RESEARCH INTERESTS

1. Wildlife as indicators for endocrine disruptors

A growing number of substances released into the environment have been identified as disruptors of critical, normal hormone-dependent mechanisms in humans and animals. These endocrine disruptors come from a variety of sources such as plants, pharmaceuticals, pesticides, environmental pollutants, and industry. The impact of these diverse compounds is far-reaching; from effects on human and wildlife health to contributing to wildlife population declines and resultant ecosystem imbalances. Particularly vulnerable are those life stages where considerable modeling or remodeling of existing body plans occur such as in embryonic development, metamorphosis, infancy, childhood and lactation. Thus, exposure to endocrine disruptors at any of these critical stages could result in permanent dysfunction, increased susceptibility to certain cancers and reproductive problems reaching as far as multiple generations. It is critical to have the appropriate tools in place to identify the existence of endocrine disruptors in water samples (where most will eventually end up) and to properly evaluate any endocrine disruptor risk in chemicals that are to be released into our environment. Amphibians, fish, marine mammals, bivalves, and other wildlife species are our sentinels. By developing and using a wide range of molecular approaches that include multi-species DNA arrays, quantitative real time PCR, metabolomics and proteomic techniques, we are uncovering the mechanisms of action of potential endocrine disruptors and are gaining insight into how hormones function in different tissues and species.

2. Cellular mechanisms of amphibian metamorphosis

Critical to the normal development and maintenance of an organism’s health is ensuring that an appropriate balance is struck between two disparate processes: cell proliferation and programmed cell death. Although a great deal is understood about the machinery involved in both processes, the factors that are critical in determining which pathway cells take is not known, particularly when a single stimulus can simultaneously elicit both outcomes. A classic example of this is the normal postembryonic development of the frog. A marked elevation of thyroid hormone (TH) levels triggers the rapid and dramatic metamorphosis of the aquatic tadpole to a terrestrial juvenile frog. The most obvious changes observed are the disappearance of the tail and the growth of the legs. This program focuses on understanding how the tail “knows” that it should die after receiving the triggering message from TH. We are particularly interested in the role that cell cycle regulating proteins and phosphorylation may be involved in determining cellular outcome. Since frogs are vertebrates, the knowledge obtained by studying them can be easily applied to humans and, hence, will give us important clues in the control of cell death and cancer.

Last Update, Feb 2013