TY - JOUR
T1 - Initial stages of calcium uptake and mineral deposition in sea urchin embryos
AU - Vidavsky, Netta
AU - Addadi, Sefi
AU - Mahamid, Julia
AU - Shimoni, Eyal
AU - Ben-Ezra, David
AU - Shpigel, Muki
AU - Weiner, Steve
AU - Addadi, Lia
N1 - German Research Foundation; Department of Energy award [DE-FG02-07ER15899]We thank Vladimir Kiss and Reinat Nevo for their help with confocal microscopy and Eugenia Klein, Elena Kartvelishvily, and the Irving and Cherna Moskowitz Center for Nano and Bio-Nano Imaging at the Weizmann Institute of Science for their help and guidance. The research was supported by a German Research Foundation grant within the framework of the Deutsch-Israelische Projektkooperation and a Department of Energy award (DE-FG02-07ER15899). L. A. is the incumbent of the Dorothy and Patrick Gorman Professorial Chair of Biological Ultrastructure, and S. W. is the incumbent of the Dr. Trude Burchardt Professorial Chair of Structural Biology.
PY - 2014/1/16
Y1 - 2014/1/16
N2 - Sea urchin larvae have an endoskeleton consisting of two calcitic spicules. We reconstructed various stages of the formation pathway of calcium carbonate from calcium ions in sea water to mineral deposition and integration into the forming spicules. Monitoring calcium uptake with the fluorescent dye calcein shows that calcium ions first penetrate the embryo and later are deposited intracellularly. Surprisingly, calcium carbonate deposits are distributed widely all over the embryo, including in the primary mesenchyme cells and in the surface epithelial cells. Using cryo- SEM, we show that the intracellular calcium carbonate deposits are contained in vesicles of diameter 0.5-1.5 μm. Using the newly developed airSEM, which allows direct correlation between fluorescence and energy dispersive spectroscopy, we confirmed the presence of solid calcium carbonate in the vesicles. This mineral phase appears as aggregates of 20-30-nm nanospheres, consistent with amorphous calcium carbonate. The aggregates finally are introduced into the spicule compartment, where they integrate into the growing spicule.
AB - Sea urchin larvae have an endoskeleton consisting of two calcitic spicules. We reconstructed various stages of the formation pathway of calcium carbonate from calcium ions in sea water to mineral deposition and integration into the forming spicules. Monitoring calcium uptake with the fluorescent dye calcein shows that calcium ions first penetrate the embryo and later are deposited intracellularly. Surprisingly, calcium carbonate deposits are distributed widely all over the embryo, including in the primary mesenchyme cells and in the surface epithelial cells. Using cryo- SEM, we show that the intracellular calcium carbonate deposits are contained in vesicles of diameter 0.5-1.5 μm. Using the newly developed airSEM, which allows direct correlation between fluorescence and energy dispersive spectroscopy, we confirmed the presence of solid calcium carbonate in the vesicles. This mineral phase appears as aggregates of 20-30-nm nanospheres, consistent with amorphous calcium carbonate. The aggregates finally are introduced into the spicule compartment, where they integrate into the growing spicule.
KW - Biomineralization
KW - Intracellular mineral deposition
KW - Mineralization pathway
KW - Sea urchin embryonic spicule
KW - Transient precursor mineral phase
UR - http://www.scopus.com/inward/record.url?scp=84891954871&partnerID=8YFLogxK
U2 - 10.1073/pnas.1312833110
DO - 10.1073/pnas.1312833110
M3 - Article
C2 - 24344263
SN - 0027-8424
VL - 111
SP - 39
EP - 44
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 1
ER -