@article {5683, title = {Raman investigation of the pigment families in recent and fossil brachiopod shells}, journal = {Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy}, volume = {208}, year = {2019}, month = {09/2018}, pages = {73-84}, abstract = {

Shells of the three subphyla of extant and extinct representatives of the phylum Brachiopoda display coloured patterns with diverse shapes and at different degrees. These colourations are readily visible in natural light but are best revealed under UV light for the fossils concerned. To identify these pigments, Raman spectroscopy has been used for the first time on brachiopod shells. The widespread identified pigments belong to the carotenoid family, best represented in all the animal kingdom, the second one concerns themelanin/melanin-like pigments and, surprisingly, additional molecules of the cytochrome family are revealed for the first time in one of the brachiopod shells studied. The putative functions of shell pigmentation, still under debate, are discussed.

}, keywords = {Fossils Pigments, Raman spectroscopy, Recent brachiopods, Shell patterns, UV light}, author = {Gaspard, D and Paris, C and Loubry, P and Gilles Luquet} } @article {5350, title = {Freshwater acidification: an example of an endangered crayfish species sensitive to pH}, journal = {Hydrobiologia}, volume = {813}, year = {2018}, pages = {41-50}, abstract = {

Carbon dioxide released in the atmosphere\ and dissolved in water leads to acidification. Relatively\ few studies have focused on fresh waters, where\ biocalcifying species are more readily impacted by\ changes in pH. Sensitivity to pH of an endangered\ calcium-demanding organism, the crayfish Austropotamobius\ pallipes, was investigated in the Pinail\ nature reserve, a natural system with 3000 permanent\ ponds, some inhabited by the crayfish and others not,\ originally due to human introduction. From the 14\ chemical parameters measured in this study, the main\ limiting factor preventing crayfish establishment\ appears to be water acidity (pH\ 6.8), which affects\ calcification, molting, growth and reproduction. We\ predict that 20\% of the Pinail populations will\ disappear by 2060 due to freshwater acidification\ with the present level of fossil fuel consumption.

}, issn = {Print ISSN 0018-8158 
Online ISSN 1573-5117}, author = {David Beaune and Yann Sellier and Gilles Luquet and Fr{\'e}d{\'e}ric Grandjean} } @article {5615, title = {Revisiting the Organic Template Model through the Microstructural Study of Shell Development in Pinctada margaritifera, the Polynesian Pearl Oyster}, journal = {Minerals}, volume = {8}, year = {2018}, month = {09/2018}, pages = {370}, abstract = {A top-down approach to the mineralized structures and developmental steps that can be separated in the shells of Pinctada margaritifera was carried out. Detailed characterizations show that each of the two major layers usually taken into account (the outer prismatic layer and the inner nacreous layer) is actually the result of a complex process during which the microstructural patterns were progressively established. From its early growing stages in the deeper part of the periostracal grove up to the formation of the most inner nacreous layers, this species provides a demonstrative case study illustrating the leading role of specifically secreted organic structures as determinants of the crystallographic properties of the shell-building units. Gathering data established at various observational scales ranging from morphology to the nanometer level, this study allows for a reexamination of the recent and current biomineralization models.}, keywords = {biocrystallization model, biomineralization, Mollusca, shell development}, doi = {https://doi.org/10.3390/min8090370}, author = {Jean-Pierre Cuif and Yannicke Dauphin and Gilles Luquet and Kadda Medjoubi and Andrea Somogyi and Alberto Perez-Huerta} } @article {4526, title = {First proteomic analyses of the dorsal and ventral parts of the Sepia officinalis cuttlebone.}, journal = {J Proteomics}, volume = {150}, year = {2017}, month = {2016 Aug 26}, pages = {63-73}, abstract = {

Protein compounds constituting mollusk shells are known for their major roles in the biomineralization processes. These last years, a great diversity of shell proteins have been described in bivalves and gastropods allowing a better understanding of the calcification control by organic compounds and given promising applications in biotechnology. Here, we analyzed for the first time the organic matrix of the aragonitic Sepia officinalis shell, with an emphasis on protein composition of two different structures: the dorsal shield and the chambered part. Our results highlight an organic matrix mainly composed of polysaccharide, glycoprotein and protein compounds as previously described in other mollusk shells, with quantitative and qualitative differences between the dorsal shield and the chamber part. Proteomic analysis resulted in identification of only a few protein compounds underlining the lack of reference databases for Sepiidae. However, most of them contain domains previously characterized in matrix proteins of aragonitic shell-builder mollusks, suggesting ancient and conserved mechanisms of the aragonite biomineralization processes within mollusks.

BIOLOGICAL SIGNIFICANCE: The cuttlefish{\textquoteright}s inner shell, better known under the name "cuttlebone", is a complex mineral structure unique in mollusks and involved in tissue support and buoyancy regulation. Although it combines useful properties as high compressive strength, high porosity and high permeability, knowledge about organic compounds involved in its building remains limited. Moreover, several cuttlebone organic matrix studies reported data very different from each other or from other mollusk shells. Thus, this study provides 1) an overview of the organization of the main mineral structures found in the S. officinalis shell, 2) a reliable baseline about its organic composition, and 3) a first descriptive proteomic approach of organic matrices found in the two main parts of this shell. These data will contribute to the general knowledge about mollusk biomineralization as well as in the identification of protein compounds involved in the Sepiidae shell calcification.

}, issn = {1876-7737}, doi = {10.1016/j.jprot.2016.08.015}, author = {Le Pabic, Charles and Marie, Arul and Marie, Benjamin and Percot, Aline and Laure Bonnaud-Ponticelli and Pascal Jean Lopez and Gilles Luquet} } @article {4246, title = {Calcium Deposits in the Crayfish, Cherax quadricarinatus: Microstructure Versus Elemental Distribution}, journal = {Microscopy and Microanalysis}, volume = {22}, year = {2016}, pages = {22-38}, type = {Journal Article}, author = {Gilles Luquet and Yannicke Dauphin and Aline Percot and Murielle Salom{\'e} and Andreas Ziegler and Maria S. Fernandez and Jos{\'e} L. Arias} } @article {4527, title = {High-resolution structural and elemental analyses of calcium storage structures synthesized by the noble crayfish Astacus astacus.}, journal = {J Struct Biol}, year = {2016}, month = {2016 Sep 6}, abstract = {

During premolt, crayfish develop deposits of calcium ions, called gastroliths, in their stomach wall. The stored calcium is used for the calcification of parts of the skeleton regularly renewed for allowing growth. Structural and molecular analyses of gastroliths have been primarily performed on three crayfish species, Orconectes virilis, Procambarus clarkii, and more recently, Cherax quadricarinatus. We have performed high-resolution analyses of gastroliths from the native noble crayfish, Astacus astacus, focusing on the microstructure, the mineralogical and elemental composition and distribution in a comparative perspective. Field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) observations showed a classical layered microstructure composed of 200-nm diameter granules aligned along fibers. These granules are themselves composed of agglomerated nanogranules of 50nm-mean diameters. Denser regions of bigger fused granules are also present. Micro-Raman spectroscopy show that if A. astacus gastroliths, similarly to the other analyzed gastroliths, are mainly composed of amorphous calcium carbonate (ACC), they are also rich in amorphous calcium phosphate (ACP). The presence of a carotenoid pigment is also observed in A. astacus gastrolith contrary to C. quadricarinatus. Energy-dispersive X-ray spectroscopy (EDX) analyses demonstrate the presence of minor elements such as Mg, Sr, Si and P. The distribution of this last element is particularly heterogeneous. X-ray absorption near edge structure spectroscopy (XANES) reveals an alternation of layers more or less rich in phosphorus evidenced in the mineral phase as well as in the organic matrix in different molecular forms. Putative functions of the different P-comprising molecules are discussed.

}, issn = {1095-8657}, doi = {10.1016/j.jsb.2016.09.001}, author = {Gilles Luquet and Salom{\'e}, Murielle and Ziegler, Andreas and Paris, C{\'e}line and Percot, Aline and Dauphin, Yannicke} } @article {3430, title = {The skeleton of the staghorn coral Acropora millepora: molecular and structural characterization.}, journal = {PLoS One}, volume = {9}, year = {2014}, month = {2014}, pages = {e97454}, abstract = {

The scleractinian coral Acropora millepora is one of the most studied species from the Great Barrier Reef. This species has been used to understand evolutionary, immune and developmental processes in cnidarians. It has also been subject of several ecological studies in order to elucidate reef responses to environmental changes such as temperature rise and ocean acidification (OA). In these contexts, several nucleic acid resources were made available. When combined to a recent proteomic analysis of the coral skeletal organic matrix (SOM), they enabled the identification of several skeletal matrix proteins, making A. millepora into an emerging model for biomineralization studies. Here we describe the skeletal microstructure of A. millepora skeleton, together with a functional and biochemical characterization of its occluded SOM that focuses on the protein and saccharidic moieties. The skeletal matrix proteins show a large range of isoelectric points, compositional patterns and signatures. Besides secreted proteins, there are a significant number of proteins with membrane attachment sites such as transmembrane domains and GPI anchors as well as proteins with integrin binding sites. These features show that the skeletal proteins must have strong adhesion properties in order to function in the calcifying space. Moreover this data suggest a molecular connection between the calcifying epithelium and the skeletal tissue during biocalcification. In terms of sugar moieties, the enrichment of the SOM in arabinose is striking, and the monosaccharide composition exhibits the same signature as that of mucus of acroporid corals. Finally, we observe that the interaction of the acetic acid soluble SOM on the morphology of in vitro grown CaCO3 crystals is very pronounced when compared with the calcifying matrices of some mollusks. In light of these results, we wish to commend Acropora millepora as a model for biocalcification studies in scleractinians, from molecular and structural viewpoints.

}, keywords = {Acetic Acid, Amination, Animals, Anthozoa, Bone and Bones, Calcium Carbonate, Crystallization, Gels, Monosaccharides, Proteins, Solubility, Spectroscopy, Fourier Transform Infrared, Spectrum Analysis, Raman}, issn = {1932-6203}, doi = {10.1371/journal.pone.0097454}, author = {Ramos-Silva, Paula and Kaandorp, Jaap and Herbst, Fr{\'e}d{\'e}ric and Plasseraud, Laurent and Alcaraz, G and Stern, Christine and Corneillat, Marion and Guichard, N and Durlet, Christophe and Gilles Luquet and Marin, F} }