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Browsing by Issue Date, starting with "2023-03-21"

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  • A arte dos dólmenes e a arte contemporânea: reminiscências e anacronismos
    Publication . Ceriz, Ernesto Jorge Ferreira; Carvalho, António Manuel Faustino de
    O presente trabalho decorre de uma pesquisa sobre o fenómeno da designada “Arte Dolménica”, a qual encerra um código imagético que é estrito da prática funerária das sociedades neolíticas construtoras dos dólmenes, a qual ocorreu ao longo de todo o IVº e princípios do IIIº milénio A.C.. A par dessa pesquisa, operou-se uma abordagem a esta temática numa perspetiva em que o fator temporal, percebido agora numa dinâmica flexível e não cronológica, pode conduzir ao ressurgimento da imagem de épocas remotas, ainda que revestida de novas formas, na Arte Moderna e na Arte Contemporânea. A forma como abordamos determinado tipo de arte do passado, nomeadamente a Arte Dolménica, e a relacionamos com expressões artísticas do Modernismo e da Contemporaneidade, decorre de uma atitude recetiva face a certos fenómenos que fazem parte da dinâmica do pensamento, como o são a reminiscência e o anacronismo.
    2023-03-21Master thesis Open Access Show more
  • Quick decline and stem pitting Citrus tristeza virus isolates induce a distinct metabolomic profile and antioxidant enzyme activity in the phloem sap of two Citrus species
    Publication . Dandlen, Susana; Da Silva, José Paulo; Miguel, Maria Graca; Duarte, Amilcar; Power, Deborah; Marques, Natália
    Susceptibility to the severe Citrus tristeza virus (CTV), T36, is higher for Citrus macrophylla (CM) than for C. aurantium (CA). How host-virus interactions are reflected in host physiology is largely unknown. In this study, the profile of metabolites and the antioxidant activity in the phloem sap of healthy and infected CA and CM plants were evaluated. The phloem sap of quick decline (T36) and stem pitting (T318A) infected citrus, and control plants was collected by centrifugation, and the enzymes and metabolites analyzed. The activity of the antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT), in infected plants increased significantly in CM and decreased in CA, compared to the healthy controls. Using LC-HRMS2 a metabolic profile rich in secondary metabolites was assigned to healthy CA, compared to healthy CM. CTV infection of CA caused a drastic reduction in secondary metabolites, but not in CM. In conclusion, CA and CM have a different response to severe CTV isolates and we propose that the low susceptibility of CA to T36 may be related to the interaction of the virus with the host’s metabolism, which reduces significantly the synthesis of flavonoids and antioxidant enzyme activity.
    2023-03-21Journal article Open Access Show more