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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 …

Localization Of Chemoreceptors In Azospirillum Brasilense., Anastasia Aksenova

Masters Theses

In order to ensure their survival, bacteria must sense and adapt to a variety of environmental signals. Motile bacteria are able to orient their movement in a chemical gradient by chemotaxis. During chemotaxis, environmental signals are detected by chemotaxis receptors and are propagated via a signal transduction cascade to affect bacterial motility. In a model organism Escherichia coli, chemotaxis receptors, also called MCPs (for methyl-accepting chemotaxis proteins) sense changes in concentration gradients by making temporal comparisons about the chemical composition of their surroundings. Decreased attractant concentration or increased repellant concentration results in conformational changes in the MCPs that culminate …

Plant Functional Traits Mediate Above- And Belowground Species Interactions In Ecological Communities, Courtney E. Gorman

Masters Theses

Functional plant traits provide a means whereby species identity can influence above- and belowground community interactions. To examine the role of plant functional traits in shaping ecological communities, Chapter 1 examines how the evolution of functional differences between closely related groups of endemic and non-endemic species influence associated species interactions, and Chapter 2 examines how plant functional traits can influence associated community composition.

Drd2 And Xkr4: A Genetic Approach To Fescue Toxicosis., Kristine Marie Ely

Masters Theses

Tall fescue (Lolium arundinaceum Schreb) is the most prevalent forage in the Mid-south United States due to its observed hearty nature and ability to withstand heavy grazing. This is due to a symbiotic relationship with an endophytic fungus (Neotyphodium coenophialum). This fungus produces ergot alkaloids, which can bind to many adrenergic, serotonergic, and dopaminergic receptors. One of the primary functions of dopamine is to inhibit prolactin response. Decreased growth, reproduction, lactation, and depressed serum prolactin concentrations are commonly observed in beef cattle grazing endophyte-infected tall fescue. These symptoms are collectively referred to as fescue toxicosis, and …

Evaluation Of The Over-Expression Of A Miscanthus X Giganteus Ppdk (C4ppdk1) In Switchgrass (Panicum Virgatum) For Improved Cold Temperature C4 Photosynthesis, Mathew Christian Halter

Masters Theses

Switchgrass (Panicum virgatum) has been proposed as a potential biofuel feedstock to aid in the displacement of petroleum-based combustible fuels over the course of the next several decades. Improving the yield potential of this perennial grass is therefore of economic interest. Increased net ethanol yields can be achieved in cellulosic feedstocks via two means: 1. Improved sugar release from digestible cell wall materials, 2. Increased overall biomass yield. The latter is the subject of this study.

As a C4 photosynthetic plant, switchgrass is highly productive in the hot, humid climate of the southeastern United States. By bypassing the …

Performance Of Beef Cattle Grazing Native Warm-Season Grasses In An Integrated Forage/Biofuels System In The Mid-South, William Matthew Backus

Masters Theses

Early season (ES) and full season (FS) grazing strategies were used to evaluate performance of stocker steers grazing native warm-season grasses (NWSG) in 2010, 2011 and 2012 in two experiments. Experiment one was conducted at the Research and Education Center (REC) at Ames Plantation near Grand Junction and experiment two was conducted at Highland Rim REC near Springfield in which Angus and Angus cross steers (268±25kg) were used in completely randomized design with three forage treatments: 1) switchgrass (Panicum virgatum L.); 2) a combination of big bluestem (Andropogon gerardii Vitman) and indiangrass (Sorghastrum nutans); and 3) …

The Seasonality Of Two Parasitoids (Spathius Agrili And Tetrastichus Planipennisi) Of The Emerald Ash Borer, Agrilus Planipennis, And A Survey For Native Natural Enemies Of The Emerald Ash Borer In Eastern Tennessee, Nicholas Andrew Hooie

Masters Theses

The emerald ash borer (EAB), Agrilus planipennisi Fairmaire (Coleoptera: Buprestidae), is an invasive species of bark borer native to eastern Asia whose primary habitat and food sources are trees in the genus Fraxinus. EAB is a major pest of all North American Fraxinus species and is responsible for mortality of millions of trees across its current North American range of 23 U.S states and 2 Canadian providences. After the discovery of EAB in Tennessee in 2010, parasitoid releases were started under the national EAB Biological Control Program. A research project was initiated in 2012 to 1) study the seasonality …

Impact Of Heat Stress On Germinal Vesicle Breakdown And Lipolytic Changes During In Vitro Maturation Of Bovine Oocytes, Leah Marie Hooper

Masters Theses

The main objective of this research was to examine the lipolytic changes in triglyceride and phospholipid as well as the incidence of germinal vesicle breakdown during IVM of heat-stressed oocytes compared to non-stressed oocytes. To this end, cumulus-oocyte complexes were matured for 0, 2, 4, 6 or 24 hIVM at 38.5 or 41.0°C (first 12 h only, then transferred to 38.5°C). Triglyceride and phospholipid levels decreased by 2 hIVM (P = 0.0009 and P = 0.0005, respectively) but remained fairly constant to 24 hIVM; lipid decline was not affected by maturation temperature. Elevated maturation temperature hastened meiotic progression by 4 …

Relationships Of Temperament, Endocrine, Reproductive, And Behavioral Parameters Measured During Performance Testing Of Bulls, Sierra Ashley Lockwood

Masters Theses

The aim of this study was to examine relationships between bull temperament, behavior, growth, endocrine, and reproductive parameters measured over an 84 d test period. Bulls (n = 65) were reared in 6 pens separated on BW and age. Pen scores were assigned on d -1, 27, 55 and 83. On d 0, 28, 56, and 84, exit velocity, BW, time it took each bull to leave the chute, bull order through chute, and hair and blood samples were recorded or collected. Frame score was calculated, carcass ultrasounds and breeding soundness exams were performed on d 84. ADG was calculated …

Tillage, Cover Crop And Nitrogen Fertilization Effects On Soil Microbial Carbon Dynamics Under Long-Term Cotton Production, Molefi Jacob Mpheshea

Masters Theses

Effective soil management requires a deeper understanding of how internal soil carbon (C) works. This is vital as cycling is tightly linked with nutrient cycling processes. This study evaluated the effect of agronomic practices including tillage (no-till and tilled), cover crops (no cover, hairy vetch - Vicia villosa L, and winter wheat - Triticum aestivum. L ) and different N fertilizer rates ( 0, 34 and 101 kg N per hectare ) on soil microbial C dynamics as measured by soil microbial biomass C (SMBC) along with soil microbial respiration over the 2013 cotton growing season at Jackson, West …

Diversity And Function Of Sulfur Cycling Microorganisms In Sediments From Subglacial Lake Whillans, Antarctica, Alicia Marie Purcell

Masters Theses

There is a growing consensus that metabolically and phylogenetically diverse assemblages of microorganisms mediate subglacial nutrient and elemental cycling. Subglacial Lake Whillans (SLW), located under 801 m of glacial ice, was recently penetrated using environmentally clean protocols. SLW is a permanently dark, cold (-0.5 °C [degrees Celsius]), and shallow (~2.2 m) freshwater lake beneath the West Antarctic Ice Sheet. The presence and diversity of key functional genes involved in dissimilatory sulfur oxidation and reduction were examined at various depths in two sediment cores taken from SLW. Our data show a diversity of sulfur transformation genes throughout the top 34 cm …

A Step Towards Understanding Of The Molecular Basis Of Ligand Promiscuity In The Aminoglycoside Modifying Enzymes, Sherin R. Raval

Masters Theses

Aminoglycosides have proven very useful in the treatment of infections; lately their effectiveness has been greatly reduced due to increasing resistance. Among many known mechanisms of resistance to aminoglycosides, enzymatic modification is the most prevailing. More than 14 aminoglycoside -N3-acetyltransferases- a class of aminoglycoside modifying enzymes, are known today. This study focuses on a pair of acetyl transferases: The aminoglycoside-N3- acetyltransferase IIIb (AAC-IIIb) and the aminoglycoside-N3- acetyltransferase IIa (AAC-IIa). AAC-IIa and AAC-IIIb are very similar in their amino acid sequence and structure – yet they have a strong difference in their substrate selectivity, kinetic …

The Benefits Of Ffa Membership As Part Of The Three-Circle Model In Agricultural Education, Chelsea Brooke Rose

Masters Theses

The purpose of this study was to understand the benefits of membership in the Future Farmers of America (FFA) student leadership organization among Tennessee FFA members by surveying members attending Camp Clements FFA Leadership Training Camp. The study focused on the fulfillment of FFA members’ basic human needs as defined by Abraham Maslow (1943). The three needs on which this study focused are: love and belonging, self-esteem, and self-actualization (1943). The study found that a majority of FFA members’ three basic human needs are met due to their involvement in career development events, leadership positions, and other FFA activities. Of …