Sea urchin tooth mineralization: Calcite present early in the aboral plumula

Stuart R Stock*, Arthur Veis, Xianghui Xiao, Jonathan D. Almer, Jason R. Dorvee

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

12 Scopus citations

Abstract

In both vertebrate bone, containing carbonated hydroxyapatite as the mineral phase, and in invertebrate hard tissue comprised of calcium carbonate, a popular view is that the mineral phase develops from a long-lived amorphous precursor which later transforms into crystal form. Important questions linked to this popular view are: when and where is the crystallized material formed, and is amorphous solid added subsequently to the crystalline substrate? Sea urchin teeth, in which the earliest mineral forms within isolated compartments, in a time and position dependent manner, allow direct investigation of the timing of crystallization of the calcite primary plates. Living teeth of the sea urchin Lytechinus variegatus, in their native coelomic fluid, were examined by high-energy synchrotron X-ray diffraction. The diffraction data show that calcite is present in the most aboral portions of the plumula, representing the very earliest stages of mineralization, and that this calcite has the same crystal orientation as in the more mature adoral portions of the same tooth. Raman spectroscopy of the aboral plumula confirms the initial primary plate mineral material is calcite and does not detect amorphous calcium carbonate; in the more mature adoral incisal flange, it does detect a broader calcite peak, consistent with two or more magnesium compositions. We hypothesize that some portion of each syncytial membrane in the plumula provides the information for nucleation of identically oriented calcite crystals that subsequently develop to form the complex geometry of the single crystal sea urchin tooth.

Original languageEnglish (US)
Pages (from-to)280-289
Number of pages10
JournalJournal of Structural Biology
Volume180
Issue number2
DOIs
StatePublished - Nov 1 2012

Keywords

  • Calcite
  • MicroCT
  • Raman spectroscopy
  • Sea urchin
  • Synchrotron radiation
  • Tooth
  • X-ray diffraction

ASJC Scopus subject areas

  • Structural Biology

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