Digital Commons Network^™

The Role Of Viruses In Fe Recycling In The World's Oceans, Leo Poorvin

Doctoral Dissertations

Viral lysis is responsible for a significant fraction of bacterioplankton mortality in marine systems. This work shows that viral lysis of both heterotrophic bacterial and autotrophic cyanobacterial plankton releases iron (Fe) at a greater rate than is released from unlysed cells. These studies also show that the Fe released is bound to organic ligands, these ligands are not siderophores, and that these ligands have Fe binding stability constants similar to organic ligands found in seawater. Further, these studies have shown Fe released via viral lysis to be highly bioavailable to a range of model marine plankton and may potentially satisfy …

Understanding Immune Response In Mycobacterium Ulcerans Infection, Sarojini Adusumilli

Doctoral Dissertations

Buruli ulcer is a necrotizing skin infection and is the third most important mycobacterial disease in immune competent individuals after tuberculosis and leprosy in humid tropical countries. The causative agent Mycobacterium ulcerans is unlike other mycobacterial pathogens in that it appears to maintain an extracellular location during infection. Another unusual feature of the bacterium is that it is the only mycobacterium known to produce a dermo-necrotic polyketide toxin called mycolactone. A single Buruli ulcer, which can cover 15% of a person's skin surface, contains huge numbers of extracellular bacteria. The infection is characterized by massive necrosis at the site of …

Studies On The Role Of Specific Residues Of The Saccharomyces Α-Factor Pheromone Receptor (Ste2p) In The Inactive And Active State, Yong-Hun Lee

Doctoral Dissertations

G protein-coupled receptors (GPCRs) are a class of integral membrane receptor proteins that are characterized by seven-transmembrane (7TM) domains connected by intracellular and extracellular loops, an extracellular N-terminus, and an intracellular C-terminus. To date more than 1000 GPCRs have been identified, and these proteins recognize neurotransmitters, sensory molecules and chemotactic agents. These receptors are involved in the control of many aspects of metabolism and play important roles in diverse processes such as pain perception, growth and blood pressure regulation, and viral pathogenesis. Therefore, these proteins became important target for therapeutic agents and recent reports indicate that nearly 40% of drugs …

Examining Consumer Pre-Purchase Deliberation Process In An Online Marketplace, Hyung Chul Park

Doctoral Dissertations

The research objective of this study was to examine the consumer pre-purchase deliberation process in an online marketplace. Especially, examining the role of extrinsic quality (website-related quality), intrinsic quality (business operation-related quality), reputation of the retailer (other consumers’ opinions), attitude toward the retailer, and intention to transact with the retailer in an online marketplace context was main purpose of this study.

To collect the data, extensive online survey was performed. The data were analyzed through structural equation modeling test.

Findings revealed that there are significant positive relationships among extrinsic quality, intrinsic quality, reputation of the retailer, attitude toward the retailer, …

Analysis Of Vehicle Use Patterns During Military Field Exercises To Identify Potential Roads, Chunxia Wu

Doctoral Dissertations

Military training is an intensive land use and can cause negative environmental effects. Many studies conducted under Integrated Training Area Management (ITAM) for quantifying the impact resulted from the military training exercise found that off-road vehicular activities during training exercises cause the major impact to the training land. Vehicle land use patterns at a certain location affect the impact severity: concentrated and repeated traffic create more serious damage to the land compared to the dispersed offroad vehicle movements. Those areas heavily disturbed by off-road traffic may require a longer period of time or special treatments for the land to return …

High Resolution X-Ray And Neutron Crystallographic Studies Of Escherichia Coli Dihydrofolate Reductase, Brad C. Bennett

Doctoral Dissertations

Dihydrofolate Reductases (DHFRs) have been identified in nearly every proteome and are essential for most biosynthetic pathways involving one-carbon transfer reactions due to their recycling of tetrahydrofolate (THF). They catalyze the NADPH-dependent reduction of dihydrofolate (DHF), producing THF. Inhibition of DHFR ultimately depletes cellular pools of THF; causing a reduced supply of thymine nucleotides for DNA synthesis, resulting in genomic instability and cell death. Therefore, DHFRs remain important drug targets in antimicrobial and chemotherapeutic treatments. Despite exhaustive investigation of E. coli chromosomal DHFR, controversy persists over the dynamics of regulatory loops (the Met20, the βF-βG, and the βG-βH) and the …

Physical Activity Of Older Adults Residing In Different Levels Of Care, Randall Joseph Bergman

Doctoral Dissertations

This study compared the physical activity and functional levels of older adults residing in retirement (RH), assisted-living (AL) and nursing homes (NH). The StepWatch Step Activity Monitor3 (SW) pedometer was used to collect the number of steps taken during one day of activity. Activities of daily living (ADL) and instrumental activities of daily living (IADL) surveys were completed to measure functional status in terms of ADL problems and impairments. The sample consisted of thirty-seven older adults (17 RH, 8 AL, 12 NH, 71 – 94 years old) who wore the SW on the right ankle during a full day of …

Father Perspectives On The Relationship Between Family-Centered Practices And Empowerment Outcomes In Early Intervention, William Bryan Higgins

Doctoral Dissertations

The purpose of the present investigation was to explore fathers’ perceptions of family-centered practices in early intervention services and to examine how these practices influence fathers’ feelings of empowerment. Literature reviewed examined the family-centered approach to service delivery and empowerment outcomes, especially in early intervention programs. In addition, a brief discussion of fatherhood research was presented in an effort to inform potential hypotheses and discussion.

The current study was conducted as part of the Pathways to Family Empowerment Project whose purpose is to evaluate the family-centered model of service delivery in Tennessee’s Early Intervention System (TEIS). The data collected were …

Ligand Binding Studies In R67 Dihydrofolate Reductase And The Evaluation Of The Anion-Quadrupole Interaction At A Quantum Mechanical Level, Michael Robert Jackson

Doctoral Dissertations

Dihydrofolate reductases (DHFR) are important, ubiquitous enzymes catalyzing the hydride transfer from NADPH to dihydrofolate and producing the tetrahydrofolate intermediate that is essential for many metabolic processes, particularly for its role in DNA synthesis. R67 DHFR is a plasmid encoded enzyme that confers resistance to the antibiotic drug trimethoprim. This enzyme is active as a homotetramer. The active site pore possesses 222 symmetry as a result. This symmetry gives rise to a different mechanism by which it binds its ligands. There are potentially four symmetry related binding sites, but various studies have indicated only three possible combinations that include: two …

Ruffed Grouse Habitat Use, Reproductive Ecology, And Survival In Western North Carolina, Benjamin Colter Jones

Doctoral Dissertations

Ruffed grouse populations are lower in the Appalachians compared to the Great Lakes states, the geographic core of grouse distribution. Theories to explain lower numbers in the Appalachians include inadequate foods, lower reproduction, lower survival, and loss of habitat. To provide insight into ruffed grouse ecology in the Appalachians, habitat use, reproduction, and survival were studied on Nantahala National Forest in western North Carolina. Radiotagged grouse (n = 276) were monitored through the year. Seasonal 75% kernel home ranges (n = 172) averaged 15–59 ha across sexes, ages, and seasons. Home range size was related to habitat with …

Microcapsule Biosensors Based On Competitive Binding And Fluorescence Resonance Energy Transfer Assays, Swetha Chinnayelka

Doctoral Dissertations

Fluorescent sensing systems offer the potential for minimally invasive monitoring with implantable devices, but they require carrier technologies that provide suitable immobilization, accessibility, and biocompatibility while maintaining adequate response characteristics. Towards the development of this goal, a general design of a biosensor with the capability of detecting different metabolites was investigated. The approach is based on the encapsulation of a competitive binding assay in microcapsules and monitoring the changes in fluorescence resonance energy transfer (FRET) in the presence of analyte. To experimentally demonstrate this type of sensing system, glucose was chosen as the model target analyte. The design, fabrication, and …

Molecular Mechanism Of Caffeine-Induced Expression Of Two Cytochrome P450 Genes, Cyp6a2 And Cyp6a8, In Drosophila Melanogaster, Srividya Bhaskara

Doctoral Dissertations

Cytochrome P450 monooxygenases or CYPs comprise a large family of enzymes that are found in all classes of living organisms, from bacteria to man. These enzymes are involved in the metabolism of many endogenous and xenobiotic (foreign) compounds. In insects, CYPs confer resistance to various insecticides, and resistance-associated overexpression of multiple CYP genes in resistant insects is a common phenomenon. In Drosophila, multiple Cyp genes including Cyp6a2 and Cyp6a8 show higher level of expression in resistant strains than in the susceptible ones. To date, molecular basis of CYP gene overexpression has not been examined in detail. Barbiturate compounds such …

Acupuncture Use For Pain As Compared To Other Complementary And Alternative Medicine And Conventional Medicine, Elizabeth Susan Mcgrady

Doctoral Dissertations

The purpose of the study was to determine the factors associated with the use of acupuncture for pain and to compare these factors to the use of other complementary and alternative medicine (CAM) and conventional medical services. The treatment of pain is expensive. In addition, use of surgery and medication increases risk of medical errors, complications, side effects and addiction. Clinical trials of acupuncture for pain have demonstrated results at least as effective as conventional treatments with negligible side effects and complications. Only 4% of the United States population has used acupuncture. The healthcare field is studying means to predict …

Nonindigenous Herpetofauna Of Florida: Patterns Of Richness And Case Studies Of The Impacts Of The Tadpoles Of Two Invasive Amphibians, Osteopilus Septentrionalis And Bufo Marinus, Kevin G. Smith

Doctoral Dissertations

Although invasive species are considered to be a significant threat to native biodiversity, the impacts of very few nonindigenous species are well known. In this dissertation I describe the results of several studies evaluating the impacts of the presence of nonindigenous amphibians and reptiles in Florida. I conducted an analysis to assess the patterns and effects on biodiversity of the establishment of nonindigenous amphibians and reptiles in Florida at the county level. The richness of the 40 established nonindigenous amphibians and reptiles is not distributed evenly across the state, but instead is significantly greater in the southern part of the …

The Oligopeptide Transport Family: Informatic And Experimental Characterization, Amy Marie Wiles

Doctoral Dissertations

All cells require means to obtain nutrients, dispose of waste, and communicate with other cells. One mechanism fulfilling these requirements is active transport, and many permeases in proteomes provide this function. One family of permeases is the Oligopeptide Transport (OPT) family, which is characterized by transporting tetra/penta-peptides across the plasma membrane. In this research, an informatic approach was taken to identify 103 family members, all from plant or fungal species with sequence homology to OPTs of known function.

Eighteen conserved motifs were identified in these homologues. Using several computational algorithms and multiple sequence alignment, 12 transmembrane domains have been identified …

Genetic Mapping Of Quantitative Trait Loci Conditioning Protein Concentration And Quality, And Other Seed Characteristics In Soybean [Glycine Max (L.) Merrill], Dilip Raj Panthee

Doctoral Dissertations

Soybean [Glycine max (L.) Merr.] is grown for its high oil and protein concentration, which may be used in a wide array of industries throughout the world. It contributes about 15 billion dollars annually to the US economy. Focusing on protein concentration and quality, I was interested to discover genomic regions as quantitative trait loci (QTL) associated with nitrogen accumulation during reproductive stages, protein concentration, storage protein fractions, amino acid composition, seed size, oil content, and agronomic traits. A population of 101 F₆-derivedrecombinant inbredlines (RIL) created from a cross of N87-984-16 x TN93-99 were used to achieve …

The Relationship Between Spirituality And The Health Of College Students In A University Setting, Linda Wyatt Nelms

Doctoral Dissertations

The purpose of this study was to examine the relationship between spirituality and the health of college students. Undergraduate students enrolled in Personal Health and Wellness classes at The University of Tennessee were selected to participate in the study. Two-hundred twenty-one students were administered two instruments: The College Student Appraisal of Risks Survey (The CARS) and the Spirituality Scale (SS). The CARS instrument was used to obtain descriptive statistics and specific health risk factors relating to the health of college students. The SS instrument was used to obtain the student’s self-reported level of spirituality. Based upon a thorough literature review, …

Frequent Pattern Finding In Integrated Biological Networks, Xinxia Peng

Doctoral Dissertations

Biomedical research is undergoing a revolution with the advance of high-throughput technologies. A major challenge in the post-genomic era is to understand how genes, proteins and small molecules are organized into signaling pathways and regulatory networks. To simplify the analysis of large complex molecular networks, strategies are sought to break them down into small yet relatively independent network modules, e.g. pathways and protein complexes.

In fulfillment of the motivation to find evolutionary origins of network modules, a novel strategy has been developed to uncover duplicated pathways and protein complexes. This search was first formulated into a computational problem which finds …

Mass Spectrometry-Based Proteomics For Studying Microbial Physiology From Isolates To Communities, Nathan Christopher Verberkmoes

Doctoral Dissertations

With the advent of whole genome sequencing, a new era of biology was ushered in allowing for “systems-biology” approaches to characterizing microbial systems. The field of systems biology aims to catalogue and understand all of the biological components, their functions, and all of their interactions in a living system as well as communities of living systems. Systems biology can be considered an attempt to measure all of the components of a living system and then produce a data-driven model of the system. This model can then be used to generate hypotheses about how the system will respond to perturbations, which …

Systematics Of The North American Plums (Prunus Subgenus Prunus Section Prunocerasus; Rosaceae), Joey Thomas Shaw

Doctoral Dissertations

The North American plums (Prunus subgenus Prunus section Prunocerasus; Rosaceae) are a closely related group with approximately 17 commonly recognized species and lesser taxa. They are infamous for their very poor development of reproductively isolating barriers and most are interfertile in many combinations. This interfertility blurs nearly all morphologically-based taxonomic boundaries. Even still, geographically related morphological variation exists and when intermediates are ignored several taxa may be seen as being reasonably different from one another with respect to both morphology and ecology. Additionally, the ranges of most of the North American plum taxa overlap with the ranges of …

In Situ Biostimulation Of Uranium Reducing Microorganisms At The Old Rifle Umtra Site, Yun-Juan Chang

Doctoral Dissertations

Bioremediation is a promising strategy for cleaning up heavy metal and radionuclide contamination. Nutrient or electron donor amendment is an increasingly accepted practice used to stimulate the growth of microorganisms capable of immobilizing dissolved uranium in situ, but there is scant understanding of the systematic effects of nutrient addition on indigenous microbial populations or the progress of the bioremediation. Successful implementation of metal and radionuclide bioremediation in heterogeneous environments requires an understanding of the complex microbial and geochemical interactions that influence the redox speciation and mobility of toxic metals.

The major challenge in microbial ecology and biogeochemistry is to …