title: The uronic acid content of coccolith-associated polysaccharides provides insight into coccolithogenesis and past climate.
abstract: Unicellular phytoplanktonic algae (coccolithophores) are among the most prolific producers of calcium carbonate on the planet, with a production of ∼1026coccoliths per year. During their lith formation, coccolithophores mainly employ coccolith-associated polysaccharides (CAPs) for the regulation of crystal nucleation and growth. These macromolecules interact with the intracellular calcifying compartment (coccolith vesicle) through the charged carboxyl groups of their uronic acid residues. Here we report the isolation of CAPs from modern day coccolithophores and their prehistoric predecessors and we demonstrate that their uronic acid content (UAC) offers a species-specific signature. We also show that there is a correlation between the UAC of CAPs and the internal saturation state of the coccolith vesicle that, for most geologically abundant species, is inextricably linked to carbon availability. These findings suggest that the UAC of CAPs reports on the adaptation of coccolithogenesis to environmental changes and can be used for the estimation of past CO2concentrations.
authors: Department of Earth Sciences, University of Oxford, Oxford OX1 3AN, UK.|School of Biological Sciences, University of Reading, Whiteknights, Reading RG6 6UB, UK.
authors: Renee B Y
authors: RB
authors: Lee
authors: MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College London, London SW7 2DD, UK.|Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK.
authors: Despoina A I
authors: DA
authors: Mavridou
authors: Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK.
authors: Grigorios
authors: G
authors: Papadakos
authors: Department of Earth Sciences, University of Oxford, Oxford OX1 3AN, UK.
authors: Harry L O
authors: HL
authors: McClelland
authors: Department of Earth Sciences, University of Oxford, Oxford OX1 3AN, UK.
authors: Rosalind E M
authors: RE
authors: Rickaby
mesh_terms: D000222:Adaptation, Physiological; D002113:Calcification, Physiologic; D002119:Calcium Carbonate / Q000737:chemistry* / Q000266:history / Q000378:metabolism; D002244:Carbon / Q000737:chemistry* / Q000266:history / Q000378:metabolism; D002245:Carbon Dioxide / Q000737:chemistry / Q000266:history / Q000378:metabolism; D003460:Crystallization; D005580:Fossils / Q000266:history; D058087:Haptophyta / Q000737:chemistry* / Q000145:classification / Q000378:metabolism; D049690:History, Ancient; D010163:Paleontology; D010839:Phytoplankton / Q000737:chemistry* / Q000145:classification / Q000378:metabolism; D011134:Polysaccharides / Q000737:chemistry* / Q000266:history / Q000378:metabolism; D013045:Species Specificity; D014574:Uronic Acids / Q000737:chemistry* / Q000266:history / Q000378:metabolism
chemical_list: D011134:Polysaccharides; D014574:Uronic Acids; D002245:Carbon Dioxide; D002244:Carbon; D002119:Calcium Carbonate