Meeting Abstract

P2.34  Monday, Jan. 5  The Acute and Chronic Heat Stress Response in the Purple Sea Urchin, Strongylocentrotus purpuratus: A Proteomics Approach VALENZUELA, J.J.*; TOMANEK, L.; Montana State University – Bozeman; California Polytechnic University – San Luis Obispo jjvalenz@calpoly.edu

Purple sea urchins (Strongylocentrotus purpuratus) inhabit intertidal zones where they experience extreme temperature fluctuations. In this study we used a proteomics approach to characterize the protein expression profiles in response to heat. We acclimated sea urchins to 11C and 18C for four weeks and subsequently exposed animals to 25C for 4 hours. Afterwards animals were brought back to their respective acclimation temperature for a 16 h recovery period. We excised tube feet tissue immediately after recovery and homogenized it in urea-containing buffer. Proteins were separated using two-dimensional gel electrophoresis (2D-GE): first we used an immobilized pH gradient to focus proteins according to their net charge and, second, we used sodium dodecyl sulfate- polyacrylamide gel electrophoresis (SDS-PAGE) to separate proteins according to their molecular weight. Gels were stained with a fluorescent stain and 2D gels were subsequently analyzed using image analysis software (Delta2D) to determine which protein spots are differentially expressed in response to heat. The expression of 28 proteins (7% of 425 total) changed with acute, and of 25 (6%) with chronic (acclimation to 18C) heat stress. 12 (3%) protein spots showed an interaction effect. We are currently using matrix-assisted laser desorption/ionization tandem time-of-flight (MALDI-TOF-TOF) mass spectrometry to identify the differentially expressed proteins. These preliminary results may provide insights into the global response of the sea urchin proteome to environmentally relevant heat stress following different thermal conditions.