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Structural Basis Of Substrate Recognition In Thimet Oligopeptidase And Development Of Nanoparticles For Therapeutic Enzyme Delivery, Jonathan Mark Wagner

Theses and Dissertations--Molecular and Cellular Biochemistry

Neuropeptidases are responsible for degradation of signaling peptides in the central nervous system and periphery. Some neuropeptidases have also been shown to play a role as part of the cell’s hydrolytic machinery responsible for breaking down proteins and peptides into amino acids, and these enzymes therefore influence small peptide availability for antigen presentation. A better understanding of how neuropeptidases recognize their substrates could lead to therapeutics that modulate the activity of these important enzymes. Alternatively, re-engineering these enzymes to selectively hydrolyze undesirable peptides could make them attractive as therapeutics themselves. A key question in understanding the activity of these enzymes …

Investigating The Ped Protein And Its Effect On Translational Control In Drosophila Melanogaster Spermatogenesis, David C. Keesling

Theses and Dissertations--Biology

Inactive mutants of the ped gene cause two phenotypes in Drosophila melanogaster: male sterility and the early translation of DHODH within spermatogenesis. Investigation of the PED amino acid sequence revealed an OTU domain and an ubiquitin interacting motif, suggesting that it is a member of the otubain sub-family of de-ubiqutinating enzymes. To test this, the putative active cysteine residue was mutated. Results show that this single cysteine residue is required for ped to confer male fertility. Purified wild type PED was also used to carry out in vitro deubiquitinating assays. These assays failed to show any ability for PED …

The Role Of Syntaxin And Tomosyn In Platelet Secretion, Shaojing Ye

Theses and Dissertations--Molecular and Cellular Biochemistry

Platelet secretion is important for hemostasis and thrombosis. The components released are also involved in atherosclerosis, inflammation, angiogenesis, and tumor growth. Though the exact mechanism(s) of platelet secretion is still elusive, accumulating evidence demonstrates that SNAREs (Soluble N-ethylmaleimide Sensitive Factor Associated Receptor) and their regulatory partners are critical for platelet exocytosis. Formation of a trans-bilayer complex composed of one v-SNARE (i.e. VAMPs) and two t-SNAREs (i.e. syntaxin and SNAP-25-type) is minimally required for membrane fusion. Regulatory proteins control the rate and specificity of the complex assembly. VAMP-8 and SNAP-23 (a SNAP-25-type t-SNARE) are clearly important; however, the …

When Molecules And Morphology Clash: Revisiting Species Tree Reconstruction Of Ambystomatid Salamanders Using Multiple Nuclear Loci, Joshua Steven Williams

Theses and Dissertations--Biology

The analysis of diverse data sets can yield different phylogenetic estimates that challenge systematists to explain the source of discordance. The Ambystomatidae are a classic example of this phylogenetic conflict. Previous attempts to resolve the ambystomatid species tree using allozymic, morphological, and mitochondrial sequence data have yielded different estimates, making it unclear which data source best approximates ambystomatid phylogeny. We present the first multi-locus DNA sequencebased phylogenetic study of the Ambystomatidae. Because independent loci can contain discordant gene tree histories, concatenating unlinked loci into a single data matrix can lead to strongly supported and erroneous results. Therefore, we utilized a …

The Effects Of Spatial Configuration Of Populations On The Maintenance Of The Sexes In A Clonal Organism, Christopher Stieha

Theses and Dissertations--Biology

Despite the two-fold advantage to asexual reproduction and its prevalence in a variety of organisms, sexual reproduction is prevalent across all taxa. The maintenance of two sexes is required to ensure genetic diversity and to prevent “evolutionary dead ends,” especially in clonal organisms. Many mechanisms have been proposed for the maintenance of two sexes, ranging from environmental variation and stochasticity, parasites and predators, and mutation rates. Spatial configuration, the size and location of populations with respect to other populations, can allow two competitors to coexist when one would normally be lost. This is especially important when the two competitors are …

Ecosystem Impacts Of The Invasive Shrub Lonicera Maackii Are Influenced By Associations With Native Tree Species, Megan Marie Poulette

Theses and Dissertations--Biology

Invasive species are significant drivers of global environmental change, altering the stability and functioning of numerous ecosystems. The exotic shrub Lonicera maackii is an aggressive invader throughout much of the eastern United States. While much is known about its population and community impacts, little is known about effects on ecosystem processes.

This dissertation documents changes in ecosystem processes associated with L. maackii growing beneath three native tree species (Fraxinus quadrangulata, Quercus muehlenbergii, Carya ovata) in a savanna in Kentucky. Like many invasive plants, L. maackii litter decomposed and lost nitrogen (N) rapidly, especially in comparison with …

Empirical And Conceptual Approaches To Life-History Trade-Offs: The Size And Number Of Offspring In Broods Of A Parasitoid Wasp, Yoriko Saeki

Theses and Dissertations--Biology

Trade-offs in resource allocation underlie key life history traits of organisms. My dissertation focuses on the size-number trade-off in clonal broods of offspring using the polyembryonic wasp, Copidosoma bakeri parasitizing immature stages of the moth Agrotis ipsilon. I aim to characterize responses of wasp brood size and individual body mass by manipulating the environments in order to understand the allocation pattern in the size number trade-off. In reviewing the functional forms of trade-off relationships in relation to resource constraints, I distinguish among three main trade-off types based on graphical representations of the relationship between the trade-off variables: linear, convex …

Ecology Of Mating Patterns And Sexual Selection In Dickcissels Breeding In Managed Prairie, Bridget Frances Sousa

Theses and Dissertations--Biology

Males of many species have elaborate phenotypes that are absent in females and that are thought to be the result of sexual selection. Sexual selection requires: (i) variance in male mating success, (ii) variation in male phenotype, and (iii) covariation between male mating success and male phenotype. Environmental conditions influence these factors, and management practices that alter environmental conditions have the potential to shape mating patterns and sexual selection. I investigated the hypothesis that the frequency of fire, used to manage tallgrass prairie, affects the mating patterns and process of sexual selection in the organisms breeding in managed prairies.

I …

The Ecological And Evolutionary Effects Of Endocrine Disrupting Compounds On Sexually Selected Traits In Male Guppies, Kausalya Shenoy

Theses and Dissertations--Biology

Male mating signals convey important mate-quality information to females and are regulated by androgens. Endocrine disrupting compounds (EDCs) are chemicals that interfere with proper hormonal functioning in exposed animals, causing altered hormone levels and resulting in changed reproductive characteristics, including mating signals. Altered signals can have ecological implications by influencing population and community dynamics and evolutionary implications via trans-generational reduction in signal reliability leading to reduced preference and eventual loss of the signal trait. I examined the effects of exposure to environmentally relevant concentrations of atrazine, a widely used herbicide and EDC, on mating signals and behaviors in male guppies, …

Improving Communication Skills Among Nursing Students: Assessing The Comfort Curriculum As An Intervention, Rachel Steckler

Theses and Dissertations--Communication

Effective communication is just one of the many skill sets nursing students must master to be effective in their field. A nurse’s role goes far beyond that of medical care. In addition, Today’s nurses should be equipped with a working knowledge of medical management, communication skills, ethical/legal issues, end-of-life care, and team collaboration, among others (e.g., Ferrell, Dahlin, Campbell, Paice, Malloy, & Virani, 2007).Wittenberg-Lyles, Goldsmith, Sanchez-Reilly, and Ragan (2010) contend nurses need to have specialized training protocols focused on developing effective communication skills . The current study employed one such protocol, the COMFORT curriculum, as a tool to teach nursing …

Adult Bmi Change And Risk Of Colon Cancer In Postmenopausal Women, Lyla Blake-Gumbs, Zhengyi Chen, Cheryl L. Thompson, Nathan A. Berger, Thomas C. Tucker, Li Li

Markey Cancer Center Faculty Publications

Purpose. We recently reported an association of adult BMI change with colon cancer risk. Here, we sought to further explore this association with respect to postmenopausal HRT use in a larger study population. Methods. We included 1,457 postmenopausal women participating in an ongoing population-based case-control study of colon cancer. Results. We confirmed a previously reported association of adulthood weight gain and increased risk of colon cancer: compared to those with <5 kg/m² change of BMI, women who reported moderate (5–10 kg/m²) and large (>10 kg/m²) BMI changes since their 20s had OR estimates …

Metallic Patterning Using An Atomic Force Microscope Tip And Laser-Induced Liquid Deposition, Carlos Andrés Jarro Sanabria

Theses and Dissertations--Electrical and Computer Engineering

The development of nanoscale patterns has a vast variety of applications going from biology to solid state devices. In this research we present a new direct patterning technique in which laser photoreduction of silver from a liquid is controlled by a scanning atomic force microscope tip. While pursuing the formation of patterns using the plasmonic field enhancement of an electromagnetic wave incident on a metallic Atomic Force Microscope (AFM) tip, our group discovered that contrary to expectations, the tip suppresses, rather than enhances, deposition on the underlying substrate, and this suppression persists in the absence of the tip. Experiments presented …

The Effect Of Integrated Weed Management Strategies On Weed Populations And Biomass, Pasture Productivity, Economic Returns, And Forage Quality With And Without Grazing, Joshua Allen Tolson

Theses and Dissertations--Plant and Soil Sciences

Field studies examined the strategies of mowing, herbicide, fertility, and all combinations on tall ironweed populations, weed biomass, pasture yield, grazing, economics, and forage quality at three Kentucky locations. Mowing was performed in July 2008 and 2009, herbicide applied in August 2008, and fertilizer applied in September 2008 and 2009 at all locations. Weed populations were measured in 2008, 2009, and 2010, and forage and weed biomass collected in May or June of 2009 and 2010. Herbicide treatments reduced weed biomass at all locations, and reduced tall ironweed stems by 64% or greater in 2009 at all locations. Weed biomass …

Enantioselective Demethylation: The Key To The Nornicotine Enantiomeric Composition In Tobacco Leaf, Bin Cai

Theses and Dissertations--Plant and Soil Sciences

Nicotine and nornicotine are the two main alkaloids that accumulate in Nicotiana tabacum L. (tobacco), and nornicotine is the N-demethylation metabolite of nicotine. Nicotine is synthesized in the root, and probably primarily in the root tip. Both nicotine and nornicotine exist as two isomers that differ from each other by the orientation of H atom at the C-2' position on the pyrrolidine ring. (S)-nicotine is the dominant form in tobacco leaf and the enantiomer fraction of nicotine (EF_nic), the fraction of (R)-enantiomer over the total nicotine, is approximately 0.002. Despite considerable efforts to elucidate nicotine and nornicotine …

Evaluation Of Vascular Changes In Cattle Relative To Time-Off Endophyte-Infected Tall Fescue, Jessica R. Bussard

Theses and Dissertations--Plant and Soil Sciences

Twenty-four steers were grazed on endophyte (Neotyphodium coenophialum)-infected [[Lolium arundinaceum (Schreb.) Darbysh]; E+] tall fescue (TF) and exposed to ergot alkaloids for an 106-d grazing period. Cattle were removed from pasture, placed in dry lots, and fed a non-toxic diet to evaluate changes in vascular contraction relative to time-off E+ TF pasture. Lateral saphenous veins (SV) were biopsied from steers at 0-, 21-, 42-, and 63-d off TF pasture and from 6 control steers at 0- and 63-d off bermudagrass (BG) pasture. To evaluate contractile response, biopsied SV were exposed to increasing concentrations of ergotamine in a multimyograph. Cross-sectional scans …

Evaluating Streamside Management Zone Effectiveness In Forested Watersheds Of The Cumberland Plateau, Emma Lela Witt

Theses and Dissertations--Plant and Soil Sciences

Headwater stream systems are important components of the overall hydrologic system. Forestry best management practices (BMP) are effective at minimizing non point source pollution from forest harvesting activities. Streamside management zones (SMZ) are one BMP used to protect surface water quality by maintaining shade near streams, filtering runoff, and minimizing soil disturbance near streams. An evaluation of BMP effectiveness on the watershed scale was conducted at the University of Kentucky’s Robinson Forest. Six watersheds were harvested using a two-age deferment harvest with one of three SMZ configurations applied to each watershed. Two unharvested watersheds served as controls.

Treatment 1 was …

Method Development For Detecting And Characterizing Manufactured Silver Nanoparticles In Soil Pore Water Using Asymmetrical Flow Field-Flow Fractionation, Annie R. Whitley

Theses and Dissertations--Plant and Soil Sciences

Recent advances in nanotechnology have led to the production of materials with nanoscale dimensions (nm) and properties distinctly different from their bulk (>100 nm) counterparts. With increased use, it is inevitable that nanomaterials will accumulate in the environment and there is concern that the novel properties of nanomaterials could result in detrimental environmental and human health effects. In particular, there has been concern recently regarding the use of silver (Ag) based nanomaterials as antimicrobial agents in consumer and medical products. Current regulations dealing with the discharge of metals into the environment are based on total concentrations with no consideration …

Minority Stress And Physical Health In Lesbians, Gays, And Bisexuals: The Mediating Role Of Coping Self-Efficacy, Fowler Nicholas Denton

Theses and Dissertations--Educational, School, and Counseling Psychology

Mental health issues have been the primary focus of much of the health research concerning lesbian, gay, and bisexual (LGB) individuals over the previous decade. Studies have demonstrated that LGB individuals experience psychological distress due to prejudice and discrimination (Lewis, Derlega, Berndt, Morris, & Rose, 2002; Meyer, Schwartz, & Frost, 2008; Rostosky, Riggle, Horne, & Miller, 2009). Health researchers have not given the physical health of LGB individuals the same level of attention (Dibble, Eliason, & Christiansen, 2007). The Gay and Lesbian Medical Association (GLMA; 2001) asserted that little was known about LGB physical health disparities and called for more …

Factors Influencing Women’S Psychological Well-Being Within A Positive Functioning Framework, Krista Moe

Theses and Dissertations--Educational, School, and Counseling Psychology

Women suffer a high prevalence rate of several mental disorders. National U.S. data (N = 9,282) shows that 23.4% of women meet the criteria for an anxiety disorder, 8.6% for depression, and 11.6% for a mood disorder (Kessler et al., 2005). Compared to men, women are two times more likely to be depressed (Lewinsohn, Rhode, Seeley, & Baldwin, 2001) and two to three times more likely to suffer from anxiety disorders such as panic disorders, phobias, obsessive compulsive disorders, and Posttraumatic Stress (Kessler et al., 2005). Due to experiencing a high number of mental disorders, women’s psychological well-being (PWB) …

Oxidative Stress And Down Syndrome: A Route Toward Alzheimer-Like Dementia, Marzia Perluigi, D. Allan Butterfield

Chemistry Faculty Publications

Down syndrome (DS) is one of the most frequent genetic abnormalities characterized by multiple pathological phenotypes. Indeed, currently life expectancy and quality of life for DS patients have improved, although with increasing age pathological dysfunctions are exacerbated and intellectual disability may lead to the development of Alzheimer's type dementia (AD). The neuropathology of DS is complex and includes the development of AD by middle age, altered free radical metabolism, and impaired mitochondrial function, both of which contribute to neuronal degeneration. Understanding the molecular basis that drives the development of AD is an intense field of research. Our laboratories are interested …

How A Silent Mutation Suppresses The Activity And Iron Incorporation In Superoxide Dismutase, Xiaonan Mei

Theses and Dissertations--Chemistry

A mutation (CTG to TTG) of FeSOD gene was found in Escherichia coli. Since they both encode leucine, it is a silent mutation. Site-­‐directed mutagenesis was applied to correct the mutation, and the mutant FeSOD (before gene correction) and wild type FeSOD (after gene correction) were purified. The FeSODs from the two genes were Characterized using different assays and spectroscopic methods including EPR and CD. The requirement for the rare codon TTG may result in slowed translation and heavy demand on a scarce tRNA. Cultures expressing wild type FeSOD are better able to grow for long times after addition of …

Investigations Into Modulation Of Brain Oxidative Stress By Various Interventions, Jessica Lynn Harris

Theses and Dissertations--Chemistry

In this thesis study we examined glycogen synthase kinase-3β (GSK-3β) and its effects over Nrf2 and Pin 1 as it relates to Alzheimer’s disease (AD). AD is a neurodegenerative disease characterized by a prolonged high oxidative environment. Transcription factor Nrf2 is vital in the brain’s defense against oxidative insults through its up-regulation of over 100 antioxidants. Depletion of the brain’s antioxidant defense system results in intolerance to an oxidative environment, contributing to the progression of AD. The regulatory Pin 1 protein promotes cellular homeostasis, and when down-regulated results in increased deposits of neurofibrillary tangles (NFTs) and amyloid-β (Aβ) plaques, the …

Bifunctional Bisphosphonates For Delivering Biomolecules To Bone, Jivan N. Yewle

Theses and Dissertations--Chemistry

Active targeting with controlled delivery of therapeutic agents to bone is an ideal approach for treatment of several bone diseases. Since bisphosphonates (BPs) are known to have high affinity to bone mineral and are being widely used in treatment of osteoporosis, they are well-suited for drug targeting to bone. For this purpose, bifunctional hydrazine-bisphosphonates (HBPs) with spacers of various lengths and lipophilicity were synthesized and studied. Crystal growth inhibition assays demonstrated that the HBPs with shorter spacers bound more strongly to bone mineral, hydroxyapatite (HA), than did alendronate. HBPs were also demonstrated to be non-toxic to MC3T3-E1 pre-osteoblasts. The targeted …

Design, Synthesis, And Anticancer Activity Of Ruthenium Complexes, Brock S. Howerton

Theses and Dissertations--Chemistry

Ruthenium complexes show promise as light activated photodynamic therapy (PDT) prodrugs. Strained octahedral complexes were synthesized that produce a cytotoxic species upon light activation. pUC19 DNA damage in vitro experiments were carried out to determine the type of damage observed. In vivo cell experiments were carried out on the non-small lung cancer A549 cell line to determine the phototherapeutic window of the synthesized complexes. One mechanism of drug resistance via elevated levels of glutathione was addressed through in vitro binding studies carried out with UV-Vis spectroscopy and in vivo glutathione titrations in the A549 cell line. Several complexes were shown …

Investigations Of Oxidative Stress Effects And Their Mechanisms In Rat Brain After Systemic Administration Of Ceria Engineered Nanomaterials, Sarita S. Hardas

Theses and Dissertations--Chemistry

Advancing applications of engineered nanomaterials (ENM) in various fields create the opportunity for intended (e.g. drug and gene delivery) or unintended (e.g. occupational and environmental) exposure to ENM. However, the knowledge of ENM-toxicity is lagging behind their application development. Understanding the ENM hazard can help us to avoid potential human health problems associated with ENM applications as well as to increase their public acceptance. Ceria (cerium [Ce] oxide) ENM have many current and potential commercial applications. Beyond the traditional use of ceria as an abrasive, the scope of ceria ENM applications now extends into fuel cell manufacturing, diesel fuel additives …

Removal Of Arsenic(Iii) From Water With A New Solid-Supported Thiol, Partha Jana

Theses and Dissertations--Chemistry

Arsenic is a highly toxic, easily transportable and widespread contaminant in groundwater throughout the world. Arsenic causes acute toxicity by disrupting biological functions. In groundwater arsenic concentrations can reach up to a few milligrams per liter. Current regulations on arsenic content in drinking water are becoming more stringent and require the standard to be reduced to a few parts per billion. Arsenic exists as oxyanions in aqueous solution in either trivalent or pentavalent oxidation states depending on the oxidation-reduction potential and pH of the medium. Several treatment methods are available for removing arsenic from water. However, cost, operational complexity of …

Biosensing Systems For The Detection Of Bacterial Quorum Sensing Molecules: A Tool For Investigating Bacteria-Related Disorders And Food Spoilage Prevention, Nilesh G. Raut

Theses and Dissertations--Chemistry

Quorum sensing enables bacteria to communicate with bacteria of the same or different species, and to modulate their behavior in a cell-density dependent manner. Communication occurs by means of small quorum sensing signaling molecules (QSMs) whose concentration is proportional to the population size. When a QSM threshold concentration is reached, certain genes are expressed, thus allowing control of several processes, such as, virulence factor production, antibiotic production, and biofilm formation. Not only many pathogenic bacteria are known to produce QSMs, but also QSMs have been identified in some bacteria-related disorders. Therefore, quantitative detection of QSMs present in clinical samples may …

Protein Based Biomimetic Approachs To Surface Hemocompatibility And Biocompatibility Enhancement, Matthew Thomas Dickerson

Theses and Dissertations--Chemical and Materials Engineering

T. pallidum can survive a primary immune response and continue growing in the host for an extended period of time. T. pallidum is thought to bind serum fibronectin (FN) through Tp0483 on the surface to obscure antigens. A Tp0483 fragment (rTp0483) was adsorbed onto functionalized self-assembled monolayers (SAMs) with FN. FN capture by adsorbed rTp0483 depended greatly on surface chemistry with COO- groups being best for FN binding. Hemocompatibility was determined by analysis of plasma protein adsorption, intrinsic pathway activation, and platelet activation. rTp0483+FN bound an equal or lesser amount of fibrinogen (Fg), human serum albumin (HSA), and factor XII …

Fabrication Of An Epithelial Cell-Based Ion-Selective Electrode And Its Application For Use As Alternative Tumor Angiogenesis Assay, Christina Nicole Simmons

Theses and Dissertations--Chemical and Materials Engineering

Previous studies have provided evidence that endothelial cell-based potassium ion selective electrodes possess the ability to quantify substances that have permeability-altering effects on those endothelial cells. The capability of these so-called biosensors to detect elevated concentrations of certain chemical agents found following tumor formation make them useful in the application as an alternative tumor angiogenesis assay. In this study an epithelial cell line, human colon adenocarcinoma epithelial cells (Caco-2), was used to fabricate membranes that were used to test concentrations of these chemical agents, known as cytokines, mimicking the concentrations that have been observed in the serum of healthy individuals …

Biodegradable Hydrogels And Nanocomposite Polymers: Synthesis And Characterization For Biomedical Applications, Ashley Marie Hawkins

Theses and Dissertations--Chemical and Materials Engineering

Hydrogels are popular materials for biological applications since they exhibit properties like that of natural soft tissue and have tunable properties. Biodegradable hydrogels provide an added advantage in that they degrade in an aqueous environment thereby avoiding the need for removal after the useful lifetime. In this work, we investigated poly(β-amino ester) (PBAE) biodegradable hydrogel systems. To begin, the factors affecting the macromer synthesis procedure were studied to optimize the reproducibility of the resulting hydrogels made and create new methods of tuning the properties. Hydrogel behavior was then tuned by altering the hydrophilic/hydrophobic balance of the chemicals used in the …