Accession Number : ADA331408

Title :   Formation of Calcite Biocrystals; Structure and Formation of Matrix Glycoproteins.

Descriptive Note : Final rept. 1 Mar 93-28 Feb 97

Corporate Author : STATE UNIV OF NEW YORK AT STONY BROOK

Personal Author(s) : Lennarz, William J.

PDF Url : ADA331408

Report Date : 28 FEB 1997

Pagination or Media Count : 3

Abstract : The presence of proteins associated with the CaCO3-containing biocrystals found in a wide variety of marine organisms is well established. In these organisms, including the primitive skeleton (spicule) of the sea urchin embryo, the structural and functional role of these proteins either in the biomineralization process or in control of the structural features of the biocrystals is unclear. Recently, one of the matrix proteins of the sea urchin spicule, SM3O, has been shown to contain a carbohydrate chain (the 1223 epitope) that has been implicated in the process whereby Ca2+ is deposited as CaCO3. Because an understanding of the localization of this protein, as well as other proteins found within the spicule, is central to understanding their function, we undertook to develop methods to localize spicule matrix proteins in intact spicules, using immunogold techniques and scanning electron microscopy. Gold particles indicative of this matrix glycoprotein could not be detected on the surface of spicules that had been isolated from embryo homogenates and treated with alkaline hypochlorite to remove any associated membranous material. However, when isolated spicules were etched for 2 min with dilute acetic acid (10 mM) to expose more internal regions of the crystal, SM3O and perhaps other proteins bearing the 1223 carbohydrate epitope were detected in the calcite matrix. These results, indicating that these two antigens are widely distributed in the spicule, suggest that this technique should be applicable to any matrix protein for which antibodies are available.

Descriptors :   *GLYCOPROTEINS, *CALCITE, *MARINE BIOLOGY, *MICROORGANISMS, *SEA URCHINS, TISSUES(BIOLOGY), SCANNING ELECTRON MICROSCOPES, STRUCTURAL PROPERTIES, PROTEINS, REGIONS, ELECTRON MICROSCOPY, PARTICLES, INTERNAL, CHAINS, MEMBRANES, ANTIBODIES, GOLD, EMBRYOS, AQUATIC ORGANISMS, DILUTION, CARBOHYDRATES, ANTIGENS, ALKALINITY, HYPOCHLORITES, ACETIC ACID, MINERALIZATION.

Subject Categories : Biology
      Biological Oceanography

Distribution Statement : APPROVED FOR PUBLIC RELEASE