Medicine and Health Sciences Commons^™

Characterization Of A Novel Protease In Staphylococcus Aureus, Adam L. Johnson

Theses and Dissertations

A newly discovered cysteine protease, Prp, has been shown to perform an essential, site-specific cleavage of ribosomal protein L27 in Staphylococcus aureus. In Firmicutes and related bacteria, ribosomal protein L27 is encoded with a conserved N-terminal extension that must be removed to expose residues critical for ribosome function. Uncleavable and pre-cleaved variants were unable to complement an L27 deletion in S. aureus, indicating that this N-terminal processing event is essential and likely plays an important regulatory role. The gene encoding the responsible protease (prp) has been shown to be essential, and is found in all organisms …

Immunotherapy Of Cancer: Reprogramming Tumor/Immune Cellular Crosstalk To Improve Anti-Tumor Efficacy, Kyle K. Payne

Theses and Dissertations

Immunotherapy of cancer has been shown to be promising in prolonging patient survival. However, complete elimination of cancer and life-long relapse-free survival remain to be major challenge for anti-cancer therapeutics. We have previously reported that ex vivo reprogramming of tumor-sensitized immune cells by bryostatin 1/ionomycin (B/I) and the gamma-chain (γ-c) cytokines IL-2, IL-7, and IL-15 resulted in the generation of memory T cells as well as CD25+ NKT cells and CD25+ NK cells. Adoptive cellular therapy (ACT) utilizing these reprogrammed immune cells protected FVBN202 mice from tumor challenge, and overcame the suppressive functions of myeloid-derived suppressor cells (MDSCs). We then …

Elaboration And Design Of Α7 Nachr Negative Allosteric Modulators, Osama I. Alwassil

Theses and Dissertations

α7 Neuronal nicotinic acetylcholine receptors are one of two major classes of receptors responsible for cholinergic neurotransmission in the central nervous system. The existence of α7 neuronal nAChRs in different regions of the nervous system suggests their involvement in certain essential physiological functions as well as in disorders such as Alzheimer’s disease (AD), drug dependence, and depression. This project was aimed toward the discovery and development of small–molecule arylguanidines that modulate α7 nAChR function with improved subtype-selectivity through an allosteric approach. Identifying the required structural features of these small molecules allowed optimization of their negative allosteric modulator (NAM) actions at …

Elucidation Of A Novel Pathway In Staphylococcus Aureus: The Essential Site-Specific Processing Of Ribosomal Protein L27, Erin A. Wall

Theses and Dissertations

Ribosomal protein L27 is a component of the eubacterial large ribosomal subunit that has been shown to play a critical role in substrate stabilization during protein synthesis. This function is mediated by the L27 N-terminus, which protrudes into the peptidyl transferase center where it interacts with both A-site and P-site tRNAs as well as with 23S rRNA. We observed that L27 in S. aureus and other Firmicutes is encoded with a short N-terminal extension that is not present in most Gram-negative organisms, and is absent from mature ribosomes. The extension contains a conserved cleavage motif; nine N-terminal amino acids are …

Effects Of Hiv-1 Tat On The Enteric Nervous, Joy Ngwainmbi

Theses and Dissertations

More than 1.2 million people are estimated to be currently living with the human immunodeficiency virus (HIV) in the United States of America. The gastrointestinal (GI) tract is both a major target and an important component of HIV pathogenesis. The GI processes that are dysregulated during HIV infection are controlled by the enteric nervous system (ENS). Indeed, both clinical and experimental studies have implicated the ENS in HIV and simian immunodeficiency virus (SIV) pathogenesis. In addition to direct viral effects, the HIV virus also indirectly affects the GI tract via cellular and/or viral toxins released by infected cells. Trans-activator of …

Effects Of Tgf-Β1 And Il-33 On Mast Cell Function, Victor S. Ndaw

Theses and Dissertations

TGFβ is involved in many pathological conditions, including autoimmune disorders, cancer, and cardiovascular and allergic diseases. We have previously found that TGFβ can suppress IgE-mediated mast cell activation in human and mouse mast cells in vitro. IL-33 is a recently discovered member of the IL-1 family capable of inducing mast cell responses and enhancing IgE-mediated activation. In this study, we investigated the effects of TGFβ on IL-33-mediated mast cell activation. Bone marrow-derived mast cells cultured in TGFβ -1, -2, or -3 showed reduced IL-33-mediated production of TNF, IL-6, IL-13 and MCP-1, in a concentration-dependent manner. Furthermore, TGFβ also reduced …

Xlf-Dependent Nonhomologous End Joining Of Complex Dna Double-Strand Breaks With Proximal Thymine Glycol And Screening For Xrcc4-Xlf Interaction Inhibitors, Mohammed Al Mohaini

Theses and Dissertations

DNA double-strand breaks induced by ionizing radiation are often accompanied by ancillary oxidative base damage that may prevent or delay their repair. In order to better define the features that make some DSBs repair-resistant, XLF-dependent nonhomologous end joining of blunt-ended DSB substrates having the oxidatively modified nonplanar base thymine glycol (Tg) at the first (Tg1) , second (Tg2), third (Tg3) or fifth (Tg5) positions from one 3’ terminus was examined in human whole-cell extracts. Tg at the third position had little effect on end-joining even when present on both ends of the break. However, Tg as the terminal or penultimate …

The Characterization Of A Putative Virulence Factor Expressed By Sneathia Amnii, Amy Sanford

Theses and Dissertations

Preterm birth, defined at birth before 37 weeks gestation, affects millions of newborns worldwide every year. Preterm birth is a leading cause of infant morbidity and mortality. One major cause of preterm birth is preterm premature rupture of membranes (PPROM), which can be triggered by bacterial infection and inflammation. A bacterial species that has been implicated in preterm birth and other obstetric complications is Sneathia amnii. The goals of this study were to observe cytopathogenic effects caused by S. amnii strain Sn35 and identify putative virulence factors causing those effects. Sn35 was able to adhere to, invade, and damage/kill …

Proof-Of-Concept Of Environmental Dna Tools For Atlantic Sturgeon Management, Jameson Hinkle

Theses and Dissertations

Abstract

The Atlantic Sturgeon (Acipenser oxyrinchus oxyrinchus, Mitchell) is an anadromous species that spawns in tidal freshwater rivers from Canada to Florida. Overfishing, river sedimentation and alteration of the river bottom have decreased Atlantic Sturgeon populations, and NOAA lists the species as endangered. Ecologists sometimes find it difficult to locate individuals of a species that is rare, endangered or invasive. The need for methods less invasive that can create more resolution of cryptic species presence is necessary. Environmental DNA (eDNA) is a non-invasive means of detecting rare, endangered, or invasive species by isolating nuclear or mitochondrial DNA (mtDNA) from the …

Functional Characterization Of Rai1 In Zebrafish, Joshua S. Beach

Theses and Dissertations

Smith-Magenis Syndrome (SMS; OMIM #182290) is a multiple congenital abnormality and intellectual disability (ID) disorder caused by either an interstitial deletion of the 17p11.2 region containing the retinoic acid induced-1 (RAI1) gene or a mutation of the RAI1 gene. Individuals diagnosed with SMS typically present characteristics such as ID, self-injurious behavior, sleep disturbance, ocular and otolaryngological abnormalities, craniofacial and skeletal abnormalities, neurological and behavioral abnormalities, as well as other systemic defects and manifestations. Previous work by Vyas in 2009 showed temporal expression of rai1 in zebrafish embryos as early as 9 hpf. We hypothesize that there is maternal …

Development Of Non-Traditional Platinum Anticancer Agents: Trans-Platinum Planar Amine Compounds And Polynuclear Platinum Compounds, Daniel E. Lee

Theses and Dissertations

Development of Non-Traditional Platinum Anticancer Agents: trans-Platinum Planar Amine Compounds and Polynuclear Platinum Compounds

By Daniel E. Lee, Ph.D.

A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at Virginia Commonwealth University.

Virginia Commonwealth University, 2015

Major Director: Nicholas P Farrell, Ph.D., Professor, Department of Chemistry

Platinum anticancer compounds with cis geometry, similar to cisplatin, have been explored to circumvent the cisplatin resistance; however, they were not considered broadly active in cisplatin cells due to exhibiting similar or same cell death mechanism as cisplatin. Platinum compounds with trans geometry were less studied …

The Effect Of Statins On Il-33 Mediated Mast Cell Function, Marcela Taruselli

Theses and Dissertations

This study demonstrates original findings of statin effects on IL-33 stimulated mast cells. Statins are a class of drugs used to lower cholesterol production by targeting HMG CoA reductase. These commonly prescribed drugs have been shown to be immunomodulatory. In this study, we have found that pretreatment with statins has a variety of effects on IL-33 stimulated mast cells. Atorvastatin suppresses TNF and IL-6 production, while fluvastatin significantly enhances release of these proinflammatory cytokines in BMMCs. Although they have differing effects on cytokine production, both statins lowered ST2 expression on the cell surface, decreased cell viability, and enhanced expression of …

Interaction Between Atm Kinase And P53 In Determining Glioma Radiosensitivity, Syed F. Ahmad

Theses and Dissertations

Glioblastoma multiforme (GBM) is the most common primary brain tumor. Studies have shown that targeting the DNA damage response can sensitize cancer cells to DNA damaging agents. Ataxia telangiectasia mutated (ATM) is involved in signaling DNA double strand breaks. Our group has previously shown that ATM inhibitors (ATMi) sensitize GBM cells and tumors to ionizing radiation. This effect is greater when the tumor suppressor p53 is mutated.

The goals of this work include validation of a new ATM inhibitor, AZ32, and elucidation of how ATMi and p53 status interact to promote cell death after radiation. We propose that ATMi and …

High-Throughput Data Analysis: Application To Micronuclei Frequency And T-Cell Receptor Sequencing, Mateusz Makowski

Theses and Dissertations

The advent of high-throughput sequencing has brought about the creation of an unprecedented amount of research data. Analytical methodology has not been able to keep pace with the plethora of data being produced. Two assays, ImmunoSEQ and the cytokinesisblock micronucleus (CBMN), that both produce count data and have few methods available to analyze them are considered.

ImmunoSEQ is a sequencing assay that measures the beta T-cell receptor (TCR) repertoire. The ImmunoSEQ assay was used to describe the TCR repertoires of patients that have undergone hematopoietic stem cell transplantation (HSCT). Several different methods for spectratype analysis were extended to the TCR …

Characterizarion Of The Regulation And Function Of Neisseria Gonorrhoeae Tonb-Dependent Transporters: Tdfg, Tdfh And Tdfj, Sophonie Jean

Theses and Dissertations

The obligate human pathogen Neisseria gonorrhoeae successfully overcomes host strategies to limit essential nutrients, termed “nutritional immunity” by expression of TonB-dependent transporters (TdTs): outer membrane receptors that facilitate nutrient transport in an energy-dependent manner. N. gonorrhoeae encodes eight TdTs, five of which facilitate utilization of iron or iron-chelates from host derived proteins including transferrin, lactoferrin and hemoglobin, in addition to siderophores from neighboring bacteria. The transferrin utilization system was previously shown to be critical for establishing infection in human males; demonstrating the possible contributions of TdTs to gonococcal pathogenesis. As such, studies describing the biological function and contribution to pathogenesis …

Dysregulation Of Micrornas In Blood As Biomarkers For Diagnosing Prostate Cancer, Rhonda W. Daniel

Theses and Dissertations

Prostate cancer is the most common noncutaneous cancer among men, yet current diagnostic methods are insufficient and more reliable diagnostic markers need to be developed. The answer that can bridge this gap and enable more efficient diagnoses may lie in microRNAs. These small, single stranded RNA molecules impact protein expression at the translational level and regulate important cellular pathways. Dysregulation of these small RNA molecules can have tumorigenic effects on cells and lead to many types of cancers.

Currently the Prostate-Stimulating Antigen (PSA) is used as a diagnostic marker for prostate cancer. However, many factors can elevate PSA levels such …