Instituto Nacional dos Recursos Biologicos

Vale de Cambra, Portugal

Instituto Nacional dos Recursos Biologicos

Vale de Cambra, Portugal
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Vale P.,Instituto Nacional dos Recursos Biologicos | Band-Schmidt C.,National Polytechnic Institute of Mexico
Toxicon | Year: 2011

Benzoate type toxins have been described as an important component of Gymnodinium catenatum cells. In this paper we study these toxins in a G. catenatum strain isolated from the Mexican coast. A partition of the toxins was done by solid-phase extraction on a COOH cartridge and detected by HPLC coupled to fluorescence after pre-column periodate oxidation. Two groups of the hydrophobic analogues of saxitoxin were identified: those containing a sulphate group in the benzoate moiety instead of a hydroxyl group like GC1/2 or GC3 and the hydroxy-benzoate analogues, with a sulphate group at the eleventh position of the STX core present or absent (GCs-GTX and GCs-STX analogues, respectively). These toxins are more abundant, in a relative basis, when comparing with a G. catenatum toxin content isolated from Portugal. This is the first report of the presence of these toxins in a Mexican strain. © 2011 Elsevier Ltd.

Costa P.M.,New University of Lisbon | Caeiro S.,New University of Lisbon | Caeiro S.,University of Lisbon | Vale C.,Instituto Nacional Dos Recursos Biologicos | Costa M.H.,New University of Lisbon
Environmental Pollution | Year: 2012

Surveying toxicity of complex geochemical media as aquatic sediments often yields results that are either difficult to interpret or even contradictory to acknowledged theory. Multi-level biomarkers were investigated in a benthic fish exposed to estuarine sediments through laboratory and in situ bioassays, to evaluate their employment either in ecological risk assessment or in more mechanistic approaches to assess sediment-bound toxicity. Biomarkers reflecting lesions (such as genotoxicity or histopathology), regardless of their low or absent specificity to contaminants, are efficient in segregating exposure to contaminated from uncontaminated sediments even when classical biomarkers like CYP1A and metallothionein induction are inconclusive. Conversely, proteomics and gene transcription analyses provided information on the mechanics of toxicity and aided explaining response variation as a function of metabolic imbalance and impairment of defences against insult. In situ bioassays, although less expedite and more affected by confounding factors, produced data better correlated to overall sediment contamination. © 2011 Elsevier Ltd. All rights reserved.

Dias A.S.,Instituto Nacional dos Recursos Biologicos | Semedo J.,Instituto Nacional dos Recursos Biologicos | Ramalho J.C.,Bioquim ca e Biotecnologi Vegetae Institute Investigacao Cientifica Tropical | Lidon F.C.,New University of Lisbon
Journal of Agronomy and Crop Science | Year: 2011

The photosynthetic responses to heat stress, during grain filling, in four genotypes of Triticum aestivum L. (Sever and Golia) and Triticum turgidum subsp. durum (Acalou and TE 9306), chosen according to its genetic background diversity, were investigated. All wheat genotypes (excepting Golia) showed synergistic trends implicating the internal CO2 concentration, net photosynthesis and stomatal conductance. Additionally, the modifications of net photosynthesis were associated with changes in stomatal control. Chlorophyll a fluorescence parameters (minimal fluorescence, maximal and variable fluorescence, intrinsic efficiency of PSII in darkness, non-photochemical quenching, photochemical quenching and energy-dependent chlorophyll fluorescence quenching) further pointed heat protective mechanisms, implicating Fv/Fm stabilization (i.e. maintaining the efficiency of PS II) and electron transport rate preservation. It is concluded that, comparatively to bread wheat, the photosynthetic performance of durum wheat is more tolerant to heat stress, as stomatal conductance and transpiration are less affected. © 2010 Blackwell Verlag GmbH.

Frias J.P.G.L.,New University of Lisbon | Sobral P.,New University of Lisbon | Ferreira A.M.,Instituto Nacional dos Recursos Biologicos
Marine Pollution Bulletin | Year: 2010

Microplastics pose a threat to coastal environments due to their capacity to adsorb persistent organic pollutants (POPs). These particles (less than 5. mm in size) are potentially dangerous to marine species due to magnification risk over the food chain. Samples were collected from two Portuguese beaches and sorted in four classes to relate the adsorption capacity of pollutants with color and age. Polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and DDTs were analysed on pellets through gas chromatography mass spectrometry (GC-MS), and types of plastic were identified using Fourier transformed infra-red spectroscopy (micro-FTIR). Microplastics were mostly polyethylene and polypropylene. Regarding sizes, some fibres ranged from 1 to 5μm in diameter and were 500μm in length. The majority of samples collected had sizes above 200μm. Black pellets, unlike aged pellets, had the highest concentrations of POPs except for PAHs in Fonte da Telha beach. PAHs with higher concentrations were pyrene, phenantrene, chrysene and fluoranthene. Higher concentrations of PCBs were found for congeners 18, 31, 138 and 187. Further investigation is necessary to understand the relationship between plastic degradation and adsorption for different pollutants. © 2010 Elsevier Ltd.

Roseiro L.C.,Instituto Nacional dos Recursos Biologicos | Gomes A.,Instituto Nacional dos Recursos Biologicos | Santos C.,Instituto Nacional dos Recursos Biologicos
Food and Chemical Toxicology | Year: 2011

The concentration of 16 polycyclic aromatic hydrocarbons (PAHs) was determined in traditional dry/fermented sausage along distinct stages of processing under two different technological procedures (traditional and modified processes). The influence of product's position in the smoking room, on the variation of contaminants and in their migration dynamics from the outer into the inner part, was also followed up. Raw material mixtures presented expressive total PAH values, 106.17μgkg-1 in wet samples and 244.34μgkg-1 in dry mater (DM), expressing the frequent fire woods occurred in the regions pigs were extensively reared. Traditional processing produced a higher (p<0.01) total PAH levels comparatively to modified/industrial procedures, with mean values reaching 3237.10 and 1702.85μgkg-1 DM, respectively. Both, raw materials and final products, showed PAH profiles with light compounds representing about 99.0% of the total PAHs, mostly accounted by those having two rings (naphthalene-27.5%) or three rings (acenaphtene-16.9%; fluorene-27.1%; phenanthrene-19.5% and anthracene-3.9%). The benzo[a]pyrene (BaP) accumulated in traditional and modified processed products never surpassed the limit of 5μgkg-1 established by the EU legislation. PAHs in products hanged in bars closer to heating/smoking source speed up their transfer from the surface/outer portion to the inner part of the product. © 2011 Elsevier Ltd.

Vale P.,Instituto Nacional dos Recursos Biologicos
Food Chemistry | Year: 2011

The paralytic shellfish poisoning (PSP) toxin producer Gymnodinium catenatum produces several hydrophobic analogues of saxitoxin (STX). These are poorly studied due to their recent discovery and lack of standards. It was previously observed these hydrophobic analogues could be partially hydrolysed, loosing its benzoate moiety during alkaline oxidation to obtain fluorescent products measurable by HPLC analysis. The hydrolysis reaction was further explored to study two practical aspects. One was the indirect measurement of these compounds through its hydrolysis products: the decarbamoyl analogues of STX. The second one was to simplify standard production of decarbamoyl analogues, which are commonly found in contaminated shellfish products.PSP analogues are unstable in alkaline media. The hydrolysis of benzoate analogues progressed rapidly with increasing base amount, but the decarbamoylgonyautoxin type hydrolysis products were short lived and converted into decarbamoylsaxitoxin type analogues. For a rapid estimation of the presence of these benzoate analogues in seafood, decarbamoylgonyautoxin type analogues can only be measured as decarbamoylsaxitoxin type equivalents.For production of standards, complete hydrolysis of hydroxybenzoate decarbamoylsaxitoxin analogues can render decarbamoylsaxitoxin and decarbamoylneosaxitoxin. Obtaining decarbamoylgonyautoxins was not suitable resorting to decarbamoylgonyautoxin type hydroxybenzoate analogues due to the prolonged reaction times required for complete hydrolysis and their instability at high pH. Hydrolysis of sulphated-benzoate analogues was best suited for obtaining decarbamoylgonyautoxins due to the very rapid hydrolysis time required. © 2010 Elsevier Ltd.

Vale P.,Instituto Nacional dos Recursos Biologicos
Toxicon | Year: 2010

Bivalve metabolites of saxitoxin analogues, not present in microalgae, were recently described as an important toxin fraction in mussels contaminated by Alexandrium tamarense. These possess very low fluorescence, and require mass spectrometry detection. HILIC-MS was implemented to look for these metabolites in bivalves contaminated during Gymnodinium catenatum blooms at the Portuguese coast. The presence of M1 was tentatively identified in several bivalves, ranging from estuarine (Mytilus galloprovinciallis, Cerastoderma edule and Ruditapes decussatus) to oceanic habitat (Donax trunculus and Ensis spp.). It was hypothesized that M1 could contribute to an important fraction of the profile of STX analogues. M1 was more abundant in estuarine bivalves that retain longer PSP toxins, in the following order: mussels > cockles > clams. These data highlight that the study by fluorimetry alone of the carbamoyl, N-sulfocarbamoyl, and decarbamoyl families is manifestly insufficient to fully understand toxin dynamics in bivalves feeding on G. catenatum without a proper study of hydroxybenzoate and hydroxylated M-toxins. © 2009 Elsevier Ltd. All rights reserved.

At Aveiro lagoon (Portuguese northwest coast) bivalve contamination with diarrhoetic shellfish poisoning toxins (DSTs), okadaic acid (OA) and dinophysistoxin-2 (DTX2), is a recurrent annual phenomenon seriously affecting seafood safety. The influence of meteorological parameters was studied to understand accumulation of DSTs in mussels, related to the blooming of the causative toxic microalgae, belonging to genus Dinophysis.Two simplified models were useful in predicting the accumulation of DSTs in blue mussels from this lagoon. Either the May river drainage or the rainfall accumulated from January through May could adequately predict the severity of OA accumulated from predation upon Dinophysis acuminata during June/July. In both cases a linear relationship was obtained, with correlation coefficients of 0.85 or greater.Winds with a west direction favour coastal concentration of Dinophysis acuta in Aveiro region. Both OA and DTX2 contamination increased exponentially in September/October with the cumulative number of days with W-wind orientation in the preceding August (correlation coefficients greater than 0.92). This relationship was attributed to the quadratic effect of wind stress on surface currents.August is a transitional month, when the continental runoff effect upon Dinophysis acuminata can still be observed and Dinophysis acuta advection may be promoted by westerly winds occurring in July. The frequency of periods with northerly winds in July can halt accumulation of toxins derived from Dinophysis acuta. © 2011 Elsevier Ltd.

Santos C.,Instituto Nacional dos Recursos Biologicos | Gomes A.,Instituto Nacional dos Recursos Biologicos | Roseiro L.C.,Instituto Nacional dos Recursos Biologicos
Food and Chemical Toxicology | Year: 2011

Meat and meat products safety is, nowadays, a priority quality requirement with chemical hazards having a great impact. Amongst the residues and contaminants, polycyclic aromatic hydrocarbons (PAHs) can be of particular concern, namely in those products having direct smoking during processing. In order to investigate the contamination levels in traditional dry fermented sausages manufactured in Alentejo (South of Portugal), 66 samples were collected from regional producers. PAH8 represented less than 0.5% of the total contamination profile, with benzo[a]anthracene and chrysene being the most concentrated compounds (maximum contents of 7.53 and 8.9μgkg -1), irrespective of the product type analysed. Benzo[a]pyrene content varied between 0.21 and 1.00μgkg -1, with only one sample showing this maximum content. Blood sausages were potentially more risky, since total PAH8 contents were generally higher and because its presence in inner parts were significantly superior than that found in casings, comparatively to meat counterparts, which expressed superior benzo[a]pyrene toxic equivalents. © 2011 Elsevier Ltd.

Vale P.,Instituto Nacional dos Recursos Biologicos
Comparative Biochemistry and Physiology - C Toxicology and Pharmacology | Year: 2010

The presence of 7-O-acyl okadaic acid (OA) esters was studied by LC-MS in the digestive glands of blue mussel (Mytilus galloprovincialis) and common cockle (Cerastoderma edule) from Albufeira lagoon, located 20 km south of Lisbon. The profile of free and total fatty acids (FA) was analysed using a similar LC separation with a reversed phase C8 column and mass spectrometry detection. In mussel the free FA profile was reflected in the FA esterified to OA, being palmitic acid for instance the most abundant in both cases. In cockle, 7-O-acyl esters with palmitic acid were almost absent and esters with a C16:0 isomer were dominant, followed by esters with C15:1 and C15:0. The cockle free FA profile was similar to mussel, and in accordance with literature findings in bivalves. After hydrolysis, a major difference in the FA profile occurred in both species, presenting a high percentage of a C16:0 isomer. The isomer found in general lipids and bound to OA seemed to be related, presenting similar relative retention times (RRT) to C16:0, differing from expected RRT of monomethyl-branched isomers (iso- or anteiso-). A tentative identification was made with the multimethyl-branched isoprenoid, 4,8,12-trimethyltridecanoic acid (TMTD). TMTD is a product of phytol degradation. This was also suspected when the proportion of this compound in relation to palmitic acid was reduced in vivo in mussels fed a chlorophyll-free diet. Extensive esterification of OA by, among others, phytol-degrading bacteria is discussed as a plausible hypothesis in cockle, but not in mussel, due to the relatively high specific proportion of odd-numbered and branched FA. © 2009 Elsevier Inc. All rights reserved.

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