Meeting Abstract

143.3  Monday, Jan. 7  Myocardial stress and Myoglobin expression in cardiac tissue of Hypoxic and Hyperoxic reared Alligator mississippiensis (A.m.) PARRILLA, L.*; OWERKOWICZ, T.; OMORI, M.; HICKS, J.; ROURKE, B.; California State University, Long Beach; California State University, San Bernardino; California State University, Long Beach; University of California, Irvine; California State University, Long Beach leah.parrilla@student.csulb.edu

We use Alligator mississippiensis (A.M.) as a model species of longevity and adaptability. Incubated A.M. eggs were raised in oxygen conditions of 16%, 21%, 26%, 31%, and 36% representative of oxygen levels over the last 500my. We hypothesized that A.m. raised in hypoxic environments would have constraints on cardiovascular load thus increasing oxygen related protein expression and myosin heavy-chain (MyHC) plasticity related to cardiovascular demands. Heart was examined at embryonic, hatchling and post-hatchling time points as indicators of phenotypic plasticity to differing oxygen environments. No differences in MyHC expression were found between hypoxic and hyperoxic treatment groups although typical growth related shifts from fast contracting alpha isoforms to the slower more economical beta isoforms were seen only in right atria. Myoglobin (Mb), a major oxygen storage protein in cardiac muscle was identified in the hyperoxic treatment groups using 2-D proteomic analysis. Hyperoxic alligators also expressed heat shock proteins 70A, 70B, and 27 suggesting increased loading as a contributor to myocardial stress. Additional identification and quantification using SDS-PAGE mini gels combined with mass spectroscopy found hypoxic treatment groups were expressing significantly higher levels of Mb in the right ventricle. Mb may be contributing to a compensatory response in hypoxic alligators. Funded by NSF grant:IOS-0922627 NSF RUI