Study of the Architecture of Inorganic-Organic Matrix in the Ventral Segmental Concretion of Porcellius Chilensis Nicole
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1007-S12-21
Study of the Architecture of Inorganic-Organic Matrix in the Ventral Segmental Concretion of Porcellius chilensis Nicolet, 1849 (Crustacea, Isopoda) Ranjith Krishna Pai1,2, Andrónico Neira-Carrillo1, Maria Soledad Fernandez1, and José Luis Arias1 1 Center for Advanced Interdisciplinary Research in Materials (CIMAT), University of Chile, Santa Rosa 11735, La Pintana, Casilla 2 Correo 15, Santiago, 2-15, Chile 2 Present:Material Chemistry Research Group, Department of Physical Inorganic and Structural Chemistry, Stockholm University, Arrhenius Laboratory,SE-10691, Stockholm, Sweden
ABSTRACT Mineralized biological concretions have attracted increasing interest because of their outstanding properties. The mineralized concretion of terrestrial isopods is an excellent model for acellular natural composite material. Before the molt terrestrial isopods resorb calcium from the posterior cuticle and store it in concretion within the cranial (head) and caudal (tail) ventral segments. This paper present for the first time an analysis of ultrastructural changes occurring in the caudal ventral segmental (CaVS) concretion of a terrestrial isopod Porcellius chilensis during their formation and degradation. The CaVS concretion of the woodlice Porcellius chilensis was analyzed with respect to their content of inorganic material. It was found that the concretion consists of amorphous calcium carbonate (ACC), and amorphous calcium phosphate (ACP), besides small amounts of water and an organic matrix. The CaVS concretion consists of structurally distinct stratum due to inhomogeneous solubility of ACC within the organic matrix that consists of calcareous knob with reticules elements. The organic matrix plays a role in the structural organization of the concretion and in the stabilization of ACC, which is unstable in vitro. We present an analysis of the distribution of minerals, elements, and organic matrix with in the CaVS concretion by using SEM, XRD, IR and EDS. The decalcification experiments exactly imitated the natural demineralization of the CaVS concretion of the Porcellius chilensis and it is thought that an inhomogeneous solubility of ACC and ACP within the CaVS concretion probably caused by variations in the stabilizing properties of matrix components. INTRODUCTION Biomineralization is the utilization of inorganic minerals by biological systems [1]. Typical examples are bone, teeth, shells, spicules, and mineralized plant hulls. A constantly increasing number of investigations demonstrated the presence of amorphous calcium carbonate (ACC) in calcified tissues. ACC is found as a precursor of the crystalline phases [2] and is thought to play an important role in the initiation of biomineralization processes. In addition, ACC is used as a transient store for calcium in some biological systems [3-7]. Since ACC is about ten times more soluble than the crystalline phases [8], it is unstable in vitro [9-10]. In living organisms, however, it seems to be stabilized by components of the organic matrix. Crustaceans are inter
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