Successful Summer of Research Draws to a Close

Thirteen AU students – an all-time high for our programs – have participated in research with AU science faculty this summer on a variety of projects. Pictured above are (standing, left to right): Megan Liggett, Phillip Wages, Zachary Il'Giovine, Jacqueline Skiba, Charles Davis, Rachel Day, and Torrie Goudy; and (kneeling, left to right): Tricia Matz, Nicole Genco, Amy Drossman, Heather Bensinger, and Wendy Dria. Not pictured: Jennifer Miller. Funding for this research has come from a variety of sources including grants from the Merck Foundation, National Science Foundation, National Institutes of Health, and the Dr. Scholl Foundation.

Using zebrafish to study the effects of urban pesticides

Ashland University has one of only a handful of undergraduate Toxicology degree programs in the United States. One of our current Toxicology majors, Phillip Wages, is working on his honors thesis in collaboration with two professors: Dr. Andy Trimble, a toxicologist specializing in the effects of urban pesticides, and Dr. Mason Posner, a physiologist who studies the evolution and function of the vertebrate eye.

Phillip Wages in our zebrafish aquarium facility

Pesticide use is a common way to eliminate pests for optimal crop growth; however, their misuse or over use can be harmful to non-target organisms and possibly even consumers. Toxicity testing of pesticides is not a new thing, but the incorporation of pesticide mixtures and the use of a versatile model organism will hopefully form a more complete description of the effect pesticides have on the environment. Both atrazine and permethrin are commonly used on crops together to eliminate unwanted weeds and insects respectively, but after it rains both of these commonly end up in streams and lakes and could potentially disrupt these ecosystems. For this reason, zebrafish become ideal model organisms because they can be used to understand the basic toxicity of these pesticides and hormonal and protein disruption with relative ease. This approach to understanding the effects of pesticide could ultimately change the outlook of how pesticides are administered and regulated.

-Phillip Wages

Evaluating the threat from cadmium in jewelry

Jennifer Miller is next in our series of profiles on summer undergraduate research students. She is working with Dr. Jeff Weidenhamer on a project funded by a grant from the Dr. Scholl Foundation.

Young girls love to wear jewelry. Bejeweled hearts, butterflies, angels, peace signs, ladybugs and ballerinas may look appealing, but if made of the toxic metal cadmium, they can be deadly. We used a method called X-Ray Fluorescence Spectroscopy to screen these jewelry items for cadmium levels; items with unusually high concentrations are marked for further analysis. Since the vast majority of these jewelry pieces appeal to children, further testing is preformed to model feasible contact a child may have with the cadmium-based charms. These tests simulate the exposure that a child might get by mouthing or swallowing a charm, along with a total cadmium analysis of each piece. Exposure to cadmium is cause for concern because cadmium bio-accumulates, meaning that the body cannot cleanse itself of this toxin. Over time cadmium builds up and can cause adverse health effects including kidney failure, cancer and osteoporosis. Exposure to high cadmium jewelry items adds to the total cadmium accumulated in day to day life, mainly from eating food as cadmium is present in the soil and is taken up by plants. Our research has contributed to three recalls of jewelry items for cadmium contamination by the Consumer Products Safety Commission, which is currently working on a proposal for the regulation of cadmium in children’s jewelry.

- Jennifer Miller

Finnish Scientist Visits AU to Conduct Ecological Research

Dr. Jeff Weidenhamer is hosting a visiting scientist this summer from the University of Helsinki, Prof. Aki Sinkkonen. They are conducting collaborative experiments on how the growth responses of plants to environmental toxins are modified by plant density, as well as exploring new approaches to data analysis from plant growth experiments. During his Ph.D. research, Dr. Weidenhamer discovered that because plants compete for toxins the way they do for nutrients, plants growing at low densities suffer greater growth reductions because they receive a larger dose of the toxins. This phenomenon has relevance to studies of phytoremediation – the use of plants to detoxify soils contaminated with high concentrations of heavy metals such as lead or cadmium, or organic toxins such as creosote. Prof. Sinkkonen has extended this concept to develop mathematical models of plant growth in the presence of toxins, and has applied these models to the analysis of experimental data from plant growth studies. The results of the experiments that Prof. Sinkkonen is conducting with Dr. Weidenhamer may help in the development of bioassays to determine pollutant impacts.

Neurobiology and biochemistry collaboration studies brain function

Next in our series of profiles on summer undergraduate research students is Charles Davis, who is working with Drs. Steven Fenster and Becky Corbin as part of our Merck/AAAS Foundation summer research program.

The central nervous system (CNS), which includes the brain and spinal cord, functions like a network receiving and relaying messages back and forth from different parts of the body. Cells called neurons form the functional architecture of the CNS and regulate neuronal communication in the nervous system. My research focuses on the analysis and function of the protein Neuronal Interleukin-16 (NIL-16). NIL-16 is a protein expressed exclusively in neurons of the CNS. Two specific areas of the brain in which NIL-16 protein is highly expressed are the hippocampus and cerebellum, which are associated with learning and memory, but are also vulnerable to neurodegenerative diseases such as Alzheimer's disease. NIL-16 is a multi-domain scaffolding protein capable of organizing signaling complexes in neurons. These neuronal signaling complexes are critical for efficient communication between neurons. Understanding how signaling complexes form in neurons is significant to our understanding of how the brain works. The long-term goal of this research is to identify proteins that interact with the NIL-16 protein. In order to identify the unknown proteins we used MALDI (TOF) analysis, which is a state of the art biochemical technique. MALDI (TOF) analysis uses a laser beam to cause ionization of the protein sample, which produces a mass spectrum. This mass spectrum allows for the unknown protein to be compared to a standard and accurately identified. Identifying unknown protein complexes that interact with NIL-16 will contribute toward understanding how the brain works and will also provide improved diagnosis and treatment of nervous disorders.

- Charles Davis

How can fungi help to understand human sleep disorders?

Biology major Wendy Dria has been performing independent research with AU Microbiologist Dr. Andrew Greene for the past year and is continuing her work this summer into the internal clock mechanism that maintains biological rhythms.

"The project that I am working on is the identification of circadian clock-associated proteins in the fungi Aspergillus nidulans and Aspergillus flavus.  Circadian rhythms are ~24 hr long cycles of behavioral processes that occur throughout the day that can be monitored or set using light/dark or temperature cycles. We are using the fungus Aspergillus as our model organism because its circadian rhythm cycles can easily be monitored.  Fungal circadian rhythm research can be applied to human sleep disorders because the properties of the clock are similar. I have identified many proteins involved in the circadian rhythm clock and I am currently trying to confirm their identity and cycling using real-time PCR."

- Wendy Dria