Category: Poster Presentation

Installation and Preliminary Use of Lunt Solar Telescope at Pine Mountain Observatory

Presenter: Nico Tuton-Filson – Physics

Co-Presenter(s): Jackson Robinson

Faculty Mentor(s): Scott Fisher

Session: (In-Person) Poster Presentation

Pine Mountain Observatory (PMO) has been operated by the University of Oregon for many years, recently expanding with new fields of observation, such as solar observation. Through our partnership with the Allan Price Science Commons & Research Library, our lab acquired a solar telescope in early 2021. This is the first solar telescope to be installed at the observatory, and therefore our lab team is learning how to best utilize this new equipment. Our end goal is to capture live images of solar activity and share them online in real-time. Through independent research and preliminary data collection, we have worked towards finding the optimal procedure for capturing and processing images. By the end of the summer 2022 we will be finalizing the installation and automation of the telescope and its image processing system. This work is vital to the University because it will create new research opportunities for future undergraduate students and provide an online resource to be used in classrooms at UO and beyond.

Effects of Rangeland Compost Amendments on Nematode Abundance

Presenter: Maya Treder – General Science

Faculty Mentor(s): Ashley Shaw, Lauren Hallett

Session: (In-Person) Oral Panel—Fuel, Fire, Grass and Compost, Poster Presentation

California rangelands are often over-grazed, nutrient-depleted, and subject to variable rainfall. Compost amendments are gaining popularity as a management tool due to their potential for soil carbon sequestration. Despite positive effects on plant growth, little is known about how soil communities respond to these amendments, especially across variable precipitation conditions. Nematodes are excellent indicators of soil community responses as they span every trophic level and are sensitive to changing environments. Here, we examined how amendment treatments (compost, fertilizer, none) affect nematode communities across variable precipitation conditions (drought, irrigation, wet). We hypothesized: 1) amendments increase nematode abundance, where compost has a greater positive effect than fertilizer; 2) nematodes respond positively to elevated soil moisture and negatively to drought; 3) effects of amendment and precipitation are interactive, where compost mitigates drought’s effects on nematodes. As expected, compost increased nematode abundance relative to other amendment treatments. However, overall, nematodes were most abundant under ambient precipitation, contrary to expectations. This was due to the precipitation-amendment interaction. While compost and fertilizer had similar positive effects on nematodes under ambient and irrigation, under drought, fertilizer had a negative while compost had a positive effect on nematode abundance compared to the no amendment treatment.

Molecular Dissection of the SHIP1 Phosphatase

Presenter: Pilar Tosio – Psychology

Faculty Mentor(s): Grace Waddell

Session: (In-Person) Poster Presentation

The 145 kDa lipid phosphatase SHIP1 is a critical component in immune cell signaling pathways and allows hematopoietic cells to undergo chemotaxis. Although the enzymatic role that SHIP1 plays in the dephosphorylation of phosphatidylinositol-3,4,5-phosphate (PI(3,4,5)P) lipids is understood, much remains unknown about the role SHIP1 plays in the excitable signaling network. Using TIRF microscopy, we can observe SHIP1 being recruited to the plasma membrane where the protein can be activated and inactivated. How this lipid phosphatase is being localized to the plasma membrane is not yet understood. We hypothesized that the region responsible for SHIP1 localization exists within the SHIP1 C-terminus. By performing a molecular dissection of the SHIP1 phosphatase, we determined that the last 110 amino acids of SHIP1’s C-terminus is required for SHIP1 to display polarized membrane localization patterns in human neutrophils. This finding has helped to elucidate the biochemical underpinnings of immune cell migratory functions.

Exploring the Role of the Arp2 D-Loop in Activation of Arp2/3 Complex

Presenter: Maisie Topping – Biochemistry

Faculty Mentor(s): Brad Nolen, Heidy Narvaez Ortiz

Session: (In-Person) Poster Presentation

Branched networks in the actin cytoskeleton are critical for a variety of cellular processes including endocytosis. New branched actin filaments are nucleated by Arp2/3 complex, and the deregulation of this protein is related to diseases such as cancer. Arp2/3 complex is intrinsically inactive. During activation, the complex undergoes a conformational change that brings two of its subunits, the actin-related proteins Arp2 and Arp3, into a position that mimics two consecutive actin subunits within a filament, thereby creating a template for the new filament. When actin polymerizes into filaments, a portion of the protein called the D-loop helps to stabilize the filamentous structure, and the Arp2 and Arp3 subunits both contain a similar D-loop. A previously solved structure of Arp2/3 complex at a branch junction indicates that a contact between the D-loop of Arp2 and ArpC3 may be important for stabilizing the activated complex at the junction site. This project aimed to assess the importance of that contact in activation of Arp2/3 complex. We generated a strain of budding yeast with three mutations in the Arp2 D-loop, purified Arp2/3 complex from cells, and used pyrene actin polymerization assays to test the ability of the mutated complex to nucleate actin filaments compared to the wild type. The Arp2 triple mutant showed greatly decreased activity, indicating that the contacts between Arp2 and ArpC3 are important for the activation and function of Arp2/3 complex.

Developing an In Vivo Assay for Quantitative Analysis of Arp2/3 Complex Inhibitors

Presenter: Maisie Topping – Biochemistry

Faculty Mentor(s): Brad Nolen, Heidy Narvaez Ortiz

Session: (In-Person) Poster Presentation

Branched networks in the actin cytoskeleton are critical for a variety of cellular processes such as motility and endocytosis. New branched actin filaments are nucleated by Arp2/3 complex, and the deregulation of this protein is related to a variety of diseases including cancer. Several classes of small molecule inhibitors of Arp2/3 complex have been discovered, most of which function by blocking an activating conformational change of the complex. These molecules are useful tools because they allow researchers to turn off activity in different processes, and they have potential as drugs due to Arp2/3 complex’s increased activity in some diseases. These inhibitors have been characterized in vitro and have been used in experiments, but they have never been quantitatively analyzed in vivo. My project will develop an in vivo assay for quantitatively measuring the effects of Arp2/3 complex inhibitors on cytoskeleton dynamics. The assay will use Drosophila S2 cells expressing a low level of GFP-tagged actin and total internal reflection fluorescence (TIRF) microscopy to extract velocity data from the cell’s actin cytoskeleton before and after treatment with inhibitors. These experiments will lead to a better understanding of how Arp2/3 complex inhibitors affect living things because this assay is a better approximation of biological systems than the currently used in vitro methods. The different assays can be used in concert to provide a fuller characterization of these inhibitors.

Visualizations of the IP Address Space with Hilbert Curves to Expose Multifractal Patterns

Presenter: Eugene Tan – Computer and Information Science

Faculty Mentor(s): Reza Rejaie, Chris Misa

Session: (Virtual) Poster Presentation

A critical challenge in understanding the traffic flowing through modern computer networks is the visualization of traffic features associated with a large number of networked devices. These observed IP addresses from these devices are known to cluster within IP address prefixes formulating a multifractal structure. Leveraging the Hilbert curve we simultaneously visualize the multifractal structure of these observed addresses and the traffic features associated with each address, enabling new observations to be made by combining both aspects of network traffic data into a single visual presentation. This is done through the Hilbert curve’s property of locality which enables addresses sharing the same prefix to be mapped to similar locations within the curve resulting in observable clusters in regions of the visualization. We approach this challenge by implementing this visualization tool of mapping addresses to the Hilbert space, utilizing color theory to draw visual feature relationships and patterns that may appear. Therefore, the primary goal of this work is to leverage this visualization tool to examine the relationships between traffic features and the multifractal distribution of observed addresses through a series of case studies.

The Role of Verbalization in Hierarchical Control

Presenter: Emily Stutz – Psychology

Faculty Mentor(s): Melissa Moss, Ulrich Mayr

Session: (In-Person) Poster Presentation

 Performing complex tasks usually requires the cognitive system to handle rules at multiple levels of abstraction, where lower-level rules depend on the status of higher-level rules (e.g., a child may be allowed to eat with her fingers at home, but use silverware in a restaurant). Previous work has identified verbalization (“inner speech”) as critical for such hierarchical control in the context of situations that require following a sequential plan. However, this work did not assess the need for inner speech in the context of non-serial, or cue-based tasks. Further, only relatively simple, two-level hierarchical control sequences were used. The current study used articulatory suppression to assess whether verbalization is important when handling complex serial-order and cue-based hierarchical tasks. Participants executed tasks with one, two, or three levels of either cue-based rule complexity or sequence complexity, while performing a secondary task that manipulated verbalization demands (articulatory suppression versus foot-tapping). Surprisingly and contrary to previous findings, we did not find a decrease in performance in either the cue-based or the sequential tasks with articulatory suppression. These results seem to indicate that hierarchical control does not require inner speech. Potential reasons for the discrepancy with the previous literature results are discussed.

Investigating sexual dimorphic P-granule structures during germ cell development in C. elegans

Presenter: Madison Studer – Neuroscience

Faculty Mentor(s): Acadia DiNardo, Diana Libuda

Session: (In-Person) Poster Presentation

Proper egg and sperm development is crucial for the faithful passage of the genome from one generation to the next. To prevent infertility and genomic instabilities linked to congenital disabilities, the process of sperm and egg development is tightly regulated by small RNA pathways. These pathways silence genes that disrupt the genome and maintain silencing across generations independent of DNA sequence, termed transgenerational epigenetic inheritance. In Caenorhabditis elegans, the components of small RNA pathways localize to P-granules, liquid-like condensates that form around the nuclei of developing sperm and eggs. ZNFX-1, a recently discovered structural P-granule component, is required for genome maintenance and fertility. Although ZNFX-1 is known to be involved in transgenerational epigenetic inheritance during egg development, the role of ZNFX-1 during sperm development remains unknown. Preliminary data from the Libuda Lab suggests that ZNFX-1 has sex-specific localization, indicating distinct sex-specific mechanisms for genome maintenance in egg and sperm development. To determine the sexually dimorphic localization patterns of ZNFX-1 during sperm and egg development, I am examining GFP-tagged ZNFX-1 localization in wild type and mutant P-granule strains. This work will reveal the sex-specific role of ZNFX-1 in small RNA pathways and provide insights into the molecular mechanisms that maintain genomic integrity and fertility.

Regulation of the Kynurenine Pathway in Neurospora crassa

Presenter: Haley Speed – Biology

Faculty Mentor(s): Eric Selker

Session: (In-Person) Poster Presentation

The kynurenine pathway is a metabolic pathway that degrades tryptophan into NAD+ and several other essential biomolecules. In humans, the kynurenine pathway is closely tied to healthy and disease states, and current research indicates that altering the activity of the pathway could have therapeutic benefits. This ancient pathway is also conserved across all eukaryotes. Previous work from the Selker lab using the filamentous fungus Neurospora crassa as a model organism suggested that the regulation of this pathway is intertwined with general chromatin control processes, including H3K36me and chromatin remodelers. My research aimed to identify novel regulatory factors affecting this pathway. I used a phenotypic screen of the Neurospora Functional Genomics Project strains. In addition, RT-qPCR analyses of RNA for kynurenine pathway enzymes helped reveal which strains were abnormally inducing the pathway. In total, five genes of interest have been identified as potential regulators of the kynurenine pathway, including one factor also tied to MAPK pathway induction. Further research is needed to characterize these genes to understand how they may function to regulate the kynurenine pathway, or if their regulatory function is tied to chromatin control.

Utilizing Drosophila to investigate novel regulatory pathways for the Hox gene Sex Combs Reduced

Presenter: Alanna Sowles – Neuroscience

Faculty Mentor(s): Kristen Lee, Chris Doe

Session: (In-Person) Poster Presentation

Across species, Hox genes are necessary for an organism’s anatomical development, including the nervous system. Interestingly, these proteins continue functioning within neurons of mature organisms. This research seeks to determine the functional purpose of Hox genes post-development, as these mechanisms could provide novel etiological insight into neurodevelopmental disorders. Drosophila melanogaster is an effective tool for this investigation because fly neurons are similar to mammals, and gene expression of individual neurons is easily manipulated. Within this model, I will utilize the well-characterized Pair1 pre-motor neuron, which expresses the Hox gene Sex combs reduced (Scr). I hypothesize that Scr is functioning in a conserved molecular pathway to preserve the morphology and function of Pair1 neurons. Past research provides intuitive candidates for exploring these mechanisms, like Pair1 proteins Hb and Bcd. RNAi-facilitated knockdown had no significant impact on Scr expression, prompting exploration of alternative genes. Using published resources, several genes with expression patterns similar to Scr were selected and visualized with GFP-tagged proteins. Colocalization of these genes with Scr was assessed via immunohistochemistry, revealing 8 promising candidates for further analysis. Scr expression will be measured after knockdown experiments are repeated for each gene. The results will hopefully illuminate novel regulatory pathways of Scr beyond development.