Study of the relationships between membrane lipid compositions and cell functions: Case of hemocytes of bivalves affected by disseminated neoplasia

• Main Author: Le Grand, Fabienne
• Other Authors: Chimie, Electrochimie Moléculaires et Chimie Analytique (CEMCA), Université de Brest (UBO)-Institut de Chimie - CNRS Chimie (INC-CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Brestois Santé Agro Matière (IBSAM), Université de Brest (UBO), Université de Bretagne occidentale - Brest, Yanic MARTY
• Format: Doctoral or Postdoctoral Thesis
• Language: French
• Published: HAL CCSD 2010
• Subjects: Composition lipidique membranaire; fonctions cellulaires; Cerastoderma edule; Mya arenaria; néoplasie disséminée; plasmalogènes; acides gras NMI; Membrane lipid composition; cell functions; disseminated neoplasia; plasmalogens; NMI fatty acids; [CHIM.ANAL]Chemical Sciences/Analytical chemistry; [SDV.BBM.BC]Life Sciences [q-bio]/Biochemistry; Molecular Biology/Biochemistry [q-bio.BM]; [SDV.BA]Life Sciences [q-bio]/Animal biology; Canada; Pacific; Crassostrea gigas; Pacific oyster; Prince Edward Island
• Online Access: https://theses.hal.science/tel-00684750; https://theses.hal.science/tel-00684750/document; https://theses.hal.science/tel-00684750/file/These_Fabienne_Le_Grand.pdf

The aim of the works presented in this PhD thesis was to evidence structure-functional characteristics of a precise cell type, bivalve hemocytes. Analytical tools such as high performance liquid chromatography (HPLC) and gas chromatography (GC) allowed an in-depth investigation of membrane lipid components. Detailed composition of phospholipid classes and subclasses and their respective specific fatty acid composition were evidenced. Moreover, use of flow cytometry allowed characterizing some hemocyte cell functions and ploidy. Membrane lipid composition of hemocytes was finely characterized in four bivalve species; the Pacific oyster Crassostrea gigas, the Manila clam, Ruditapes philippinarum, the edible cockle Cerastoderma edule and the soft-shell clam Mya arenaria. Among the main lipid particularities, a high content of plasmalogen enriched in non-methylene interrupted (NMI) fatty acids and in 20:1n-11 was evidenced for the first time in hemocytes. These fatty acids present the particularity to be biosynthesized de novo in marine bivalves. Hemocyte membranes were also found to be very rich in ceramide aminoethylphosphonate (CAEP) and in sterols. The second step consisted in the study of the modifications of membrane lipid composition and cell functions potentially induced by disseminated neoplasia, in order to emerge structuro-functional links at the membrane level. For this purpose, circulating cells originating from healthy animals and from animals affected by disseminated neoplasia were compared in cockle from Arcachon Bay and in soft-shell clam from Prince-Edward-Island (Canada). In the case of cockles, a highly lower proportion of plasmalogen-NMI FA molecular species was observed in neoplastic cell membranes. This observation was associated to a lower phagocytic activity and a subcellular origin of reactive oxygen species (ROS) different. In soft-shell clams, a lower proportion of plasmalogen phosphatidylserine-20:1n-11 molecular species was associated to a lower phagocytic activity in circulating cells ...