Pseudo-nitzschia sp. cf. pseudodelicatissima: a confirmed producer of domoic acid from the northern Gulf of Mexico

Par Conseil national de recherches du Canada

DOI	Trouver le DOI : https://doi.org/10.3354/meps220083
Auteur	Rechercher : Pan, Youlian Identifiant ORCID : https://orcid.org/0000-0002-0158-0081; Rechercher : Parsons, Michael L.; Rechercher : Busman, Mark; Rechercher : Moeller, Peter D. R.; Rechercher : Dortch, Quay; Rechercher : Powell, Christine L.; Rechercher : Doucette, Gregory J.
Format	Texte, Article
Sujet	pseudo-nitzschia; domoic acid; harmful algal blooms; receptor-binding assay; Gulf of Mexico
Résumé	Domoic acid (DA), a potent neurotoxin, is synthesized by certain members of the ubiquitous marine diatom genus Pseudo-nitzschia. We recently detected elevated concentrations of DA in phytoplankton field samples from the northern Gulf of Mexico. In searching for a possible source of the toxin, we used a receptor-binding assay to detect DA activity in cultures of P. sp. cf. pseudodelicatissima (Hasle) isolated from this region and confirmed its presence in 2 of 7 clones using liquid chromatography coupled with tandem mass-spectrometric detection (LC-MS/MS). Unlike other toxic Pseudo-nitzschia species examined previously (e.g., P. multiseries, P. australis), cellular levels and net production of DA in these clones were highest in the early exponential phase, while the population growth rate was high and cell concentration was low. There was a negative correlation between cellular DA and cell concentration. The maximum cellular DA activity in cultures was 36 fg DA equiv. cell–1. No net toxin production was evident in the stationary phase, yet extracellular DA levels increased markedly during this period to as much as 88% of the total DA in the cultures. Interestingly, these 2 toxic clones were able to enlarge their cell size after the apical axes declined to 15 to 25 μm, and these larger cells had considerably higher levels of DA than the original small cells. This study unequivocally establishes P. sp. cf. pseudodelicatissima as a source of DA in the northern Gulf of Mexico. Moreover, our work suggests that rapidly growing, rather than nutrient-limited, populations of this diatom should yield maximum net DA production rates and DA cell quotas. Thus, the presence of P. sp. cf. pseudodelicatissima cells, even at the low levels of early, rapidly growing bloom stages, can potentially lead to toxic events.
Date de publication	2001-09-27
Maison d’édition	Inter-Research Science Publisher
Dans	Marine Ecology Progress Series (MEPS) 220 (27 septembre 2001) : 83–92.
Langue	anglais
Publications évaluées par des pairs	Oui
Publication du CNRC	Cette publication n’est pas du CNRC Ce sont des publications qui ont été rédigées par un auteur du CNRC, mais avant que celui-ci soit employé du CNRC.
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Date de modification :: 2025-07-16