Life Sciences Commons^™

Metabolic Regulation Of Cardiac Fibroblast Phenotype And Function., Collin Kleis Wells

Electronic Theses and Dissertations

Cardiac fibroblasts are central effectors of cardiac repair after myocardial infarction (MI). In response to signaling cues, they differentiate to a range of phenotypes with robust capacities to synthesize and secrete extracellular matrix (ECM) and signaling molecules. Although activated fibroblast phenotypes are associated with pronounced changes in metabolism, it remains unclear how the metabolic network upholds the effector functions of fibroblasts in the post-infarcted heart. Here, we identified that critical enzymes in the phosphoenolpyruvate (PEP) cycle, i.e. pyruvate kinase muscle-2 (PKM2) and phosphoenolpyruvate carboxykinase-2 (PCK2), are elevated in the heart after MI and examined their role in regulating post-MI remodeling …

Genes That Matter: Survival Modeling In Tcga-Brca With Treatment Interactions., David Pratt

Electronic Theses and Dissertations

High-dimensional genomic data offer both promise and challenges for identifying clinically relevant biomarkers. This study developed a parallelized survival modeling pipeline to identify genes associated with overall survival in breast cancer, with a focus on gene-by-treatment interactions and patient heterogeneity. RNA-Seq data from female patients in the TCGA-BRCA cohort were analyzed. Univariate Cox proportional hazards models were used to screen genes, adjusting for age, race/ethnicity, treatment status, and cancer stage. A LASSO-penalized Cox regression was fit across 2000 random seeds to assess feature stability. Genes were filtered by expression level, statistical significance, and hazard ratios (effect sizes) in either direction, …

Raptors As Secondary Dispersers Of Mycorrhizal Fungal Spores, Joseph Anderson

Electronic Theses and Dissertations

Animals aid fungal dispersal by consuming fruiting bodies (e.g., truffles) and depositing spores elsewhere. Predators can act as secondary dispersers by preying on small mammals that eat truffles, although it is unclear how this dispersal may vary among species of raptors (hawks and owls) and fungal taxa. We experimentally fed four truffle taxa (with spores varying in size and wall thickness) to six raptor species (with differing gut morphology and acidity) to assess how spore viability and retention time may change between raptor casts and feces. Viability in smaller spores was more negatively affected by acidity compared to larger spores …

Coastal Transition Zone Development Effects On Salt Marsh Ecology, Amanda Mei Pysher

Electronic Theses and Dissertations

The coastal transition zone (CTZ) is a regional gradient linking terrestrial and marine systems, comprising of the terrestrial upland, the marsh-upland ecotone, and estuarine salt marshes. Along all US coastlines, including the South Carolina (SC) coast from Little River to Georgetown, increases in anthropogenic development of terrestrial uplands have altered the historically established vegetation, and various physical, chemical, biological, and geological gradients. Despite the CTZ's ecological importance, the trickle-down effects of terrestrial upland development on associated high marsh habitats remain understudied. Data were collected from developed (DEV) and undeveloped (UND) shorelines across three SC estuarine inlets. Multilevel modeling (MLM) was …

Site Fidelity, Seasonality, Movement, And Fish Associates Of Sand Tigers Carcharias Taurus In North Carolina, Ara L. Mcclanahan

Electronic Theses and Dissertations

Sand tigers Carcharias taurus are mackerel sharks with a disjunct global distribution in tropical and temperate seas. In the northwest Atlantic, sand tigers migrate along the coast of the eastern United States from the Gulf of Maine to Florida and occupy structurally complex benthic habitats. The long-term, underwater camera installation, SharkCam, at Frying Pan Tower, off Cape Fear, North Carolina, USA, sits atop an expanse of hard bottom reef frequented by sand tigers. The citizen-science platform Spot A Shark USA (SAS USA) uses images of sand tigers to identify and track individuals. This study utilized image encounters from SAS USA …

Analysis Of An Ethanol Sensitive Bmp-Nkx2.3-Fgf Signaling Pathway In Pouch Morphogenesis., Hieu Dai Le Vo

Electronic Theses and Dissertations

Craniofacial malformations lie at the heart of Fetal Alcohol Spectrum Disorders (FASD). While there is growing evidence for a genetic component to FASD, little is known of the cellular mechanisms underlying these ethanol-sensitive loci in facial development. Bone Morphogenetic Protein (Bmp) signaling pathway dependent pouch formation is a key mechanism in facial development. We have previously shown that multiple Bmp mutants are sensitized to ethanol-induced facial defects. However, ethanol does not directly impact Bmp signaling. This suggests that downstream effectors, like nkx2.3 and Fibroblast Growth Factor (Fgf) signaling, may mediate the impact of ethanol on Bmp mutants. Here, I …

Evaluating Alpha Spending Functions Applied To Observational Time-To-Event Analysis, Moses Torgbenu

Electronic Theses and Dissertations

This thesis explores the theoretical foundation of the alpha spending approach and extends its application beyond the conventional setting of randomized controlled trials (RCTs) to observational studies with time to event analyses. In these less structured environments, key design parameters such as the total number of events are often unknown, posing challenges for the standard implementation of sequential analysis methods.

Through simulation studies, this research delivers several important contributions. First, it presents a modified approach that uses calendar time to define the timing of interim analyses while relying on event-based information to estimate the correlation among test statistics. This adjustment …

Role Of Cellular Proteins In The Regulation Of Herpes Simplex Virus Type 1 Gene Expression And Dna Replication, Joseph R. Heath

Electronic Theses and Dissertations

Herpes simplex virus type 1 (HSV-1) is a ubiquitous human pathogen that infects the majority of the human population. To facilitate infection, this virus relies on a combination of host and viral factors. Previous studies have revealed a number of host proteins that associate with the HSV-1 genome throughout infection but their putative role(s) in this process remain undefined. This study aims to examine two such proteins to determine their contributions to HSV-1 gene expression and DNA replication. The first of these factors is Ints3, a subunit of the Integrator complex. This protein complex functions in transcription regulation, and Ints3 …

Gut Passage Time In Small Mammals: Influences Of Small Mammal Traits, Digesta Phase, And Particle Morphology, Noah G. Hale

Electronic Theses and Dissertations

Dispersal is crucial in maintaining healthy ecosystems, but little is known about mechanisms influencing fungal spore dispersal by animals. We aimed to develop a more mechanistic understanding of the influence of fungal spore traits and small mammal traits on gut retention time. We fed three species of small mammals (shrew, mouse, vole), which differ in gut morphologies, digestive strategies, and activity a combination of markers including: liquid digesta phase (CrEDTA), small particle (fungal spores with diverse morphologies), and large particles (glitter and beads, representing plant cells and seeds, respectively). We found that hindgut fermenters selectively retained the liquid markers, spores …

Mixture Effects On Metal Accumulation In The Asian Clam, Corbicula Fluminea, Mark A. Huff

Electronic Theses and Dissertations

Field collected Corbicula fluminea were exposed to trace level copper, lead, and zinc with the aim of examining the preferential accumulation between the soft tissue and shell. Metal levels were based on those in a permitted industrial effluent. At 1X effluent and 2X effluent exposure levels, copper was found to preferentially accumulate in the clam soft tissue, lead was found to preferentially accumulate in the clam shell, and zinc was found to excrete back into the diluent after preferentially accumulating in the clam soft tissue. When exposed as a mixture at 1X effluent levels, copper and lead were found to …

Evaluation Of A Forest Restoration Strategy On Small Mammals In Southern Pine Ecosystems, Gage R. Grantham, Jessica L. Glasscock, Christopher M. Schalk, Kathryn R. Kiid, Reuber Antoniazzi

Electronic Theses and Dissertations

Industrial forestry replanted historic native pine forests (e.g., longleaf pine [Pinus palustris] and shortleaf pine [Pinus echinata]) to homogenous, high-density plantations consisting of native off-site species (e.g., loblolly pine [Pinus taeda]) after intensive harvesting for wood products. The contemporary forest structure that remains, consisting of off-site overstory compositions, can potentially serve as an ecological bridge to facilitate a gradual transition to a more desirable canopy species, thereby conserving biodiversity and ecosystem function. Understanding disturbance-sensitive small mammal communities from restoration strategies (retention) can help achieve long-term management goals for ecosystem conservation across larger scales. I …

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 …

Stand Strucuture Of Planted Stands In Storm-Water Retention Basins, Jason Lanza

Electronic Theses and Dissertations

Trees assist in stormwater retention basin functionality as efficient sources of water removal, and determining stand structure and leaf area of forests can be a measure of their effectiveness. The structure of forest stands on these basins managed for runoff mitigation has received little attention. We investigated the structure and species composition/diversity (tree and herbaceous) of planted, managed stands and naturally regenerated stands on stormwater retention basins managed by Harris County Flood Control District in Harris County, Texas. We determined stand structure variables (trees per hectare, basal area per hectare, quadratic mean diameter, relative density, average tree height, and percent …

Changing Globally, Acting Locally: Responses Of Coastal Plant Functional Traits To Global Change Are Mediated By Biotic And Abiotic Interactions., Shannon L. Walker

Electronic Theses and Dissertations

We live in a time of rapid global change with substantial consequences for planet-wide functioning. Local ecosystems reflect this change, yet we struggle to predict their responses. Coastal ecosystems, like dune and interdunal wetlands, have declined rapidly and predicting their responses to global change is essential for future management. Functional traits may be particularly informative as they drive species and ecosystem responses and can provide generalizable findings. This dissertation investigates how global change, especially anthropogenic nitrogen (N) enrichment, interacts with abiotic and biotic factors to affect coastal sand dune and interdunal wetland plant functional traits. First, I used a long-term …

Ecosystem Services Of Urban Green Spaces In Louisville, Ky., Julia Kachanova

Electronic Theses and Dissertations

Accelerating urbanization poses critical challenges to urban green spaces (UGS), vital for ecological balance and human health. Rapid development often results in fragmented habitats, biodiversity loss, and diminished ecosystem service delivery. There is an urgent need to explore and evaluate novel strategies capable of enhancing urban resilience, such as implementing urban orchards, and managing existing parks and gardens in sustainable ways. This dissertation explores how different forms of urban green spaces (UGS) contribute to the provision and maintenance of critical ecosystem services that support human well-being and urban biodiversity. By analyzing UGS impact on ecosystem service provisioning and long-term sustainability, …

Linked Lives In The Riverbed: Integrating Fish Host Dynamics, Community Structure, And Demography For Freshwater Mussel Conservation., Jonathan Patrick Frommeyer

Electronic Theses and Dissertations

Freshwater mussels are long-lived benthic invertebrates that play key roles in nutrient cycling, water filtration, and habitat stability in rivers and streams. Despite their ecological importance, they are among the most imperiled faunal groups in North America, with their persistence increasingly threatened by environmental degradation and disruptions to host–parasite dynamics. This dissertation integrates host ecology, community structure, and demographic modeling to assess population viability and guide conservation priorities for mussel species in Kentucky river systems. The first chapter introduces the ecological context and conservation urgency surrounding freshwater mussels. In particular, emphasizing the need for multi-scale approaches to understand how parasitic …

The Influence Of Psychological, Biological, And Social Determinants On Disordered Eating Behaviors Among U.S. Young Adults: Evidence From Nhanes 2015-2018., Samantha Kaye Gerbine

Electronic Theses and Dissertations

Disordered eating behaviors (DEBs) are influenced by biological, social, and psychological factors, yet research often narrowly focuses on White, college-aged women. This study assessed the predictors and prevalence of DEBs in a nationally representative sample of U.S. young adults using data from the 2015–2018 National Health and Nutrition Examination Survey (NHANES). Survey weights were applied to generate national estimates. Descriptive statistics characterized the sample, and logistic regressions tested biological, social, and psychological predictors of DEBs. A composite risk score was developed using variables retained in the final model. The unweighted sample (n = 1,062) represented 64 million U.S. young adults. …

Evaluating Quadrupedal Locomotion In Bats: A Geometric Morphometric Comparison Of Vertebral Adaptations Across Mammals, Jessica Upham

Electronic Theses and Dissertations

Flight is the primary locomotion of bats, while quadrupedal locomotion is not often observed and is widely variable among bats. Frugivorous bats in Pteropodidae are more efficient climbers than frugivorous bats in Phyllostomidae and insectivorous bats in Vespertilionidae, while phyllostomids and vespertilionids are better at walking on horizontal surfaces. The aim of this study is to investigate whether bats with differing modes of nonflight locomotion also exhibit disparity in thoracolumbar vertebral morphology. Using geometric morphometrics, we compared the thoracolumbar vertebral shapes of these bat families with other terrestrial and arboreal mammals. The results revealed distinct vertebral shapes among bat families …

Cattle Regenerative Grazing Effects On Bat Activity In Southern Appalachia, Seth Morelock

Electronic Theses and Dissertations

Livestock farming accounts for about 70% of agricultural activity, with continuous grazing as the dominant conventional practice. However, this method often degrades biodiversity and ecosystem health through overgrazing. Regenerative grazing practices offer a potential ecologically sustainable approach to cattle management. Insectivorous bats are known to use agroecosystems for foraging and roosting habitats, offering an opportunity to assess their response to regenerative grazing. Using passive acoustic monitors, we evaluated the response of bats to cattle within regenerative grazed farms in East Tennessee, USA. Overall bat activity declined when cattle entered and exited paddocks, except for the tri-colored bat (Perimyotis subflavus …

The Effects Of Off-Season Evidence-Based Training Block Periodization Program On The Performance Of Soccer Athletes In A Di School: An Exploratory Study, Ibrahim F. Almughathawi

Electronic Theses and Dissertations

The investigators explored the effects of a two-year evidence-based block periodization strength training program on performance outcomes in NCAA Division I male soccer athletes. The investigators aimed to examine longitudinal changes in body composition, explosive strength, and match-play physical demands, as well as the associations between field-based performance assessment and GPS-derived metrics. Using a retrospective design, data were drawn from a research data repository for athletes who participated in a long-term sport science monitoring program under the same head coach and training conditions. Performance measures included vertical jump assessments (static and counter movement jumps under bodyweight and external load), isometric …

Investigating The Impact Of Psychoactive Plant Alkaloids On Bumblebee Behavior, Skylar Mathieson

Electronic Theses and Dissertations

The relationship between plants and their pollinators is often framed as a food-for-service exchange in which plants provide pollinators with nutrients in exchange for transport of their gametes. However, in addition to essential nutrients, many floral rewards (nectar, pollen) also contain defensive toxins such as alkaloids, with largely unexplored consequences for plant-pollinator interactions. I investigated how three psychoactive and addictive plant alkaloids — caffeine, nicotine, and morphine — affect foraging behavior in generalist bumblebees (Bombus impatiens) using robotic flowers. Each of these chemicals affected pollinator foraging behavior, influencing the number and duration of their visits to flowers in …

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 …

Hierarchy In Sensation: Exploring The 40 Hz Auditory Steady State Synchrony In The Primary Auditory And Prefrontal Association Cortices, Deepshila Gautam

Electronic Theses and Dissertations

Auditory processing begins in the cochlea and ascends through brainstem relays to the cortex, where sound features with increasing complexity are encoded. The 40 Hz auditory steady-state response (ASSR) reflects induced gamma synchrony shaped by local cortical circuit dynamics. Disrupted 40 Hz ASSR is a consistent finding in schizophrenia, linked to N-methyl-D-aspartate receptor (NMDAR) hypofunction in inhibitory interneurons, making it a promising translational biomarker. While multiple ASSR generators have been identified, it is not known if these are redundant or represent unique activity. This dissertation investigates regional differences in 40 Hz ASSR across two principal generators: the primary auditory cortex …

The Effects Of Different Volume-Load On Sprint And Change Of Direction Performance, Damar K. Bobb

Electronic Theses and Dissertations

This study was designed to compare the effects of two different strength training protocols on sprint and change of direction (COD) performance in recreationally trained athletes. Participants were evaluated on maximal dynamic (1RM squat) and isometric (IMTP) strength, speed (30m sprint), and COD (5-0-5 test). The participants were divided into two groups (Low volume-heavy load group [LV], High volume-moderate load high-intensity endurance (HIE) group [HV]) after initial testing, for a 4-week training intervention using traditional and weightlifting derivative lifts. The training consisted of 5 sessions per week (3 sessions resistance training [RT], each about 40-50 mins; 2 sessions sprint & …

Isolation And Characterization Of Siderophore(S) From Pseudomonas Mosselii, Casey J. Stophel

Electronic Theses and Dissertations

Iron is essential for growth of most microorganisms. It functions as an important cofactor in many important biological processes. However, iron found in soil is rendered insoluble and unavailable to microorganisms for use. To overcome this, many bacterial species produce siderophores, a small organic molecule that has high affinity for iron. Siderophores allow for bacterial cells to obtain otherwise insoluble iron. Pseudomonas mosselii, a Gram negative bacterium, was isolated from a local soil sample. P. mosselii was found to produce siderophore(s) under iron restricted environment, however, they have not been characterized. Therefore, it was of interest to isolate, purify and …

Orchestrated Architecture Dismantling: Borrelia Burgdorferi’S Coordinated Destruction Of Adaptive Immune Responses, Craig A. Land

Electronic Theses and Dissertations

Borrelia burgdorferi represents the most prevalent vector-borne bacteria in North America, affecting ~476,000 Americans annually yet persisting despite robust immune responses. This project reveals spirochetes target adaptive immunity through coordinated lymphatic colonization and precision immune dysregulation.

Using comparative host models (C57BL/6 vs. reservoir Peromyscus leucopus), we demonstrate lymph node colonization within 48-hours, with spirochetes exploiting LYVE-1-positive lymphatic structures as dissemination highways while avoiding the interior of follicular regions. Critically, we identify targeted CD4+ T-cell elimination in germinal center border zones at 21-DPI, precisely when these cells should be coordinating protective immunity. Concurrent upregulation of inhibitory receptor CD32b creates molecular …

Photochemistry Of Quinones And Combustion-Derived Particles, Desiree J. Sarmiento

Electronic Theses and Dissertations

Quinones are ubiquitous species that can be produced from the photochemical aging of combustion-derived particles (CDPs). Polycyclic aromatic hydrocarbons (PAHs) are a major component of CDPs and are precursors to quinones and other oxidized products (OPAHs). My work first expanded on the PAH and OPAH photochemistry research of Dr. John Haynes, who showed that anthracene (ANT) oxidizes into 1,4-naphthoquinone (1,4-NAPQ), 1,4-anthraquinone (1,4-ANTQ), and 9,10-anthraquinone (9,10-ANTQ), and of Dr. Heather Runberg, who demonstrated the ability of ANT and these quinones to generate reactive oxygen species (ROS). Then at the Pacific Northwest National Laboratory (PNNL), I was given the opportunity to investigate …

Foldit Education Mode, Brett Schulz

Electronic Theses and Dissertations

Foldit education mode is a puzzle campaign within the protein folding video game Foldit. Education mode, initially designed as a classroom supplement for undergraduate biochemistry courses, has been expanded to provide a more comprehensive learning tool to players without a background in biochemistry. The edited and added levels teach players about protein biochemistry through playing puzzles designed to convey information and gameplay mechanics. The new Foldit education mode campaign features 49 levels grouped into 11 categories. The campaign has 6 new levels designed specifically for education mode and 4 levels adapted from the traditional Foldit campaign for use within education …

Carbon Monoxide Releasing Polymeric Micelles, Riya Joshi

Electronic Theses and Dissertations

Carbon monoxide (CO), traditionally known as a toxic gas, has emerged as a potential therapeutic agent due to its cytoprotective, anti-inflammatory, and vasodilatory properties. This study explores the development of CO-releasing polymeric micelles as a controlled delivery system for biomedical applications. Using ring-opening metathesis polymerization (ROMP), we synthesized diblock copolymers incorporating CO-releasing moiety diphenylcyclopropenone (DPCP) with hydrophilic polyethylene glycol (PEG) to enhance solubility and stability of the overall CO releasing system. Dynamic light scattering (DLS) and electron microscopy (EM) confirmed the formation of well-defined micelles, while fluorescence assays demonstrated efficient CO release with the use of Iridium photocatalyst under 470 …