title: Amorphous calcium carbonate precipitation by cellular biomineralization in mantle cell cultures of Pinctada fucata.
abstract: The growth of molluscan shell crystals is generally thought to be initiated from the extrapallial fluid by matrix proteins, however, the cellular mechanisms of shell formation pathway remain unknown. Here, we first report amorphous calcium carbonate (ACC) precipitation by cellular biomineralization in primary mantle cell cultures of Pinctada fucata. Through real-time PCR and western blot analyses, we demonstrate that mantle cells retain the ability to synthesize and secrete ACCBP, Pif80 and nacrein in vitro. In addition, the cells also maintained high levels of alkaline phosphatase and carbonic anhydrase activity, enzymes responsible for shell formation. On the basis of polarized light microscopy and scanning electron microscopy, we observed intracellular crystals production by mantle cells in vitro. Fourier transform infrared spectroscopy and X-ray diffraction analyses revealed the crystals to be ACC, and de novo biomineralization was confirmed by following the incorporation of Sr into calcium carbonate. Our results demonstrate the ability of mantle cells to perform fundamental biomineralization processes via amorphous calcium carbonate, and these cells may be directly involved in pearl oyster shell formation.
authors.affiliation: Institute of Marine Biotechnology, School of Life Sciences, Tsinghua University, Beijing, China; Laboratory for Reproductive Health, Institute of Biomedicine and Biotechnology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Xiang
authors.affiliation: Institute of Marine Biotechnology, School of Life Sciences, Tsinghua University, Beijing, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Kong
authors.forename: Jing-Tan
authors.initials: JT
authors.lastname: Su
authors.affiliation: Institute of Marine Biotechnology, School of Life Sciences, Tsinghua University, Beijing, China.
authors.forename: Jingtan
authors.initials: J
authors.lastname: Su
authors.affiliation: Institute of Marine Biotechnology, School of Life Sciences, Tsinghua University, Beijing, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Liang
authors.forename: Gui-You
authors.initials: GY
authors.lastname: Zhang
authors.affiliation: Institute of Marine Biotechnology, School of Life Sciences, Tsinghua University, Beijing, China.
authors.forename: Guiyou
authors.initials: G
authors.lastname: Zhang
authors.forename: Li-Ping
authors.initials: LP
authors.lastname: Xie
authors.affiliation: Institute of Marine Biotechnology, School of Life Sciences, Tsinghua University, Beijing, China; Protein Science Laboratory of the Ministry of Education, Tsinghua University, Beijing, China.
authors.forename: Liping
authors.initials: L
authors.lastname: Xie
authors.forename: Rong-Qing
authors.initials: RQ
authors.lastname: Zhang
authors.affiliation: Institute of Marine Biotechnology, School of Life Sciences, Tsinghua University, Beijing, China; Protein Science Laboratory of the Ministry of Education, Tsinghua University, Beijing, China.
authors.forename: Rongqing
authors.initials: R
authors.lastname: Zhang
mesh_terms: D000704:Analysis of Variance; D060105:Animal Shells / Q000378:metabolism*; D000818:Animals; D015153:Blotting, Western; D002119:Calcium Carbonate / Q000378:metabolism*; D002256:Carbonic Anhydrases / Q000378:metabolism; D002478:Cells, Cultured; D011232:Chemical Precipitation; D008855:Microscopy, Electron, Scanning; D049911:Pinctada / Q000166:cytology* / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D017550:Spectroscopy, Fourier Transform Infrared; D014961:X-Ray Diffraction
chemical_list: C101387:nacrein; D002256:Carbonic Anhydrases; D002119:Calcium Carbonate