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Exploring The Antagonistic Polymicrobial Interaction Of Alcaligenes Faecalis With Prokaryotic And Eukaryotic Microorganisms, Aly Hargrave

Electronic Theses and Dissertations

Alcaligenes faecalis, a generally nonpathogenic, Gram-negative bacterium, has been observed by our laboratory to possess antagonistic activity against antimicrobial-resistant genera Staphylococcus, Candida, and Bacillus. This study focused on exploring the inhibition mechanism of A. faecalis against the three genera, with an emphasis on S. aureus. A library of A. faecalis transposon mutants was constructed and identified fourteen possible genetic factors linked to this inhibitory activity. Characterization of this inhibition indicated that A. faecalis suppressed S. aureus planktonic and biofilm growth via a contact-dependent mechanism, with pronounced effects during biofilm attachment phase. In a Caenorhabditis elegans …

Impact Of Shear Flow On Marine Biofilms Using Hyperspectral Imaging, Shantanu Mahesh Kore

All Theses

Various microbial communities in marine biofilms cause biofouling on submerged surfaces, posing challenges to marine industries. Despite their ecological and economic importance, biofilms' biomechanical and biochemical responses to hydrodynamic shear stress are insufficiently understood, particularly in dynamic flow conditions. To fill this gap, our study uses an innovative fiber-optic hyperspectral imaging (HSI) system and a supercontinuum laser source to examine marine biofilms' structure, composition, and detachment behavior at different shear stress levels.

To detect spectral and spatial heterogeneity in live biofilms without labeling, we created a custom imaging pipeline that captures reflectance spectra in the 600-850 nm range, targeting microbial …

Thymosin Beta-4: A Novel Treatment For Acanthamoeba Keratitis, Victoria A. Murphey

All Theses

Acanthamoeba keratitis (AK) is a severe corneal infection caused by the free-living amoeba, Acanthamoeba. Both stages of its life cycle (trophozoite and cyst) cause infection, primarily in contact lens wearers. It is often misdiagnosed, leading to delayed treatment and poor clinical outcomes. Current treatment options for AK rely on anti-amoebic agents that are toxic to corneal epithelial cells. Further, no single drug can eliminate both forms of the amoeba. Approximately 30% of all AK infections require a corneal transplant.

Thymosin beta-4 (Tβ4) is a G-actin binding protein synthesized in almost all human cells, including corneal epithelial cells. Tβ4 exhibits …

African Sleeping Sickness: From Basic Biology To Future Directions, Riddhi R. Patel

All Theses

African Sleeping Sickness is a Neglected Tropical Disease (NTD) which poses a significant health risk to impoverished populations in 36 Sub-Saharan African countries. It is a devastating disease caused by the protozoan parasite Trypanosoma brucei, which is transmitted to mammals via the bite of infected tsetse flies. The disease manifests in two stages: the hemolymphatic stage and the meningoencephalitic stage. In the latter stage, it invades the Central Nervous System (CNS) and can be fatal if left untreated. It is caused by morphologically indistinguishable species of Trypanosoma brucei in both humans and animals, where in humans it is known as …

Anaerobic Soil Disinfestation As A Non-Chemical Management Option Against Fungi And Heterotrophic Bacteria In Organic Sweetpotato Production, Meredith Tucker

All Theses

North Carolina is the largest producer of sweetpotatoes in the United States, with South Carolina increasing farming acreage to 2,501 in 2022 compared to 1,300 in 2017. Growers producing conventional and organic sweetpotatoes are equally challenged with managing fungal pathogens due to fungicide resistance or fungicides being unavailable due to environmental regulations, leading many to shift to growing organic crops. Anaerobic soil disinfestation (ASD) is a non-chemical pre-plant management option that uses a carbon amendment, irrigation, and plasticulture to establish an anaerobic environment in soils, killing soil microbes. A greenhouse study was conducted to assess ASD on fungal pathogens and …

Chromosome Evolution Model Reveals Hidden Variation In Karyotype-Driven Speciation In Ferns, Thomas Buchloh

All Theses

Because karyotype change commonly generates reproductive isolation between diverging species, rapid karyotype evolution, like that seen in plants, may increase the total rate of diversification. However, few studies have investigated this predicted relationship. Tests of this prediction have identified a positive correlation between the rate of karyotype change (specifically whole genome duplications) and diversification, but tests have been restricted to relatively small and young clades. Fortunately, novel macroevolutionary models have recently become available to investigate patterns of karyotype evolution in large phylogenies, providing new opportunity to investigate variation in karyotype driven diversification. Ferns are one of the most karyotype rich …

Impact Of Temperature And Microbial Infection On The Honey Bee Hemocytes, Michael E. Oeth

Master's Theses

Introduction

Honey bees (Apis mellifera) rely on hemocytes for immunity, wound healing, and hemolymph homeostasis. While 32°C reflects optimal hive conditions, suboptimal temperatures (22°C) and stressors like pathogens (Varroa destructor, bacteria) or pesticides impair hemocyte function. Using clodronate liposomes (CLD) to deplete hemocytes, we assessed how immune suppression interacts with these stressors.

Methods

Newly emerged (5-day-old) and older (15-day-old) bees were assigned to: CLD, control liposomes (LP), PBS, injection wound, or no treatment. Cohorts were exposed to 32°C (optimal) or 22°C (stressful for non-immunosuppressed bees). Fifteen-day-old bees were challenged with Escherichia coli or Staphylococcus aureus. Survival, hemolymph volume, and hemocyte …

Population Estimates, Demography, And Habitat Assessment Of The Pearl River Map Turtle (Graptemys Pearlensis) In The Pearl River Drainage Of Mississippi, Noah Devros

Master's Theses

The Pearl River map turtle (Graptemys pearlensis) is a highly riverine Emydid endemic to the Pearl River drainage of central and southern Mississippi and southern Louisiana. First described in 2010, G. pearlensis was listed as federally Threatened in 2024. . Due to its relative novelty as a species, no rigorous site-specific population estimates of G. pearlensis in Mississippi have been conducted. The primary goal of this study was to implement a replicable method of assessing the population of G. pearlensis throughout the Pearl River drainage system of Mississippi. A secondary goal was to describe habitat associated with G. …

Movement Ecology And Trophic Dynamics In The Northern Gulf Of Mexico: Implications For Fisheries Management, Calvin Chee

Master's Theses

The northern Gulf of Mexico (nGOM) is a diverse and productive region for living marine resources. The region supports lucrative commercial and recreational fisheries ranging from low-trophic-level species, such as penaeid shrimps and forage fishes, to high-trophic-level predators (e.g. Yellowfin Tuna). This thesis contributes to the region’s ecological knowledge, with the primary aim of enhancing management efforts and providing direct management advice to two important fisheries. In Chapter 1, we develop a traditional per-recruit model for Southern Flounder, as well as a spatiotemporally integrated per-recruit model that incorporates the spatial distribution of fishing effort and the stock’s movement ecology. Fish …

The Impact Of Emdr Therapy On Past Suicidal Ideation: Lived Experiences Of Young Adults, Lindsey Faehnrich

Undergraduate Honors Theses

This study explores the effectiveness of Eye Movement Desensitization and Reprocessing (EMDR) therapy in reducing suicidal ideation and improving mental health outcomes among college-attending young adults (ages 18–24) with a history of trauma. EMDR is a body-based psychotherapy designed to alleviate distressing thoughts and trauma. It gained attention for its positive impact on PTSD and has more recently been applied to other mental health disorders. The literature review highlights risk factors including trauma, mental health disorders, suicidal ideation, and EMDR. The methods detail a phenomenological approach, interviewing four young adults who underwent EMDR and experienced past suicidal ideation. This provided …

Whole-Genome Assembly And Annotation Of The Firecracker Penstemon (Penstemon Eatonii), David E. Jarvis, Mikel R. Stevens, Payton Carter, Ying Fei Lin, Kate E. Jaggi, Gabriela Jijon, Teal Kalt, Jouber Calixto, Samantha Standring, Kaitlin Torres, Kayla B. Stephensen, Hayley Mangelson, Noah H. Williams, Carolyn A. Wessinger, Peter J. Maughan, Paul B. Frandsen

Faculty Publications

The penstemons are ornamental annual flowering plants native to the Intermountain West and Rocky Mountains and commonly used for urban landscaping. Elite commercial penstemons are generally susceptible to abiotic stresses, including drought, root rot, cold, and high salinity. Firecracker penstemon (Penstemon eatonii), however, is much more tolerant to these stresses than most elite cultivars. Importantly, firecracker penstemon has been reported to hybridize with many other penstemons and therefore provides the opportunity to develop more tolerant elite cultivars through strategic crossing. To facilitate the study and utilization of firecracker penstemon, we sequenced and annotated the genome of a P. …

Population Dynamics, Life History Characteristics, And Environmental Drivers Of Neomysis Americana In The Damariscotta River Estuary, Allison Fogg Ms '25

All Student Scholarship

Mysid shrimp (Neomysis americana) play a pivotal role in estuarine food webs by linking primary producers to higher trophic levels and serving as an important food source for commercially valuable fish. Despite their ecological significance, mysids are often under sampled, leading to gaps in our understanding of their population dynamics and life history traits. My study investigated N. americana over a full year (June 2023 to May 2024) in the temperate Damariscotta River Estuary in Maine. My research focused on how environmental factors such as temperature, turbidity, salinity, chlorophyll-a, and zooplankton biomass affect mysid density and reproduction. Temperature emerged as …

Therapeutic Vulnerabilities Of Venetoclax Resistant Chronic Lymphocytic Leukemia And Novel Treatment Strategies Targeting Bcl2/Bcl-Xl, Daisy Y. Diaz-Rohena

Dissertations and Theses (Open Access)

Despite major advancements in the management of chronic lymphocytic leukemia (CLL), drug resistance remains a major challenge. CLL resistant to venetoclax (VEN) have limited available therapeutic options, especially when the leukemic cells have dysfunctional p53 and have relapsed on Bruton’s tyrosine kinase inhibitors (BTKi). The broad hypothesis of this thesis is that VEN-relapsed CLL exhibits altered dependence on BCL2 family members, which can be exploited for therapeutic benefit. I profiled 28 CLL samples collected from 15 patients either at baseline or at relapse following VEN treatment, which was administered in combination with a BTKi or sequentially as monotherapy after a …

Ascl2 Positive Tumor Cells Modulate The Response Of Metastatic Colorectal Cancer To Mapk-Targeting Therapy, Oscar Eduardo Villarreal

Dissertations and Theses (Open Access)

Colorectal cancer (CRC) is the second leading cause of cancer related deaths with nearly a quarter of patients presenting with metastatic disease at the time of their diagnosis. Therapeutic management of metastatic CRC continues to be a major challenge due to therapy resistance and disease heterogeneity. Due to its central role in tumorigenesis, CRC is commonly treated with MAPK pathway inhibitors (MAPKi). However, clinical trials repeatedly demonstrates that durability of benefit is short-lived in many patients. While genomic mechanisms of acquired resistance have been described, they explain a minority of patients, and further research is needed to determine the underlying …

Emotional Outbursts In Latinx Autistic Youth With Intact Or Non-Intact Families; Frequency, Severity, And Socio-Demographic Correlates, Sandra Lucia Masso Hernandez

Theses and Dissertations

Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder characterized by impaired social interaction, communication, and restricted repetitive behaviors. One of the core difficulties in individuals with ASD is related to emotional outbursts. Emotional outbursts (EO) are behavioral episodes in response to situations, environmental and physiological stimuli that occur in an extreme, unpleasant, sometimes aggressive way, often disproportionate to the context. Considering the impacts that EO’s can cause in populations with neurodevelopmental disorders and on the well-being and mental health of parents/caregivers, the need arises to evaluate these populations. Due to the core characteristics of ASD (such as a rigid mentality, …

Patterns Of Fire History And Vegetation Changes In The Last 5000 Years: A Paleoecological Study Of Iquitos, Annabel Zwarts

Theses and Dissertations

The vegetation of the Amazonian rainforest is hypothesized to have been shaped by pre-Columbian activities, such as burning and palm management to various extents. Management of palms is hypothesized to have caused some of the most useful species to become hyperdominant in Amazonia. This study investigated the extent to which human activities over the past 5000 years affected palm abundances in mature lowland rainforests near Iquitos, Peru. I used phytoliths and charcoal from soil cores to determine the history of local floras, and modern palm surveys to compare modern phytolith occurrence with modern vegetation. Because pre-Columbian activity clustered along the …

Developing A Small Molecule To Inhibit Hsf1 Expression In Cancer And Evaluating Natural Genetic Variation In Small Molecule Toxicity., Michaela Kendal Foley

Theses and Dissertations

Each year cancer affects nearly 20 million people worldwide and genetic differences across populations can impact cancer onset and progression. Specifically, tumors with high levels of HSF1, the master regulator of the cytoprotective heat shock response (HSR), are correlated with poor patient outcomes in multiple cancers such as prostate, breast, and melanoma. Subsequently, the development of pharmacological inhibitors of HSF1 represents a promising strategy for anticancer therapeutics. Using a luciferase-based transcriptional reporter, two small molecule libraries were screened for inhibitors of HSF1 expression in human embryonic kidney cells, yielding ten compounds that decrease HSF1 expression. To identify if cancer lines …

Antimicrobial Eats: How Food Additives Are Contributing To Obesity Via The Gut Microbiome, Olivia Mankos

Senior Honors Theses

The typical modern diet is brimming with food additives used in food processing. Additives such as antibiotic residues, GMOs, pesticide residues, anti-caking agents, emulsifiers, artificial sweeteners, colorants, flavor enhancers, and preservatives. Most of these additives seem to shift the gut microbiome towards more pro-inflammatory signals. When all these additives are considered as an amalgam, such as with the modern processed diet, the ramifications on the gut microbiome are concerning. Obesity, which is characterized by low-level chronic inflammation, is likely exacerbated by these food additives. Consequently, most of these additives should be avoided or banned for optimal health.

Mechanisms Of Behavioral Change In Hosts Of Toxoplasma Gondii: A Review, Olivia Grimsley

Senior Honors Theses

The parasite Toxoplasma gondii is a highly ubiquitous parasite that latently infects an estimated 33% percent of the global population. Toxoplasmosis is of obvious clinical significance due to the extremely high risks to the unborn who contract it congenitally. Less attention has been given to a more subtle aspect of latent infection, which is the behavioral alterations that are commonly experienced by those who contract the parasite. Infected individuals commonly display a variety of altered behaviors, such as increased aggression and risk-seeking behaviors, depression, higher tendency towards suicide and self-directed violence, a loss of fear response, and a greatly increased …

Spatiotemporal Changes In The Imperiled And Diverse Mussel Assemblage Of The Spring River In Kansas In Response To Known And Emerging Pollutants, Joshua Holloway

Electronic Theses & Dissertations

Kansas was historically home to 50 species of freshwater mussels, of which 42 remain extant. The Spring River of southeastern Kansas is home to 34 of the remaining 42 mussels, many of which are imperiled. Elevated metal concentrations that resulted from past lead and zinc mining in the Tri-State Mining District historically imperiled Spring River mussels, but this threat has abated over the last 20 years. Ammonia pollution may have replaced the threat of metals, however, with potentially severe consequences for Spring River mussels. Our objectives were to evaluate contemporary mussel assemblage structure, in addition to spatiotemporal trends in the …

The Roles Of Rnt1 And Putative Endoribonucleases In Eukaryotic Mrna Degradation, Lee-Ann Notice-Sarpaning

Dissertations and Theses (Open Access)

Endoribonucleases initiate degradation by cleaving RNAs internally. Mutations in these enzymes have been shown to cause diseases such as cancer, developmental disorders, and neurodegenerative diseases. Yet, eukaryotic endoribonucleases have not been well studied, especially with regard to their role in nuclear mRNA degradation. Rnt1 is a Saccharomyces cerevisiae (budding yeast) nuclear endoribonuclease and homolog of human Drosha with well-characterized roles in the processing of ncRNAs. The enzyme recognizes and cleaves double-stranded RNA stems containing a terminal tetraloop with an AGNN consensus sequence. However, the scope and consequence of its function in mRNA degradation has heretofore been unclear. Previous studies have …

Leveraging Innate Immune Sensors To Generate Durable Anti-Glioma Adaptive Immune Responses, Spencer Lea

Dissertations and Theses (Open Access)

Glioblastoma is an aggressive primary brain malignancy harboring a tumor microenvironment that is mostly devoid of T cell effector infiltration but is dominated by immune suppressive microglia, macrophages, and myeloid-derived suppresser cells. These innate immune cells display impaired phagocytosis and antigen presentation and are inadequate for triggering the subsequent immune activating signals needed for anti-tumor adaptive effector responses. Glioblastoma tumors can further restrict phagocytosis and subsequent tumor antigen presentation by the upregulation of the antiphagocytic “don’t eat me” ligand CD47. Here we tested whether activation of multiple conserved innate immune pathways could initiate proinflammatory conversion of suppressive myeloid populations, activation …

Identification Of Mitochondrial Defects And Metabolic Consequences In Lynch Syndrome-Related Endometrial Cancer, Mikayla Bowen

Dissertations and Theses (Open Access)

Lynch syndrome (LS), defined by mutations in DNA mismatch repair genes including MSH2, carries a 60% lifetime risk of developing endometrial cancer (EC). Mismatch repair deficiency (MMRd) causes hypermutability, which is assumed to be the main driver of LS-related EC development. However, incomplete penetrance of EC development in women with LS suggests that other modulators are at play. The broad hypothesis of this dissertation is that MMRd causes consequences beyond hypermutability to impact LS-related EC development. Recent studies utilizing our lab’s Msh2-deficient mouse model for LS-EC revealed mitochondrial dysfunction in EC pathogenesis. This new insight led to the …

Unraveling Epigenetic Mechanisms That Regulate Breast Cancer Lung Metastatic Relapse By Rewiring The Immune Microenvironment, Jayanta Mondal

Dissertations and Theses (Open Access)

Metastasis accounts for >90% of cancer-related deaths and thwarting metastasis is widely considered to be the “Holy Grail” of cancer treatment. Breast cancer is the most common cause of cancer-related death among women and is characterized by its proclivity to spread to distant secondary organs like the lungs, and the brain. These disseminated tumor cells lie dormant at the secondary site and can undergo metastatic relapse. Epigenetic alterations are a predominant hallmark of cancer, however, its role in facilitating reawakening of dormant cancer cells and the subsequent metastatic relapse remains to be elucidated. To address this gap of knowledge, we …

Developing Novel Therapies Targeting The Tumor Microenvironment Of Aggressive Breast Cancer, Lan T H Phi

Dissertations and Theses (Open Access)

Triple-negative breast cancer (TNBC) and inflammatory breast cancer (IBC) are the most aggressive breast cancer subtypes. The tumor microenvironment (TME) is critical in driving these aggressive breast cancers' clinical phenotype and aggressiveness. Therefore, we explored novel actionable targets and complementary therapies targeting the TME to improve the outcomes of patients with these cancers.

In this thesis, we identified AXL as a potential therapeutic target in IBC due to its role in generating an immunosuppressive TME. Indeed, inhibiting the AXL pathway suppresses IBC tumor growth and reduces M2 macrophage populations in various mouse models. Mechanistically, AXL facilitates the polarization of M2 …

Impact Of Tumor Cell Expressed Cd38 On Metastasis And Immune Evasion In Breast Cancer, Tanvi Visal

Dissertations and Theses (Open Access)

Triple-negative breast cancer (TNBC) is a highly metastatic breast cancer subtype. The epithelial-to-mesenchymal transition (EMT) of cancer cells is a key feature of the metastatic cascade and is not a binary process but often generates malignant cells with both epithelial (E) and mesenchymal (M) traits known as hybrid EM cells. Recent studies highlight the enhanced metastatic potential of the hybrid EM cells. However, molecular insights and targetable vulnerabilities within hybrid EM remain elusive. We discovered that hybrid EM murine tumors are enriched in CD38, an immunesuppressive molecule associated with worse clinical outcomes in liquid malignancies but relatively understudied in solid …

The Extracellular Domains Of The Ampa, Kainate, And Orphan Delta Receptor Regulate Channel Gating In Distinct Ways, Cuauhtemoc Ulises Gonzalez

Dissertations and Theses (Open Access)

The ionotropic glutamate receptors are ligand-gated cationic channels essential for neuroplasticity and neurological functions such as learning, memory, behavior, cognition, and motor coordination. Mutations in these channels are linked to various disorders including autism, ataxia, and epilepsy, making them compelling pharmacological targets. Within this family, the α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) and kainate receptor mediate their function through fast glutamate-gated ionotropic activity, which needs precise structural changes to perform properly. While Cryo-EM structures have provided snap shots of these proteins, questions remain regarding the dynamics across conformations and individual roles of the extracellular amino-terminal and agonist binding domain in dictating function. …

Evaluating Cancer Rates, Cancer Types, And Variant Hotspots Between Different Races And Ethnicities In Individuals With Li-Fraumeni Syndrome, Hillary Esplen

Dissertations and Theses (Open Access)

Li Fraumeni Syndrome (LFS) is a cancer predisposition syndrome that increases the risk for numerous cancer types in both children and adults. In the general population, incidence rates for various cancer types differ among races and ethnicities. Although a few germline TP53 pathogenic/likely pathogenic (P/LP) variants in those with LFS have been studied and associated with specific populations, such as the South and Southeast Brazil founder variant, p.Arg337His, there still lacks research on the variable expressivity of cancers within the LFS population based on specific variant, race and/or ethnicity. This study aims to describe the specific TP53 germline variants, the …

Relationship Between Processing Body Formation, Epithelial-To-Mesenchymal Transition, And Invasion In Lung Adenocarcinoma, Amanda Warner

Dissertations and Theses (Open Access)

Lung cancer is the leading cause of cancer-related deaths in the United States, largely due to its ability to metastasize. Epithelial-to-mesenchymal transition (EMT) is a process that enhances the ability of cells to lose their cell-cell contacts, invade, and enter the blood stream which are essential during metastasis. Many transcriptional gene programs are altered during EMT such as activation of mesenchymal transcription factors, like ZEB1, and enhanced response to the TGFβ1 cytokine. In oncogenic contexts, TGFβ1 enhances the formation of processing-bodies (P-bodies) where P-body proteins are required for invasion in multiple cancerous cell lines. P-bodies are a type of ribonucleoprotein …

Rod Photoreceptor Regeneration In A Zebrafish Model With Retinitis Pigmentosa, Eyad Shihabeddin

Dissertations and Theses (Open Access)

A cellular hallmark of inherited retinal degenerative diseases is progressive loss of photoreceptors until one is completely blind. Unlike mammalian models, Zebrafish have the ability to naturally regenerate their neurons after injury or disease is detected. We have generated a zebrafish model with the most common autosomal dominant form of the inherited retinal degenerative disease known as Retinitis Pigmentosa. We utilize immunohistochemistry, single-cell RNA sequencing, several analysis tools, behavioral assays and oligonucleotides to characterize our zebrafish model and identify the transcription factors necessary for rod photoreceptor regeneration. We show that our zebrafish model has continuous degeneration and regeneration of rod …