P3-117 Sunday, Jan. 6 15:30 - 17:30 Reactive oxygen species and their role in H2S toxicity in Poecilia mexicana NIEVES, NA*; ARNER, A; TOBLER, M; BARTS, N; Kansas State University; Penn State University; Kansas State University; Kansas State University email@example.com
Extreme environments are characterized by physiochemical stressors that adversely affect biological processes within organisms. Organisms that inhabit these environments have evolved physiological adaptations that allow them maintain function in the presence of stressors. Poecilia mexicana, an extremophile fish that inhabits hydrogen sulfide (H2S)-rich environments, is an ideal system to study how organisms modify physiological processes in response to an environmental stressor. H2S is a naturally occurring toxin in these springs that reversibly binds to cytochrome c oxidase (COX) in the mitochondrial respiratory chain, inhibiting aerobic ATP production. COX is normally responsible for capturing the reactive oxygen species (ROS), which are capable of causing cellular damage. In the presence of H2S, however, COX is incapable of accepting electrons, ultimately resulting in increased production of ROS. Some sulfide-tolerant populations of P. mexicana possess a modified COX that allow them to maintain ATP production and maintain cellular function in the presence of H2S, while other sulfide-tolerant – and sulfide-intolerant – populations and an additional population do not. We predict that upon exposure to environmental H2S, concentration of reactive oxygen species should be higher in fish that lack a sulfide-tolerant modified COX. Additionally, we predict that lipid peroxidation, damage used to assess the negative effects of ROS on cells should also be higher in these same populations. Preliminary data shows that there is a significant effect of H2S exposure on ROS production in the liver, but not brain or gill. The data collected in this project will provide further understanding on the role of ROS in H2S toxicity.