Aplicação da cromatografia de partição gás-líquido no estudo da ecologia trófica da fase adulta de lampreia-marinha (Petromyzon marinus L.)

Apesar da relevância biológica e do impacto económico associado à sua exploração comercial, a informação existente acerca dos hábitos alimentares na fase marinha parasitária da lampreia-marinha é muito limitada e poucos estudos têm examinado a organização metabólica desta espécie. A inactividade alimentar associada à migração reprodutora confere algumas garantias de que a composição em ácidos gordos dos lípidos totais e/ou dos triacilgliceróis do músculo reflecte, até certo ponto, a dieta destes animais na fase marinha e, consequentemente, o grupo de hospedeiros preferenciais. O presente estudo foi conduzido com o intuito de caracterizar qualitativamente os ácidos gordos dos lípidos totais do músculo de 45 animais capturados durante a migração reprodutora nas bacias hidrográficas do Minho, Tejo e Guadiana e de avaliar se a existência de eventuais diferenças na composição em ácidos gordos poderiam indiciar dietas distintas, porventura características das zonas geográficas onde os animais foram capturados. Os lípidos totais do músculo foram extraídos pelo método de Folch et al. (1957). Os ésteres metílicos dos ácidos gordos dos lípidos totais foram preparados pelo método de Morrison & Smith (1964). De seguida, os ésteres metílicos dos ácidos gordos foram analisados num cromatógrafo Hewlett Packard HP 6890 Series GC System, com software HPChem (2002), equipado com injector split-splitless e detector de ionização por chama (FID). Foi utilizada uma coluna capilar Omegawax 320 (30 m de comprimento x 0.32 mm de diâmetro interno, 0.25 m de espessura de filme, da Supelco). A fase móvel foi hélio com um fluxo de 1,2 ml/min. A temperatura do injector e do detector foi de 250C e a temperatura do forno foi mantida a 200C. A razão de split foi de 100:1 A corrida foi feita a 200C sem rampa de temperatura durante 55 minutos. Os ésteres metílicos dos ácidos gordos foram identificados recorrendo à comparação dos tempos de retenção obtidos com os tempos de retenção dos ésteres metílicos dos ácidos gordos de uma mistura padrão de referência (Supelco). Cada éster metílico foi expresso em percentagem do total de ésteres metílicos identificados. Foi utilizada uma análise discriminante múltipla para avaliar o nível de segregação das amostras pertencentes às três bacias, tendo por base a composição em ácidos gordos dos lípidos totais do músculo. Verificou-se que os ácidos gordos mais abundantes no músculo das lampreias estudadas foram os ácidos gordos monoinsaturados, seguidos dos ácidos gordos saturados e por último dos ácidos gordos poliinsaturados. Constatou-se a existência de segregação das populações a nível geográfico, com uma separação mais evidente para a bacia hidrográfica do Tejo, sendo que os ácidos gordos que contribuíram para este resultado foram o ácido merístico (C14:0), o ácido eicosenóico (C20:1ω9), o ácido erúcico (C22:1ω9) e o ácido nervónico (C24:1ω9), estes três últimos pertencentes à família ω9. Verificando-se a hipótese destes ácidos gordos serem originários dos hospedeiros seleccionados pelas lampreias, então poder-se-á concluir que a sua proveniência geográfica promove diferenças na ecologia trófica desta espécie durante a fase marinha parasitária

Adsorption of marine phycotoxin okadaic acid on a covalent organic framework

Phycotoxins, compounds produced by some marine microalgal species, can reach high concentrations in the sea when a massive proliferation occurs, the so-called harmful algal bloom. These compounds are especially dangerous to human health when concentrated in the digestive glands of seafood. In order to generate an early warning system to alert for approaching toxic outbreaks, it is very important to improve monitoring methods of phycotoxins in aquatic ecosystems. Solid-phase adsorption toxin tracking devices reported thus far based on polymeric resins have not been able to provide an efficient harmful algal bloom prediction system due to their low adsorption capabilities. In this work, a water-stable covalent organic framework (COF) was evaluated as adsorbent for the hydrophobic toxin okadaic acid, one of the most relevant marine toxins and the parental compound of the most common group of toxins responsible for the diarrhetic shellfish poisoning. Adsorption kinetics of okadaic acid onto the COF in seawater showed that equilibrium concentration was reached in only 60 min, with a maximum experimental adsorption of 61 mg g1. Desorption of okadaic acid from the COF was successful with both 70% ethanol and acetonitrile as solvent, and the COF material could be reused with minor losses in adsorption capacity for three cycles. The results demonstrate that COF materials are promising candidates for solid-phase adsorption in water monitoring devices.This article is a result of the project Nanotechnology Based Functional Solutions (NORTE-01-0145-FEDER-000019), supported by Norte Portugal Regional Operational Programme (NORTE2020) under the PORTUGAL 2020 Partnership Agreement through the European Regional Development Fund (ERDF). This project has received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement no. 600375.info:eu-repo/semantics/publishedVersio

Effect of in vitro gastrointestinal digestion on the total phenolic contents and antioxidant activity of wild Mediterranean edible plant extracts

The recent interest in wild edible plants is associated with their health benefits, which are mainly due to their richness in antioxidant compounds, particularly phenolics. Nevertheless, some of these compounds are metabolized after ingestion, being transformed into metabolites frequently with lower antioxidant activity. The aim of the present study was to evaluate the influence of the digestive process on the total phenolic contents and antioxidant activity of extracts from four wild edible plants used in the Mediterranean diet (Beta maritima L., Plantago major L., Oxalis pes-caprae L. and Scolymus hispanicus L.). HPLC-DAD analysis revealed that S. hispanicus is characterized by the presence of caffeoylquinic acids, dicaffeoylquinic acids and flavonol derivatives, P. major by high amounts of verbascoside, B. maritima possesses 2,4-dihydroxybenzoic acid, 5-O-caffeoylquinic acid, quercetin derivatives and kaempferol-3-O-rutinoside, and O. pes-caprae extract contains hydroxycinnamic acids and flavone derivatives. Total phenolic contents were determined by Folin-Ciocalteu assay, and antioxidant activity by the ABTS, DPPH, ORAC and FRAP assays. Phenolic contents of P. major and S. hispanicus extracts were not affected by digestion, but they significantly decreased in B. maritima after both phases of digestion process and in O. pes-caprae after the gastric phase. The antioxidant activity results varied with the extract and the method used to evaluate the activity. Results showed that P. major extract has the highest total phenolic contents and antioxidant activity, with considerable values even after digestion, reinforcing the health benefits of this species.European Union (FEDER funds through COMPETE)European Union (EU)European Union (FEDER)European Union (EU)Programa de Cooperacion Interreg V-A Espana - Portugal (POCTEP) 2014-2020 [0377_IBERPHENOL_6_E]project INTERREG - MD. Net: When Brand Meets PeopleFCT Portuguese Foundation for Science and Technolog

Trophic Relationships and Habitat Preferences of Delphinids from the Southeastern Brazilian Coast Determined by Carbon and Nitrogen Stable Isotope Composition

To investigate the foraging habitats of delphinids in southeastern Brazil, we analyzed stable carbon (δ13C) and nitrogen (δ15N) isotopes in muscle samples of the following 10 delphinid species: Sotalia guianensis, Stenella frontalis, Tursiops truncatus, Steno bredanensis, Pseudorca crassidens, Delphinus sp., Lagenodelphis hosei, Stenella attenuata, Stenella longirostris and Grampus griseus. We also compared the δ13C and δ15N values among four populations of S. guianensis. Variation in carbon isotope results from coast to ocean indicated that there was a significant decrease in δ13C values from estuarine dolphins to oceanic species. S. guianensis from Guanabara Bay had the highest mean δ13C value, while oceanic species showed significantly lower δ13C values. The highest δ15N values were observed for P. crassidens and T. truncatus, suggesting that these species occupy the highest trophic position among the delphinids studied here. The oceanic species S. attenuata, G. griseus and L. hosei had the lowest δ15N values. Stable isotope analysis showed that the three populations of S. guianensis in coastal bays had different δ13C values, but similar δ15N results. Guiana dolphins from Sepetiba and Ilha Grande bays had different foraging habitat, with specimens from Ilha Grande showing more negative δ13C values. This study provides further information on the feeding ecology of delphinids occurring in southeastern Brazil, with evidence of distinctive foraging habitats and the occupation of different ecological niches by these species in the study area.Peer reviewe

Comparison of the fatty acid profile of muscle neutral lipids and phospholipids of up-river anadromous sea lamprey (Petromyzon marinus L.) (Agnatha) from three Portuguese river basins

SUMMARY Composition of fatty acid profile of muscle neutral lipids (NL) and phospholipids (PL) of sea lamprey that enter the Portuguese rivers Minho, Tagus and Guadiana during their non-trophic spawning migration was analyzed. The fatty acid distribution in NL was similar and revealed that monounsaturated fatty acids (MUFA) were the most representative, followed by saturated fatty acids (SFA) and finally by polyunsaturated fatty acids (PUFA). Monoenic 16:1 and 18:19 formed a considerable percentage of total fatty acids, followed by SFA 14:0 and 16:0. EPA and DHA were the dominant PUFA fatty acids. Lampreys from Tagus river basin presented the highest percentages of fatty acids (P≤0.001). The fatty acid that contributed for the discrimination of the three river basins was 18:17. The fatty acid composition of PL fraction showed that animals from Minho river basin had a different profile characterized by low PUFA percentage when compared with lampreys from Tagus and Guadiana river basins. Monoenic acids were primarily represented by 16:1 and 18:19. A high level of 16:0 characterized the SFA followed by 14:0. Among PUFA, DHA was the most representative fatty acid. The fatty acids that contributed for the separation of the three river basins were 16:0, 18:43 and 24:19

Comparison of the fatty acid profile of muscle neutral lipids and phospholipids of up-river anadromous sea lamprey (Petromyzon marinus L.) from three Portuguese river basins.

Composition of fatty acid profile of muscle neutral lipids (NL) and phospholipids (PL) of sea lamprey that enter the Portuguese rivers Minho, Tagus and Guadiana during their non-trophic spawning migration was analysed. The fatty acid profile exhibited differences in the percentage among NL and PL and between river basins. Similarities were found in the fatty acid profile of NL. Monounsaturated fatty acids (MUFA) were the most representative, followed by saturated fatty acids (SFA) and finally by polyunsaturated fatty acids (PUFA). Monoenic 16:1 and 18:1ω9 formed a considerable percentage of total fatty acids, followed by SFA 14:0 and 16:0. EPA and DHA were the dominant PUFA fatty acids. In terms of NL, the fatty acid that contributed for the discrimination between the three river basins was 18:1ω7. Individuals from the Minho river basin exhibited a different fatty acid profile of PL characterised by a low PUFA percentage when compared with lampreys from the Tagus and Guadiana river basins. Muscle PL fraction showed that the two monoenes, 16:1 and 18:1ω9, occurred at high percentage, followed by 16:0 and 14:0 (SFA). Among PUFA, DHA was the most representative fatty acid. The fatty acids that contributed to the separation between the three river basins were 16:0, 18:4ω3 and 24:1ω9. Although the results point in the direction of a possible difference between the fatty acid composition of the NL and PL fractions in the muscle samples from the three river basins, further studies, especially in tissues where fatty acid composition will be less sensitive to diet and environmental factors, are necessary to confirm this hypothesis

Particle transport and deposition in porous structures: effects of particle properties, porosity and Reynolds number

Since experiments are expensive and often difficult to perform reliable computational fluid dynamics (CFD) models save time and money when applied to transport and deposition of aerosol particles. In this work, we simulate particle transport and deposition in porous structures with different porosity. The resulting air-flow patterns as well as particle transport and deposition are analyzed for different inlet flows and particle with different properties (i.e., density and diameter). We compute particle trajectories and the deposition for different conditions. In addition, the loss of permeability due to deposition is evaluated

Permeability-porosity relationship assessment by 2-D numerical simulations

An accurate evaluation of the permeability of a porous structure is critical for predicting fluid flow rates. In this study, we report the results of two-dimensional simulations of creeping flow through porous structures with porosities between 0.2 and 0.99. Our numerical results demonstrate that in this range, permeability is an exponential function of the porosity. This result is found to be in good agreement with experimental data. In addition, we compare our simulation results with some permeability-porosity relationship available in literature. We found that Carman–Kozeny’s correlation agrees very well with our results for porosities up to 0.87 and Koponen et al.’s relationship holds well for porosities higher than 0.95. Based on the results obtained in this study, a new permeability-porosity relationship is presented, for the model system used