Meghan Doyle

MSc candidate (September 2010 - present)

Hometown: Sussex, NB
Education: BSc (Hon) Marine Biology, 2010, University of New Brunswick
Contact: meghan.doyle@unb.ca; 648-5985

Research: "The effects of ethinylestradiol (EE2) on molecular signalling cascades in mummichog (Fundulus heteroclitus)"

My current research focuses on the effects of ethinylestradiol (EE2, one of the main components of the birth control pill) on molecular signaling cascades in mummichog (Fundulus heteroclitus). EE2 has become a model compound for studying estrogen receptor-mediated pathways because of its environmental relevance as well as its known effects on reproductive endpoints in fish at low concentrations.

At environmentally relevant concentrations, EE2 has had a variety of documented effects at the population, organism, tissue, and physiological levels. While other species like fathead minnow, zebrafish and Japanese medaka reduce or undergo complete shutdown of egg production at or below 100 ng/L, the mummichog is unique in that it will continue to produce and fertilize eggs normally despite exposures to very high concentrations of EE2 (up to 3,000 ng/L).

The objective of this thesis is to identify molecular signalling cascades of EE2 exposure in mummichog and to determine whether these signals are unique to mummichog compared to other teleost fishes that have been exposed to EE2.  I will investigate effects of EE2 on genes involved in lipid mobilization and transport as well as steriodogenesis, which are two important (E2 regulated) pathways involved in egg production.

In addition, I will use a mummichog microarray to identify genomic responses that will provide novel insight into how mummichog are able to produce eggs normally with high levels of xenoestrogens.

The mummichog is a widely used and well recognized model to study the toxicity of environmental contamination. Although mummichog show no effect at this higher level endpoints, changes at the molecular level may be occurring, which could then be used as sensitive molecular biomarkers in other species.

This study will greatly enhance our understanding on the mechanistic basis for effects of EE2 and species differences in sensitivity to xenoestrogens. It will also provide information for bioassay protocols in this species and development of effective procedures for assessing exposure to EE2 and effects on fish.

Recent scientific publications

Bosker, T., Hewitt, M., Doyle, M., MacLatchy, D. 2010. Effects of neutral sulfite semi-chemical pulp mill effluent in the mummichog (Fundulus heteroclitus) adult fish reproductive test. Water Quality Journal of Canada 45(2): 201-208.

Doyle, M., Bosker, T., Munkittrick, K.R. 2011. The potential use of Atlantic silverside (Menidia menidia) for monitoring estuarine pollution. Journal of Environmental Monitoring DOI:10.1039/C1EM10629E.