The proposed research seeks to elucidate the biochemical mechanisms by which cells acclimate to changes in the osmolarity of their external environment. The focus of the work will be on the regulation of proline accumulation in response to salinity change in an intertidal marine crustacean which frequently encounters such environmental changes. Previous work has shown that proline is synthesized by the organism only in response to salinity increases; experiments will now determine the metabolic step at which this regulation is exerted and the mechanism by which the regulation is achieved. While many marine organisms are known to accumulate proline in response to elevated salinity, the metabolic site and mechanism of the regulation of this response has never been demonstrated. A second aspect of the research focusses on the influence of genetic variation on salinity response. Previous work has shown that some of the enzymes involved in synthesizing free amino acids during salinity response are genetically variable. By studying the physiology of different enzyme genotypes experiments will determine if this genetic variation is important in the adaptation of organisms to different salinity environments. Potential applied aspects of the project involve the use of genetic variation at specific enzyme encoding gene loci for the development of salt tolerant crustaceans for aquaculture.
