Browsing by Author "Gouveia, Neide"
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- 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, AnaThe 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.
- Distribution, identification and cytotoxicity of Gambierdiscus (Dinophyceae) in the Atlantic Selvagens Islands (Madeira, Portugal): a ciguatera gateway to EuropePublication . Godinho, Lia; Soliño, Lucia; Churro, Catarina; Timoteo, Viriato; Santos, Carolina; Gouveia, Neide; Diogène, Jorge; Reis Costa, PedroThe emerging threat of ciguatera poisoning (CP) in Europe has been associated with fish captured in the Canary Islands (Spain) and Selvagens Islands (Portugal). The first are heavily populated islands where numerous scientific studies have been carried out. Conversely, the Selvagens Islands are a nature reserve with low human pressure that have been rarely surveyed in terms of the marine benthic microalgae, including the epiphytic ciguatera-causing dinoflagellate species. To investigate the harmful microalgal diversity of the Selvagens Islands, a scientific cruise to these remote islands took place in September, 2018. The Gambierdiscus species composition and distribution, and the associated epiphytic dinoflagellate community, were assessed using artificial substrate devices. Gambierdiscus cells were found in all samples, reaching concentrations of up to 725 cells 100 cm(-2). G. australes was the only species identified after morphological and molecular analysis of the retrieved cultures. Species identification was confirmed by molecular characterization based on the LSU D8-D10 region. Nevertheless, phylogenetic studies indicated that some strains diverged from the G. australes clade suggesting genetic differentiation. Toxicity was estimated by neuro-2a cell-based assay in four strains, ranging from 2.46-83 fg of CTX1B eq. cell(-1). The epiphytic dinoflagellate community that co-occurred with Gambierdiscus comprised other toxic or potentially toxic dinoflagellates, such as Ostreopsis, Prorocentrum, Amphidinium and Coolia species. Oceanographic and meteorological data were also obtained to characterize the occurrence of Gambierdiscus. This study is the first stage in understanding the role of the Selvagens Islands in the incubation and proliferation of the ciguatera-causing dinoflagellates Gambierdiscus in the NE Atlantic.
- New insights into the occurrence of paralytic shellfish toxins in the oceanic pufferfish Lagocephalus lagocephalus (Linnaeus, 1758) from Madeira Island, PortugalPublication . Soliño, Lucia; Gouveia, Neide; Timóteo, Viriato; Reis Costa, PedroPufferfish are some of the most poisonous marine organisms due to their capability to accumulate potent neurotoxins such as tetrodotoxins (TTXs) and paralytic shellfish toxins (PSTs). Several species are consumed, mainly in Asiatic countries, for the quality of their flesh, which may cause severe human poisoning every year due to errors in preparation. Lagocephalus lagocephalus the oceanic pufferfish, is a cosmopolitan species present in European Atlantic and Mediterranean coasts. Although considered toxic, only a few studies have previously addressed the occurrence of toxic compounds in this species. In the present study, 29 individuals of L. lagocephalus caught in Madeira Island (NE Atlantic) were dissected and analysed by HPLC-FLD for PSTs detection. Saxitoxin (STX) and decarbamoyl STX (dcSTX) were detected in liver, intestine and gonads but not in the muscle. Neosaxitoxin (NEO) could also be detected in a liver sample. The total STX equivalent (eq) concentrations in liver ranged from < LOQ to 973.4 μg STX eq kg−1. The presence of toxins in the intestines and gonads points to the fish capability to acquire toxins through feeding or by association with endosymbiotic, toxin-producing microbes as well as the ability to accumulate them in specific organs. Although pufferfish trade in Europe is forbidden by European Union regulations, the increasing occurrence of this species in new areas and the expected raise of blooms of PSTs-producer organisms claims for a better knowledge on oceanic pufferfish toxicity and biology. This will be needed to provide accurate information to stakeholders and population to prevent illegal trade of these species and poisoning incidents.
- Tetrodotoxin and saxitoxin in two native species of puffer fish, Sphoeroides marmoratus and Lagocephalus lagocephalus, from NE Atlantic Ocean (Madeira Island, Portugal)Publication . Pinto, Estefania Pereira; Rodrigues, Susana Margarida; Gouveia, Neide; Timoteo, Viriato; Reis Costa, PedroThe presence in EU waters of invasive tetrodotoxin (TTX) -harbouring puffer fishes has been receiving increasingly attention due to potential new threats posed by this potent neurotoxin. The present study investigates the occurrence of tetrodotoxin, saxitoxin (STX), and their analogues in two native puffer fish species from the NE Atlantic. High TTX content was detected by LC-MS/MS in several tissues of the Guinean puffer Sphoeroides marmoratus from Madeira Island (Portugal), reaching concentrations as high as 15 mg TTX kg(-1) in the digestive tract of a male specimen and 7.4 mg TTX kg(-1) in gonads of a female specimen. Several TTX analogues were also detected, including the 4-epi-TTX, 4,9-Anhydro-TTX, 5- 11- deoxyTTX and 6,11-dideoxyTTX. Although at low levels, STX was detected in liver of the Oceanic puffer Lagocephalus lagocephalus. Trace levels of decarbamoylsaxitoxin (dcSTX) were also observed in L. lagocephalus. This study reports the presence of TTX and STX in native fish from EU waters, highlighting the need for a proper understating of the origin, distribution and fate of these toxins in NE Atlantic.