Search results for "biomineralization"
showing 10 items of 131 documents
Phase selection of calcium carbonate through the chirality of adsorbed amino acids.
2007
Crystallization of the CaCO3 mineral in the presence of the protein ovalbumin
2004
Abstract The kinetics of CaCO3 mineralization was studied by SANS in a 0.1 M aqueous CaCl2 solution in the presence of the protein ovalbumin found in chicken eggs. As the scattering from the protein and the mineral was observed within different Q regimes the evolution of the protein and mineral could be followed independently. It is observed that ovalbumin denaturates during the first 3 h and leads to a strong enhancement of mineralization.
Primary Cell Culture of Fresh Water Hyriopsis cumingii Mantle/Pearl Sac Tissues and Its Effect on Calcium Carbonate Mineralization
2014
Primary cell cultures of the fresh water Hyriopsis cumingii mantle and pearl sac tissues were produced in this study, and the influence of the tissue, cells, and secreted protein on calcium carbonate crystal nucleation and growth was studied. The study contributes to a further understanding of the influence of organic matrices on CaCO3 crystal formation. This research started from the protein level to the tissue/cell level, which is crucial for understanding the inorganic deposition process. The new data also add relevant theoretical approaches to an overall understanding of biomineralization processes. In the experimental groups with mantle or pearl sac tissue, the growth patterns of arago…
Synthesis of calcium carbonate biological materials: how many proteins are needed?
2013
In Nature, calcium carbonate biomineralizations are the most abundant mineralized structures of biological origin. Because many exhibit remarkable characteristics, several attempts have been made to use them as substitution materials for bone reconstruction or as models for generating biomimetic composites that exhibit tailored properties. CaCO3biomineralizations contain small amounts of amalgamate of proteins and polysaccharides that are secreted during the calcification process. They contribute to control the morphology of the crystallites and to spatially organize them in well-defined microstructures. These macromolecules, collectively defined as the skeletal matrix, have been the focus …
Possible functions of biomineralization of some Textulariid (Foraminifera) species of the Nw Iberian Margin
2016
The main goal of this work is to analyze the elemental composition of the test’s wall of some species/specimens of Textulariids (sub-class Subclass Textulariia), collected in surface sediments of the NW Iberian Margin. The elemental analyses was based on the Energy Dispersive Spectroscopy (EDS) on the Scanning Electron Microscope (SEM; Hitachi, S4100) of Textularia deltoidea, Textularia agglutinans, Sahulia conica, Karrerotextularia flintii, Siphotextularia heterostoma, Karreriella bradyi, Spiroplectammina sagittula and Arenoparrella mexicana . The elelemetal cocnentrations of the species wall were compared with the mineralogical composition (X-Ray diffraction) of the sediments of the stati…
Evolution and biomineralization of pteropod shells
2021
12 pages; International audience; Shelled pteropods, known as sea butterflies, are a group of small gastropods that spend their entire lives swimming and drifting in the open ocean. They build thin shells of aragonite, a metastable polymorph of calcium carbonate. Pteropod shells have been shown to experience dissolution and reduced thickness with a decrease in pH and therefore represent valuable bioindicators to monitor the impacts of ocean acidification. Over the past decades, several studies have highlighted the striking diversity of shell microstructures in pteropods, with exceptional mechanical properties, but their evolution and future in acidified waters remains uncertain. Here, we re…
Compartmentalization of gypsum and halite associated with cyanobacteria in saline soil crusts
2016
The interface between biological and geochemical components in surface crust of a saline soil was investigated using X-Ray Diffraction (XRD), and variable pressure scanning electron microscopy (SEM) in combination with Energy Dispersive X-ray Spectrometry (EDS). Mineral compounds such as halite and gypsum were identified crystallized around filaments of cyanobacteria. A total of 92 genera were identified from the bacterial community based on 16S gene pyrosequencing analysis. The occurrence of the gypsum crystals, their shapes and compartmentalization suggested that they separated NaCl from the immediate microenvironment of the cyanobacteria, and that some cyanobacteria and communities of su…
Genesis of amorphous calcium carbonate containing alveolar plates in the ciliate Coleps hirtus (Ciliophora, Prostomatea).
2013
7 pages; International audience; In the protist world, the ciliate Coleps hirtus (phylum Ciliophora, class Prostomatea) synthesizes a peculiar biomineralized test made of alveolar plates, structures located within alveolar vesicles at the cell cortex. Alveolar plates are arranged by overlapping like an armor and they are thought to protect and/or stiffen the cell. Although their morphology is species-specific and of complex architecture, so far almost nothing is known about their genesis, their structure and their elemental and mineral composition. We investigated the genesis of new alveolar plates after cell division and examined cells and isolated alveolar plates by electron microscopy, e…
Temperature-induced microstructural changes in shells of laboratory-grown Arctica islandica (Bivalvia).
2021
Bivalve shells are increasingly used as archives for high-resolution paleoclimate analyses. However, there is still an urgent need for quantitative temperature proxies that work without knowledge of the water chemistry–as is required for δ18O-based paleothermometry–and can better withstand diagenetic overprint. Recently, microstructural properties have been identified as a potential candidate fulfilling these requirements. So far, only few different microstructure categories (nacreous, prismatic and crossed-lamellar) of some short-lived species have been studied in detail, and in all such studies, the size and/or shape of individual biomineral units was found to increase with water temperat…
Climate variation during the Holocene influenced the skeletal properties of Chamelea gallina shells in the North Adriatic Sea (Italy)
2021
Understanding how marine taxa will respond to near-future climate changes is one of the main challenges for management of coastal ecosystem services. Ecological studies that investigate relationships between the environment and shell properties of commercially important marine species are commonly restricted to latitudinal gradients or small-scale laboratory experiments. This paper aimed to explore the variations in shell features and growth of the edible bivalve Chamelea gallina from the Holocene sedimentary succession to present-day thanatocoenosis of the Po Plain-Adriatic Sea system (Italy). Comparing the Holocene sub-fossil record to modern thanatocoenoses allowed obtaining an insight o…