title: A vacuole-like compartment concentrates a disordered calcium phase in a key coccolithophorid alga.
abstract: Coccoliths are calcitic particles produced inside the cells of unicellular marine algae known as coccolithophores. They are abundant components of sea-floor carbonates, and the stoichiometry of calcium to other elements in fossil coccoliths is widely used to infer past environmental conditions. Here we study cryo-preserved cells of the dominant coccolithophore Emiliania huxleyi using state-of-the-art nanoscale imaging and spectroscopy. We identify a compartment, distinct from the coccolith-producing compartment, filled with high concentrations of a disordered form of calcium. Co-localized with calcium are high concentrations of phosphorus and minor concentrations of other cations. The amounts of calcium stored in this reservoir seem to be dynamic and at a certain stage the compartment is in direct contact with the coccolith-producing vesicle, suggesting an active role in coccolith formation. Our findings provide insights into calcium accumulation in this important calcifying organism.
authors.affiliation: Max-Planck Institute of Molecular Plant Physiology, Potsdam-Golm 14476, Germany.
authors.forename: Sanja
authors.initials: S
authors.lastname: Sviben
authors.affiliation: Max-Planck Institute of Molecular Plant Physiology, Potsdam-Golm 14476, Germany.|Department of Biomaterials, Max-Planck Institute of Colloids and Interfaces, Potsdam-Golm 14476, Germany.
authors.forename: Assaf
authors.initials: A
authors.lastname: Gal
authors.affiliation: Max-Planck Institute of Molecular Plant Physiology, Potsdam-Golm 14476, Germany.|Department of Biomaterials, Max-Planck Institute of Colloids and Interfaces, Potsdam-Golm 14476, Germany.
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Hood
authors.affiliation: Department of Biomaterials, Max-Planck Institute of Colloids and Interfaces, Potsdam-Golm 14476, Germany.
authors.forename: Luca
authors.identifier: http://orcid.org/0000-0002-4666-9610
authors.initials: L
authors.lastname: Bertinetti
authors.affiliation: Department of Biomaterials, Max-Planck Institute of Colloids and Interfaces, Potsdam-Golm 14476, Germany.
authors.forename: Yael
authors.initials: Y
authors.lastname: Politi
authors.affiliation: Department of Biomaterials, Max-Planck Institute of Colloids and Interfaces, Potsdam-Golm 14476, Germany.
authors.forename: Mathieu
authors.initials: M
authors.lastname: Bennet
authors.affiliation: Max-Planck Institute of Molecular Plant Physiology, Potsdam-Golm 14476, Germany.
authors.forename: Praveen
authors.initials: P
authors.lastname: Krishnamoorthy
authors.affiliation: Carl Zeiss Microscopy GmbH, Global Applications Support, Oberkochen 73447, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Schertel
authors.affiliation: Department of Geomaterials, GeoForschungsZentrum Potsdam, Potsdam 14473, Germany.
authors.forename: Richard
authors.initials: R
authors.lastname: Wirth
authors.affiliation: ALBA Synchrotron Light Source, Cerdanyola del Vallés, Barcelona 08290, Spain.
authors.forename: Andrea
authors.initials: A
authors.lastname: Sorrentino
authors.affiliation: ALBA Synchrotron Light Source, Cerdanyola del Vallés, Barcelona 08290, Spain.
authors.forename: Eva
authors.initials: E
authors.lastname: Pereiro
authors.affiliation: Department of Biomaterials, Max-Planck Institute of Colloids and Interfaces, Potsdam-Golm 14476, Germany.
authors.forename: Damien
authors.initials: D
authors.lastname: Faivre
authors.affiliation: Max-Planck Institute of Molecular Plant Physiology, Potsdam-Golm 14476, Germany.
authors.forename: André
authors.initials: A
authors.lastname: Scheffel
mesh_terms: D002118:Calcium / Q000378:metabolism*; D002451:Cell Compartmentation; D020285:Cryoelectron Microscopy; D058087:Haptophyta / Q000378:metabolism* / Q000648:ultrastructure; D042541:Intracellular Space / Q000378:metabolism; D018613:Microscopy, Confocal; D010758:Phosphorus / Q000378:metabolism; D014617:Vacuoles / Q000378:metabolism*; D014965:X-Rays
chemical_list: D010758:Phosphorus; D002118:Calcium