Digital Commons Network^™

Tradeoffs Between Elemental Homeostasis And Growth Govern Freshwater Phytoplankton Responses To Salinization, Samuel A.T. Dias, Clay Prater, Adriana Diaz-Delgado, Natalie A. Clay, Sally A. Entrekin, Michelle A. Evans-White

Entomology and Plant Pathology Faculty Publications and Presentations

Anthropogenic salinization resulting from road salt application can degrade aquatic environments by altering the structure and function of phytoplankton communities, ultimately reducing flows of resources through aquatic food webs. However, physiological mechanisms underlying taxon-specific responses to salinization are often poorly linked to higher-order ecosystem dynamics, limiting our ability to predict community responses to salinization. To this end, we tested hypotheses derived from Subsidy-Stress and Ecological Stoichiometry theory by growing two cosmopolitan genera, Dolichospermum (prokaryotic, cyanobacteria) and Scenedesmus (eukaryotic, green algae), across NaCl gradients and contrasting differences in their growth rates, degree of Na homeostasis, and cellular C : N : …

Opa1-Mediated Mitochondrial Dynamics In Myogenic Differentiation Of C2c12 Myoblasts, Daniel Eloy Bazan

Theses and Dissertations

Mitochondria play a pivotal role in metabolic energy production, cellular signaling, and apoptosis. To carry out these key cellular roles, mitochondria dynamically balance their organization through opposing including fusion and fission processes. The balance between mitochondrial fusion and fission is regulated by key proteins such as OPA1 (optic atrophy 1) and OMA1 (overlapping activity with metalloprotease). More recently, mitochondria have been increasingly revealed to play key roles in cellular differentiation, where metabolic demands are reprogrammed. This study aims to elucidate the specific roles of OPA1 and OMA1 in the differentiation of C2C12 myoblast cells into myotubes.

Our data demonstrates that …

The Role Of Androgen Receptor And B2/Alu Sine Rna Interaction In Hippocampal Dendritic Development, Troy A. Richter

Graduate Doctoral Dissertations

Once dismissed as “junk”, transposable elements have recently gained recognition for their regulatory roles, especially in the brain. During development, circulating androgens promote proper morphological development of hippocampal neurons. We and others have shown that murine B2 SINE RNA is a regulator in the rodent hippocampus. It is unknown, however, if B2 is necessary for the proper development of hippocampal neurons. This dissertation investigates the role of murine B2 in the development of primary hippocampal neurons in combination with androgen treatment. We first examined the role of ALU SINE and androgen receptor in a prostate cancer cell model and found …

Commodity Diversification, Technological Innovation, And Market Dynamics: Insights Into Beef Cattle Production And Feeder Cattle Basis In The United States, Nik Berg

All Theses

The beef cattle industry plays an important role in the agricultural economy, contributing to both domestic food supply and global trade. The United States is one of the world's largest producers of beef, with production systems varying widely across regions largely due to differences in available resources and market structures. Market conditions, technological advancements, and policy interventions shape the way producers operate, making research into these factors essential for both industry stakeholders and policymakers.

Producers are continuously adapting to changing economic conditions, environmental challenges, and evolving consumer preferences. By analyzing these factors, researchers can provide insights to support informed decision-making …

Effect Of Amino Acid Derivatives And Polyphenol Supplementation On Skeletal Muscle Growth In-Vitro And In-Vivo, Gabriella C. Iheanacho

All Theses

Background

Satellite cells (SCs) are myogenic precursor cells that play a crucial role in muscle growth, and their activity can be influenced by nutrient supplementation. Muscle growth can also be stimulated using growth-promoting hormones; however, there are no approved growth hormones for use in sheep in the United States (Qaid & Abdoun, 2022). This limitation highlights a need to identify alternative compounds that would serve as nutrient supplements to enhance muscle growth and thereby improve meat production. Amino acid derivatives such as guanidinoacetic acid (GAA) and 5-hydroxytryptophan (5-HTP), along with the polyphenol quercetin, are naturally derived compounds that have shown …

Life Cycle Assessment Of The Cultivation Of Lettuce In A Hydroponic System Using The Nutrient Film Technique, Raquel Jordan

All Theses

Hydroponic systems are an emerging method of soilless crop cultivation typically done inside a greenhouse where nutrients are delivered dissolved in water rather than being supplied from the soil. Potential benefits of hydroponic systems include reduced irrigation requirements, higher crop yield per area, and the ability to grow crops year-round in nontraditional areas such as urban settings, cold climates, and sites with contaminated soil. However, hydroponic systems tend to have high energy requirements for lighting and climate control, which can yield significant environmental impacts. To explore the environmental impacts of cultivating lettuce in a nutrient film technique (NFT) hydroponic system, …

Ecological And Social Resilience In Wildfire-Prone Communities, Melissa Burnett

All Theses

Climate projections suggest extreme weather variability, introducing extremely wet years, followed by years with extreme drought. These weather conditions are creating fire weather conducive to increasing wildfires across the southeast over the next century, which can have extreme ecological consequences. The Appalachian Mountains historically had some of the highest fire frequencies in North America but have been subjected to decades of fire suppression and prevention policies, resulting in an environment subject to more high-severity wildfires. The fall of 2016 was one of the driest seasons on record in this region and resulted in intense and destructive fires in the southeastern …

Polyphenols For The Mitigation Of Vascular Calcification; In Vitro And In Vivo Studies, Abdullah Altuhami

All Theses

Globally, cardiovascular diseases, in most cases associated with calcification, are the main cause of death. However, currently, the only effective cure is to undergo surgery to augment or receive a healthy donor heart, which could be very difficult due to the long waiting list and the associated risks. The possibility of body rejection of the foreign organs is attributed to immunoreaction or the risk of infection, since the donor must be on immunosuppressant drugs that lower the body's immunity and facilitate the body's acceptance of the new organ as one of its own. Taking that into consideration, using tissue-engineered vascular …

Cultivation Of Botryococcus Braunii For The Production Of Hydrocarbons Suitable For Fuel Use, Bryan C. Carroll

All Theses

Energy security, rural poverty, and climate change are pressing issues of our time. Biofuels provide a solution to these issues, with a focus on sustainable aviation fuel, SAF, due to compatibility with aircraft infrastructure and energy density. This research aims to review and produce knowledge about a specific microalga, Botryococcus braunii, for its potential for SAF. First a literature review on the process was conducted followed by an experimental study on the impact of aqueous media and inorganic carbon its growth and hydrocarbon content. The literature review found the process consists of cultivation followed by lipid extraction or hydrothermal …

3,5-Dihydroxy-4-Isopropylstilbene (Tapinarof) Is A Partial Aryl Hydrocarbon Receptor Agonist In Fish, Conner A. Dicks

All Theses

The aryl hydrocarbon receptor (AHR) is a ligand activated transcription factor that is essential in regulating development, immune homeostasis, and drug and xenobiotic metabolism. Activation of the AHR by specific ligands results in its translocation to the nucleus where it induces a myriad of gene products, including cytochrome P450 (CYP) drug metabolizing enzymes (e.g., CYP1A1) and other components of the chemical defensome, as well as inflammatory control. Interestingly, the AHR can bind a wide variety of endogenous and xenobiotic ligands which are able to induce unique downstream effects dependent on cell type, inflammatory context, and ligand stability. The AHR is …

Using Livestreaming Technology To Answer Novel Questions About The Behavior And Physiological Ecology Of The Prairie Rattlesnake (Crotalus Viridis), Max C. Roberts

Master's Theses

Recent advances in remote monitoring technology are opening up new opportunities for developing innovative natural history and biological research methodologies. In particular, the emergence of livestreaming camera technology has made recording remote video of wild and secretive animals much easier and made it possible to collect data at extremely fine temporal resolutions. In 2024, Project RattleCam launched a livestreaming camera at a Prairie Rattlesnake (Crotalus viridis) den in Colorado. The goal of this work was to study Prairie Rattlesnake behavior 24-7 throughout the species’ active season with minimal human disturbance. Additionally, I used this system to study the …

Investigating Rattlesnake Social Networks And Improving Their Public Image Through Unobtrusive Technologies And Community Science, Owen M. Bachhuber

Master's Theses

While technology is often blamed for humans’ increasing disconnect with nature, it can also serve as a tool to facilitate empathy and conservation action for wildlife. Snakes are among the most feared animals on the planet, though their understudied social interactions provide opportunities to make scientific discoveries and change public perceptions. Project RattleCam was founded as a camera trap project in 2021 and launched the first off-grid livestream on a den of wild Prairie Rattlesnakes (Crotalus viridis) in 2024. Both camera types captured hundreds of Prairie Rattlesnakes gathering in the summer as they prepared to give birth to pups before …

Impact Of S-Phase Kinase Protien 2 Blockades On Hematopoetic Stem Cell Metabolism, Nicole Elmaraghy

Electronic Theses, Projects, and Dissertations

Hematopoietic stem and progenitor cells (HSPCs) quiescence is vital for the success of bone marrow transplantation, as it preserves long term self- renewal and prevents premature exhaustion (Takubo et al., 2013; Wilson et al., 2008). However, bone marrow transplant (BMT) failure remains a clinical challenge, often due to lack of long-term engraftment and insufficient stress reliance. Both of these characteristics are tightly linked to disrupted stem cell quiescence and metabolic imbalance (Anso et al., 2017; Vannini et al., 2016). One key player is S-phase kinase protein (SKP2), an E3 ubiquitin ligase that targets cell cycle inhibitors, like p27, for proteosome …

Multi-Crop Systems And Crop-Switching Strategies To Enhance Water Use Efficiency And Climate Resilience In Arid Agricultural Regions, Shahryar Fazli, Wenzhao Li, Surendra Maharjan, Hesham El-Askary

Mathematics, Physics, and Computer Science Faculty Articles and Research

Agriculture in the Lower Colorado River (LCR) region faces mounting challenges from climate change, arid conditions, and water scarcity. This study evaluates water use efficiency (WUEc) and crop-switching strategies under SSP2-4.5 and SSP5-8.5 scenarios for 2025–2049, 2050–2074, and 2075–2099. Using historical data, climatic drivers such as temperature and precipitation were analyzed for their influence on key crops, including durum wheat, winter wheat, and corn. Results show SSP2-4.5 supports water use reductions up to 16%, stable profits (80–90%), and modest calorie increases (up to 15%), while SSP5-8.5 poses severe challenges, with water use reductions of 2–5%, profits dropping to around 20%, …

Resolving Intra-Tumoral Heterogeneity Of Breast Cancer Using Single-Cell Multi-Omics, Yun Yan

Dissertations and Theses (Open Access)

Breast cancer is a highly heterogeneous disease characterized by diverse genetic, transcriptional, and epigenetic landscapes. Understanding how intra-tumoral heterogeneity (ITH) influences therapeutic response and drives tumor evolution remains a central challenge in cancer biology. Here, we leverage single-cell multi-omics technologies to dissect the cell states and gene expression programs underlying breast cancer heterogeneity, with a focus on triple-negative breast cancer (TNBC) and estrogen receptor-positive (ER+) breast cancer.

In the first part, we applied single-cell RNA sequencing and spatial transcriptomics to profile over 400,000 cells from 101 treatment-naïve TNBC patients. We identified 4 archetypes at the patient level and 13 metaprograms …

Predicting Genetic Interactions Using Functional Interaction Networks, Iulia Veronica Gheorghe

Dissertations and Theses (Open Access)

Mapping genetic interactions is central to understanding cellular systems and identifying therapeutic vulnerabilities, particularly in the context of cancer. Among these interactions, synthetic lethality, where simultaneous loss of two genes is lethal but loss of either alone is tolerated, offers a powerful framework for selectively targeting tumor-specific dependencies. In model organisms like S. cerevisiae, comprehensive double-knockout screens have revealed detailed genetic interaction maps, enabling systems-level insights into pathway structure, gene function, and cellular organization. Replicating this achievement in human cells, however, is complicated by the scale and complexity of the human genome. Recent advances in genome-wide CRISPR knockout screening have …

Investigating The Role Of The Lysine-Specific Demethylase 4c In Pancreatic Ductal Adenocarcinoma, Mennatallah Shaheen

Dissertations and Theses (Open Access)

Deregulation of proteins involved in chromatin regulation is common in pancreatic ductal adenocarcinoma (PDAC). Lysine demethylase 4C (KDM4C) is one of the chromatin modifying proteins frequently overexpressed across multiple solid cancers and is linked to chromatin instability, increased cell proliferation, and enhanced stem cell-like behavior. We observed upregulation of KDM4C protein in a panel of human PDAC cell lines and patient samples compared to non-neoplastic controls. CRISPR/Cas9-mediated deletion of KDM4C in human and murine PDAC cells reduced proliferation, clonogenicity, and increased survival of orthotopically implanted murine PDAC allografts. Transcriptomic and proteomics analyses revealed that loss of KDM4C in both human …

Long-Chain Fatty Acids Promote Candida Albicans Gut Colonization By Restructuring The Fungal Cell Surface, Musfirat Shubaita

Dissertations and Theses (Open Access)

Long-chain fatty acids promote Candida albicans gut colonization by restructuring the fungal cell surface

Musfirat Shubaita, BS

Advisory Professor: J. Christian Perez, Ph.D.

The yeast Candida albicans is a facultative anaerobe residing in the human digestive tract. Although fungal genetic determinants of mammalian host colonization have been identified, little is known about signals and molecules in the intestinal environment that influence C. albicans proliferation. Previously unpublished data from the Perez lab showed that oleic acid, one of the most abundant long-chain fatty acids in nature, promotes C. albicans colonization of the murine intestine. The goal of this research is to …

Studies Of The Mechanisms Of Reverse Signaling By Cd40l, Barbara M. Nassif Rausseo

Dissertations and Theses (Open Access)

CD40 ligand (CD40L) is a transmembrane protein expressed on activated CD4 T cells, traditionally known for its role in forward signaling by engaging CD40 on antigen- presenting cells to promote immune activation. While this pathway is well characterized, there is evidence that CD40L also mediates reverse signaling, acting as a signaling receptor on T cells which enhances T cell function. However, the extent, consequences, and mechanism of CD40L-mediated reverse signaling in CD4 T cells remain poorly defined. This dissertation investigates the mechanisms and effects of CD40L reverse signaling on T cell function using both primary human T cells and the …

Microbial Metabolite Regulation Of Microglial Ahr Signaling In Alzheimer’S Disease, Ghalya E. Alrousan

Dissertations and Theses (Open Access)

Introduction: Alzheimer’s disease (AD) is a progressive neurodegenerative disorder characterized by amyloid-β plaque accumulation, neuroinflammation, and cognitive decline. Recent evidence suggests that systemic factors, particularly the gut microbiota and its metabolites, play a significant role in shaping brain immune responses, including microglial activation. However, the mechanisms linking gut dysbiosis to microglial dysfunction in AD are poorly understood. The aryl hydrocarbon receptor (AHR), a ligand-activated transcription factor responsive to tryptophan metabolites, has recently gained attention as a key regulator of neuroinflammation and microglial function. I hypothesize that the loss of beneficial microbial AHR ligands, specifically indole derivatives, during aging and AD …

From Cities To Ranches: Assessing Public Support For Jaguar (Panthera Onca) Conservation And Livestock Predation In Colombia, Luz Angelica Solano

All Dissertations

Jaguars are among the most emblematic large carnivores worldwide. Nonetheless, the species has declined by 25% in less than 25 years and their range has been reduced by 55%, approximately, primarily due to habitat loss from increasing agricultural development, retaliatory killings from human-jaguar conflict, and overhunting of their natural prey. Given the anthropogenic nature of these threats, developing effective coexistence strategies and public support for jaguar conservation are increasingly urgent for the continued persistence of this species. I conducted a scoping review to assess trends and gaps in the existing peer-reviewed literature, grey literature, and news articles related to human-jaguar …

Interactions Of Biorational And Synthetic Dmi Fungicides For Control Of Fruit Diseases, Johanna Wesche

All Dissertations

Biological fungicides are increasingly investigated as sustainable alternatives to synthetic fungicides in fruit crop protection. This dissertation examines the interactions between two commercial biological fungicides, Bacillus subtilis AFS032321 (Theia) and metabolites of Pseudomonas chlororaphis AFS009 (Howler EVO); and demethylation inhibitor (DMI) fungicides, with a focus on compatibility, synergistic potential, and resistance implications. In vitro assays revealed that commonly used DMI fungicides difenoconazole, metconazole, tebuconazole, and propiconazole inhibited vegetative growth of B. subtilis at concentrations above 50 µg/ml, whereas mefentrifluconazole promoted colony expansion. Under controlled conditions, lesion development on detached fruit was inhibited synergistically when Theia was combined with the growth-promoting …

An Evaluation Of Key Components Of Natural Resource Camps, Undergraduate Persistence And Success In Natural Resources, Brandy Bishop

Electronic Theses and Dissertations

This study explores the key components that connect natural resource camps, undergraduate persistence, and overall success through gainful employment within the natural resource industry. The aim of this study was to assess early interest and attitudes towards natural resource career pathways and how education interventions shape students’ career outcomes thus leading to overall success. A longitudinal mixed method design was used combining Conservation Careers Camp survey data (n = 39) with institutional records for Forestry majors (n =655) in the Arthur Temple College of Forestry and Agriculture on the Stephen F. Austin State University campus. Quantitative data was analyzed through …

Authentication And Message Integrity Verification For Emerging Wireless Networks, Ebuka Philip Oguchi

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

This dissertation presents a comprehensive body of research on authentication and message integrity verification for emerging wireless networks, focusing on secret-free and physical layer security techniques across diverse, challenging, and unconventional environments.

It comprises four first-author contributions that span underground wireless systems, over-the-air (OTA) channels, vehicular communications, and nanoscale molecular networks.

The first contribution, Soil-Assisted Trust Establishment for Underground Wireless Networks (STUN), introduces a physical-layer trust bootstrapping protocol that achieves authentication and message integrity without pre-shared secrets. Leveraging underground-to-air propagation laws and trusted relay nodes, STUN resists active signal injection attacks and demonstrates security comparable to the unbalanced oil and …

Evolutionary Biomechanics In Cetartiodactyla: Impacts Of Ecological Shifts On Bone Material Properties And Control Surface Morphology, Danielle S. Adams

All Dissertations

Extreme ecological transitions expose organisms to novel selective pressures that can reshape morphology and performance. This dissertation investigates how the transition from land to water has influenced form and material properties in cetaceans (whales, dolphins, and porpoises), a clade that has undergone dramatic morphological and physiological adaptations to a fully aquatic lifestyle. I integrate comparative morphology, material property testing, and phylogenetic analyses, to explore how ecological demands, particularly related to foraging mode and prey detection, have shaped multiple aspects of cetacean morphology and function. Using nanoindentation and microCT, I measured elastic modulus and bone density of the skull and mandible …

A Convergent Mixed Methods Study Of The Social Studies Academy In South Carolina Middle Schools, Audie Cherry

All Dissertations

There is a global labor shortage in the agricultural industry and middle school is a critical time to get students serious about career decision making. The Studies of Occupations, Culture, and Innovations toward Agricultural Literacy (SOCIAL) Studies Academy is a high impact professional development program in South Carolina that provides experiences and for middle school social studies teachers (N = 12) to become more suited to teach their standards associated with the agricultural sciences with hopes of encouraging more students to pursue agricultural careers. This study was a mixed-methods convergent parallel design that examined 1) Academy Fellows (n = 4) …

Investigating The Multiple Enzyme Complex In The Carotenoid Biosynthesis Pathway, Mercy Mormor

Electronic Theses and Dissertations

In nature, plant carotenoids are 40-carbon isoprenoids with polyene chains that may have double bonds. They are vital components of all photosynthetic organisms, playing several roles in the plant cell, including photosynthesis, pigmentation, phytohormone synthesis, signaling and photoprotection. In this study, we investigated protein-protein interactions among key enzymes involved in the carotenoid biosynthesis pathway using the Bimolecular Fluorescent Complementation (BiFC) assay. Our results revealed several interactions that suggest a coordinated regulation of enzymatic activity within this pathway, highlighting potential regulatory complexes that influence carotenoid production. The study also highlights the pivotal role of Zeta-Carotene Isomerase (Z-ISO) as a key regulatory …

Drivers And Consequences Of Changes In Nectar Microbiome Composition Across Spatial And Biological Scales, Daniel A. Barker

Electronic Theses and Dissertations

Microbial communities inhabiting floral nectar, known as the nectar microbiome, are important mediators of plant-pollinator interactions. However, the ecological and environmental factors that shape the composition of these microbial communities remain poorly understood. While previous studies have examined the effects of a few microbial groups, typically independent of one another, on one plant or pollinator species, this dissertation takes a wide-scale approach to explore how abiotic conditions and biotic interaction’s structure microbial communities within floral nectar. Furthermore, I also quantify how variation in microbial richness and identity influences pollinator behavior and plant reproductive success.

This dissertation shows that microbial abundance …

Acquired Resistance In Cancer: Towards Targeted Therapeutic Strategies, Alice Soragni, Erik S Knudsen, Thomas N O'Connor, Cristina E Tognon, Jeffrey W Tyner, Beatrice Gini, Donghwa Kim, Trever G Bivona, Xingxing Zang, Agnieszka K Witkiewicz, David W Goodrich, Dadi Jiang, Seth T Gammon, Christopher D Willey, Paul C Boutros, Vlad C Sandulache, Abdullah A Osman, Jeffrey N Myers, Kamiya Mehla, Pankaj K Singh, Keith S Chan, Hongbo Gao, Himangi Marathe

Faculty, Staff and Student Publications

Development of acquired therapeutic resistance limits the efficacy of cancer treatments and accounts for therapeutic failure in most patients. How resistance arises, varies across cancer types and differs depending on therapeutic modalities is incompletely understood. Novel strategies that address and overcome the various and complex resistance mechanisms necessitate a deep understanding of the underlying dynamics. We are at a crucial time when innovative technologies applied to patient-relevant tumour models have the potential to bridge the gap between fundamental research into mechanisms and timing of acquired resistance and clinical applications that translate these findings into actionable strategies to extend therapy efficacy. …

Effect Of Moderate Decrease In Contractility On Epithelial Cell-Cell Contacts Under External Stretch, Saika Sharmin

Mechanical & Aerospace Engineering Theses & Dissertations

Epithelial tissues are characterized by extensive cell–cell contacts and often subject to stretch during normal function. Cell-cell contact adhesion strength maintains mechanical continuity from cell to cell. Mechanical forces exerted by cells via actomyosin contractility are known to strengthen cell-cell adhesions to a certain extent. While it is known that a large decrease in contractility causes cell-cell contact rupture due to weakened adhesions, it is unclear how a moderate reduction in contractility affects cell-cell junction stability. Here, we studied how a moderate inhibition of non-muscle myosin II (NMII) affects the integrity of epithelial cell-cell contacts, especially when subject to the …