Digital Commons Network^™

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 …

Resource Allocation Trade-Offs Between Longevity And Reproduction In Daphnia Magna, Amelia Pearson

Electronic Theses and Dissertations

Although trade-offs between longevity and reproduction have been described for a long time, the genetic mechanisms by which organisms modulate allocation of resources between these two essential processes remain poorly understood, due to their complex nature and their modification by existing nutritional states and environmental cues. Daphnia magna represents a valuable model for investigation in this area due to their moderate lifespan and cyclic parthenogenetic mode of reproduction, allowing for the easy study of gene by environment interactions. This dissertation first investigates the change in mortality, reproduction, activity, and gene expression when fully fed Daphnia and calorically restricted Daphnia are …

Adventitial Macrophage Accumulation Impairs Perivascular Nerve Function In Mesenteric Arteries With Inflammatory Bowel Disease, Elizabeth A. Grunz, Benjamin W. Jones, Olubodun Michael Lateef, Sidharth Sen, Katie Wilkinson, Trupti Joshi, Erika M. Boerman

Biomedical Sciences

Introduction: Inflammatory bowel disease involves aberrant immune responses and is associated with both cardiovascular disease risk and altered intestinal blood flow. However, little is known about how inflammatory bowel disease affects regulation of perivascular nerves that mediate blood flow. Previous work found perivascular nerve function is impaired in mesenteric arteries with Inflammatory bowel disease. The purpose of this study was to determine the mechanism of impaired perivascular nerve function.

Methods: RNA sequencing was performed on mesenteric arteries from IL10−/− mice treated with H. hepaticus to induce disease (inflammatory bowel disease) or left non-gavaged (Control). For all other studies, Control and …

Effects Of Weight Loss Medications In Combination With Psychotropic Medications, Emily A. Hoffman

Electronic Theses, Projects, and Dissertations

Background and aims: The obesity epidemic has been well-documented and weight loss medications are becoming increasingly popular. Patients with psychiatric conditions often suffer metabolic side effects from psychotropic medications and are often prescribed weight loss medications to mitigate these side effects. When treating patients on these medications concurrently, understanding their potential side effects is essential for developing an effective care plan. Registered dietitian nutritionists (RDNs), pharmacists, and mental health professionals working in mental health facilities should be aware of these potential side effects to better care for their patients.

Methods: After completing a thorough literature review, a handbook …

Tips For Health Care Practitioners: A Guide For Adolescent Obesity, Regina Santana

Electronic Theses, Projects, and Dissertations

Adolescent obesity continues to be a significant public health concern that is associated with long term physical consequences. The purpose of this project was to develop an evidence based, user friendly guidebook that supports healthcare professionals in the education of adolescents with obesity and their families. A structured literature review development process was used to inform the current development of the guidebook. The guidebook includes components of obesity management such as nutrition and physical activity recommendations. The validity of the content was established through the evaluation of five healthcare professionals that include registered dietitians and licensed therapists. The guidebook was …

Can Carpobrotus Edulis Cause Significant Changes To The Soil Microbiome?, Samantha J. Cowan

Electronic Theses, Projects, and Dissertations

Invasive species cause significant damage to ecosystem biodiversity and can cost billions of dollars to restore native species (Van der Wal et al, 2008; Diagne et al., 2021).  In certain instances, even if the invasive species are removed, they can leave legacy effects on the environment that make restoration more challenging (Conser and Connor, 2008; Elgersma et al., 2011). Carpobrotus edulis is an invasive species of plant that is known to cause changes to its environment such as affecting the soil nitrogen cycle and the pH, potentially leading to persistent changes in the soil microbiome and causing native species to …

Quantifying Macrophyte Ecosystem Services And Improving Environmental Nonprofit Messaging, Peyton R. Hughey

All Theses

Environmental nonprofits are essential to the management and restoration of our natural spaces. They are also tasked with engaging the public via outreach, education, and advocacy. As natural spaces are degraded, the ability of environmental nonprofits to deliver on their missions will become increasingly important. This study aimed to improve two approaches to environmental nonprofits’ missions: ecological restoration and social media communication.

Environmental nonprofits operate with limited resources, and ecological restoration can be an exhaustive task; therefore, we explore functional restoration as a tool. In this study, we focus on the use of functional, trait-based restoration to restore ecological function …

Mining The Usda Snap Bean Association Panel For Resilience: Genetic Dissection Of Heat And Disease Tolerance In Snap Bean, Atiya F. Khan

All Theses

Snap bean (Phaseolus vulgaris L.) is an economically and nutritionally important vegetable crop whose production is increasingly threatened by rising temperatures and emerging bacterial diseases, particularly in the southeastern United States. Heat stress during reproductive development can significantly reduce yield, while newly emerging pathogens such as Pseudomonas capsici present additional risks to crop productivity. This study leveraged the USDA Snap Bean Association Panel (SnAP) to investigate the genetic basis of heat tolerance and disease resistance and to identify germplasm and genomic regions useful for breeding resilient cultivars.

To evaluate heat tolerance, a subset of the SnAP panel was …

Micro-Solar Kiln Design: A Cost-Effective Approach For Small Landowners To Produce Higher Quality Lumber, Bart Swecker

All Theses

Small-scale and hobby sawmill operators increasingly seek low-cost methods for drying lumber to moisture contents suitable for interior use, yet conventional kiln systems are often impractical due to capital cost, power requirements, and operational complexity. While air drying remains common at small scales, many operators require a controlled finishing step to improve dimensional stability and product value. Solar kilns offer an intermediate solution between air drying and conventional kilns; however, most published designs and performance data focus on systems with capacities far larger than those typically used by small-scale operators. Consequently, limited guidance exists for micro-scale solar kilns, particularly under …

Biology, Ecology And Control Of Eye Gnats In An Open Pine Ecosystem, Leela Hospach

All Theses

Eye gnats of the genus Liohippelates are bothersome flies of the family Chloropidae. They breed in moist, disturbed, sandy soils that contain organic matter, and have been implicated as vectors of conjunctivitis, bovine mastitis, and yaws. We conducted research into some basic biological and ecological characteristics. Using wild-caught gnats in a temperature-controlled incubator, we found that their activity peaks between 27°C and 41°C. Trapping at different heights above the forest floor in an open-pine savannah, we captured most gnats at 7.5 m off the ground. This may have to do with the attractiveness of the rotten egg lures we used, …

Characterizing The Molecular Response Of Embryonic Zebra Finch To Acute Sound Playback, Saidat O. Adeniran-Obey Miss

All Theses

Auditory stimuli are important cues that influence developmental plasticity in animals and are important for development and adaptation to an ever-changing environment. In the zebra finch (Taeniopygia guttata), there is evidence of adaptive developmental reprogramming in response to a prenatal ‘heat call’. Embryos exposed to this heat call exhibit changes in growth rate post-hatch, increased heat resistance, and enhanced reproductive success at maturity. However, it has long been assumed that embryonic zebra finches cannot respond to sound due to the immaturity of their auditory system. These findings raise the critical question of whether late-stage zebra finch embryos can, …

Comparative Biomechanics: Blattodea Antennal Morphology And Physiology, Lucas W. Marsh

All Theses

Equipped with muscle-free antennae, many insects can twist and bend their antennae on demand. We hypothesized that hemolymph circulating through the antennae provides pressure that facilitates twisting and bending and provides a feedback control channel for tactile sensing in insects. To test this hypothesis, we conducted a thorough morphological and physiological analysis of antennae in three Clades of Blattodea. We studied morphology by evaluating the distinguishable features of the body and antenna, as well as the internal structure of the antennal lumen. Then, in a series of experiments on live cockroaches, we measured blood pressure along the antenna. This was …

Ontogeny And The Effects Of Perinatal Stress In The First Immature Skeleton Of Teleoceras Aepysoma (Perissodactyla, Rhinocerotidae), Joe Gajewski

Electronic Theses and Dissertations

Recovery of an immature fossil rhinoceros (Teleoceras aepysoma) skeleton (ETMNH 32999) from the Gray Fossil Site in Tennessee offers the first insights into the ontogeny of the species. ETMNH 32999 is interpreted to be a subadult male in an age class equivalent to ~17-20% of potential lifespan. Comparative analyses support the hypothesis that subadults of related taxa are typically ~91% of average adult size in most dimensions. However, certain cranial dimensions are substantially lower than expected in ETMNH 32999, averaging only ~74% of the average conspecific adult. Such departure from typical growth rates is suggested to be attributable …

Assessment Of Super Absorbent Polymer In Soybean Cultivation Under Variable Irrigation Conditions In Nebraska, Ankit Chandra, Abia Katimbo, Ronaldo Marchezan, Martha Nabaggala

Department of Agricultural and Biological Systems Engineering: Presentations and White Papers

Water limitation is a primary constraint to soybean productivity in both irrigated and rainfed systems. Soil-applied superabsorbent polymers (SAPs) have been proposed as a strategy to buffer crops against episodic drought stress; however, their physiological and agronomic performance under varying irrigation regimes remains insufficiently quantified. Here, we evaluate three biodegradable polymer formulations: broader granules (BB), original granules (OG), and powder (PWR) applied at low (17.7 lb/ac) and high (120 lb/ac) rates under full (100% ET), reduced (50% ET), and no irrigation conditions in western Nebraska. Polymer application had negligible effects under full irrigation, with yields comparable to untreated controls. Under …

Wrky Transcription Factors: Integral Regulators Of Defence Responses To Biotic Stress In Crops, Dongjiao Wang, Ruize Zhang, Wenhui Zou, Yuanyuan Zhang, Wanying Zhao, Tingting Sun, Qibin Wu, Zheng Qing Fu, Youxiong Que

Faculty Publications

Crops are continually challenged by biotic stresses, including fungal, bacterial and viral pathogens and insect pests, which cause substantial yield and quality losses worldwide. WRKY transcription factors constitute a plant-specific and functionally diverse family that is central to immune regulation. Recent advances in genomic resources and multi-omics approaches have accelerated the identification and functional characterisation of WRKYs in crops. This review summarises the structural features and classification of WRKY genes and their genome-wide distribution across crop species. It also synthesises WRKY-centred regulatory modules that mediate resistance to major classes of biotic stress. In antifungal defence, WRKYs reinforce pattern- and effector-triggered …

Vitaltitration Predicts Fermentation Performance Of Phylogenetically Distinct Saccharomyces Cerevisiae Yeast Strains, Samantha White Ms

All Student Scholarship

Accurate assessment of yeast physiological health is essential for achieving consistent, efficient, and predictable beer fermentations. Although yeast vitality is more predictive of fermentation performance than viability alone, no universally adopted vitality assay currently exists in the brewing industry. This thesis investigates vitaltitration (VT) as a rapid, robust, and brewery-feasible method for quantifying yeast vitality and predicting fermentation performance. We hypothesize that VT provides a reliable measure of metabolic competence that correlates with fermentation kinetics across brewery-relevant yeast strains. To test this hypothesis, VT was evaluated alongside Acidification Power (AP) in structured serial-fermentation experiments in two phylogenetically distinct brewing yeasts: …

Diacylglycerol Kinase Eta As A Novel Target In Nras Mutant Melanoma, Haley P. Wilson, Casey D. Stefanski, Signe Caksa, Glenn L. Mersky, Scott D. Varney, Jelan I. Haj, Dan A. Erkes, Timothy J. Purwin, Vivian Chua, Andrew E. Aplin

Department of Pharmacology, Physiology, and Cancer Biology Faculty Papers

NRAS mutations occur in 10%-30% of cutaneous melanomas and are associated with high tumor mutational burden. Mutant NRAS signaling drives aberrant cell growth and proliferation, in part, through activation of the RAF-MEK-ERK1/2 kinase pathway; however, targeted therapies to this pathway have limited effectiveness in patients with NRAS mutant melanoma. The role of other targetable signaling pathways in NRAS mutant melanoma is poorly characterized. Here, we demonstrated that one isoform of diacylglycerol kinase, diacylglycerol kinase eta (DGKη), a lipid signaling regulator, was highly expressed in NRAS mutant melanoma patient samples. Knockdown of DGKH in NRAS mutant melanoma cell lines resulted in …

Emotional Intelligence Documentary - The Journey, Not The Destination: A Spain Reflection, Elise I. Palacios

Cultivating Emotional Intelligence through the Humanities in Spain

The Journey, Not the Destination follows my study abroad experience in Madrid and Toledo, Spain through a Medical Humanities course. Through art, history, culture, and personal reflection, I explore how travel broadened my understanding of the human experience and shaped my perspective as a future physician. More than a story about a place, this documentary is about growth, empathy, and the lessons we learn along the journey.

Ecological Responses To Living Shoreline Restoration, Aaron S. Bland

Graduate Theses and Dissertations (2019 - present)

Coastal built communities and natural coastal ecosystems face similar and interrelated hazards: shoreline sediment erosion, shoreline retreat, and worsening storms, each of which is exacerbated by relative sea level rise. Living shorelines are coastal defense projects that incorporate natural habitats to provide more sustainable shoreline defense and improve the coastal ecosystem. Living shorelines have been widely adopted, but their performance has been highly variable, and the mechanisms of project success and failure are unclear. The overarching goal of this dissertation was to better understand the ecosystem responses to coastal restoration, focusing on the primary habitats of coastal salt marsh and …

2nd Place Research Paper: Shaping The Ape: Storytelling, Cultural Reflection, And Boundary Negotiation In Human-Ape Zoo Encounters, Abigail Bond Halling

Kevin and Tam Ross Undergraduate Research Prize

The typical Western zoo functions as a unique environment in which animals are frequently positioned as subjects of education and entertainment through the medium of storytelling. In this sense, the zoological institution can also be read as an extension of popular Western constructions surrounding nonhuman animals, particularly those who are symbolically charged characters in our collective imaginary– the great apes. Given the morphological, behavioral, and psychological similarities between humans and other great apes (chimpanzees, gorillas, and orangutans), nonhuman great ape enclosures at the Western zoo become spaces where humans are most radically confronted with navigating the boundaries of the “human-animal …

Awe As Signpost: An Argument For The Consistency Of Lewis’S “Joy” And Psychological Awe, Audrey Hendricks

Senior Honors Theses

C.S. Lewis’s Surprised by Joy details Lewis’s autobiographical apologetic for the existence of God through his experiences of “Joy,” a technical term invented by Lewis. Upon close study, his experiences of Joy contain many similarities to psychological awe. This investigation compares Lewis’s Joy with psychological awe using the Awe Experience Scale (AWE-S) to determine consistency. Lewis’s Joy was found to be consistent with all six criteria of the AWE-S in addition to other recognized psychological characteristics of awe. In addition to qualitative consistency, this review also argues for the teleological consistency of the two concepts, contending for a Christian teleological …