MP7 Toxicogenomics in Environmental Studies
Monday, 14 November 2005: 8:00 AM - 5:30 PM in Exhibit Hall

(VAR-1117-827374) The Effect of Concentration on Gene Expression Profiling in Daphnia magna.

Varshavsky, J¹, Poynton, H¹, Chang, B¹, Holman, P¹, Loguinov, A¹, Bauer, D², Colbourne, J², Vulpe, C¹, ¹ UC Berkeley, Berkeley, CA, USA² Indiana University, Bloomington, IN, USA

ABSTRACT- Despite the threat that pollution poses to aquatic ecosystems, the present methods for identifying the chemicals responsible for toxicity in the environment are not specific or simplistic enough for routine monitoring. The emerging field of ecotoxicogenomics involves using gene expression profiling to both sensitively indicate stress to an ecosystem and identify the casual agents. We have shown that the metals copper, cadmium, and zinc cause the differential expression of unique subsets of genes and have identified gene expression profiles for these metals at the 1/10 LC50. However, different concentrations of metals present in the environment will influence the gene expression profiles for these metals. We have performed microarray hybridizations using high (acute No Observable Effect Concentration [NOEC]) and low (chronic 1/10 EC50) concentrations for copper, cadmium, and zinc. We will compare the similarities and differences in gene expression at the different concentrations. In addition, we will address the sensitivity of gene expression profiling and determine whether a microarray-based assay can detect the presence of metals at levels below those that cause chronic phenotypic responses.

Key words: cDNA microarray, gene expression profiling, metals, daphnia magna