Life Sciences Commons^™

Assessing The Genetic Diversity Of The Genus Viburnum Using Simple Sequence Repeats, Deborah Dean

Doctoral Dissertations

The genus Viburnum was established in 1753 by Linnaeus and is the largest genus in the Adoxaceae and consists of approximately 160 species. Viburnum species are small trees which grow throughout the temperate regions of the Northern Hemisphere (Hoch, 1995). While this genus shares little variety in fruit and flower morphology, it is diverse in many other traits. As molecular studies advance, this large genus continues to undergo reclassification. Here three SSR libraries were constructed to discern additional molecular insight into this vast genus.

Microsatellite markers were developed to characterize Viburnum on several different levels. V. dilatatum is an introduced …

Reverse Genetics Approach To Examine Myosin Xi Functions In Pollen Tube Growth, Stephanie Lin Madison

Doctoral Dissertations

Pollen tube growth is an essential aspect of plant reproduction because it is the mechanism through which non-motile sperm cells are delivered to ovules thus allowing fertilization to occur. A pollen tube is a single cell that only grows at the tip, and this tip growth depends on actin filaments. Plants encode class VIII and class XI myosins as actin-based motor proteins, of which class XI myosins are required for cell expansion in vegetative tissues.

In Arabidopsis thaliana, 6 of 13 myosin XI genes are expressed in pollen: XIA, XIB, XIC, XID, XIE, and …

Long-Term Impacts Of Tillage, Cover Crops, And Nitrogen Rates On Microbial Community Dynamics And Soil Quality Parameters Under Continuous Cotton Production In West Tennessee, Lilian Wanjiru Mbuthia

Doctoral Dissertations

Microbial communities play a central role in nutrient cycling and soil quality in agro-ecosystems. This research focused on a comparative analysis of the microbial community structure and activity of soils on long-term (31 years) continuous cotton- Gossypium hirsutum L., production in West Tennessee under conservation agricultural (CA) and conventional tillage practices that included: Nitrogen (N) fertilizer rates (N-rates) (0, 34, 67 and 101 kg N per ha); Cover crops (Hairy vetch-Vicia villosa and winter wheat- Triticum aestivum, and a No Cover control); and Tillage (Till and No-till). It was expected that microbial diversity, activity and soil quality would be …

The Dissolution Of Cellulose In Ionic Liquids - A Molecular Dynamics Study, Barmak Mostofian

Doctoral Dissertations

The use of ionic liquids for the dissolution of cellulose promises an alternative method for the thermochemical pretreatment of biomass that may be more efficient and environmentally acceptable than conventional techniques in aqueous solution. Understanding how ionic liquids act on cellulose is essential for improving pretreatment conditions and thus detailed knowledge of the interactions between solute and solvent molecules is necessary. Here, results from the first all-atom molecular dynamics simulation of an entire cellulose microfibril in 1-butyl-3-methylimidazolium chloride (BmimCl) are presented and the interactions and orientations of solvent ions with respect to glucose units on the hydrophobic and hydrophilic surfaces …

Pore Selectivity And Gating Of Arabidopsis Nodulin 26 Intrinsic Proteins And Roles In Boric Acid Transport In Reproductive Growth, Tian Li

Doctoral Dissertations

Plant nodulin-26 intrinsic proteins (NIPs) are members of the aquaporin superfamily that serve as multifunctional channels of uncharged metabolites and water. They share the same canonical hourglass fold as the aquaporin family. The aromatic arginine (ar/R) selectivity filter controls transport selectivity based on size, hydrophobicity, and hydrogen bonding with substrates. In Arabidopsis thaliana, NIP II subclass proteins contain a conserved ar/R “pore signature” that is composed of Alanine at the helix 2 position (H2), Valine/Isoleucine at the helix 5 position (H5), and an Alanine (LE1) and an invariant Arginine (LE2) at the two loop E positions. In this study, …

Computer Simulations Of Enzymes, Jianzhuang Yao

Doctoral Dissertations

Enzymes are important catalysts in living systems, and understanding catalytic mechanisms of enzymes is an important task for modern biophysics and biochemistry. Computer simulations have emerged as very useful tools for understanding how enzymes work. In this dissertation, QM/MM MD simulations were applied to study the catalytic mechanisms of several enzymes, including sedolisin, S-adenosyl-L-methionine (AdoMet)-dependent methyltransferases, and salicylic acid binding protein 2. For sedolisin, we focus on the acylation and deacylation reactions catalyzed by the enzymes. We proposed a general acid/base mechanism involving the Glu/Asp residues at the active site. MD and QM/MM free energy simulations on pro-kumamolisin show that …

Enhancement Of Chronically-Induced Breast Carcinogenesis By Combined Environmental And Dietary Carcinogens And Suppression By Dietary Agents, Lenora A. Pluchino

Doctoral Dissertations

Most breast cancers occur sporadically due to long-term exposure to low-dose carcinogens present in our environment and diet. American lifestyles involve frequent exposures to smoke, polluted air, and high temperature-cooked meats comprising multiple carcinogens, such as 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), benzo[α[alpha]]pyrene (B[α[alpha]]P), and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP). To investigate whether these carcinogens may act together to enhance breast cell carcinogenesis, we used our chronically-induced breast cell carcinogenesis model wherein we repeatedly expose non-cancerous human breast epithelial MCF10A cells to physiologically-achievable doses of carcinogens to progressively induce cellular acquisition of cancer-associated properties including reduced dependence on growth factors, anchorage-independent growth, increased cell proliferation, migration and …

Calcium And Leucine Modulation Of Airway Inflammation, Patricia Louise Brown

Doctoral Dissertations

Over the past several decades the prevalence of obesity and asthma have increased in a parallel fashion. Recent studies reported a positive relationship between the two disorders that may in fact be causal. Although the link between obesity and asthma has become widely recognized, the underlying pathophysiological connection is not elucidated. Increased markers of inflammatory and oxidative stress are present in obesity and asthma suggesting the link is immunological. The systemic inflammation observed in obesity may potentially initiate adverse affects in the airways. Previous studies have shown that consumption of dairy foods (rich in calcium and leucine) suppress 1,25-dihydroxycholecalciferol (calcitriol) …

Absorption And Utilization Of Choline And Vitamin B12 In Lactating Dairy Cows Using Different Delivery Methods, Virginia Maria Artegoitia Etcheverry

Doctoral Dissertations

Choline and vitamin B12 are essential nutrients for growth and performances of production animals. However, both nutrients are extensively degraded during digestion in the rumen. This thesis comprised three experiments. First, four cows equipped with a rumen cannula and catheters in the portal vein and a mesenteric artery received a post-ruminal bolus of: 1) cyanocobalamin (CN-CBL) alone (0.1 g) [gram], 2) CN-CBL (0.1 g) + casein (10 g) or 3) CN-CBL (0.1 g) + whey proteins (10 g). After the bolus, blood samples were taken until 24 h [hour] post-bolus. The intestinal absorption of CN-CBL was greater when the vitamin …

Knoxville Moves: Log-In And Get Mobile, Courtney Marie Monroe

Doctoral Dissertations

This dissertation evaluated 1) the efficacy of a course-based Internet-technology intervention rooted in social cognitive theory (SCT) for increasing step counts in university faculty and staff, and 2) the effect of online social support tools on step counts among adults using a randomized control trial.

Thirty-six sedentary/insufficiently active university faculty and staff participated in an eight-week, Internet-delivered walking intervention. They received an Omron HJ-720ITC pedometer, personal step goals, and access to a Blackboard LearnTM website comprised of SCTbased features. Outcomes included daily steps, social support, self-regulation, self-efficacy, and outcome expectations. Participants significantly increased their average daily steps (p < 0.001) between baseline and week 1 by 1800. A similar increase in daily steps was observed between baseline and all other intervention weeks (p < 0.001). Social support and self-regulation significantly improved (p < 0.001). These findings helped inform the design of the second study.

In this …

Investigating The Role Of A Reduced-Instruction Approach In Implicit And Explicit Motor Learning Strategies, Kevin Michael Fisher

Doctoral Dissertations

Traditional explanations of motor learning contend that skills are learned explicitly in a process in which learners accumulate declarative knowledge and progress through distinct stages of learning (e.g., Fitts & Posner, 1967). More recently, implicit approaches to instruction have been used in an attempt to bypass accumulation of explicit knowledge. Such approaches have been shown to facilitate motor learning compared to explicit instruction by enhancing skill retention and transfer under conditions involving distraction, increased pressure, or physical stress (Masters & Poolton, 2012). One method thought to invoke implicit learning involves instructions in the form of an analogy (Liao & Masters, …

Role Of Vitamin A Status And Its Catabolism In The Regulation Of Glucose And Lipid Homeostasis In Rats Under Physiological And Disease Conditions, Yang Li

Doctoral Dissertations

The increased number of individuals with metabolic diseases has become a public health concern. Vitamin A (VA, retinol) is required to maintain the general health of an individual. How VA contributes to the regulation of glucose and lipid homeostasis in normal and metabolic disease states is unclear. VA’s physiological activities are mainly mediated by its metabolite, retinoic acid (RA), which activates several transcriptional factors in the nuclear receptor super family and in turn, regulates the expression of numerous genes for macronutrient metabolism. For the RA production, retinol is first oxidized into retinal and then from retinal to RA. We hypothesize …

Evaluation Of Traits Associated With Breeding For Improved Biomass And Ethanol Yield In Switchgrass, Virginia Roseanna Sykes

Doctoral Dissertations

Switchgrass (Panicum virgatum L.) is a perennial, warm season grass that can be used as a biofuel. A greater understanding of the relationship of biomass yield and ethanol yield with disease susceptibility and morphological traits, estimation of the underlying genetic parameters of these traits, and the efficacy of selection at different maturity and under different production conditions could help breeders more effectively develop improved biofuel switchgrass cultivars. To examine these issues, three studies were performed. The first examined switchgrass leaves exhibiting low, medium, and high severity of rust symptoms, caused by infection with Puccinia emaculata. Results indicate P. …

The Role Of Nag-1 In Tumorigenesis, Kyung-Won Min

Doctoral Dissertations

This dissertation explores the nature of a divergent member of the Transforming Growth Factor-β [beta] superfamily, the non-steroidal anti-inflammatory drugs activated gene (NAG-1), as it relates to its regulation and biological activity in cancer context. Our lab has extensively studied on the molecular mechanism by which phytochemicals and NSAIDs induce apoptosis correlation with NAG-1 expression in human colorectal cancer (CRC) cells. Significant data from in vitro studies suggest that NAG-1 has an anti-tumorigenic activity which elicits apoptosis in a cyclooxygenase (COX)-independent manner in CRC cells. Indeed, NAG-1 transgenic mice developed less aberrant polyp foci (APC) compared to those of control …

Integration And Management Of Winter-Annual Cover Crops And Herbicides To Control Glyphosate-Resistant Palmer Amaranth (Amaranthus Palmeri S. Wats), Matthew Scott Wiggins

Doctoral Dissertations

The main objective of this research was to evaluate the integration of high residue winter-annual cover crops with herbicides, both preemergence and postemergence, to control glyphosate-resistant Palmer amaranth. The results of these trials indicated that winter-annual cover crops improved early-season weed suppression. However, cover crops alone or as part of an integrated weed management system including only preemergence or only postemergence herbicides was not sufficient to control of glyphosate-resistant Palmer amaranth. Therefore, winter-annual cover crops should be used in conjunction with existing weed control tactics to achieve adequate glyphosate-resistant Palmer amaranth control, where applicable.

An Epidemiological Study Of Campylobacter Populations Reveals A Selective Pressure By Roxarsone, Sean Jeffery Pendleton

Doctoral Dissertations

Whole genome sequencing (WGS) is the most discriminatory of typing methods and can provide additional information including virulence, antigen targets for vaccine development, and antimicrobial resistance profiles. The first part of this study aimed to determine the application of WGS as a genotyping method for Campylobacter by comparing WGS to two commonly used genotyping methods, Pulsed-field gel electrophoresis (PFGE) and flaA typing. Five Campylobacter strains isolated from conventional and organic poultry, and five additional isolates with published genomes were compared using the three methods. A total of 8 PFGE patterns and 8 flaA alleles were identified from the 10 strains. …

Understanding The Meiotic Roles Of Sisters Unbound In Drosophila Melanogaster, Badri Krishnan

Doctoral Dissertations

During meiosis, cohesin is required for sister chromatid cohesion and for formation of chromosome cores. Multiple processes including chromosome segregation, recombination and synaptonemal complex (SC) are dependent on cohesin. Cohesin complex consists of two SMC subunits- SMC1, SMC3 and two non-SMC subunits RAD21/REC8 in meiosis and SA. But in Drosophila, non-SMC subunits have not been shown to be required for cohesion. We have identified a gene sisters unbound, which along with previously identified ord and solo, form a group of three genes (sos) which do not have any sequence similarity to cohesins but performs functions …

Comparative Genomics Of Microbial Chemoreceptor Sequence, Structure, And Function, Aaron Daniel Fleetwood

Doctoral Dissertations

Microbial chemotaxis receptors (chemoreceptors) are complex proteins that sense the external environment and signal for flagella-mediated motility, serving as the GPS of the cell. In order to sense a myriad of physicochemical signals and adapt to diverse environmental niches, sensory regions of chemoreceptors are frenetically duplicated, mutated, or lost. Conversely, the chemoreceptor signaling region is a highly conserved protein domain. Extreme conservation of this domain is necessary because it determines very specific helical secondary, tertiary, and quaternary structures of the protein while simultaneously choreographing a network of interactions with the adaptor protein CheW and the histidine kinase CheA. This dichotomous …

Physiological Models Of Geobacter Sulfurreducens And Desulfobacter Postgatei To Understand Uranium Remediation In Subsurface Systems, Roberto Orellana

Doctoral Dissertations

Geobacter species are often the predominant Fe(III)-reducing microorganisms in many sedimentary environments due to their capacity for extracellular electron transfer. This exceptional physiological capability allows them to couple acetate oxidation to uranium (U(VI)) reduction, that is one of the most significant interactions between radionuclides and microorganisms that naturally takes place in uranium-contaminated environments. Although this process has been proposed as a promising strategy for the in situ bioremediation of uranium-contaminated groundwater, little is known about the molecular mechanisms involved in U(VI) reduction and the interaction between Geobacter and other microbial species. In the first two research chapters, this dissertation aim …

Engineering Surface Functionality Of Nanoparticles For Biological Applications, Yi-Cheun Yeh

Doctoral Dissertations

Engineering the surface functionality of nanomaterials is the key to investigate the interactions between nanomaterials and biomolecules for potent biological applications such as therapy, imaging and diagnostics. My research has been orientted to engineer both of the surface monolayers and core materials to fabricate surface-functionalized nanomaterials through the synergistic multidisciplinary approach that combine organic chemistry, materials science and biology. This thesis illustrates the design and synthesis of the surface-funcitonalized quantum dots (QDs) and gold nanoparticles (AuNPs) for the fundamental studies and practical applications. For QDs, A new class of cationic QDs with quaternary ammonium derivatives was synthesized to provide permanent …

Elucidating Cellular Signaling Pathways That Contribute To The Immunopathogenesis Of Aplastic Anemia, Christina M. Kuksin

Doctoral Dissertations

Aplastic Anemia is a rare immune mediated bone marrow failure disease that is mediated by autoreactive T cells that cause destruction to the stem, progenitor, and stromal cells in the bone marrow. Because little is known about the etiology of the disease, our lab has developed a major MHC mismatch GVHD model to examine cellular pathways in autoreactive T cells that contribute to disease. We examined three pathways that are important in T cell activation and differentiation and asked if they were important in the development of Aplastic Anemia. First, we were able to show that expression of active PKCθ …

Movements And Conservation Of The Migratory White-Eared Kob (Kobus Kob Leucotis) In South Sudan, Malik D. Marjan

Doctoral Dissertations

The annual movements of white-eared kob (Kobus kob leucotis), tiang (Damaliscus korrigum tiang), in eastern South Sudan was investigated to provided appropriate information for developing effective conservation actions for the migratory kob. Although kob is the focus of the study tiang has been included as the two migrations are ecologically linked and overlap at least in the wet season. During the 20 years of the civil war which ravaged South Sudan, the kob and tiang populations were thought to be severely hunted for food by both the combatants and local people to the extent that their …

Guanidinium-Rich Romp Polymers Drive Phase, Charge, And Curvature-Specific Interactions With Phospholipid Membranes, Michael T W Lis

Doctoral Dissertations

Protein transduction domains (PTDs) and their and their synthetic mimics are short sequences capable of unusually high uptake in cells. Several varieties of these molecules, including the arginine-rich Tat peptide from HIV, have been extensively used as vectors for protein, DNA, and siRNA delivery into cells. Despite the wide-ranging utility of PTDs and their mimics, their uptake mechanism is still under considerable debate. How the molecules are able to cross phospholipid membranes, and what structural components are necessary for optimal activity are poorly understood. This thesis explores how PTDMs interact with phospholipid membrane phase, anionic lipid content and negative Gaussian …

The Role Of Napping On Memory Consolidation In Preschool Children, Laura Kurdziel

Doctoral Dissertations

Nocturnal sleep has been shown to benefit memory in adults and children. During the preschool age range (~3-5 years), the distribution of sleep across the 24-hour period changes dramatically. Children transition from biphasic sleep patterns (a nap in addition to overnight sleep) to a monophasic sleep pattern (only overnight sleep). In addition, early childhood is a time of neuronal plasticity and pronounced acquisition of new information. This dissertation sought to examine the relationship between daytime napping and memory consolidation in preschool-aged children during this transitional time. Children were taught either a declarative or an emotional task in the morning, and …

Impact Of Surface Active Minor Components On Physicochemical Properties Of Association Colloids And Lipid Oxidation In Bulk Oil, Ketinun Kittipongpittaya

Doctoral Dissertations

Lipid oxidation is a great concern for food manufacturers and consumers as it negatively impacts not only food quality and nutritive values of food lipids, but also consumer health. Lipid oxidation in bulk oil is impacted by chemical factors, such as, prooxidants and antioxidants, and is also related to the existence of physical structures. Bulk oils contain a variety of surface active minor components which are able to form physical structures known as association colloids. These physical structures create oil-water interfaces which seem to be an important site where lipid oxidation occurs in bulk oil. Thus, this research focused on …

Nanoparticle Building Blocks For Functional Structures, Youngdo Jeong

Doctoral Dissertations

A major goal in material science is achieving a desired function using structures fabricated with designed building blocks. Advanced synthetic and self-assembly techniques allow various nanomaterials to become promising building blocks, providing the control of the interaction between building blocks. The unique properties of nanomaterials can be transferred to structured systems. Among nanomaterials, inorganic nanoparticles such as gold nanoparticles (AuNPs), magnetic particles, and quantum dots (QDs) provide useful physical properties stemming from their inorganic core, large surface areas, and oriented surface functionalities. My research has focused on fabricating functional systems using gold nanoparticles (AuNPs), manipulating the interaction between AuNPs, bio-entities, …

Aggressive Signaling In New World Warblers, David Hof

Doctoral Dissertations

In many animal species, communication can enable individuals to resolve conflict without the high potential costs involved in direct fighting. During contests, animals may exchange information about their aggressive motivational state. A central question throughout the study of animal communication research has been whether animal signals convey reliable information, and this question has been particularly relevant to communication during conflicts where the evolutionary interests of competitors directly oppose. Deceptive signaling of aggressive motivation would be highly favored by natural selection because it could allow individuals to gain access to resources they might not gain through direct combat. However, selection should …

Factor Inhibiting Hif's (Fih) Structure Controls O2 Activation And Reactivity, John A. Hangasky Iii

Doctoral Dissertations

Factor Inhibiting HIF (FIH) is a Fe(II)-αKG dependent oxygenase that acts as a cellular oxygen sensor in humans. FIH regulates the transcriptional activity of the hypoxia-inducible factor-1 (HIF-1a or HIF), a transcription factor responsible cellular O₂ homeostasis. Hydroxylation of the target residue HIF-Asn⁸⁰³, found in the C-terminal transactivation domain (CTAD), inactivates HIF-dependent gene expression. Central to FIH’s function is the activation of O₂ after CTAD binding. The mechanistic and structural features of FIH leading to tight coupling between CTAD binding and subsequent O₂-activation and reactivity are key for efficient O₂ sensing. Our mechanistic …

Understanding The Transcriptional Regulation Of Secondary Cell Wall Biosynthesis In The Model Grass Brachypodium Distachyon, Pubudu Handakumbura

Doctoral Dissertations

Secondary cell wall synthesis occurs in specialized cell types following completion of cell enlargement. By virtue of mechanical strength provided by a wall thickened with cellulose, hemicelluloses, and lignin, these cells can function as water-conducting vessels and provide structural support. Several transcription factor families regulate genes encoding wall synthesis enzymes. Certain NAC and MYB proteins directly bind upstream of structural genes and other transcription factors. The most detailed model of this regulatory network is established predominantly for a eudicot, Arabidopsis thaliana. In grasses, both the patterning and the composition of secondary cell walls are distinct from that of eudicots. …

Integrated Modeling Of Land Use And Climate Change Impacts On Multiscale Ecosystems Of Central African Watersheds, Simon Nampindo

Doctoral Dissertations

Assessment and management of ecosystem services demands diverse knowledge of the system components. Land use change occurring mainly through deforestation, expansion of agriculture and unregulated extraction of natural resources are the greatest challenges of the Congo basin and yet is central to supporting over 100 million people. This study undertook to implement an integrated modeling of multiscale ecosystems of central African watersheds and model the impact of anthropogenic factors on elephant population in Greater Virunga landscape. The study was conducted at varied scales, regional, landscape, and community. Regional study included watershed analysis and hydrological assessment using remotely sensed data implemented …