Chalky versus foliated: a discriminant immunogold labelling of shell microstructures in the edible oyster Crassostrea gigas

• Published in: Marine Biology
• Main Authors: Mouchi, Vincent, Lartaud, Franck, Guichard, Nathalie, Immel, Françoise, de Rafélis, Marc, Broussard, Cédric, Crowley, Quentin G., Marin, Frédéric
• Other Authors: School of Natural Sciences, Trinity College Dublin, Institut des Sciences de la Terre de Paris (iSTeP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Ecogéochimie des environnements benthiques (LECOB), Observatoire océanologique de Banyuls (OOB), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Biogéosciences UMR 6282 (BGS), Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS), Laboratoire SUBATECH Nantes (SUBATECH), Mines Nantes (Mines Nantes)-Université de Nantes (UN)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de biogenèse membranaire (LBM), Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS), Géosciences Environnement Toulouse (GET), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Centre National de la Recherche Scientifique (CNRS), Institut Cochin (IC UM3 (UMR 8104 / U1016)), Université Paris Descartes - Paris 5 (UPD5)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2016
• Subjects: [SDV.BA.ZI]Life Sciences [q-bio]/Animal biology/Invertebrate Zoology; [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; Crassostrea gigas
• Online Access: https://hal.sorbonne-universite.fr/hal-01400675; https://hal.sorbonne-universite.fr/hal-01400675/document; https://hal.sorbonne-universite.fr/hal-01400675/file/Mouchi_2016_Chalky_versus.pdf; https://doi.org/10.1007/s00227-016-3040-6

International audience Mollusc shells are organic–inorganic biocomposites, arranged in a limited number of superimposed calcified layers that generally exhibit very different organization of their crystallites. Because of their attractive mechanical and crystallographic properties, these shell layers have been the focus of several physical and biochemical characterizations. In particular, recent proteomic data obtained from individual layers suggest that their protein contents are different. However, the direct visual evidence that some macromolecular components are layer-specific is rather tenuous. This paper is based on a non-conventional immunogold labelling approach to localize proteins in the shell of the edible oyster Crassostrea gigas. The shell microstructure of this model organism is predominantly composed of foliated calcite, interspersed by discontinuous pockets of ‘chalky layers’, a porous microstructure typical of bivalves of the ostreid family. By developing a polyclonal antibody (in two rats) elicited against a proteinaceous shell fraction, we obtained differential staining of the two microstructures. We assert that our labelling is microstructure discriminant. The difference in labelling of the two shell microstructures suggests either that they are formed by a variation of the secretory repertoire of the shell-forming cells of the calcifying mantle epithelium or that the chalky layer may be formed via a completely different mechanism. Our results allow a first glimpse on the subtle regulatory mechanisms that drive the process of chalky and foliated layers deposition.