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Localization of the Stress Response Among Tissues and Subcellular Compartments as a Potential Reflection of Site-Specific Toxic DamageEPA Grant Number: GF9500231
Title: Localization of the Stress Response Among Tissues and Subcellular Compartments as a Potential Reflection of Site-Specific Toxic Damage
Investigators: Ellison, Homer
Institution: California State University - Los Angeles
EPA Project Officer: Broadway, Virginia
Project Period: May 15, 1995 through January 1, 2000
Project Amount: $23,796
RFA: STAR Graduate Fellowships (1995) Recipients Lists
Research Category: Academic Fellowships , Ecological Indicators/Assessment/Restoration , Fellowship - Ecology
This project will test the hypothesis that the stress proteins, stress-70 and cpn60 accumulate at sites of toxic damage under environmental conditions and therefore can be used to identify the tissues and subcellular compartments targeted by an environmental contaminant, thereby providing valuable information on the sites of toxic action of the compound. The project will examine the stress response in the bay mussel, Mytilus edulis, exposed to a common class of xenobiotics, polycyclic aromatic hydrocarbons (PAH's), under both laboratory and field conditions and compare that to the specific tissues and subcellular compartments damaged by the PAH's.
The approach will be to incubate juvenile M. edulis in the laboratory over a range of PAH concentrations, using appropriate controls, in order to characterize the stress response elicited to this class of xenobiotics in target and nontarget tissues. Accumulation of stress proteins will be compared to the sites of damage, determined by histopathological examination. Immunoassay using antibodies that bind specifically to protein adducts will be used to locate intracellular sites of proteotoxicity.
Quantitative Western blotting will be used to determine the stress-70 and cpn60 concentrations in the gill mantle and digestive gland. Visualization of the spatial pattern of accumulation of stress-70 and cpn60 within each tissue will be accomplished by cross-sectioning of the frozen tissues and immunohistochemistry techniques. The subcellular localization of the stress response will be determined using immunocytochemistry. In order to correlate tissue and subcellular effects with organismal effects, growth rates of all M. edulis used in the study will be determined in terms of wet weight and shell length. To determine if a similar response is induced in situ juvenile M. edulis will be deployed at a study site in the San Diego Bay for thirty days at a gradient of known concentrations similar to those used in laboratory incubations. A subset of these mussels will be brought back to the laboratory immediately for analysis for comparison to the deployed samples. The characterization of the in situ response, in terms of stress protein induction and toxic effects, will be compared to the laboratory results to demonstrate applicability to realistic environmental systems.