Molecular Biology Commons^™

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 …

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 …

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 …

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 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 …

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 …

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 …

Validation Of A Novel Hypothesis Of Generating Foam Cells By Its Use To Study Reverse Cholesterol Transport, Bhaswati Sengupta

Electronic Theses and Dissertations

Generation of foam cells, an essential step for reverse cholesterol transport (RCT) studies, uses the technique of receptor dependent macrophage loading with radiolabeled acetylated Low Density Lipoprotein (Ac-LDL). In this study, we used the ability of a biologically relevant detergent molecule, Lysophosphatidylcholine (Lyso PtdCho), to form mixed micelles with cholesterol or cholesteryl ester (CE) to generate macrophage foam cells. Fluorescent or radiolabelled cholesterol / Lyso PtdCho mixed micelles were prepared and incubated with RAW 264.7 or mouse peritoneal macrophages. Results showed that such micelles were quite stable at 4°C and retained the solubilized cholesterol during one month storage. Macrophages incubated …

In Vitro Characterization Of Unmodified And Pyroglutamylated Alzheimer's Amyloid Beta Peptide, Jason Matos

Electronic Theses and Dissertations

Plaques of amyloid β peptide (Aβ) are a hallmark trait of Alzheimer’s disease (AD). However, the precise role of Aβ aggregates is not well understood. Recent studies have identified that naturally occurring N-terminal truncation and pyroglutamylation of Aβ significantly increases its neurotoxicity by an unknown mechanism. Content of pyroglutamylated Aβ (pE-Aβ) in AD brains has been shown to reach up to 50% of total Aβ. Modified pE-Aβ co-aggregates with Aβ by a seeding mechanism and forms structurally distinct and highly toxic oligomers. We studied structural transitions of the full-length Aβ1-42, its pyroglutamylated form AβpE3-42, their 9:1 (Aβ1-42/AβpE3-42) and 1:1 molar …

Purification And Characterization Of A Novel Selenocysteine Lyase From Enterococcus Faecalis, Samantha Nelson

Electronic Theses and Dissertations

A previous study identified Enterococcus faecalis as one of two bacteria known to have the selD gene and other selenium related genes without having the genes necessary to make selenocysteine or selenouridine. EF2570, a gene in the cluster, was later shown to be upregulated during biofilm formation and also responsible for a selenite- and molybdate-dependent increase in biofilm formation in vitro. The protein encoded was identified as a selenium dependent molybdenum hydroxylase (SDMH), enzymes that contain a labile selenium atom required for activity. While the process of inserting selenocysteine into a protein is well known, the process by which a …

Establishment Of Methods For Isolation Of Pnmt+ Cardiac Progenitor Cells, Namita Varudkar

Electronic Theses and Dissertations

Cardiovascular disease is the leading cause of death in the United States. Millions of patients suffer each year from endothelial dysfunction and/or debilitating myocardial damage resulting in decreased quality of life and increased risk of death or disablement. Current pharmacological approaches are only partly effective at treating cardiovascular disease, and hence, better strategies are needed to provide significant improvements in treatment options. Cardiac stem/progenitor cells have the potential to regenerate myocardial tissue and repair damaged heart muscle. There are many different types of cardiac progenitor cells, and each may have certain unique properties and characteristics that would likely be useful …

Antimicrobial Peptide Resistance And Immunomodulation By Hiv-1 Gp41, Matthew Wood

Electronic Theses and Dissertations

Fusion inhibitors are a class of antiretroviral drugs used to prevent entry of HIV into host cells. Many of the fusion inhibitors being developed, including the drug enfuvirtide (ENF), are peptides designed to mimic, and thereby competitively inhibit, the viral fusion protein gp41. An exception to this is a class of cyclic, cationic, antimicrobial peptides known as θ-defensins, which are produced by many non-human primates and exhibit broad-spectrum antiviral and antibacterial activity. Currently, the θ-defensin analog RC-101 is being developed as a microbicide to prevent sexual transmission of HIV-1. Understanding potential RC-101 resistance, and how resistance to other fusion inhibitors …

Genetic And Biochemical Characterization Of The Roles Of Two Putative Purine Transporters In The Infectious Cycle Of Borrelia Burgdorferi, Sunny Jain

Electronic Theses and Dissertations

Lyme disease, the most common tick borne disease in United States, is caused by the bacterial pathogen Borrelia burgdorferi. In nature, B. burgdorferi exists in an enzootic infectious cycle between an arthropod vector and mammalian hosts. Identification and characterization of the genes essential for B. burgdorferi survival throughout its infectious cycle is an important step toward understanding the molecular mechanisms involved in B. burgdorferi pathogenesis. B. burgdorferi contains a small genome, which lacks the genes encoding for the enzymes required for de novo synthesis of amino acids, fatty acids and nucleic acid precursors. Therefore, the spirochete is dependent upon the …

Role Of Cardiac Catecholamines In Embryos And Adults Under Stress, Candice Baker

Electronic Theses and Dissertations

Cardiovascular disease is responsible for the loss of one life every 38 seconds and accounts for 26.6 percent of all infants that die of congenital birth defects. Adrenergic hormones are critically important regulators of cardiovascular physiology in embryos and adults. They are key mediators of stress responses and have profound stimulatory effects on cardiovascular function, and dysregulation of adrenergic function has been associated with many adverse cardiac conditions, including congenital malformations, arrhythmias, ischemic heart disease, heart failure, and sudden cardiac death. Despite intensive study, the specific roles these hormones play in the developing heart is not well-understood. Further, there is …

Modulation Of Cholera Toxin Structure And Function By Host Proteins, Helen Burress

Electronic Theses and Dissertations

Cholera toxin (CT) moves from the cell surface to the endoplasmic reticulum (ER) where the catalytic CTA1 subunit separates from the holotoxin and unfolds due to its intrinsic thermal instability. Unfolded CTA1 then moves through an ER translocon pore to reach its cytosolic target. Due to the instability of CTA1, it must be actively refolded in the cytosol to achieve the proper conformation for modification of its G protein target. The cytosolic heat shock protein Hsp90 is involved with the ER-to-cytosol translocation of CTA1, yet the mechanistic role of Hsp90 in CTA1 translocation remains unknown. Potential post-translocation roles for Hsp90 …

Evaluation Of Wild Yam (Dioscorea Villosa) As A Demethylating Agent And Its Anti Metastatic Activity In Human Breast Cancer Cells, Pranapda Aumsuwan

Electronic Theses and Dissertations

No abstract provided.

Characterization Of Prolylcarboxypeptidase Expression Pattern In Rat Cardiomyocytes In Nutrition Overload Conditions, Tahmineh Tabrizian

Electronic Theses and Dissertations

Prolylcarboxypeptidase (PRCP) is a serine protease that cleaves the last amino acid at the carboxy-terminus of peptides with a penultimate proline such as angiotensin II (Ang II), angiotensin III (Ang III), prekallikrein (PK) and α-melanocyte-stimulating-hormone (1-13) (α-MSH1-13). By inactivating Ang II and Ang III, PRCP promotes vasodilation and insulin sensitivity. As well by activating PK, PRCP increases nitric oxide (NO) generation and vasorelaxation through bradykinin (BK) liberation from high molecular weight kininogen (HK). PK is activated to kallikrein by PRCP, implicating a role for PRCP in the coagulation pathway. The resultant kallikrein will activate FXII which in a reciprocal manner …

Cerium Oxide Nanoparticles: Their Phosphatase Activity And Its Control, Atul Dhall

Electronic Theses and Dissertations

Cerium oxide nanoparticles are established scavengers of reactive oxygen and nitrogen species. They have many potential biomedical applications that depend on their physicochemical properties and mode of preparation. Recent studies have found these nanoparticles possess phosphatase mimetic activity. Studying such catalytic activities will qualify their biomedical applications and render information on their bioavailability and potential toxicity. Two oxidation states of cerium exist in these nanoparticles (3+ or 4+). It is hypothesized that the oxidation state of cerium in the nanoparticles determines the amount of adsorbed water on the crystal lattices. This in turn governs their activity as phosphatases. Nanoparticles with …

The Anti-Toxin Properties Of Grape Seed Phenolic Compounds, Patrick Cherubin

Electronic Theses and Dissertations

Corynebacterium diphtheriae, Pseudomonas aeruginosa, Ricinus communis, Shigella dysentariae, and Vibrio cholerae produce AB toxins which share the same basic structural characteristics: a catalytic A subunit attached to a cell-binding B subunit. All AB toxins have cytosolic targets despite an initial extracellular location. AB toxins use different methods to reach the cytosol and have different effects on the target cell. Broad-spectrum inhibitors against these toxins are therefore hard to develop because they use different surface receptors, entry mechanisms, enzyme activities, and cytosolic targets. We have found that grape seed extract provides resistance to five different AB toxins: diphtheria toxin (DT), P. …

Molecular Phylogenetic Relationships Of North American Dermacentor Ticks Using Mitochondrial Gene Sequences, Kayla L. Perry

Electronic Theses and Dissertations

Dermacentor is a recently evolved genus of hard ticks (Family Ixodiae) that includes 36 known species worldwide. Despite the importance of Dermacentor species as vectors of human and animal disease, the systematics of the genus remain largely unresolved. This study focuses on phylogenetic relationships of the eight North American Nearctic Dermacentor species: D. albipictus, D. variabilis, D. occidentalis, D. halli, D. parumapertus, D. hunteri, and D. andersoni, and the recently re-established species D. kamshadalus, as well as two of the Neotropical Dermacentor species D. nitens and D. dissimilis (both formerly Anocentor). We sequenced portions of the mitochondrial …