Browsing by Issue Date, starting with "2024-08-26"
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- Multi-marker DNA metabarcoding for precise species identification in ichthyoplankton samplesPublication . Ferreira, André O.; Barroso, Cristina; Mouteira Azevedo, Olga; Duarte, Sofia; Egas, Conceição; Fontes, João T.; Ré, Pedro; Santos, A. Miguel P.; Costa, Filipe O.Ichthyoplankton monitoring is crucial for stock assessments, offering insights into spawning grounds, stock size, seasons, recruitment, and changes in regional ichthyofauna. This study evaluates the efficiency of multi-marker DNA metabarcoding using mitochondrial cytochrome c oxidase subunit I (COI), 12S rRNA and 16S rRNA gene markers, in comparison to morphology-based methods for fish species identification in ichthyoplankton samples. Two transects with four coastal distance categories were sampled along the southern coast of Portugal, being each sample divided for molecular and morphological analyses. A total of 76 fish species were identified by both approaches, with DNA metabarcoding overperforming morphology-75 versus 11 species-level identifications. Linking species-level DNA identifications with higher taxonomic morphological identifications resolved several uncertainties associated with traditional methods. Multi-marker DNA metabarcoding improved fish species detection by 20-36% compared to using a single marker/amplicon, and identified 38 species in common, reinforcing the validity of our results. PERMANOVA analysis revealed significant differences in species communities based on the primer set employed, transect location, and distance from the coast. Our findings underscore the potential of DNA metabarcoding to assess ichthyoplankton diversity and suggest that its integration into routine surveys could enhance the accuracy and comprehensiveness of fish stock assessments.
- Geographic information system in the optimization of tourist routes in the city of Faro (Algarve, Portugal)Publication . Granja Martins, Fernando Miguel; Maria Neto Paixão Vazquez Fernandez Martins, HelenaThis work aims to map the optimal routes based on time and distance, via e-scooters and walking, to visit 54 historical heritage sites in Faro. Implementing these routes promotes environmental sustainability by reducing CO2 emissions and encouraging healthier, greener tourism. The route optimization was conducted in ArcGIS, utilizing the Network Analyst extension and vector data obtained from OpenStreetMap. The results showed that there are routes that can be completed in one or more days, depending on visitors' availability, physical capacity, or their chosen method of transportation. The optimal route to visit the 54 historical heritage sites forms a closed circuit spanning 17.35 km. If visits are split into two routes, one covering 31 monuments in the old city and the other 24 monuments in the exterior area of the urban center, the optimal closed-circuit routes measure 6.16 km and 11.31 km, respectively. This study is expected to enhance tourism promoted by the Faro municipality and make it more environmentally friendly.
- Excitation–contraction coupling reflects the metabolic profile of mantle muscle in young cuttlefishPublication . Callaghan, Neal I.; Ducros, Loïck; Bennett, J. Craig; Capaz, Juan Carlos; Andrade, José Pedro Andrade; Sykes, António; Driedzic, William R.; Lamarre, Simon G.; MacCormack, Tyson J.The mantle muscle of common cuttlefish, Sepia officinalis, is responsible both for high-magnitude and rapid movements for locomotion, as well as sustained ventilation, which require specific metabolic, electrophysiological, and structural organization. Young cuttlefish have a highly oxidative phenotype and a rapid growth rate. Here, we show high rates of oxygen consumption and protein synthesis in juveniles, and these rates decay exponentially over the first few weeks of growth. This is associated with considerable citrate synthase activity (relative to larger cuttlefish) but a lack of glucose metabolism based on zero uptake of glucose by isolated muscle sheets and minimal activity of hexokinase (similar to larger animals). In contrast to glucose metabolism in the heart, glucose metabolism in these muscle sheets was not stimulated by extracellular taurine. Previous research revealed an unusual ion channel complement in mantle myocytes, the most notable feature of which is the lack of a Na+ current during depolarization. Because this adaptation is not consistent across the coleoid clade, we investigated excitation-contraction coupling. Here, mantle energetics and contractility, including the individual components of the total Ca2+ flux driving contraction, were studied. Results indicate that the majority of Ca2+ current underlying contractile stress development capacity in cuttlefish juveniles is not mediated by dihydropyridine-sensitive L-type channels, in contrast to their adult counterparts, and the sarcoplasmic reticulum contributes little to routine contractility. We had previously noted an influence of physiological levels of taurine in limiting cardiac contractility but found no analogous sensitivity in mantle muscle. Finally, transmission electron microscopy of subcellular architecture revealed the presence of sarcoplasmic tubular aggregates, suggesting that oxidative inhibition of sarcoplasmic reticulum function limits its role in this life stage.