Meeting Abstract

P2.35  Monday, Jan. 5  Temperature acclimation has a greater effect than heat shock on gill protein expression patterns in two congeners of blue mussel (genus Mytilus) CLAUSEN, R.C.**; FIELDS, P.A.; TOMANEK, L.; Franklin and Marshall College; Franklin and Marshall College; Cal Poly San Luis Obispo peter.fields@fandm.edu

We used proteomic techniques to compare protein expression profiles of gill tissue from two blue mussel congeners, Mytilus galloprovincialis (Mg) and M. trossulus (Mt). The former is invasive along the coast of southern California, and has replaced the latter, native congener there, perhaps due to greater heat tolerance. After acclimating each species to 7 or 13C for 3 wk, we exposed 6 treatment individuals to a heat shock (HS) of 32C for 1 h, followed by 24 h of recovery at acclimation temperature (AT). Six control (no-HS) individuals were sacrificed after acclimation. 2D gel electrophoresis was performed on gill protein extracts, and protein expression profiles from 48 gels (6 replicates x 2 species x 2 AT x 2 treatments) were analyzed using Delta2D software (Decodon). Over 1000 protein spots were found and associated across all gels. Using a variety of analytical tools, including ANOVA, hierarchical clustering, and principle components analysis, we found that the two species differ in protein expression pattern, regardless of AT. Further, within each species, there are significant differences in protein expression between individuals acclimated to 7C compared to those acclimated to13C. However, HS had a weaker effect than acclimation on protein expression: Mg control and HS individuals showed little difference in protein expression (i.e, these two groups did not cluster separately), while protein expression profiles of Mt control and HS individuals showed discernable clustering, but not of the magnitude found between 7C- and 13C-acclimated individuals. These data suggest that, in Mytilus congeners, long-term acclimation may have a greater effect on tissue-wide protein expression profiles than does HS, and that Mg is relatively less sensitive to HS than Mt.