9 documents found, page 1 of 1
Ecophysiological effects of mercury bioaccumulation and biochemical stress in t...
Rodrigues, Andreia C. M.; Gravato, Carlos; Galvão, Daniela; Silva, Virgília S.; Soares, Amadeu M. V. M.; Gonçalves, Jorge M. S.; Ellis, Jim R.Mercury (Hg) is a non-essential metal that can have toxic effects on the fitness of organisms and tends to bioaccumulate with age and to biomagnify in higher trophic levels. Few studies have assessed oxidative stress and neurotoxicity in deep-water sharks. This study evaluated early ontogenetic changes and physiological effects (antioxidant defences, oxidative damage, aerobic metabolism and neurotransmission fu...
Ecophysiological effects of mercury bioaccumulation and biochemical stress in t...
Rodrigues, Andreia C.M.; Gravato, Carlos; Galvão, Daniela; Silva, Virgília S.; Soares, Amadeu M.V.M.; Gonçalves, Jorge Manuel Santos; Ellis, Jim R.Mercury (Hg) is a non-essential metal that can have toxic effects on the fitness of organisms and tends to bioaccumulate with age and to biomagnify in higher trophic levels. Few studies have assessed oxidative stress and neurotoxicity in deep-water sharks. This study evaluated early ontogenetic changes and physiological effects (antioxidant defences, oxidative damage, aerobic metabolism and neurotransmission fu...
Biocompatible hybrids based on nanographene oxide covalently linked to glycolpo...
Santos, Carla I.M.; Gonçalves, Gil; Cicuéndez, Monica; Mariz, Inês; Silva, Virgília S.; Oliveira, Helena; Campos, Fábio; Vieira, Sandra I.The major limitation in the development of hybrids based on graphene oxide (GO) and porphyrins is their dispersibility and stability in aqueous systems due to the hydrophobic character induced by porphyrins. Most of the previous approaches reported the direct functionalization of GO with polyethylene glycol (PEG) chains followed by the self-assembly of porphyrins by π-π interactions. Here, new hybrids were prep...
Differences in the expression pattern of HCN isoforms among mammalian tissues: ...
Calejo, Ana I.; Reverendo, Marisa; Silva, Virgília S.; Pereira, Patrícia M.; Santos, Manuel A. S.; Zorec, Robert; Gonçalves, Paula P.Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels play a critical role in a broad range of cell types, but the expression of the various HCN isoforms is still poorly understood. In the present study we have compared the expression of HCN isoforms in rat excitable and non-excitable tissues at both the mRNA and protein levels. Real-time PCR and Western blot analysis revealed distinct expression p...
Automated high-throughput screening of carbon nanotube-based bio-nanocomposites...
Gonçalves, Paula P.; Singh, Manoj K.; Silva, Virgília S.; Marques, Filipa; Marques, Ana; LeDuc, Philip R.; Grácio, José; Marques, Paula A. A. P.In this work we demonstrate the potential of using an automated cell viability analyzer for developing high-throughput screening of orthopedic bioactive materials. We used a biomaterial of carbon nanotubes (CNTs)-based composite integrated with hydroxyapatite/ polymethyl methacrylate (HA/PMMA) with controlled physical and chemical properties to evaluate the usefulness of morphometric analysis in conjunction wit...
Acetylcholine release and choline uptake by cuttlefish (Sepia officinalis) opti...
Nunes, M. Alexandra; Santos, Sofia; Cordeiro, J. Miguel; Neves, Paulo; Silva, Virgília S.; Sykes, António V.; Morgado, Fernando; Dunant, YvesAcetylcholine (ACh), which is synthesized from choline (Ch), is believed to hold a central place in signaling mechanisms within the central nervous system (CNS) of cuttlefish (Sepia officinalis) and other coleoid cephalopods. Although the main elements required for cholinergic function have been identified in cephalopods, the transmembrane translocation events promoting the release of ACh and the uptake of Ch r...
Comparative effects of aluminum and ouabain on synaptosomal choline uptake, ace...
Silva, Virgília S.; Nunes, M. Alexandra; Cordeiro, J. Miguel; Calejo, Ana I.; Santos, Sofia; Neves, Paulo; Sykes, António V.; Morgado, FernandoClosing the gap between adverse health effects of aluminum and its mechanisms of action still represents a huge challenge. Cholinergic dysfunction has been implicated in neuronal injury induced by aluminum. Previously reported data also indicate that in vivo and in vitro exposure to aluminum inhibits the mammalian (Na(+)/K(+))ATPase, an ubiquitous plasma membrane pump. This study was undertaken with the specifi...
The inhibitory effect of aluminium on the (Na+/K+)ATPase activity of rat brain ...
Silva, Virgília S.; Gonçalves, Paula P.The effect of AlCl3 on the (Na+ /K+)ATPase activity of freeze-thawed synaptosomes, isolated from rat brain cortex, has been studied. The AlCl3 action on the enzyme hydrolytic activity was examined using in vitro and in vivo approaches. Following exposure to AlCl3 using both in vitro (synaptosomes incubated in the presence of AlCl3 for 5 min) and in vivo (synaptosomes isolated from rats that received 0.03 g AlCl...
Aluminum accumulation and membrane fluidity alteration in synaptosomes isolated...
Silva, Virgília S.; Cordeiro, J. Miguel; Matos, Manuel J.; Oliveira, Catarina R.; Gonçalves, Paula P.In the present work, we studied the effect of cholesterol/phospholipid (CH/PL) molar ratio on aluminum accumulation and aluminum-induced alteration of membrane fluidity in rat brain cortex synaptosomes. We observed that sub-acute (daily supply of 1.00 g of AlCl3 during 10 days) and chronic (daily supply of 0.03 g of AlCl3 during 4 months) exposure to dietary aluminum leads to a synaptosomal aluminum enrichment ...