A5015138948- Redox biology and oxidative stress
- Genomics, phytochemicals, and oxidative stress
- Nitric Oxide and Endothelin Effects
- Sulfur Compounds in Biology
- Free Radicals and Antioxidants
- Mitochondrial Function and Pathology
- Metal-Organic Frameworks: Synthesis and Applications
- Nanoplatforms for cancer theranostics
- Electron Spin Resonance Studies
- bioluminescence and chemiluminescence research
- Microbial Metabolic Engineering and Bioproduction
- Fungal and yeast genetics research
- Coenzyme Q10 studies and effects
- Lipid Membrane Structure and Behavior
- Antioxidant Activity and Oxidative Stress
- Mesoporous Materials and Catalysis
- Electrochemical Analysis and Applications
- thermodynamics and calorimetric analyses
- Bone Tissue Engineering Materials
- Immune Response and Inflammation
- Lipid metabolism and biosynthesis
- Photosynthetic Processes and Mechanisms
- Catalytic Processes in Materials Science
- Eicosanoids and Hypertension Pharmacology
- Magnesium Oxide Properties and Applications
University of Lisbon
2015-2024
Rede de Química e Tecnologia
2004-2017
Instituto Politécnico de Lisboa
2015-2016
Faculdade de Tecnologia e Ciências
2015-2016
Lusíada University of Lisbon
2015
Instituto de Investigação Científica Tropical
1995-2009
University of Buenos Aires
2000-2004
University of Southern California
1999-2003
Linköping University
2003
Duke University
2002
Several reactions in biological systems contribute to maintain the steady-state concentrations of superoxide anion (O 2⨪) and hydrogen peroxide (H2O2). The electron transfer chain mitochondria is a well documented source H2O2; however, release O 2⨪ from into cytosol has not been unequivocally established. This study was aimed at validating as sources cytosolic 2⨪, elucidating mechanisms underlying cytosol, assessing role outer membrane voltage-dependent channels (VDACs) this process....
When cells are exposed to an external source of H 2 O , the rapid enzymatic consumption inside cell provides driving force for formation gradient across plasma and other subcellular membranes. By using concepts enzyme latency, following gradients – formed after a few seconds exposure were estimated in Jurkat T‐cells: [H ] cytosol /[H peroxisomes =3; extracellular =7. The procedure presented this work can easily be applied lines quantitative framework interpret data obtained when .
Exposure of mammalian cells to oxidant stress causes early (iron catalysed) lysosomal rupture followed by apoptosis or necrosis. Enhanced intracellular production reactive oxygen species (ROS), presumably mitochondrial origin, is also observed when are exposed nonoxidant pro‐apoptotic agonists cell death. We hypothesized that ROS generation in this latter case might promote the apoptotic cascade and could arise from effects released materials on mitochondria. Indeed, intact (J774...
We have re-examined the lysosomal hypothesis of oxidative-stress-induced apoptosis using a new technique for exposing cells in culture to low steady-state concentration H2O2. This mimics situation vivo better than bolus-administration method. A key aspect H2O2-induced is that evident only after several hours, although may become committed within few minutes exposure this particular reactive oxygen species. In present work, we were able show, first time, correlative links between triggering...
The detailed molecular mechanism for the reversible inhibition of mitochondrial respiration by NO has puzzled investigators: rate constants binding and O 2 to reduced binuclear center Cu B /a 3 cytochrome oxidase (COX) are similar, is able dissociate slowly from this whereas kinetically trapped, which altogether seems favor complex COX with over NO. Paradoxically, observed at high ratios (in 40–500 range) very fast (seconds or faster). In work, we used simple mathematical models investigate...
In this study, we propose a method for quantification of average hydrogen peroxide concentration within living cell that is based on the use genetically encoded H2O2 biosensor HyPer. The utilizes flow cytometric measurements HyPer fluorescence in H2O2-exposed cells to analyze oxidation kinetics. Fitting experimental curves with kinetic equations allows determining rate constants oxidation/reduction which are used further calculation concentrations interest both presence and absence external...
Reactive oxygen species (ROS), including H2O2, contribute to oxidative stress and may cause cancer initiation progression. However, at low concentrations, H2O2 can regulate signaling pathways modulating cell growth, differentiation, migration. A few mammalian aquaporins (AQPs) facilitate diffusion across membranes participate in tumorigenesis. AQP3 AQP5 are strongly expressed tissues AQP3-mediated transport has been related breast migration, but studies with human lacking. Here, we report...
Abstract Materials for the controlled release of nitric oxide (NO) are interest therapeutic applications. However, to date, many suffer from toxicity and stability issues, as well poor performance. Herein, we propose a new NO adsorption/release mechanism through formation nitrites on skeleton titanium‐based metal–organic framework (MOF) that named MIP‐177, featuring suitable set properties such an application: (i) high storage capacity (3 μmol mg −1 solid ), (ii) excellent biocompatibility...
We have re-examined the lysosomal hypothesis of oxidative-stress-induced apoptosis using a new technique for exposing cells in culture to low steady-state concentration H2O2. This mimics situation vivo better than bolus-administration method. A key aspect H2O2-induced is that evident only after several hours, although may become committed within few minutes exposure this particular reactive oxygen species. In present work, we were able show, first time, correlative links between triggering...
Contrary to what is widely believed, recent published results show that H2O2 does not freely diffuse across biomembranes. The fast removal of by antioxidant enzymes able generate a gradient if produced in different compartment from containing the (Antunes, F., and Cadenas, E. (2000) FEBS Lett. 475, 121-126). In this work, we extended these studies tested whether an active regulation biomembranes permeability characteristics part cell response oxidative stress. Using Saccharomyces cerevisiae...
Abstract Although the germicide role of H2O2 released during inflammation is well established, a hypothetical regulatory function, either promoting or inhibiting inflammation, still controversial. In particular, after 15 years highly contradictory results it remains uncertain whether by itself activates NF-κB if stimulates inhibits activation proinflammatory mediators. We investigated in using, for first time, calibrated and controlled method delivery—the steady-state titration—in which...
The plasma membrane of Saccharomyces cerevisiae was studied using the probes trans-parinaric acid and diphenylhexatriene. Diphenylhexatriene anisotropy is a good reporter global order. fluorescence lifetimes are particularly sensitive to presence nature ordered domains, but thus far they have not been measured in yeast cells. A long lifetime typical gel phase (>30 ns) found wild-type (WT) cells from two different genetic backgrounds, at 24 30 °C, providing first direct evidence for domains...
Aquaporin-5 (AQP5) is a membrane water channel widely distributed in human tissues that was found up-regulated different tumors and considered implicated carcinogenesis organs systems. Despite its wide distribution pattern physiological importance, AQP5 short-term regulation not reported mechanisms underlying involvement cancer are well defined. In this work, we expressed rat yeast investigated of gating, as AQP5's ability to facilitate H₂O₂ plasma diffusion. We can be gated by extracellular...
The higher resistance of stationary‐phase Saccharomyces cerevisiae to H 2 O when compared with exponential phase is well characterized, but the molecular mechanisms underlying it remain mostly unknown. By applying steady‐state ‐delivery model, we show that (a) cellular permeability five times lower in stationary – than phase; (b) cell survival correlates gradients for a variety cells; and, (c) cells are predicted be more susceptible intracellular phase. In conclusion, limiting diffusion into...