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- 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.
- 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.
- The biotechnological and seafood potential of Stichopus regalisPublication . Santos, Rita; Dias, Simaura; Pinteus, Susete; Silva, Joana; Alves, Celso; Tecelão, Carla; Pombo, Ana; Pedrosa, RuiSea cucumbers are highly used not only for the production of the bêche-de-mer, but also recent studies have been showing the high potential of these marine invertebrates on the pharmaceutical industry, as they are rich in bioactive compounds with important functions. Stichopus regalis extracts (1 mg∙mL−1) were used in antioxidant, antimicrobial and antitumor assays. The lipid profile was also evaluated. No significant antioxidant activity was detected in both methanolic and dichloromethane extracts. The methanolic fraction showed the highest antimicrobial potential against Candida albicans with an IC50 of 475.4 μg∙mL−1. In the antitumor assays, the dichloromethane fraction showed a high potential for both cell lines, as revealed by the MTT method. The total fat content was 3.63% ± 0.11% and the fatty acid profile revealed the highest amount in C16:0 (9.43% ± 0.77%), C18:0 (12.43% ± 0.83%), C18:1 ω7 (5.63% ± 0.33%), EPA (12.49% ± 0.15%), DHA (7.35% ± 0.02%), ARA (19.29% ± 0.14%) and a ω3/ω6 ratio of 1.078. These findings led us to suggest the potential use of S. regalis as a new source of bioactive compounds with pharmacological potential and its nutritional benefits for human health.
- Optimising sealed transports of small ornamental fishPublication . Silva, Rui E.; Morais, Hugo A.; Rodrigues, Nuno V.; Reis, Tiago; Correia, João P.This paper reports on simulated long-term transports of small ornamental fish inside sealed containers. The species involved were Diplodus sargus, Gobius paganellus, Gobiusculus flavescens, Lepadogaster lepadogaster, and Lipophrys pholis. The objective of such simulations was to determine the maximum bioload that it is possible to move inside a sealed container, while ensuring 100% survivorship, ultimately resulting in financial savings for the end-receiver. Transports were simulated over 24, 48 and 72 hours, with increasing animal bioloads per bag. Fifty percent of the trials were performed with “regular” saltwater while the other half involved seawater buffered with Amquel®, sodium carbonate and sodium bicarbonate, with the objective of keeping ammonia low and pH similar to initial baseline values. At the end of each trial, temperature, dissolved oxygen, pH and ammonia were analysed and survival rates determined. L. lepadogaster endured the highest bioloads and displayed 100% survivorship (i.e. up to 30 g/L), which is not surprising given the intertidal nature of this species. D. sargus exhibited mortalities with bioloads as low as 3.23 g/L, which echoes its predominantly pelagic nature and relatively lesser ability to endure confinement. The three remaining species showed varying degrees of tolerance to increasing bioloads in transport: L. pholis, also an intertidal species, tolerated up to 20 g/L over 72 hours, while G. paganellus tolerated up to 7 g/L over 72 hours, and G. flavescens (a predominantly pelagic species) could tolerate no more than 6 g/L up to 72 hours.
- Biochemical performance of native and introduced clam species living in sympatry: The role of elements accumulation and partitioningPublication . Velez, Cátia; Leandro, Sérgio; Figueira, Etelvina; Soares, Amadeu M.V.M.; Freitas, RosaThe present study reports metal and arsenic contamination in sediments, as well as element accumulation and partitioning in native (Ruditapes decussatus and Venerupis corrugata) and introduced (Ruditapes philippinarum) clam species living in sympatry at the Obidos lagoon (Portugal). The biochemical performance and the human health risks derived from the consumption of these species are also discussed. The results obtained showed that R. decussatus was the most abundant species in all the sampling sites, revealing that the introduced clam has not yet supplanted the native species. The concentration of elements was higher in areas with higher Total Organic Matter (TOM) and fines content, being Chromium (Cr), Copper (Cu) and Lead (Pb) the most abundant metals. Clams from these areas showed the highest concentration of elements but the lowest bioaccumulation levels. Furthermore, except for As, higher concentration of elements was found in clams insoluble fraction, the less toxic fraction to the organisms. Due to the low contamination levels and because elements, except As, were mainly allocated to the insoluble fraction, clams presented similar biochemical parameters among distinct areas, with no significant oxidative stress induced. Furthermore, clams from the Obidos lagoon represent a low health risk to human consumption since, except for As, their contamination levels were below the maximum permissible limits defined by international organizations.
- Antitumor and antimicrobial potential of bromoditerpenes isolated from the red alga, Sphaerococcus coronopifoliusPublication . Rodrigues, Daniel; Alves, Celso; Horta, André; Pinteus, Susete; Silva, Joana; Culioli, Gérald; Thomas, Olivier P.; Pedrosa, RuiCancer and infectious diseases continue to be a major public health problem, and new drugs are necessary. As marine organisms are well known to provide a wide range of original compounds, the aim of this study was to investigate the bioactivity of the main constituents of the cosmopolitan red alga, Sphaerococcus coronopifolius. The structure of several bromoditerpenes was determined by extensive spectroscopic analysis and comparison with literature data. Five molecules were isolated and characterized which include a new brominated diterpene belonging to the rare dactylomelane family and named sphaerodactylomelol (1), along with four already known sphaerane bromoditerpenes (2–5). Antitumor activity was assessed by cytotoxicity and anti-proliferative assays on an in vitro model of human hepatocellular carcinoma (HepG-2 cells). Antimicrobial activity was evaluated against four pathogenic microorganisms: Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Candida albicans. Compound 4 exhibited the highest antimicrobial activity against S. aureus (IC50 6.35 μM) and compound 5 the highest anti-proliferative activity on HepG-2 cells (IC50 42.9 μM). The new diterpene, sphaerodactylomelol (1), induced inhibition of cell proliferation (IC50 280 μM) and cytotoxicity (IC50 720 μM) on HepG-2 cells and showed antimicrobial activity against S. aureus (IC50 96.3 μM).
- The potential of cholinesterases as tools for biomonitoring studies with sharks: Biochemical characterization in brain and muscle tissues of Prionace glaucaPublication . Alves, Luís M.; Lemos, Marco F.L.; Correia, João P. S.; Costa, Nuno A.R. da; Novais, Sara C.Cholinesterases (ChE) are a family of enzymes that play an essential role in neuronal and motor functions. Because of the susceptibility of these enzymes to anticholinergic agents and to other contaminants, their activity is frequently used as biomarker in pollution monitoring studies. The three known types of ChE in fish are acetilcholinesterase (AChE), butyrylcholinesterase (BChE) and propionylcholinesterase (PChE). The presence of these enzymes in each tissue differs between species, and thus their usage as biomarkers requires previous enzyme characterization. Sharks, mostly acting as apex predators, help maintain the balance of fish populations performing a key role in the ecosystem. Blue sharks (Prionace glauca) are one of the most abundant and heavily fished sharks in the world, thus being good candidate organisms for ecotoxicology and biomonitoring studies. The present study aimed to characterize the ChE present in the brain and muscle of the blue shark using different substrates and selective inhibitors, and to assess the in vitro sensitivity of these sharks' ChE to chlorpyrifos-oxon, a metabolite of a commonly used organophosphorous pesticide, recognized as amodel anticholinesterase contaminant. The results suggest that the brain of P. glauca seems to contain atypical ChEs, displayingmixed properties of AChE and BChE, and that the muscle tissue seems to contain mainly AChE. In vitro exposures to chloropyrifosoxon inhibited blue shark's ChE in both tissues, the brain being the most sensitive tissue and therefore the most suitable for detection of exposure to low concentrations of anticholinergic compounds in the environment. This study indicates that ChE activity in blue sharks has the potential to be used as a sensitive and reliable biomarker in marine biomonitoring programs.
- Sea cucumber Holothuria forskali, a new resource for aquaculture? Reproductive biology and nutraceutical approachPublication . Santos, Rita; Dias, Simaura; Pinteus, Susete; Silva, Joana; Alves, Celso; Tecelão, Carla; Pedrosa, Rui; Pombo, AnaSea cucumbers are highly marketable as a food product due to their nutritional value. Also, it has been suggested that sea cucumbers possess a wide range of bioactive compounds that can be used in the pharmaceutical industry. In this study, the reproductive biology of Holothuria forskali was performed by evaluating the gonadosomatic index (GI) and histological analyses of the gonadal tubules. The biotechnological potential was assessed through the evaluation of the antioxidant, antimicrobial and antitumor potential. Finally, the fatty acid profile was also evaluated. These three subjects were chosen to increase the interest and to focus the economic potential of this species rearing, predicting that it can be sold in Europe or export to Asia to be used for human consumption or for the pharmaceutical industry. The GI and the histological analysis of the gonadal tubules revealed that the range from February to March corresponds to the peak of gonads maturation. Furthermore, the methanolic fraction revealed the highest antimicrobial potential against Candida albicans with an IC50 of 233.2 mg mL -1. Also, this fraction presented the highest cytotoxic and anti-proliferative activities through the method for measuring cell proliferation method in both cell lines, with an IC50 of 238.2 and 396.0 mg mL -1 for MCF-7 cells respectively and 260.3 and 218.7 mg mL -1 for HepG-2 cells respectively. Regarding the fatty acid profile, the total fat content was 4.83% and the highest values were obtained for palmitic acid (9.96%), stearic acid (11.23%), eicosapentaenoic acid (10.49%) and arachidonic acid (20.36%).
- Is integrated multitrophic aquaculture the solution to the sectors’ major challenges? – a reviewPublication . Almeida, Luana; Sousa, Nádia; Lopes, Sofia; Lemos, MarcoThe growing demand for fish products and the dwindling productivity of marine fish stocks due to the overexploitation of fisheries place the aquaculture industry as a key contributor to the global fish supply. The intensive development of aquaculture has raised a range of environmental concerns such as effluent discharge, excessive use of resources and dependence on commercial feed. In this context, the development of sustainable aquaculture systems is becoming the cornerstone for long-term aquaculture expansion, and to achieve environmental sustainability. Integrated multitrophic aquaculture (IMTA) is regarded as a suitable approach to limit aquaculture nutrients and organic matter outputs through biomitigation. The cocultured species are used as biofilters, and each level has its own independent commercial value, providing both economic and environmental sustainabil ity. Here, environmental issues of aquaculture and the current status of IMTA are reviewed and its future prospects discussed. Also, the opportunities to expand this systems’ complexity with increased added-value and trophic levels are introduced.