My main interests are in how environmental information gets translated into developmental, behavioral, and reproductive responses and what role the endocrine system plays in the translation. I use amphibians as model systems.
Rex Bergamini - PhD Candidate
My principal research interests are in the areas of endocrine disruption, toxicology and pathogenicity as related to community-level effects in freshwater aquatic ecosystems. To that end, my current research is examining how local-scale changes in micropollutants (i.e., endocrine disrupting chemicals (EDCs)) affect the allelic frequency of genes responsive to variations in water quality. The aquatic vertebrate I use as a model organism is the ubiquitous and invasive Western mosquitofish (Gambusiaaffinis); however, my work may translate to understanding severe declines in several endemic aquatic species, including lowland leopard frogs (Rana yavapaiensis), several species of native fish, and the recently federally-listed semi-aquatic gartersnakes (narrow- headed gartersnake, Thamnophis rufipunctatus; northern Mexican gartersnake, Thamnophis eques megalops) endemic to Arizona, New Mexico and Mexico. For extracurricular fun, I work extensively with Dr. Erika Nowak of the Colorado Plateau Research station conducting research on gartersnakes and the Arizona black rattlesnake (Crotalus cerberus). I also consult on environmental contaminant-related issues and conduct habitat evaluations and clearance surveys for multiple federally-listed species, and as such I am currently one of two on-call biologists for the Yavapai-Apache Nation.
Molly Shuman-Goodier - PhD Candidate
I am interested in how widespread contaminants may indirectly affect species interactions and community composition in aquatic ecosystems. Currently, I am working in the Philippines to evaluate the effects of pesticide use on aquatic biodiversity in rice fields. Irrigated rice provides substitute wetland habitat for a number of invertebrate and vertebrate species that are directly exposed to pesticides after spraying, and we know very little about how chemical use may affect their physiology and alter key species interactions, such as competition. I also seek to identify management practices that promote biodiversity in rice, and to inform human health concerns related to field exposure through the use of amphibian models. My dissertation research is a product of an exciting collaboration between Dr. Singleton's laboratory at the International Rice Research Institute (IRRI), and Dr. Propper's laboratory at Northern Arizona University. I have recieved funding from the international project Closing Rice Yield Gaps in Asia (CORIGAP), NAU’s “Genes to Environment” IGERT training program, and the Achievement Rewards for College Scientists (ARCS) foundation. Most recently I am supported by a NSF/NAU GK-12 Teaching Fellowship. Check out my partner teacher's website for 7th grade science here.
Riley Smith - MS Student
The aim of my research is to examine the effects of the endocrine disrupting chemical (EDC), arsenic, on reproductive tissues and genes of western mosquitofish (Gambusia affinis) populations in northern Arizona. Specifically, I will evaluate the developmental outcomes of exposure to arsenic on G. affinis at three different levels: 1) the morphological level by identifying changes to metamorphic outcomes 2) the molecular level by detecting changes in gene expression 3) a population level by looking for signs of local adaptation to this contaminant. Investigating reproductive patterns and molecular markers, critical in development, will help us understand the mechanisms through which arsenic interferes with the health of human and wildlife communities. It is also important to look into solutions for existing health issues due to heavy metal exposure. As a part of this project, we are interested in learning about medicinal plants used by local Native communities that may mitigate health inflictions commonly caused by arsenic exposure. To fully understand the issues and to work toward solutions it is important to incorporate the traditional ecological knowledge (or localized knowledge from generations of experience) of local Indigenous peoples. Overall, I would like to develop an understanding of the ways natural resources and organisms are changing due to anthropogenic activity, understand the cultural ties between Indigenous groups and their resources, and hopefully be able to find practices to help sustain both.
Tomoko Wilson - MS Student
I am a biology master’s student whose thesis research is on arsenic’s effects on estrogen sensitive gene expression. I use zebrafish as an animal model. This is work is funded by the Partnership for Native American Cancer Prevention, and it is part of a bigger project that is looking at arsenic’s effect on breast cancer. Our hypothesis is that chronic exposure to arsenic at environmentally relevant levels converts the phenotype of breast cancer cells into a harder to treat model. I have also done research on complex chemical mixtures and their effects on gonadal development in the American Bullfrog, as well as work on T4’s effects on thyroid sensitive gene expression.