Investigating protein interactions between pollen aperture formation factors in Arabidopsis thaliana

Pollen grains, the male reproductive structures of flowering plants, are shielded by a resilient cell wall structure called exine. Apertures are areas on the pollen surface that receive limited or no exine deposition. Their patterns vary from species to species, and they play crucial roles in pollen tube emergence during pollen germination, and in hydration of the pollen grain. In Arabidopsis thaliana, three equidistant apertures form during the tetrad stage of pollen development, when future aperture sites are created in sister microspores through delivery of specific proteins and lipids to the three equidistant domains of the plasma membrane. INP1 and INP2 are the previously characterized aperture factors that are essential for aperture formation in Arabidopsis pollen and appear to be species-specific interacting partners. In this study, we investigated the interactions between INP1, INP2, and two recently discovered pollen aperture factors. Our findings will enhance the understanding of how specific domains of the plasma membrane are created in the development of pollen apertures, with broader implications for plant reproduction and development.NSF grant MCB-2240972 (Dr. Anna Dobritsa)NSF grant MCB-1817835 (Dr. Anna Dobritsa)Undergraduate Research ScholarshipA five-year embargo was granted for this item.Academic Major: Molecular Genetic

A Quantitative Comparison of the Early Iron Age Imports in Athens and Knossos

Best Undergraduate Paper in ClassicsThis thesis presents a comparative quantitative analysis of the Early Iron Age (EIA) Near Eastern imports found in Athens and Knossos. By analyzing the significant differences in material proportions in EIA imports in Athens and Knossos, it can be concluded that because of the preference for pottery in Knossos and the preference in Athens for bronze, the original import record may be closer than only looking at the total import counts of these cities would suggest. This also ties to the conclusion that the distribution of materials in the remaining import record can be extrapolated to consider the original material composition of the import record, if provided the necessary survival and discovery rates. Additionally, the distribution of imports across time and different sites corroborates with previous research on how the preferences for Near Eastern imports in general changes across the period. By analyzing both the material and temporal composition of the import record of EIA Athens and Knossos, the comparative preferences of Near Eastern imports in these cities can be examined.Arts and Sciences Undergraduate Research Scholarship AwardNo embargoAcademic Major: MathematicsAcademic Major: Classic

Cold War 2.0 or Just Hot Air? Putting U.S.-China AI Competition in Perspective.

The idea of a “Digital Cold War” between the United States and China has taken hold in headlines and policy conversations since 2017, driven by the rapid rise of artificial intelligence. This thesis examines how that analogy gained traction, why it resonates, and whether it holds up under closer scrutiny. It gives particular attention to national security concerns and challenges common assumptions about AI’s future. Drawing from international relations theory, historical analysis, and Cold War scholarship, the project develops a five-part framework based on the defining features of the original Cold War. This framework is then applied to U.S.-China AI rivalry to evaluate the accuracy of the Digital Cold War narrative. Combined with a close analysis of arguments on both sides of the debate, the findings suggest that the parallels to the Cold War are more compelling than the differences. Acknowledging these parallels and reckoning with the power narratives have in shaping policy offers a valuable opportunity to avoid unnecessary escalation and more deliberately shape the trajectory of U.S.-China relations.No embargoAcademic Major: International StudiesAcademic Major: Computer and Information Scienc

The Ohio State University Commencement Address by Charles F. Bolden, Jr., Spring 2025

Commencement address given by Charles F. Bolden, Jr., Former NASA Administrator, Astronaut, and U.S. Marine Major General, to the Spring 2025 graduating class of The Ohio State University, Ohio Stadium, Columbus, Ohio, May 4, 2025

Investigating domain function and protein interactions of the ELMOD family proteins involved in pollen aperture formation in Arabidopsis

In flowering plants, the ancient eukaryotic Engulfment and Motility Domain (ELMOD) genes play a role in the formation of pollen apertures. Apertures are hole-like structures on the pollen surface that develop at distinct plasma membrane domains and lack pollen wall exine. Apertures are conserved within a plant species, yet quite diverse across species. Openings provided by the apertures can allow pollen tubes that carry sperm cells to exit from pollen grains and, in some plant species, loss of apertures leads to male sterility. Two of the Arabidopsis thaliana ELMOD proteins–ELMOD_B (also known as MCR) and ELMOD_A–control the number of apertures while a third protein, ELMOD_E, causes changes in aperture shape when mis-expressed in developing pollen. However, the biochemical function of ELMOD proteins in plants has yet to be deciphered. We have investigated the importance of the ELMOD protein domains by deleting and swapping domains of the ELMOD genes. We demonstrate that 1) all three protein domains in the Arabidopsis ELMODs are essential for these proteins’ function; 2) the C-terminus and the putative GAP region are important for nuclear enrichment; and 3) the N-terminus of ELMOD_E is responsible for its distinct effect on aperture formation while the N-terminus of MCR is important for its function. To identify interactors of the ELMOD proteins, we have also performed protein-protein interaction assays. So far, these assays have discovered weak protein interactions and suggested that plant ELMOD proteins may have biochemical activity different from their mammalian counterparts.Thomas Byers Memorial Scholarship, Ohio State University Department of Molecular GeneticsNSF grant MCB-1817836NSF grant MCB-2240972A five-year embargo was granted for this item.Academic Major: Molecular Genetic

Evaluating the role of sphingolipid signaling in paclitaxel-induced neurotoxicity of SH-SY5Y cells

Chemotherapies like paclitaxel and other similar microtubule targeting agents commonly used in breast cancer treatment can induce sensory peripheral neuropathy in patients, limiting dosage and impacting quality of life. One pathway implicated in chemotherapy induced peripheral neuropathy (CIPN) is sphingolipid signaling. To study the impact of microtubule targeting medications on sphingolipid signaling, SH-SY5Y cells were differentiated into neuron-like cells and treated with different concentrations of paclitaxel, both in the absence and presence of PF543, an inhibitor of sphingosine-kinase 1, the enzyme involved in the production of sphingosine-1-phosphate. Neurite degeneration was assessed using βIII-tubulin staining and high-content imaging. Imaging of paclitaxel-treated SH-SY5Y cells demonstrated neurotoxicity and a reduction in neuronal network complexity. However, PF543 did not exhibit neuroprotective effects under the tested conditions. Future studies may explore optimizing PF543 treatment parameters, such as preincubation, to assess potential protective effects. Additionally, liquid chromatography- mass spectrometry (LC-MS) is being employed to detect levels of ceramide, sphingosine, and sphingosine-1-phosphate. The impact of paclitaxel on sphingolipid signaling is being quantified to evaluate the involvement of this signaling pathway in neurotoxicity.NCI grant R01CA261068Academic Major: Pharmaceutical Science

Impact of Columbus City Health Code 248.05 on Ohio State Students' Smoking Habits

Background: Electronic cigarettes, or e-cigarettes, are devices that can be either disposable or reusable. They use heat to convert liquid into vapor, which is then inhaled to achieve the desired effects. Commonly known as vapes, e-cigarettes typically contain nicotine, an addictive substance, and can also include artificial flavor additives. Young adults are currently the population with the highest rates of e-cigarette use, which is greatly impacted by the availability of desirable flavors such as fruit, mint, and candy. Flavored e-cigarettes account for almost 90% of current adolescent e-cigarette use. Due to their popularity among younger populations, e-cigarettes have become the focus of various federal, state, and local restrictions. This study examines the impact of Columbus City Health Code 248.05, which prohibits the sale of flavored tobacco within city limits, on the smoking habits of Ohio State University (OSU) students. Specifically, it explores how this regulation affects young adults' access to and usage of flavored e-cigarettes, as well as the types of nicotine products they use. Methods: Convenience sampling supplemented by various recruitment strategies to ensure a diverse pool of respondents was used to recruit a sample of twenty-four OSU students who were 21 years and older. Data was collected using a structured Qualtrics questionnaire created specifically for this study which utilizes questions from similar research. The questionnaire included sections on demographic information, e-cigarette preference, other tobacco product usage, access, and use. Results: Data collected showed high rates of awareness of Columbus Health Code 248.05 but low rates of reported expected future impact on e-cigarette use in or around campus. Participants who responded reported age of first tobacco product used or age of initiation between 15-19 years, with flavored e-cigarettes being the most common first tobacco product used. Data showed participants used e-cigarettes ranging from one day a month to daily e-cigarette use. The average participant traveled 6.9 miles to obtain e-cigarettes, but half of the participants who responded reported travelling four miles or less to obtain e-cigarettes; this may suggest that the effects of Columbus Health Code 248.05 can be avoided by driving a short distance away. Of participants who responded, smoke shops and gas/convenience stores were the most popular purchase sites for e-cigarettes, which further underscores the accessibility of these products. The presence of multiple cessation attempts reported prior to and after the Columbus health code suggests the need for smoking cessation supportive measures on campus. Conclusion: This study, which explored the effects of Columbus Health Code 248.05 on Ohio State University’s students’ smoking habits in or around campus, produced information which may be used to inform future research surrounding college student e-cigarette use as well as future cessation programs implemented on college campuses.College of Social WorkNo embargoAcademic Major: Social Wor

Dysregulation of tryptophan biosynthesis as a putative treatment approach for nontypeable Haemophilus influenzae, a causative agent of otitis media

Bacterial adaptation to the nutritional environment of the host is critical for infection. We hypothesize that microevolution due to nutrient stress enhances invasion, intracellular bacterial community formation (IBC), and persistence of nontypeable Haemophilus influenzae (NTHI). We previously identified an NTHI mutant that arose during prolonged nutrient deprivation that promoted in vitro persistence and during experimental otitis media (OM). We determined that a single mutation in the gene encoding cyclic AMP phosphodiesterase reprioritizes NTHI metabolism during biofilm growth in this evolved strain. There was a significant increase in all proteins involved in tryptophan metabolism. Given the importance of tryptophan and tryptophan metabolites in host immunity and bacterial virulence, the contribution of tryptophan biosynthesis on NTHI pathogenesis and intracellular survival was evaluated. We generated a panel of mutant strains impaired in tryptophan biosynthesis, import, or both. Loss of tryptophan synthesis significantly inhibited bacterial growth. We also showed that dysregulation of tryptophan biosynthesis leads to accumulation of the tryptophan metabolite indole which we hypothesize results in indole toxicity of NTHI. We subsequently found that tryptophan biosynthesis pathway impairment significantly inhibited NTHI IBC formation in both human bronchial epithelial cells and in a pre-clinical chinchilla model of OM. When competed against the parent strain, loss of either tryptophan synthesis or import resulted in increased fitness in a chinchilla model. Taken together, NTHI adaptation to nutrient sequestration dysregulates tryptophan biosynthesis and is associated with reduced bacterial viability, possibly through the accumulation of indole. Further, this dysregulation of tryptophan biosynthesis reduces formation of IBCs, which will impact persistence of NTHI. The implications of these discoveries will therefore help guide the future developments of therapeutics for treatment of OM.R21-AI164077 from NIH/NIAID (KMM)A one-year embargo was granted for this item.Academic Major: Biomedical Scienc

Tracking Urbanization's Impact on Bird Functional Diversity Over Time

Introduction: Urbanization drives major changes in the natural environment and its role in bird diversity decline has been the focus of extensive research. Most studies assess the effects of anthropogenic stressors on biodiversity using a space-for-time substitution, examining urbanization levels across a gradient from rural to highly urbanized environments. In contrast, this study investigates how different levels of urbanization change affect bird diversity through time. My goal is to determine whether a temporal approach yields results similar to or different from those found in space-for-time substitution studies. Methods: The study region includes Indiana, Ohio, and Kentucky, encompassing the metropolitan areas of Indianapolis, Columbus, Cincinnati, and Louisville. Using eBird data, I first developed Species Distribution Models (SDM) to generate predictions of bird presences and absences for 134 species in two time periods: 2013 and 2023. Using these predictions, I then assessed bird diversity using four metrics: species richness, functional richness, functional evenness, and functional divergence. The latter three metrics were derived by analyzing the trait space, an n-dimensional representation of species' traits that influence how species interact with and shape their environment. All avian diversity metrics were obtained for each year for each 3kmx3km site across the study region. I used NLCD impervious surface data to quantify change in urbanization. Change in avian diversity was then modeled as a function of change in impervious surfaces. Results: Model results indicated that functional richness decreases with increasing levels of urbanization. Specifically, sites with medium and high levels of urbanization change saw the most dramatic declines in avian functional diversity. In contrast, I found that increasing urbanization led to increases in species richness. Specifically, sites characterized by medium change in urbanization have seen larger increases in species richness compared to sites characterized by no change, low change, or high change in urbanization. Finally, sites with high levels of urbanization had an increase in functional evenness and functional divergence compared to sites with no change in urbanization. Conclusions: Findings of declining functional richness and increasing species richness with increasing temporal change in urbanization corroborate findings from previous space-for-time substitution studies that focused on spatial urban gradients. These replicated patterns provide justification for using the space-for-time substitution as a proxy for temporal change in urban development and thus for assessing the effects of urbanization on avian diversity change. By reinforcing the findings of previous studies, my work broadens our understanding of urbanization’s impact on biodiversity and provides a blueprint for urban developers and conservation managers to ensure that adequate habitat for birds is preserved during urban development.No embargoAcademic Major: Data Analytic

Investigating Wash Off of Fines from Aggregate Used in Permeable Pavement Construction: Implications for Long-Term Function

Permeable pavements are a widely implemented green infrastructure (GI) practice used to reduce urban runoff and filter pollutants. While research has shown permeable pavements improve water quality, little attention has been given to the effects of construction materials used in these systems and their effects on effluent quality. A few studies have noted potential sediment wash off from aggregates immediately following construction (i.e., a start-up effect), which this study assessed using a controlled laboratory study with 12 PVC columns. Each column contained layered limestone aggregate and a concrete paver to model typical permeable interlocking concrete pavement (PICP) systems, one type of permeable pavement. Four treatments were evaluated in triplicate: two flow rates (high [37.85 liters per hour] and low [3.785 liters per hour]) and aggregate sourced from two different quarries. Effluent from simulated storm events was analyzed for total suspended solids (TSS) and particle size distribution (PSD). For the first simulated storm event, effluent TSS concentrations ranged from 941.43-2402.94 mg/L. A sharp decline in effluent TSS was observed within the first 6 storm events for every treatment, with initial decay trending toward a final horizontal asymptote for TSS concentrations. After nearly the equivalent of one year of rainfall, TSS concentrations in three of the four treatments remained above the average PICP effluent concentration of 22 mg/L from a database of field studies of permeable pavements, suggesting extensive, continued sediment wash-off. PSD did not change significantly over time and exhibited few differences across treatments. These findings underscore the importance of refining aggregate preparation techniques to reduce sediment wash off following permeable pavement construction, thereby reducing effluent TSS concentrations, limiting clogging at the underlying soil interface, and improving long-term infiltration capacity. This research provides valuable insights to optimizing PICP design and construction practices for urban stormwater management.A one-year embargo was granted for this item.Academic Major: Environmental Scienc