Digital Commons Network^™

The Effects Of Food Safety Standards On Trade And Welfare: The Case Of Eu Shrimp Imports, Xiaoqian Li

Theses and Dissertations--Agricultural Economics

This research explores the link between a gravity model and welfare frameworks and then applies the quantitative model system to analyze how trade and welfare is affected by the Minimum Required Performance Limits (MRPL) in the shrimp importing market of European Union.

The quantitative model system consists of two parts: first, this study uses the “phi-ness” gravity model to investigate the trade effects of MRPL on EU shrimp market. The “phi-ness” gravity model partitions the standard variables to avoid biased estimation caused by the correlation between time and country fixed effects and policy variables. The Poisson Pseudo Maximum Likelihood (PPML) …

Assessing And Mitigating Lawn Insecticide Hazards To Bees And Other Beneficial Invertebrates, Jonathan Lane Larson

Theses and Dissertations--Entomology

Turfgrass settings, including lawns, golf courses, and sports fields, support many beneficial invertebrates that provide important ecosystem services. These non-target organisms and their associated predation, decomposition, and pollination services can be disrupted by the use of certain insecticides. I compared the ecotoxicity of representatives from three major turf insecticide groups, the neonicotinoids, premix formulations, and the anthranilic diamides, in lab and field realistic settings in order to inform industry initiatives towards environmental sustainability.

In lab and field bioassays clothianidin, a neonicotinoid, and a premix clothianidin/pyrethroid spray were acutely toxic to beneficial insects. Populations of predators, springtails, and earthworms, as well …

Characterization Of Jabba, A Ricin-Resistant Mutant Of Leishmania Donovani, Megan Rhea Phillips

Theses and Dissertations--Molecular and Cellular Biochemistry

The abundant cell-surface lipophosphoglycan (LPG) of Leishmania parasites plays a central role throughout the eukaryote’s life cycle. A number of LPG-defective mutants and their complementing genes have been isolated and have proven invaluable in assessing the importance of LPG and related glycoconjugates in parasite virulence. While ricin agglutination selection protocols frequently result in lpg- mutants, one L. donovani variant we isolated, named JABBA, was found to be lpg+. Procyclic (logarithmic) JABBA expresses significant amounts of a large-sized LPG, larger than observed from procyclic wild-type but similar in size to LPG from wild-type from metacyclic (stationary) phase.

Structural analysis of …

Food Shopping Habits And The Association With Diet, Crystal Danielle West

Theses and Dissertations--Nutrition and Food Systems

Research suggests that the connection between poor diet and obesity among rural residents may be partially explained by limited access to healthy foods including fruits and vegetables (F&V). Based on federal suggestions to improve access, the purpose of this study was to assess the relationship between food shopping habits food venues and dietary intake of residents in rural counties of Kentucky. In May, 2013, a telephone survey was conducted using random-digit dial methods among n=149 participants in all three counties. Results showed that grocery shopping at supermarkets had a moderate positive correlation with F&V intake (r=.357, .348). These findings suggest …

Soil And Biosolid Nano- And Macro-Colloid Properties And Contaminant Transport Behavior, Jessique L. Ghezzi

Theses and Dissertations--Plant and Soil Sciences

Despite indications that they are potential contaminant transport systems and threats to groundwater quality, very little effort has been invested in comparing contaminant transport behavior of natural environmental nanocolloids and their corresponding macrocolloid fractions in the presence of As, Se, Pb, and Cu contaminants. This study involved physico-chemical, mineralogical, stability and contaminant-transport characterizations of nano- (< 100 nm) and macro-colloids (100-2000 nm) fractionated from three Kentucky soils and one biosolid waste. Particle size was investigated with SEM/TEM and dynamic light scattering. Surface reactivity was estimated using CEC and zeta potential. Mineralogical composition was determined by XRD, FTIR, and thermogravimetric analyses. Sorption isotherms assessed affinities for Cu²⁺, Pb²⁺, AsO₃^-, and SeO₄^-2 contaminants, while settling kinetics experiments of suspensions at 0, 2 and 10 mg/L contaminants determined stability and transportability potential. Undisturbed 18x30 cm KY Ashton Loam soil monoliths were also used for …

Understanding The Role Of Membrane Localized Ugt80b1 Encoding For Udp-Glucose: Sterol Glucosyltransferase In Plant Development, Meera Nair

Theses and Dissertations--Plant and Soil Sciences

Sterols have been identified as major components of membrane lipids that are part of specialized membrane domains necessary for organizing events such as polar protein targeting and signal transduction in plants, fungi and animals. However a common modification of sterols is the addition of sugar moieties via glycosylation abundantly found in plants. An exact physiological role for such diversification of sterols in plants is still unknown. Using reverse genetics and transcriptomics we show that UDP-glucose: sterol glucosyltransferase encoded by UGT80B1 is necessary for correct epidermal patterning in Arabidopsis root. Patterning of hair cells (trichoblasts) and non-hair cells (atrichoblasts) in the …

Computational Identification And Molecular Verification Of Mirna In Eastern Subterranean Termites (Reticulitermes Flavipes), Tian Yu

Theses and Dissertations--Entomology

Reticulitermes flavipes is one of the most common termite species in the world, and has been an intriguing research model due to its ecological and biological and economic significance. The fundamental biological question addressed by this study is to elucidate the role of miRNAs in termite development and how miRNA can influence labor division. miRNAs are short non-coding RNAs that have an important role in gene regulation at post-transcriptional level, and can potentially be involved in the regulation of caste polyphenism. Using a computational approach, I identified 167 conserved and 33 novel miRNAs in the dataset. miR-iab-4 and 19 other …

Molecular Mechanism Of Human Mismatch Repair Initiation, Sanghee Lee

Theses and Dissertations--Nutritional Sciences

DNA mismatch repair (MMR) is a highly conserved pathway that maintains genomic stability primarily by correcting mismatches generated during DNA replication. MMR deficiency leads to microsatellite instability (MSI), which is a hallmark of HNPCC (Hereditary Nonpolyposis Colorectal Cancer). Human mismatch repair is initiated by MutSα, a heterodimer of MSH2 and MSH6 subunits. Mismatch binding by MutSα triggers a series of downstream MMR events including interacting and communicating with other MMR proteins. The ATPase domain of MutSα is situated in the C-termini of its both subunits, and ATP binding is required for dissociation of MutSα from a mismatch. In eukaryotic cells, …

The Role Of Exercise In Polychlorinated Biphenyl Induced Cardiovascular Disease, Margaret O'Bryan Murphy

Theses and Dissertations--Nutritional Sciences

Cardiovascular disease remains the leading cause of death in Western societies. Endothelial dysfunction is one of the initiating steps in the development of atherosclerosis. While there is a strong correlation with a person’s genetics, lifestyle factors including smoking, physical activity, and diet can significantly increase a person’s susceptibility to the development of atherosclerosis. In addition to these lifestyle factors, there is a strong body of evidence linking exposure to environmental pollutants including persistent organic pollutants such as polychlorinated biphenyls to increased cardiovascular disease and mortality. It has been well-established that exercise protects against cardiovascular disease, but whether exercise can modulate …

Role Of Scavenger Receptor Class B Type I In Thymopoiesis, Zhong Zheng

Theses and Dissertations--Nutritional Sciences

T cells, which constitute an essential arm in the adaptive immunity, complete their development in the thymus through a process called thymopoiesis. However, thymic involution can be induced by a couple of factors, which impairs T cell functions and is slow to recover. Therefore, understanding how thymopoiesis is regulated may lead effort to accelerate thymic recovery and improve immune functions in thymocyte-depleted patients. In this project, we identified scavenger receptor BI (SR-BI), a high density lipoprotein (HDL) receptor, as a novel modulator in thymopoiesis. In mice, absence of SR-BI causes a significant reduction in thymus size after puberty and a …

Modeling Site Suitability For Establishing Dedicated Energy Crops In Northern Kentucky, Sandhya Nepal

Theses and Dissertations--Forestry and Natural Resources

Dedicated energy crops have the potential to supply a sustainable biomass feedstock to support the bioenergy industry. However, a major constraint for promoting energy crops has been the availability of land for establishing energy crops. In this study, we developed a spatially-explicit model to identify suitable and economically feasible sites for establishing energy crops based on biomass price, production costs and site-specific biomass productivity. Results from our study provided an objective evaluation of factors that influence the amount and spatial distribution of land suitable for establishing energy crops. In addition, our model had the ability to capture variation across the …

Use Of Genomic Tools To Discover The Cause Of Champagne Dilution Coat Color In Horses And To Map The Genetic Cause Of Extreme Lordosis In American Saddlebred Horses, Deborah G. Cook

Theses and Dissertations--Veterinary Science

Champagne dilution of coat color in horses is caused by dominant gene action. Three sire families were identified as segregating for this trait. Genome wide linkage analysis using 104 microsatellite DNA markers was used to map the gene to ECA14 (LOD > 11.0). Four genes, namely SPARC, SLC36A1, SLC36A2 and SLC36A3, were selected from the region implicated by linkage and their exons sequenced. DNA sequences were compared for two homozygotes for Champagne dilution, two heterozygotes and two horses without dilution. A single base change in exon 2 of SLC36A1 was found unique to horses exhibiting Champagne dilution. This change in base …

Examination Of The Snsag Surface Antigen Gene Family In Sarcocystis Neurona, Ablesh Gautam

Theses and Dissertations--Veterinary Science

Sarcocystis neurona is a protozoan parasite that causes the serious neurologic disease equine protozoal myeloencephalitis (EPM). The life cycle of S. neurona progresses through multiple developmental stages that differ morphologically and molecularly. The S. neurona merozoite surface is covered by multiple related proteins, which are orthologous to the surface antigen (SAG) gene family of Toxoplasma gondii. The SAG surface antigens in T. gondii and another related parasite Neospora caninum are life cycle stage-specific and seem necessary for parasite transmission and persistence of infection. The present research was conducted to explore the gene family of SnSAGs in S. …

Corn (Zea Mays L.) Yield Response To Defoliation At Different Row Widths, Martin Leonardo Battaglia

Theses and Dissertations--Plant and Soil Sciences

Corn (Zea mays L.) defoliation experiments have been conducted for more than 120 years. However, there is limited data on the effect of row width on defoliation in modern hybrids. A two-year experiment was conducted in Lexington, Kentucky with two hybrids (113 relative maturity (RM) and 120 RM), two row widths (38 and 76 cm) and a combination of defoliation timings and severities: 0% defoliation (control), V7-100%, V14-50%, V14-100%, R2-50% and R2-100%. No yield difference among hybrids was observed in 2012. Yields were 26% greater in 38-cm rows than 76-cm rows in 2012. For 2013, corn yield for 38-cm …

Influence Of Spoil Type On Afforestation Success And Hydrochemical Function On A Surface Coal Mine In Eastern Kentucky, Kenton L. Sena

Theses and Dissertations--Forestry and Natural Resources

Surface coal mining in Appalachia has contributed to a suite of ecological impacts, both terrestrial and aquatic. Conventional reclamation in Appalachia leads to the development of hay/pasture systems dominated by nonnative grasses and legumes, with soils that are chemically and physically unfavorable to native tree growth. Several studies have shown that more weathered minespoils provide a better growth medium than unweathered spoils in Appalachia. Spoil segregation plots were constructed on Bent Mountain in Pike County, KY, to compare the suitability of three mine spoil types (BROWN weathered sandstone, GRAY unweathered sandstone, and MIXED sandstones and shales). In 2013 (after nine …

The Role Of Angiotensinogen In Atherosclerosis And Obesity, Congqing Wu

Theses and Dissertations--Nutritional Sciences

Angiotensinogen is the only known precursor in the renin-angiotensin system, a hormonal system best known as an essential regulator of blood pressure and fluid homeostasis. Angiotensinogen is sequentially cleaved by renin and angiotensin- converting enzyme to generate angiotensin II. As the major effector peptide, angiotensin II mainly function through angiotensin type 1 receptor.

Angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, and more recently renin inhibitors are widely known as the 3 classic renin-angiotensin system inhibitory drugs against hypertension and atherosclerosis. Here, we developed an array of regents to explore the effects of angiotensinogen inhibition. First, we demonstrated that genetic deficiency of …

Identifying Sources Of The Tragedy Of The Commons In Root Competition: A Spatially Explicit Simulation Model And Plants Grown In Transparent Growth Medium, R Deric Leith Miller

Theses and Dissertations--Biology

Existing research shows that plants produce less root when growing alone than when growing in competition with other plants. When plants under root competition over-allocate resources to roots at the cost of reproduction, it represents a Tragedy of the Commons. I constructed simulation models to determine the circumstances likely to give rise to a Tragedy of the Commons, and explore mechanisms by which plants may solve it. I grew plants in nutrient-rich transparent gel, allowing me to quantify root growth and development without destructive sampling. My plants responded positively to additional space and the presence of a competitor at full …

Grassland Sustainability In Kentucky: Case Studies Quantifying The Effects Of Climate Change On Slug Herbivory In Pastures And Different Home Lawn Systems On Turf Greenhouse Gas Emissions, Daniel Adam Weber

Theses and Dissertations--Plant and Soil Sciences

Grasslands comprise the greatest biome by land area, are sensitive to environmental factors affected by climate change, and can impact future climate change through their ability to store and release greenhouse gasses (GHGs). I performed two studies: 1) evaluated the effects of increased temperature and precipitation on slug herbivory/abundance and pasture forage production; 2) quantified different homeowner lawn system effects on soil-to-atmosphere GHG emissions. Climate change will likely affect pasture forage production, with implications for slug herbivory and abundance. I found little evidence that slugs have or will have significant effects on pasture production or plant community. Warming altered the …

Transmural Heterogeneity Of Cellular Level Cardiac Contractile Properties In Aging And Heart Failure, Premi Haynes

Theses and Dissertations--Physiology

The left ventricle of the heart relaxes when it fills with blood and contracts to eject blood into circulation to meet the body’s metabolic demands. Dysfunction in either relaxation or contraction of the left ventricle can lead to heart failure. Transmural heterogeneity is thought to contribute to normal ventricular wall motion but it is not well understood how transmural modifications affect the failing left ventricle. The overall hypothesis of this dissertation is that normal left ventricles exhibit transmural heterogeneity in cellular level contractile properties and with aging and heart failure there are region-specific changes in cellular level contractile mechanisms.

Age …

Structural Mechanisms Of Glucan Phosphatase Activity In Starch Metabolism, David A. Meekins

Theses and Dissertations--Molecular and Cellular Biochemistry

Starch is a water-insoluble glucose biopolymer used as an energy cache in plants and is synthesized and degraded in a diurnal cycle. Reversible phosphorylation of starch granules regulates the solubility and, consequentially, the bioavailability of starch glucans to degradative enzymes. Glucan phosphatases release phosphate from starch glucans and their activity is essential to the proper diurnal metabolism of starch. Previously, the structural basis of glucan phosphatase activity was entirely unknown. The work in this dissertation outlines the structural mechanism of activity of two plant glucan phosphatases called Starch EXcess4 (SEX4) and Like Sex Four2 (LSF2). The crystal structures of SEX4 …

Plant Growth Regulators And Herbicides For Management Of Poa Annua: Impact Of Biotypes And Behavior Of Flurprimidol In Turfgrass Species, Alexandra Perseveranda Williams

Theses and Dissertations--Plant and Soil Sciences

In 2011, Poa annua L. (Poa) biotypes were collected from greens of two golf courses in Lexington, Kentucky: 1.) The Lexington Country Club (LCC) and 2.) The University Club (UC). The samples were collected based on exhibiting one of two appearances while on the same green: 1.) dark green, with few to no flower heads (dark biotype) or 2.) light green, with numerous flower heads (light biotype). Two PGRs, paclobutrazol and flurprimidol, and two herbicides, bispyribac-sodium and amicarbazone, were applied to the plants both in the field and the greenhouse. Quality ratings were recorded weekly in both the …

Biomechanical Effects Of Trees And Soil Thickness In The Cumberland Plateau, Michael Shouse

Theses and Dissertations--Geography

Previous research in the Ouachita Mountains, Arkansas suggests that, on relatively thin soils overlying bedrock, individual trees locally thicken the regolith by root penetration into bedrock. However, that work was conducted mainly in areas of strongly dipping and contorted rock, where joints and bedding planes susceptible to root penetration are more common and accessible. This project extended this concept to the Cumberland Plateau, Kentucky, with flat, level-bedded sedimentary rocks. Spatial variability of soil thickness was quantified at three nested spatial scales, and statistical relationships with other potential influences of thickness were examined. In addition, soil depth beneath trees was compared …

Molecular Mechanisms Of Neuropilin-Ligand Binding, Matthew W. Parker

Theses and Dissertations--Molecular and Cellular Biochemistry

Neuropilin (Nrp) is an essential cell surface receptor with dual functionality in the cardiovascular and nervous systems. The first identified Nrp-ligand family was the Semaphorin-3 (Sema3) family of axon repulsion molecules. Subsequently, Nrp was found to serve as a receptor for the vascular endothelial growth factor (VEGF) family of pro-angiogenic cytokines. In addition to its physiological role, VEGF signaling via Nrp directly contributes to cancer stemness, growth, and metastasis. Thus, the Nrp/VEGF signaling axis is a promising anti-cancer therapeutic target. Interestingly, it has recently been shown that Sema3 and VEGF are functionally opposed to one another, with Sema3 possessing potent …

Leptin Resistance Induced Obesity And Diabetes Promote Neuropathological Changes In The Aging Brain, Thomas Platt

Theses and Dissertations--Molecular and Cellular Biochemistry

The aging brain is prone to the development of pathology and dementia. With a rapidly growing elderly population diagnoses of neurodegenerative diseases, such as Alzheimer’s disease (AD), frontotemporal dementia (FTD), and Parkinson’s disease are on the rise. Additionally, diabetes and obesity are linked to an increased risk of dementia. The convergence of this increasingly aged population with the obesity and diabetes epidemic give rise to new concerns regarding the future of prevention and treatment of neurodegenerative diseases. Our lab has previously shown that leptin, an adipokine involved in signaling satiety to the hypothalamus, can modulate the generation of the amyloid …

A Plant Trait-Based Approach To Evaluate The Ability Of Native C3 And C4 Grasses To Restore Functionality To A Remnant Bluegrass Savanna-Woodland In Kentucky, Usa., Jann E. Fry

Theses and Dissertations--Biology

Temperate Midwestern oak savannas are considered imperiled ecosystems with < 1 % remaining since the time of European settlement and are identified as critical areas for preservation. Restoration of Midwestern oak savannas is challenging due to the lack of accurate historical data, few intact remnants remaining to study, and lack of restoration ecology studies. A plant trait-based approach was used to evaluate the ability of six C₃ and three C₄ native bunchgrasses to restore functionality to a remnant savanna–woodland of the Bluegrass Region of Kentucky. The response and effect framework was used to assess the response of the nine native grasses according to the habitat filters of interannual precipitation, inter- vs. intra-specific competition, and simulated grazing. The effect traits associated with plant-soil nitrogen and carbon cycling were also assessed. The response traits of interannual competition and inter- vs. intra-specific competition along with the effect traits plant-soil nitrogen and carbon cycling were measured in a monoculture experiment …

Monitoring The Influence Of Acid Deposition On Soil And Implications To Forest Health In The Daniel Boone National Forest, Tyler M. Sanderson

Theses and Dissertations--Forestry and Natural Resources

Combustion of fossil fuels has contributed to many environmental problems including acid deposition. The Clean Air Act (CAA) was created to reduce ecological problems by cutting emissions of sulfur and nitrogen. Reduced emissions and rainfall concentrations of acidic ions have been observed since the enactment of the CAA, but soils continue to receive some acid inputs. Soils sensitive to acid deposition have been found to have low pH, a loss of base cations and a shift in the mineral phase controlling the activity of Al³⁺ and/or SO₄^2-. If inputs continue, soil may be depleted of base …

Targeted Knockout Of Beclin-1 Reveals An Essential Function In Ovary And Testis, Thomas R. Gawriluk

Theses and Dissertations--Biology

An estimated 12% of couples worldwide are infertile. The contributing factor is approximately equal between men and women with nearly 25% diagnosed as idiopathic. Despite the increasing numbers of couples seeking assistance from infertility clinics, few molecular mechanisms have been identified for treatment. Autophagy is an evolutionarily conserved cellular process for bulk degradation and recycling of cytosolic components through the lysosome to maintain homeostasis. Several studies have observed increased levels of autophagy during ovarian folliculogenesis and gonadal steroidogenesis; however, no genetic studies to determine the significance of autophagy exist.

To investigate the function of autophagy in the ovary and testis, …

Investigation Of Cardiac Electrophysiology In Human Ventricular Tissue, Kathleen Brownson

Theses and Dissertations--Biomedical Engineering

Individuals with cardiomyopathy are at higher risk to die from sudden cardiac arrest than those with non-failing (NF) hearts. This study examined the differences in electrical properties of failing and NF human hearts in terms of cardiac memory through explicit control of diastolic intervals in a sinusoidal fashion, restitution of action potential duration (APD) through standard and dynamic pacing protocols, maximum rate of depolarization and APD alternans. Recordings of transmembrane potentials were made in tissues extracted from patients with heart failure and one donor NF heart. Computational simulations were performed using the O’Hara Rudy model for generating surrogates of control …

Earthquake Risk In Indonesia: Parametric Contingent Claims For Humanitarian Response And Financial Institution Resiliency, Jason Hartell

Theses and Dissertations--Agricultural Economics

This dissertation explores the use of an index based contingent claims mechanism against earthquake risk in Indonesia. It focuses on time critical financing needs of international humanitarian relief organizations, and on efforts to improve the resiliency of geographically constrained financial institutions whose clientele are exposed to disaster risk. The approach uses measures of ground motion intensity as the basis for the index. The humanitarian response mechanism provides a new way for private sector partners to participate and gain visibility in their support of principled humanitarian funding. Index based contingent claims for local banks are shown to enhance their ability to …

Listeria Monocytogenes Can Utilize Both M Cell Transcytosis And Inla-Mediated Uptake To Cross The Epithelial Barrier Of The Intestine During An Oral Infection Model Of Listeriosis, Hilary Denney

Theses and Dissertations--Medical Sciences

The invasive pathways, InlA- and InB-mediated uptake and M cell transcytosis, that Listeria monocytogenes uses to invade the intestine have mainly been studied using infection models that do not truly replicate what occurs during a natural infection. Recently, our lab has developed an oral infection model that is more physiolocally relevant to what occurs during food borne listeriosis. We have sought to evaluate the relative roles of the previously defined invasive pathways, in our oral model of infection. We have done this by utilizing an InlAmCG Lm strain that is able to bind murine E-cadherin, knockout Lm strains, ΔinlA Lm …