2019 O'Day Fellowship Recipients
Undergraduate: Emily Hill Graduate: Kaye Shek
Title: Linking mycorrhizal fungal diversity with pathogen abundances in a vineyard agroecosystem
PI Lab: Krista McGuire
Undergraduate: Jeanette Helgerson Graduate: Doug Foote
Title: Differences in Old and Young Patient Myoblast and Myotube Responses to Amino Acid Stimulation
PI Lab: Hans Dreyer
Undergraduate: Rennie Kendrick Graduate: Lea Frank
Title: The Effect of Blocked vs. Interleaved Training on Associative Inference
PI Lab: Dasa Zeithamova
Undergraduate: Sydney Kobak Graduate: Dylan Sieck
Title: Histamine and Cardiovascular Adaptation to Endurance Exercise
PI Lab: John Hailliwill
2018 O'Day Fellowship Recipients
Undergraduate: Chaucie Edwards Graduate: Matthew Ely
Title: Exercise-induced Elevations in Skeletal Muscle Histamine Contributes to Increased Post-exercise Capillary Permeability
PI Lab: John Halliwill
Abstract: Histamine, an endogenously released molecule in immune and inflammatory responses increases local vasodilation, blood flow, and capillary permeability. During exercise, histamine is produced within exercising muscle and contributes to an elevated post-exercise blood flow. The histamine-induced post-exercise vasodilation is contained within previously exercised muscle as histamine concentrations are not elevated in non-exercised muscle (i.e. arms during leg exercise). It is unknown if intramuscular histamine also contributes to elevate capillary permeability following exercise. PURPOSE: To compare capillary permeability of the leg before and after prolonged unilateral knee-extension exercise under normal conditions and when histaminergic signaling is blocked. It was hypothesized that H1/H2 receptor antihistamines would decrease capillary permeability following exercise in an exercised leg but not in a resting leg.
Undergraduate: Brynna Paros Graduate: Jonathan Saunders
Title: Reopening Auditory Critical Periods by Digesting Perineuronal Nets
PI Lab: Michael Wehr
Abstract: Long-term memories are thought to be encoded by synapses, but synaptic proteins recycle within days. Roger Tsien hypothesized that Perineuronal Nets (PNNs) could provide a durable “punch card” for memory storage. PNNs are tightly-regulated protein lattices surrounding some neurons that inhibit new, while maintaining existing synapses. Understanding speech requires learning the low-level acoustic features of a language, which becomes difficult or impossible after a developmental sensitive period. Do PNNs preserve the acoustic features learned during infancy and inhibit learning new sound categories? Our preliminary experiments demonstrated that the enzymatic digestion of PNNs in auditory cortex enabled mice to learn a distinction between english phonemes (/b/ and /g/) that they were previously unable to. We will present these and other pilot data investigating the effect of PNN digestion on the rate of phonetic acquisition. If PNNs serve as a scaffolding to preserve learned low-level sensory representations, they would be an entirely unexplored therapeutic target for children or elderly people with sensory processing impairments, as well as provide a promising new explanation for the mechanistic origin of developmentally sensitive or critical periods.
Undergraduate: Kieley Trempy Graduate: Kate Spitzley
Title: The role of limb dominance in visuoproprioceptive tasks
PI Lab: Andrew Karduna
Presentations Associated with Project:
International Society of Biomechanics and American Society of Biomechanics Combined Meeting
Abstract: Movement is the product of sensory input, mainly from vision and proprioception, and motor output. Vision is the sense of the surrounding space and proprioception is the sense of the body’s position in space. Joint position sense (JPS) is commonly used as a measure of proprioception. JPS of the dominant and nondominant shoulder was measured in healthy subjects to quantify error in a JPS task with and without visual information. Previous studies have examined sensory differences in limb dominance with conflicting results. Some have shown that no differences exist, while others show that movements with the dominant arm rely more on visual information and movements with the nondominant arm rely more on proprioceptive information. The latter theory is illustrated in activities of daily living, such as with preparing food, where the dominant arm uses a knife by viewing the movement while the nondominant arm guides the food by feeling the movement. It was hypothesized that in a JPS task, the dominant arm would have less error with visual information whereas the nondominant arm would have less error without visual information. Subjects wore a virtual reality headset with a tracker on their arm while performing a JPS task. Using the headset, subjects were presented with either a visual representation of their arm location or no visual information about arm location. No difference was found between sides. However, difference was seen between the vision and no vision conditions regardless of limb dominance. Higher error with no vision indicates that proprioception alone is not as effective in driving accurate movements as the combination of vision and proprioception. Future studies analyzing the contributions of vision and proprioception to movement may rule out variation associated with limb dominance.
Undergraduate: Emil Sadofsky Graduate: Matthew Schultz
Title: The effects of restoration fill elevation on carbon accumulation in Pacific Northwest estuaries
PI Lab: Scott Bridgham
Abstract: Agricultural development has significantly decreased the extent of costal wetlands in the Pacific Northwest. Some previously developed wetlands have been restored, but the effects of restoration on their carbon cycling functions are still unknown. To better understand land use effects on carbon cycling, we compared soil carbon dynamics in restored and reference wetlands in the South Slough estuary in Coos Bay, Oregon. We measured soil carbon content and used radioisotope dating to calculate carbon pools and carbon accumulation rate, and we measured in situ carbon dioxide (CO2) and methane (CH4) emissions in restored and reference wetlands to better understand carbon fluxes. To compare different methods of restoration, the restored sites were originally restored to different elevations. We found that the restored wetlands will have smaller and shallower carbon pools than reference sites. We also found that carbon accumulation will be fastest in the reference marsh. Among the restored marshes, we found that carbon accumulation is fastest in the low elevation marsh and slowest in the high marsh.
2017 O'Day Fellowship Recipients
Undergraduate: Diana Nguyen Graduate: Gabriel Yette
Title: Investigating the Role of Ezh2 in heart Development and Homeostasis
PI Lab: Kryn Stankunas
Abstract: Nearly 1% of individuals are born with a congenital heart defect (CHD), making CHDs the most common birth defect. Understanding the genetic and epigenetic underpinnings of heart development has the potential to aid in developing tools to diagnose and treat CHD. It is increasingly evident that chromatin structure and histone modifications play essential roles in heart development and homeostasis. A histone modification of interest is the tri-methylation of lysine 27 of histone H3 (H3K27me3), which is associated with gene repression. This modification is catalyzed by EZH2, the methyltransferase component of Polycomb Repressive Complex 2 (PRC2), and can be removed by Kdm6 family of demethylases. Recent work in the Stankunas lab shows that disruption of Kdm6ba and Kdm6bb in zebrafish result in smaller, poorly trabeculated ventricles of the heart. Interestingly, hearts of mice with Cre/lox dependent knockdown of Ezh2 exhibit hyper-trabeculation, ventricular septation, thinning of the ventricular wall, and aberrant skeletal muscle gene activation. These studies highlight the proper maintenance of H3K27me3 necessary for proper development. Yet, the effects of EZH2 on heart development in zebrafish has not been well explored. Zebrafish are ideal for investigating the early stages of heart development since they are transparent, and develop outside the mother, allowing for easy observation of the heart during this crucial period; elements that evades the Cre/lox system in mice. We generated an ezh2-null allele allowing us to conduct heart development studies. We hypothesize that PRC2/EZH2 is necessary to establish and maintain cardiomyocyte cellular identity by repressing developmental pathways of similar tissue types. For this project, we aim to: 1) Establish when and where EZH2 is expressed in the heart during development, and 2) Determine morphological and functional changes in developing hearts of ezh2 null zebrafish.
Undergraduate: Tabor Whitney Graduate: Diana Christie
Title: Effects of Relatedness and Habitat Fragmentation on Gut Microbial Diversity in an Endangered Primate
PI Lab: Nelson Ting
Abstract: The gut microbiome consists of microbial communities that reside in the gastro-intestinal tract of living organisms. Variation in this system has been linked to health outcomes in human and animal models by affecting digestion, immune system development, and pathogen invasion. However, we still lack a complete understanding of the factors that shape gut microbiome variation, particularly in wild primates. The central aim of this research is to further test how forest fragmentation is associated with gut microbial diversity in the Ugandan red colobus monkey. We sequenced the 16S rRNA hypervariable V-4 region to characterize the gut microbiome from 106 genotyped individuals across eight social groups inhabiting different forest types within Kibale National Park and its surrounding area. We compared alpha diversity in the gut microbiome of individuals inhabiting fragmented versus continuous forest and did not find a simple relationship between gut microbial diversity and forest fragmentation. While individuals residing in some fragments had lower gut microbiome alpha diversity, those residing in well-protected fragments retained gut microbial diversity levels comparable to residents of continuous forest. Furthermore, we discovered numerous highly related red colobus monkey dyads between forests, which allowed us to assess the affects of genetic relatedness on gut microbial similarity. We found that environment plays a larger role than genetic relatedness in shaping the gut microbiome. Our research thus reinforces the role that environment plays in shaping within-species gut microbial variation with potential implications for the conservation of threatened populations in fragmented landscapes.
Undergraduate: Jardon Weems Graduate: Nicholas Ponvert
Title: Effect of reward size on the activity of auditory cortical neurons
PI Lab: Santiago Jaramillo
Abstract: 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.
Undergraduate: Carolyn Brewster Graduate: James McDermott
Title: Nuclear Genetic Regulation of PsbA
PI Lab: Alice Barkan
Abstract: Photosynthesis provides the fuel for earth’s biomes. The protein PsbA is essential for photosynthesis but is also damaged as a consequence of photosynthesis; PsbA must therefore be constantly replaced to maintain photosynthetic activity. Accordingly, PsbA synthesis increases dramatically within minutes after shifting plants from dark to light. The mechanisms underlying this response are not known. We are investigating these mechanisms with a two-pronged approach: we are studying proteins that we suspect may be involved in PsbA light-regulation, and we are designing protein “tags” to isolate potential regulators that are attached to PsbA mRNA. We identified two candidate regulators, HCF244 and TPJ1, based on their patterns of gene expression. Using a combination of techniques, we discovered that HCF244 is required for PsbA synthesis whereas TPJ1 is not. We found that TPJ1 activates production of a different protein involved in photosynthesis. Thus, HCF244 is a good candidate for regulating PsbA synthesis in response to light, but TPJ1 is not. In the second approach, we designed a method to engineer proteins to bind specifically to the PsbA RNA. We expressed these engineered proteins in plants and confirmed that they bind specifically to PsbA RNA in vivo. We are using these proteins as “hooks” to purify PsbA RNA and the proteins bound to it. These will be evaluated for their role in PsbA regulation. In addition to elucidating mechanisms that regulate production of the photosynthetic apparatus, this is the first demonstration that proteins can be designed to purify specific RNA-protein particles from an organism.