You are here: Home › Stressors › Hypoxia & Nutrient Pollution › Current Programs › Aquatic Research Consortium Year 1: An Environmental Toxicogenomic Approach to Small Aquarium Fish Models
Aquatic Research Consortium Year 1
An Environmental Toxicogenomic Approach to Small Aquarium Fish Models
Issue
Toxicogenomics combines the emerging technologies of genomics and bioinformatics to identify and characterize the actions of toxins in ecosystems. New opportunities for studying toxicological and ecosystem processes enable molecular biologists to examine genetic changes in expression. This is done simultaneously, using miniaturized chemical reaction areas to test DNA fragments, antibodies, or proteins (microarray technology). The toxicogenomic approach allows investigators of diverse research disciplines to potentially discover structural DNA and RNA (bases) molecule sequences at a unique physical location in the genome. Ultimately, this shows genetic expression based on particular environmental conditions, and allows us to better understand heritable factors of complex traits such as behavior, disease resistance, and other attributes using experimental animal models.
Approach
The toxicogenomics approach uses RNA extracted from model fish species and exposed to hazardous chemicals, such as PAHs, haloacetic acids, endocrine-disrupting chemicals, peroxisome proliferators and heavy metals. The results are assessed for modulated patterns in gene expression using the microarrays in development. The ease with which these fish models can be experimentally manipulated allows dose response effect measurement. Another objective of the project is to determine whether differences in sensitivity of these distinct model species to toxic chemicals can be understood at the molecular level from differences in the gene expression patterns. Such data may be relevant to understanding heterogeneity among feral fish populations to adverse effects from environmental exposure. These goals will be pursued by:construction and testing of medaka and Xiphophorus microarrays responsive to environmental insult; analysis of gene expression patterns in model fish species exposed to hazardous chemical; and dose response relationships for biological versus molecular endpoints. The overall objective of this project is to construct microarrays for two aquaria fish model systems, Japanese medaka (Oryzias latipes) and platyfish/swordtails (Xiphophorus) These models will assess the effects of water-borne biological and chemical contaminants on damage and diseases in fish populations. Each of these two aquaria fish models has valuable, unique attributes as toxicological comparison models with other fish species responses, and act as surrogates for higher animal models. Data from the application of microarray technologies to these aquaria models are valuable for assessing feral fish health, and to indicate molecular effect from environmental toxin exposure. The proposed studies represent first steps toward using fish to create a portrait of risk to animal populations from exposure to hazardous environmental contaminants.
Management/Policy Implications
The proposed studies will enhance scientific knowledge regarding molecular toxicity mechanisms and the cellular defense and recovery process in vertebrates. Furthermore, these advances will apply within the scientific community to better understand heterogeneity among existing fish populations in estuarine and oceanic systems. The process may also be used to model exposures and susceptibility to genetic damage and diseases that have an environmental cause. This information will assist Federal agencies in fish stock health assessment and the effects of human-induced environmental toxicant inputs, as well as add fundamental knowledge on the overall genomic effects of environmental toxicants.
Accomplishments
New Program. The Aquatic Research Consortium is a collaboration of scientists from the Gulf Coast Research Laboratory of The University of Southern Mississippi and from Southwest Texas State University. The studies’ overall aim is to delineate specific genetic changes reflecting exposures to adverse environmental conditions. The proposed program will build on collective expertise in molecular genetics and toxicology, aquatic animal stock maintenance, refined exposure methodologies and toxicological response assessments. Ultimately, the data acquired and the models developed will be used to assess and monitor responses of both laboratory and feral fishes to environmental perturbations.