The rise of toxic tropical and subtropical marine dinoflagellates Gambierdiscus spp: distribution, ciguatoxins trophic transfer and risk of ciguatera fish poisoning

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Cytotoxic and hemolytic activities of extracts of the fish parasite dinoflagellate amyloodinium ocellatum

Publication . Moreira, Márcio; Soliño, Lucia; Marques, Cátia L.; Laizé, Vincent; Pousão-Ferreira, Pedro; Fidalgo E Costa, Pedro; Soares, Florbela

The dinoflagellate Amyloodinium ocellatum is the etiological agent of a parasitic disease named amyloodiniosis. Mortalities of diseased fish are usually attributed to anoxia, osmoregulatory impairment, or opportunistic bacterial infections. Nevertheless, the phylogenetic proximity of A. ocellatum to a group of toxin-producing dinoflagellates from Pfiesteria, Parvodinium and Paulsenella genera suggests that it may produce toxin-like compounds, adding a new dimension to the possible cause of mortalities in A. ocellatum outbreaks. To address this question, extracts prepared from different life stages of the parasite were tested in vitro for cytotoxic effects using two cell lines derived from branchial arches (ABSa15) and the caudal fin (CFSa1) of the gilthead seabream (Sparus aurata), and for hemolytic effects using erythrocytes purified from the blood of gilthead seabream juveniles. Cytotoxicity and a strong hemolytic effect, similar to those observed for Karlodinium toxins, were observed for the less polar extracts of the parasitic stage (trophont). A similar trend was observed for the less polar extracts of the infective stage (dinospores), although cell viability was only affected in the ABSa15 line. These results suggest that A. ocellatum produces tissue-specific toxic compounds that may have a role in the attachment of the dinospores’ and trophonts’ feeding process.

2022-07-08Journal article

Open access

Does Ocean Sunfish Mola spp. (Tetraodontiformes: Molidae) represent a risk for Tetrodotoxin Poisoning in the Portuguese Coast?

Publication . Baptista, Miguel; Braga, Ana Catarina; Rosa, Rui; Reis Costa, Pedro

Tetrodotoxin (TTX) is a potent neurotoxin naturally occurring in terrestrial and marine organisms such as pufferfish. Due to the risk of TTX poisoning, fish of Tetraodontidae family and other puffer-related species must not be placed in the EU markets. This restriction applies to fish of the family Molidae even though no data on toxins’ occurrence is available. In this study, the presence of TTX and its analogues was investigated in the main edible tissue (the white muscle) and the main xenobiotics storage organ (the liver) of ocean sunfish Mola spp. (n = 13) from the South Portuguese coast. HILIC-MS/MS analyses did not reveal TTX in the analyzed samples, suggesting an inexistent or very limited risk of TTX poisoning

2022-09-23Journal article

Open access