COSC 9th Meeting
June 1st -3rd, 2016
University of Guelph
Departamento de Bioquímica
Instituto de Química – Universidade de São Paulo
Dr. Kowaltowski is a prominent researcher in the field of free radical biology. She frequently chairs major meetings including the recent Gordon Research Conference on Oxygen Radicals: From Detection to Disease. Her research focuses on changes in mitochondrial energy metabolism, ion transport, and redox state are associated with a variety of physiological and pathological conditions including aging, obesity and heart attack. The central aim of this research group is to analyze the role of these alterations in physio-pathological conditions. A better understanding of the molecular mechanisms underlying the mitochondrial involvement in these processes will allow the development of interventions capable of controlling these unwelcome effects.
Mitochondria, the flexible
We will discuss how mitochondrial form and function are altered in caloric restriction, a dietary intervention that enhances lifespan and health span. Caloric restriction protects the brain against excitotoxic stimuli by increasing Ca2+ uptake in mitochondrial. Caloric restriction also regulates insulin release by modulating islet mitochondrial dynamics. Finally, mitochondrial morphological changes are central for the differentiation of stem cells. Overall, our results show that mitochondrial form and function are intimately interconnected, and present central regulatory roles in energy metabolism.
Professor in Plant Science
School of Biology
University of Leeds, UK
The Foyer lab is interested in the regulation of growth and development under optimal and stress (drought, chilling, high light, aphid infestation) conditions, with a particular focus on how cellular reduction/oxidation (redox) homeostasis and signalling interact with phytohormone–mediated pathways, particularly involving abscisic acid, auxin and stigolactones. Research focuses on ascorbate and glutathione as key regulators of plant responses to stress and on how redox processes associated with primary metabolism particularly photosynthesis and respiration regulate gene expression. Dr. Foyer directs the Human Health and Food Security Project in sub-Saharan Africa. Foyer’s name is included in the “Foyer-Halliwell-Asada” pathway, a cellular process of hydrogen peroxide metabolism in plants and animals.
Glutathione: From the chloroplast to the nucleus
The low molecular weight thiol antioxidant, reduced glutathione (GSH) is a multifunctional metabolite in plants. GSH is an important redox gatekeeper that maintenance redox homeostasis. It also participates in oxidative signalling pathways that regulate gene expression and determine the outcome of plant responses to stress. GSH is synthesised in chloroplasts, from thence is transported to all the compartments of the cell including the nucleus. Inhibition of glutathione synthesis leads to decreases the redox potential of the cytosol and the nuclei and to marked changes in gene expression. Low GSH availability leads to failure of the apical root meristem because of an arrest of the cell cycle at G1. GSH is recruited and sequestered in the nucleus early in the cell cycle by mechanisms that remain to be identified. The glutathione redox potential of the nuclei of root tip cells determined using redox-sensitive (ro-) green fluorescent protein was found to be the same at that of the cytosol (-295 +/- 2.5 mV). Using 3mM hydroxyurea to synchronise the cell cycle, we have followed the redox changes occurring in proliferating plant cells at the various stages of the cell cycle. Data will be presented showing that the glutathione redox potentials of the nuclei become more oxidised relative to the cytosol under different conditions.