Life Sciences Commons^™

Characterization Of Snrk1 Signaling In Rice Growth, Reproduction, And Stress Responses Using Phenotypic And Omics Analysis, Maria Clara Faria-Bates

Graduate Theses and Dissertations

SnRK1 is an evolutionarily conserved protein kinase belonging to the SNF1/AMPK family that is composed of a catalytic subunit (α) and two regulatory subunits (β and βγ), and it has a major role in adjusting growth in response to the energy status. SnRK1 phosphorylates and alters the activities of enzymes involved in metabolism and regulates gene expression by altering the activity of chromatin-remodeling enzymes or transcription factors. Rice contains three functional paralogs of SnRK1α: OsSnRK1αA (Os05g0530500), OsSnRK1αB (Os8g0484600), and OsSnRK1αC (Os03g0289100). Although SnRK1 is known to play a central role in plant growth and stress responses, the functional specialization of …

Bats And Bacteria: Infection Dynamics At The Human-Wildlife Interface, Isabella Katherine Deanglis

Graduate Theses and Dissertations

As the second most diverse mammalian order, bats host an array of pathogens, some of which are known to infect humans. Synanthropic bats share spaces with humans, resulting in bat-borne pathogen exposure. While most bat-borne disease research has focused on viral pathogens, bats host numerous bacterial pathogens with zoonotic potential. By integrating a global meta-analysis with field studies in Sub-Saharan Africa, I characterize the structural attributes that facilitate shared interfaces, the bacterial pathogens present in synanthropic bats of rural Kenya, and the physiological and environmental dynamics influencing odds of infection in these synanthropic bats. Finally, I evaluate the clinical relevance …

A Survey Of The Collembola Of The Buffalo National River Park, Emma Renee Critchfield

Graduate Theses and Dissertations

Collembola are a neglected and understudied class with few recent U.S surveys. The aim of this thesis was to survey the Buffalo National River for Collembola and create a catalogue of all known species in the state of Arkansas, USA. Leaf litter, mosses, rotting wood, fungi and malaise trap samples were taken from 13 locations within the Buffalo National River park. In total, 14 families, 34 genera and 59 species were identified from 22,028 collected specimens. Of those, 31 species represent new state records. This survey also validates malaise traps as useful tools for Collembola sampling. The malaise trap samples, …

Unveiling Factors Influencing Extract Yield From Milled Rice In Brewing, Matthew Aitkens

Graduate Theses and Dissertations

Rice (Oryza sativa L.) presents a locally sourced, climate-resistant starch source for the brewing industry. As barley faces increased uncertainty due to rising temperatures, Arkansas-grown rice offers a more stable and cost-effective alternative starch source. However, the use of milled adjunct rice by brewers has remained limited, largely due to knowledge gaps about cultivar-specific properties relative to brewing. Chapter 1 provides an overview of rice as a brewing adjunct, reviewing the physiochemical properties important to brewing success. These properties include kernel size, kernel breakage, amylose content, and gelatinization temperature. Mashing strategies for multiple different brewing layouts are overviewed, showing practical …

Validation Of Rice Tissue Sampling For In-Season Nutrient Management Of Nitrogen, Phosphorus, And Potassium, Tanner Smith

Graduate Theses and Dissertations

Nitrogen (N), phosphorus (P), and potassium (K) are the 3 most important nutrients involved in rice (Oryza sativa L.) growth and development. Tissue sampling has been proven to be a potential tool to provide inseason information about plant nutrient concentrations at specified timings and growth stages. With increased interest in tissue sampling and improving nutrient management effectiveness, more information is needed to validate plant tissue concentrations at which additional fertilizer inputs may be warranted. Experiments were conducted in 2024 and 2025 at the Rice Research and Extension Center (RREC) near Stuttgart, Ark.; Pine Tree Research Station (PTRS) near Colt, Ark.; …

Lumbopelvic Kinematics And Muscular Co-Contractions In Walking Prior To And Immediately Following A Bout Of Prolonged Standing., Stephanie Cotariu

Graduate Theses and Dissertations

Background: Prolonged standing is a common daily activity in a wide array of occupations, and approximately 44% of sample populations develop low back pain (LBP) during prolonged standing. Prolonged standing-induced LBP developers (“Pain Developers”) are three times more likely to develop clinical LBP and can therefore be considered a pre-clinical LBP population. Changes in typical gait have been observed in LBP patients, and walking has been hypothesized as being protective or preventive against LBP development. However, it is unknown whether Pain Developers exhibit similar kinematic adaptations to chronic LBP patients during common daily activities, such as walking. The exact muscular …

Assessment Of The Quality, Practicality, And Economic Viability Of Malted Rice, Bernardo Pontes Guimaraes

Graduate Theses and Dissertations

Climate change threatens the global supply of malting barley, creating a need for sustainable, climate-resilient alternative grains for the brewing industries. This dissertation investigated the chemical, sensorial, practical, and economic viability of using rice as a malting material. First, the malting and brewing qualities of 20 rice samples were evaluated. Results indicated malted rice (MR) had good malting and brewing qualities, including adequate levels of free amino nitrogen (FAN), high amyloglucosidase and limit dextrinase activities. Furthermore, pigmented rice varieties displayed a novel reddish-purple wort color. To identify rice cultivars suited for malting and brewing, the relationship between starch chemistry and …

Descriptive Comparative Analysis Of Bacteriophage And Auxiliary Metabolic Gene Diversity In Marine And Wastewater Environments, Andrew Crawford

Undergraduate University Honors Capstones

Bacteriophages (phages) are viruses that infect bacteria and play a role in bacterial evolution. Through horizontal gene transfer (HGT), phages integrate parts of their genomes into their bacterial hosts. While the molecular mechanisms of this process are well understood, the evolutionary impacts remain less certain. One evolutionary explanation is that auxiliary metabolic genes (AMGs) modulate host gene expression to favor phage reproduction or improve the host’s survival. AMG can persist in hosts' or phages' genomes across future generations, altering their contributions to the ecosystem and posing a concern for human and environmental health. The objective of this project is to …

Twenty-Four-Hour Intermittent Fasting Extends Lifespan At The Expense Of Fecundity In Daphnia, Meridith L. Smith

Undergraduate Honors Theses

Dietary restriction (DR) is a well-established intervention for extending lifespan, yet the specific efficacy of intermittent fasting (IF) and its associated trade-offs remain under-explored in many Daphnia magna. This study investigated the effects of three IF intervals—2h, 24h, and 48h—on the longevity and fecundity of two clones of Daphnia. We hypothesized that longer fasting intervals would significantly extend lifespan at the cost of reproductive output, consistent with the disposable soma theory of resource allocation.
Our results demonstrate that 24h IF significantly increased longevity relative to ad libitum controls, even outperforming caloric restriction (CR) by reducing late-life mortality. In …

Molecular Mechanisms Of Pfas Induced Protein Dysfunction: Implications For Neurodegenerative Risk, Daisy Lee Wilson

Open Access Theses & Dissertations

Per- and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants with widespread human exposure and well-established links to adverse health outcomes. However, despite increasing epidemiological and experimental evidence, the molecular mechanisms underlying PFAS-induced neurotoxicity remain incompletely defined. This dissertation investigates PFAS toxicity across biological scales, integrating protein biophysics with neuronal cell models to elucidate pathways relevant to neurodegeneration. At the molecular level, we demonstrate that PFAS disrupts the structure and function of globular proteins, including the impairment of α-lactalbumin's calcium-binding capacity and of β-lactoglobulin's retinol binding, through concentration-dependent conformational destabilization. By applying these findings to a neuronal model, we show that …

Mitogenomic And Physiological Comparison Between Wild And Domesticated Congeners, Nicholas Enriquez

Open Access Theses & Dissertations

Domestication is a process in which wild populations are morphologically and/or behaviorally manipulated through selective breeding to become optimized for living in captivity. Consequently, many traits become quickly and significantly diverged from their ancestral, wild lineages, a process known as part of domestication syndrome. Captive breeding of mallards (Anas platyrhynchos) was one of the last major successful domestication events resulting in dozens of recognized breeds today. Many breeds were optimized for either ornamental or agricultural purposes (i.e., meat and/or egg production), but the game-farm mallard was specifically bred for sport hunting. In North America, the use of game-farm mallards to …

Prediabetes Prediction Before Disease Onset Using Multimodal Health Data: A Machine Learning Approach, Luisa Veronica Gracia Mazuca

Open Access Theses & Dissertations

Prediabetes is a critical health condition that increases the risk of developing type 2 diabetes. The hemoglobin A1c (HbA1c) test diagnoses patients with prediabetes, but the disease has already caused metabolic alterations. Early detection is essential for timely interventions, and machine learning models offer a promising approach to identify prediabetic individuals through the analysis of biomarkers such as cytokines. We compared four classifiers-logistic regression, decision tree, random forest, and k-nearest neighbors - using cytokines (TNF-α, MCP-1, IL-1β, IL-6, IFN-γ), age, BMI, and waist-to-hip ratio (WHR). Models were evaluated using stratified 5-fold cross-validation and ROC-AUC. K-Nearest Neighbors (k-NN) achieved the highest …

Development Of A High-Throughput Framework For Studying Choice-Movement Dynamics In Freely Moving Rats Across Motivational And Pharmacological States, Atanu Giri

Open Access Theses & Dissertations

This thesis develops and applies high-throughput behavioral assays and analysis pipelines to study how external contingencies and internal state shape rodent decision-making. First, it introduces RECORD (Reward-Cost in Rodent Decision-making), a modular platform that combines 3D-printed arenas, microcontroller-based control, and closed-loop trial structure to deliver graded rewards and costs in a foraging-like environment. RECORD supports scalable data collection across multiple arenas and a software stack for parsing, databasing, and extracting spatiotemporal behavioral features and psychometric choice functions. Using this framework, the thesis quantifies how animals integrate sucrose reward magnitude with aversive light cost, revealing structured individual differences and sex-dependent movement …

Design And Optimization Of Peptide Inhibitors Targeting Kinesin: Molecular Modeling Studies And Virtual Screening For Therapeutic Candidate Development, Maraf Mbah Bake

Open Access Theses & Dissertations

Kinesins are ATP-driven molecular motors essential for intracellular transport and mitotic spindle assembly, and their mechanochemical behavior has been extensively characterized through computational tools. The first project reviews decades of advances in molecular dynamic simulations, including all-atom and coarse-grained molecular dynamics, Markov state models, Brownian dynamics, and free-energy approaches, which have collectively deepened our understanding of conformational transitions, microtubule-binding interfaces, and ligand interactions, especially for the mitotic motor Eg5. The second review examines the rapid emergence of quantum computing as a transformative technology for drug discovery, highlighting key historical milestones, recent progress in hybrid quantum-classical algorithms, quantum-enhanced docking, and quantum …

Mapping The Lateral Hypothalamic Area: Chemoarchitecture, Connectivity, And Activation In Motivated Learning And Reward, Vanessa Inez Navarro

Open Access Theses & Dissertations

The lateral hypothalamic area (LHA) is a large and complex hypothalamic region with diverse functions across four main rostrocaudal divisions. Despite its size and diversity, disagreements over how to define LHA subdivisions (e.g., Swanson atlas lists 17 subdivisions) make it challenging to fully characterize its structure and function. Across these subregions, neuronal connectivity varies, indicating they serve different behavioral functions. Consistent with this, particular LHA neuronal pathways have been linked to reward-related responses, emphasizing the region's roles in motivation, feeding, and cognition. Current approaches to classifying the LHA have primarily relied on neurochemical markers or gene-directed manipulations, often without integrating …

High-Resolution Mapping Of Brainstem Feeding Circuits: A Framework For Targeted Neuroscience Tools, Geronimo Tapia

Open Access Theses & Dissertations

The neural control of energy balance is mediated in part by distributed brainstem circuits that integrate metabolic, visceral, and hormonal signals to coordinate appropriate motivated behaviors and autonomic responses. Despite extensive study, the precise neuroanatomical architecture regulating metabolism remains incompletely defined within standardized atlas frameworks. This work addresses that gap through complementary studies examining an acute glycemic challenge methodology known to stimulate feeding, the acute delivery of an anorexigenic-associated neurohormone, and the chemoarchitecture of a major feeding-related region, the parabrachial nucleus. First, utilizing 2-deoxy-D-glucose (2-DG) induced glucoprivation, we map the rapid response of dorsal medullary neuronal populations with high spatial …

Determining Zap-70 Signaling Pathways Mediated By Ccr7 In Tcr T Cell Activation, Vivian Torres

Open Access Theses & Dissertations

Activation of T lymphocytes is the main event that occurs in the adaptive immune response after engagement of the T cell receptor (TCR) with the peptide of the major histocompatibility complex (pMHC) molecules that are demonstrated by antigen presenting cells [1]. A key step in this process is the recruitment and activation of the zeta chain associated protein of 70 kDa (ZAP-70). ZAP-70 couples TCR engagement to downstream intracellular signaling pathways through phosphorylation of tyrosine residues within intracellular tyrosine activation motifs (ITAMs) [2]. Although there have been extensive studies on the signaling response through TCR activation, the regulatory influence of …

From Soils To Plants And Back Again: The Effects Of Small Mammals On Arctic Ecosystem Processes, Andrew Uccello

Open Access Theses & Dissertations

Herbivores are essential drivers of above and belowground processes in ecosystems across the globe. Through their effects on ecosystem processes, herbivores represent a critical force shaping ecosystems undergoing rapid environmental changes, such as the Arctic. However, there are critical gaps in our knowledge of herbivores as drivers of Arctic ecosystem processes, especially concerning the role of small mammal herbivores. While previous research has made significant strides in identifying the role of small mammal herbivores as both top down and bottom up forces in Arctic ecosystems, we still lack an understanding that explicitly connects plant and soil responses to herbivory, especially …

Soil Microbial Responses To Artifical Light At Night, Randall L. Walker

Open Access Theses & Dissertations

Global change, driven by both natural processes and human activities, has significantly transformed ecosystems. Urbanization and artificial light at night (ALAN) are key contributors, disrupting natural light cycles and influencing biological rhythms, biodiversity, and ecosystem functions. Thus far, there remains a gap in knowledge of how soil ecosystems are impacted by ALAN. This study uses a laboratory incubation to investigate the effects of ALAN on soil microbial communities and functions across urban and natural ecosystems. Briefly, soil was collected from eight sites around El Paso, Texas and neighboring New Mexico representing urban and rural light exposure. Soil was then subjected …

The Impact Of High-Cadence Cycling On Overground Running Performance In Recreational Runners, Matthew Ott

Master's Theses

Cycling is a commonly used exercise because it provides a controllable cardiovascular and musculoskeletal demand while imposing relatively low impact on the rider. High-cadence cycling (HCC) has been shown to influence subsequent running performance and gait performance by increasing cadence and reducing work rate when cycling prior to running. However, most of this work has focused on triathletes and older adults. Therefore, the purpose of this study was to examine the acute effects of HCC on subsequent 800 m running performance and spatiotemporal parameters in adult recreational runners. Thirty recreational runners completed two testing sessions. On Day 1, participants performed …

Redeveloping Mississippi: A Case Study On Brownfields In Central & Southern Mississippi, Sahrah R. Yeroozedek

Master's Theses

Brownfields, or properties that are or possibly are contaminated with dangerous materials, represent a common obstacle for communities in Mississippi. The real or potential presence of contaminants at these sites often deters investors due to costly cleanup requirements (EPA, n.d. -b). The Environmental Protection Agency (EPA), through its Brownfield Revitalization Program, implemented guidelines for covering the costs and labor associated with the remediation of these properties. The EPA is not, however, responsible for redevelopment that supports long-term environmental and economic sustainability. Although the EPA maintains inventories of all Brownfields, there is also no comprehensive database of Brownfields and their current …

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 …

Dirty Defense: Investigating The Defensive Function Of Fecal Egg Cases In The Dogbane Beetle (Chrysochus Auratus), Alexandra Miller

Undergraduate Theses and Capstone Projects

Defecation is the elimination of digestive waste by animals. In insects, these wastes are composed of both undigested food and nitrogenous wastes in the form of uric acid, and can be either liquid or solid form as they exit the anus (Weiss, 2006). Food is ingested, ground, and some of it is stored in the foregut of the insect while the midgut digests food chemically and absorbs nutrients. What remains after the foregut and midgut is then moved into the hindgut, where they accumulate with uric acid coming from the malpighian tubules (Weiss, 2006). According to Weiss (2006), rectal pads …

The Effect Of Rider Balance On Equine Heart Rate During Therapeutic Riding, Lydia R. Nelson

Undergraduate Theses and Capstone Projects

Therapeutic riding provides emotional and physical benefits for riders who have disabilities, yet the physical demands placed on equines in therapeutic riding are not fully understood. Equestrian imbalance is a common characteristic in therapeutic riding, which may increase the workload on the equine. This study aims to evaluate whether induced rider imbalance increases equine heart rate, indicating greater workload, in comparison to riding with a balanced equestrian. One therapeutic riding equine and one experienced equestrian from Brook Hill Farm participated in this study. Heart rate (HR) data were collected with a heart rate monitor strapped around the equine for 21 …

Investigating Arginase Activity In The Murine Macrophage Raw 264.7 Cell Line, Abigail G. Johnson

Undergraduate Theses and Capstone Projects

Macrophages are a type of white blood cell that have important functional roles in the innate immune system, the body’s first line of defense against invading pathogens. Macrophages possess two phenotypic forms, M1 and M2, which are functionally and metabolically different and respond to different stimuli. M1 macrophages respond to bacterial products, such as lipopolysaccharide (LPS), by producing pro-inflammatory mediators. Furthermore, M2 macrophages respond to 8 Bromo cAMP (8Br) by producing tissue repair and wound healing properties. Second messenger signaling through cAMP plays an important role in the resolution of inflammation and inflammatory mediators. Metabolism plays a key role in …

Donor And Recipient Microbiome Interactions Determine Functional Outcomes Of Fecal Microbiota Transplantation For Clostridioides Difficile Infection, Sophie A. Millard

All Dissertations

Clostridioides difficile is a major cause of healthcare-associated diarrhea. Infection typically occurs after antibiotic treatment disrupts the gut microbiome, allowing C. difficile to colonize and produce toxins leading to disease (CDI). Standard antibiotic treatments can resolve acute infection but frequently lead to recurrence, highlighting the need for alternative strategies that restore the gut ecosystem. Fecal microbiota transplantation (FMT), the transfer of stool from a healthy donor, has emerged as an effective therapy for recurrent C. difficile infection (rCDI). Understanding the mechanisms underlying the success of FMT for treatment of rCDI could lead to safer, more defined microbial mixtures.

This dissertation …

High Throughput Phenomics Pipeline For Pulse Crop Nutritional Breeding, Amod Udayanga Madurapperumage

All Dissertations

Dry pea (Pisum sativum L.), lentil (Lens culinaris Medik.), and chickpea (Cicer arietinum L.) are major pulse crops valued for their high nutritional composition and importance to global food systems. Pulses are rich in carbohydrates, protein, and essential minerals, making them ideal whole foods and critical contributors to food and nutrition security. Due to these advantages, pulse breeding programs are increasingly focusing on enhancing nutritional traits, such as protein quality, amino acid balance, and micronutrient density, through the process of biofortification. However, improvement of agronomic traits remains equally essential. Characteristics such as plant height, standability, stress tolerance, …

Integrating Incentive Design And Spatial Prioritization For Climate-Smart Forestry Adoption In South Carolina, United States, Miah Maye Pormon

All Dissertations

Forests provide essential ecosystem services, including carbon sequestration, water regulation, timber production, and habitat provision. However, increasing development pressures and land-use changes threaten forest persistence and long-run ecosystem service provision. Climate-smart forestry (CSF) practices, such as improved forest management and extended rotation, offer opportunities to enhance carbon storage, forest resilience, and economic livelihoods. The effectiveness of these practices depends on forest owners’ participation and the strategic allocation of financial resources or incentives. This dissertation develops an integrated framework that combines behavioral economic analysis and mapping to improve the design of current incentive programs. The first chapter employs the Contingent Valuation …

Effects Of Tourist Feeding On The Gut Microbiome And Ecophysiology Of Endangered Northern Bahamian Rock Iguana (Cyclura Cychlura), Erin Lucy Lewis

All Graduate Theses and Dissertations, Fall 2023 to Present

The lifespan and reproduction of an animal depends on maintaining a healthy physiology. The proportion of individuals that survive to an age at which procreation can occur is important to long-term stability of populations and contributes to species survival. Health in an animal is measured in a variety of ways, including through monitoring of the body’s physiological systems, as well as its ability to respond to invading pathogens, and through the different types of bacteria present in the gut. Relationships among those different health metrics have been discovered in recent years and have been found to play important roles in …