 1500 Da for fish and crustacean FPH, respectively. Finally, in an aim to industrially produce hydrolysates enriched in CCK-stimulating molecules, we tested the effects of membrane processes (ultrafiltration and nanofiltration) on active peptide enrichment

CGRP regulates the activity of mantle cells and hemocytes in abalone primary cell cultures (Haliotis tuberculata)

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