Search results for "calcium storage"
showing 3 items of 3 documents
Proteoglycan occurrence in gastrolith of the crayfish Cherax quadricarinatus (Malacostraca: Decapoda).
2012
14 pages; International audience; Biomineralized structures are hybrid composites formed and stabilized by the close interaction of the organic and the inorganic phases. Crayfish are good models for studying biomineralization because they develop, in a molting-mineralization cycle, semi-spherical mineralized structures referred to as gastroliths. The organic matrix of these structures consists of proteins, polysaccharides, and lipids. Chitin is the main polysaccharide and is concentrically arranged as fibrous chitin-protein lamellar structures. Although several proteins and low-molecular weight phosphorylated components have been reported to be involved in gastrolith mineralization, the occ…
Biomineralizations: insights and prospects from crustaceans.
2011
19 pages; International audience; For growing, crustaceans have to molt cyclically because of the presence of a rigid exoskeleton. Most of the crustaceans harden their cuticle not only by sclerotization, like all the arthropods, but also by calcification. All the physiology of crustaceans, including the calcification process, is then linked to molting cycles. This means for these animals to find regularly a source of calcium ions quickly available just after ecdysis. The sources of calcium used are diverse, ranging from the environment where the animals live to endogenous calcium deposits cyclically elaborated by some of them. As a result, crustaceans are submitted to an important and energ…
Comparative ultrastructure and carbohydrate composition of gastroliths from Astacidae, Cambaridae and Parastacidae freshwater crayfish (Crustacea, De…
2012
21 pages; International audience; Crustaceans have to cyclically replace their rigid exoskeleton in order to grow. Most of them harden this skeleton by a calcification process. Some decapods (land crabs, lobsters and crayfish) elaborate calcium storage structures as a reservoir of calcium ions in their stomach wall, as so-called gastroliths. For a better understanding of the cyclic elaboration of these calcium deposits, we studied the ultrastructure of gastroliths from freshwater crayfish by using a combination of microscopic and physical techniques. Because sugars are also molecules putatively involved in the elaboration process of these biomineralizations, we also determined their carbohy…