Biochemistry, Biophysics, and Structural Biology Commons^™

The Effects Of Molecular Chaperones On Tau Fibril Assembly, Ahmed Omran

Electronic Theses and Dissertations

The accumulation of microtubule-associated protein tau into fibrillar aggregates is the hallmark of Alzheimer’s disease and other neurodegenerative disorders, collectively referred to as tauopathies. Fibrils can propagate from one cell to the next and spread throughout the brain. However, a study shows that only small aggregates can be taken up by cultured neuronal cells. The mechanisms that lead to the breakage of fibrils into smaller fragments remain unknown. In yeast, the AAA+ chaperone HSP104 processes the reactivation of protein aggregates and is responsible for fragmentation of fibrils. This study focused on investigating the effects of molecular chaperones on tau fibrils …

Screening Of Natural Products For Their Effect On Kallikrein-Kinin System: Potential Implications In The Treatment Of Hereditary Angioedema, Hassan Abdu Madkhali

Electronic Theses and Dissertations

Plasma prekallikrein (PK) activation exerts both physiological and pathological effects within the cardiovascular system and central nervous system (CNS). Activated PK (kallikrein) controls cytokine release from human mononuclear cells and controls both the intrinsic blood coagulation and the alternative complement cascades. The uncontrolled activation of these cascades results in the development of pathological pain and angioedema. Increased plasma kallikrein levels are associated with hereditary angioedema (HAE) and myocardial infarction, whereby kallikrein amplifies the generation of activated factor XII (FXIIa) and bradykinin (BK) release from high molecular weight kininogen (HMWK). The primary objective of this study was to screen natural products …

Synthesis And Characterization Of Antimicrobial Non-Color Forming Silica-Silver Nanocomposite, Joshua Bazata

Electronic Theses and Dissertations

Silver has been utilized for its antimicrobial properties for thousands of years in a variety of fields, extending the shelf life of food and water, rendering eating utensils sanitary, and more recently in biomedical applications such as silver based antiseptic creams. While effective as an antimicrobial agent at very low concentrations (µg/mL), silver imparts a strong color to objects it is incorporated into, due to its high plasmonic efficiency. The goal of this study was to determine if incorporating silver nanoparticles into a silica matrix could reduce or eliminate the plasmonic signal, while retaining the antimicrobial effects of the silver …

Evaluation Of Inhibitors Of Histone Deacetylases As Potential Neurotrophic Agents, Surabhi Shukla

Electronic Theses and Dissertations

The inhibitors of histone deacetylases (HDACs) have shown promising neuroprotective and neuroactive properties. A set of pan- and isoform-specific HDAC inhibitors were evaluated for neurotrophic activity on Neuroscreen-1 (NS-1) cells, a subclone of PC-12 (rat pheochromocytoma) cells.

The HDAC inhibitors were tested alone and in combination with nerve growth factor (NGF). An in vitro method has been standardized that measures neurite outgrowth along with cytotoxicity of test compounds in a single assay. The neurotrophin signaling pathways were interrogated with selective inhibitors of MEK1/2 (PD98059/U0126) PI3K (LY294002) and TrkA (GW441756) and phosphorylation of target kinases. Associated factors namely, acetylation of histones …

Evaluation Of Intestinal Microbial Diversity And A New Antibiotic Regimen In Crohn's Disease Patients, Karel Alcedo

Electronic Theses and Dissertations

Crohn's disease (CD) is a chronic granulomatous inflammatory bowel disease involving Mycobacterium avium subspecies paratuberculosis (MAP). Other microorganisms such as adherent-invasive Escherichia coli (AIEC) have also been proposed in CD association. To date, only one study investigated both MAP and AIEC simultaneously using peripheral blood but not in affected intestinal tissues. A standardized and effective antibiotic therapy against MAP and/or AIEC is needed for better treatment. Three antibiotic drugs – Clarithromycin (CLA), Rifabutin (RIF), and Clofazimine (CLO) have been used to treat CD patients suspected with MAP infection. However, the outcome has been controversial. The treatment dosage is high, the …

Genetically-Programmed Suicide Of Adrenergic Cells In The Mouse Leads To Severe Left Ventricular Dysfunction, Impaired Weight Gain, And Symptoms Of Neurological Dysfunction, Aaron Owji

Electronic Theses and Dissertations

Phenylethanolamine-N-methyltransferase (Pnmt) catalyzes the conversion of noradrenaline to adrenaline and is the last enzyme in the catecholamine biosynthetic pathway. Pnmt serves as a marker for adrenergic cells, and lineage-tracing experiments have identified the embryonic heart and hindbrain region as the first sites of Pnmt expression in the mouse. Pnmt expression in the heart occurs before the adrenal glands have formed and prior to sympathetic innervation, suggesting that the heart is the first site of catecholamine production in the mouse. The function of these Pnmt+ cells in heart development remains unclear. In the present study, we test the hypothesis that (i) …

Differential Expression Of Proteins Involved In Vldl Trafficking Causes Reduced Vldl Secretion In Male Ames Dwarf Mice, Faisal Ahmed Moinuddin

Electronic Theses and Dissertations

Cardiovascular diseases (CVDs) have been recorded as the number one cause of death worldwide, accounting for 32% of total deaths annually. More than two-thirds of all CVD cases are associated with atherosclerosis, which is the accumulation of fats and other substances causing plaque formation in the interior walls of major arteries. This leads to narrowing of the lumen and hardening of the arteries, ultimately resulting in angina, heart attack and/or stroke. Studies have shown that the pathogenesis of atherosclerosis and associated CVDs is strongly linked to elevated secretion of liver-specific lipoproteins called very-low-density-lipoprotein (VLDL). VLDLs are crucial lipoproteins responsible for …

Synthesis And Characterization Of Core-Shell Zinc Silica Nanoparticles And Zinc Silica Nanogels For Agricultural Applications., Megan Berroth

Electronic Theses and Dissertations

Plant pathogens are a serious problem facing the agricultural industry today. Current methodologies use copper based biocides as the main form of defense. Unfortunately this can lead to damaging environmental effects and increased rates of antimicrobial resistance. In this study, antimicrobial activity of multiple alternative zinc-based nanoformulations were tested against three important plant pathogens: Xanthomonas alfalfae, Pseudomonas syringae, and Clavobacter michiganensis. Xanthomonas sub species cause Citrus canker, a devastating disease that affects millions of citrus trees worldwide while the latter two affect tomato crops. Materials synthesis was completed and the resulting nanoformulations were characterized by Atomic Absorption Spectroscopy, Scanning Electron …

Fmf Assay For Assessing Vaccine Generated Antibodies In A Biomimetic Manner, Vipra Dhir

Electronic Theses and Dissertations

Traditional functional assays such as hemagglutination inhibition (HAI) and micro-neutralization (MN) assays have been routinely used for assessing the vaccine response, since influenza vaccine has been administered in people (1940). Such assays are not always predictive regarding the protection conferred by the influenza vaccine and are not able to monitor neutralization related to stem region of influenza hemagglutinin responsible for virus membrane fusion in the endosomes. In order to study Influenza vaccine response in a more biomimetic manner and overcome the deficiencies of the traditional functional assays, we developed a fluorescent membrane fusion assay (fMF). The assay uses viruses labeled …

Functional Identification Of Nucleus Tractus Solitarius (Nts) Barosensitive Neurons: Effect Of Chronic Intermittent Hypoxia (Cih), Jenya Kolpakova

Electronic Theses and Dissertations

Chronic Intermittent Hypoxia (CIH) is a model used to study obstructive sleep apnea (OSA). Previously, we showed that baroreflex control of heart rate (HR) (baroreflex sensitivity) is reduced in CIH rats. While afferent function and HR in response to vagal efferent stimulation are enhanced, the effect of CIH on the central components, in particular NTS, is still not completely understood. F344 rats (3-4 mo) were exposed either to CIH or room air (RA) for 35-50 days. Following CIH exposure, rats were anaesthetized with Ket/Ace. Using single-unit extracellular recording technique, we recorded NTS barosensitive neurons in response to arterial pressure (AP) …

A Comparison Of Whole Body Mercury Concentrations Of Mummichogs (Fundulus Heteroclitus) And Atlantic Silversides (Menidia Menidia), Daniel P. Ferons

Electronic Theses and Dissertations

Few studies have focused on mercury cycling within salt marsh estuaries. Mummichogs (Fundulus heteroclitus) and Atlantic silversides (Menidia menidia) are two species of forage fish that live year round in South Carolina salt marshes. During high tide, mummichogs feed from the water column, sediment, and off of smooth cordgrass while Atlantic silversides prey upon zooplankton. In this study, total and methyl mercury within mummichogs and Atlantic silversides from Dunn Sound, SC were quantified and compared over four seasons throughout 2014. Gut contents were also quantified and compared to determine if there was a dietary impact on the concentrations of total …

Characterization Of A Putative Phospholipase D ´ Like Gene As A Lipid Signaling Modulator And Its Role In Salicylic Acid Mediated Defense Pathway In Nicotiana Tabacum, Phillip T. Dean

Electronic Theses and Dissertations

Plants are in a perpetual evolutionary arms race with a wide range of pathogens. Their sessile nature has led plants to evolve defense mechanisms that can quickly recognize a unique stressor and deploy a resistance tailored for a specific attack. The salicylic acid (SA) mediated defense pathway has been shown to be one of the major defense tactics plants can initiate to defend themselves against microbial pathogens. Following a pathogen attack high levels of methyl salicylate (MeSA) are produced that can be converted to SA by the enzyme salicylic acid binding protein 2 (SABP2). A yeast two-hybrid screening was performed …

Regulation Of C-Reactive Protein Gene Expression And Function, Avinash N. Thirumalai

Electronic Theses and Dissertations

Human C-reactive protein (CRP) is the prototypic acute phase protein whose serum concentration increases rapidly during inflammation. CRP is also associated with atherosclerosis; it is deposited at lesion sites where it may interact with modified lipoproteins. There are 2 major questions regarding CRP: 1. How is the serum concentration of CRP regulated? 2. What are the functions of CRP in atherosclerosis?

Our first aim was to determine the role of the constitutively expressed transcription factor Oct-1 in regulating CRP gene expression. We found that Oct-1 overexpression inhibited (IL-6+IL-1β)- induced CRP gene expression; maximal inhibition required the binding of Oct-1 to …

Enzyme Kinetics : 6-Phosphofructo-2-Kinase/2,6-Bisphosphatase., Jennifer Clark

Electronic Theses and Dissertations

Altered energy metabolism is an established hallmark of cancer cells. Fructose-2,6-bisphosphate is an allosteric activator of glycolysis and its concentration in a cell is dictated by the 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatases (PFKFB1-4) family of bifunctional enzymes. The PFKFB family of enzymes are characterized by their different kinase: bisphosphatase activities and were originally determined to be tissue-specific. More recent data however suggest that multiple isoforms are co-expressed in both normal and neoplastic tissues. PFKFB4 is highly expressed in human cancer, strongly induced by hypoxia, and required for the survival of cancer cells. However, it remains unclear whether the kinase or phosphatase activity of human …

The Role Of Stem Cells In Adipose Tissue Remodeling., Candice Reshay Holden 1988-

Electronic Theses and Dissertations

The work presented in this dissertation outlines the role of stem cells in the remodeling of adipose tissue under conditions of nutrient excess. Obesity-induced variations in adipose tissue stem cell distribution were uncovered by analysis of the stromal vascular fraction isolated from mice fed a high fat diet for several weeks. Bone marrow cell transplantation was used to determine the derivation of progenitor cells found in adipose tissue; and supplementation of depleted progenitor cell populations achieved via direct cell transplantation, helped to determine the contribution of these progenitor cells to the remodeling process. The dissertation is presented in five chapters …

Troglitazone Suppresses Glutamine Metabolism And Tumor Cell Growth Through A Ppar-Independent Mechanism., Miriam R. Reynolds 1965-

Electronic Theses and Dissertations

In tumor cells, glutamine metabolism provides anaplerotic carbon for the TCA cycle, fatty acid synthesis, and precursors for the production of nucleotides and glutathione. This metabolic alteration is primarily driven by disruptions in oncogenic or tumor suppressor function and results in glutamine dependency for tumor cell survival. Troglitazone, a PPARγ agonist, has been reported to alter glutamine metabolism. This thesis project addresses whether troglitazone treatment could disrupt glutamine metabolism in glutamine-dependent tumor cells. Results obtained with troglitazone treatment include: dose-dependent inhibition of cell proliferation, glutamine uptake, glutaminolytic protein expression, steady-state ATP levels, and glutamine carbon flux into the TCA cycle. …

A Comprehensive Study Of The Effects Of Neurotoxins On Noradrenergic Phenotypes, Neuronal Responses And Potential Intervention By Antidepressants In Noradrenergic Cells, Yan Wang

Electronic Theses and Dissertations

It has been reported that locus coeruleus (LC) degeneration precedes the degeneration of other neurons in the brain in some neurodegenerative diseases like Alzheimer’s disease (AD) and Parkinson’s disease (PD). However, the precise mechanisms of neurodegeneration remain to be elucidated. N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP4) has been widely used as a noradrenergic neurotoxin in the development of AD and PD animal models for specific LC degeneration. However, the precise mechanism of action of DSP4 remains unclear. An increased systemic DNA damage caused by neurotoxin or oxidative stress has been found to be related to the pathogenic development of neurodegeneration. The process of neurodegeneration …

Analyzing The Interactions Between Xenopus Tropicalis Mc2r, Mc5r, And The Mraps: Modeling The Regulation Of Frog Interrenal Cells, Yesenia Garcia

Electronic Theses and Dissertations

The role of Melanocortin 2 Receptor (MC2R) in adrenal/interrenal glucocorticoid secretion has been well documented in many organisms. Studies in mammals have shown that in the adrenal gland two melanocortin receptors and two melanocortin receptor accessory proteins are expressed: MC2R, MC5R, MRAP, and MRAP2. The MRAPs have an opposite effect on the cell surface expression of MC2R and MC5R. In mammals, MRAP aids MC2R but inhibits MC5R cell surface expression. This thesis aims to explore the functional relationship between MC2R, MC5R, MRAP, and MRAP2 in Xenopus tropicalis to determine if the MRAPs have a similar effect on amphibian MC2R and …

Mitochondrial Involvement In Neuronal Cell Death, Josie J. Gray

Electronic Theses and Dissertations

Neuronal cell death via apoptosis or necrosis underlies several devastating neurodegenerative diseases associated with aging. Mitochondrial dysfunction resulting from oxidative or nitrosative stress often acts as an initiating stimulus for intrinsic apoptosis or necrosis. These events frequently occur in conjunction with imbalances in the mitochondrial fission and fusion equilibrium, although the cause and effect relationships remain elusive. In this thesis, I demonstrate in primary rat cerebellar granule neurons (CGNs) that oxidative or nitrosative stress induces an N-terminal cleavage of optic atrophy-1 (OPA1), a dynamin-like GTPase that regulates mitochondrial fusion and maintenance of cristae architecture. This cleavage event is indistinguishable from …

Biophysical And Computational Investigations Into G-Quadruplex Structural Polymorphism And Interaction With Small Molecules., Huy Tuan Le

Electronic Theses and Dissertations

In the cell, guanine-rich nucleic acids can self-assemble into unique four stranded tertiary structures known as G-quadruplexes. G-quadruplex formation in the telomere leads inhibits telomerase, an enzyme activated in cancer cells to maintain the telomere and allowing for cancer cells to achieve immortality. G-quadruplex formation in the promoters and 5’-untranslated regions regulates the expression of many oncogenes. Furthermore, G-quadruplex formation during cellular replication promotes genomic instability, a characteristic which enables tumor development. Because of their implication in cancer, G-quadruplex structures have emerged as attractive drug targets for anti-tumor therapeutics. In the current dissertation work, we present three experimental approaches to …

Genetic And Mechanistic Analysis Of Rat Mammary Cancer Susceptibility., Jennifer Sanders

Electronic Theses and Dissertations

Breast cancer is a complex disease, which is influenced by genetic, epigenetic and environmental components. Genetic susceptibility to breast cancer is made up of high, moderate and low penetrance alleles. High and moderate penetrance alleles are rare and constitute only a small percentage of the genetic susceptibility. Most variation in genetic susceptibility is controlled by low- penetrance, common polymorphisms. Comparative genetics uses model organisms to study human disease. Rat strains exhibit different susceptibility phenotypes to chemical induced carcinogenesis. The Wistar-Furth (WF) rat strain is susceptible to chemically induced mammary carcinogenesis, while the Wistar-Kyoto (WKy) and Copenhagen (COP) rat strains are …

Mirna-21 Has Anti-Inflammatory Effects In The Macrophage Response To Peritonitis., Rebecca Elise Barnett

Electronic Theses and Dissertations

This project investigated the role of miRNA-21 in the macrophage response to peritonitis; with the goal of understanding whether the associated mechanism has potential benefits in the clinical treatment of peritonitis. A novel therapeutic intervention in the treatment of peritonitis could modulate the host immune response to decrease an exaggerated pro-inflammatory innate response and then prevent or ameliorate the development of sepsis and organ failure. We found the following: 1. MiRNA-21 expression increases in peritoneal macrophages after lipopolysaccharide (LPS) stimulation. 2. Over expression of miRNA-21 decreases TNF-a secretion from macrophages after LPS stimulation. Suppression of miRNA-21 expression results in increased …

Characterization Of A Putative Sir2 Like Deacetylase And Its Role In Sabp2 Dependent Salicylic Acid Mediated Pathways In Plant, Md I. Haq

Electronic Theses and Dissertations

Salicylic Acid Binding Protein2 (SABP2) is an enzyme known to play important role in SA mediated pathway. SBIP-428 (SABP2 Interacting Protein-428), a SIR2 like deacetylase, has been found to interact with SABP2. We demonstrate that SBIP-428 functions as a Sirtuin deacetylase. We show that SBIP-428 itself is lysine acetylated. Interactions of a SBIP-428 with SABP2 also raised the possibility of SABP2 itself being lysine acetylated. The recombinant purified SABP2 or native partially purified SABP2 displayed no acetylation. In response to TMV infection, the expression of SBIP-428 was down regulated at 48 hpi. In addition, SBIP-428 was up regulated in plant …

Biophysical Characterization Of The Votu Proteases From The Cchf And Dugbe Nairoviruses, Glenn C. Capodagli

Electronic Theses and Dissertations

My research focuses on understanding the substrate specificity of the viral homolog of the ovarian tumor domain protease superfamily (vOTU) from nairoviruses, and the structural reasons for their specificities. The vOTU from the Crimean-Congo Hemorrhagic Fever Virus (CCHFV) has been implicated in the down-regulation of the innate immune response through its ability to cleave post-translational modifications via Ubiquitin (Ub) as well as the Ub-like interferon-stimulated gene 15 (ISG15). vOTU homologs have been found in numerous viruses across several families. Moreover, the effects of these viruses range in severity from mild flu-like symptoms to mortality depending on the species of the …

The Anti-Obesogenic Effects Of Nitric Oxide., Brian Edward Sansbury 1985-

Electronic Theses and Dissertations

Obesity is a strong risk factor for developing type 2 diabetes and cardiovascular disease and has quickly reached epidemic proportions with few tangible and safe treatment options. While it is generally accepted that the primary cause of obesity is energy imbalance, i.e., more calories are consumed than are utilized, understanding how caloric balance is regulated has proven a challenge. Molecular processes and pathways that directly regulate energy metabolism represent promising targets for therapy. In particular, nitric oxide (NO) is emerging as a central regulator of energy metabolism and body composition. NO bioavailability is decreased in animal models of obesity and …

Mechanisms Of Action And Co-Optive Evolution For Hypervariable Courtship Pheromones In Plethodontid Salamanders., Wilburn Beau Wilburn

Electronic Theses and Dissertations

Pheromones are an important type of chemical cue used by most animals to convey information between individuals. For more than 100 million years, male plethodontid salamanders have utilized a system of non-volatile, proteinaceous pheromones to regulate female mating behavior and receptivity. One of these pheromone components, Plethodontid Modulating Factor (PMF), is a hypervariable protein related to the three-finger protein (TFP) superfamily. Previous studies revealed that PMF persists as a rapidly evolving multi-isoform mixture. However, many characteristics of PMF as a pheromone remained undetermined, including gene structure and transcriptional regulation, translational regulation, protein structure, evolutionary mechanisms, and the isoform effects on …

Inflammation-Resolving Lipid Mediators Promote Revascularization To Enhance Wound Healing., Michael Jingyuan Zhang

Electronic Theses and Dissertations

Wound healing is a highly concerted cellular process that begins with inflammation and proceeds to resolution to revascularize the site of injury. Although inflammation is essential to revascularization during wound healing, it is now recognized that resolution is an active process that is equally important. Other investigations have implicated a beneficial effect of resolving inflammation and promoting resolution in the remission of inflammatory pathologies. Recently investigations have yielded a novel class of ?-3 fatty acid derived lipid mediators, biosynthesized by leukocytes, which are capable of resolving inflammation and promoting resolution. We therefore hypothesized that these leukocyte-derived pro-resolving lipid mediators can …

Epigenetic Modifications Associated With Aortic Remodeling In Hyperhomocysteinemia., Nithya Narayanan

Electronic Theses and Dissertations

Background: Hyperhomocysteinemia (HHcy) is prevalent in hypertensive patients and is an independent risk factor for aortic pathologies. HHcy is known to cause an imbalance between matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) leading to accumulation of collagen in the aorta resulting in stiffness and development of hypertension. Although the exact mechanism of extracellular matrix remodeling (ECM) is unclear, emerging evidence implicates epigenetic regulation involving DNA methylation. The purpose of the study was to investigate whether inhibition of DNA methylation reduces high blood pressure by regulating aortic ECM remodeling in HHcy. Methods: In the first set of experiments, we …

Myocyte-Specific Overexpression Of Stromal Cell-Derived Factor 1 Facilitates Cardiac Regeneration And Improves Myocardial Function After Infarction In Mice., Detlef Ernst-Rudolf Obal

Electronic Theses and Dissertations

Background: Interruption of cardiac stromal cell-derived factor 1 (SDF1)-CXCR4 axis by chronic AMD3100 administration increased myocardial injury after permanent coronary artery ligation, demonstrating the important role of this chemokine in cardiac regeneration. Hypothesis: Cardiomyocyte-specific conditional overexpression of SDF prevents heart failure after permanent coronary ligation and facilitates cardiac regeneration. Methods and Results: Tetracycline-controlled, a-myosine heavy chain promoter directed overexpression of cardiac SDF resulted in a significant increase of SDF expression (SDF: 8.1 ng / g protein) compared with littermate WT mice (0.02 ng / g protein) four weeks after doxycycline withdrawal. SDF overexpression increased AKT and casein kinase 1 levels …

Augmentation Of Ras-Induced Cell Transformation : A New Role For Mir-200a In Malignancy., Lindsey Erin Becker

Electronic Theses and Dissertations

Cancer is a multistep disease that begins with malignant cell transformation and frequently culminates in metastasis and death. MicroRNAs (miRNAs) are small regulatory 21-25-nt RNA molecules and are frequently deregulated in cancer. The majority of miRNAs are estimated to be co-expressed with neighboring miRNAs as clusters. Many miRNA clusters coordinately regulate multiple members of cellular signaling pathways or protein interaction networks. miR-200a is a member of the miR-200 family, which are known to be strong inhibitors of the epithelial to mesenchymal transition. As such, the tumor suppressive role of miR-200a in oncogenesis has been well studied; however, recent studies have …