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Grantee Research Project Results

Grantee Research Project Results

Developing the Mosquitofish as a Robust Bioindicator Organism for Endocrine Disrupting Compounds by Elucidating the Molecular Mechanisms That Regulate Responses to Androgens

EPA Grant Number: FP917281
Title: Developing the Mosquitofish as a Robust Bioindicator Organism for Endocrine Disrupting Compounds by Elucidating the Molecular Mechanisms That Regulate Responses to Androgens
Investigators: Anderson, Erica K
Institution: University of Florida
EPA Project Officer: Cobbs-Green, Gladys M.
Project Period: September 1, 2011 through August 31, 2014
Project Amount: $126,000
RFA: STAR Graduate Fellowships (2011)
Research Category: Fellowship - Pesticides and Toxic Substances , Academic Fellowships

Description:

Objective:

Endocrine disrupting chemicals interfere with hormonal balance and can impact reproduction and development. Several species of aquatic animals that live downstream of paper mills have abnormal characteristics that indicate exposure to endocrine disruptors. In the State of Florida, one species of freshwater fish—the mosquitofish—has been observed with abnormal secondary sexual characteristics at three paper mill-impacted sites. This research project will delve into the mechanisms of how the female mosquitofish that live downstream of paper mills exhibit male-specific physical characteristics. Results will enable the mosquitofish to be further developed into an organism that can be sampled from polluted environments to determine the environmental impacts of paper mill effluents and other endocrine disruptors.

Approach:

A combination of laboratory experiments and field work will be used to determine the role of gene expression in the development of the malespecific secondary sexual characteristic: the anal fin. In the laboratory, female mosquitofish will be exposed to endocrine disruptors (androgens) that are known to cause anal fin growth. Changes in the expression of genes known to regulate anal fin growth in other species will be monitored to determine the role of these pathways in mosquitofish anal fin growth. Further analysis of how these genes regulate one another will be determined in experiments with mosquitofish fry exposed to androgens and chemicals that can inhibit these genes. Hepatic gene expression analysis will be conducted on the androgen-exposed female mosquitofish using a microarray, a powerful technology that enables the quantification of thousands of genes at once. This microarray data will be compared to microarray data from the masculinized female mosquitofish that live downstream of the paper mill to determine if these fish are being exposed to a chemical that acts like an androgen. A biomarker of reproductive health also will be measured in field samples to determine if the abnormal female mosquitofish also may be impaired in their ability to reproduce.

Expected Results:

Understanding the mechanisms that are responsible for abnormal anal fin growth in mosquitofish will allow for more accurate interpretation during field studies of endocrine disrupting chemicals using this species. This research also will provide information of the mechanisms by which paper mill effluents in the State of Florida are acting as endocrine disruptors and if this exposure is linked to potential reproductive effects. The long-term goal of this project is to develop the mosquitofish into a bioindicator: an organism that can be sampled from polluted environments to determine the environmental impacts and potential risks of chemical exposure for both wildlife and human populations.

Potential to Further Environmental/ Human Health Protection

Masculinized female mosquitofish still are found in Florida’s freshwater systems that are impacted by paper mill effluents, and the risks of paper mill effluent exposure for other aquatic animals are greatly unknown. Determining the biological mechanisms that cause abnormalities in mosquitofish can help in understanding these effects and what risks may be conferred by other species in the area. This project can set the foundation for future studies using the mosquitofish as a bioindicator to evaluate the health status of paper-mill impacted sites and other ecosystems that are impacted by endocrine disruptors.

Supplemental Keywords:

endocrine disruption, paper mill effluent, aquatic toxicology, bioindicator

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The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.

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