Meeting Abstract

1.9  Monday, Jan. 4  Proteomic analysis of acute salinity stress in the two ascidian species Ciona savignyi and C. intestinalis KOMAN, James S.*; TOMANEK, Lars; Cal Poly SLO jskoman@gmail.com

The ascidian species Ciona savignyi and C. intestinalis have been fully sequenced and thus allow analysis of their proteomic response to environmental stress. We have chosen to analyze their response to hyposaline conditions, which are known to occur during heavy winter rains in the coastal regions in which Ciona populations live. Such conditions often lead to population declines and it has been suggested that it may contribute to determining the life history of these species along the West coast of North America. Testing for their proteomic response to salinity may provide insights into the mechanisms that are responsible for setting tolerance limits to hyposaline conditions in these two congeneric species. Characterizing the proteomic response to acute salinity and other stresses also contributes to our understanding of the minimal stress proteome, which we are characterizing for these species. We exposed each species to decreasing salinities, 100%, 85% and 70% full-strength seawater, for 6 hours. After exposure to hyposaline conditions, the specimens were brought back to 100% seawater to recover for 4 hours. Organisms were dissected to remove the tunic, and 2D SDS-PAGE was performed to separate proteins and characterize changes in protein expression. Using a 2D gel image analysis software we identified 5% and 19% of the detected proteins to be differentially expressed in C. savignyi and C. intestinalis, respectively, in response to acute salinity stress in the treatment in comparison to the control group. Analysis of these proteins with MALDI TOF-TOF mass spectrometry has identified numerous cytoskeletal and general stress response proteins, providing insights into the intense cellular and cytoskeletal restructuring that occurs in response to hyposaline exposure.