title: Mineral Formation in the Larval Zebrafish Tail Bone Occurs via an Acidic Disordered Calcium Phosphate Phase.
abstract: Both in vivo and ex vivo observations support the hypothesis that bone mineral formation proceeds via disordered precursor phases. The characteristics of the precursor phases are not well defined, but octacalcium phosphate-like, amorphous calcium phosphate-like, and HPO42--enriched phases were detected. Here we use in vivo Raman spectroscopy and high-resolution wide-angle X-ray diffraction (WAXD) to characterize and map at 2 μm resolution the mineral phases in the rapidly forming tail fin bones of living zebrafish larvae and zebrafish larvae immediately after sacrifice, respectively. Raman spectroscopy shows the presence of an acidic disordered calcium phosphate phase with additional characteristic features of HPO42-at the bone-cell interface. The complexity in the position and shape of the ν1PO4peak viewed by in vivo Raman spectroscopy emphasizes the heterogeneity of the mineral during bone formation. WAXD detects an additional isolated peak, appearing alone or together with the characteristic diffraction pattern of carbonated hydroxyapatite. This unidentified phase is located at the interface between the mature bone and the surrounding tissue, similar to the location at which the disordered phase was observed by Raman spectroscopy. The variable peak positions and profiles support the notion that this is an unstable disordered precursor phase, which conceivably crystallized during the X-ray diffraction measurement. Interestingly, this precursor phase is co-aligned with the c-axes of the mature bone crystals and thus is in intimate relation with the surrounding collagen matrix. We conclude that a major disordered precursor mineral phase containing HPO42-is part of the deposition pathway of the rapidly forming tail fin bones of the zebrafish.
authors.affiliation: Department of Structural Biology, Weizmann Institute of Science , Rehovot 76100, Israel.
authors.forename: Anat
authors.initials: A
authors.lastname: Akiva
authors.affiliation: Department of Structural Biology, Weizmann Institute of Science , Rehovot 76100, Israel.
authors.forename: Michael
authors.initials: M
authors.lastname: Kerschnitzki
authors.affiliation: Department of Chemical Research Support, Weizmann Institute of Science , Rehovot 76100, Israel.
authors.forename: Iddo
authors.initials: I
authors.lastname: Pinkas
authors.affiliation: Department of Biomaterials, Max Planck Institute of Colloids and Interfaces , 14476 Potsdam, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Wagermaier
authors.affiliation: Department of Biological Regulation, Weizmann Institute of Science , Rehovot76100, Israel.
authors.forename: Karina
authors.initials: K
authors.lastname: Yaniv
authors.affiliation: Department of Biomaterials, Max Planck Institute of Colloids and Interfaces , 14476 Potsdam, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Fratzl
authors.affiliation: Department of Structural Biology, Weizmann Institute of Science , Rehovot 76100, Israel.
authors.forename: Lia
authors.initials: L
authors.lastname: Addadi
authors.affiliation: Department of Structural Biology, Weizmann Institute of Science , Rehovot 76100, Israel.
authors.forename: Steve
authors.initials: S
authors.lastname: Weiner
mesh_terms: D000818:Animals; D001842:Bone and Bones / Q000378:metabolism*; D002130:Calcium Phosphates / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007814:Larva / Q000378:metabolism*; D008903:Minerals / Q000378:metabolism*; D013623:Tail; D015027:Zebrafish / Q000378:metabolism*
chemical_list: D002130:Calcium Phosphates; D008903:Minerals