Life Sciences Commons^™

Whey Proteins Cross-Linked By Transglutaminase Or Glycated With Maltodextrin: Physicochemical Bases Of The Improved Heat Stability, Wan Wang

Doctoral Dissertations

Whey protein, as a byproduct in cheese manufacturing, is an ideal source for producing ready-to-drink protein beverages for different market demands, attributed to its high content of essential amino acids and versatile functionalities, bland flavor and good digestibility. Whey protein is a mixture of proteins, which can be categorized into whey protein concentrate (WPC) with a protein content of 50~80% and whey protein isolate (WPI) with a protein content higher than 90%, depending on different separation techniques. Thermal processing is required to ensure microbiological safety and quality of dairy products, leading to denaturation of whey proteins, especially at pH around …

Design And Development Of Seed Hydration Analyzing Device And Its Utilization In Studying Cereal And Legume Hydration, Vinay Kumar Mannam

Doctoral Dissertations

Cereals and legumes are important sources of vegetable-based human nutrition. Together they account for 48.6 % of protein and 8.7 % carbohydrate consumption around the world. During preparation, majority of these agricultural staples are re-hydrated to aid in their digestibility, palatability and the bio-availability of the nutrients.

Study of hydration kinetics of cereals and legumes is an important and valuable necessity for industry and academia to understand and gain insights into seed hydration characteristics. An automatic seed hydration analyzing system is developed as a solution for lack of instruments with broad capabilities to study variety of seed properties. The device …

Wood Decomposition In A Warmer World, Emily Elizabeth Austin

Doctoral Dissertations

Climatic warming is altering species distributions and ecosystem functions across the globe. Wood is an important carbon pool and the fungal communities in wood are relatively simple compared to those in soil. These factors make decomposing wood an ideal system for exploring the influence of decomposer community on the response of decomposition to warming. My research has focused on the effects of warming wood decomposition rates and wood decomposing communities. Using field and lab- based manipulative experiments and field observations I explore the influence of tree species, wood decomposition stage, geography and warming on fungal community structure and activity. In …

From Loop To Strand: Characterization Of The Conformation And Dynamics Of The Human Plasminogen Activator Inhibitor-1 Reactive Center, Tihami Qureshi

Doctoral Dissertations

Plasminogen activator inhibitor-1 (PAI-1), with its cofactor vitronectin (VN), controls the rate of plasmin-mediated fibrin breakdown in blood clots by inhibiting tissue-plasminogen activator (tPA) and urokinase-plasminogen activator (uPA). The activity of PAI-1 is attributed to its reactive center loop (RCL), which is solvent-exposed in an active conformation, but inserts as an additional strand into its central β [beta]-sheet during transition to a latent state and during inhibition. VN slows the latency transition, and the rate at which PAI-1 inhibits the plasminogen activators (PAs) also differs. However, the steps during the latency transition, mechanism of VN stabilization, and basis for inhibitory …

"Every Day, We Have The Opportunity To Make A Difference": Ncaa Division I Female Head Coaches' Experiences Of Care, Susannah Kaye Knust

Doctoral Dissertations

According to sport psychology literature, care is an important part of the coach-athlete relationship (e.g., Jowett & Poczwardowski, 2007; LaVoi, 2004; Poczwardowski, 1997; Wylleman, 2000). However, a systematic study of “exemplar” caring coaches is lacking. Therefore, the purpose of this study was to interview 12 National Collegiate Athletic Association (NCAA) Division I head female coaches of female teams who were identified by others as “exemplar” carers. A semi-structured interview guide was developed using a modified version of Gilligan and colleagues’ (1989) Listening Guide. An adaptation of Hatch’s (2002) political analysis was used to identify major themes found in the transcribed …

Development And Integration Of Informatic Tools For Qualitative And Quantitative Characterization Of Proteomic Datasets Generated By Tandem Mass Spectrometry, Rachel Michelle Adams

Doctoral Dissertations

Shotgun proteomic experiments provide qualitative and quantitative analytical information from biological samples ranging in complexity from simple bacterial isolates to higher eukaryotes such as plants and humans and even to communities of microbial organisms. Improvements to instrument performance, sample preparation, and informatic tools are increasing the scope and volume of data that can be analyzed by mass spectrometry (MS). To accommodate for these advances, it is becoming increasingly essential to choose and/or create tools that can not only scale well but also those that make more informed decisions using additional features within the data. Incorporating novel and existing tools into …

Genetic And Ecological Characterization Of Indigoidine Production By Phaeobacter Sp. Strain Y4i, William Nathan Cude

Doctoral Dissertations

The Roseobacter clade is a widely distributed, abundant, and biogeochemically active lineage of marine alpha-proteobacteria. Members of the Roseobacter lineage are prolific surface colonizers in marine coastal environments, and antimicrobial secondary metabolite production has been hypothesized to provide a competitive advantage in colonization. In this work, Phaeobacter sp. strain Y4I was found to produce the water soluble, blue pigment indigoidine via a nonribosomal peptide synthase-based biosynthetic pathway encoded by a novel series of genetically linked genes, termed igiBCDFE. Comparison of wildtype, non-pigmented, and hyper-pigmented Y4I insertional mutants demonstrated a perfect correlation between indigoidine production and the inhibition of Vibrio …

Ecology And Physiology Of Aerobic Aromatic Catabolism In Roseobacters, Christopher Adam Gulvik

Doctoral Dissertations

Roseobacters are an abundant and trophically versatile lineage of marine bacteria that are especially dominant in coastal salt marshes. Central to understanding of how members of the Roseobacter clade contribute to biogeochemical cycling in the world’s oceans is how these bacteria physiologically respond to mixtures of usable growth substrates present in their environmental niches. A prior study provided evidence that bacterioplankton transcripts most closely related to the Roseobacter Sagitulla stellata E-37 are among the most abundant in coastal systems for biogeochemically significant processes of N, P, and S cycling. Thus, this strain was used throughout this dissertation as an environmentally …

Hybridization As A Stimulus For Adaptation To A Novel Environment, Dylan Robert Dittrich-Reed

Doctoral Dissertations

Understanding processes contributing to the origin of novelty, including ecological transitions in resource or habitat use, is fundamental to evolutionary biology. Early geneticists speculated about the sudden appearance of new species via special macromutations, epitomized by Goldschmidt’s infamous “hopeful monster”. Transgressive segregation during hybridization is a more plausible mechanism for producing “monstrous” phenotypes beyond the range of parental populations. Transgressive hybrid phenotypes can be products of epistatic interactions or additive effects of multiple recombined loci. However, the importance of hybridization in the origin of novelty is contested because we do not know how often hybridization enhances the probability of an …

Exploration Of Breastfeeding Concepts Among Current And Future Parents: Results Of Questionnaires Administered To Chinese And Us University Students And To New Mothers In China, Zixin Lou

Doctoral Dissertations

The objectives were to explore breastfeeding knowledge, attitudes, and intention of future parents, and to investigate indicators and causes of perceived insufficient milk (PIM) supply among Chinese mothers. Objectives were accomplished using a cross-sectional study design. Two questionnaires were developed, one targeting Chinese and US undergraduates, and a second targeting Chinese mothers. In total, 597 undergraduates (395 Chinese; 202 US) and 392 Chinese mothers participated in the study. Data cleaning resulted in a final sample size of 572 for undergraduates (383 Chinese; 189 US) and 341 for Chinese mothers. Results showed that undergraduates in both countries possessed some breastfeeding knowledge …

Toward Direct Biosynthesis Of Drop-In Ready Biofuels In Plants: Rapid Screening And Functional Genomic Characterization Of Plant-Derived Advanced Biofuels And Implications For Coproduction In Lignocellulosic Feedstocks, Blake Lee Joyce

Doctoral Dissertations

Advanced biofuels that are “drop-in” ready, completely fungible with petroleum fuels, and require minimal infrastructure to process a finished fuel could provide transportation fuels in rural or developing areas. Five oils extracted from Pittosporum resiniferum, Copaifera reticulata, and surrogate oils for Cymbopogon flexuosus, C. martinii, and Dictamnus albus in B20 blends were sent for ASTM International biodiesel testing and run in homogenous charge combustion ignition engines to determine combustion properties and emissions. All oils tested lowered cloud point. Oils derived from Copaifera reticulata also lowered indicated specific fuel consumption and had emissions similar to the ultra-low sulfur diesel control. Characterization …

Genetic Analysis Of Bacterial Gene Variations In Sulfidic Springs And The Influence On Geochemistry, Brendan Joseph Headd

Doctoral Dissertations

Culture-independent methods have revolutionized environmental microbiology and geomicrobiology studies and next-generation sequencing and metagenomics techniques continue to reveal the vast genetic diversity of microorganisms. But, these approaches provide comparatively little quantitative information about the roles that naturally occurring microbial gene variations play in local biogeochemical cycling. The goal of this study was to identify how the physical distribution and genetic diversity of microbial genes within a habitat impact environmental geochemistry by examining the biogeography of 16S rRNA genes and bacterial sulfur oxidation (Sox) genes in terrestrial sulfidic springs. 16S rRNA gene pyrosequences were obtained from microbial mats inhabiting eight sulfidic …

Chromatin Insulators: Master Regulators Of The Eukaryotic Genome, Todd Andrew Schoborg

Doctoral Dissertations

Proper organization of the chromatin fiber within the three dimensional space of the eukaryotic nucleus relies on a number of DNA elements and their interacting proteins whose structural and functional consequences exert significant influence on genome behavior. Chromatin insulators are one such example, where it is thought that these elements assist in the formation of higher order chromatin loop structures by mediating long-range contacts between distant sites scattered throughout the genome. Such looping serves a dual role, helping to satisfy both the physical constraints needed to package the linear DNA polymer within the small volume of the nucleus while simultaneously …

Functional Analysis Of Corazonin And Its Receptor In Drosophila Melanogaster, Kai Sha

Doctoral Dissertations

Corazonin (Crz) is an amidated undecapeptide originally isolated from the American cockroach. It has been shown to affect diverse physiological functions in a species-specific manner. However, the functionality of Crz in Drosophila melanogaster has not yet been determined. To gain insight into the role of Crz signaling in vivo, Crz and CrzR null alleles were obtained by transposable element mobilization. Flies carrying a deficiency uncovering Crz and pr-set7 loci were generated via P-element excision, and the latter was rescued by wild-type pr-set7 transgene. A mutation of Crz receptor (CrzR) was generated by Minos-element mobilization from …

The N-Terminus Of The Saccharomyces Cerevisiae G Protein-Coupled Receptor Ste2p: Formation Of Dimer Interfaces And Negative Regulation, Mohammad Seraj Uddin

Doctoral Dissertations

G protein-coupled receptors (GPCRs), the largest family of membrane proteins on the cell surface, play essential roles in signal transduction in all eukaryotic organisms. These proteins are responsible for sensing and detecting a wide range of extracellular stimuli and translating them to intracellular responses. This signaling requires a tight control for receptor activation without which abnormal signal leads to diseases. In fact, malfunctions of these receptors are associated with numerous pathological conditions and currently an estimated 40-50% of therapeutic drugs are designed to target these receptors suggesting that further increases in understanding of GPCRs and the signaling pathways they initiate …

Mechanisms Contributing To The Emergence Of Ranavirus In Ectothermic Vertebrate Communities, Roberto M. Brenes

Doctoral Dissertations

Ranaviruses have been linked to amphibian die-off events in ectothermic vertebrates worldwide. Differences in susceptibility and capacity of transmission among and within classes are poorly understood. My goal was to determine possible mechanisms influencing susceptibility to ranavirus infection in amphibian species and other aquatic vertebrate taxa, as well as the capacity of transmission between classes and the effects of amphibian community composition on ranavirus transmission. I tested 16 amphibian species from USA, Europe, and the pet trade, expanding an existing database developed by the Center for Wildlife Health to 35 amphibian species from 9 families. I also tested the susceptibility …

Validating Approaches For Studying Microbial Diversity To Characterize Communities From Roots Of Populus Deltoides, Migun Shakya

Doctoral Dissertations

Microbial (archaeal, bacterial, and fungal) communities associated with plant roots are central to its health, survival, and growth. However, a robust understanding of root microbiota and the factors that govern their community structure and dynamics have remained elusive, especially in mature perennial plants from natural settings. Although the advent of Next Generation Sequencing (NGS) technologies have changed the scale of microbial ecological studies by enabling exhaustive characterization of microbial communities, the accuracy of taxonomic and quantitative inferences are affected by multiple experimental and computational steps and lack of knowledge of the true ecological diversity. To test for inaccuracies and biases, …

Evolution Of Acquiescence To Manipulation, Mauricio González-Forero

Doctoral Dissertations

A productive framework to study phenotypic evolution is based on the notion of ``inclusive fitness'', which considers how an individual's phenotype affects the fitness of other individuals. A promising extension of the notion of inclusive fitness is that of the ``extended phenotype'', which considers how an individual's phenotype affects its environment, including the phenotype of other individuals. Affecting another individual's phenotype is sometimes referred to as manipulation (which introduces indirect genetic effects). However, manipulated individuals may evolve resistance to manipulation, possibly reducing or eliminating the manipulated behavior (and the indirect genetic effects). In this dissertation I use mathematical modeling to …

A Mathematical Model And Numerical Method For Thermoelectric Dna Sequencing, Liwei Shi

Doctoral Dissertations

DNA sequencing is the process of determining the precise order of nucleotide bases, adenine, guanine, cytosine, and thymine within a DNA molecule. It includes any method or technology that is used to determine the order of the four bases in a strand of DNA. The advent of rapid DNA sequencing methods has greatly accelerated biological and medical research and discovery. Thermoelectric DNA sequencing is a novel method to sequence DNA by measuring the heat that is released when DNA polymerase inserts a deoxyribonucleoside triphosphate into a growing DNA strand. The thermoelectric device for this project is composed of four parts: …

Mechanisms Of Nutrient Limitation And Nutrient Acquisition In Managed And Unmanaged Forest Ecosystems, Matthew A. Vadeboncoeur

Doctoral Dissertations

Understanding the interactions between global change, human and natural disturbances, and other factors on biogeochemical processes in forests is necessary to ensure the sustainability of forest management. Here I report the results of several investigations into nutrient acquisition processes in the forests of New Hampshire. I begin with a meta-analysis of fertilization studies showing that phosphorus (P) and calcium (Ca) as well as nitrogen (N) may limit primary production in deciduous forests of the region. Because these limiting nutrients are all removed from the ecosystem when trees are harvested, I compared nutrient budgets under a range of harvesting scenarios with …

Application Of Computational Molecular Biophysics To Problems In Bacterial Chemotaxis, Davi Ortega

Doctoral Dissertations

The combination of physics, biology, chemistry, and computer science constitutes the promising field of computational molecular biophysics. This field studies the molecular properties of DNA, protein lipids and biomolecules using computational methods. For this dissertation, I approached four problems involving the chemotaxis pathway, the set of proteins that function as the navigation system of bacteria and lower eukaryotes.

In the first chapter, I used a special-purpose machine for molecular dynamics simulations, Anton, to simulate the signaling domain of the chemoreceptor in different signaling states for a total of 6 microseconds. Among other findings, this study provides enough evidence to propose …

Contribution Of Micrornas And Robo4 Signaling After Herpes Simplex Virus Infection: Role For Regulatory Mechanisms, Sachin Vishvas Mulik

Doctoral Dissertations

Herpes simplex virus (HSV) infection of the eye results in chronic immunopathological response in corneal stroma orchestrated by CD4 T cells. Due to its neurotrophic nature, HSV can also invade brain and leads to deadly encephalitis. HSV infection of the eyes leads to corneal neovascularization (CV), which is an important step in the pathogenesis of herpetic stromal keratitis (HSK), an important cause of human blindness. This study was undertaken to investigate the contribution of miRNAs and Robo4 signaling in HSK. The role of miR-132 and miR-155 was evaluated. In the first chapter, we review literature regarding the contribution of miRNAs …

Characterization Of Uncultured, Human Oral Microbiota Using A Targeted, Single-Cell Genomics Approach, Alisha Gail Campbell

Doctoral Dissertations

Microbial communities associated with the human oral cavity are complex, and many oral microbes have yet to be cultured. These uncultured community members are of interest ecologically and phylogenetically, and a number of uncultured species have been positively correlated with oral diseases such as periodontitis. Thus, an approach was adapted to selectively separate single cells from mixed populations of oral bacteria and obtain genomic information for uncultured community members. A combination of fluorescent labeling, cell sorting with flow cytometry and multiple displacement amplification was used to obtain sufficient genomic material for whole-genome pyrosequencing.

The first targets were from uncultured oral …

Femtosecond Laser Patterned Templates And Imprinted Polymer Structures, Deepak Rajput

Doctoral Dissertations

Femtosecond laser machining is a direct-write lithography technique by which user-defined patterns are efficiently and rapidly generated at the surface or within the bulk of transparent materials. When femtosecond laser machining is performed with tightly focused amplified pulses in single-pulse mode, transparent substrates like fused silica can be surface patterned with high aspect ratio (>10:1) and deep (>10 μm) nanoholes. The main objective behind this dissertation is to develop single-pulse amplified femtosecond laser machining into a novel technique for the production of fused silica templates with user-defined patterns made of high aspect ratio nanoholes. The size of the …

Understanding The Origins Of Product Specificity Of Protein Methyltransferases From Qm/Mm Md And Free Energy Simulations, Yuzhuo Chu

Doctoral Dissertations

Protein lysine methyltransferases (PKMTs) catalyze the methylation of certain lysine residues on histone tails using S-adenosyl-L-methionine (AdoMet) as the methyl donor. Regulation of chromatin structure and gene expression through histone lysine methylation depends on the degree of methylation. Therefore, it is of importance to understand the features of PKMTs that control how many methyl groups would be added to the target lysine (product specificity). In my dissertation, I have applied quantum mechanical/molecular mechanical (QM/MM) molecular dynamics (MD) and free energy simulations to understand the origin of the product specificities of SET8, GLP and their mutants. The relative free energy barriers …

Undergraduate Perception Of Introductory Lecture And Laboratory Biology Instructors At The University Of Tennessee Knoxville, Katharina Denise Kendall

Doctoral Dissertations

Undergraduate students entering the higher education system are often unaware of the diverse teaching and learning community they will encounter, including the different instructor types who will teach their classes. In order to accommodate the growing numbers of enrolled students, the higher education system is increasingly reliant on contingent instructors such as non-tenure track faculty members and graduate teaching assistants (GTAs). This dissertation explores undergraduate student perspective of the different instructor types who teach introductory biology courses, with a focus on the University of Tennessee, Knoxville (UTK). The goal of this work is to provide insight regarding how perceived differences …

Role Of Retinoids In The Regulation Of Hepatic Glucose And Lipid Metabolism, Rui Li

Doctoral Dissertations

The liver plays an important role in controlling glucose and lipid homeostasis. Metabolic abnormalities such as obesity and type 2 diabetes are often associated with profound changes in the expression of genes involved in hepatic glucose and lipid metabolism. Dietary nutrients provide us with macronutrients for energy and micronutrients for maintenance of general health. However, the effects of individual micronutrients on the development of metabolic diseases are unknown. Sterol regulatory element binding protein-1c (SREBP-1c) is the master regulator of fatty acid synthesis, and glucokinase (GK) is the key enzyme in glucose metabolism. Based on the preliminary results from our laboratory …

Ant Community Dynamics And The Effects Of Global Warming, Katharine Lisa Stuble

Doctoral Dissertations

This dissertation seeks to provide an understanding of how species coexist and, further, how climate change may alter communities by acting on the mechanisms that promote coexistence. Specifically, I examined coexistence among ant species in eastern deciduous forests and the effects that warming may have on foraging activity. Through a series of field observations, I sought evidence for the importance of four of the most commonly cited mechanisms for coexistence among ant species: the dominance – discovery tradeoff, the dominance – thermal tolerance tradeoff, spatial segregation, and niche partitioning. In this system, I did not find evidence for any of …

A Pilot Study Of The Efficacy And Program Cost-Effectiveness Of Prevention Plus For Childhood Obesity, Shannon Marie Looney

Doctoral Dissertations

Background: In 2007 an Expert Committee published recommendations using a staged approach for the treatment of childhood obesity in the primary care setting. Limited research has evaluated the efficacy of these recommendations. Thus, the primary aim of this study was to test the efficacy of Prevention Plus for the treatment of childhood overweight and obesity in a primary care setting. Cost is a major barrier to translation of research into practice thus, program cost-effectiveness was also evaluated. Methods: Twenty-two children (8.0 ± [plus-minus] 1.8 years; 2.34 ± 0.48 z-BMI; 68.2% female, 72.7% White, 90.9% non-Hispanic) were randomized to one of …

Quorum Sensing And Metabolism In Marine Environments, Amanda May

Doctoral Dissertations

Quorum sensing (QS) is a phenomenon that allows bacteria to communicate with each other. Small molecules known as autoinducers are synthesized and released by bacteria, and once enough members of the community are around to ensure survival, i.e. quorum, a phenotype, e.g. bioluminescence, is expressed. There are two types of QS molecules, intra- and inter-species.

S-4,5-Dihydroxy-2,3-pentanedione (DPD) is a byproduct of the activated methyl cycle which recycles methionine. This has led to the discussion as to whether DPD is a metabolic byproduct or is the interspecies signal as proposed previously. The detection and quantitation of DPD however, has not …