Project description:The Atlantic killifish (Fundulus heteroclitus) is an ideal model species to study physiological and toxicological adaptations to stressors. Killifish inhabiting the PCB-contaminated Superfund site in New Bedford Harbor, MA (NBH) have evolved resistance to toxicity and activation of the aryl hydrocarbon receptor (AHR) signaling pathway after exposure to PCBs and other AHR agonists. Until recently, a lack of genomic information has limited efforts to understand the molecular mechanisms underlying environmental adaptation to stressors. The advent of high throughput sequencing has facilitated an unbiased assessment of coding as well as non-coding RNAs in any species of interest. Among non-coding RNAs, microRNAs (miRNAs) are important regulators of gene expression and play crucial roles in development and physiology. The objective of this study is to catalog the miRNAs in killifish and determine their expression patterns in the embryos from contaminated (NBH) and pristine (Scorton Creek, MA (SC)) sites. Embryos from NBH and SC were collected daily from 1 to 15 days post-fertilization and RNA from pooled samples from each site was sequenced using SOLiD sequencing. We obtained 7.5 and 11 million raw reads from pooled SC and NBH samples, respectively. Analysis of the sequencing data identified 216 conserved mature miRNA sequences that are expressed during development. Using the draft killifish genome, we retrieved the miRNA precursor sequences. Based on the capacity of these putative precursor sequences to form the characteristic hairpin loop (assessed using RNAfold), we identified 197 conserved miRNA sequences in the genome.
Project description:The Atlantic killifish (Fundulus heteroclitus), native to estuarine areas of the Atlantic coast of the United States, has become a valuable ecotoxicological model due to its ability to acclimate to rapid environmental changes and adapt to polluted habitats. Killifish respond to rapid increases in salinity with an immediate change in gene expression, as well as long-term remodeling of the gills. Arsenic, a major environmental toxicant, was previously shown to inhibit the ability of killifish gill to respond to a rapid increase in salinity. We characterized miRNA expression in killifish gill under salinity acclimation with and without arsenic and identified a small group of highly expressed, well-conserved miRNAs as well as 16 novel miRNAs not yet identified in other organisms.
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:Subspecies of the Atlantic killifish, Fundulus heteroclitus, differ in their maximum thermal tolerance. To determine whether there is a link between the heat shock response (HSR) and maximum thermal tolerance, we exposed 20ºC acclimated killifish from these subspecies to a 2hr heat shock at 34ºC and examined gene expression during heat shock and recovery using real time quantitative PCR and a heterologous cDNA microarray designed for salmonid fishes. Keywords: Expression profiling by array
Project description:Subspecies of the Atlantic killifish, Fundulus heteroclitus, differ in their maximum thermal tolerance. To determine whether there is a link between the heat shock response (HSR) and maximum thermal tolerance, we exposed 20ºC acclimated killifish from these subspecies to a 2hr heat shock at 34ºC and examined gene expression during heat shock and recovery using real time quantitative PCR and a heterologous cDNA microarray designed for salmonid fishes. Keywords: Expression profiling by array Microarray analyses were performed on four individual fish per subspecies of killifish (northern and southern) prior to heat shock (control) and after 60 minutes of heat shock, hybridized (one slide per individual) against a common reference RNA pool composed of an equal amount of RNA from all samples in the analysis.
Project description:Traits that are relevant for resilience to climate change are polygenic and not correlated in Atlantic killifish, Fundulus heteroclitus