Nanoscale Visualization of Biomineral Formation in Coral Proto-Polyps

Tali Mass, Jeana L. Drake, John M. Heddleston, Paul G. Falkowski

Research output: Contribution to journalArticlepeer-review

Abstract

Calcium carbonate platforms produced by reef-building stony corals over geologic time are pervasive features around the world [1]; however, the mechanism by which these organisms produce the mineral is poorly understood (see review by [2]). It is generally assumed that stony corals precipitate calcium carbonate extracellularly as aragonite in a calcifying medium between the calicoblastic ectoderm and pre-existing skeleton, separated from the overlying seawater [2]. The calicoblastic ectoderm produces extracellular matrix (ECM) proteins, secreted to the calcifying medium [3–6], which appear to provide the nucleation, alteration, elongation, and inhibition mechanisms of the biomineral [7] and remain occluded and preserved in the skeleton [8–10]. Here we show in cell cultures of the stony coral Stylophora pistillata that calcium is concentrated in intracellular pockets that are subsequently exported from the cell where a nucleation process leads to the formation of extracellular aragonite crystals. Analysis of the growing crystals by lattice light-sheet microscopy suggests that the crystals elongate from the cells’ surfaces outward. Using coral cell cultures, Mass et al. show that the stony coral biomineralization mechanism begins with intracellularly concentrated calcium, which is exported for extracellular crystal nucleation and growth. Aragonite crystals elongate outward from an extracellular protein matrix into the culture medium.

Original languageEnglish
Pages (from-to)3191-3196.e3
JournalCurrent Biology
Volume27
Issue number20
DOIs
StatePublished - 23 Oct 2017

Bibliographical note

Funding Information:
We thank J. Yaiullo of the Long Island Aquarium and Exhibition Center for coral nubbins, J. Adkins and Y. Guan at the CalTech Microanalysis Center for comments and technical assistance, and M. Pierce and N. Tumer at the Rutgers SEBS Core Facility Imaging Center. Additional imaging data used in this publication were produced in collaboration with the Advanced Imaging Center, a facility jointly supported by the Gordon and Betty Moore Foundation and the Howard Hughes Medical Institute. We thank V. Starovoytov, A. Fu, and M. Stern for technical assistance; E. Sweid for code assistance; and the Thor lab at the two-photon facility. We also thank three anonymous reviewers for insightful comments. The authors acknowledge funding from the National Science Foundation (Award EF-1416785 ) to P.G.F. and T.M.; Israel Science Foundation (Grant 312/15 ) to T.M.; and Sigma Xi GIAR (Award 280801 ) to J.L.D.

Publisher Copyright:
© 2017 Elsevier Ltd

Keywords

  • NanoSIMS
  • Stylophora pistillata
  • acidic proteins
  • biomineralization
  • lattice light-sheet microscopy

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology (all)
  • Agricultural and Biological Sciences (all)

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