Life Sciences Commons^™

The Spatial, Temporal, And Ecological Constraints Of Plant-Host Associated Microbial Communities, Jonathan Dickey

Doctoral Dissertations

With the development of next generation sequencing technology, ecologists have recently been able to describe microbial communities across a wide array of niches at an accelerated pace. De-novo-based patterns in richness and relative abundance have been described for bacterial and fungal communities in terrestrial, aquatic, and host-associated microhabitats. A recent synthesis has shown that these communities exhibit similar geographical patterns that have been traditionally described for plant and animals. Yet, there is a lack of hypothesis-based research for host-associated microbial communities. Throughout this dissertation, I will address how spatial scale, sequencing resolution, and manipulative rainfall exclusion govern host-associated microbial communities …

Making Sense Of Soil Microbiome Complexity For Plant And Ecosystem Function In A Changing World, Kendall K. Beals

Doctoral Dissertations

Soils contain the highest biodiversity on Earth. While the importance of the soil microbiome for larger-scale ecological phenomena such as nutrient and carbon cycling, plant growth and plant community dynamics is well-established, the fundamental question of the ecological and evolutionary function of this immense belowground microbial diversity for plant and ecosystem function still remains a great challenge in microbial ecology research. The objective of this dissertation is to understand how the importance of soil microbial community composition for plant and ecosystem function and how changes to soil microbial community composition from climate change-induced disturbance events, specifically fire, influence plant and …

Native Soil Virus Abundance, Composition, And Mobility Under Natural And Managed Agricultural Conditions, Regan Mcdearis

Doctoral Dissertations

Soil viruses are ubiquitous in the environment and important for their influence on host community composition and function. Viral infection influences host evolution, metabolism, function, diversity, community evenness, and more. As host bacteria play critical roles in agricultural systems, including nutrient cycling and soil aggregate formation, the influence which soil viruses have on their hosts makes them key players in these systems. However, many important questions remain regarding virus abundance and distribution under human imposed and natural conditions in agricultural systems. Understanding how these conditions impact virus abundance, transport, and community structure is critical for a broader understanding of soil …

Effect Of Herbicide Concentration On Atrazine, Pyroxasulfone, And Saflufenacil Dissipation Under Field And Lab Conditions, Randall Lee Landry

Doctoral Dissertations

Widespread herbicide resistant weeds over the last several years have fueled a renewed interest in the utility of soil-applied residual herbicides. Residual activity of a herbicide is based on a myriad of factors within and among environments. A common assumption used in simulation models examining herbicide persistence is that herbicide degradation is independent of application rate. These studies compared herbicide concentration on dissipation with three commonly used residual herbicides under field and lab conditions. Atrazine, pyroxasulfone, and saflufenacil represent herbicides with a relative field persistence of medium, high, and low, respectively. Field studies were conducted over two years where herbicides …

Interactions Between Soft Nanoparticles And Mammalian Cells, Mitchell Raith

Doctoral Dissertations

Nanoparticles have been of interest to the pharmaceutical industry since the 1980s. The first FDA approved nanoparticle-based therapies included liposomal anesthesia agents. Since then, the amount of FDA-approved nanoparticle therapies remains low. This is because nanoparticle-patient interactions can be very complex and are not well understood. Complicating factors also include increasing obesity rates among the patient population and many small animal pre-clinical trials are completed with healthy, lean animals. The biochemical differences between lean and obese patients prevents early studies from accurately predicting nanoparticle clinical behaviors. Many nanoparticles fail in trails. In this thesis, I aimed to uncover how nanoparticles …

Nodulin 26 Like Intrinsic Proteins: Structurally Similar Membrane Channels With Diverse Functions In Plant Hypoxia Stress, Metalloid Nutrition & Toxicity, Zachary Beamer

Doctoral Dissertations

Plant nodulin 26 intrinsic proteins are categorized into three groups (NIP I, II, and III) based on pore architecture. NIP II and III participate in metalloid nutrition, whilst the function of a third (NIP I) is less understood. Here we investigate the physiological function of one NIP I protein (Arabidopsis thaliana NIP2;1) as a lactic acid channel, and also explore the structural basis for metalloid and water permeability of NIP I and NIP II proteins in general. In addition, a strategy was developed for the purification and crystallization of soybean nodulin 26 as a step towards structure determination of a …

Multi-Omic Systems Biological Analysis Of Host-Microbe Interactions, Piet Jones

Doctoral Dissertations

Systems biology offers the opportunity to understand the complex mechanisms of various biological phenomena. The wealth of data that is produced, at an increasing rate, provides the potential to meet this opportunity. Here we take an applied approach to integrate multiple omic level data sources in order to generate biologically relevant hypotheses. We apply a novel analysis pipeline to model both, in concert, the microbial and transcriptomic signature from COVID-19 positive patients. We show patients may suffer from an increased microbial burden, with an increased pathogen potential. Gene expression evidence further shows patients may exhibit a compromised barrier immunity, owing …

Elk Abundance, Survival, And Health In The Cumberland Mountains Of Tennessee, Katherine Kurth

Doctoral Dissertations

Managing sustainable wildlife populations requires insight into population abundance and health. Since reintroduction, elk (Cervus canadensis) at the North Cumberland Wildlife Management Area (NCWMA) in Tennessee have shown marginal population growth using low-precision abundance estimates. Limited research investigating possible population limiting factors has occurred since evaluations conducted directly after translocation. To provide information necessary for effective population management, we estimated abundance, identified survival rates, and conducted mortality and health surveillance. Precise abundance estimates of eastern elk populations are challenging to obtain using traditional capture-recapture due to invasive handling of individuals and low detection in forested landscapes. Therefore, we …

Unraveling The Molecular Foundations Behind The Diverged Behaviors Of Mouse Insulin 1 And Insulin 2, Connecting Diabetes Risk With Glucocorticoid Treatment And Chronic Migraine Through The Analysis Of Islet Chemistry, And Capturing Key Posttranslational Modifications All Through The Application Of A Novel Lc-Ims-Ms Workflow, Connor Christopher Long

Select or Award-Winning Individual Scholarship

We display the capabilities of our established liquid chromatography-ion mobility spectrometry-mass spectrometry (LC-IMS-MS) workflow in the investigations of islet chemistry at the sub-single-islet level. We begin by characterizing the structural differences of Ins1 and Ins2 to present novel insights as to why their behaviors diverge. We then examine the effects of the stress hormone corticosterone, the rodent equivalent of human cortisol that is often used as a therapeutic, on pancreatic peptide hormone secretion. We also uncover the molecular connection behind the inverse relationship between type 2 diabetes (T2D) risk and chronic migraine via the neuropeptides CGRP and PACAP. Lastly, we …

A Study Of The Effect Of Physiological Stressors On Hypothalamic Regulation Of Reproduction Using An In Vitro System, Lisa L. Amelse

Doctoral Dissertations

Stressors have a negative impact on reproductive efficiency in humans and other animals, which has an economic cost due to infertility treatments for humans and reduced income for food producers. We wished to determine the molecular pathways by which metabolic disturbances and low-level inflammation impact the hypothalamic pituitary gonadal (HPG) axis using an in vitro model. To this end, we used the GT1-7 cell line, an immortalized line expressing the Kiss1R receptor that responds to kisspeptin stimulation with the release of GnRH to assess the impact of stressors on the GnRH-releasing cells. Additionally, we used the KTaV-3 and KTaR-1[A1] …

Improving The Biocompatibility Of The Bio-Inorganic Interface For Enhanced Photosystem I-Based Biophotovoltaic Device Performance, Alexandra H. Teodor

Doctoral Dissertations

The world’s energy demands are projected to increase by nearly 50% by the year 2040, and consumption of carbon-based fuels continues to release greenhouse gases such as carbon dioxide and methane into the atmosphere. This has been causally linked with climate change and increased extreme weather events, which has been further linked to adverse health outcomes and negative effects on biodiversity, food security, and increased disease transmission. Clearly, there is a need for a sustainable, carbon-free, and cost-effective method of energy production to meet growing energy production demands. The sun irradiates Earth’s surface annually with ~80,000 terawatts (TW), making solar …

Chemistry And Functionality Of Plant Waxes: Applications Toward Postharvest Coatings, Francisco Miguel Angel Leyva Gutierrez

Doctoral Dissertations

The cuticle of all higher-plants is covered in lipidic layers of amorphous and crystalline waxes. The chemical composition and structure of cuticular waxes impart numerous functional properties to the surfaces of plants. Moreover, plant waxes are valuable industrial products with myriad applications; the postharvest coating of agricultural commodities for preservation serves as a salient example. There is an unfulfilled need in the agricultural sector for alternative wax materials to reduce reliance on imported waxes of botanical origin. Plant waxes are inherently complex mixtures composed of n-alkanes, as well as aliphatic alcohols, aldehydes, fatty acids, ketones, esters, and derivatives thereof. …

Plant Community Responses To Interactive Anthropogenic Disturbances Along A Natural-Wildland-Urban Gradient And Undergraduate Students’ Attitudes Toward Disturbances, Mali M. Hubert

Doctoral Dissertations

Anthropogenic disturbances are defined as any change caused by human activity that alters biodiversity. Wildfire and urbanization disturbances are among the most influential on the landscape because of their individual and interactive properties. Areas deemed wildland-urban interfaces (WUI; area where environment intermingles with human-built structures) are increasing near protected lands because of human population growth and movement, which often facilitates fire ignitions by humans. Houses that are adjacent to or overlap with wildland vegetation can complicate protection of urban development and wildlands from fires. The expansion of the WUI due to population growth will exacerbate fire risk, which can ultimately …

Evaluation Of Insecticide Resistance In Populations Of Tobacco Thrips, Frankliniella Fusca (Hinds), And Plant Density Effects On Thrips Injury To Cotton, Jessica L. Krob

Masters Theses

Two field studies were performed in Tennessee to evaluate the effects of plant density and seed spacing on thrips injury to upland cotton (Gossypium hirsutum L.). The plant density study consisted of seeding rate treatments that were low, normal, high, and very high, relative to university Extension recommendations. In the plant spacing study, treatments were implemented using nearly identical seeding rates but with relatively uniform seed spacing versus a clumped, “hill-dropped” spacing. In both studies, the seed was either treated with an insecticide (imidacloprid) and a fungicide or only with a fungicide. Due to variable environmental conditions, the results …

Improving Water And Plant Growth Regulator (Pgr) Management Practices In Cotton: Cultivar Physiological Responses And Pgr Rates, Kurt Wedegaertner

Masters Theses

Cotton (Gossypium hirsutum L.) is grown in an increasingly unpredictable climate and often under rainfed conditions. Without irrigation to alleviate common drought conditions, cultivar selection becomes a primary tool in mitigating the negative effects of water-deficit stress. Cultivars can differ in water use under water-limited environments, which can affect crop performance. Moreover, cotton management must involve balancing vegetative and reproductive growth through the use of plant growth regulators (PGR) due to the plant’s perennial growth pattern. The efficacy of PGRs are dependent on many variables including environmental conditions, irrigation, and genetics (cultivar). In 2020 and 2021, a series of …

Mathematical Modeling Suggests Cooperation Of Plant-Infecting Viruses, Joshua Miller, Vitaly V. Ganusov, Tessa Burch-Smith

Chancellor’s Honors Program Projects

No abstract provided.

Locked Nucleic Acid Aptamer And 10 Nm Gold Nanoparticles Increases The Sensitivity Of A Prion Protein Detection Assay, Haley Channell

Chancellor’s Honors Program Projects

No abstract provided.

Microplastics Exposure In At-Risk Myotis Lucifugus Bats Of The Northeastern United States, Leah Crowley

Chancellor’s Honors Program Projects

No abstract provided.

Investigation Of The Ectocranial Squamosal Suture To Estimate Age-At-Death, Navit S. Nachmias

Chancellor’s Honors Program Projects

No abstract provided.

Investigating The Role Of Dullard And Tmem-188 In Lipid Droplet Biogenesis In Mammalian Cells, Mia Kaitlin Buono

Chancellor’s Honors Program Projects

No abstract provided.

Plant Neighbor Interactions Of A Native Goldenrod Impact Abundance And Composition Of Pollinator Communities, Emma P. Kruse

Chancellor’s Honors Program Projects

No abstract provided.

Novel Ultraviolet Light Technologies For The Inactivation Of Murine Hepatitis Virus, A Sars-Cov-2 Surrogate, Alexia E. Angelos, Doris H. D'Souza

Chancellor’s Honors Program Projects

No abstract provided.

Defining Interactions Between Deformable Dna Origami And Lipid Bilayers Through Molecular Dynamics Simulation, Zachary A. Loyd

Chancellor’s Honors Program Projects

No abstract provided.

Mutations In The N-Terminus Of The Mod(Mdg4) Btb Domain Reveal An Unexpected Role Of Mod(Mdg4) In Chromosome Segregation In Female Meiosis, Gwyneth D E Walker, Bruce D. Mckee

Chancellor’s Honors Program Projects

No abstract provided.

Crispr-Cas In The Field Of Dentistry: A Comprehensive Collection Of The Potential Uses Of Crispr-Cas9 In Dental Health Care, Lexi Elaine Bales

Chancellor’s Honors Program Projects

No abstract provided.

Climate-Driven Selection Results In Powerful Geographic Framework For Predicting Phenotype, Alexandra Neild

Masters Theses

Our ability to prepare for and mitigate the likely ecological and evolutionary impacts of climate change largely depends upon our ability to predict the phenotypic responses of organisms that allow them to persist, adapt, and migrate along environmental stress gradients. Using fifteen populations of cottonwoods, a dominant riparian forest tree, that are distributed along elevation gradients and represent three genetic provenances, we hypothesized and show that: 1) populations within a provenance demonstrate parallel evolutionary responses to climatic gradients associated with elevation; and 2) the evolutionary effects of elevation on bud-break phenology varied by provenance. Across all populations, we find strong …

Assessing Global Meat Trade & Local Infrastructure Upgrades, Mary Lynn Marks

Masters Theses

This thesis is a combination of two distinct chapters. Chapter 1 focuses on human pandemics impacts on global meat trade. An increase in future mass global pandemics is expected as zoonotic diseases, globalization, and trade escalate. These pandemics affect nearly every industrial sector, with animal protein no exception. The COVID-19 pandemic continues to be the largest, most expansive, and unprecedented pandemic in a century. Labor shortages and supply chain defragmentation are only a portion the production process affected. Studies have analyzed species specific disease events’ effects on animal trade, such as those caused by the African Swine Fever amongst Chinese …

Neutrophil Subtype Differentiation In Campylobacter Jejuni Infection And Its Impact On T Cells And Colonic Epithelial Cells, Carolina Dolislager

Masters Theses

The discovery of neutrophil subtypes has expanded what is known about neutrophil functions, yet there is still much to learn about the role of these subtypes during bacterial infection. We investigated whether Campylobacter jejuniinduced differentiation of human neutrophils into the hypersegmented, CD16^hi/CD62L^lo[CD16hi/CD62Llo] subtype. In addition, we investigated whether C. jejuni-dependent differentiation of this neutrophil subtype induced cancer promoting activities ofhuman T cells and colonocytes, whichwere observed in other studies of hypersegmented, CD16^hi/CD62L^lo[CD16hi/CD62Llo] neutrophils. We found that C. jejunicauses a significant shift in human neutrophil populations to the hypersegmented, CD16 …

Assessing The Impact Of Parental Involvement On The Scaling Of Agricultural Technologies From School Garden To Home Farm Through Experiential Learning, Gracie Pekarcik

Masters Theses

Cambodia is a predominantly rural nation with a heavy dependence on agriculture, particularly smallholder rice farming systems. While several sustainable agricultural technologies have been successfully piloted on research stations or with small numbers of early adopters, questions remain on how to extend these technologies to large numbers of resource-poor smallholders. The Scaling Suitable Sustainable Technologies Project (S3-Cambodia) seeks to examine pathways for scaling sustainable intensification (SI) technologies to smallholder farmers. One of the identified pathways to scaling SI is through the education system. Cambodian youth serve as an entry point to extend target technologies to farm families through experiential learning …

A Disaggregated Analysis Of Beef Import Demand In Japan, Christina D. Greer

Masters Theses

Japan is an important partner for the U.S. beef industry and a major beef importing country. In 2020, Japan was the world’s third-largest importer of beef products (USDA, 2021). Although the Japanese beef market has been studied, research on the importance of product characteristics in determining import demand has been limited. The goal of this research is to provide a detailed analysis of how U.S. beef products compete in the Japanese market relative to other exporting countries based on prices, product form (chilled versus frozen), and product characteristics (boneless versus bone-in).

This study will focus on three key factors affecting …