Comparison of methods for DMSP measurements in dinoflagellate cultures

Amandine Caruana (1) , Eva Bucciarelli (2) , Céline Deleporte (1) , Emilie Le Floc'H (3) , Fabienne Hervé (1) , Manon Le Goff (2)

1 PHYTOX - Unité Physiologie et Toxines des Microalgues Toxiques et Nuisibles
2 LEMAR - Laboratoire des Sciences de l'Environnement Marin (LEMAR)
3 UMR MARBEC - MARine Biodiversity Exploitation and Conservation - MARBEC

A comparison of three analytical methods (the indirect GC‐FPD and MIMS, and direct LC‐MS/MS) for dimethylsulfoniopropionate (DMSP) measurements was conducted to assess their accuracy and reliability. The three methods showed a linear response but are distinguished by their linearity range, the largest being for MIMS. All three methods showed good precision on Alexandrium minutum samples (2–12%). The variability between the three methods when comparing analyses of A. minutum replicates was 11%, with the DMSP measurements by LC‐MS/MS being the highest. This result also confirms that indirect DMSP measurement after hydrolysis for GC or MIMS methods does not lead to an overestimation of DMSP values in A. minutum . A special focus was made on the more recent LC‐MS/MS method including further assays in sample preparation and storage from cultures of the dinoflagellate A. minutum . Dinoflagellate cells should be harvested by gentle filtration (< 5 cm Hg) or slow centrifugation (500 × g ) to retrieve the largest DMSP pool. For the LC‐MS/MS method, MeOH used for cell extraction should be added prior to freezing (to prevent DMSP degradation). Samples will then be stable in frozen storage for at least 2 months. Finally, direct and indirect methods are complementary for identifying the exact DMSP fraction among dimethylsulfide‐producing compounds that compose total and particulate DMSP pools issued from newly screened organisms or environmental samples.

Domaines: Sciences du Vivant [q-bio]

Amandine Caruana, Eva Bucciarelli, Céline Deleporte, Emilie Le Floc'H, Fabienne Hervé, et al.. Comparison of methods for DMSP measurements in dinoflagellate cultures. Limnology and Oceanography: Methods, 2024, ⟨10.1002/lom3.10618⟩. ⟨hal-04567173⟩