Structure and composition of Unio pictorum shell: arguments for the diversity of the nacroprismatic arrangement in molluscs.

TitreStructure and composition of Unio pictorum shell: arguments for the diversity of the nacroprismatic arrangement in molluscs.
Type de publicationJournal Article
Year of Publication2018
AuteursDauphin, Y, Luquet, G, Salomé, M, Bellot-Gurlet, L, Cuif, JP
JournalJournal of Microscopy
Volume270
Ticket2
Pagination156-169
Date Published05/2018
Type of ArticleJournal article
Résumé

Mollusc shells are complex organomineral structures, the arrangement and composition depending on the species. Most studies are dedicated to shells composed of an aragonite nacreous and a calcite prismatic layer, so the nacreous prismatic model based on Pinctada and Atrina-Pinna. Here, we studied the micro- and nanostructure, the mineralogy and composition of a nacroprismatic bivalve species: Unio pictorum. The prismatic layer of Unio is aragonite, and the inner structure of the prismatic units strongly differs from those of the calcitic layers. The shape of the prisms varies depending on their growth stage. The first layers of nacre are similar to those of gastropods (columnar nacre), then evolve towards the typical bivalve arrangement (sheet nacre). Na, Sr, Mg, P and S are present in both prisms and nacre. The organic prismatic envelopes are rich in sulphur amino acids, whereas organic sulphate is present within the prisms and the nacreous tablets. P is present as phosphate, probably a mixture of organic and mineral complex. Chemical distribution maps confirm the absence of an organic membrane between the nacre and the prisms. The comparison of the structure, mineralogy and composition of Unio pictorum and different species show the diversity of nacroprismatic shells, and that these features are taxonomically dependent.

Catégorie HCERES
ACL - Articles dans des revues à comité de lecture
Publication coopération et recherche SUD
Non