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Toxin profile of Ostreopsis cf. ovata from Portuguese continental coast and Selvagens Islands (Madeira, Portugal)
Publication . Soliño, Lucia; Garcia-Altares, Maria; Godinho, Lia; Reis Costa, Pedro
The toxigenic dinoflagellate Ostreopsis cf. ovata is known to produce a range of palytoxin (PLTX) - related compounds named ovatoxins (OVTX). O. cf. ovata presents a wide variability in toxin production and its toxic profile is strain-specific. Several OVTXs, denominated from -a to -h and -I have been reported from different strains of this benthic microalgae up to now, mainly in Mediterranean isolates. However, less is known about the toxin profile of the strains present in the Atlantic coasts of Europe. In this work, strains of O. cf. ovata isolated from the South coast of Portugal mainland (Algarve) and Selvagens Island (Madeira, Portugal) were cultured and tested for toxicity by hemolytic assay. Toxin profiles were qualitatively elucidated by Liquid Chromatography-High Resolution Mass Spectrometry (LC-HRMS). The strain from Algarve presented lower toxic potency than the strain from Selvagens island (12.3 against 54.8 pg of PLTX equivalents per cell) showing in both cases the characteristic toxin profile of Mediterranean strains. The major component, OVTX-a, was concomitant with OVTX from -b to -g and isobaric PLTX. Regarding the morphological characteristics of these strains, as well as their toxin fingerprint, it is likely they are closely related to strains from Mediterranean coasts. The present study reports for the first time the occurrence of several OVTX congeners and iso-PLTX in O. cf. ovata from Portuguese waters. This study provides valuable information to characterize the risk of OVTXs-related outbreaks in Portugal.
An update on ciguatoxins and CTX-like toxicity in fish from different trophic levels of the Selvagens Islands (NE Atlantic, Madeira, Portugal)
Publication . Reis Costa, Pedro; Estévez, Pablo; Soliño, Lucia; Castro, David; Rodrigues, Susana Margarida; Timoteo, Viriato; Leao-Martins, José Manuel; Santos, Carolina; Gouveia, Neide; Diogène, Jorge; Gago-Martínez, Ana
The Selvagens Islands, which are a marine protected area located at the southernmost point of the Portuguese maritime zone, have been associated with fish harboring ciguatoxins (CTX) and linked to ciguatera fish poisonings. This study reports the results of a field sampling campaign carried out in September 2018 in these remote and rarely surveyed islands. Fifty-six fish specimens from different trophic levels were caught for CTX-like toxicity determination by cell-based assay (CBA) and toxin content analysis by liquid chromatography with tandem mass spectrometry (LC-MS/MS). Notably, high toxicity levels were found in fish with an intermediate position in the food web, such as zebra seabream (Diplodus cervinus) and barred hogfish (Bodianus scrofa), reaching levels up to 0.75 µg CTX1B equivalent kg−1 . The LC-MS/MS analysis confirmed that C-CTX1 was the main toxin, but discrepancies between CBA and LC-MS/MS in D. cervinus and top predator species, such as the yellowmouth barracuda (Sphyraena viridis) and amberjacks (Seriola spp.), suggest the presence of fish metabolic products, which need to be further elucidated. This study confirms that fish from coastal food webs of the Selvagens Islands represent a high risk of ciguatera, raising important issues for fisheries and environmental management of the Selvagens Islands.

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Fundação para a Ciência e a Tecnologia

Funding programme

9471 - RIDTI

Funding Award Number

151746

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