Tag: Poster 3

Ischemia Induced ER Stress in Skeletal Muscle Cells during Total Knee Arthroplasty Upregulates Proteins Involved with the Unfolded Protein Response

Presenter: Ryan Boileau

Mentor: Hans Dreyer

AM Poster Presentation

Poster 3

Estimated to be performed 3.48 million times annually by 2030, Total Knee Arthroplasty (TKA) is the most common surgery to remediate chronic osteoarthritis in older adults. During surgery, blood flow is occluded to the operative leg resulting in anoxic conditions within the distal tissues. We have previously shown that proteins regulating cap-dependent translation initiation and elongation are downregulated and components of the catabolic and cell stress pathways are upregulated during ischemia and reperfusion. The purpose of this study was to further characterize the effects of anoxia in muscle cells on proteins controlling components of the ER stress pathway, i.e., the unfolded protein response (UPR). Muscle biopsies were obtained at baseline (before TKA surgery), maximal ischemia (before tourniquet release), and reperfusion. Preliminary results suggest an increase in cytoplasmic levels of downstream targets of the UPR (ATF4, CHOP, JNK, and Bcl-2). Further research will elucidate protein targets for preconditioning therapies that may ameliorate the UPR in an attempt to mitigate the substantial muscle atrophy following this increasingly common procedure performed in older adults.

Investigating the Effect of Heat Shock on Lifespan and Gene Expression in C. remanei

Presenter : Sarah Mete

Mentor : Patrick Philips

Major : Human Physiology

Poster 3

Low doses of various stressors have been shown to slow the process of aging and increase tolerance to future stress in numerous organ- isms, a phenomenon known as hormesis. Previous studies conducted using C. elegans have examined heat-induced hormetic effects on lifespan; however, the presented data is conflicting and inconclusive. Studying the hormetic response to sub-lethal heat shock in C. remanei can help us understand the underlying mechanism of hormesis and its effect on lifespan in a new model organism. We pre- dicted that exposing an outbred population of C. remanei to either a mild heat stress, an acute heat shock or a combination of the two would produce a hormetic response in lifespan, observing the most beneficial response in those exposed to both treatments. The worms were raised either at 20°C, or exposed to a mild heat stress of 30°C during larval development. A subset of worms from each group were then subjected to a 36.8°C heat shock for 1 hour. We measured lifespan for each group in adult, virgin females maintained at 20°C. Surprisingly, no significant differences in lifespan were observed across the various conditions. These results stimulated the idea of us- ing RNA-sequencing to evaluate changes in gene expression to explain why no response in lifespan was observed. The sequencing data illustrated significant changes in gene expression associated with both the mild and acute heat treatments, indicating a large enough change to compensate for the heat stress but not enough to affect lifespan.

The Effects of Browsing and Grazing on Body Mass

Presenter: Mathew Beattie

Mentor: Samantha Hopkins

Poster: 3

Major: Biology/Geology 

Diet of mammals affects the metabolic rate, intelligence, and many other physical and behavioral characteristics. Understanding how the diets of mammals affect the development, evolutionary history, and overall biomass of species can be instrumental in understanding the needs of endothermic mammals and the large energy costs that it takes to maintain their bodies. Most large mammalian herbivores fall into two main dietary categories: browsers (animals that feed on the leaves, twigs, and the fruits of trees and shrubs) and grazers (animals that eat grasses
and forbs). It takes more mass of grass or forb to sustain a mammal than it does leaves or twigs; therefore, grazers must eat more food than browsers and will therefore have more body mass as a result of their dietary preference. A species body form is directly related to the actions it needs to do to survive. Therefore, by analyzing the phylogenetic relationship between the diet of Artiodactyla or “hooved mammals” in the families Bovidae (cows, sheep, goats, and antelope) and Cervidae (deer, moose, and elk), and the average body mass of species in each category, we have found that there is a strong correlation between increased body mass and grazing. However, this effect is mediated by habitat; those taxa that graze also tend to inhabit more open habitats, where the increased predation pressure may also select for greater size. Therefore, we will be analyzing the effect of diet, body size, habitat, and eventually tooth morphology to understand the evolutionary history of Artiodactyla.

The Phylogenetic Utility of Exon Primed Intron Crossing DNA Sequences in the Tribe Cecropieae

Presenter: Liam Beckman

Mentors: George Weiblen and Erin Treiber, College of Biological Sciences, University of Minnesota

Poster: 3

Major: Biology

Mutualisms, interactions between species that are beneficial to both partners, are useful systems for investigating how interactions may affect the evolution and diversification of lineages. Interactions between ants and plant species of the genus Cecropia are a classic example of mutualism but the origin and evolution of the mutualism is poorly understood. We examined whether the inclusion of an exon-primed intron-crossing (EPIC) marker could improve our understanding of Cecropieae phylogeny. We performed a Bayesian phylogenetic analysis of 15 species from which EPIC sequences were obtained. By comparing clade support from analyses with and without EPIC, we concluded that the addition of a third gene region strongly supports the hypothesis that the Afrotropical and antless genus Musanga was derived from a Cecropia ancestor and is most closely related to the antless neotropical species C. sciadophylla. Future research will work to add increased resolution to the Cecropieae phylogeny in order to achieve a greater understanding of this dynamic biological interaction—pointing the way to predicting how environmental factors such as climate change may shape mutualistic relationships between multivariate forms of life.

#SaveTheEarth: A Comparison of Environmental Organization’s Twitter Content to Uncover Which Types of Tweets Engage Users

Presenter: Sarah Arnell

Faculty Mentor: Autumn Shafer

Presentation Type: Poster 3

Primary Research Area: Social Science

Major: Journalism, Public Relations

Large environmental organizations operating in the U.S., such as Sierra Club and the World Wildlife Fund (WWF), are widely considered to be influential in shaping political policies and public opinion in regards to climate change, greenhouse gasses, preserving ecosystems, energy, and water consumption. In addition to relying on private public donors for funding, environmental organizations often call members to action in support of local and national lobbying efforts and community-based volunteer activities. One key outreach channel used by such organizations is Twitter. Although many of these organizations send several tweets a day to hundreds of thousands of followers, an initial review of the Twitter accounts of the largest U.S. based environmental organizations revealed most have extremely low engagement among their followers (i.e., less than 1% of followers are engaging with their tweets). In this study, we will conduct a quantitative content analysis of the Twitter feeds of four major environmental organizations and analyze successes (i.e., WWF has 3.7 times as many followers as Sierra Club, yet recent WWF tweets were shared 8.8 times and liked 21.1 times more often) and opportunities to better engage with their publics. We will compare organizations and tweets based on content, such as message framing (e.g., gain and loss frames), and follower engagement. This research will provide insights as to what types of tweets are most effective in motivating engagement.

Effect of Reward Size on the Activity of Auditory Cortical Neurons

Presenter(s): Jardon Weems − Biology

Faculty Mentor(s): Santiago Jaramillo

Poster 3

Research Area: Neuroscience

Funding: Peter O’Day Fellowship in Biological Sciences

The neural pathways that allow an animal to select the actions it should take in response to a sound in order to get a reward are not well understood. Recent work in our lab indicates that neurons in the region of the striatum that receive inputs from the auditory cortex fire differently in response to a sound when the sound is paired with a large reward in contrast to a small reward. These data suggest that the auditory striatum may integrate information about sound and reward size in a way that could support sound-action association learning. The primary aim of this study was to determine if reward related modulation observed in the striatal neurons is already present in the inputs arriving from the auditory cortex. To investigate whether auditory cortex integrates information about reward size during decision-making, we examined the activity of auditory cortical neurons in six male wild type C57BL/6J mice. Via chronically implanted electrodes, the mice performed an auditory reward- change task in which the same sound and same action was paired with different amounts of reward. We found that 7.5% of sound responsive auditory cortical neurons were modulated by the amount of reward during the decision-making task. In addition, we found a number of neurons in the auditory cortex that responded to movement, 21.8% of which were modulated by reward size. Our previous research found that 13.9% of sound responsive neurons in the auditory striatum and 25.7% of movement responsive neurons in the auditory striatum were modulated by reward size. Together, our results suggest that auditory cortex contributes to the integration of information about reward size and auditory stimuli during decision-making, but to a lesser extent than the auditory striatum.

Strain In Butte, Montana

Presenter(s): Owen Smith − Geology

Faculty Mentor(s): Ray Weldon, Mark Reed

Poster 3

Research Area: Geology

From the uplift of the Rocky Mountains to the basin and range extension, Butte Montana has undergone dramatic tectonic deformation. This deformation does not just make for an interesting landscape but also affects the shape of mineral grains in the rock. The shape of grains can show us the amount of tectonic compression or extension the region has experienced, however the grains only record the amount of strain since it formed. Using quartz veins and the quartz grains that compose them, I measured the minor/major axis lengths of the grains. This shows us how the grain has been stretched or compressed relative to the veins orientation. The main method used for this analysis is the Fry method and it allows us to see the amount of compression or extension has occurred along the quartz veins. The results show us that if veins have not be cross cut then the grains are compressed along the vein orientation and extension occurs perpendicular to the vein orientation. When a vein does get crosscut, then the grains show less extension perpendicular to the vein and less compression along the vein orientation. This tells us that on the vein level, when a vein crosscuts another vein, there is strain accumulated parallel to the crosscutting veins orientation. This research will help complete the picture of the total amount of strain built up in the Butte, Montana region.

Influence of Misfolded Proteins on the Growth Pathway in Budding Yeast

Presenter(s): Zachary Basham

Faculty Mentor(s): David Garcia

Poster 3

Session: Sciences

Prions are misfolded proteins that have developed a negative connotation due to their involvement in many degenerative diseases. However, some prions have been found in yeast that result in benefits for the cell. This experiment focused on a specific prion that gives rise to larger cells with increased replication rate. We hypothesized that the prion must be interacting with a pathway that regulates the maturation of the cell. To determine the cause of this phenotype, we grew cells in the presence of rapamycin, an inhibitor of the TOR (Target of Rapamycin) complex which regulates the growth of cells by modifying proteins. By recording the absorbance of cell cultures with and without the prion, we were able to determine the growth rate and support the claim that the misfolded protein is influencing TOR because they showed resistance to the drug. The next step is to determine what is being affected in the complex to provide this result. Understanding how prions work on a molecular level may reveal new cell functions not possible by genetics alone.