Life Sciences Commons^™

Genetic Screen For Regulators Of Pol4, A Dna Repair Polymerase In Saccharomyces Cerevisiae, Pasang Dolma Sherpa

Theses and Dissertations

In Saccharomyces cerevisiae, DNA polymerase 4 (POL4) is the beta repair polymerase, the product of the POL4 gene, and is involved in base excision repair (BER) and microhomology-mediated end joining (MMEJ). Despite its involvement in these repair pathways and its conservation across eukaryotes, deletion of POL4 shows no detectable phenotype under standard laboratory conditions. I hypothesized that unknown genes act as backup systems, providing redundant activities that allow pol4Δ cells to survive. To test this, a genetic screen for mutants showing synthetic lethality with pol4Δ was implemented. I constructed a strain lacking the POL4 gene and carrying …

Optimizing Citriculture In South Texas With Endemic Hlb, Ruth Lilia Galan

Theses and Dissertations

The Texas citrus industry has a long history of resilience, rebounding from environmental and economic disasters. Over the last decade it has endured several hurricanes, freezes, pests and diseases. Huanglongbing (HLB), a graft-transmissible disease caused by Gram-negative bacterium Candidatus Liberibacter asiaticus which is vectored by the Asian citrus psyllid (ACP) (Diaphorina citri Kuwayama), is an endemic citrus disease posing serious threat to the long-term viability of the industry. Rapid production of high quality nursery trees and effective protection of young citrus transplants from HLB are critical for long term sustainability of citriculture in this region. Studies were performed to improve …

Phenotypic Contribution And Regulation Of Vibrio Parahaemolyticus Cold-Shock Protein Homologue Vp1889, Oleg Borisovich Ermolinsky

Theses and Dissertations

Vibrio parahaemolyticus is the primary causative agent of a form of gastroenteritis called vibriosis commonly acquired from ingestion of raw and undercooked seafood. The primary mitigation of seafood-borne illnesses is immediate storage on ice following catch, which inhibits bacterial metabolism and replication. Mesophilic bacteria such as V. parahaemolyticus induce expression of cold-shock proteins in a process named the cold shock response, which facilitates survival at low temperatures. V. parahaemolyticus bears 3 homologues of the major Escherichia coli cold-shock protein CspA, an RNA chaperone. Induction of E. coli CspA at low temperatures depends on autogenous modulation by its mRNA structure, which …

The Effect Of Drought On Avian Migratory Patterns And Stopover Through Texas And Louisiana, Ian Becker

Theses and Dissertations

Extreme weather events pose a massive threat for native ecosystems. As precipitation and temperature patterns are altered due to climate change, drought may become an incredibly severe event on the landscape. Drought directly impacts resources that migratory birds need during stopover en route to breeding and non-breeding grounds. Here, I quantify the impacts of drought on migration through Texas and Louisiana using 26 years of weather surveillance radar data. To understand how drought interacts with the local environment to impact migration, I tested 4 hypotheses displaying drought’s ability to impact migrants in conjunction with climatic and habitat level characteristics. Fall …

Ethanol State-Dependent Learning In The Honey Bee (Apis Mellifera), Ethan Neil Govea

Theses and Dissertations

Ethanol disrupts neural circuits involved in addiction and withdrawal, yet the molecular mechanisms underlying these effects remain poorly understood. One possibility is that ethanol alters an animal’s perceptual or internal state, causing a stimulus learned while intoxicated to be processed differently when the animal is sober. This study examined how ethanol exposure affects odor learning, recall, and discrimination in honey bees, a useful model because of their robust olfactory learning and experimentally accessible neural systems. Bees were differentially conditioned with appetitive reward (sucrose) during hexanol exposure and aversive stimulus (quinine) during decanol exposure. To assess olfactory processing and state dependency, …

Developing A Qpcr Method For Evaluating Parasitoid Wasps As A Potential Means Of Control Of The Southern Cattle Fever Tick Rhipicephalus (Boophilus) Microplus In South Texas, Abbey Abalos

Theses and Dissertations

Ixodiphagus spp. wasps are natural enemies of ticks that have been reported to cause mortality in multiple tick species. Parasitoid wasps may represent a potential biocontrol alternative to traditional chemical tick control methods, which are challenged by non-target toxicity and the development of pesticide resistance in species of concern such as Rhipicephalus microplus, a pest of livestock that causes billions of dollars in loss to the livestock industry worldwide. Rhipicephalus sanguineus s.l. is a congeneric species of R. microplus, and parasitism of R. sanguineus by Ixodiphagus sp. in areas of co-occurrence has been observed. It is unknown if R. microplus …

The Impact Of Nutrition On Insecticide Resistance And Gene Expression In Aedes Aegypti, Esmeralda Guadalupe Rosas

Theses and Dissertations

The development of insecticide resistance in Aedes aegypti, a major vector of dengue and Zika viruses, threatens vector control efforts, particularly in endemic regions such as South Texas. Insecticides remain widely used; however, their overuse has accelerated metabolic resistance mediated by cytochrome P450 enzymes. Environmental factors such as larval nutrition may influence mosquito physiology and resistance-associated gene expression, yet this relationship remains poorly understood. This study examines how larval nutritional conditions affect the expression of cytochrome P450 genes linked to pyrethroid resistance in Aedes aegypti. Larvae were reared under five dietary treatments differing in lipid and protein ratios, and adults …

Identification Of Peptides For A Muc13 Cancer Vaccine, Abigail Olivia Gomez

Theses and Dissertations

Mucin 13 (MUC13) is a transmembrane glycoprotein that is frequently overexpressed in epithelial cancers. Its extracellular domains and cytoplasmic signaling potential contribute to disrupted cell adhesion, increased invasion, and cancer-promoting pathways, making MUC13 a promising target for immunotherapy. This project used an in-silico approach to identify MUC13-derived peptides predicted to bind HLA class I molecules and support CD8+ T cell-mediated immune responses. Bioinformatics tools were used to screen candidate epitopes for HLA binding affinity, antigenicity, toxicity, IFN-γ-inducing potential, and population coverage, allowing rational prioritization of peptide candidates for experimentation. Selected peptides were evaluated in THP-1-derived macrophages using RT-PCR, Western blotting, …

Linking North American Demographic Trends To Mexican Non-Breeding Grounds In A Migratory Warbler, Majuwana Gamage Dulanthi Dileka Kariyawasam

Theses and Dissertations

Migration enables species to exploit seasonal resources despite high energetic costs and mortality risks, making it a key focus for conservation under environmental change. I investigated migratory connectivity in Orange-crowned Warblers using stable hydrogen isotopes (δ²H) from feathers collected at nine non-breeding sites across Mexico. Results indicated generally weak connectivity (MC = 0.18), with most sites hosting individuals from six breeding clusters across Canada and the United States. However, one northwestern breeding group showed strong connectivity, suggesting crosswise migration to eastern Mexico. By integrating these findings with long-term Breeding Bird Survey data, I detected contrasting population trends, with Pacific Coast …

Analyzing Criteria Air Pollutants And Meteorological Parameters In The Rio Grande Valley, Laredo, And Corpus Christi Region Of South Texas, Angela Garcia

Theses and Dissertations

Recently, the Rio Grande Valley has experienced significant population growth due to economic opportunities, cross-border commerce, SpaceX, and the Rio Grande and Texas liquid natural export terminal presence. The Rio Grande Valley has an estimated population of 1,368,723. This region is largely understudied, along with nearby urban centers such as Laredo and Corpus Christi. The Rio Grande Valley and Laredo regions are a concern due to their population growth and heavy cross-border transportation. Data from the Texas Commission of Environmental Quality Continuous Ambient Monitoring Sites was collected from January 1st , 2024, to December 31st, 2024. Statistical analysis, such as …

Investigating The Ability Of Foxo1 To Maintain Stem Cells, Stella Aime Rios

Theses and Dissertations

Forkhead box O (Foxo) transcription factors are key regulators of stem cell identity and tumor aggressiveness. Prior work from our group and others demonstrates that Foxo factors maintain stem-like states across diverse biological systems; however, the mechanisms by which Foxo1 suppresses differentiation remain poorly defined.

Using C2C12 myoblasts as a model, we investigated whether Foxo1 preserves stem-like programs through regulation of the nuclear pore protein Nup210. RNA interference was used to generate Foxo1 knockdown cells, followed by qRT-PCR, RNA-sequencing, and fluorescence microscopy. Transcriptomic analysis revealed widespread gene expression changes involving metabolic, mitochondrial, and transcriptional pathways. Notably, Nup210 expression was significantly …

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 …

Studies On The Contribution Of Osh6 To The Functions Of Late Endosomes, William King

Theses and Dissertations

The late endosome (LE) is a hub organelle connecting endocytic, biosynthetic, exocytotic, and autophagic vesicle traffic pathways. Malfunctions of LEs are associated with multiple age dependent diseases such as Parkinson’s disease (PD). Despite this significance, how cells refurbish lipids and proteins to LEs to maintain their sustained activities are not clear. Previous studies in the model organism budding yeast show that up-regulation of a lipid transporter Osh6 (PERG6-OSH6) accumulates phosphatidylinositol-4-phosphate (PI4P) on the trans-Golgi network. It also promotes vacuole fusion and maintains the robustness of vacuoles in aged cells. Since LEs are the organelle between the TGN and vacuoles in …

Improving Reclamation Seeding Success Through Seed Technologies, Surface Preparation, And Microbial Inoculants, Josh M. De Santiago Lazalde

Theses and Dissertations

Revegetation of reclaimed lands is often limited by poor seed placement, unfavorable surface conditions, and reduced biological activity, particularly on steep or physically degraded substrates where broadcast seeding is commonly used. Improving early seeding establishment under these conditions requires approaches that address both physical and biological barriers to seedling development. We evaluated the effectiveness of surface preparation, seed technologies, and microbial inoculants for improving plant establishment in field and greenhouse settings relevant to mineland reclamation. At the field scale (Chapter 1), we investigated the effects of chain harrowing and seed enhancement treatments on the establishment of grasses, forbs, and shrubs …

Impacts Of Arbuscular Mycorrhizal Fungi And Novel Soil Amendments On Perennial Grass Establishment In Mineland Soils, Melissa M. Burrell

Theses and Dissertations

Establishing perennial vegetation on mine waste materials is one of the primary challenges in mine land reclamation. Waste rock and mine tailing substrates typically lack the physical structure, nutrient availability, and biological communities necessary to support plant establishment and long-term ecosystem recovery. As a result, revegetation efforts often experience poor seeding success and limited plant persistence despite intensive management efforts. These studies investigated two complementary strategies to improve perennial grass establishment in degraded mine substrates: restoring mycorrhizal associations and enhancing soil function through soil amendments. The first study examined the role of arbuscular mycorrhizal fungi (AMF) in facilitating plant establishment …

Psoas Muscle Volume Asymmetry, Not Attachment Site Asymmetry, Is Associated With Chronic Low Back Pain Status, Kassity D. Clay

Theses and Dissertations

Chronic low back pain (CLBP) is a leading cause of disability worldwide, with increasing evidence implicating neuromuscular factors such as muscle asymmetry in its pathophysiology. The psoas major muscle (PMM), a key contributor to lumbar spine stability, has been comparatively under-investigated despite its biomechanical importance. PURPOSE: To determine whether right-to-left differences in PMM volume and attachment site asymmetry are associated with CLBP; to evaluate whether ODI, IPAQ, and age are associated with PMM volume imbalance; and to assess whether combined PMM volume and attachment asymmetry are associated with CLBP. METHODS: A retrospective secondary analysis was conducted using lumbar MRI data …

Tracing Microplastics From Polymer-Coated Urea: Urban To Agricultural Pathways And Environmental Fate, Caden Joseph Seely

Theses and Dissertations

Polymer-coated urea (PCU) is widely used as a slow-release nitrogen (N) fertilizer because it improves N use efficiency and reduces losses through leaching, denitrification, and volatilization. However, the polymer coating raises concerns about potential microplastic (MP) transport to surface waters following fertilizer application. This thesis evaluates the off-site transport of MPs and associated nutrient and sediment losses from PCU in both urban landscape and agricultural systems. In the urban landscape study, treatments included sod, mulched beds, and water-efficient ground cover receiving uncoated urea, PCU, or liquid slow-release N at 225 kg N ha⁻¹ (with reduced rates for beds and ground …

Optimizing Seedling Emergence In Sagebrush-Steppe Restoration: The Role Of Sowing Depth, Seed Coatings, And Microsite Amendments, John Thomas Stromberg

Theses and Dissertations

Seedling survival of fall-sown seeds over the winter and subsequent emergence in spring is a major demographic bottleneck limiting recruitment in dryland restoration. Deeper sowing can place seeds in a more favorable soil environment with more stable moisture and moderated temperatures, but emergence from these depths is often constrained by the greater distance seedlings must grow to reach the surface and by mechanical resistance in the upper soil layer. In the first chapter of this thesis, we evaluated the use of a slow-release gibberellic acid (GA₃) polymer seed coating to aid in seedling emergence from deeper sowing depths. We compared …

Biophysical Insights Into A Cryptic, Hydrophobic Binding Site On Pcna, Alexis Dispensa

Theses and Dissertations

Proteins are dynamic molecules whose functional landscapes extend beyond static structural representations. Transient cryptic pockets (buried cavities that emerge through protein motion) represent underexplored targets for allosteric regulation and drug discovery. General anesthetics are small, lipophilic, weakly polar molecules that are well suited to partition into such hydrophobic sites. In this work, environment-sensitive fluorescence, photoaffinity labeling, mass spectrometry, mutational analysis, and microsecond molecular dynamics simulations were integrated to discover and characterize a cryptic, highly apolar binding site within the hydrophobic core of human proliferating cell nuclear antigen (PCNA), a central scaffold in DNA replication and repair. Using the solvatochromic fluorescent …

Hybrid Bermudagrass Dormancy Management In A Cool-Season Climate, Clarissa H. Peterson

Theses and Dissertations

Hybrid bermudagrass (Cynodon dactylon [L.] Pers. × C. transvaalensis Burtt Davy) (HBG) is a water efficient warm-season turfgrass increasingly adopted in cool-season and semi-arid regions due to climate change and the demand for reduced irrigation inputs. However, prolonged winter dormancy limits its visual quality (verdure) and seasonal performance. This thesis evaluated multiple management strategies to modify dormancy dynamics and improve off-season turf quality in a cool-season environment. Field experiments assessed the effects of growth covers, fertilizers, colorants, surfactants, organic acids, and overseeding with cool-season species on HBG dormancy over two seasons. Dormancy responses were quantified using normalized difference vegetation index …

Redox Reprogramming In Neurogenesis: Candidate Developmental Switches And Targets Of Oxidative Toxicity In The Redox Proteome, Ryan Jacob Summerhays

Theses and Dissertations

Neurogenic differentiation requires coordinated redox regulation, yet how reversible cysteine oxidation is remodeled at proteome scale during this process remains poorly defined. Here, we asked whether differentiation is associated with selective, site-specific changes in reversible cysteine oxidation and whether oxidative stress reveals developmentally conditioned vulnerabilities within this redox landscape. To address this, we applied a discovery-oriented, proteome-scale redox profiling strategy that quantifies condition-dependent changes in reversible cysteine oxidation using CysPAT labeling, phosphopeptide enrichment, and multiplexed TMT mass spectrometry. Neurogenic differentiation was characterized by reproducible, bidirectional, and highly site-specific remodeling of reversible cysteine oxidation at discrete regulatory nodes, as well as …

Transcriptomic Analysis Of Xeroderma Pigmentosum Group C Skin Samples, Austen N. Gleave

Theses and Dissertations

Xeroderma Pigmentosum is a rare genetic disorder caused by defective DNA damage repair enzymes. This condition results in an increased risk of developing skin cancer and other symptoms in those affected. In this thesis, we examined the effects of Xeroderma Pigmentosum on gene expression in patient skin biopsy samples. To accomplish this, we utilized statistical analysis of spatial transcriptomic and single-cell RNA sequencing techniques to discover differences between patient and heterozygous carrier skin samples. We found that the skin samples from Xeroderma Pigmentosum patients showed elevated levels of inflammation, immune activation, and cellular stress, while the carrier skin samples leaned …

What Happens After The Program Ends? Maintenance Of Physical Performance And Resistance Exercise Participation Following Exercise Oncology Interventions, Alexander Matthew Brooks

Theses and Dissertations

BACKGROUND: Cancer survivors frequently experience persistent impairments in physical performance that compromise functional independence, quality of life, and long-term health. While supervised exercise programs meaningfully improve physical performance, there is uncertainty regarding the durability of these benefits and the factors that influence long-term participation after programs end. Although exercise oncology programs typically include both aerobic and resistance exercise (RE), participation in RE tends to decline once supervision ends and remains lower than aerobic exercise over time. Therefore, the overarching aims of this dissertation were to: 1) evaluate the sustainability of physical performance improvements following exercise interventions in cancer survivors; 2) …

Assessing The Variabilities In Environmental Pollution, Health, And Socio-Economic Characteristics Of Communities In South Carolina, Subrena Alam

Theses and Dissertations

This study examined how environmental pollution, health conditions, and socio-economic characteristics vary across South Carolina (SC), and attempted to identify communities that face the increased environmental and public health risks. A geospatial dataset of environmental (air and water quality-related) as well as socio-economic indicators obtained from the U.S. Environmental Protection Agency (EPA)'s EJScreen platform (currently defunct) were used to assess spatial variability across the state. Results of our analysis indicated that communities in the Upstate region of SC appeared to be under the greatest environmental pollution risks. The Pee Dee region had the highest proportion of people of color and …

Comparing Stress Levels And Experiences Between Mothers And Fathers Of Children With Angelman Syndrome, Katherine Helen Fix

Theses and Dissertations

Angelman syndrome (AS) is a neurogenetic disorder characterized by significant developmental and cognitive impairments, disruptive behaviors, and a hallmark happy demeanor. Past studies have shown that certain features of AS contribute to increased parental stress. Other studies report that in general the stress of parents of children with disabilities is influenced by stereotypical gender roles surrounding factors including daily care taking tasks, financial responsibility, and medical care involvement. This study aimed to compare perspectives among mothers and fathers of individuals with AS to identify discrepancies and themes relating to stress, specific hardships, and caregiving roles. Parents of children with AS …

Student Insights On The Most Valuable Aspects Of Genetic Counseling Programs’ Online Presence During The Application Process, Anna Cathryn Girten

Theses and Dissertations

When applying to genetic counseling graduate programs (GCGPs), past research has demonstrated that students prefer websites that are updated and easy to navigate. Program websites contribute to students’ first impressions of the program and serve as an important source of information, but there is limited research on the role of social media and other online content during the application process. This study aimed to identify the importance of online platforms and helpfulness of specific content for students applying to GCGPs. An electronic survey was distributed to current students and recent graduates of accredited genetic counseling programs, and 148 responses were …

Assessing Hereditary Cancer Risk And Genetic Counseling Knowledge And Interest In Appalachian Kentuckians, Ashton Farmer

Theses and Dissertations

Appalachian Kentucky has the highest cancer incidence in the United States and about 5-10% of all cancer has a hereditary cause. Despite this, there are no board- certified genetic counselors located in the area, and few genomic studies have been done in this population. This study aimed to define Appalachian Kentuckians’ interest in cancer genetic counseling and knowledge of cancer risk factors. An original online survey including multiple choice, Likert scale, and open response items was utilized to assess interest in pursuing cancer genetic counseling and how knowledge of cancer causes impacts interest in cancer genetic counseling. A total of …

Resting-State Functional Connectivity Of Dopaminergic Reward Pathways Across The Adult Lifespan, Julia Cardarelli

Theses and Dissertations

This study investigates the effect of age on three major dopaminergic reward pathways using resting state functional magnetic resonance imaging. Resting state imaging refers to low-frequency brain connectivity in the absence of task demands or directed thought patterns. The pathways included in this thesis are as follows: the nigrostriatal, mesolimbic, and mesocortical pathways. These pathways rely on dopamine and are known for a variety of functions, most notably regulating responses to rewarding and aversive stimuli. This analysis compared the connectivity between key regions of interest, where transmission originates in the midbrain and substantia nigra, and terminates in the orbitofrontal cortex, …

Soil Macroinvertebrate Biodiversity Patterns In Congaree National Park And The Role Of Dna Barcoding, Sharon Ann Kendrick

Theses and Dissertations

Soil and leaf-litter invertebrates are important components of terrestrial biodiversity and contribute to key ecosystem processes such as decomposition, nutrient cycling, and soil formation. Despite their ecological importance, these communities remain difficult to document because many taxa are small, cryptic, or challenging to identify using morphology alone. This study examined patterns of soil macroinvertebrate biodiversity across habitats within Congaree National Park while also evaluating the usefulness of DNA barcoding for documenting taxonomic diversity. Sampling was conducted at 39 sites between September 2022 and October 2024 across upland, bottomland, and bluff habitats. Macroinvertebrates were collected separately from leaf litter and soil …

Developing Drosophila Melanogaster As An In Vivo Model Of Diet- Induced Chronic Inflammation, David Jonith Duncan

Theses and Dissertations

Diet impacts organismal health. Sub-optimal diets, such as obesogenic diets, can lead to long-term detrimental health effects. Over 60% of adults in the United States are overweight or obese, however the link between obesity and associated disease, such as chronic inflammation, remains unclear. Drosophila melanogaster is a useful in vivo model to better understand the effects of obesogenic diets on the immune response and begin examining the potential therapeutics of dietary plant compounds. Thus far, we find there is a difference in lifespan and reproduction patterns across the different control lines fed different standard diets. Oregon-R and yw control lines …