Meeting Abstract

97.6  Wednesday, Jan. 7  The proteome response of Mytilus congeners to salinity stress TOMANEK, L.*; VALENZUELA, J. J.; HITT, L. R.; California Polytechnic State University, San Luis Obispo; California Polytechnic State University, San Luis Obispo; California Polytechnic State University, San Luis Obispo ltomanek@calpoly.edu

The marine mussel Mytilus galloprovincialis is an invader along the Pacific coast of North America and competes with the native M. trossulus. Interspecific differences in temperature and salinity tolerance are thought to contribute to limiting their distribution ranges and to determining the competitive advantages of the two congeners. Of the two species, M. trossulus is more tolerant towards low salinities in comparison to M. galloprovincialis. Here we studied the global changes in protein expression of both congeners in response to hyposaline stress using two-dimensional gel electrophoresis and mass spectrometry. Exposure to hyposaline conditions (85% and 70% sea water) for 4 h and subsequent recovery at a 100% for 24 h led to greater changes in global protein expression in gill tissue in M. trossulus (11% of the 477 detected protein spots) than in M. galloprovincialis (6%). After cluster analysis of the expression profiles we found that these differences are mainly due to a smaller number of proteins being down-regulated in M. galloprovincialis. In contrast, the number of proteins that were up-regulated in response to hyposaline stress was similar (15 versus 16) for both congeners. Half of those spots have the same molecular mass and isoelectric point on a 2D gel image in both species. Principal component analysis shows that the protein response to hyposaline conditions is much more distinct in M. trossulus than in M. galloprovincialis. We are currently using matrix-assisted laser desorption ionization (MALDI) – tandem time-of-flight mass spectrometry to identify proteins of interest.