Life Sciences Commons^™

Role Of Mir-155 And Mir-146a In Mast Cell Function, Amina Abdul Qayum

Theses and Dissertations

Mast cells are resident immune cells abundantly found in the tissue at the host-environment interface, where they play a critical role in inflammatory allergic responses. Mast cell responses may be regulated by the cytokine milieu at the site of inflammation. Recent studies have revealed microRNAs to be important in altering cytokine signaling in immune cells. Here, we demonstrate for the first time that IL-10 and IL-33 induce miR-155 and miR-146a, respectively, to alter mast cell functions. We report that IL-10 enhanced IgE induced activation of mast cells. IL-10 effects are dependent on Stat3 activation, which elicits miR-155 expression, resulting in …

Nitrosative Stress Sensing In Porphyromonas Gingivalis: Structure And Function Of The Heme Binding Transcriptional Regulator Hcpr, Benjamin R. Belvin

Theses and Dissertations

Porphyromonas gingivalis, a Gram negative anaerobe implicated in the progression of periodontal disease, is capable of surviving and causing infection despite high levels of reactive nitrogen species found in the oral cavity due to its efficient nitrosative stress response. HcpR is an important sensor-regulator that plays a vital step in the initiation of the nitrosative stress response in many Gram negative anaerobic bacteria. We employ a combination of X-ray crystallography, SAXS, resonance Raman spectroscopy, UV-Vis spectroscopy, and molecular biology techniques to better understand this key regulator. Knockout of the hcpR gene in W83 P. gingivalis results in the inability of …

Discovery And Characterization Of Bile Acid And Steroid Metabolism Pathways In Gut-Associated Microbes, Spencer Harris

Theses and Dissertations

The human gut microbiome is a complex microbial ecosystem residing in the lumen of our gastrointestinal tract. The type and amounts of microbes present in this ecosystem varies based on numerous factors, including host genetics, diet, and environmental factors. The human gut microbiome plays an important role in normal host physiological functions, including providing energy to colonocytes in the form of short-chain fatty acids. However, gut microbial metabolites have also been associated with numerous disease states. Current tools for analyzing the gut microbiome, such as high-throughput sequencing techniques, are limited in their predictive ability. Additionally, “-omic” approaches of studying the …

Tissue Factor Expression, Regulation, And Signaling In Human Airway Cells, Michael D. Davis

Theses and Dissertations

Rationale: Tissue Factor (TF) is a transmembrane glycoprotein that canonically functions as the initiator of the coagulation cascade. Increased levels of TF have been associated with inflammatory airway diseases. Since lipopolysaccharide (LPS) is known to elicit and inflammatory response in airway epithelium, we hypothesized that airway epithelial cells release TF when exposed to LPS. Since TF aids in local wound healing, we also hypothesized that inhibition of TF would decrease NHBE growth. The specific aim of this work was to evaluate the effects of LPS exposure on TF production and release from airway epithelia and determine the signaling pathways involved. …

The Effects Of Disturbance And Species Specific Interactions On Diversity In An Agent Based Forest Simulation, Matthew E. Mills

Theses and Dissertations

In ecology literature, there is much data which suggests that conspecific negative density dependence (CNDD) and abiotic disturbances increase biodiversity in forests. This thesis elucidates the notion that not only do these two forces increase diversity, but they may also interact with one another in order to achieve higher levels of biodiversity. Abiotic disturbances, like fires and hurricanes, can indirectly impact conspecific effects because when these forces remove individuals from the landscape, the role of the conspecific effects will change. The interaction of these two factors in biodiversity are explored in an agent based forest simulation through a resource surface. …

Deletion Of Cardiac Mir-17-92 Cluster Increases Ischemia/ Reperfusion Injury Via Pten Upregulation, Meeta B. Prakash

Theses and Dissertations

The miR-17- 92 cluster is necessary for cell proliferation and development of the cardiovascular system. Deletion of this cluster leads to death in neonatal mice. The role of this cluster still needs to be defined following ischemia and reperfusion. Methods and Results: Adult male mice were injected with Tamoxifen- was to induce inducible cardiac-specific miR-17- 92-deficient (miR-17- 92-def: MCM:TG:miR-17- 92 flox/flox ) and wild type (WT: MCM:NTG:miR-17-92 flox/flox ) mice were subjected to 30 minutes of myocardial ischemia via left anterior descending coronary artery ligation followed by reperfusion for 24 hours. Post I/R survival (48%) and ejection fraction were reduced, …

Pnpase In C. Elegans: Mutagenic Analysis To Complement Knockdown Studies, Danielle K. Seibert

Theses and Dissertations

PNPase is a gene implicated as a potential target for cancer therapy; human mutations also present with deafness, myopathies, and neuropathies. In this study, C. elegans was used to investigate the effect of knocking out PNPase in a whole animal. C. elegans knockdown studies have reported an extended lifespan via an increase in ROS production. Further noted are larger mitochondria and an increase in fzo-1 expression. Knockout animals previously constructed using CRISPR/Cas9 were used for this study. We aimed to confirm these findings validating previous studies. It was discovered that PNPase knockout animals demonstrated a similar lifespan extension that was …

Optimization Of In Vitro Transcription/Translation Conditions For In Vitro Compartmentalization Studies And Synthesis Of 4-Fluorohistidine, Christine Ring

Theses and Dissertations

Genetic code expansion allows the incorporation of non-canonical amino acids with a variety of new functional groups: fluorescent amino acids,^1-3 azides,^4-6 alkynes,^5-10 and photocrosslinkers.^4,11,12 This incorporation requires the evolution of new tRNA/aminoacyl tRNA sythetase pairs. Traditionally screenings of novel tRNA/aminoacyl tRNA synthetase pairs have been done in vivo. While these in vivo screenings have proven robust, they are limited in multiple ways: non-canonical amino acids (ncAAs) must be nontoxic and bioavailable. Furthermore, library size is limited by transformation efficiency. Lastly, in vivo screenings require substantial amounts of the target ncAA, which is often not available …

Type 2 Immune Responses In The Context Of Helminth Infection, Asthma, Dendritic Cells, And Myeloid Derived Suppressor Cell Function, Sheela Ruby Damle

Theses and Dissertations

Type 2 (T_H2) immune responses evolved to respond to helminth parasite infections by the production of T_H2 cytokines, which stimulate anti-helminth immunity. Macrophage migration inhibitor factor (MIF) is a pleiotropic cytokine, which is produced by many cell types. We demonstrate that mice deficient in MIF have enhanced clearance of a helminth parasite. MIF deficiency in CD4⁺ T cells was found to be the most important for mediating parasite clearance. We mimicked MIF deficiency by administering an inhibitor of the MIF tautomerase activity, sulforaphane, and this also increased parasite clearance (Section I).

T_H2 immune …

Biochemical Analysis Of Putative Single-Stranded Nucleic Acid Binding Proteins In Porphyromonas Gingivalis, Steve H. Kokorelis

Theses and Dissertations

Proteins that bind to both DNA and RNA embody the ability to perform multiple functions by a single gene product. These nucleic acid binding proteins in prokaryotes can play a vital role in many cellular processes, including replication, transcription, gene expression, recombination, and repair, to name a few. Nucleic acid binding proteins have unique functional characteristics that stem from their structural attributes that have evolved in a widely-conserved manner. In Escherichia coli (E. coli), the highly-conserved histone-like protein, HU, which predominates as a heterodimer of HUα and HUβ, has been found to bind to both dsDNA and ssDNA. …

Characterizing The Role Of Key Planar Cell Polarity Pathway Components In Axon Guidance, Grayland W. Godfrey Ii

Theses and Dissertations

An essential process to the development of the neural network of the nervous system is axon guidance. The noncanonical Wnt/Planar Cell Polarity pathway has been identified as an integral component in controlling the projection of axons during axon guidance. Prickle, ROR1 and ROR2 are PCP related proteins that do not have clearly defined roles in the process. This study aims to use zebrafish CoPA neurons as a model to study the roles of Prickle, ROR1, and ROR2 in axon guidance. Using in situ hybridization, morpholino knockdown, and CRISPR/Cas9 loss of function experiments were able to identify ror1, ror2 and …

Relb Acts As A Molecular Switch To Drive Chronic Inflammation In Glioblastoma Multiforme (Gbm)., Michael R. Waters

Theses and Dissertations

Inflammation is a homeostatic response to tissue injury or infection, which is normally short- lived and quickly resolves to limit tissue damage. In contrast, chronic inflammation has been linked to a variety of human diseases, including cancers such as glioblastoma multiforme (GBM). GBMs are very aggressive tumors with very low patient survival rates, which have not improved in several decades. GBM tumors are characterized by necrosis and profound inflammation; with cytokines secreted by both GBM cells and the tumor microenvironment. The mechanisms by which chronic inflammation develops and persists in GBM regardless of multiple anti-inflammatory feedback loops remain elusive. This …

Role Of Mitochondrial Beta-Oxidation In Ethanol Response: A Candidate Gene Study Using Caenorhabditis Elegans, Harini Pallikarana Tirumala

Theses and Dissertations

Alcohol use disorder (AUD) is the fourth leading cause of preventable death in the United States, and the fifth leading risk factor for premature death and disability, globally. There are currently very few treatment options for AUD and there is a need for effective preventive and treatment strategies for this condition. AUD risk has a significant hereditary component, with the contribution of genetic factors being estimated to be about 50%. The Davies-Bettinger laboratory uses C. elegans as a model organism to study the contribution of genetic factors in modulating neuronal responses to ethanol. In this project, we examined the role …

Mast Cell Activation By Diverse Stimuli Can Be Suppressed By Steroid Therapy And Targeting The Fyn-Stat5b Cascade, Anuya Paranjape

Theses and Dissertations

Mast cells are critical effectors of allergic disease that can be activated by numerous stimuli. We have examined mast cell control by the inflammatory cytokine, IL-33, as well as IgG. In the first study reported here, we found that the synthetic glucocorticoid, dexamethasone, potently and rapidly suppressed IL-33-induced cytokine production from murine bone marrow–derived and peritoneal mast cells, as well as human mast cells. Dexamethasone also antagonized IL-33-mediated enhancement of IgE-induced cytokine production and migration. Although dexamethasone had no effect on IL-33-induced phosphorylation of MAP kinases or NFκB p65 subunit, it antagonized AP-1 and NFκB-mediated transcriptional activity. Finally, intraperitoneal administration …

Come Fly With Me: Using Amixicile To Target Periodontal Pathogens And Elucidating The Innate Immune Response In Drosophila Melanogaster, Kathryn Sinclair

Theses and Dissertations

Periodontal diseases (PD) affect 46% of American adults over age 30. These diseases cause symptoms including bleeding and swelling of the gums, bone resorption, and tooth loss, that affect quality of life and have a high economic burden. Periodontal diseases are caused by an imbalance in the oral microbiome, from a healthy state that contains anti-inflammatory commensals like Streptococcus gordonii and mitis, to a diseased state that has pro-inflammatory anaerobic pathogens including Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum, and Tannerella forsythia. The latter initiate disease progression in the oral cavity. However, it’s the host immune …

Ca2+/Calmodulin-Dependent Protein Kinase Type Ii (Camk-Ii) Is Required For Hematopoietic Stem Cell Specification, Camden E. Kurtz

Theses and Dissertations

Ca2+/Calmodulin-dependent protein kinase type II (CaMK-II) is a Serine/Threonine protein kinase that is activated by Ca2+ and Calmodulin to phosphorylate substrates involved in myriad developmental processes. This project implicates CaMK-II in specification of HSCs, and zebrafish provide an ideal embryonic model to study hematopoiesis. Zebrafish genetic manipulation was achieved through: incubation in chemical inhibitors; injection of notochord-targed WT and DN CaMK-II constructs with Transposase; and injection of camk2g1 translation-blocking morpholino antisense oligonucleotide (MO). Whole-mount in situ hybridization (WISH) and immunolocalization on zebrafish embryos allowed visualization of key HSC markers and pathway components that implicated CaMK-II in the specification of HSCs. …

Hydrogen Sulfide Regulation Of Kir Channels, Junghoon Ha

Theses and Dissertations

Inwardly rectifying potassium (Kir) channels establish and regulate the resting membrane potential of excitable cells in the heart, brain and other peripheral tissues. Phosphatidylinositol- 4,5-bisphosphate (PIP2) is a key direct activator of ion channels, including Kir channels. Gasotransmitters, such as carbon monoxide (CO), have been reported to regulate the activity of Kir channels by altering channel-PIP2 interactions. We tested, in a model system, the effects and mechanism of action of another important gasotransmitter, hydrogen sulfide (H2S) thought to play a key role in cellular responses under ischemic conditions. Direct administration of sodium hydrogen sulfide (NaHS), as an exogenous H2S source, …

N-Alkyl 4-Methylamphetamine Enantiomers And The Implication For Potential Modulation Of Abuse Liability And Enhancement Of Psychoactive Drug Targeting., Ramsey Sitta

Theses and Dissertations

Drugs of abuse have a long history in humanity. Currently however, a subject of great interest is the phenylalkylamine family of drugs. Not only is the abuse liability of interest but also the potential therapeutic expansion of the capabilities of this family of drugs by utilizing the unique stereospecific effects of the newly discovered hybrid compounds. Based upon prior data of N-Alkyl 4-MA the enantiomers of N-Methyl, N-Ethyl, and N-Propyl were analyzed in hDAT, hNET, and hSERT. It was found that there was a negative correlation between chain length and potency and dopaminergic component. In agreement with the currently established …

Zebrafish (Danio Rerio) As A Model For Orofacial Research, Kevin A. Ghaffari

Theses and Dissertations

Across species, the face and more specifically the mouth, serves as an essential facet of everyday life. Amongst humans the mouth serves as a tool for the ingestion of food, a marker for facial recognition and a medium for communication. In order for the mouth to properly form, a series of precise growth and fusion events are needed. In order to insure that these events are orchestrated properly is a wide array of signals, transcription factors and epigenetic regulators. Due to the needed precision of these events, congenital birth defects of the face such as cleft lip and cleft palate …

Pelagic Fish Diversity And Density On And Off Restored Oyster Reef Habitat, Danielle Mcculloch

Theses and Dissertations

The heterogeneity provided by structured habitats is important in supporting diverse and dense fish communities. The biogenic reefs created by the native Eastern Oyster, Crassostrea virginica, were once the dominant structural habitat in Chesapeake Bay, and have since declined to less than 1% of historic estimates. Conflicting results on the effects of oyster reef restoration on pelagic fish assemblages make further investigation necessary. Incorporating multiple sampling strategies may help elucidate oyster reef habitat influence on fish assemblages. This study used multi-panel gillnets, hydroacoustic technology, and day-night sampling to describe pelagic fish assemblages on and off oyster reef habitat in the …

Managing Sociality Of A Captive Female Bornean Orangutan From Breeding To Post-Partum At The Smithsonian's National Zoo, Marie Vergamini

Theses and Dissertations

The Association of Zoos and Aquariums’ Orangutan Species Survival Plan® aims to maintain 100 Bornean orangutans (Pongo pygmaeus) in captivity. Because investment in breeding these lineages is high, properly managing sociality of potential mothers is essential. This study assessed how behaviors of a captive breeding female at the Smithsonian’s National Zoo changed from pre-gestation through the offspring’s sixth month of age to improve breeding recommendations.

The infant Bornean orangutan was born September 2016. Results indicate that during breeding, the mother socialized most with two adult females. During pregnancy, the pregnant female socialized in less energy-consuming ways, i.e. grooming. …

The Status Of Snapping Turtles (Chelydra Serpentina) In Virginia: Population Viability, Demography, Regulatory Analysis, And Conservation, Benjamin C. Colteaux

Theses and Dissertations

Snapping turtles (Chelydra serpentina) are being harvested in unprecedented numbers in the United States (US) to meet the needs of international markets. Over three million live snapping turtles from farm and wild caught stock were exported from the US to Asia in 2012-14 alone. In the Commonwealth of Virginia, records indicate that 29,860 snapping turtles were commercially harvested between 2000 and 2015. Size limits are often used to regulate harvest pressure in snapping turtles and other game species. I analyzed the historic harvest of eleven US states to test the efficacy of minimum-size limit regulations at reducing commercial …

The Effect Of Chronic Nutrient Addition From Wastewater On Forest Ecosystems At The Rice Rivers Center, Michael Beck

Theses and Dissertations

Wastewater application to land can be a useful tool for mitigating impacts of nutrient enrichment on aquatic systems. A land application treatment system at VCU’s Rice Rivers Center in Charles City County, VA provided an opportunity to study the impact of wastewater addition on the biogeochemistry of forests representative of the Mid-Atlantic Coastal Plain. Nutrient concentrations in throughfall and leachate were measured at Treatment and Control sites to assess differences in nutrient deposition and retention. Wastewater amended plots from the Walter L. Rice education building received 20-fold (N) and 6-fold (P) higher inputs relative to Control plots and plots located …

Integrating Genetics And Neuroimaging To Study Subtypes Of Binge Drinkers, Megan E. Cooke

Theses and Dissertations

Risky alcohol use is a major health concern among college students, with 40.1% reporting binge drinking (5 or more drinks in one occasion) and 14.4% reporting heavy drinking (binge drinking on 5 or more occasions) in the past month. Risky alcohol use is thought to be the result of a complex interplay between genes, biological processes, and other phenotypic characteristics. Understanding this complex relationship is further complicated by known phenotypic heterogeneity in the development of alcohol use. Developmental studies have suggested two pathways to risky alcohol use, characterized by externalizing and internalizing characteristics, respectively. However, the underlying biological processes that …

The Effects Of The Hiv-1 Tat Protein And Morphine On The Structure And Function Of The Hippocampal Ca1 Subfield, William D. Marks

Theses and Dissertations

HIV is capable of causing a set of neurological diseases collectively termed the HIV Associated Neurocognitive Disorders (HAND). Worsening pathology is observed in HIV+ individuals who use opioid drugs. Memory problems are often observed in HAND, implicating HIV pathology in the hippocampus, and are also known to be exacerbated by morphine use. HIV-1 Tat was demonstrated to reduce spatial memory performance in multiple tasks, and individual subsets of CA1 interneurons were found to be selectively vulnerable to the effects of Tat, notably nNOS+/NPY- interneurons of the pyramidal layer and stratum radiatum, PV+ neurons of the pyramidal layer, and SST+ neurons …

Characterization Of Staphylococcal Nuclease And Tudor Domain Containing Protein 1 (Snd1) As A Molecular Target In Hepatocellular Carcinoma And Non-Alcoholic Steatohepatitis, Nidhi H. Jariwala

Theses and Dissertations

CHARACTERIZATION OF STAPHYLOCOCCAL NUCLEASE AND TUDOR DOMAIN CONTAINING PROTEIN 1 (SND1) AS A MOLECULAR TARGET IN HEPATOCELLULAR CARCINOMA AND NON-ALCOHOLIC STEATOHEPATITIS

Nidhi Jariwala, PhD

A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Integrative Life Sciences

Virginia Commonwealth University, 2017

Devanand Sarkar, M.B.B.S., PhD.

Associate Professor, Department of Human and Molecular Genetics

Virginia Commonwealth University

Richmond, Virginia

SND1, a subunit of the miRNA regulatory complex RISC, has been implicated as an oncogene in hepatocellular carcinoma (HCC). Oncoprotein SND1 regulates gene expression at a post-transcriptional level in multiple cancers including hepatocellular carcinoma (HCC). …

A Study Of Critical Value Notification In The Outpatient Setting: The Relationship Between Physician Response And Patient Outcomes, Kristie Renee Finney

Theses and Dissertations

Critical values are laboratory values that represent a life-threatening condition for which there is a treatment available. Laboratories make immediate notifications to ordering providers when critical values are identified so that they may quickly act to initiate a treatment for their patient. The majority of laboratories apply the inpatient critical value list to the outpatient setting, although there are many differences between an acutely ill inpatient population and an ambulatory outpatient population. The goal of this study was to determine if providers responded to the critical values in the outpatient setting and to determine if there was a difference in …

Orientia Tsutsugamushi Secretes Two Ankyrin Repeat-Containing Effectors Via A Type 1 Secretion System To Inhibit Host Nf-Κb Function, Sean M. Evans

Theses and Dissertations

Scrub typhus is a potentially fatal infection that threatens one billion persons in the Asia-Pacific region and is caused by the obligate intracellular bacterium, Orientia tsutsugamushi. How this organism facilitates its intracellular survival and pathogenesis is poorly understood. Intracellular bacterial pathogens utilize the Type 1 (T1SS) or Type 4 secretion system (T4SS) to translocate ankyrin repeat-containing proteins (Anks) into the host cell to modulate host cell processes. The O. tsutsugamushi genome encodes one of the largest known bacterial Ank libraries as well as Type 1 and Type 4 secretion systems (T1SS and T4SS), which are expressed during infection. In …

Salvianolic Acid B For Pulmonary Delivery Towards Reversal Of Emphysema, Sneha Dhapare

Theses and Dissertations

A new pathobiologic hypothesis has recently emerged that the alveolar structural destruction and loss in emphysema are caused by the deficiency of vascular endothelial growth factor (VEGF). Therefore, this project hypothesized that such pathobiologic VEGF deficiency of emphysematous lungs can be recovered with a natural caffeic acid tetramer, salvianolic acid B (SalB), through activation of signal transducer and activator of transcription 3 (STAT3), so that emphysema can be reversed as a result of inhibition of induced cell death, stimulation of cell proliferation and migration, and promotion of stem cell recruitment to the lungs.

SalB was first shown to be potently …

Niche Conservatism Or Divergence: Insights Into The Evolutionary Histories Of Pinus Taeda, Pinus Rigida, And Pinus Pungens, Constance E. Bolte

Theses and Dissertations

Environmentally related selective pressures and community interactions are well-documented drivers for niche differentiation, as natural selection acts on adaptive traits best fit for survival. Here, we investigated niche evolution between and within Pinus taeda, Pinus rigida, and Pinus pungens and sought to identify which climate variables contributed to species divergence. We also sought to describe niche differentiation across genetic groupings previously identified for P. taeda and P. rigida. Ecological niche models were produced using Maximum Entropy followed by statistical testing based on a measure of niche overlap, Schoener’s D. Both niche conservatism and niche divergence were …