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Browsing CCMAR by Field of Science and Technology (FOS) "Engenharia e Tecnologia::Outras Engenharias e Tecnologias"
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- By-catch species susceptibilities and potential for survival in Algarve (South Portugal) deep-water crustacean trawl fisheryPublication . Adão, Ana Catarina Vasconcelos; Borges, Teresa C.; Breen, MikeBottom trawling for crustaceans in Portuguese coastal waters constitutes a rather important fishery in revenue terms, despite its clear negative impacts on deep-sea communities and marine ecosystems. This poorly selective harvest strategy catches large amounts of unwanted species that are thrown overboard for various reasons. However, survival of discards is not yet properly assessed and constitutes an essential parameter for the upcoming landing obligation, with an exemption for species with “high survival”. In this work, time-to-mortality and a vitality assessment were used to estimate immediate mortality and identify important biological characteristics on the susceptibility of a group of 14 by-catch species, most with commercial interest (Conger conger, Galeus melastomus, Helicolenus dactylopterus, Lepidorhombus boscii, Lophius budegassa, Lophius piscatorius, Merluccius merluccius, Micromesistius poutassou, Mullus surmuletus, Phycis blennoides, Scyliorhinus canicula, Trigla lyra, Trachurus trachurus and Trachurus picturatus). Only S. canicula and C. conger were identified as species with potential to survive after the discarding process. Present results on time-to-mortality show significant differences when comparing individual sizes for some species, with smaller individuals dying faster than larger ones. Furthermore, species with scales, gas bladder and high metabolic rates are more vulnerable to die after being discarded. A short captive observation experiment with C. conger was conducted, with 84% survival after 65 hours of monitoring. However, this survival rate is likely to be overestimated due to two facts: 1) the mortality rate did not stabilize at the end of the experiment; and 2) the majority of individuals showed severe injuries (scratches, bruises and deep wounds). These outcomes can help to identify species that will likely survive the discarding process, factors influencing its survival and provide reliable estimates of unaccounted fishing mortality, essential for stock management and conservation.
- Searching for biocompounds in algae and seagrasses with potential use in thetreatment of Alzheimer’s diseasePublication . Silvestre, Águeda Laura dos Santos; Varela, J.; Custódio, Luísa Margarida BatistaThe number of older people at risk of developing dementia is growing rapidly worldwide, and Alzheimer’s disease (AD) represents the most common cause of dementia in the elderly. The principal characteristics of AD include the presence of amyloid plaques, neurofibrillary tangles, brain atrophy in specific brain areas and loss of the neurotransmitter acetylcholine (ACh), which is hydrolysed by the cholinesterases (ChE) acetylcholinesterase (AChE) and secondly by butyrilcholinesterase (BChE). Pharmacological treatments currently used to alleviate AD symptoms include ChE inhibitors, but they exhibit bioavailability problems and side effects like hepatotoxicity and gastrointestinal disorders. Thus, there is a high interest in finding better ChE inhibitors from natural sources. Due to the high oxygen consumption and lipid content, the central nervous system (CNS) is more sensitive to oxidative stress compared to other parts of our body. Thus, special interest has been assigned in nutritional antioxidants and metal chelation therapy as viable neuroprotective approaches for neurodegenerative disorders. Marine organisms are recognized as rich sources of novel biologically active compounds. However, its application in the treatment of neurological disorders is still scarcely explored. In this context, the main goal of this study was to evaluate the AChE and BChE inhibitory activity of methanol extracts made from different species of macro- and microalgae, seagrasses and halophytes, as well as evaluate their chelating activity on iron (Fe2+) and copper (Cu2+) ions. The most active species against both enzymes were the brown macroalgae Cystoseira compressa, C. nodicaulis and C. tamariscifolia and the halophytes Carpobrotus edulis and Frankenia laevis. The chelating activity was higher for Cu2+ than for Fe2+ in the majority of the species tested, being the most active the red macroalgae Plocamium cartilageneum. These species are thus promising candidates for more detailed in vitro and in vivo studies aiming their use as sources of innovative products with neuroprotective aplications.