Jean-Marc Lebel

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The North Cotentin area (Normandy, France) hosts several nuclear facilities among which the AREVA reprocessing plant of La Hague is responsible for controlled discharges of liquid radioactive wastes into the marine environment. The resulting increase in radioactivity is very small compared to natural radioactivity. However, concerns about environment(More)
Environmental pollutants such as heavy metals exert immunotoxic effects on aquatic organisms. The immune defence of molluscs is comprised of cell-mediated and humoral mechanisms, in which haemocytes play a key role. In this study, a model based on primary cultured haemocytes from the gastropod mollusc Haliotis tuberculata was established to investigate the(More)
Among metals, cadmium, a non-essential element, is an important pollutant that is released into aquatic environments. Due to its persistence and bioaccumulation, this metal has been shown to exert immunological effects on organisms. The objective of the present study was to investigate the in vitro effects of cadmium chloride using a haemocyte primary(More)
Brown (BT) and rainbow trout (RT) in freshwater (FW) were treated with ovine growth hormone (GH), GH + iopanoic acid (IOP), and GH + IOP plus triiodothyronine (T3) for RT only. After 1 week of treatment, trout were transferred to 30 o/oo SW and treatment continued. In FW, GH treatment increased significantly plasma T3 level (BT) and T3/T4 ratio (BT and RT)(More)
During the annual cycle, oysters are exposed to seasonal slow changes in temperature, but during emersion at low tide on sunny summer days, their internal temperature may rise rapidly, resulting in acute heat stress. We experimentally exposed oysters to a 1-h acute thermal stress and investigated the transcriptional expression level of some genes involved(More)
Heat-shock proteins are a multigene family of proteins whose expression is induced by a variety of stress factors. This work reports the cloning and sequencing of HSP70 and HSP90 cDNAs in the gastropod Haliotis tuberculata. The deduced amino acid sequences of both HSP70 and HSP90 from H. tuberculata shared a high degree of homology with their homologues in(More)
In invertebrates, members of the collagen family have been found in various phyla. Surprisingly, in mollusc, little is known about such molecules. In this study, we characterize the full-length abalone type IV collagen and we analysed its biological effects on human fibroblast in order to gain insights about this molecule in molluscs and particularly clues(More)
In mollusks, the shell mineralization process is controlled by an array of proteins, glycoproteins and polysaccharides that collectively constitute the shell matrix. In spite of numerous researches, the shell protein content of a limited number of model species has been investigated. This paper presents biochemical data on the common edible land snail Helix(More)
Hemocytes constitute the key element of innate immunity in bivalves, being responsible for secretion of antimicrobial peptides and release of zymogens from the prophenoloxidase system within the hemolymph compartment, reactive oxygen species production and phagocytosis. Hemocytes are found (and collected) as cells in suspension in circulating hemolymph.(More)
The immune system of cephalopods remains poorly understood. The aim of this study was to determine the specific activity of immune enzymes in epithelial barriers, circulatory and digestive systems of the common cuttlefish Sepia officinalis. Three enzyme groups with putative functions in immunity were investigated: phenoloxidases (POs), lysozymes and(More)