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Resistance To Double-Stranded Rna (Dsrna) In Colorado Potato Beetle (Leptinotarsa Decemlineata Say): Genetic And Molecular Insights, Swati Mishra

Doctoral Dissertations

Double-stranded RNA (dsRNA) insecticides delivered through transgenic and non-transgenic means have been approved for commercialization in the US. As with other insecticides development of insect resistance is expected, necessitating the implementation of an Insecticide Resistance Management (IRM) framework for their long-term use. Laboratory-selected insect resistance strains can provide useful insights for an effective IRM plan. The Colorado potato beetle (CPB) is the target pest for the first commercial dsRNA foliar spray, making it an ideal model to study dsRNA resistance. In this dissertation, we studied the previously described CEAS 300 strain of CPB that exhibits >11,100-fold resistance against V-ATPase subunit …

Exploring The Dark Matter Of Proteomics, Armin G. Geiger

Doctoral Dissertations

Proteomics, particularly mass spectrometry (MS)-based proteomics, has become an essential tool in understanding biological complexity and function at the molecular level. However, a significant fraction of spectral data generated in these studies, often referred to as the "Dark Matter of Proteomics'', remains unexplored and unidentified, concealing potentially vital biological insights. This dissertation addresses the challenge of uncovering this dark matter through the innovative use of computational techniques to enhance peptide identification and quantification in Kalanchoë fedtschenkoi, a model organism for Crassulacean Acid Metabolism (CAM).

The research employs a quantification-centered approach to MS data analysis, leveraging both MS1 and MS2 …

Investigating Oxidative Stress And Large-Scale Genomic Reduction In Vibrio Natriegens Through The Development And Application Of New Genetic Techniques, Elizabeth Glasgo

Doctoral Dissertations

Vibrio natriegens is the fastest replicating bacterium and recent work has demonstrated its potential for biotechnology and synthetic biology applications. While these industries have been the focus of V. natriegens research, it offers a promising system for diverse laboratory studies. However, currently a complete understanding of V. natriegens biology is lacking. As such, there is a need to advance genetic techniques and physiological understanding to better inform all aforementioned applications. Here we describe our contributions to the growing field of V. natriegens genetics and the application of these new techniques to study physiological processes and themes in genome evolution. Briefly, …

The Role Of Above- And Belowground Interactions For Plant Allocation, Sophia Carmel Turner

Doctoral Dissertations

My dissertation builds upon decades of research on plant resource allocation, by incorporating multispecies interactions, above- and belowground, with the overarching goal of uncovering the role of a whole community in shaping plant resource allocation and change to subsequent interactions. I accomplished this goal by establishing two controlled common garden experiments where I manipulated the biotic community that a focal plant is exposed to. Using these experiments, 1) I tested whether plant neighbors alter a focal plant’s resource allocation through changes to above- or belowground processes, and if these allocation changes resulted in any indirect effects on the focal plant’s …

Bee Friendly Beef: Integrating Pollinator-Friendly Native Forbs Into Native Grass Pastures, Jessica Prigge

Doctoral Dissertations

Native pastures present an opportunity to diversify that can support an array of animals, including pollinators and livestock. A variety of insect pollinators, important for both crop production and wild fauna persistence, are in population decline and benefit from native floral resources to sustain across the landscape. The goals of our work were to document blooming and forage characteristics of a variety of native forbs and to determine their establishment, persistence, and forage characteristics under different grazing rest regimens. We also sought to measure animal productivity between grass and diversified pastures under continuous stocking. Forbs established and persisted differently based …

Observing The Response Of The Caspian Sea Microbiome To Crude Oil Amendment Under Oxic And Hypoxic Conditions, Zabrenna Georgiana Griffiths

Doctoral Dissertations

The Caspian Sea is the world’s largest landlocked saline lake positioned between Europe and Asia and for its historic and large-scale oil reserves. These vast oil reserves have led to the development of an intricate network of pipelines, and drilling operations causing the environmental deterioration of the waterbody. Drainage from surrounding river basins brings an influx of pollutants from residential, industrial and agricultural origins which further compounds this issue. The endorheic nature of this waterbody causes the retention and accumulation of these pollutants, ultimately reducing water quality.

The increased nutrient input has steadily intensified eutrophication in this waterbody resulting in …

Impacts Of Climate Change On Mammalian Species Of Concern Within The Appalachian Ecoregion, Lauren M. Lyon

Doctoral Dissertations

Climate change and growth anthropogenic presence is a phenomenon impacting all species globally. Fortunately, with protection of key areas of suitable habitat and climate, we can alleviate the worst of biodiversity loss utilizing climate change refugia. This is apparent in the eastern United States, where the Appalachian Ecoregion naturally form a refugium compared to the surrounding landscape for many taxa and rare ecosystems. Particularly of interest are the at-risk relict boreal ecosystems found at elevation, which are otherwise restricted to the northern US and Canada, and numerous endemic taxa found only in this biodiverse region.

Recent studies have focused either …

Phenology, Olfactory Response, And Tritrophic Interactions Of Helicoverpa Zea And Chloridea Virescens On Hemp, Cannabis Sativa, Julian B. Cosner

Doctoral Dissertations

Industrial hemp, Cannabis sativa L., production has been revived in the United States following its legalization through the Agricultural Improvement Act of 2018 (a.k.a. 2018 Farm Bill). The corn earworm, Helicoverpa zea (Boddie), has been considered one of the most harmful insect pests in outdoor hemp production as larvae feed on the marketable grain and inflorescences where cannabinoid concentrations are highest. However, in Tennessee, a Heliothine complex, including corn earworm and the tobacco budworm, Chloridea virescens (F.), occurs on hemp. To investigate the seasonal incidence of these hemp pests, larvae were collected from hemp grown in different regions of Tennessee …

Xyway Lfr@Fmc Fungicide: Improving Corn (Zea Mays L.) Water Use Efficiency And Productivity Under Water-Deficit Stress And Dryland Conditions, Isha Poudel

Doctoral Dissertations

Triazole fungicide has the ability to protect crops from varying water stresses. Xyway LFR^@FMC is a triazole, at-plant fungicide and has been observed to improve plant performance under limited water conditions. A greenhouse study was conducted to assess the potential of Xyway LFR^@FMC in altering the ability of corn plants to control transpiration rates under water deficit-stress (DS) conditions. Greenhouse grown plants were treated with Xyway LFR^@FMC at 0.56, 0.77, 1.11,1.26 L ha^-1. Plants treated with 1.11 L ha^-1 reduced the amount of water loss in response to DS and had the highest fraction …

Understanding The Conformational Dynamics Of The A2a Adenosine Receptor By Single-Molecule Fluorescence, Shushu Wei

Doctoral Dissertations

G protein-coupled receptors (GPCRs) are one of the largest transmembrane receptor families. The wide expression and diverse signal transduction functions make them an ideal target for characteristic drug design. The A_2A adenosine receptor (A_2AAR), a representative of class A GPCRs, has been extensively used to reveal the structural information of class A GPCRs. As a purinergic receptor, A_2AAR is activated by adenosine in the human body, triggering cyclic adenosine monophosphate (cAMP) and immunosuppression pathways. A_2AARs are highly expressed in the brain and are crucial in regulating glutamate and dopamine release. As a result, …

Applying A One Health Approach To Expand Disease Surveillance In Eastern Wildlife, Eliza L. Baker

Doctoral Dissertations

Urban wildlife carry numerous diseases of veterinary and human health importance. Many of these diseases are emerging into new geographic areas, including the southeastern United States, due to a combination of climate change, urbanization, and migration. Urban wildlife can act as excellent sentinels for these diseases, providing doctors and veterinarians with a better understanding of the risks to their patients. We sought to better understand a variety of diseases of human and animal concern via urban wildlife surveillance. We found a high prevalence of numerous zoonotic and companion animal diseases in wildlife, both with and without significant health impacts on …

Investigating And Developing Strategies For The Expression Of Biosynthetic Genes In Vitro And In Vivo, Tien Thuy Tran

Doctoral Dissertations

Natural products have historically served as a rich source for a wide range of useful applications such aspesticides, veterinary agents, therapeutics, and bioproducts. To discover new natural products, manipulate them for analog generation, and harness the potential of these bioactive compounds for synthetic biology, it is necessary to develop robust methods for the expression of biosynthetic genes. A broad range of clinically useful natural products originate fromactinomycetes, especially those from the genus Streptomyces, which have been recognized as one of the predominant sources of microbial bioactive natural products. Actinobacteria are known for their large genomes, Guanine-Cytosine rich, and complex …

Physical Activity On Multiuse Trails And In A Novel Bike Park Within An Urban Wilderness, Douglas Gregory

Doctoral Dissertations

Research has shown that the presence of, access to, and use of parks and trails is associated with increased levels of PA. However, little research exists on nature-based, recreational multiuse trails and bike-specific amenities within parks and their impact on PA. Therefore, to explore the effect trails and bike parks have on PA, this dissertation conducted three investigations to: 1) determine the impact of trail/greenway interventions on PA, 2) investigate how seasonality and weather influence nature-based recreational trail use, and 3) develop a demographic and PA profile of bike park users.

Investigation 1 (Chapter 4) systematically reviewed the literature specific …

Computational Study Of Confined Cytoskeletal Assemblies: Simple Rules, Complex Behavior, Oghosa Honor Akenuwa

Doctoral Dissertations

The actin cytoskeleton is crucial for cellular processes and proper organization in cells. Physical regulators like actin crosslinking proteins, molecular motors, and physical confinement significantly impact the organization of the actin cytoskeleton. Despite advances, much remains unknown about how these physical regulators affect actin organization. In this thesis, we employ coarse-grained computer simulations to investigate the effect of physical regulators on the dynamics and organization of semiflexible actin filaments. First, we explore the role of crosslinker properties and confinement shape on actin organization by varying the system shape, the number and type of crosslinking proteins, and the length of filaments. …

Of Hosts And Habitats: The Ecological And Evolutionary Patterns Of The Amphibian Skin Microbiome, Benjamin Houston Holt

Doctoral Dissertations

The skin microbiome of amphibian hosts can inhibit growth of pathogenic fungi, contribute to anti-predator compounds in newts, and is linked with sex-specific scents in frogs. However, despite growing evidence of symbiont importance to amphibians, how symbionts are acquired and maintained on hosts remains poorly resolved. Microbiomes exist on a dynamic spectrum from casual assemblages to intricate systems, and community members vary in fidelity and association to hosts. The establishment of these communities involves complex interactions between symbionts, host traits, and source communities. I seek to enhance our understanding by assessing the spatial-temporal patterns of the salamander skin microbiome relative …

Bridging Biological Systems With Social Behavior, Conservation, Decision Making, And Well-Being Through Hybrid Mathematical Modeling, Maggie Renee Sullens

Doctoral Dissertations

Mathematical modeling can achieve otherwise inaccessible insights into bio-logical questions. We use ODE (ordinary differential equations) and Game Theory models to demonstrate the breadth and power of these models by studying three very different biological questions, involving socio-behavioral and socio-economic systems, conservation biology, policy and decision making, and organismal homeostasis.

We adapt techniques from Susceptible-Infected-Recovered (SIR) epidemiological models to examine the mental well-being of a community facing the collapse of the industry on which it’s economically dependent. We consider the case study of a fishing community facing the extinction of its primary harvest species. Using an ODE framework with a …

Development Of An Integrated Workflow For Nucleosome Modeling And Simulations, Ran Sun

Doctoral Dissertations

Nucleosomes are the building blocks of eukaryotic genomes and thus fundamental to to all genetic processes. Any protein or drug that binds DNA must either cooperate or compete with nucleosomes. Given that a nucleosome contains 147 base pairs of DNA, there are approximately 4^147 or 10^88 possible sequences for a single nucleosome. Exhaustive studies are not possible. However, genome wide association studies can identify individual nucleosomes of interest to a specific mechanism, and today's supercomputers enable comparative simulation studies of 10s to 100s of nucleosomes. The goal of this thesis is to develop and present and end-to-end workflow that serves …

Exploring Soil Microbial Dynamics In Southern Appalachian Forests: A Systems Biology Approach To Prescribed Fire Impacts, Saad Abd Ar Rafie

Doctoral Dissertations

Prescribed fires in Southern Appalachian forests are vital in ecosystem management and wildfire risk mitigation. However, understanding the intricate dynamics between these fires, soil microbial communities, and overall ecosystem health remains challenging. This dissertation addresses this knowledge gap by exploring selected aspects of this complex relationship across three interconnected chapters.

The first chapter investigates the immediate effects of prescribed fires on soil microbial communities. It reveals subtle shifts in porewater chemistry and significant increases in microbial species richness. These findings offer valuable insights into the interplay between soil properties and microbial responses during the early stages following a prescribed fire. …

The Identification Of Small Molecule Inhibitors To Candida Albicans Phosphatidylserine Synthase, Yue Zhou

Doctoral Dissertations

Candida albicans phosphatidylserine (PS) synthase, encoded by the CHO1 gene, has been identified as a potential drug target for new antifungals against systemic candidiasis due to its importance in virulence, absence in the host and conservation among fungal pathogens. This dissertation is focused on the identification of inhibitors for this membrane enzyme. Cho1 has two substrates: cytidyldiphosphate-diacylglycerol (CDP-DAG) and serine. Previous studies identified a conserved CDP-alcohol phosphotransferase (CAPT) binding motif present within Cho1, and here we revealed that mutations in all but one conserved amino acid within the CAPT motif resulted in decreased Cho1. For serine, we have predicted a …

Characterization Of Radiotolerance In Potato And Development Of A Gamma Radiation Phytosensor., Robert Graham Sears

Doctoral Dissertations

As humans pursue space travel and nuclear energy, the risk of harm from ionizing radiation increases. On Earth or in space, plants are essential to our personal and environmental health. Plants serve as sentinels, bioremediators and food sources in areas of high ionizing radiation, therefore it is essential to understand how ionizing radiation affects plant biology. This work aimed to understand plant responses to ionizing radiation in the potato chassis and apply that knowledge to generate novel phenotypes for nuclear energy and space applications. The first gamma radiation phytosensor was developed for monitoring at standoff distances greater than three meters. …

Impact Of Cadmium Stress On Soil Virus Reproduction And The Persistence Of Viruses Under Abiotic Conditions, Zhibo Cheng

Doctoral Dissertations

Soil viruses are ubiquitous and greatly impact the structure and function of soil microbial communities, with their effects modulated by various environmental factors. This study investigates the inactivation of naturally occurring soil viruses in sterilized soil, as well as the effects of cadmium (Cd) exposure and carbon (C) and nitrogen (N) nutrient availability on the population dynamics of virus-host communities in agricultural soil.

Lab-scale slurry and unsaturated experiments were performed to examine virus inactivation in the absence of host bacteria in sterilized soil. In slurry experiments, virus abundance declined by over 90% after 10 days of incubation. The addition of …

Integration Of Raman Spectroscopy And Python-Based Data Analysis For Advancing Neurobiological Research, Natalie E. Dunn

Doctoral Dissertations

The field of Raman spectroscopy continues to expand into biological applications due to its usefulness as a non-invasive technique that can be utilized qualitatively and quantitatively. However, the inherent weakness of Raman scattering leads to the need for each collected spectra to undergo a preprocessing step to remove noise, background drift, and cosmic rays. Biological research in particular needs large datasets due to the increased variability in samples. As datasets grow, the need to perform preprocessing on each individual spectra becomes daunting. Often, these steps are done by hand with the help of specialized software programs. Preprocessing can be accelerated …

Characterization Of Lignin Structural Variability And The Associated Application In Genome Wide Association Studies, Nathan D. Bryant

Doctoral Dissertations

Poplar (Populus sp.) is a promising biofuel feedstock due to advantageous features such as fast growth, the ability to grow on marginal land, and relatively low lignin content. However, there is tremendous variability associated with the composition of biomass. Understanding this variability, especially in lignin, is crucial to developing and implementing financially viable, integrated biorefineries. Although lignin is typically described as being comprised of three primary monolignols (syringyl, guaiacyl, p-hydroxyphenyl), it is a highly irregular biopolymer that can incorporate non-canonical monolignols. It is also connected by a variety of interunit linkages, adding to its complexity. Secondary cell wall …

Regulation Of Protein Synthesis In Arabidopsis Thaliana Through A Bioinformatic And Mathematical Lens, Ricardo Andres Urquidi Camacho

Doctoral Dissertations

Organisms exist under constantly varying environmental and internal conditions, which necessitate the differential regulation of gene expression. To synthesize proteins, the ribosome translates the information encoded in the nucleotide sequence of an mRNA into the final, functional amino acid sequence. Knockouts of ribosomal proteins lead to lethality. One such protein is the ribosomal protein 6 of the small subunit (eS6/RPS6). We confirmed that the knockout of either one of two eS6 paralogs in Arabidopsis leads to stunted growth and chlorosis. Here, these phenotypes have been further characterized in seedlings by precisely quantifying the ribosome loading of mRNAs as well as …

Exploring The Regulation Of A Bacillus Pumilus Bioplastic Degrading Protein, Elise Keara Phillips

Doctoral Dissertations

Biodegradable plastics are being adopted to reduce the environmental impacts associated with petroleum-based plastics, including long residence times, and reliance on fossil fuels as a feedstock. Microbial degradation of bioplastics is still poorly understood, which leads to inconsistent degradation outcomes and challenges for implementation. Bacillus pumilus B12 degrades the biodegradable bioplastic polylactic acid (PLA) via the protease AprE, but the regulatory mechanisms controlling aprE expression in B. pumilus B12 are largely unknown. To explore this question, we established developed a conjugation- based method to introduce DNA into B. pumilus B12 and diverse Bacillus species that is applicable to environmental and …

Novel Microbial Guilds Implicated In N2o Reduction, Guang He

Doctoral Dissertations

N₂O is a long-recognized greenhouse gas (GHG) with potential in global warming and ozone depletion. Terrestrial ecosystems are a major source of N₂O due to imbalanced N₂O production and consumption. Soil pH is a chief modulating factor controlling net N₂O emissions, and N₂O consumption has been considered negligible under acidic conditions (pH <6). In this dissertation, we obtained solids-free cultures reducing N₂O at pH 4.5. Furthermore, a co-culture (designated culture EV) comprising two interacting bacterial population was acquired via consecutive transfer in mineral salt medium. Integrated phenotypic, metagenomic and metabolomic analysis dictated that the Serratia population excreted certain …

Roles Of Soil Pores In Determining Water Retention And Microbial Dynamics, Huihui Sun

Doctoral Dissertations

Soil pore provides an essential habitat for microbial communities to participate in various biogeochemical processes. The complex pore spaces, which are defined by the arrangement of particles of varying sizes, govern the distribution of water for microbial dispersal and movement and microbial interaction with one another, such as bacterial cell-to-cell and bacterium-virus interactions. This research focused on exploring how soil pores influence soil water retention and bacterial interactions and quantify the spatial distribution of bacteria and viruses in fine-scale of soil pores. Using a mathematical model, this study simulated a soil water retention curve based on the relationship between soil …

"You're Not Thriving, You're Just Trying To Survive The Environment That You're In:" Mental Performance Consultants' Narratives Of Emotional Abuse In Sport, Victoria Lynn Bradshaw

Doctoral Dissertations

Emotional abuse is defined as “a pattern of deliberate non-contact behaviors by a person with a critical relationship that has the potential to be harmful” (Stirling & Kerr, 2008, p. 178). Specifically, in the context of sport, emotional abuse is one of the more frequently occurring forms of abuse (Kavanagh, Brown & Jones, 2017; Kirby, Greaves & Hankvisky, 2000; Wilson & Kerr, 2021). Years after the termination of those emotionally abusive experiences, athletes are left to try and cope with and manage the short and long-term impacts that tend to develop as a result of repeated exposure to harmful behaviors …

Retinoic Acid, Insulin, And Cycloheximide Alter Glycogen Homeostasis In Differentiating L6 Myoblasts, Aaron Armstrong

Doctoral Dissertations

Glycogen synthesis in skeletal muscle (SM) is responsible for the majority of post-prandial glucose disposal in healthy individuals. In type 2 diabetes mellitus (T2DM), compromised skeletal muscle glycogen synthesis contributes to hyperglycemia. L6 rat SM cells can develop insulin resistance with prolonged insulin stimulation and provide an in vitro model for mechanistic dysfunction in glycogen homeostasis. SM glycogen is synthesized by glycogen synthase (GS) in response to insulin stimulation. Canonically, insulin signaling increases GS activity through inhibition of its Ser641 regulator glycogen synthase kinase-3β (GSK3β) by protein kinase B (AKT). Proximal insulin signaling activates AKT via Ser473 phosphorylation which proceeds …

Population Abundance And Growth Of Elk (Cervus Canadensis) In Western North Carolina, Jessica Braunstein

Doctoral Dissertations

In an effort to restore extirpated elk to their previous range, 52 elk were reintroduced to Great Smoky Mountains National Park (GRSM) in North Carolina during 2001 and 2002. Since their reintroduction, elk numbers have increased and their range has extended beyond GRSM boundaries. My primary research objectives included estimating population abundance, apparent survival, per capita recruitment, and population growth rate of elk in North Carolina. I used spatially explicit capture-recapture (SECR) models based on fecal DNA to identify individual elk and estimate population abundance and growth in the region. Technicians and I walked a series of transects throughout the …