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Projeto de investigação
ALICE - Associate Laboratory in Chemical Engineering
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Publicações
Cardiolipin Membranes Promote Cytochrome c Transformation of Polycyclic Aromatic Hydrocarbons and Their In Vivo Metabolites
Publication . Lopes, João; Marques-da-Silva, Dorinda; Videira, Paula A.; Samhan-Arias, Alejandro K.; Lagoa, Ricardo; UCIBIO - Applied Molecular Biosciences Unit; MDPI - Multidisciplinary Digital Publishing Institute
The catalytic properties of cytochrome c (Cc) have captured great interest in respect to mitochondrial physiology and apoptosis, and hold potential for novel enzymatic bioremediation systems. Nevertheless, its contribution to the metabolism of environmental toxicants remains unstudied. Human exposure to polycyclic aromatic hydrocarbons (PAHs) has been associated with impactful diseases, and animal models have unveiled concerning signs of PAHs’ toxicity to mitochondria. In this work, a series of eight PAHs with ionization potentials between 7.2 and 8.1 eV were used to challenge the catalytic ability of Cc and to evaluate the effect of vesicles containing cardiolipin mimicking mitochondrial membranes activating the peroxidase activity of Cc. With moderate levels of H2O2 and at pH 7.0, Cc catalyzed the oxidation of toxic PAHs, such as benzo[a]pyrene, anthracene, and benzo[a]anthracene, and the cardiolipin-containing membranes clearly increased the PAH conversions. Our results also demonstrate for the first time that Cc and Cc–cardiolipin complexes efficiently transformed the PAH metabolites 2-hydroxynaphthalene and 1-hydroxypyrene. In comparison to horseradish peroxidase, Cc was shown to reach more potent oxidizing states and react with PAHs with ionization potentials up to 7.70 eV, including pyrene and acenaphthene. Spectral assays indicated that anthracene binds to Cc, and docking simulations proposed possible binding sites positioning anthracene for oxidation. The results give support to the participation of Cc in the metabolism of PAHs, especially in mitochondria, and encourage further investigation of the molecular interaction between PAHs and Cc.
Removal of Hydrophobic Organic Pollutants and Copper by Alginate-Based and Polycaprolactone Materials
Publication . Marques-da-Silva, Dorinda; Lopes, João M.; Correia, Iris; Silva, João S.; Lagoa, Ricardo; UCIBIO - Applied Molecular Biosciences Unit; MDPI - Multidisciplinary Digital Publishing Institute
Organic pollutants (OPs) and heavy metals are environmental toxicants associated with great concerns. Decontamination processes are urgent for both, and the possibility to achieve their simultaneous removal from polluted waters is highly interesting. Additionally, in many cases, the effect of organic matter in the removal process is overlooked and must be considered. This work aimed to study the potential of alginate-based and polycaprolactone (PCL) materials to remove OPs and copper ions in the absence and presence of organic matter. The OPs investigated were the polycyclic aromatic hydrocarbons anthracene and benzo[a]pyrene, and the pesticide chlorpyrifos, both hydrophobic compounds. Copper (II) ions were used as a model of heavy metals. Alginate-based spheres were prepared by gelation, and PCL microparticles were obtained by oil/water emulsion solvent evaporation. The materials with the highest efficiencies for OP removal from aqueous solutions were those with activated carbon and PCL. Furthermore, the spheres with activated carbon could remove anthracene and copper simultaneously, even in the presence of humic acid. This work points to activated carbon–alginate spheres as a multifunctional adsorbent able to remove different pollutants and to PCL for potential applications in OP decontamination processes.
Analytical study of the annular flow of a generalised Phan-Thien–Tanner fluid
Publication . Ribau, A. M.; Ferrás, L. L.; Morgado, M. L.; Rebelo, M.; Pinho, F. T.; Afonso, A. M.; DM - Departamento de Matemática; CMA - Centro de Matemática e Aplicações; Springer-Verlag Wien
The annular flow of complex viscoelastic fluids, described by the generalised Phan-Thien–Tanner model, is studied. This model considers the Mittag-Leffler function instead of the usual linear or exponential functions of the trace of the stress tensor, and includes two new parameters that provide additional fitting flexibility. We derive a semi-analytical solution that provides a better understanding of the behaviour of this type of fluid in annular flows and also helps to improve the modelling of complex materials.
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Entidade financiadora
Fundação para a Ciência e a Tecnologia
Programa de financiamento
6817 - DCRRNI ID
Número da atribuição
LA/P/0045/2020