Life Sciences Commons^™

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 …

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 …

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 …

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 …

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 …

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 …

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 …

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 …

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 …

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 …

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 …

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 …

The Role Of Emerin In Myogenic Differentiation, Nicholas Marano

Theses and Dissertations

The nucleus harbors genetic material encapsulated by the nuclear envelope which is composed of an inner and outer nuclear membrane. The establishment and organization of chromatin at the INM is essential for cell fate during the differentiation program. Integral INM proteins are responsible for chromatin organization at the nuclear envelope. Emerin is a highly conserved type II integral INM protein with roles in chromatin organization, cell signaling, and nuclear structure. Mutations in the emerin gene cause Emery Dreifuss Muscular Dystrophy 1 (EDMD1). Emerin is ubiquitously expressed, but loss of emerin function affects specifically skeletal muscle and cardiac tissue. The precise …

Jackfruit Peel Valorization Through An Integrated Biorefinery Approach, Rohil Kumar K Mr

Theses and Dissertations

Jackfruit (Artocarpus heterophyllus) peel (JFP), an abundantly available lignocellulosic biomass, remains largely underutilized despite being rich in cellulose, hemicellulose, lignin, and pectin. In India, approximately 13,460 hectares are under jackfruit cultivation, with Panruti in Tamil Nadu as a major production zone. The discarded peel often contributes to environmental pollution and greenhouse gas emissions. The present study emphasizes sustainable valorization of JFP through an integrated biorefinery framework for generating value-added bioproducts.

Major biopolymers, cellulose, hemicellulose, lignin, and pectin were extracted and fractionated, followed by detailed physicochemical characterization using FTIR, NMR, XRD, SEM, TGA, DSC, GPC, and BET analyses. Pectin extraction with …

Metagenomic Profiling Of Gut Microbiome Signatures Across Liver Disease Stages And Hcv-Related Hepatocellular Carcinoma In Egyptian Patients, Marwa A. Zahra

Theses and Dissertations

Dysbiosis in the gut microbiome, particularly concerning the synchronous crosstalk between the gut and the liver, has been associated with various diseases. This study profiles the gut microbiome in liver diseases among Egyptian patients, with a focus on the hepatitis C virus (HCV) and hepatocellular carcinoma (HCC), both of which are highly prevalent in Egypt. Utilizing shotgun metagenomic sequencing, we analyzed microbial gene catalogs and taxonomic profiles from 46 Egyptian patients categorized into five groups: healthy individuals, liver disease patients of different etiologies, post-HCV, treated HCV, and HCV-HCC patients. Healthy and treated HCV patients exhibited distinct microbial profiles characterized by …

Mycobacteria Infection Induced Cascade Of Epigenetic Alterations Promote Training In Bystander Macrophages, Shah E. Jahan Gulzar Mr

Theses and Dissertations

Mycobacterium tuberculosis (Mtb) remodels host cell functions to support its intracellular persistence. While the effects of Mtb infection on infected macrophages are well characterized, responses of uninfected bystander cells in the same microenvironment remain poorly understood. Here, we show that Mtb infection triggers widespread epigenetic reprogramming not only in infected macrophages but also in neighbouring bystander cells. These bystander macrophages acquire active chromatin marks, exhibit distinct transcriptional changes, and display enhanced immune responsiveness, thereby increasing resistance to both homologous and heterologous infections. We identify interleukin-1 beta secreted by infected cells as a key mediator of this process. Functionally, trained bystander …

Assessing The Effectiveness Of A Habit Recording Tool To Improve Mental Health Of University (Auc) Students, Noran Nounou

Theses and Dissertations

Introduction: According to previous research, the mental health of university students has become an alarming public health concern worldwide. Most of the mental disorders begin among young adults, attributed to the transition to university and increased financial and societal pressure. Despite the important effect of daily habits on mental health, there still remain research gaps in Egypt in exploring their effect among university students and exploring the potential opportunities to support their well-being. Objectives: To assess depression rates among AUC students and to evaluate the effectiveness of a newly designed habit recording board, Make an Impact (MAI) to improve depression …

Mechanical Characterization And Modeling Of Rat Myocardia Under The Influence Of Epirubicin, Abdallah Mahmoud Alkhaiyat

Theses and Dissertations

Cancer remains a predominant health challenge that is responsible for a significant portion of global morbidity and mortality. Epirubicin (EPI), a chemotherapeutic anti-cancer drug, has shown remarkable efficacy in combating various malignancies. However, it is known to have undesirable side effects on the heart, collectively referred to as cardiotoxicity. This research investigates the adverse effects of chemotherapy on cardiac contractility through an in vitro examination of the mechanics of healthy and infarcted animal heart tissues. Electrically stimulated slices of rat ventricular tissue were tested using an isometric force measurement tissue bath. The tissue slices were subjected to uniaxial stretching, allowing …

An Impact Assessment Of The Effectiveness Of Utilizing Informal Health Communication Interventions To Spread Health Recommendations And Change Public Perception, Lina Mohamed Ezzat Ahmed Abdel Mawgoud

Theses and Dissertations

Brain health is an increasingly urgent but critically under-addressed public health priority in Egypt and the wider MENA region. Despite its centrality to aging, productivity, and overall quality of life, public understanding of brain health remains limited, and stigma continues to shape responses to dementia and cognitive decline. This study evaluates the effectiveness of informal, culturally adapted health communication as a tool to shift perception, increase awareness, and promote behavior change among non-medically trained adults in Egypt.

Grounded in global evidence on cognitive reserve, neuroplasticity, and the life-course approach to brain health, the intervention translated expert-informed brain health recommendations into …

Targeting The Cd47/Calreticulin Axis In Triple Negative Breast Cancer Using Ha Grafted Chitosan Nanoparticles Loaded With Doxorubicin And Polygodial, Hadir M. Emara

Theses and Dissertations

Background: Triple-negative breast cancer (TNBC) is considered the most aggressive subtype of breast cancer. Although progress in cancer treatment has led to better results for different types of breast cancer, TNBC remains particularly challenging due to persistent resistance to both chemotherapy and immunotherapy. This resistance ultimately renders chemotherapy less effective and is frequently associated with substantial side effects. Immunosurveillance significantly impacts the onset of cancer, the rise of resistance to therapies, and the likelihood of tumor recurrence. In this immunomodulatory process, Cluster of Differentiation 47 (CD47) and Calreticulin (CALR) are two key regulators. CD47 expression is strongly linked to anti-phagocytic …

Comparative Evolution Of Caenorhabditis Hermaphrodites, James Francis Kennedy

Theses and Dissertations

The Caenorhabditis genus produced three independently-evolved hermaphroditic species, C. elegans, C. briggsae, and C. tropicalis. This convergence happened by the independent co-option of male programs for use in a female body. This required two distinct steps: (1) mutations in the sex-determination pathway that activated spermatogenesis in XX animals, and (2) mutations that expressed one of the redundant sperm activation signals in XX animals. My project focused on characterizing how sex-determination genes work in C. briggsae and C. tropicalis. Loss-of-function alleles were used to compare the core sex-determination pathway to that of C. elegans. I found that the somatic sex-determination pathway …