Search results for "Biomineralization"
showing 10 items of 131 documents
Molecular Biomineralization: Toward an Understanding of the Biogenic Origin of Polymetallic Nodules, Seamount Crusts, and Hydrothermal Vents
2011
Polymetallic nodules and crusts, hydrothermal vents from the Deep Sea are economically interesting, since they contain alloying components, e.g., manganese or cobalt, that are used in the production of special steels; in addition, they contain rare metals applied for plasma screens, for magnets in hard disks, or in hybrid car motors. While hydrothermal vents can regenerate in weeks, polymetallic nodules and seamount crusts grow slowly. Even though the geochemical basis for the growth of the nodules and crusts has been well studied, the contribution of microorganisms to the formation of these minerals remained obscure. Recent HR-SEM (high-resolution scanning electron microscopy) analyses of …
Mollusc and brachiopod skeletal hard parts: Intricate archives of their marine environment
2015
The biogenic carbonate hard parts of fossil bivalves, cephalopods and brachiopods are among the most widely exploited marine archives of Phanerozoic environmental and climate dynamics research. The advent of novel analytical tools has led many workers to explore non-traditional geochemical and petrographic proxies, and work performed in neighbouring disciplines sheds light on the complex biomineralization strategies applied by these organisms. These considerations form a strong motivation to review the potential and problems related to the compilation and interpretation of proxy data from bivalve, cephalopod and brachiopod hard parts from the viewpoint of the sedimentologist and palaeoceano…
Templated Crystallisation of Calcium and Strontium Carbonates on Centred Rectangular Self-Assembled Monolayer Substrates
1998
SrCO3crystals display patterns of templating when grown on tailored self-assembled monolayers (right). As SrCO3 is isostructural with aragonite, comparison of the crystallisation of SrCO3 in the aragonite/strontianite modification with the crystallisation of CaCO3 in all three modifications might yield some insights into which factors are important for crystal growth.
Trapping Amorphous Intermediates of Carbonates – A Combined Total Scattering and NMR Study
2018
Crystallization via metastable phases plays an important role in chemical manufacturing, biomineralization, and protein crystallization, but the kinetic pathways leading from metastable phases to the stable crystalline modifications are not well understood. In particular, the fast crystallization of amorphous intermediates makes a detailed characterization challenging. To circumvent this problem, we devised a system that allows trapping and stabilizing the amorphous intermediates of representative carbonates (calcium, strontium, barium, manganese, and cadmium). The long-term stabilization of these transient species enabled a detailed investigation of their composition, structure, and morpho…
Deep conservation of bivalve nacre proteins highlighted by shell matrix proteomics of the Unionoida Elliptio complanata and Villosa lienosa.
2016
The formation of the molluscan shell nacre is regulated to a large extent by a matrix of extracellular macromolecules that are secreted by the shell-forming tissue, the mantle. This so-called ‘calcifying matrix’ is a complex mixture of proteins, glycoproteins and polysaccharides that is assembled and occluded within the mineral phase during the calcification process. Better molecular-level characterization of the substances that regulate nacre formation is still required. Notable advances in expressed tag sequencing of freshwater mussels, such as Elliptio complanata and Villosa lienosa , provide a pre-requisite to further characterize bivalve nacre proteins by a proteomic approach. In this…
Bio-vaterite formation by glycoproteins from freshwater pearls
2010
Abstract A 48 kDa acidic and putative calcium-binding glycoprotein was isolated from pearls of the freshwater mussel Hyriopsis cumingii . This protein was compared with a related 46 kDa polypeptide, obtained from the nacreous shell of the same species. Separation by two-dimensional gel electrophoresis revealed that the difference in molecular weight is due to the higher extent of glycosylation of the 48 kDa protein existing in pearls. Evidence is presented that the sugar moieties of the protein contribute to crystal growth, starting with the nucleation step. In in vitro precipitation experiments, the 48 kDa glycoprotein of pearls directed the formation of round-shaped vaterite crystals whil…
The shell matrix and microstructure of the Ram's Horn squid: Molecular and structural characterization.
2020
20 pages; International audience; Molluscs are one of the most diversified phyla among metazoans. Most of them produce an external calcified shell, resulting from the secretory activity of a specialized epithelium of the calcifying mantle. This biomineralization process is controlled by a set of extracellular macromolecules, the organic matrix. In spite of several studies, these components are mainly known for bivalves and gastropods. In the present study, we investigated the physical and biochemical properties of the internal planispiral shell of the Ram's Horn squid Spirula spirula. Scanning Electron Microscope investigations of the shell reveal a complex microstructural organization. The…
Characterization of molecular processes involved in the pearl formation in Pinctada margaritifera for the sustainable development of pearl farming in…
2011
11 pages; International audience
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…
Nautilin-63, a novel acidic glycoprotein from the shell nacre of Nautilus macromphalus
2011
In molluscs, and more generally in metazoan organisms, the production of a calcified skeleton is a complex molecular process that is regulated by the secretion of an extracellular organic matrix. This matrix constitutes a cohesive and functional macromolecular assemblage, containing mainly proteins, glycoproteins and polysaccharides that, together, control the biomineral formation. These macromolecules interact with the extruded precursor mineral ions, mainly calcium and bicarbonate, to form complex organo-mineral composites of well-defined microstructures. For several reasons related to its remarkable mechanical properties and to its high value in jewelry, nacre is by far the most studied …