Browsing by Author "Braga, Ana Catarina"
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- Bioaccessibility of lipophilic and hydrophilic marine biotoxins in seafood: an in vitro digestion approachPublication . Alves, Ricardo N.; Rambla-Alegre, Maria; Braga, Ana Catarina; Maulvault, Ana L.; Barbosa, Vera; Campàs, Mònica; Reverté, Laia; Flores, Cintia; Caixach, Josep; Kilcoyne, Jane; Costa, Pedro Reis; Diogène, Jorge; Marques, AntónioThis study aimed to assess the bioaccessibility of different marine biotoxins in naturally contaminated shellfish and fish gonads using an in vitro digestion methodology. In general, hydrophilic toxins (domoic acid, paralytic shellfish poisoning toxins and tetrodotoxins) showed higher bioaccessibility than lipophilic ones (okadaic acid and azaspiracids). The bioaccessibility of toxins from the okadaic acid group ranged from 69% (raw European razor clams) to 74% (raw donax clams). Regarding azaspiracids, 47% of the initial content was bioaccessible in steamed blue mussel. As for hydrophilic toxins, 100% of the initial content was bioaccessible after digestion in raw shellfish and puffer fish gonads. The total tetrodotoxin bioaccessibility in puffer fish gonads decreased significantly after steaming. The profile of tetrodotoxins changed during the digestion process: TTX and 11-norTTX-6S-ol analogues decreased significantly after digestion, but the 5,6,11-trideoxy TTX analogue increased in both raw and steamed puffer fish gonads. These preliminary findings confirm the need to consider bioaccessibility data in future seafood risk assessment, as such information enables a more accurate and realistic estimation of potential seafood hazards, particularly in what concerns lipophilic toxins, therefore, constituting a crucial tool in the refinement of regulatory limits for the presence of biotoxins in seafood.
- Bivalve shellfish safety in Portugal: variability of faecal levels, metal contaminants and marine biotoxins during the last decade (2011–2020)Publication . Braga, Ana Catarina; Rodrigues, Susana Margarida; Lourenço, Helena Maria; Reis Costa, Pedro; Pedro, SóniaBivalves are a high-value product whose production has markedly increased, reaching 9863 tonnes in Portugal in 2021. Bivalves' habitats-lagoons, estuaries and coastal waters-are exposed to biological and anthropogenic contaminants, which can bioaccumulate in these organisms and pose a significant public health risk. The need to obtain a safe product for human consumption led to the implementation of standardised hygiene regulations for harvesting and marketing bivalve molluscs, resulting in routine monitoring of bivalve production areas for microbial quality, metal contaminants, and marine biotoxins. While excessive levels of biotoxins and metal contamination lead to temporary harvesting bans, high faecal contamination leads to area reclassification and impose post-harvest treatments. In this study, the seasonal and temporal variability of these parameters were analysed using historical data generated by the monitoring programme during the last decade. Moreover, the impact of the monitoring program on bivalve harvesting from 2011 to 2020 was assessed. This program presented a considerable improvement over time, with an increase in the sampling effort and the overall program representativeness. Finally, contamination risk, revising control measures, and defining recommendations for risk mitigation measures are given in the light of ten years' monitoring.
- 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, PedroTetrodotoxin (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.
- Gymnodinium catenatum paralytic Shellfish toxin production and photobiological responses under marine heat wavesPublication . Lopes, Vanessa M.; Court, Mélanie; Seco, Martim Costa; Borges, Francisco O.; Vicente, Bernardo; Lage, Sandra; Braga, Ana Catarina; Duarte, Bernardo; Santos, Catarina Frazão; Amorim, Ana; Reis Costa, Pedro; Rosa, RuiMarine heatwaves (MHWs) have doubled in frequency since the 1980s and are projected to be exacerbated during this century. MHWs have been shown to trigger harmful algal blooms (HABs), with severe consequences to marine life and human populations. Within this context, this study aims to understand, for the first time, how MHWs impact key biological and toxicological parameters of the paralytic shellfish toxin (PST) producer Gymnodinium catenatum, a dinoflagellate inhabiting temperate and tropical coastal waters. Two MHW were simulated—category I (i.e., peak: 19.9 ◦C) and category IV (i.e., peak: 24.1 ◦C)—relative to the estimated baseline in the western coast of Portugal (18.5 ◦C). No significant changes in abundance, size, and photosynthetic efficiency were observed among treatments. On the other hand, chain-formation was significantly reduced under category IV MHW, as was PSP toxicity and production of some PST compounds. Overall, this suggests that G. catenatum may have a high tolerance to MHWs. Nevertheless, some sublethal effects may have occurred since chain-formation was affected, suggesting that these growth conditions may be sub-optimal for this population. Our study suggests that the increase in frequency, intensity, and duration of MHWs may lead to reduced severity of G. catenatum blooms.
- In vitro bioaccessibility of the marine biotoxins okadaic acid, dinophysistoxin-2 and their 7-O-acyl fatty acid ester derivatives in raw and steamed shellfishPublication . Manita, Diana; Alves, Ricardo N.; Braga, Ana Catarina; Fogaca, Fabiola H. S.; Marques, Antonio; Reis Costa, PedroOkadaic acid (OA), Dinophysistoxins (DTX1 and DTX2) and their acyl-derivatives (DTX3) are marine toxins responsible for the human diarrhetic shellfish poisoning. To date the amount of toxins ingested from consumption of shellfish has been considered equal to the amount of toxins available for uptake by the human body. The aim of this study is to assess the OA, DTX2 and DTX3 fractions released from raw and steamed mussels and cockles into the digestive fluids (bioaccessibility) using a static in vitro digestion model. Higher bioaccessibility was found in mussels (86 +/- 4%) than in cockles (59 +/- 9%). A significant reduction of ester derivatives of OA and an increase of OA were observed in the bioaccessible fraction of mussel samples, suggesting that DTX3 undergo conversion into their more toxic parent compounds during human digestion. However, similar increase of DTX2 and reduction of the respective acyl derivatives was not observed. Steaming lead to significant reduction of OA and analogues bioaccessibility in both species even though increased concentrations of toxins are obtained after this treatment. Risk assessment based solely on DSP toxins occurrence in seafood can conduct to an overestimation of the exposure and lead to more conservative regulatory measures. (C) 2017 Elsevier Ltd. All rights reserved.
- Lipophilic marine toxins in sediments from Arrábida marine protected area, Portugal (NE Atlantic)Publication . Soliño, Lucia; Braga, Ana Catarina; Lobo-Arteaga, Jorge; Reis Costa, PedroDuring the development and senescence of harmful algal blooms (HAB), most of the algae cells not ingested by grazers or filter-feeding organisms sink to the bottom, making sediments important reservoirs of algae toxins. In this study, lipophilic marine toxins were determined in the sediments collected from depths ranging from 5 to 145 m depth in the marine protected area of Arrabida ´ (southwest Portuguese coast). Sediments were characterized in terms of granulometry, water and organic matter content. The toxins were determined by liquid chromatography with tandem mass spectrometry. Okadaic acid (OA), dinophysistoxin-2 (DTX2), and azaspiracid-2 (AZA2), reaching concentrations up to 3.4, 1.3, and 0.13 ng/g, respectively, were found. A trend in the occurrence of DTX2 and AZA2 with sediment water and organic matter content was observed, as well as with AZA2 and depth. This study highlights the need to further investigate sediment deposition of toxins and their availability for bottom-dwelling organisms and its contamination.
- Lipophilic marine toxins in sediments from Arrábida marine protected area, Portugal (NE Atlantic)Publication . Soliño, Lucia; Braga, Ana Catarina; Lobo-Arteaga, Jorge; Reis Costa, PedroDuring the development and senescence of harmful algal blooms (HAB), most of the algae cells not ingested by grazers or filter-feeding organisms sink to the bottom, making sediments important reservoirs of algae toxins. In this study, lipophilic marine toxins were determined in the sediments collected from depths ranging from 5 to 145 m depth in the marine protected area of Arrabida (southwest Portuguese coast). Sediments were characterized in terms of granulometry, water and organic matter content. The toxins were determined by liquid chromatography with tandem mass spectrometry. Okadaic acid (OA), dinophysistoxin-2 (DTX2), and azaspiracid-2 (AZA2), reaching concentrations up to 3.4, 1.3, and 0.13 ng/g, respectively, were found. A trend in the occurrence of DTX2 and AZA2 with sediment water and organic matter content was observed, as well as with AZA2 and depth. This study highlights the need to further investigate sediment deposition of toxins and their availability for bottom-dwelling organisms and its contamination.
- Photochemical treatment strategies for okadaic acid degradation: Effects of salinity, oxidants, and UV sourcesPublication . Moreno-Andrés, Javier; Lage, Sandra; Braga, Ana Catarina; Reis Costa, PedroThis study evaluates the degradation and detoxification of okadaic acid (OA), a marine biotoxin, through UVassisted photochemical processes using environmentally relevant OA concentrations. Experiments were conducted in distilled water (DW) and artificial seawater (ASW), applying two UV sources: UV-LED (lambda(max) = 275 nm) and low-pressure mercury lamp (LP-Hg; lambda = 254 nm), combined with hydrogen peroxide (HP), sodium peroxydisulfate (PDS), and potassium peroxymonosulfate (PMS). Photolysis alone was ineffective, and kinetic rate constants (k(obs); min(-1)) followed the trend UV/PMS > UV/PDS > UV/HP for both UV sources. While all treatments showed high OA removal (>79 %) in DW, degradation was significantly reduced for HP (72.8 %-89.9 %) and PDS (67.8 %-76.6 %) in ASW. In contrast, UV/PMS efficacy improved in saline media, achieving rapid and effective degradation of OA, and reaching 99 % detoxification (PP2A activity) within 15 min. The main transformation product, norokadanone (m/z 757.453), formed via decarboxylation, showed significantly reduced toxicity compared to OA. These results confirm the suitability of sulfate radical-based processes (particularly UV/ PMS) for OA mitigation in marine environments. In addition, this work highlights the critical role of water matrix composition in marine toxin treatment and supports the development of scalable, mercury-free strategies for effectively mitigating hazardous compounds in coastal environments.