Examinando por Materia "Antioxidants"

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    Ítem
    Caracterización de dos metabolitos secundarios aislados de las hojas de Pouteria Caimito
    (Universidad EAFIT, 2012) Aristizábal Cardona, Juan David; Palacios Mosquera, Carlos Mario; Palacio González, Guillermo León
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    Efecto de las Bajas Concentraciones de Nitratos y Fosfatos sobre la Acumulación de Astaxantina en Haematococcus pluvialis UTEX 2505
    (Centro de Informacion Tecnologica, 2019-01-01) Miranda A.M.; Ossa E.A.; Vargas G.J.; Sáez A.A.; Universidad EAFIT. Departamento de Ciencias; Ciencias Biológicas y Bioprocesos (CIBIOP)
    In this study, the effect of the concentration of nitrogen and phosphorus on the accumulation of Astaxanthin in Haematococcus pluvialis UTEX 2505 was evaluated using a factorial 3 2 design. The dependent variables were cell growth, Astaxanthin production, lipid profile and Young's modulus of the cell membrane. It was found that cellular productivity increases when nitrogen levels were high, in contrast to low concentrations of nitrogen and phosphorus that showed a positive effect on Astaxanthin production. The stress generated by the source of nutrients decreases the rigidity of the cellular wall in the microalgae. As a conclusion, to obtain higher concentrations of Astaxanthin it is necessary to limit the nitrogen and phosphorus levels. © 2019 Centro de Informacion Tecnologica. All Rights Reserved.
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    Ítem
    Efecto de las Bajas Concentraciones de Nitratos y Fosfatos sobre la Acumulación de Astaxantina en Haematococcus pluvialis UTEX 2505
    (Centro de Informacion Tecnologica, 2019-01-01) Miranda A.M.; Ossa E.A.; Vargas G.J.; Sáez A.A.; Miranda A.M.; Ossa E.A.; Vargas G.J.; Sáez A.A.; Universidad EAFIT. Departamento de Ingeniería de Producción; Materiales de Ingeniería
    In this study, the effect of the concentration of nitrogen and phosphorus on the accumulation of Astaxanthin in Haematococcus pluvialis UTEX 2505 was evaluated using a factorial 3 2 design. The dependent variables were cell growth, Astaxanthin production, lipid profile and Young's modulus of the cell membrane. It was found that cellular productivity increases when nitrogen levels were high, in contrast to low concentrations of nitrogen and phosphorus that showed a positive effect on Astaxanthin production. The stress generated by the source of nutrients decreases the rigidity of the cellular wall in the microalgae. As a conclusion, to obtain higher concentrations of Astaxanthin it is necessary to limit the nitrogen and phosphorus levels. © 2019 Centro de Informacion Tecnologica. All Rights Reserved.
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    Paracoccidioides spp. catalases and their role in antioxidant defense against host defense responses
    (Elsevier, 2017-03-01) Tamayo, D.; Muñoz, J.F.; Almeida, A.J.; Puerta, J.D.; Restrepo, Á.; Cuomo, C.A.; McEwen, J.G.; Hernández, O.; Universidad EAFIT. Departamento de Ciencias; Ciencias Biológicas y Bioprocesos (CIBIOP)
    Dimorphic human pathogenic fungi interact with host effector cells resisting their microbicidal mechanisms. Yeast cells are able of surviving within the tough environment of the phagolysosome by expressing an antioxidant defense system that provides protection against host-derived reactive oxygen species (ROS). This includes the production of catalases (CATs). Here we identified and analyzed the role of CAT isoforms in Paracoccidioides, the etiological agent of paracoccidioidomycosis. Firstly, we found that one of these isoforms was absent in the closely related dimorphic pathogen Coccidioides and dermatophytes, but all of them were conserved in Paracoccidioides, Histoplasma and Blastomyces species. We probed the contribution of CATs in Paracoccidioides by determining the gene expression levels of each isoform through quantitative RT-qPCR, in both the yeast and mycelia phases, and during the morphological switch (transition and germination), as well as in response to oxidative agents and during interaction with neutrophils. PbCATP was preferentially expressed in the pathogenic yeast phase, and was associated to the response against exogenous H2O2. Therefore, we created and analyzed the virulence defects of a knockdown strain for this isoform, and found that CATP protects yeast cells from H2O2 generated in vitro and is relevant during lung infection. On the other hand, CATA and CATB seem to contribute to ROS homeostasis in Paracoccidioides cells, during endogenous oxidative stress. CAT isoforms in Paracoccidioides might be coordinately regulated during development and dimorphism, and differentially expressed in response to different stresses to control ROS homeostasis during the infectious process, contributing to the virulence of Paracoccidioides. © 2017 Elsevier Inc.