Browsing by Subject "Mistletoe"

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    Antifungal effects and mechanism of action of viscotoxin A3
    (Federation of European Biochemical Societies [Society Publisher], 2006-01-01) Guidici Besseghini, Ana Marcela; Poveda Larrosa, José Antonio; Molina Gallego, María Luisa; Canal, Laura de la; González Ros, José Manuel; Pfüller, Karola; Pfüller, Uwe; Villalaín Boullón, José; Bioquímica y Biología Molecular B e Inmunología
    Viscotoxins are cationic proteins, isolated from different mistletoe species, that belong to the group of thionins, a group of basic cysteine-rich peptides of ≈ 5 kDa. They have been shown to be cytotoxic to different types of cell, including animal, bacterial and fungal. The aim of this study was to obtain information on the cell targets and the mechanism of action of viscotoxin isoform A3 (VtA3). We describe a detailed study of viscotoxin interaction with fungal-derived model membranes, its location inside spores of Fusarium solani, as well as their induced spore death. We show that VtA3 induces the appearance of ion-channel-like activity, the generation of H2O2, and an increase in cytoplasmic free Ca2+. Moreover, we show that Ca2+ is involved in VtA3-induced spore death and increased H2O2 concentration. The data presented here strongly support the notion that the antifungal activity of VtA3 is due to membrane binding and channel formation, leading to destabilization and disruption of the plasma membrane, thereby supporting a direct role for viscotoxins in the plant defence mechanism.
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    Contribución al estudio de las poblaciones de Viscum album L. subsp. Austriacum (Wiesb.) Vollman en masas forestales de la provincia de Ávila (España)
    (Murcia: Universidad de Murcia, Servicio de Publicaciones, 1992) López-Sáez, J.A.; Facultad de Biología
    Se estudia la presencia y distribución del muérdago en la provincia de Ávila sobre un total de cuatro hospedantes. Se presentan así mismo algunas características ecológicas y biológicas de la hemiparásita en bosques abulenses.
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    Dietary mistletoe lectin supplementation and reduced growth of a murine non-Hodgkin lymphoma
    (Murcia : F. Hernández, 2002) Pryme, I.F.; Bardocz, S.; Pusztai, A.; Ewen, S.W.B.
    The growth of a murine non-Hodgkin lymphoma (NHL) tumour has been shown to be reduced by incorporating mistletoe lectin (ML-1) into the diet. The morphological characteristics of NHL tumours in mice fed ML-1-supplemented diets were different from those in LA (control)-fed mice. The degree of mitotic activity was lower and nuclear area reduced. The degree of lymphocyte infiltration was increased in tumours from ML-1 fed mice and this was accompanied by a high incidence of apoptotic bodies. Visual observation of NHL tumours from individuals fed ML-1 diet showed a poorly developed blood supply in contrast to control-fed mice. A major reduction in number of blood capillaries in NHL tumours was confirmed by microscopic evaluation of tumour sections. The results suggested an anti-angiogenic response in ML-1-fed mice. The feeding of ML-1 compared to control diet thus provided several identifiable changes in the morphology of NHL tumours which were consistent with the observed reduction in tumour weight. There was no longer histological evidence of viable tumour in 25% mice fed the ML-1 diet for 11 days. Morphological studies of the small bowel indicated (a) that the lectin induces hyperplasia, and (b) that the lectin binds avidly to lymphoid tissue of P e y e r’s patches. There was evidence of limited endocytosis of the lectin. An experiment where ML-3 was added to the diet of mice three days after inoculation of tumour cells showed that the lectin was able to slow down further growth of an established tumour. The results show that ML lectins induce powerful anti-cancer effects when provided by the oral route.