Unidade de Investigação - MARE – Marine and Environmental Sciences Centre
Permanent URI for this community
Browse
Browsing Unidade de Investigação - MARE – Marine and Environmental Sciences Centre by Issue Date
Now showing 1 - 10 of 495
Results Per Page
Sort Options
- Aumento da IL-6 sérica pós-queimadura e falência multiorgânicaPublication . Cardoso, Susana; Cabral, Luis; Cruzeiro, Celso; Garção, Fátima; Rosa, Manuel SantosIntrodução: Quando comprometida a primeira linha de defesa, como acontece no contexto de queimadura, o sistema imunitário encontra-se numa situação muito particular. É induzida uma cascata pró-inflamatória acentuada. Têm sido registadas alterações ao nível do funcionamento dos macrófagos [1] e alterações das citocinas Th1/Th2 mas é difícil estabelecer situações-padrão e indicadores de prognóstico [2,3]. Fenómenos de sepsis e falência multiorgânica são habitualmente as causas de morte que advêm do descontrolo imunitário [4]. Material e Métodos: Para o presente estudo prospectivo, foram seleccionados 20 doentes, de idades compreendidas entre os 25 e 50 anos, com queimaduras de segundo e terceiro graus e uma área queimada (TBSA) de 20% a 60%. Todos os indivíduos foram sujeitos a balneoterapia e enxertos. Nenhum dos doentes apresentava anomalias ou problemas crónicos antes do acidente. Quantificaram-se as interleucinas IL-6, IL-8, IL-10 e IL-12, células NK e subpopulações linfocitárias. A monitorização iniciou-se o mais precoce possível após a admissão hospitalar, repetindo-se três dias depois e com intervalos de uma semana. Resultados: Verifica-se uma desregulação da imunidade celular e alterações das citocinas. Entre os não-sobreviventes foram registados valores mais reduzidos de células NK e células T helper e um ratio CD4/CD8 mais elevado. Ainda nestes doentes, o acentuado aumento da IL-6 especialmente aquando da admissão (p<0,02), parece causar uma inflamação persistente e excessiva que pode conduzir à falência multiorgânica, por impedimento da reconstrução tecidular. Conclusões: Os processos responsáveis pelo fracasso da resposta imunitária na queimadura, são uma ampla reacção inflamatória mediada pela produção excessiva de IL-6, parcialmente relacionada com a área queimada e uma depressão da imunidade celular. Este parâmetro (IL-6) pode ser um forte indicador de prognóstico e vir a ser um alvo terapêutico de imunomodulação. Por análise de toda a variação registada ao nível das interleucinas analisadas, não existe evidência de comprometimento Th1.
- Sandy beach macrofaunal communities on the western coast of Portugal – Is there a steady structure under similar exposed conditions?Publication . Gonçalves, Sílvia C.; Anastácio, Pedro M.; Pardal, Miguel A.; Cardoso, Patrícia G.; Ferreira, Susana M.; Marques, João C.; Gonçalves, Sílvia; Ferreira, SusanaThe structure of macrofaunal communities at two similar exposed sandy beaches on the western coast of Portugal was monitored for approximately 18 months by sampling all the beach area, from the shoreline to the base of the dunes. The beaches' physical environment, as well as community density and composition, seasonal variations and the potential relationships between biological data and environmental parameters were studied. The two beaches had similar exposure to wave action, but differed in terms of sediment grain size, extent of the intertidal area, sediment moisture content and, especially, in the potential food availability in the form of allochthonous debris. Differences were observed with regard to the communities' structure, namely regarding composition and relative contribution of the dominant species. Seasonality, especially temperature variations, and the interaction between seasons and the beach zones (supralittoral vs. intertidal) also had a strong influence on communities: controlling dominant species' density and the horizontal distribution of the dominant species, and promoting a differential utilization of the beach by several resident macrofaunal animals. The present study allows the identification of key species in exposed sandy beaches of western Portugal and demonstrates that a steady community structure does not persist in the similarly exposed conditions observed, which may be mainly a response to distinct detritus subsidies, combined with differences in sediment grain size, sediment moisture content and extent of the intertidal area.
- Spatio-temporal structure of diatom assemblages in a temperate estuary. A STATICO analysisPublication . Mendes, Susana; Fernández-Gómez, Maria José; Resende, Paula; Pereira, Mário Jorge; Galindo-Villardón, Maria Purificación; Azeiteiro, Ulisses MirandaThis study examines the spatio-temporal structure of diatom assemblages in a temperate estuary (Ria de Aveiro, Western Portugal). Eighteen monthly surveys were conducted, from January 2002 to June 2003, at three sampling sites (at both high and low tide) along the estuarine salinity gradient. The relationship of diatom assemblages and environmental variables was analysed using the STATICO method, which has been designed for the simultaneous analysis of paired ecological tables. This method allowed examination of the stable part of the environment-diatom relationship, and also the variations of this relationship through time. The interstructure factor map showed that the relationship between the 11 environmental variables and the abundance of the 231 diatom species considered was strongest in the months May and September 2002 and January, February and May 2003. The stable part of the species-environment relationships mainly consisted of a combined phosphate, chlorophyll a and salinity gradient linked to a freshwater-marine species gradient. A more pronounced gradient was observed in January, February and May 2003. Diatom assemblages showed clear longitudinal patterns due to the presence of both marine and freshwater components. May and September 2002 had the least structured gradients with marine-estuarine species appearing in the freshwater side of the gradient. The most complete gradient in February 2003 could be considered, in terms of bio-ecological categories, as the most structured period of the year, with a combination of strong marine influence in the lower zone and freshwater influence in the upper. The best-structured gradients were during periods of a diatom bloom. Stable diatom assemblages (with a strong structure and a good fit between the diatoms and environment) are described and characterized. This study shows the efficiency of the STATICO analysis. The inclusion of space-time data analysis tools in ecological studies may therefore improve the knowledge of the dynamics of species-environmental assemblages.
- Developmental Toxicity of Endocrine Disrupters Bisphenol A and Vinclozolin in a Terrestrial IsopodPublication . Lemos M.F.L.; van Gestel, C. A. M.; Soares, A. M. V. M.Studies of the effects of endocrine-disrupting compounds (EDCs) on invertebrates are still largely underrepresented. This work aims to fill this gap by assessing the effects of bisphenol A (BPA) and vinclozolin (Vz) on the terrestrial isopod Porcellio scaber (common rough woodlouse). Male adult and sexually undifferentiated juvenile woodlice were exposed to the toxicants. Effects on molting regime and growth were investigated independently for males and female woodlice after sexual differentiation. Both chemicals elicited developmental toxicity to P. scaber by causing overall decreased growth. Nevertheless, BPA induced molting, whereas Vz delayed it. Although the LC 50 values for juvenile and adult survival were fairly similar, juvenile woodlice showed an increased chronic sensitivity to both chemicals, and female woodlice were most the sensitive to BPA. We recommend the use of adults, juveniles, female, and male woodlice, as well as a large range of toxicant concentrations, to provide valuable information regarding differential dose responses, effects, and threshold values for EDCs.
- Tryptophan Depletion and Formation of α-Aminoadipic and γ-Glutamic Semialdehydes in Porcine Burger Patties with Added Phenolic-Rich Fruit ExtractsPublication . Ganhão, Rui; Morcuende, David; Estévez, MarioThe effect of added fruit extracts on the oxidation of muscle proteins in porcine burger patties subjected to cooking and chill storage was studied. Extracts from arbutus berries (Arbutus unedo L., AU), common hawthorns (Crataegus monogyna L., CM), dog roses (Rosa canina L., RC), and elmleaf blackberries (Rubus ulmifolius Schott, RU) were prepared, characterized, added to burger patties (3% of total weight), and evaluated as inhibitors of protein oxidation. Negative (no added extract, C) and positive control (added quercetin, 230 mg/kg, Q) groups were also included in the design. Protein oxidation was assessed by means of tryptophan loss using fluorescence spectroscopy (FS) and formation of the specific protein carbonyls αaminoadipic (AAS) and y-glutamic semialdehyde (GGS) using liquid chromatography and mass spectroscopy (LC-MS). Both advanced methodologies (FS and LC-MS) were found to be reliable and specific protein oxidation measurements that allow us to gain chemical insight into protein oxidation. The mechanisms likely involved In the oxidative reactions affecting proteins during cooking and storage of burger patties are profusely discussed. Phenolic-rich fruit extracts protected tryptophan residues against oxidation and Inhibited the formation of both semialdehydes In burger patties during cooking and subsequent chill storage. In general, RC, RU, and AU were the most effective inhibitors of protein oxidation, with this effect being more intense than that of pure polyphenols like quercetin. These fruit extracts could be considered functional ingredients as their antioxidant actions contribute to the enhancement of the nutritional value of the meat products.
- Production of human milk fat substitutes enriched in omega-3 polyunsaturated fatty acids using immobilized commercial lipases and Candida parapsilosis lipase/acyltransferasePublication . Tecelão, Carla; Silva, Joana; Dubreucq, Eric; Ribeiro, Maria H.; Ferreira-Dias, SuzanaIn human milk fat (HMF), palmitic acid (20-30%), the major saturated fatty acid, is mostly esterified at the sn-2 position of triacylglycerols, while unsaturated fatty acids are at the sn-1,3 positions, conversely to that occurring in vegetable oils. This study aims at the production of HMF substitutes by enzyme-catalyzed interesterification of tripalmitin with (i) oleic acid (system I) or (ii) omega-3 polyunsaturated fatty acids (omega-3 PUFA) (system II) in solvent-free media. Interesterification activity and batch operational stability of commercial immobilized lipases from Rhizomucor miehei (Lipozyme RM IM), Thermomyces lanuginosa (Lipozyme TL IM) and Candida antarctica (Novozym 435) from Novozymes, DK, and Candida parapsilosis lipase/acyltransferase immobilized on Accurel MP 1000 were evaluated. After 24-h reaction at 60 °C, molar incorporation of oleic acid was about 27% for all the commercial lipases tested and 9% with C. parapsilosis enzyme. Concerning omega-3 PUFA, the highest incorporations were observed with Novozym 435 (21.6%) and Lipozyme RM IM (20%), in contrast with C. parapsilosis enzyme (8.5%) and Lipozyme TL IM (8.2%). In system I, Lipozyme RM IM maintained its activity for 10 repeated 23-h batches while for Lipozyme TL IM, Novozym 435 and C. parapsilosis enzyme, linear (half-life time, t1/2 = 154 h), series-type (t1/2 = 253 h) and first-order (t1/2 = 34.5 h) deactivations were respectively observed. In system II, Lipozyme RM IM showed linear deactivation (t1/2 = 276 h), while Novozym 435 (t1/2 = 322 h) and C. parapsilosis enzyme (t1/2 = 127 h), presented series-type deactivation. Both activity and stability of the biocatalysts depended on the acyl donor used.
- The status of farmed fish hearts: an alert to improve health and production in three Mediterranean speciesPublication . Pombo, Ana; Blasco, Manuel; Climent, VicenteThe heart ventricles of farmed gilthead seabream (Sparus aurata), European seabass (Dicentrarchus labrax) and Senegalese sole (Solea senegalensis) have been examined and we compared them to the corresponding fish from wild populations. These results can help to understand the differences in farmed fish hearts and in the myocardial structure that this condition of growth can produce. Several parameters were measured in the two groups. Numerical comparisons included heart mass, cardiac and ventricular index, ventricle height:width ratio, width and alignment of bulbus arteriosus, ventricular angles and compacta thickness. We confirm that the normal shape of wild fish hearts can be modified as a result from the adaptation to different environments. These changes can modify the structure of myocardium and compromise the cardiac function in farmed species. The ventricle of farmed fish present differences in shape, were misaligned, rounder, with a wider bulbus and thinner compact layer. Further studies are necessary to reveal functional significance and possible causes of these abnormal hearts and improve the cardiac welfare of Mediterranean species in culture as a way of ensuring a level of production compatible with economic benefits.
- Bioaccumulation and Elimination of Waterborne Mercury in the Midge Larvae, Chironomus riparius Meigen (Diptera: Chironomidae)Publication . Azevedo-Pereira, Henrique M. V. S.; Abreu, Sizenando N.; Lemos, Marco F.L.; Soares, Amadeu M. V. M.Here, mercury kinetics and behavioural effects in the midge larvae under a water-only exposure were assessed. Uptake and elimination of waterborne mercury were described by using a one-compartment kinetic model. Results show that midges were able to readily accumulate the heavy metal (BCF = 450), presenting a fast uptake, up to 13.1 lg Hg g of animal-1 at the end of the exposure period. Elimination was slow, with c.a. 39 % of the mercury in larvae being depurated after 48 h in clean medium. Behaviour did not present differences upon exposure or elimination, but a trend to increase ventilation was noticed during the exposure period.
- Antioxidant and antimicrobial potential of the Bifurcaria bifurcata epiphytic bacteriaPublication . Horta, André; Pinteus, Susete; Alves, Celso; Fino, Nádia; Silva, Joana; Fernandez, Sara; Rodrigues, Américo; Pedrosa, RuiSurface-associated marine bacteria are an interesting source of new secondary metabolites. The aim of this study was the isolation and identification of epiphytic bacteria from the marine brown alga, Bifurcaria bifurcata, and the evaluation of the antioxidant and antimicrobial activity of bacteria extracts. The identification of epiphytic bacteria was determined by 16S rRNA gene sequencing. Bacteria extracts were obtained with methanol and dichloromethane (1:1) extraction. The antioxidant activity of extracts was performed by quantification of total phenolic content (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and oxygen radical absorbance capacity (ORAC). Antimicrobial activities were evaluated against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, Salmonella enteritidis, Staphylococcus aureus, Saccharomyces cerevisiae and Candida albicans. A total of 39 Bifurcaria bifurcata-associated bacteria were isolated and 33 were identified as Vibrio sp. (48.72%), Alteromonas sp. (12.82%), Shewanella sp. (12.26%), Serratia sp. (2.56%), Citricoccus sp. (2.56%), Cellulophaga sp. (2.56%), Ruegeria sp. (2.56%) and Staphylococcus sp. (2.56%). Six (15.38%) of the 39 bacteria Bifurcaria bifurcata-associated bacteria presented less than a 90% Basic Local Alignment Search Tool (BLAST) match, and some of those could be new. The highest antioxidant activity and antimicrobial activity (against B. subtilis) was exhibited by strain 16 (Shewanella sp.). Several strains also presented high antimicrobial activity against S. aureus, mainly belonging to Alteromonas sp. and Vibrio sp. There were no positive results against fungi and Gram-negative bacteria. Bifurcaria bifurcata epiphytic bacteria were revealed to be excellent sources of natural antioxidant and antimicrobial compounds.
- Effects of different drying conditions on the rehydration ratio and water holding capacity properties in three different species of algae Ulva lactuca, Codium vermilara and Codium tomentosumPublication . Rodrigues, Sidónio; Afonso, Clélia; Mouga, Teresa; Nunes, PauloOver the last years, algae have been increasingly used in Human food due their rich chemical and nutritional composition, particularly the high supply of essential nutrients to the human body such as protein and dietary fiber. Dietary fiber can be divided into two different types: soluble and insoluble. The characteristics of soluble dietary fiber are related to some physical and chemical properties such as rehydration ratio and water holding capacity and are important in assigning the functional and organoleptic properties and in preventing some human pathologies such as cardiovascular disease and obesity. The present study aimed to investigate the influence of different drying conditions on the rehydration ratio and water holding capacity of three green algae, Codium vermilara, Codium tomentosum and Ulva lactuca. The methods used for the determination of water retention capacity and rehydration ratio were similar to those used in previous studies (Susuki, T. et al., 1996). The algae were processed in a tray dryer and the drying conditions were: Temperature: 30ºC and 40ºC; Relative Humidity: 28%47% ; air velocity 1,9 m/s. In this work, it was concluded that higher drying temperature conditions originate lower rehydration ratio and consequent lower water holding capacity possibly due to a higher physical damage in the algae tissues. It was also observed that both Codium species have higher values for these two parameters than Ulva lactuca, under the same rehydration conditions.