Presented by: Andrea Morash, Postdoctoral Fellow, University of Cambridge, UK and Fathima I. Iftikar, PhD Candidate, University of Auckland, New Zealand
Abstract 1: Environmental stress is often met with changes in metabolism to compensate for increased energetic demand. The extent and magnitude of these changes may underpin the success or failure of species to adapt in various environments. Lipid metabolism, in particular is a fundamental component of most living organisms and plays a role in energy homeostasis, molecular signalling, and cell structure. Lipids are a primary form of energy storage for most vertebrates and also fuel the majority of aerobic ATP production to support ATP consuming reactions. The evolution and regulation of lipid metabolism will be discussed with a particular emphasis on development and coping with physiological stresses such as starvation and exercise in a variety of fish species. I propose that fish have a unique metabolic plasticity over other vertebrates, which allows them to thrive under diverse environmental conditions
Biography: Andrea completed her PhD in Comparative Physiology in 2010 at McMaster University, Canada on the evolution and regulation of mitochondrial lipid oxidation. Using a diverse range of fish and mammalian species she identified key regulatory points in the lipid metabolism pathway and how they transformed under a variety of physiological and environmental stresses to enable maximal energetic efficiency. Andrea is now a postdoctoral fellow at the University of Cambridge, UK, and holds a Natural Science and Engineering Research Council of Canada (NSERC) Postdoctoral Fellowship. Her current research focuses on mitochondrial metabolism and fuel selection during hypoxia in cardiac and skeletal muscle. Andrea’s research uses a range of techniques; from whole animal down to molecular biology and encompasses the fields of physiology, ecology, evolution and health and disease.
Abstract 2: In aquatic species, the heart is extremely temperature sensitive, and often the critical temperature for heart failure (HF) is only a few degrees above species’ upper habitat temperatures (Tmax). Predictions of climate change mediated rises in ocean temperatures also suggest that ectothermic hearts may constrain many marine species distributions. HF at high temperature may result from disrupted ion transport, oxygen and substrate supply disruptions to and from energy supplying mitochondria in cardiac cells. My PhD study targets mitochondria, as damaged mitochondria may increase their reactive species production and trigger apoptosis, or they may fail to produce enough ATP to sustain a heartbeat. Using an endemic New Zealand fish species, Notolabrus celidotus, or “the Spotty”, we assessed cardiac function and determined the THF. We then used high-resolution respirometers to explore temperature-mediated changes in cardiac mitochondrial function and ROS production, and overlaid these changes with that of heart function and THF. Data from my study suggests that mitochondrial function and integrities could play a significant role in thermal stress tolerance and perhaps limit species distributions.
Biography: Fathima did her undergraduate and masters studies at McMaster University, Hamilton ON Canada in Dr. Chris Wood’s lab. She studied ‘the osmorespiratory compromise’ in hypoxia-tolerant and intolerant freshwater fish during her masters. Fathima is currently doing her PhD at the University of Auckland, in Dr. Anthony Hickey’s lab studying the effects of heat stress on heart and mitochondrial failure in marine fish from a climate change perspective.