Fundulus heteroclitus exposed to Cr(III)

Cr(III) is the dominant toxicant at some Superfund sites within the United States and therefore we are interested in its effects. Cr(III)’s mechanisms are not well studied or understood because of its low bioavailability. We have attempted to characterize the effects of Cr(III) on gene expression in the liver of adult male Fundulus heteroclitus. The NOEC and LOEC were determined at 32 and 64mg/L, respectively, by measuring growth after exposing juveniles for 30 days. Secondary exposures were performed with adult males at 32mg/L, livers excised, and RNA extracted. Microarrays were probed with cDNA from untreated or Cr(III)-exposed adult fish and gene expression was quantified. Cr(III) at 32mg/L altered the expression of 5 genes, including GSTalpha, GSTtheta, and ALDH4. Ultimately, we anticipate using this gene expression information to determine whether chromium is available at potentially adverse concentrations in contaminated sites. Keywords: dose response Four fish were untreated. Four fish were exposed to 32mg/L (0.62mM) Cr(III) for 7 days with media renewals every 48 hours. Mummichogs were housed at 25C in a 14/10 light/dark cycle at 18‰ salinity. Adult mummichogs were exposed to Cr(III) at 0 or 32mg/L (0.62mM) (NOEC) individually in 4 L tanks for 7 days. At the conclusion of the exposures, livers were excised and placed in TRI-Reagent® for RNA isolation (Sigma Chemical Co, St. Louis, MO), and stored at -80C.