249 research outputs found

    A Ni hyperaccumulator and a congeneric non-accumulator reveal equally effective defenses against herbivory

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    The defense hypothesis is commonly used to explain the adaptive role ofmetal hyperaccumulation. We tested this hypothesis using two Brassicaceae congeneric species: Alyssum pintodasilvae, a Ni hyperaccumulator, and the non-accumulator Alyssum simplex both growing on serpentine soils in Portugal. Artificial diet disks amended with powdered leaves from each plant species were used to compare the performance (mortality, biomass change) and feeding behavior of Tribolium castaneum in no-choice and choice tests. The performance of T. castaneum was not affected at several concentrations of A. pintodasilvae or A. simplex in no-choice tests. However, the consumption of plant-amended disks was significantly lower than that of control disks, irrespectively of the species fed. Accordingly, when insects were given an alternative food choice, disks of both plant species were significantly less consumed than control disks. Moreover, insects did not discriminate between disks in the combination “A. pintodasilvae + A. simplex”. Contrary to our expectations, these results suggest that both plant species have equally effective defenses against herbivory. While Ni is believed to be part of the deterrence mechanism in the hyperaccumulator A. pintodasilvae, it seems likely that organic compounds, possibly glucosinolates, play an important role in the defense of A. simplex or in both species.This study was fully supported by the Centre for Functional Ecology, University of Coimbra

    Photolytic release at different wavelengths of tetrapeptide AAPV from a pyrenylmethyl conjugate

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    Comunicação em painel no 2nd Symposium on Medicinal Chemistry, Braga, Portugal, 8 Maio 2015The present work describes the photolysis of ester conjugate NH2-Ala-Ala-Pro-Val-Pym, with Pym being the pyrenylmethylene group, at different wavelengths of irradiation in different solvents and simulated physiological environment. The photolysis of the ester conjugate and the release of the free tetrapeptide was monitored by HPLC with UV detection, with collection of kinetic data.Fundação para a Ciência e Tecnologia(FCT, Portugal) for financial support to the NMR portuguese network (PTNMR, Bruker Avance III 400-Univ. Minho), FCT and FEDER (European Fund for Regional Development)-COMPETE -QREN-EU for financial support to Research Centre of Chemistry, CQ/UM [PEst -C/QUI/UI0686/2013 (FCOMP-01-0124-FEDER-037302)]info:eu-repo/semantics/publishedVersio

    A photolabile prodrug of tetrapeptide AAPV bearing 7-methoxycoumarin at the C-terminal

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    Comunicação em painel QS30 no livro de resumos do XX Encontro Luso-Galego de Químicathe present work describes the evaluation as a photolabile prodrug of a fluorescent conjugate of the tetrapeptide AAPV labeled at the C-terminus with 7-methoxycoumarin. This conjugate was submitted to photocleavage studies at different wavelengths of irradiation in different solvents and simulated physiological environment in order to study the release of the peptide. The photolysis process was monitored by HPLC with UV detection and 1H NMR, with collection of kinetic data.Fundação para a Ciência e a Tecnologia (FCT

    Assessment of physical vulnerability of buildings and analysis of landslide risk at the municipal scale: application to the Loures municipality, Portugal

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    This study offers a semi-quantitative assessment of the physical vulnerability of buildings to landslides in a Portuguese municipality (Loures), as well as the quantitative landslide risk analysis computed as the product of the landslide hazard by the vulnerability and the economic value of the buildings. The hazard was assessed by combining the spatiotemporal probability and the frequency–magnitude relationship of the landslides. The physical vulnerability assessment was based on an inquiry of a pool of European landslide experts and a sub-pool of landslide experts who know the study area, and the answers’ variability was assessed with standard deviation. The average vulnerability of the basic geographic entities was compared by changing the map unit and applying the vulnerability to all the buildings of a test site, the inventory of which was listed on the field. The economic value was calculated using an adaptation of the Portuguese Tax Services approach, and the risk was computed for different landslide magnitudes and different spatiotemporal probabilities. As a rule, the vulnerability values given by the sub-pool of experts who know the study area are higher than those given by the European experts, namely for the high-magnitude landslides. The obtained vulnerabilities vary from 0.2 to 1 as a function of the structural building types and the landslide magnitude, and are maximal for 10 and 20m landslide depths. However, the highest risk was found for the landslides that are 3m deep, because these landslides combine a relatively high frequency in the Loures municipality with a substantial potential damage.info:eu-repo/semantics/publishedVersio

    New phototriggers based on coumarins with extended π-systems

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    Comunicação em painel P35 no XXIV Encontro Nacional da Sociedade de Portuguesa de Química, Coimbra, Portugal, 1-3 Julho 2015The present work describes the synthesis of new coumarin derivatives possessing an extended π-system, in order to bathocromically shift the wavelength of maximum absorption, and consequently of photolysis. These compounds were tested as phototriggers of two neurotransmitter amino acids, glycine and β-alanine, at 254, 300, 350 and 419 nm, in a Rayonet RPR-100 photochemical reactor, and the release of the active compound was monitored by HPLC-UV detection, with collection of kinetic data.Fundação para a Ciência e Tecnologia (FCT, Portugal) for financial support to the NMR portuguese network (PTNMR, Bruker Avance III 400-Univ. Minho), FCT and FEDER (European Fund for Regional Development) -COMPETE-QREN-EU for financial support to Research Centre of Chemistry, CQ/UM [PEst-C/QUI/UI0686/2013 (FCOMP -01-0124-FEDER-037302)]info:eu-repo/semantics/publishedVersio

    Photorelease of neurotransmitter amino acids from coumarin derivatives

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    Comunicação em painel QS43 no livro de resumos do XX Encontro Luso-Galego de QuímicaIn this work it is presented the photorelease of two model neurotransmitter amino acids, namely glycine and β-alanine, from two different coumarins. These model neurotransmitters were chosen due to their biological importance as well as their pharmacological activities. The coumarin-amino acid conjugates were irradiated at 245, 300, 350 and 419 nm using a Rayonet RPR-100 photochemical reactor and the release of the active compound was monitored by HPLC-UV detection, with collection of kinetic data.Fundação para a Ciência e a Tecnologia (FCT

    Photorelease of glycine and β-alanine from (7-bromocoumarin-4-yl)methyl cages

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    Comunicação eletrónica a015 no 19th Int. Electron. Conf. Synth. Org. Chem., Novembro 2015.With the goal of evaluating the efficiency of 4-chloromethyl-7-bromocoumarin as phototrigger for amino acid neurotransmitters glycine and β-alanine, the corresponding ester conjugates were synthetized. Their irradiation at different wavelengths (254, 300, 350 and 419 nm) in a Rayonet RPR-100 photochemical reactor, in methanol/HEPES buffer (80:20) was carried out. The photolysis process was followed by HPLC with UV detection. Results will be discussed in comparison with those obtained when 4-chloromethyl-7-aminocoumarin was used in the photorelease of glycine and β-alanine.info:eu-repo/semantics/publishedVersio

    Work–family conflicts, cognitive appraisal, and burnout: testing the mediation effect with structural equation modelling

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    Work-family conflict constitutes an important source of occupational stress predicting teachers’ burnout, and cognitive variables have shown to be core structures in explaining human adaptation to stress. Nevertheless, the role of cognitive appraisal needs to be fully analysed to comprehend how it can mediate the relationship between stress and burnout. In order to understand the potential mediation of cognitive appraisal in the relationship between stress and burnout, we adopted conceptual models of stress that highlighted the value of cognitive appraisal on positive and negative reactions to work demands. Also, we analysed the potential moderation of sex and age in the relationship between work-family conflict, cognitive appraisal, and burnout due inconsistent findings on how these personal variables can interfere on these relations. In this study, we used Structural Equation Modelling (SEM) to test the mediating of cognitive appraisal in the relationship between work-family conflicts and burnout. A survey with measures of work-family conflicts, cognitive appraisal, and burnout was administered to the participants consisting of 438 Portuguese teachers from kindergarten through high school, aged between 28 and 67 years (M = 46.85; SD = 7.88), 304 of whom were females (69.41%). The results confirmed that cognitive appraisal partially mediated the relationship between work-family conflict and burnout. The mediation effect of cognitive appraisal on the relationship between work-family conflict and burnout was invariant regardless of teachers’ sex or age. In sum, cognitive appraisal should be considered in order to understand teachers’ adaptation to work.This study was conducted at the Psychology Research Centre (PSI/01662), School of Psychology, University of Minho, and supported by the Portuguese Foundation for Science and Technology and the Portuguese Ministry of Science, Technology and Higher Education (UID/PSI/01662/2019), through the national funds (PIDDAC). The authors have no conflicts of interest to report

    Exposure to PM2.5 and cardiovascular diseases in Portugal: the contribute of PMCardImpact project

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    Particulate matter with a diameter of 2.5 μm or less (PM2.5) is one of the air pollutants more detrimental to human health, being responsible for around 400 000 premature deaths in Europe every year. Cardiovascular diseases (CVD) and air pollution are linked, with existing evidence of a causal relationship between exposure to particulate matter and cardiovascular morbidity and mortality. Under the scope of PMCardImpact, a nationally funded project, data collected from the Portuguese air monitoring platform (2005-2021) (>60 stations) was used to estimate the attributable number of cases of acute myocardial infarction. The air monitoring data and parameters such as exposure-response factors will support the risk assessment in AirQ+ software (WHO Regional Office for Europe). Preliminary results showed that exceedances of the Air Quality Directive in Portugal ranged between 0.1 % and 10.2% for PM10 and PM2.5 in 2019. Results obtained will include the number of cases of CVD attributable to exposure to PM2.5 in the Portuguese population. Four scenarios of exposure will be considered for presenting the results: the current scenario of exposure, new WHO Air Quality guidelines, the European Commission Air Quality Directive, and lastly, a worst-case scenario. This assessment will be the starting point for calculating the burden of the disease of CVD that exposure to PM2.5 represents in Portugal. With a view to promoting the science-to-policy interface, the PMCardImpact project will make available to policymakers the needed supporting information to act, including actionable knowledge on air pollution trends and related health effects, to implement reducing air pollution policies.info:eu-repo/semantics/publishedVersio

    Large and variable genome size unrelated to serpentine adaptation but supportive of cryptic sexuality in Cenococcum geophilum

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    Estimations of genome size and its variation can provide valuable information regarding the genetic diversity of organisms and their adaptation potential to heterogeneous environments. We used flow cytometry to characterize the variation in genome size among 40 isolates of Cenococcum geophilum, an ectomycorrhizal fungus with a wide ecological and geographical distribution, obtained from two serpentine and two non-serpentine sites in Portugal. Besides determining the genome size and its intraspecies variation, we wanted to assess whether a relationship exists between genome size and the edaphic background of the C. geophilum isolates. Our results reveal C. geophilum to have one of the largest genome sizes so far measured in the Ascomycota, with a mean haploid genome size estimate of 0.208 pg (203 Mbp). However, no relationship was found between genome size and the edaphic background of the sampled isolates, indicating genetic and demographic processes to be more important for shaping the genome size variation in this species than environmental selection. The detection of variation in ploidy level among our isolates, including a single individual with both presumed haploid and diploid nuclei, provides supportive evidence for a possible cryptic sexual or parasexual cycle in C. geophilum (although other mechanisms may have caused this variation). The existence of such a cycle would have wide significance, explaining the high levels of genetic diversity and likelihood of recombination previously reported in this species, and adds to the increasing number of studies suggesting sexual cycles in previously assumed asexual fungi.This work was supported by research grant PTDC/BIA-BEC/100733/2008, funded by the European Union and the Fundação para a Ciência e a Tecnologia, awarded to Ludo Muller
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