Quantification of chrysolaminarin from the model diatom Phaeodactylum tricornutum

Michael Caballero , Denis Jallet (1) , Libin Shi , Chris Rithner , Yun Zhang , Graham Peers (1)

1 Department of Biology [Fort Collins]

We have established a protocol that allows for parallel quantification of three carbohydrate pools in the marine diatom Phaeodactylum tricornutum. This method utilizes a series of extraction and digestion steps followed by the employment of the 3-methyl-2-benzothiazolinone hydrazone (MBTH) reducing sugar assay. Comparing carbohydrate content between hydrolyzed and non-hydrolyzed soluble extracts enables quantification of soluble, non-reducing carbohydrate. The latter fraction contains chrysolaminarin as verified by H-1 NMR and monomer composition of the purified glucan. We applied this method to investigate carbon partitioning in two experiments. We observed the accumulation of chrysolaminarin during the day and near complete consumption in the dark, supporting its role for fueling heterotrophic metabolism at night. We then observed little change in chrysolaminarin accumulation or consumption during nitrogen starvation, a condition that is known to increase the cellular content of the biofuel precursor triacylglycerol. Overall, this method improves the resolution of major carbohydrate pools in diatoms, complementing physiological and systems biology studies interested in exploring diatom metabolism.

Mots clés: diatoms; Phaeodactylum tricornutum; carbohydrate; chrysolaminarin; nitrogen starvation; carbon partitioning

Domaines: Biologie végétale

Michael Caballero, Denis Jallet, Libin Shi, Chris Rithner, Yun Zhang, et al.. Quantification of chrysolaminarin from the model diatom Phaeodactylum tricornutum. Algal Research - Biomass, Biofuels and Bioproducts, 2016, 20, pp.180-188. ⟨10.1016/j.algal.2016.10.008⟩. ⟨hal-02549574⟩