Mostrando recursos 1 - 20 de 1.086

  1. New endoperoxides highly active in vivo and in vitro against artemisinin-resistant Plasmodium falciparum

    Lobo, Lis; Cabral, Lília I. L.; Sena, Maria I.; Guerreiro, Bruno; Rodrigues, António S.; de Andrade-Neto, Valter F.; Cristiano, Maria Lurdes Santos; Nogueira, Fatima
    Background: The emergence and spread of Plasmodium falciparum resistance to artemisinin-based combination therapy in Southeast Asia prompted the need to develop new endoperoxide-type drugs. Methods: A chemically diverse library of endoperoxides was designed and synthesized. The compounds were screened for in vitro and in vivo anti-malarial activity using, respectively, the SYBR Green I assay and a mouse model. Ring survival and mature stage survival assays were performed against artemisinin-resistant and artemisinin-sensitive P. falciparum strains. Cytotoxicity was evaluated against mammalian cell lines V79 and HepG2, using the MTT assay. Results: The synthesis and anti-malarial...

  2. The Influence of environmental factors and fishing pressure on catch rates of diplodus vulgaris

    Baptista, Vania; Campos, Carlos J. A.; Leitão, Francisco
    The variability of coastal marine resources has been linked to environmental variability but the impacts of artisanal nearshore fishing activity and environmental factors interact in different ways. Time series, Min/Max Autocorrelation Factor, Generalised Least Squares and Dynamic Factor Analyses models were applied to examine the role of environmental factors (SST, NAO Index, Upwelling Index, Wind Magnitude, Easterly Wind Component, Northerly Wind Component, Coastal River Discharges) and fisheries effort on commercial catch rates of Diplodus vulgaris in the Northwest, Southwest and South Portuguese coast. Environmental factors were found to affect short-term variations of catch rates with a time lag of 2...

  3. Recovery of gold(0) nanoparticles from aqueous solutions using effluents from a bioremediation process

    Assunção, Ana; Vieira, Bernardete; Lourenço, J. P.; Costa, Maria Clara
    The use of biological processes with the aim of the recovery of gold from low-concentration solutions derived from leaching of secondary sources is gaining increasing importance owing to the scarcity of the primary resources and the economic and environmental advantages usually presented by these methods. Thus, the addition in batch and continuous processes of different solutions containing biogenic sulphide, which was generated by the activity of sulphate-reducing bacteria (SRB), to gold(III) solutions was investigated for that purpose. In the batch experiments, AuS nanoparticles with sizes of between 6 and 14 nm were obtained (corresponding to 100% removal of Au(III) from...

  4. Application of urea-agarose gel electrophoresis to select non-redundant 16S rRNAs for taxonomic studies: palladium(II) removal bacteria

    Assunção, Ana; Costa, Maria Clara; Carlier, Jorge Dias
    The 16S ribosomal RNA (rRNA) gene has been the most commonly used sequence to characterize bacterial communities. The classical approach to obtain gene sequences to study bacterial diversity implies cloning amplicons, selecting clones, and Sanger sequencing cloned fragments. A more recent approach is direct sequencing of millions of genes using massive parallel technologies, allowing a large-scale biodiversity analysis of many samples simultaneously. However, currently, this technique is still expensive when applied to few samples; therefore, the classical approach is still used. Recently, we found a community able to remove 50 mg/L Pd(II). In this work, aiming to identify the bacteria...

  5. A bridge between liquid-liquid extraction and the use of bacterial communities for palladium and platinum recovery as nanosized metal sulphides

    Assunção, Ana; Matos, Ana; Costa, Ana M. Rosa da; Candeias, Antonio; Costa, Maria Clara
    The Platinum Group Metals (PGM) are rare in the Earth's crust and in the past years their use had a considerable expansion limiting their availability, which justifies PGM's high commercial value and demand. Therefore, PGM recovery from secondary sources is very important from both economic and environmental points of view. In recent years, several methods for PGM removal have been investigated. Our research group has been studying the removal/recovery of PGM using both chemical (liquid liquid extraction) and biological methods (using anaerobic bacterial communities).The aim of this study was to combine these two chemical and biological approach technologies, for PGM...

  6. Technical note: Algal Pigment Index 2 in the Atlantic off the southwest Iberian Peninsula: standard and regional algorithms

    Goela, Priscila; Cristina, Sonia; Kajiyama, Tamito; Icely, John; Moore, Gerald; Fragoso, Bruno; Newton, Alice
    In this study, Algal Pigment Index 2 (API2) is investigated in Sagres, an area located in the Atlantic off the southwestern Iberian Peninsula. Standard results provided by the MEdium Resolution Image Spectrometer (MERIS) ocean colour sensor were compared with alternative data products, determined through a regional inversion scheme, using both MERIS and in situ remote sensing reflectances (R-rs) as input data. The reference quantity for performance assessment is in situ total chlorophyll a (TChl a) concentration estimated through a phytoplankton absorption coefficient (i.e. equivalent to API2). Additional comparison of data products has also been addressed for TChl a concentration determined...

  7. Response of seagrass indicators to shifts in environmental stressors: A global review and management synthesis

    Roca, G.; Alcoverro, T.; Krause-Jensen, D.; Balsby, T. J. S.; van Katwijk, M. M.; Marba, N.; Santos, Rui; Arthur, R.; Mascaro, O.; Fernandez-Torquemada, Y.; Perez, M.; Duarte, C. M.; Romero, J.
    Although seagrass-based indicators are widely used to assess coastal ecosystem status, there is little universality in their application. Matching the plethora of available indicators to specific management objectives requires a detailed knowledge of their species-specific sensitivities and their response time to environmental stressors. We conducted an extensive survey of experimental studies to determine the sensitivity and response time of seagrass indicators to ecosystem degradation and recovery. We identified seagrass size and indicator type (i.e. level of biological organization of the measure) as the main factors affecting indicator sensitivity and response time to degradation and recovery. While structural and demographic parameters...

  8. Linderiella baetica Alonso & Garcia-de-Lomas 2009 (Crustacea, Branchiopoda, Anostraca): On the verge of extinction?

    Garcia de Lomas, Juan; Garcia, Carlos M.; Hortas, Francisco; Prunier, Florent; Boix, Dani; Sala, Jordi; Leon, David; Serrano, Laura; Prenda, José; Diego Gilbert, Juan; Guerrero, Francisco J.; Marrone, Federico; Sahuquillo, Maria; Camacho, Antonio; Olmo, Carla; Rosa Miracle, Maria; Zamora-Munoz, Carmen; Mura, Graziella; Machado, Margarida; Sanchez, Inigo; Angel Galvez, José; Florencio, Margarita; Luis Perez-Bote, José; Alonso, Miguel
    The province of Cadiz (South of Spain) hosts the only known locality in the world of Linderiella baetica Alonso & Garcia-de-Lomas 2009 (Anostraca). In this paper, the geographical distribution of the species based on published sampling data focused on large branchiopods and temporary pools in Andalusia and the entire Iberian Peninsula is assessed. The current situation is summarized based on the threats to their survival, which are mainly related to habitat alteration. In the Iberian Peninsula, at least 1,648 bodies of water (about 720 in Andalusia) have been explored. Prevalence data suggest that L. baetica is a rare species (localities...

  9. New insights about the introduction of the Portuguese oyster, Crassostrea angulata, into the North East Atlantic from Asia based on a highly polymorphic mitochondrial region

    Lallias, Delphine; Power, Deborah; Ruano, Francisco; Leitão, Alexandra; Drago, Teresa; King, Jonathan W.; Boudry, Pierre; Batista, Frederico M.
    It is commonly presumed that the Portuguese oyster Crassostrea angulata was introduced into the North East (NE) Atlantic from Asia. The analysis of the nucleotide sequence of a highly polymorphic non-coding mitochondrial region (major noncoding region - MNR) of C. angulata samples collected in Europe (Portugal), Africa (Morocco) and Asia (Shantou and Taiwan) provided new insight into the introduction of this species into the NE Atlantic. Sixty haplotypes and a nucleotide diversity of 0.0077 were observed in 130 analyzed sequences. Higher nucleotide diversity levels were observed in NE Atlantic sites than in Asian sites and significant genetic differentiation was found...

  10. Dietary butyrate helps to restore the Intestinal status of a marine teleost (Sparus aurata) fed extreme diets low in fish meal and fish oil

    Estensoro, Itziar; Ballester-Lozano, Gabriel; Benedito-Palos, Laura; Grammes, Fabian; Martos-Sitcha, Juan Antonio; Mydland, Liv-Torunn; Calduch-Giner, Josep Alvar; Fuentes, Juan; Karalazos, Vasileios; Ortiz, Alvaro; Overland, Margareth; Sitja-Bobadilla, Ariadna; Perez-Sanchez, Jaume
    There is a constant need to find feed additives that improve health and nutrition of farmed fish and lessen the intestinal inflammation induced by plant-based ingredients. The objective of this study was to evaluate the effects of adding an organic acid salt to alleviate some of the detrimental effects of extreme plant-ingredient substitution of fish meal (FM) and fish oil (FO) in gilthead sea bream diet. Three experiments were conducted. In a first trial (T1), the best dose (0.4%) of sodium butyrate (BP-70 (R) NOREL) was chosen after a short (9 weeks) feeding period. In a second longer trial (T2)...

  11. Ear wound regeneration in the African spiny mouse Acomys cahirinus

    Santos, Dino Matias; Rita, Ana Martins; Casanellas, Ignasi; Ova, Adelia Brito; Araújo, Inês; Power, Deborah; Tiscornia, Gustavo
    While regeneration occurs in a number of taxonomic groups across the Metazoa, there are very few reports of regeneration in mammals, which generally respond to wounding with fibrotic scarring rather than regeneration. A recent report described skin shedding, skin regeneration and extensive ear punch closure in two rodent species, Acomys kempi and Acomys percivali. We examined these striking results by testing the capacity for regeneration of a third species, Acomys cahirinus, and found a remarkable capacity to repair full thickness circular punches in the ear pinna. Four-millimeter-diameter wounds closed completely in 2 months in 100% of ear punches tested. Histology...

  12. Isolation Driven Divergence in Osmoregulation in Galaxias maculatus (Jenyns, 1848) (Actinopterygii: Osmeriformes)

    Ruiz-Jarabo, Ignacio; Gonzalez-Wevar, Claudio A.; Oyarzun, Ricardo; Fuentes, Juan; Poulin, Elie; Bertran, Carlos; Vargas-Chacoff, Luis
    BackgroundMarine species have colonized extreme environments during evolution such as freshwater habitats. The amphidromous teleost fish, Galaxias maculatus is found mainly migrating between estuaries and rivers, but some landlocked populations have been described in lakes formed during the last deglaciation process in the Andes. In the present study we use mtDNA sequences to reconstruct the historical scenario of colonization of such a lake and evaluated the osmoregulatory shift associated to changes in habitat and life cycle between amphidromous and landlocked populations.ResultsStandard diversity indices including the average number of nucleotide differences (Pi) and the haplotype diversity index (H) indicated that both...

  13. By-catch species susceptibilities and potential for survival in Algarve (South Portugal) deep-water crustacean trawl fishery

    Adão, Ana Catarina Vasconcelos
    Dissertação de mestrado, Aquacultura e Pescas, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2017

  14. Assessing the effects of Tidal Energy Converter array size on hydrodynamics of Ria Formosa (Portugal)

    González-Gorbeña, Eduardo; Pacheco, André; Plomaritis, Theocharis A.; Sequeira, Cláudia
    This paper investigates the effects of Tidal Energy Converter (TEC) array size at a tidal channel on flood/ebb discharges at multi-inlet coastal lagoon by applying numerical modelling. The paper presents a case study for the Faro-Olhão inlet in the Ria Formosa (Portugal), a potential site for tidal in-stream energy extraction. Arrays of up to 11 rows with 5 TECs each were studied to assess impacts on inlets discharges changes. For the particular cases assessed the results show that tidal energy extraction will have a greater impact on Ancão and Armona inlets discharges together with the Faro-Olhão inlet. Future work is...

  15. Assessing the effects of Tidal Energy Converter array size on hydrodynamics of Ria Formosa (Portugal)

    González-Gorbeña, Eduardo; Pacheco, André; Plomaritis, Theocharis A.; Sequeira, Cláudia

  16. Synthesis and characterization of Locust Bean Gum derivatives and their application in the production of nanoparticles

    Braz, L.; Grenha, Ana; Corvo, Marta C.; Lourenço, J. P.; Ferreira, Domingos; Sarmento, Bruno; Costa, Ana M. Rosa da
    The development of LBG-based nanoparticles intending an application in oral immunization is presented. Nanoparticle production occurred by mild polyelectrolyte complexation, requiring the chemical modification of LBG. Three LBG derivatives were synthesized, namely a positively charged ammonium derivative (LBGA) and negatively charged sulfate (LBGS) and carboxylate (LBGC) derivatives. These were characterized by Fourier-transform infrared spectroscopy, elemental analysis, nuclear magnetic resonance spectroscopy, gel permeation chromatography, and x-ray diffraction. As a pharmaceutical application was aimed, a toxicological analysis of the derivatives was performed by both MTT test and LDH release assay. Several nanoparticle formulations were produced using LBGA or chitosan (CS) as positively...

  17. Foraging niche segregation between juvenile and adult hawksbill turtles (Eretmochelys imbricata) at Príncipe island, West Africa

    Ferreira, Rogério L.; Ceia, Filipe R.; Borges, Teresa C.; Ramos, Jaime A.; Bolten, Alan B.
    Hawksbill sea turtles are the most tropical sea turtle species with one of the last remaining aggregations in West Africa found on Príncipe Island (1° 37′ N; 7° 23′ E). Here we present for the first time, data on the trophic and foraging ecology of both juvenile and adult hawksbill turtles found in the shallow waters of Príncipe, using stable isotope analyses of carbon (δ13C) and nitrogen (δ15N), and assess any isotopic niche segregation between these two life-stages. Hawksbill turtles were sampled from December 2012 to June 2014, complementary to a snorkeling survey conducted around the entire coastline (ca. 100...

  18. In vitro and in silico approaches to appraise Polygonum maritimum L. as a source of innovative products with anti-ageing potential

    Rodrigues, Maria João; Slusarczyk, Sylwester; Pecio, Łukasz; Matkowski, Adam; Salmas, Ramin Ekhteiari; Durdagi, Serdar; Pereira, Catarina; Varela, J.; Barreira, Luísa; Custódio, Luísa
    Different Polygonum species have in vitro neuroprotective properties and are traditionally used for their anti-ageing benefits. In this context this work explored for the first time P. maritimum (sea knotgrass) as a potential source of natural products with industrial application as cognitive enhancers with anti-ageing potential. For that purpose methanol and dichloromethane extracts were prepared from leaves and roots of that species and evaluated for in vitro neuroprotective effects through the inhibition on acetyl- (AChE) and butyrylcholinesterase (BuChE), protection against hydrogen peroxide (H2O2)-induced cytoxicity on neuroblastoma cells and lipopolysaccharide (LPS)-induced neuroinflammation on microglia cells. The extracts were chemically characterized by...

  19. The P-type ATPase inhibiting potential of polyoxotungstates.

    Gumerova, Nadiia; Krivosudský, Lukáš; Fraqueza, Gil; Breibeck, Joscha; Al-Sayed, Emir; Tanuhadi, Elias; Bijelic, Aleksandar; Fuentes, Juan; Aureliano, M.; Rompel, Annette
    Polyoxometalates (POMs) are transition metal complexes that exhibit a broad diversity of structures and properties rendering them promising for biological purposes. POMs are able to inhibit a series of biologically important enzymes, including phosphatases, and thus are able to affect many biochemical processes. In the present study, we analyzed and compared the inhibitory effects of nine different polyoxotungstates (POTs) on two P-type ATPases, Ca2+-ATPase from skeletal muscle and Na+/K+-ATPase from basal membrane of skin epithelia. For Ca2+-ATPase inhibition, an in vitro study was performed and the strongest inhibitors were determined to be the large heteropolytungstate K9(C2H8N)5[H10Se2W29O103] (Se2W29) and the Dawson-type...

  20. Membrane-enriched proteome changes and prion protein expression during neural differentiation and in neuroblastoma cells

    Macedo, J. A.; Schrama, D.; Duarte, I.; Tavares, E.; Renaut, J.; Futschik, M. E.; Rodrigues, P. M.; Melo, E. P.
    Background The function of the prion protein, involved in the so-called prion diseases, remains a subject of intense debate and the possibility that it works as a pleiotropic protein through the interaction with multiple membrane proteins is somehow supported by recent reports. Therefore, the use of proteomic and bioinformatics combined to uncover cellular processes occurring together with changes in the expression of the prion protein may provide further insight into the putative pleiotropic role of the prion protein. Results This study assessed the membrane-enriched proteome changes accompanying alterations in the expression of the prion protein. A 2D-DIGE approach...

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