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Gene Expression and Genetic Damage Indicators in Fish Exposed to Varying Stream Conditions in a Midwestern Watershed
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| Abstract: | Newly developed molecular diagnostic exposure indicators were evaluated as part of a riparian zone assessment for environmental stressors. Water and fish samples collected from 12 headwater tributaries in the Little Miami River Basin were evaluated for the presence of estrogenic compounds and polycyclic aromatic hydrocarbons, measured by vitellogenin (Vg) and cytochrome P4501A1 (P450) gene expression, respectively; and genotoxicants, measured by single cell gel electrophoresis (SCG) and micronucleus (MN) assays. Larval fathead minnows (Pimephales promelas) were exposed to stream water and a laboratory control water for 24 hours. Total RNA was isolated and Vg and P450 gene expression were measured using designed synthetic oligonucleotide primers in quantitative RT-PCR. Fish blood samples obtained from bluegill sunfish (Lepomis macrochirus) and white suckers (Catostomus commersoni) were used for the SCG and MN analyses. For the SCG assay, the tail moment parameter was analyzed by computerized image analysis. Micronucleus frequencies were analyzed in polychromatic erythrocytes (PCE) and normochromatic erythrocytes (NCE), and the PCE:NCE ratio determined. Results indicated an increase in P450 gene expressio in fathead minnow larvae exposed to water samples from all 12 streams as compared to control laboratory water, the highest being observed in Turtle Creek. A marginal increase in Vg gene expression was observed only in three streams. Neither the SCG or MN parameters from fish blood cells showed evidence of significant exposure to genotoxic contaminants in any of the streams. Relational databases for a range of field-measured stream condition paramerters--land cover metrics, nutrient levels, and in-stream habitat measures--will be discussed. |
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| Citation: | Chang, L. W., J. R. Meier, F. B. Daniel, J. M. Lazorchak, D. L. Lattier, and G. P. Toth. Gene Expression and Genetic Damage Indicators in Fish Exposed to Varying Stream Conditions in a Midwestern Watershed. Presented at Society of Environmental Toxicology and Chemistry, Baltimore, MD, November 11-15, 2001. |
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| Contact: |
Linda Ransick - (513) 569-7395 or ransick.linda@epa.gov
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| Division: |
Ecological Exposure Research Division |
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| Branch: |
Molecular Ecology Research Branch |
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| Product Type: |
Abstrct/Oral |
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| Presented: |
11/11/2001 |
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