Tag: Poster 63

Influences on U.S. Mammal Diversity over the 20th Century: Implications for Future Response to Climate Change

Presenter: Kendra Walters

Mentor: Edward Davis, Geology

Poster: 63

Majors: Geology and Biology

Biodiversity loss is recognized as a global crisis. Current research strives to quantify and predict the change in biodiversity throughout the world, focusing on a wide range of taxa. However, current predictive models of mammal diversity in the United States suffer from low precision. They are not scaled with adequate spatial or temporal resolution because richness has not been evaluated at a broad spatiotemporal scale. Our research is a high- resolution analysis of the changes in mammal diversity in the continental United States through the last 110 years.

We collected mammal occurrence data from the online database VertNet and individual museum collections, divided it into ten year increments, and used scripts in ArcGIS 10.2 to produce sampling-standardized patterns of mammal diversity in each decade. We then analyzed the geographic distribution of diversity change over the 20th century. Mammal diversity in the last century increased in two regions: one northern horizontal strip between 43° and 47° latitude and one southeast strip from Texas to North Carolina. Diversity decreased throughout the rest of the United States. Our study describes regions in the United States that are experiencing the most severe biodiversity changes which suggests that those regions should be focal areas for conservation efforts. Further directions include testing hypotheses about the role of climate and human population change to influence these patterns of mammal diversity shifts.

Effects of a Cognitive Task on Motor Output in Young Adults

Presenter: David Gallacher

Faculty Mentor: Anita Christie

Presentation Type: Poster 63

Primary Research Area: Science

Major: Human Physiology, Psychology

Funding Source: UROP mini-grant, $1000

It is widely accepted that multitasking with a motor task while performing a cognitive task will decrease performance, but we do not understand the underlying physiology. The purpose of our study was to assess the effects of a cognitive task on motor cortex excitability and inhibition in young adults. Transcranial magnetic stimulation was used to evoke responses from the first dorsal interosseous muscle. Excitability was assessed through the amplitude of motor evoked potentials (MEPs) and inhibition was assessed through the duration of cortical silent periods (CSPs). These measures were obtained under three conditions: (1) no cognitive task; (2) during a simple cognitive task; (3) during a complex cognitive task. MEP amplitude was increased during both simple and complex cognitive tasks; however, this did not reach statistical significance (p=0.06). The duration of the CSP was unaffected by the cognitive tasks (p=0.74). These results suggest that a cognitive task may increase motor cortex excitability, but does not affect inhibition.

Calcium Imaging of Mice Brains Injected with Glutamate-Sensing Fluorescent Reporter (GluSnFr)

Presenter(s): Nelly Nouboussi − Biology, Human Physiology

Faculty Mentor(s): Matt Smear, Teresa Findley

Poster 63

Research Area: Natural science

One of the most important tasks a sensory system performs is locating the source of a stimulus. However, very little is known about how the olfactory systems localizes odors. The goal of this project is to develop a technique that will allow us to image the glomeruli, the area in the brain where neurons from the brain and the nose connect. We will image using superfolder intensity-based glutamate-sensing fluorescent reporter (referred to as GluSnFR), which localizes to the extracellular surface of neurons and can thus report concentrations of the neurotransmitter glutamate at synapses. A virus carrying the GluSnFr gene will be injected in the brain during survival surgeries. The first step in this project is to confirm that GluSnFr is expressed by the cells of interest, which will be accomplished by sectioning samples of mice brains 2 weeks after injection, and looking for expression using a microscope. Once it is established that GluSnFr is expressed, we will perform glutamate imaging to obtain images of olfactory bulb activity. We predict that GluSnFr will indicate when neurons are firing, and this will be illustrated in the images taken. This is significant because this technique will ultimately be used to image the glomeruli of mice performing olfactory search tasks, in order to establish a correlation between the activity of neurons and the behavior of the animals.

Investigating the relationship between heat-stress induced DNA damage and the synaptonemal complex in spermatogenesis

Presenter(s): Cailan Feingold

Faculty Mentor(s): Diana E Libuda & Cori C. Cahoon

Poster 63

Session: Sciences

Male fertility defects affect approximately one-third of couples who are unable to conceive, however many of the male-specific mechanisms that contribute to infertility are unknown. Spermatogenesis, unlike oogenesis and other developmental processes, is sensitive to temperature changes and requires a narrow isotherm of 2-7°C below core body temperature. Exposing spermatogenesis to elevated temperature conditions, both physiological and environmental, have been linked to increased risks of testicular cancer and male infertility. Despite these defects, the mechanisms behind heat-induced male infertility are unknown. In Caenorhabditis elegans, heat stress causes sperm-specific increases in DNA damage and destabilization of the chromosome structures essential for meiotic chromosome segregation. Notably, the largest increase in heat-stress induced DNA damage occurs during late prophase I, which coincides with the stage when the chromosome structures are prematurely lost. Therefore, the proteins involved in establishing these chromosome structures might play a direct role in preventing and/or limiting heat-induced DNA damage. However, the relationship between heat-induced DNA damage and chromosome structures has only been examined using static fixed images, which fail to demonstrate the progression of DNA damage and chromosome structure breakdown relative to one another. To understand the dynamic relationship between heat-induced DNA damage and chromosome structures, fluorescently tagged versions of a DNA damage protein (RAD-51) and a structural protein (SYP-3) will be made and live imaged in whole animals undergoing spermatogenesis both with and without heat stress. Overall, these experiments will determine whether chromosome structure instability directly impacts genome integrity during heat stress in developing spermatocytes.