On the formation and functions of high and very high magnesium calcites in the continuously growing teeth of the echinoderm Lytechinus variegatus: development of crystallinity and protein involvement.

نویسندگان

  • Arthur Veis
  • Stuart R Stock
  • Keith Alvares
  • Elizabeth Lux
چکیده

Sea urchin teeth grow continuously and develop a complex mineralized structure consisting of spatially separate but crystallographically aligned first stage calcitic elements of high Mg content (5-15 mol% mineral). These become cemented together by epitaxially oriented second stage very high Mg calcite (30-40 mol% mineral). In the tooth plumula, ingressing preodontoblasts create layered cellular syncytia. Mineral deposits develop within membrane-bound compartments between cellular syncytial layers. We seek to understand how this complex tooth architecture is developed, how individual crystalline calcitic elements become crystallographically aligned, and how their Mg composition is regulated. Synchrotron microbeam X-ray scattering was performed on live, freshly dissected teeth. We observed that the initial diffracting crystals lie within independent syncytial spaces in the plumula. These diffraction patterns match those of mature tooth calcite. Thus, the spatially separate crystallites grow with the same crystallographic orientation seen in the mature tooth. Mineral-related proteins from regions with differing Mg contents were isolated, sequenced, and characterized. A tooth cDNA library was constructed, and selected matrix-related proteins were cloned. Antibodies were prepared and used for immunolocaliztion. Matrix-related proteins are acidic, phosphorylated, and associated with the syncytial membranes. Time-of-flight secondary ion mass spectroscopy of various crystal elements shows unique amino acid, Mg, and Ca ion distributions. High and very high Mg calcites differ in Asp content. Matrix-related proteins are phosphorylated. Very high Mg calcite is associated with Asp-rich protein, and it is restricted to the second stage mineral. Thus, the composition at each part of the tooth is related to architecture and function.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

MINERAL PHASE MICROSTRUCTURE IN TEETH OF THE SHORT SPINED SEA URCHIN (Lytechinus variegatus) STUDIED WITH X-RAY PHASE CONTRAST IMAGING AND WITH ABSORPTION MICROTOMOGRAPHY, S.R. Stock, T. Dahl, J. Barss, A. Veiss, K. Fezzaa, W.K. Lee, pp. 133-138

X-ray absorption microtomography, a high resolution variant of medical “CT”, and synchrotron x-ray phase contrast imaging reveal the distribution of mineral within teeth of the sea urchin Lytechinus variegatus. Data from these imaging modalities on intact teeth are compared with histochemically stained thin sections observed with transmission optical microscopy. Because these teeth grow continu...

متن کامل

Changes in Wheat Starch Crystallinity During Staling of Flat Breads: Effects of Protein on Retrogradation

ABSTRACT: The crystallinity of wheat starch in two types of flat breads was studied using Differential Scanning Calorimetery. Three types of flours with different proteins of 9.4, 11.6 and 13.5% were prepared and two different types of flat breads with thicknesses of 2 and 3 millimeters were baked from each flour. The crystallization enthalpy (∆H), peak temperature (Tp) and onset point temperat...

متن کامل

Echinoderm Phosphorylated Matrix Proteins UTMP16 and UTMP19 Have Different Functions in Sea Urchin Tooth Mineralization*

Studies of mineralization of embryonic spicules and of the sea urchin genome have identified several putative mineralization-related proteins. These predicted proteins have not been isolated or confirmed in mature mineralized tissues. Mature Lytechinus variegatus teeth were demineralized with 0.6 N HCl after prior removal of non-mineralized constituents with 4.0 M guanidinium HCl. The HCl-extra...

متن کامل

Making a mouth: elucidating morphogenetic events of mouth development in the sea urchin Lytechinus variegatus

Deuterostomes are bilaterian animals in which the blastopore, the site of gastrulation, becomes the anus and the mouth develops secondarily. Deuterostome phyla include Chordata, such as vertebrates like ourselves, and Echinodermata, such as sea urchins. The extent of homology among deuterostome mouths is unknown. To address this question, this thesis compares three aspects of mouth morphogenesi...

متن کامل

Investigation on Mechanism of Cordierite Formation from Nano Silica-Magnesium chloride-Reactive Alumina

Cordierite ceramics are used as refractory materials and kiln furnaces tools due to their very low coefficient of thermal expansion, high corrosion resistance and excellent thermal shock resistance. The aim of the present work was to synthesis of cordierite with raw materials including nano silica, magnesium chloride and reactive alumina. The synthesis procedure is done at solid state. Mechanis...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • Cells, tissues, organs

دوره 194 2-4  شماره 

صفحات  -

تاریخ انتشار 2011