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A vacuole-like compartment concentrates a disordered calcium phase in a key coccolithophorid alga.

Sviben S, Gal A, Hood MA, Bertinetti L, Politi Y, Bennet M, Krishnamoorthy P, Schertel A, Wirth R, Sorrentino A, Pereiro E, Faivre D, Scheffel A - Nat Commun (2016)

Bottom Line: We identify a compartment, distinct from the coccolith-producing compartment, filled with high concentrations of a disordered form of calcium.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.

View Article: PubMed Central - PubMed

Affiliation: Max-Planck Institute of Molecular Plant Physiology, Potsdam-Golm 14476, Germany.

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.

No MeSH data available.


Related in: MedlinePlus

Confocal fluorescence microscopy images of live E. huxleyi.Cells were dual-stained with DAPI and the membrane-permeable calcium staincalcein-AM. The emitted fluorescence in the wavelength window between 420and 450 nm originates from DAPI–DNA andDAPI–polyphosphate complexes, whereas the emission between 500 and550 nm originates from DAPI bound to polyphosphate. The red channelshows the auto-fluorescence of chlorophyll.
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f5: Confocal fluorescence microscopy images of live E. huxleyi.Cells were dual-stained with DAPI and the membrane-permeable calcium staincalcein-AM. The emitted fluorescence in the wavelength window between 420and 450 nm originates from DAPI–DNA andDAPI–polyphosphate complexes, whereas the emission between 500 and550 nm originates from DAPI bound to polyphosphate. The red channelshows the auto-fluorescence of chlorophyll.

Mentions: We tested our polyphosphate hypothesis by live-cell confocal fluorescencemicroscopy using the fluorescent dye 4′,6-diamidino-2-phenylindole (DAPI),which has been widely used to stain polyphosphates30, and themembrane-permeable calcium stain calcein-AM. The co-localized fluorescencesignals from both the dyes in a compartment distinct from the nucleus and thecoccolith vesicle–reticular body system (Fig. 5) areconsistent with our EDX results that strongly suggest that polyphosphate iscomplexing Ca in the Ca-rich compartment.


A vacuole-like compartment concentrates a disordered calcium phase in a key coccolithophorid alga.

Sviben S, Gal A, Hood MA, Bertinetti L, Politi Y, Bennet M, Krishnamoorthy P, Schertel A, Wirth R, Sorrentino A, Pereiro E, Faivre D, Scheffel A - Nat Commun (2016)

Confocal fluorescence microscopy images of live E. huxleyi.Cells were dual-stained with DAPI and the membrane-permeable calcium staincalcein-AM. The emitted fluorescence in the wavelength window between 420and 450 nm originates from DAPI–DNA andDAPI–polyphosphate complexes, whereas the emission between 500 and550 nm originates from DAPI bound to polyphosphate. The red channelshows the auto-fluorescence of chlorophyll.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4834641&req=5

f5: Confocal fluorescence microscopy images of live E. huxleyi.Cells were dual-stained with DAPI and the membrane-permeable calcium staincalcein-AM. The emitted fluorescence in the wavelength window between 420and 450 nm originates from DAPI–DNA andDAPI–polyphosphate complexes, whereas the emission between 500 and550 nm originates from DAPI bound to polyphosphate. The red channelshows the auto-fluorescence of chlorophyll.
Mentions: We tested our polyphosphate hypothesis by live-cell confocal fluorescencemicroscopy using the fluorescent dye 4′,6-diamidino-2-phenylindole (DAPI),which has been widely used to stain polyphosphates30, and themembrane-permeable calcium stain calcein-AM. The co-localized fluorescencesignals from both the dyes in a compartment distinct from the nucleus and thecoccolith vesicle–reticular body system (Fig. 5) areconsistent with our EDX results that strongly suggest that polyphosphate iscomplexing Ca in the Ca-rich compartment.

Bottom Line: We identify a compartment, distinct from the coccolith-producing compartment, filled with high concentrations of a disordered form of calcium.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.

View Article: PubMed Central - PubMed

Affiliation: Max-Planck Institute of Molecular Plant Physiology, Potsdam-Golm 14476, Germany.

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.

No MeSH data available.


Related in: MedlinePlus