Meeting Abstract

S6-2.2  Thursday, Jan. 5  Mechanisms of acclimation to pollutants and elevated temperature in aquatic organisms. Changes of the cellular phenotype revealed by proteomics. SILVESTRE, Frederic; University of Namur

Acclimation, in contrast to evolutionary adaptation, can be defined as a “within lifetime” phenotypic adaptation to an environmental parameter involving a suite of adjustments that allow an organism to shift its optimum for numerous physiological activities to new range. As cellular phenotype, a proteome can be adjusted during the acclimation process. Whereas proteomic response to acute stress has been largely studied, only little attention has been given so far to acclimation mechanisms. Here we present protein expression profile changes in different aquatic species, the Chinese mitten crab Eriocheir sinensis, the bullhead fish Cottus gobio, and the least killifish Heterandria formosa, after acclimation to mild elevated temperature or exposure to pollutants (cadmium and copper). Physiological, biochemical or lethality assays enabled the determination of the acclimation window for the studied stressors. After 2D-PAGE protein separation and mass spectrometry-based identification, two proteomes have been distinguished for each acclimation condition. The first one corresponds to a "general stress proteome" which encompasses the most abundant proteins usually differentially expressed under a stressful condition. Secondly, a specific proteome could be defined for each stress condition, and likely represents the cellular responses to specific mode of action. When cross-tolerance is observed, e.g. between elevated temperature and exposure to cadmium, those proteomic signatures can bring clues to understand shared mode of action. The different roles of a general and a specific response are discussed. These acquired traits at a proteomic level can be involved in a rapid form of adaptive evolution.