Category: 2012

The Role of Chromatin Remodeling Complex in Valve Development

Presenter: Maithri Sarangam

Mentor: Kryn Stankunas

AM Poster Presentation

Poster 43

Congenital heart diseases are one of the most common types of birth defects. Studying the development of this complex organ may provide insight into the causes of such defects. It has been shown that chromatin remodeling complexes play a role in directing developmental processes. They affect expression of genes by modifying chromatin, the DNA-protein complex in the nucleus. One particular chromatin remodeling complex, the BAF complex, has been shown to be important in heart development. We believe the BAF complex is required during the remodeling and elongation phase of aortic valve development. The aortic valve controls blood flow from the heart through the aorta. We used mouse models and complex genetic techniques to study the role of the BAF complex in mammalian heart valve development. Using a crelox system, we induced a loss of function of the BAF complex in endocardial cells, which make up the lining the heart, by knocking out Brg1, the key ATP-ase required for the complex to function. We then used various histological and immunofluorescence stains to study the resulting phenotype at different time points during the elongation and remodeling phase. The aortic valve phenotypes in the mutant embryos deviated from that of their wild type litter-mates, suggesting that the BAF complex does have a role in this phase of valve development.

Inaccurate Grip Predictions for Congenital Amputees’ Absent Hand: Evidence of Sensory-dependent Construction of Accurate Internal Models for Motor Planning

Presenter: Samantha Ross

Mentor: Marjorie Woollacott

AM Poster Presentation

Poster 41

To what extent does accurate internal model construction, for motor planning, depend on sensory experience? A previous study showed preserved accuracy of models for traumatic amputees’ absent hand (Philip & Frey, 2011). We investigated whether accurate internal models depend on initial limb presence. Five congenital upper limb amputees and matched controls performed two grip selection tasks: overt grip selection (OGS), where participants explicitly grasped a presented stimulus with their intact hand; and prospective grip selection (PGS), where judgments were made for either hand while remaining stationary. Predictive accuracy was calculated by comparing PGS directly to OGS for intact hand, and to the inversed OGS for absent hand. Amputees did not signifi- cantly differ in overall accuracy from controls [F(1,4)=4.49, p=0.10], or between hands [F(1,4)=0.13, p=0.74]. However, a significant accuracy-orientation pattern for amputees’ absent hand, [F(1,4)=7.908, p=0.048] was found. This suggests amputee’s directly use their intact hand for decisions about absent hand, supporting sensory-dependent construction of internal hand models for motor planning.

Dietary Intake and its Effect on Muscle Atrophy Post Total Knee Arthroplasty

Presenter: Alexander Robinson

Mentor: Hans Dreyer

AM Poster Presentation

Poster 39

Post-operative muscle loss has been singled out as the greatest contributor to long-term strength deficits, explaining 77% of muscle weakness 1-3 years after total knee arthroplasty (TKA). One possible factor contributing to significant and rapid loss of muscle occurring within two weeks of surgery is reduced dietary intake during which our body breaks down skeletal muscle protein in order to liberate amino acids for use as gluconeogenic precursors in the liver. Therefore, inadequate dietary intake may exacerbate muscle loss following surgery. I hypothesize that subjects who maintain a protein intake ≥ .8g/kg or ≥ 2000 calories a day will experience less muscle atrophy following surgery. For this study, subjects completed a total of three 3-day food logs at baseline, 2 and 6 weeks post-TKA. Furthermore, at these same time points bilateral quadriceps muscle volume was determined using MRI. Also baseline and 6-week whole body DEXA scans were performed to determine changes in lean tissue and fat mass. Our preliminary data show at two weeks following surgery caloric and protein ingestion has decreased. Also there is a 16% decrease in lean muscle mass of the quadriceps two weeks after surgery, and this decrease may be partially explained by insufficient dietary intake.

X-Ray Crystallography of CUG-Containing RNA Constructs with and Without Small Molecules Could Help Develop Therapeutic Agents to Alleviate Myotonic Dystrophy Symptoms at a Molecular Level

Presenter: Irina Rapoport

Mentor: Andy Berglund

AM Poster Presentation

Poster 37

Myotonic dystrophy is the most common form of adult-onset muscular dystrophy. DM type 1 is caused by aberrantly expanded CTG repeats in the 3’ untranslated region of the DMPK gene. Upon transcription, toxic RNA CUG repeats are formed, which sequester Mbnl proteins, causing abnormal splicing in cells. Some of these abnormal splicing events have been shown to lead to the disease symptoms. Small molecules that release Mbnl sequestration from the toxic RNA could alleviate disease symptoms. I am crystallizing CUG-containing RNA constructs with and without small molecules. Crystal structures would provide direct evidence of where and how the small molecules bind the toxic RNA. Before crystallography, the RNA is deprotected, purified by HPLC, resuspended in buf- fer and annealed. Using Natrix crystallization screens, I test a wide array of conditions for crystal formations. Then, I scale up and vary the most favorable conditions to obtain bigger crystals. Two different RNA constructs, containing three CUG repeats, have crystal- lized well without small molecules under several conditions. A third RNA construct, with two CUG repeats, formed crystals with a small molecule called JFA12046. To screen for additional small molecules with the ability to disrupt the MBNL-CUG complex, we are running competitive electrophoretic mobility shift assays. Long-term, efficiently designed small molecules could be used as therapeutic agents to treat myotonic dystrophy and other diseases with similar molecular mechanisms.

A Look at the Development of Action Segmentation in Children and Adults

Presenter: Jennifer Paternostro

Mentor: Dare Baldwin

AM Poster Presentation

Poster 35

In order to process and understand events as they unfold, adults break down events into smaller parts. For example, the process of making a sandwich would include big, medium, and small events. A big event would be completing making the sandwich, a medium event would be finishing putting the condiments onto the sandwich, and a fine event would be placing one slice of turkey onto the bread. Adults are readily able to predict the next step in a sequence of actions, such as predicting that the cheese will go on top of the meat in the sandwich example. The present research investigates developmental differences in how humans predict action. We hypothesize that when adults are processing an action sequence, they tend to look longer at the end of that sequence as they actively make predictions about the next step. Children, however, may be slower to predict what will happen next and therefore will have longer looking times at the beginning of each additional sequence. Specifically, this study explores the differences in action segmentation between 3-year old children, 5-year old children, and adults. Participants advanced through a self-paced slideshow of an actor making an ice cream sundae while the computer recorded their looking times to each individual slide. Our findings point to the differences in how children and adults segment and predict action.

Environmental Leadership Program Canopy Connections Environmental Education Program 2012

Presenter: Emma Newman, Gritz Kuhn, and Kate Vannelli

Mentor: Kathryn Lynch

AM Poster Presentation

Poster 33

Canopy Connections is a project of the Environmental Leadership Program (ELP), which is a service learning program housed within the Environmental Studies Program at the University of Oregon. Eight undergraduates worked with faculty and community partners to create environmental education programs for middle school students from eight different classes from around Lane County. Canopy Connections is a partnership between the ELP, the H.J. Andrews Experimental Forest, and the Pacific Tree Climbing Institute. The Canopy Connections program was set up to give the undergraduate team an opportunity to develop day long field trips based on the theme of people and plants to teach environmental education to middle school students. The goal for this project was to educate middle school students on the fundamentals of ethnobotany through immersion in the Willamette National Forest. Undergraduate students developed their skills as educators by gaining first-hand experience with environmental education curriculum development and implementation, while also improving their collaboration, communication and leadership skills. This report highlights aspects of the Canopy Connections 2012 program. The field trip was set up as four “quests,” which are a type of scavenger hunt that together formed a comprehensive environmental education program. The undergraduates facilitated the quests at the HJA Experimental For- est by working alongside middle school students to answer questions about flora.

Mapping the Human Primary Somatosensory Cortex Using Dense-array EEG: An Analysis of the Somatosensory Evoked Potential

Presenter: Kyle Morgan

Mentor: Don Tucker

AM Poster Presentation

Poster 31

In principle, dense-array EEG (dEEG) technology has the ability to localize cortical brain activity with adequate spatial resolution such that anatomically and functionally distinct regions can be studied. The present study employs dEEG to map activity of the primary somatosensory cortex (SI), which is functionally and anatomically defined. EEG recordings were acquired from 10 participants as their thumbs were stimulated by a custom-made piezoelectric stimulator. Early components of the somatosensory evoked potential (SEP), which reflect activity from SI, were evaluated in individual participants to assess topographic distribution at the scalp. In a subset of participants, we build high-resolution electric head models that describe how current propagates from the cortex to the scalp surface, where the SEP is measured, and we use this model to localize the early SEP components. We report on the localization accuracy relative to the expected location (SI).

Culinary Study Developing Luxury Kitchen Appliance for the Middle Class

Presenter: Jordan Millar

Mentor: Jason Germany

AM Poster Presentation

Poster 29

We focused on creating food related products. I chose a method of cooking called sous vide which enables molecular gastronomy style cooking. A sous vide is a style of cooking food in a water bath inside of vacuum sealed bags which helps maintain nutrients while cooking food perfectly. The sous vide is currently limited to high-end restaurants and the wealthy, and is not affordable for the average consumer. I designed an affordable sous vide for the middle class and created a fully functional model. The benefits of the sous vide include that it slow cooks food to perfection, it is easy to use, is safer than other cooking methods and it brings families together to prepare restaurant quality food in the home. I created the model using a laser cutter, vacuum former, foam modeling, glass grinding, 3D printing, CNC and silicone molding, and wiring components. Using simple parts and a compact construction, I was able to create a functional sous vide that is affordable for home use that is easy to use and aesthetically pleasing, while enabling the highest quality cooking results.

Hold the Door! Preventing Mildew in a Shower Room

Presenters: Tyler Mavichien and Regan Greenhill

Mentor: Matt Hogan

AM Poster Presentation

Poster 27

When a sign stating to leave the door open after showers to prevent mildew was placed on the door to the shower room in a cam- pus residence hall, residents wondered why it was necessary especially because of the multiple air vents located in the shower room. The question formed from this observation and the basis of our case study was: would leaving the door to the shower room open lower the rate of humidity more than leaving the door closed? We tested the intake rate of the vents and measured the humidity the showers created with Hobo U12 Datalogger. After surveys of the residents were conducted to find the average length of the shower, 12.5 minutes, three scenarios were tested. First, running the shower for 12.5 minutes with the door closed the entire time and leaving the door closed 30 minutes after water has stopped. Second, running the shower for 12.5 minutes with the door closed the entire time then opening the door for 30 minutes after water has stopped. Third, a worst-case scenario of running all three shower heads at the hottest setting for 15 minutes with the door closed the entire time and leaving the door closed 40 minutes after water had stopped. Finally, a long term test was conducted over five day measuring regular usage. Our results showed that humidity levels did not stay above 60% for more than an hour, the level at which mildew starts to grow. Our case study proved the intake vents are effective in preventing mildew from growing and the added sign is unnecessary.

Shaping the Face: Genetic Interactions in Zebrafish Jaw Development

Presenter: Braden Larson

Mentor: Charles Kimmel

AM Poster Presentation

Poster 25

Development of the jaw skeleton can be divided into three stages: (1) migration of neural crest cells, precursors of jaw skeletal cells, (2) aggregation of neural crest cells into pharyngeal arches, and (3) differentiation of pharyngeal arch cells into skeletal cells. Signaling between cells is instrumental in all three stages. One signal, Endothelin-1 (edn1), is known to be required for lower jaw development in zebrafish. Work in mice has shown that the signaling molecule Fibroblast growth factor-8 (fgf8) is required for proper edn1 expression, motivating the following hypothesis: edn1 and fgf8a genetically interact in zebrafish jaw development. / We tested this hypothesis by generating fish that carry mutations in both edn1 and fgf8a. These fish are missing cartilage cells from their upper jaw, a phenotype not present in either single mutant. To investigate the cause of this phenotype we examined cells of the pharyngeal arches. We found that the first arch, which is the precursor to the lower and upper jaw, to be dysmorphic. We then examined neural crest cell migration. While migration appeared normal, neural crest cells failed to aggregate into the intermediate region of the first arch in double mutant fish, placing the manifestation of the double mutant phenotype in stage two of jaw skeleton development. Our findings suggest a novel genetic interaction or synergy between edn1 and fgf8a in which they function to promote aggregation of neural crest cells into the intermediate region of the first pharyngeal arch.