USGS Washington Water Science Center
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Evaluation of Juvenile Trout Microarray Tools in the Development of an Ambient Monitoring Approach for Urban Streams
In spring 2010, the USGS will demonstrate the use of cDNA microarray techniques performed on larval trout both in the field and a laboratory setting as a method for assessing the suitability of streams for supporting salmon early lifestages. Gene microarray analysis measures the expression of hundreds or thousands of genes from an organism exposed to chemical pollutants. Microarrays for assessing environmental contaminants evolved from microarrays used to study developmental processes or basic physiology. Microarrays note when genes are turned on and when they are turned off. A gene might turn on to resist toxicity or turn off because of interference from a chemical. Scientists have discovered patterns of microarray response that are diagnostic of some chemicals. The manufacture and reading of microarrays have been automated. Some tissue preparation is needed prior to microarray exposure.
In the spring/early summer of 2010, Washinton State Department of Ecology will provide the USGS with a minimum of 40 larval rainbow trout that have been exposed to natural stream flow found in Indian Creek in the Olympia area. The fish will be equally distributed from two sites (upstream and downstream) with varying levels of suspected contamination on Indian Creek. The USGS will assess transcriptional responses on whole larval fish using a custom made low density targeted rainbow trout cDNA microarray. The USGS will provide microarray results from the upstream site and from the downstream site. A laboratory study will also be performed using larval rainbow trout. In the laboratory study, Ecology will expose a minimum of 170 larval rainbow trout to contaminated waters of know source and condition. At the end of the exposure period, Ecology will extract the livers out of a minimum of 150 fish. The livers will be preserved on dry ice or other preservative provide by the USGS in three evenly disturbed groups. Each group of 50 livers needs to equal 50mg. Ecology will provide the USGS with the remaining fish from this laboratory study as well. The USGS will perform microarray analyses on the liver samples and 3 analysis on the whole fish. During the laboratory study, Ecology will also expose a minimum of 20 larval rainbow trout to clean water. The USGS will perform 3 microarray analyses on the 20 fish exposed to the clean laboratory water. Ecology will also provide the USGS with ancillary chemistry data from the Indian Creek sites and laboratory exposures to be used in the USGS's report. A brief USGS report will be published online.