Life Sciences Commons^™

A Tractable Nematode Model For The Emerging Fungal Pathogen, Candida Auris, Melissa Martinez

Dissertations and Theses (Open Access)

Candida auris is an emerging multidrug-resistant opportunistic fungal pathogen. It

poses a significant threat to immunocompromised patients and those with prolonged stays in

healthcare facilities. C. auris spreads rapidly in health care facilities through enhanced

colonization of skin and abiotic surfaces. The genetic factors contributing to this ability and to

the virulence, drug resistance, and stress-tolerant nature of C. auris are largely unknown.

Current animal models of C. auris infections are not well standardized and report conflicting

results. Additional animal models of virulence are needed, especially those amenable to high-

throughput analysis. The nematode Caenorhabditis elegans has been validated as …

Targeting Breast Cancer Brain Metastasis Through Novel Combination Of Fda-Approved Orally Active Blood-Brain Barrier Permeable Ret And Tgli1 Inhibitors, Joshua Cha

Dissertations and Theses (Open Access)

Breast cancer is the most diagnosed cancer in American women, and breast cancer brain metastasis (BCBM) exhibits the worst prognoses with a life-expectancy averaging at 6 months. This short life expectancy is largely attributed to the lack of effective treatment. Many challenges remain unsolved, including the limited number of actionable targets for targeted therapy and effective blood-brain barrier (BBB) permeable drugs that are safe without promoting drug resistance. Therefore, there is an urgent call for identification of novel therapeutic targets and development of BBB-permeable drugs. One of the potential targets identified by our lab for BCBM targeted therapy is the …

Pattern Dynamics And Stochasticity Of Brain Rhythms And Spike Trains In A Tauopathy Mouse Model Of Alzheimer’S Disease, Clarissa M. Hoffman

Dissertations and Theses (Open Access)

Systems neuroscience posits that every aspect of perceived physical reality, every aspect of animal and human behavior, and every cognitive phenomenon emerges from patterns of neuronal activity. While most researchers embrace this idea, there are major difficulties in describing and analyzing these complex neuronal dynamics—spike flows produced by cells ensembles, synchronized extracellular field oscillations, and other patterns—which limits our understanding of how the activity of individual neurons and the whole-animal cognition and behavior might be connected. In particular, we lack the approaches and even the semantics for connecting the individual cell outputs and the integrated results of their activity. Current …

Characterization Of Staphylococcus Aureus Clinical Isolates From Deep Musculoskeletal Infections For An In Vitro Biofilm Model For Phage Therapy, Raquel C. Luna

Dissertations and Theses (Open Access)

The rise of multidrug-resistant (MDR) infections is a growing concern in the treatment of deep musculoskeletal infections (MSKIs) and orthopaedic device-related infections (ODRIs). Staphylococcus aureus is responsible for about one third of these infections due to its strong biofilm forming capacity, presence on human skin, and the large number of antibiotic-resistant variants. Bacteriophage (phage) therapy is now being considered as a treatment for MDR MSKIs/ODRIs. We are investigating the use of phage encapsulated into or adsorbed onto biodegradable microspheres for local delivery to the site of these MDR infections. We determined that the anti-staphylococcal phage K effectively lyses the S. …

From Antigen Presentation To Tumor Control: Mechanisms Of Type I Conventional Dendritic Cell-Based Cancer Vaccines, Josue E. Pineda

Dissertations and Theses (Open Access)

Type 1 conventional dendritic cells (cDC1s) are important for generating and sustaining antitumor immunity. Accordingly, the abundance of cDC1s in human tumors correlates with improved outcomes in cancer. Capitalizing on this role, we previously demonstrated that vaccination with in vitro-derived murine cDC1s elicits durable tumor control in multiple preclinical models; however, the immunological mechanisms underlying the efficacy of cDC1 vaccination remain unclear. Here, we examined whether in vitro-derived cDC1s resemble tumor-infiltrating DC populations and whether MHC-I and MHC-II antigen presentation contribute to cDC1-mediated tumor control following vaccination in melanoma.

As expected, MHC-I- or MHC-II-deficiency had minimal impact on …

Membrane Organization Of Rheb And Rhoa: Roles In Function And Allosteric Druggability, Chase M. Hutchins

Dissertations and Theses (Open Access)

Small GTPases of the Ras superfamily are membrane-bound molecular switches that regulate nearly all major cellular processes, and their dysregulation drives cancers, neurological disorders, and metabolic diseases. While anchored to cellular membranes, the catalytic domains of small GTPases undergo orientation dynamics, adopting distinct configurations that can occlude or expose effector-binding surfaces and modulate signaling output. These dynamics have been characterized in the Ras oncoproteins, but whether they extend across the superfamily and influence allosteric druggability has remained unknown.

In this dissertation, I address these questions through Rheb and RhoA, two small GTPases with complementary differences in subfamily lineage, membrane localization, …

Platelet Gαz Regulates Ovarian Tumor Growth And Mediates The Effects Of Chronic Stress, María G. Torres Carrizalez

Dissertations and Theses (Open Access)

Ovarian cancer is the most aggressive gynecologic cancer, with 12,450 estimated deaths in 2026. Elevated platelet counts are commonly observed in patients with ovarian cancer and are associated with enhanced tumor growth and poor prognosis. Patients with ovarian cancer are frequently exposed to elevated levels of stress, which has been correlated with accelerated disease progression and increased mortality. Interestingly, the platelet Gαz protein is activated by epinephrine through the α2A-adrenergic receptor, suggesting a potential mechanistic link between stress signaling and platelet-driven tumor progression. To investigate this, I evaluated the role of platelet Gαz in ovarian cancer using control (Gz^{fl/fl …}

Understanding Epigenomic Landscapes In Cancer Progression And Immunotherapy Response, Jonathan Schulz

Dissertations and Theses (Open Access)

Nonmutational epigenomic reprogramming has emerged as a key hallmark of cancer that plays crucial roles in tumor evolution during its progression and response to therapy. However, the extent and nature of epigenomic reprogramming remains poorly understood. This dissertation examines how epigenetic regulation shapes cancer progression and response to immunotherapy. Working at the intersection of cancer biology and computational genomics, it develops analytical frameworks for characterizing chromatin structure and DNA methylation across diverse tumor contexts and uses these frameworks to address two complementary biological questions: how promoter-associated chromatin organization varies across cancer types, and how epigenetic perturbation modulates tumor immunogenicity in …

Refining Treatment Thresholds Of Insect Pests In South Carolina Soybeans Using Simulated Injury And Natural Populations, Adam Whitfield

All Dissertations

Insect pests are a major limiting factor to profitable soybean, Glycine max (L.) Merr., production in South Carolina, yet current economic thresholds are largely based on historical data and may not reflect modern cultivars, production practices, or input costs. Key insect pests in South Carolina can be categorized into three major feeding groups: defoliators, stem feeders, and pod feeders. Defoliating insects include, but are not limited to, soybean looper, Chrysodeixis includens (Walker); velvetbean caterpillar, Anticarsia gemmatalis (Hubner); green cloverworm, Hypena scabra (Fabricius); grasshoppers; and numerous species of beetles. Stem feeders include, but are not limited to, kudzu bug, Megacopta cribraria …

Abnormal Trafficking And Processing Of Multiple Matrix Metalloproteinases Drive Cartilage Defects In Congenital Disorders Of Glycosylation, Chia-Lun Wu

All Dissertations

Congenital Disorders of Glycosylation (CDG) are rare metabolic diseases caused by defects in glycosylation. Despite identification of over 200 CDG types, the mechanisms linking glycosylation defects to diverse clinical phenotypes remain unclear. This dissertation uses zebrafish models of PMM2-CDG and STT3-CDG to redefine CDG pathogenesis, shifting from a simple glycan deficiency model to one involving disrupted cellular spatial organization.

We identify a protease-dependent pathway underlying craniofacial cartilage defects. Specifically, defective proteolytic processing of N-cadherin, a key adhesion molecule in chondrogenesis, is a central driver of pathology. We further uncover an unconventional trafficking mechanism in which ER stress and altered secretory …

The Impact Of Label Material On Perceived Value And Environmental-Friendliness Of Beverages In Returnable Glass Bottles Versus Actual Environmental Impact Via Life Cycle Assessment, Toni Sharp

All Dissertations

With guidance from the EPA to reduce virgin packaging use and alternatively increase reuse, the concept of reusable packaging has re-emerged as a potential sustainable alternative to single-use and recyclable packaging. For businesses, an understanding of the potential environmental benefits of switching from single-use packaging to reusable packaging, along with consumer willingness to pay for sustainable packaging are paramount. Existing literature on willingness to pay (WTP) for ethical or sustainable products typically relies on consumers’ stated preferences found through surveys using hypothetical products and prices. It has been revealed that sustainability claims printed on the label or products in glass …

Diffuse Radiation Controls On Southern Pine Forest Ecosystem Functioning, Jeremy Forsythe

All Dissertations

Diffuse solar radiation, sunlight scattered by atmospheric aerosols and/or clouds, enhances plant photosynthesis through the diffuse fertilization effect (DFE), increasing ecosystem gross primary productivity (GPP) per unit of incoming radiation. Despite this known effect, pine forests of the southeastern United States remain comparatively understudied in the diffuse light literature. This is a critical knowledge gap, as the southeastern United States sequesters more carbon than any other region of the conterminous country (approximately 176 ± 26 Tg C yr⁻¹, or roughly 56% of national forest net carbon exchange), and the region experiences some of the highest biogenic aerosol loads in North …

Neurobiological Mechanisms Of Attention In Adolescents, Virginia Clark

All Dissertations

Adolescence is a transformative developmental period characterized by profound biological, neurological, and behavioral changes. This dissertation investigates the neurobiological underpinnings of attention in adolescents, emphasizing how internal mechanisms influence and individually shape cognitive development through the endosystem. Rooted in the intersection of human development, learning sciences, and cognitive neuroscience, this work argues for a more integrated understanding of attention as a fundamental cognitive function for learning, one that is behaviorally seen but also biologically and neurologically driven. While developmental science has often emphasized external influences such as family, culture, and environment, this work centers on the adolescent’s internal biological systems …

Feeding Ecology In Coastal Systems, Randi L. Cannon

Graduate Theses and Dissertations (2019 - present)

Oysters (Crassostrea virginica) are critical foundation species in estuaries, providing numerous ecological and economic benefits. However, oyster populations have diminished worldwide. Effective oyster restoration and aquaculture require a mechanistic understanding of the physiological and environmental factors that govern oyster feeding, growth, and resilience under changing coastal conditions. We investigated how oyster ploidy and environmental conditions influenced oyster feeding and investigated how changes in abiotic conditions affected behavioral performance of oyster drills (Stramonita spp.), a key oyster predator. To better understand feeding responses and behaviors of both predator and prey we 1) used in-situ filter feeding assays to determine if feeding …

A Novel Method Of Protein Purification Using Hedgehog Proteins As An Inducible, Self-Cleaving Tag, Antonia Kladias

Undergraduate Honors Theses

Because removing extraneous purification tag sequences from native proteins can be challenging and costly, there is demand for simple all-in-one techniques that directly furnish a tagless, functional protein-of-interest (POI). Current tagless purification systems are based on intein biochemistry; however, intein-based purification requires expensive, specialized resins and the POI often must be fused to the intein’s C-terminus. In this thesis, I present a novel approach for tagless POI purification in which the Drosophila melanogaster hedgehog protein catalytic domain (HhC) is repurposed as a small-molecule inducible, self-cleaving element dubbed Gtag. With Gtag, the POI is fused to the N-terminus of HhC/Gtag with …

Assessing The Use Of Exon-Skipping Morpholino Antisense Oligonucleotides Targeting The Different Sumo Paralogs As Enhancers Of The Antitumor Activity Of Chemotherapeutic Agents, Andrea Teresa Garcia-Morin

Open Access Theses & Dissertations

Post-translational modifications (PTMs) are critical regulators of protein function, stability, and localization, with SUMOylation emerging as a key modulator of cellular stress response and survival in cancer. Non-small cell lung cancer (NSCLC) is characterized by heightened dependence on SUMOylation to sustain pro-survival signaling, DNA repair, and resistance to chemotherapy. This dissertation investigates a novel chemosensitization strategy based on the splice-switching of SUMO transcripts in NSCLC cells using exon-skipping morpholinos (ESMs), which redirect splicing toward non-conjugatable SUMO alpha isoforms, thereby reducing global SUMOylation. We hypothesized that decreasing global SUMOylation through forced alternative splicing of SUMO transcripts would impair the stress-protective functions …

Application Of Path Analysis To Determine The Impact Of Age And Sex On The Neural Circuits That Promote Nicotine Withdrawal Severity, Veronika Espinoza

Open Access Theses & Dissertations

The rising prevalence of electronic cigarette (e-cigarette) use presents a major public health concern, particularly in adolescent females who are most susceptible to nicotine use and its long-term negative health consequences. The goal of this dissertation was to utilize preclinical rodent models to understand how group differences in age and sex influence neural activation patterns in brain circuits believed to promote nicotine withdrawal. Prior pre-clinical work, conducted largely in male rodents, has established that there are two major brain pathways that modulate the behavioral effects of nicotine withdrawal. These include the mesolimbic and medial habenula-interpeduncular nucleus (MHb-IPN) pathways. To assess …

Novel Roles Of G-Beta-Gamma Signaling In Microtubule Dynamics And Neurodegeneration, Diana I. Olivas

Open Access Theses & Dissertations

Neurodegenerative disorders (NDDs), including Alzheimer's disease (AD), are characterized by progressive neuronal dysfunction, cytoskeletal disruption, and cognitive decline. Although Tau hyperphosphorylation and neurofibrillary tangle (NFT) formation are classical hallmarks of AD, emerging evidence suggests that microtubule (MT) dysfunction may precede and occur independently of Tau pathology. Understanding upstream regulators of MT dynamics is therefore critical for elucidating early mechanisms of neurodegeneration. Previous work from our laboratory demonstrated that G protein βγ (Gβγ) subunits directly interact with tubulin and promote MT assembly. However, the mechanism of Gβγ signaling in neuronal cytoskeletal stability and neurodegeneration remained poorly understood. The present study investigated …

Drug Repurposing Against Giardia Targeting Lipid Rafts, Extracellular Vesicles, And Sphingolipid Synthesis, Breanna Chantal Pence

Open Access Theses & Dissertations

Giardia lamblia is a protozoan parasite responsible for the intestinal disease giardiasis worldwide. Giardia is one of the major intestinal parasites in the world, with over 500,000 new cases annually. Symptoms of giardiasis include diarrhea, abdominal pain, and nausea. Children are particularly vulnerable to giardiasis, with cases of malnutrition, stunted growth, and cognitive impairment in countries where the disease is endemic. Giardia consists of two morphologic forms: an infective cyst which transmits the disease and a motile trophozoite which attaches to the epithelium of the small intestine during infection. Metronidazole is a common treatment for giardiasis, but cases of toxicity …

Metabolomics In The Dryland Critical Zone: The Role Of Soil Metabolites In Phosphorus Acquisition, Kalpana Kukreja

Open Access Theses & Dissertations

Earth's Critical Zone (CZ) plays a key role in sustaining life through carbon, water, and nutrient cycling from the top of the canopy to the groundwater. A key feature of critical zone research is the integration of multiple interdisciplinary techniques. An emerging set of techniques that can add to this approach is the field of metabolomics, the quantification and study of comprehensive metabolite profiles. In this dissertation, I apply metabolomics to address knowledge gaps in dryland critical zone ecosystems, specifically how soil metabolite dynamics influence biogeochemical processes, and with a particular emphasis on phosphorus (P) cycling in the Chihuahuan Desert. …

Plant Communities Of Arid Ephemeral Stream Streams, Biogeographic Filters, Climatic Sensitivity, Urban Impacts Across Spatial And Temporal Scales, Luis Miranda

Open Access Theses & Dissertations

Ephemeral stream networks, locally known as arroyos, are among the most ecologically significant yet least protected habitats in arid landscapes. Despite supporting a disproportionately high plant biodiversity compared to surrounding uplands, these riparian systems lack regulatory protection in most arid U.S. states and face increasing pressure from urban expansion and intensifying climate change. There is an urgent need to understand how these factors influence riparian plant communities and hinder their ability to recover, enabling effective conservation and management strategies. In this dissertation, I explored the interplay of biogeographic gradients, precipitation variability, and urbanization in shaping arroyo riparian plant communities across …

Salience Network Circuit Dynamics In Distress Tolerance And Drug-Seeking Vulnerability, Marina Alicia Smoak

Open Access Theses & Dissertations

The psychological distress experienced during drug withdrawal can lead individuals with substance use disorder to abandon their goal of abstinence. Numerous human studies demonstrate that an inability to persist in challenging, goal-directed behavior while experiencing psychological distress is associated with multiple stages of substance use, including relapse. This behavioral construct is referred to as low distress tolerance (DT). Rodent models of DT similarly show that low DT predicts elevated cocaine relapse, particularly when DT is assessed following extended abstinence. This abstinence period corresponds with the incubation of craving, a phenomenon characterized by progressively increased cocaine-seeking over time. Importantly, relapse vulnerability …

Characterization Of The Antiviral Activity Of Mouse Schlafen Proteins, Wendy Paola Alvarez Leal

Open Access Theses & Dissertations

The goal of this work was to characterize the anti-viral role of mouse Schlafen8 and Schlafen9. Expression of these proteins is induced by type I interferon in response to viral infections. Importantly, their human functional orthologs exhibit anti-viral functions, and the structural element required for these activities are conserved in Schlafen8 and Schlafen9. Therefore, it is expected that these proteins will also impair viral replication. An important limitation in this field is that the anti-viral function of human SLFNs has been evidenced only in in vitro cellular models. No informative mutations have been described in human populations so far. Thus, …

Enhancing Walleye (Ogaa) Recruitment: Evaluating Assisted Reproduction As A Mitigation Strategy, Douglass Keiser

Biology Graduate Theses

Over the past several decades, cold- and cool-water fish populations across the Upper Midwest, including Minnesota and Wisconsin, have shown troubling signs of decline. Among the most affected is the walleye/Ogaa (Sander vitreus), a species deeply embedded in the ecological balance, cultural identity, and economic vitality of the region, and central to the lifeways, treaty-reserved rights, and resource stewardship of Tribal Nations, including Ojibwe communities across the Upper Midwest. Despite ongoing stocking efforts and harvest regulations, many lake systems have experienced persistent declines in natural recruitment, prompting resource agencies to investigate the underlying causes. One such system is …

Degradation And Metabolic Analysis Of Synthesized Quorum-Sensing Signals By The Model Eukaryote Chlamydomonas Reinhardtii, Adam Josef Bach

Theses and Dissertations

Bacterial organisms can “talk” with one another on a colony-wide scale using a communication system known as quorum-sensing (QS) via chemical signals. These signals are produced at a basal rate throughout the life of the bacteria and are classified as autoinducers, which diffuse across the cell membrane. Once the critical concentration is reached, they begin to diffuse back into the cell and initiate a phenotypic change. As these signals exist outside the membrane of their producer, they are also accessible to other organisms. It has already been noted that some plant species uptake these compounds through their roots and break …

Intraday Cotton Futures Price Responses To World Agricultural Supply And Demand Estimates (Wasde) News, Owen Mclane Tyrone

Graduate Theses and Dissertations

Price discovery in agricultural futures markets is augmented by information about supply and demand, leading markets to react when public reports are released. Effective price discovery in futures markets is vital to allocate physical commodities across time, synthesize information, and provide hedging tools. Price discovery in cotton markets is unique because it is less liquid than many other commodity markets. Therefore, our objective is to measure the initial price response in the cotton futures market to unanticipated ending stocks information in the WASDE report; then determine if markets continue to adjust after the initial price change. To meet our objective, …

Nadh Flim Reveals Cellular Bioenergetics And Mitochondrial Morphology During Drosophila Convergent Extension, Maria Espana Pena

Graduate Theses and Dissertations

Mitochondria are dynamic organelles that can fragment or fuse to support different bioenergetic demands and cellular processes, although the role of mitochondrial fission and fusion during embryonic development is not well understood. Fluorescence lifetime imaging (FLIM) of the mitochondrial cofactor NADH can be used to visualize mitochondrial networks and infer aspects of cellular bioenergetics in a label-free manner. We used NADH FLIM to test whether germband cells undergo changes in cellular metabolism during Drosophila convergent extension (CE)––a process in which hundreds of epithelial cells undergo coordinated intercalation to elongate the embryo. Contrary to our expectations, we did not observe significant …

Exploring Agricultural Pathways: An Analysis Of Arkansas Community Colleges, Natasha Hightower

Graduate Theses and Dissertations

As demand for a highly skilled agricultural workforce continues to grow, Arkansas must strengthen accessible and clearly defined academic and career pathways to prepare future agricultural professionals. Community colleges serve as a critical entry point into higher education, particularly for rural and first-generation students, and play a vital role in both workforce development and transfer preparation. However, information related to agricultural education offerings, transfer pathways, and faculty at Arkansas community colleges is often decentralized and difficult for students and stakeholders to locate. The purpose of this study was to examine agricultural education offerings at community colleges in Arkansas, specifically agricultural …

Genomic Surveillance Of Guillain–Barré Syndrome-Associated Genes In Campylobacter Jejuni Across Human And Non-Human Reservoirs, Emma Doughty

Biological Sciences

Campylobacter jejuni is a leading cause of foodborne illness and a major trigger of Guillain–Barré Syndrome (GBS), an autoimmune neuropathy caused by molecular mimicry between bacterial lipooligosaccharides (LOS) and host nerve gangliosides. While prior genomic studies have focused primarily on human clinical isolates, the prevalence and distribution of GBS-associated genes in non-human reservoirs remain poorly characterized. This study used genomic datasets derived from analyses of human and non-human C. jejuni isolates to assess the distribution of GBS-associated genes, with a focus on the neuABC sialylation pathway. Results demonstrate that these genes are present in both host types, across multiple geographic …

Alternative Abl1 Isoform Expression In Oncogenic Translocations: Implications For Cancer Progression, Jessica Teague

Biological Sciences

Abstract (also on poster): Previous studies in our lab show that an alternate isoform of Bruton’s tyrosine kinase, BTK-C, is required for the survival of several epithelial-derived cancer cells. BTK-C is transcribed from an alternative promoter and includes a 34-amino-acid N- terminal extension with a palmitoylation sequence that alters its subcellular localization. Nine other human kinases have similar alternative N-termini (ANT), often producing palmitoylated or non-palmitoylated isoforms from different transcriptional start sites. Among these, ABL1 is a known oncogenic kinase and key drug target. Translocation mutations at the 5′ end of ABL1 are a major cause of adult leukemias. This …