Meeting Abstract

P1.52  Saturday, Jan. 4 15:30  Are molecular chaperone proteins used during salinity adaptation in the ribbed mussel? KAPPER, M.A.; Central Connecticut State University kapper@ccsu.edu

One of the most important abiotic stressors faced by osmoconforming estuarine invertebrates is the tidal fluctuation of environmental salinity. As environmental salinity changes, these organisms adapt by modifying intracellular free amino acid concentrations so that the intracellular osmotic concentration matches that of the environment. This process takes time. The interim osmotic changes of the cytoplasm before complete adaptation is achieved can potentially disrupt the functioning of cellular proteins with severe consequences to homeostasis. There must be a mechanism to maintain protein conformation and function during the process of salinity adaptation. Constitutive heat shock proteins like hsp(73) act as molecular chaperones, modulating folding during translation ensuring proper conformation of the nascent proteins. Induced chaperone proteins like hsp(72) are synthesized during times of stress, and are thought to bind to target proteins and prevent their irreversible denaturing. There is evidence showing that hsp(72) production is induced by transient exposure to increased temperatures in a wide variety of organisms including molluscs. There is also evidence that hsp(72) is synthesized in response to other environmental stressors like heavy metal contamination or bacterial infection. The 70 kD heat shock proteins are highly conserved across the phylogenetic spectrum. We are testing the hypothesis that induced hsp(72) is produced in gills of the ribbed mussel Geukensia demissa as part of an adaptive response to increased salinity. Western blots indicate that this species is able to produce both the constitutive and induced forms of hsp70. Data will be presented to show whether changes in salinity induce production of hsp(72). Supported by a CSU-AAUP grant to MAK.