Meeting Abstract

P2.111  Wednesday, Jan. 5  Rates of mitochondrial H₂O₂ production and non-heme iron contents in selected tissues from cold- and warm-acclimated striped bass (Morone saxatilis) WHEELER, MS*; KELLEY, K; TAPLEY, DW; CROCKETT, EL; Salem State University; University of Maine, Farmington; Salem State University; Ohio University and MDI Biological Laboratory m_wheeler2@salemstate.edu

Ectotherms living in cold water face several environmental and physiological challenges, including higher levels of oxygen and polyunsaturated fatty acids with an abundance of mitochondria, when compared to animals in warmer water. We investigated whether content of the potential pro-oxidant, non-heme iron (Fe) varies with acclimation temperature and if acclimation temperature alters the extent to which mitochondria produce reactive oxygen species (ROS). Striped bass (Morone saxatilis) were acclimated for a minimum of one week to 9.5°C and 21°C. Production of hydrogen peroxide by glycolytic muscle mitochondria was monitored using Amplex UltraRed over a period of 3 hours at 15°C. When normalized to either mitochondrial protein or units of cytochrome c oxidase activity, rates of ROS production (with the substrate succinate) were not statistically different for mitochondria prepared from cold- or warm-acclimated fish. Not surprisingly, spleen possesses the highest levels of Fe, followed by liver and cardiac muscle, which both contained 1-3 times more Fe than skeletal muscle. Cardiac muscle from cold-acclimated fish showed a 2.2-fold increase in non-heme iron levels compared to the warm-acclimation group. These results indicate that at physiological temperatures mitochondria from warm-bodied animals may produce higher levels of ROS than mitochondria from animals at cold temperatures. On the other hand, hearts from cold-acclimated fish may be more vulnerable to oxidative injury because of the higher levels Fe. Supported by NSF-IOS 0842624. crockett@ohio.edu