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Undergraduate Research Opportunities Program

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Motor Learning in a Goal-Oriented Visuospatial Task

2021-12 , Williams, Erin Skyler

There have been numerous studies that investigate motor learning at large, but there is a lack of research focusing on three-dimensional visuospatial learning and action observation in the setting of a goal-oriented motor task. There are even fewer that test these variables while introducing a social component in which the subject must execute motor control based off another person’s directed movements. The objective of this study is to investigate how factors, such as action observation, social intention, motor control, and goal-oriented behavior impact motor learning of a subject during a structure building task. Twelve right-hand dominant subjects engaged with the researcher during two rounds (each consisting of 15 trials) with each round resulting in a static structure that the subject constructed by imitating the movements of the researcher. Half of the subjects completed this paradigm while wearing a transradial body-powered prosthetic simulator device on their right arm (experimental group) to test if the prosthesis altered motor learning. The research questions aimed to assess subjects’ ability to display evidence of motor learning throughout the task, if this evidence is associated with increased gaze position in the researcher’s quadrant, and if these trends remain consistent when subjects are wearing the prosthesis. Eye-gaze patterns, task completion time, performance and task errors, and behavioral observations were used as methods of data collection, and statistical analyses, including t-tests, sample means, and surface distributions, were performed to evaluate the hypotheses. Results revealed subjects in both groups demonstrated motor learning between round one and two, and while the addition of the prosthesis increased task completion time and error values, subjects within the experimental group were also able to demonstrate significant decreases in the latter round. In addition, eye-tracking data revealed increased gaze patterns on the researcher’s path of movement vs. the quadrant itself for the experimental group compared to the control group. This suggests that social intent and action observation are likely facilitating an increase in motor learning in subjects tasked with completing goal-directed movements with the unfamiliar prosthesis.

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Salivary Micro RNA as a Biomarker for Concussion Symptoms in Pediatric Patients

2021-05 , Bryant, Graham G.

This research project employs an untargeted approach using RNA sequencing to identify miRNA in saliva following a traumatic brain injury, specifically a concussion, to better understand how acute brain injuries can be diagnosed and treated. There is currently no biological test in place for diagnosing concussions, which are one of the most frequently observed sport related injuries. This study is invested in determining novel molecular biomarkers in saliva that are associated with concussion so that they can then be correlated with symptoms of concussion. The study predicted that salivary miRNA levels are altered in children with concussion, and there will be a significant difference in levels of miRNA at baseline (pre-injury) and post-injury in athletes. By determining novel biomarkers, noninvasive saliva testing may help to better identify concussions and prevent premature return to play as well as a better understanding of injury mechanisms.

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Purification of N-glycosylated E-Cadherin Proteins through Biotinylation Isolation of E-cadherin protein for glycomics study through biotin affinity purification

2021-05 , Patel, Roshni R.

In this study, we use Xenopus embryos to study the dynamics of neural crest cell migration. This process is important in embryonic development because it initiates the differentiation process of the embryo as a whole. The cell migration is due to the Epithelial to Mesenchymal Transition. For our purposes, we want to study how E-Cadherin changes throughout this migratory process. In particular, the complex sugars (glycans) that are attached to these proteins will be purified and sent for glycomic analysis. My project was not finished due to COVID-19 setbacks. However, we have created a Recombinant DNA construct that has attached an avi-tag to the ends of the E-Cadherin protein sequence. We are currently working on confirming that the construct has been incorporated correctly.

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Anticipating Explicit Motor Learning by Assessing Arousal Levels using HRV and GSR

2021-05 , Cox, Olivia

Biometrics, including heart rate variability (HRV) and galvanic skin response (GSR), are already used to gauge autonomic regulation, emotional reactivity, attention, and flow, a concentration state. Given the role of arousal seen in motor learning factors such as optimal stress, anxiety, and task engagement, this study investigates whether HRV and GSR show distinguished patterns in those who explicitly learn a hidden sequence in a motor task as compared to those who only learn implicitly. This is done using a serial reaction time task (SRTT) and the collection of electrocardiogram (ECG) and GSR data throughout the task then comparing qualitative data across subjects. HRV decrease and GSR increase are noted at serval instances of explicit motor learning emergence, and even in instances when the shift is not exaggerated, it is never found varying in the opposite direction as the hypothesized pattern. Despite a low participant sample size and a low sampling frequency for ECG and GSR, the results tentatively support the concept of using HRV and GSR to gauge whether or not a person’s current state is conducive to explicit motor learning. This biometric monitoring holds the potential for real-time biofeedback and could be useful in physical rehabilitation settings due to the relative ease of implementation.

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An investigation into the multiple Type VI Secretion Systems of Enterobacter cloacae

2021-05 , Wilson, Ashley

Enterobacter cloacae is a Gram-negative, opportunistic bacterial pathogen that is commonly acquired by patients in hospitals. The Type VI Secretion System (T6SS) is a harpoon-like apparatus that injects toxins into the cell envelop of neighboring bacteria to defend or compete for resources. It’s commonly found in a range of bacteria including Vibrio cholerae, Pseudomonas aeruginosa, and Escherichia coli. Previous research in this lab has shown that E. cloacae kills in a contact dependent manner and bioinformatic analysis found three vask genes, which encode for a protein in the Type VI apparatus. We created three single mutant strains (Δvask1, Δvask2, Δvask3) as well a double mutant (Δvask1Δvask3). These strains were tested in competition assays with target WT E. coli, with the survival of the target being indicative of E. cloacae killing ability. We show here that Δvask2 had no change in killing ability, Δvask1 and Δvask3 had some reduction in killing ability, and Δvask1Δvask3 had a complete reduction in killing ability. This initial result suggests E. cloacae in vitro killing ability is dependent on two T6SSs.

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Probing the Dynamic Nature of Mycobacterial Heme Homeostasis

2021-05 , Hale, Owen Francis

Mycobacterium tuberculosis is responsible for more human deaths every year than any other bacterium. In order to establish an infection and cause disease, M. tuberculosis requires the nutrient heme. Heme is essential for numerous processes within the cell but is also cytotoxic, so its synthesis, uptake, and utilization must be tightly regulated by the bacterium. Despite the important role of this nutrient, relatively little is known about the regulation of its abundance and bioavailability. To better understand heme dynamics in mycobacteria, a total heme fluorescence assay and genetically encoded exchange labile heme sensors were used to observe changes in the abundance and bioavailability of heme in Mycobacterium smegmatis under various conditions. These experiments demonstrate that heme abundance and bioavailability in mycobacteria can change in response to physiologically relevant stresses and environmental cues.

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USING ASCORBIC ACID AND HIGH SALINITY TO EXTEND THE VIABILITY OF PROALES SIMILIS (ROTIFERA) DIAPAUSING EGGS

2021-05 , Brashear, Jillian

Rotifers are sensitive indicators of environmental conditions and serve as model organisms for assessing toxicity. It is understood that rotifer cysts (diapausing eggs) are convenient for toxicity assessment because they remove the need to maintain animal cultures, reduce variability in tests, and can be stored for on-demand use. Indeed, cyst-based toxicity tests for the rotifer Proales similis have helped to fill a need for an additional marine animal model to the rotifer Brachionus plicatilis in ecotoxicology. A challenge to implementing tests is the need for readily- available P. similis diapausing eggs, which need to be reliably preserved and hatched on demand. This study explores preservation methods to extend the viability of P. similis eggs. We explore factors including storage temperature, salinity, and the addition of ascorbic acid to measure their effects independently and combined. We found that storing the diapausing eggs at approximately 4℃ in the presence of 20µM ascorbic acid and a 220ppt salinity is effective for extending egg viability. With longer viability, P. similis diapausing eggs are more readily available and thereby valuable as a tool in toxicity assessments.

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Single particle cryo-EM structure elucidation of a Photosystem II complex mimicking a critical step in photoinhibition

2021-05 , Espy, Carolann Lindsay

Photosystem II (PSII) is an essential protein in the photosynthetic process that houses the oxygen evolution center, which is responsible for producing most of the oxygen in the atmosphere. In order to better understand PSII and its function, it is important to discern the structure of active PSII and the process of photoinhibition. Photoinhibition occurs when the extrinsic subunits are damaged due to overexposure to light, and are then removed, repaired, and replaced. The removal of these extrinsic subunits could be recreated with the help of a urea wash protocol, which removed subunits PsbO, PsbP, and PsbQ. The method used here to elucidate the structure of urea wash PSII, was electron cryo-microscopy (cryo-EM). Utilizing this method and a gentle purification of the protein, a 3D model of an important step in the repair of ‘photoinhibited’ PSII was obtained. Through testing multiple parameters during image processing, several models were generated with estimated resolutions ranging from 20.74 Å to the best estimated resolution of 9.05 Å (Figure 2).

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Impact of parrotfish predation on coral health: changes in microbiome and pathogen defense

2021-05 , Towner, Alexandra

Coral reefs are in rapid decline, and it is imperative to study reef community interactions in order to mitigate and reverse this trajectory. This study explores the relationship between corals and parrotfish, investigating how parrotfish bites on coral impact the composition of the coral’s microbiome and the corals suppression of a common bacterial pathogen. Fragments of Porites lobata coral colonies that were heavily predated by parrotfish or that showed no signs of parrotfish predation were shaken in seawater, and this seawater was bioassayed against the common coral pathogen Vibrio coralliilyticus to assess the effects of previous predation on the coral’s ability to suppress this ecologically relevant pathogen. Additionally, we sequenced the 16S rRNA gene from each coral sample to investigate possible alterations of the coral’s microbiome due to predation. Neither alpha diversity nor beta diversity of the microbiome was impacted by parrotfish predation. However, some bacteria were differentially abundant, such as those of the genus Endozoicomonas. Bioassays of water in which coral fragments were agitated detected no impact of previous parrotfish attack on the coral’s suppression of the pathogen Vibrio coralliilyticus. Overall, this speaks to the resistance and strength that corals demonstrate in the face of parrotfish predation.

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The Potential Role of Kv3.3 in Chemotherapy-Induced Neuropathy

2021-05 , Pfahl, Emily Lynn

Oxaliplatin (OX) is a widely used chemotherapy compound used in the treatment of colorectal cancers (CRCs). Patients treated with OX often exhibit severe side effects, including motor dysfunction and imbalance, potentially influenced by the inability of sensory neurons, including muscle spindle afferents (MSAs), to repetitively fire, which is needed to properly encode information about limb movement. Even though OX is prescribed in a majority of CRCs, it is currently unknown how the compound causes the aforementioned side effects. The aim of the present study was to determine if OX acts through modification of the voltage-gated potassium channel Kv3.3, which is hypothesized to promote repetitive firing. To test this hypothesis, the soleus nerve and muscle were isolated from control mice. A series of ramp and triangular stretches were applied to the muscles, and afferent firing responses were recorded. A synthetic Kv3.3-knockdown line of mice was created using Kv3.3 siRNA (ThermoFischer Scientific). The soleus nerve and muscle were isolated from these mice, the same stretches were applied to the muscle, and MSA recordings were taken and compared to the control MSA responses. Preliminary data suggest that afferent responses to stretch are altered in the Kv3.3-knockdown mice, but as of this time, not enough data has been collected to make statistically significant claims. Future work will focus on collecting enough Kv3.3-knockdown data to perform statistical analyses on the data, as well as on performing immunohistochemical (IHC) staining of tissue from knockdown animals to ensure silencing of Kv3.3.

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