Project description:Cr(VI) is a common bioavailable toxic metal that can cause oxidative stress, DNA adducts, and perturb normal gene expression. Changes in gene expression are useful biomarkers of toxicant exposure that provide information about the health of an organism, its ability to adapt to its environment, and indicate potential toxicant-specific effects. Therefore, we developed a toxicology array to the estuarine sentinel species Fundulus heteroclitus, or mummichog. Juvenile mummichog were exposed to potassium dichromate for thirty days at concentrations from 0 to 24 mg/L of Cr(VI), and growth was measured to determine the NOEC (1.5 mg/L or 0.0288 mM) and LOEC (3 mg/L or 0.0577 mM). Body burdens from Cr(VI) exposed fish demonstrated a dose dependent increase and were inversely correlated to body weight. Cr(VI)-exposed juvenile mummichog differentially expressed greater than 20 genes in a dose-dependent manner, including hepatic glucose transporter 2, liver fatty acid binding protein, ATPase synthase 8, type II keratin, TBT binding protein, and complement component C3-2. Many of these genes are involved in energy metabolism or growth, which is consistent with the reduced growth caused by Cr(VI). Keywords: dose response
Project description:Cr(VI) is a common bioavailable toxic metal that can cause oxidative stress, DNA adducts, and perturb normal gene expression. Changes in gene expression are useful biomarkers of toxicant exposure that provide information about the health of an organism, its ability to adapt to its environment, and indicate potential toxicant-specific effects. Therefore, we developed a toxicology array to the estuarine sentinel species Fundulus heteroclitus, or mummichog. Adults males were exposed to Cr(VI) for 7-days at 0, 1.5 (NOEC), or 3 mg/L (LOEC). Livers were excised and RNA isolated. Adults are used in the laboratory experiments so that we can compare laboratory studies to fish caught at chromium-contaminated field sites. Cr(VI) altered the expression of 12 genes in adult liver, including hepatic growth factor activator, heart fatty acid binding protein, and complement component C3-2. Keywords: dose response
Project description: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
Project description:This SuperSeries is composed of the following subset Series: GSE12858: Technical Analysis of Fundulus heteroclitus cDNA Microarrays, experiment A GSE12898: Technical Analysis of Fundulus heteroclitus cDNA Microarrays, experiment B Refer to individual Series