Molecular Biology Commons^™

On The Anti-Adipogenic Function Of Collagen Triple Helix Repeat-Containing Protein 1, Matthew E. Siviski

Electronic Theses and Dissertations

Adipogenesis is regulated by the coordinated activity of adipogenic transcription factors, including PPAR-gamma (PPARG) and C/EBP alpha (CEBPA). Thus, dysregulated adipogenesis predisposes adipose tissues to adipocyte hypertrophy and hyperplasia. We have previously reported that mice possessing a homozygous null gene mutation in collagen triple helix repeat-containing protein 1 (CTHRC1) have increased adiposity compared to wildtype mice, supporting the concept that CTHRC1 regulates body composition. Herein, we investigated the anti-adipogenic activity of CTHRC1. Using 3T3-L1 preadipocytes, we showed significantly reduced adipogenic differentiation in the presence of CTHRC1 commensurate to marked suppression of Cebpa and Pparg gene expression. In addition, CTHRC1 increased …

Endothelial Interleukin-17 Receptor D (Il17rd) Promotes Western Diet-Induced Aortic Myeloid Cell Infiltration, Shivangi Pande

Electronic Theses and Dissertations

The Interleukin-17 (IL17) family is a group of cytokines implicated in the etiology of several inflammatory diseases. Interleukin-17 receptor D (IL17RD), also known as Sef (similar expression to fibroblast growth factor), belonging to the family of IL17 receptors, has been shown to modulate IL17A-associated inflammatory phenotypes. The objective of this study was to test the hypothesis that IL17RD promotes endothelial cell activation and consequent monocyte adhesion. We utilized primary human aortic endothelial cells and demonstrated that RNAi targeting of IL17RD suppressed transcript levels by 83% compared to non-targeted controls. Further, RNAi knockdown of IL17RD decreased the adhesion of THP-1 cells …

The Role Of Foxd1 In Clear Cell Renal Cell Carcinoma, Kyle H. Bond

Electronic Theses and Dissertations

Renal cell carcinoma (RCC) is the 8^th most common cancer in the United States, with the clear cell variant (ccRCC) being the most prevalent. Over 14,000 people die every year to RCC, with rates continuing to increase with an aging general population. Patients suffering from metastatic RCC (mRCC) have extremely poor prognoses, with a 5-year survival of only 11.2%. Current treatment options include resection of primary lesions, tyrosine kinase inhibition (Sunitinib, Pazopanib), mTOR inhibition (Temsirolimus, Everolimus), and immune checkpoint inhibition (Nivolumab, Atezolizumab). Recent attention has been drawn to inhibition of transcription factors like HIF2α (Belzutifan). There is a need …

Computationally Modeling Dynamic Biological Systems, Katherine Jarvis

Electronic Theses and Dissertations

Modeling biological systems furthers our understanding of dynamic relationships and helps us make predictions of the unknown properties of the system. The simple interplay between individual species in a dynamic environment over time can be modeled by equation-based modeling or agent- based modeling (ABM). Equation based modeling describes the change in species quantity using ordinary differential equations (ODE) and is dependent on the quantity of other species in the system as well as a predetermined rates of change. Unfortunately, this method of modeling does not model each individual agent in each species over time so individual dynamics are assumed to …

Deciphering The Perpetual Fight Between Virus And Host: Utilizing Bioinformatics To Elucidate The Host's Genetic Mechanisms That Influence Jc Polyomavirus Infection, Michael P. Wilczek

Electronic Theses and Dissertations

JC polyomavirus (JCPyV) is a human-specific pathogen that infects 50-80% of the population, and can cause a deadly, demyelinating disease, known as progressive multifocal leukoencephalopathy (PML). In most of the population, JCPyV persistently infects the kidneys but during immunosuppression, it can reactivate and spread to the central nervous system (CNS), causing PML. In the CNS, JCPyV targets two cell types, astrocytes, and oligodendrocytes. Due to the hallmark pathology of oligodendrocyte lysis observed in disease, oligodendrocytes were thought to be the main cell type involved during JCPyV infection. However, recent evidence suggests that astrocytes are targeted by the virus and act …

Examining The Function Of Protein Acyltransferase Via The Dhhc Domain Of The Paz5 Protein In The Organism Dictyostelium Discoideum, George M. Stuart-Ranchev

Electronic Theses and Dissertations

Protein S-palmitoylation plays a crucial role in many biological systems. S-palmitoylation involves the post-translational attachment of palmitate to a cysteine residue through a reversible thioester linkage. S-Palmitoylation is used to modify both integral and membrane proteins, many of which are involved in intracellular trafficking, membrane localization, and signal transduction pathways. Intracellular palmitoylation is mediated by a family of protein acyltransferases (PATs). PAT mutations are associated with neurological diseases and cancer progression. Proteins in the PAT family are defined by the presence of a 51-amino acid cysteine-rich domain (CRD), which contains a highly conserved aspartate-histidine-histidine-cysteine (DHHC) motif. The …

Live Cell Super-Resolution Microscopy Quanitifies An Interaction Between Influenza Hemagglutinin And Phosphatidylinositol 4,5-Bisphosphate, Jaqulin N. Wallace

Electronic Theses and Dissertations

Influenza virus, colloquially known as the flu, is an acute respiratory disease that infects several millions of individuals each year in the U.S. and kills tens of thousands of those infected. Yearly viral vaccines are widely available, however, due to the virus’s high mutation rate, their efficacy varies greatly. Due to the variability in vaccine efficiency against seasonal influenza, and the potential for even more pathogenic versions of influenza to emerge at any time, there is a high demand for a universal treatment option.

Influenza virus hijacks a variety of host cell components in order to replicate. The glycoprotein hemagglutinin …

Triclosan Disrupts Immune Cell Function By Depressing Ca2+ Influx Via Acidification Of The Cytoplasm, Suraj Sangroula

Electronic Theses and Dissertations

Triclosan (TCS) is an antimicrobial agent that was effectively banned by the FDA from hand soaps in 2016, hospital soaps in 2017, and hand sanitizers in 2019; however, TCS can still be found in a few products. At consumer-relevant, non-cytotoxic doses, TCS inhibits the functions of both mitochondria and mast cells, a ubiquitous cell type. Via the store-operated Ca²⁺ entry mechanism utilized by many immune cells, mast cells undergo antigen-stimulated Ca²⁺ influx into the cytosol, for proper function. Previous work showed that TCS inhibits Ca²⁺ dynamics in mast cells, and here we show that TCS also inhibits …

Quantification Of Interactions Between Influenza Hemagglutinin And Host Cell Phosphoinositides By Super-Resolution Microscopy, Matthew T. Parent

Electronic Theses and Dissertations

The influenza viral membrane protein hemagglutinin (HA) forms dense nanoscale clusters on host cell plasma membranes (PM), but the mechanisms that direct HA clustering are not well understood. Previous studies have observed HA associated with actin rich regions of the PM, but there are no known direct interactions between HA and actin. Phosphatidylinositol 4,5-biphosphate (PIP2) is a signaling lipid in the PM which can regulate the actin cytoskeleton, and actin comets initiated by PIP2 are known to be exploited by HA to reach the PM of infected cells. PIP2 is also used by other viruses, such as HIV and Ebola, …

Dynamic Regulation Of G-Protein Signaling, William C. Simke

Electronic Theses and Dissertations

G protein-coupled receptors (GPCRs) are involved in numerous signaling processes ranging from neuronal growth to immune cells tracking invaders. GPCR signaling plays a role in many human diseases and thus GPCRs are important drug targets. Yeast respond to mating pheromone using a GPCR signaling system homologous to those used in humans to polarize their cytoskeleton toward the pheromone source. This is accomplished by initializing a MAPK signaling cascade to arrest the cells in mitosis and upregulate expression of chemotropic proteins. Pathway desensitization is accomplished by the Regulator of G-protein Signaling (RGS). RGS abrogates signaling by binding to the active GPCR, …

Thermal And Microbial Effects On Brown Macroalgae: Heat Acclimation And The Biodiversity Of The Microbiome, Charlotte Tc Quigley

Electronic Theses and Dissertations

This dissertation examines effects of stress on brown algal biology from a macroscopic scale by examining the whole aquaculture crops, and at a microscopic level by examining the macroalgal microbiome, across the vertical stress gradient of the intertidal zone and across the latitudes of their biogeographic ranges. Thermal stress negatively affected seedstock gametophytes of the kelp Alaria esculenta isolated from northern and southern locations in Maine. However, previous thermal stress had a positive effect on growth of the next-generation sporophytes. Alaria esculenta has potential as a kelp crop in Maine’s sea vegetable aquaculture sector and implementing this protocol may allow …

Effect Of Arsenic Exposure On Early Eye Development In Zebrafish (Danio Rerio), Remy S. Babich

Electronic Theses and Dissertations

Arsenic is a metalloid that contaminates drinking water supplies worldwide. Due to concerns for human health, the World Health Organization (WHO) and the U.S. Environmental Protection Agency (EPA) have established a safe level in drinking water of ≤ 10 ppb. Arsenic has been shown to have carcinogenic effects in humans at high and low doses. Chronic exposure may result in dermal conditions such as hyperkeratosis and hyperpigmentation. Recently, arsenic exposure has also been linked to lower IQ values in children. The effect of arsenic on neurogenesis, specifically eye development, has not been widely explored. This study aimed to examine the …

Molecular Mechanisms Underlying Toxicant Effects On Mast Cell Signaling And Mitochondria, Juyoung Katherine Shim

Electronic Theses and Dissertations

Mast cells contribute to numerous physiological processes and diseases including immunological and neurological roles. Mast cells degranulate, releasing potent mediators, following signaling transduction initiated by receptor crosslinking. Previously, we showed that the environmental toxicant arsenic and the antibacterial agent triclosan inhibit mast cell degranulation; thus, we have investigated the mechanisms underlying their inhibitory action. We have discovered that arsenic targets early steps in the mast cell signaling pathway: it inhibits phosphorylation of early tyrosine kinase Syk and of Syk’s direct substrate PI3K. Arsenic’s tyrosine phosphorylation inhibition causes inhibition of calcium influx into the cytosol, a key event necessary for degranulation. …

Divergent Responses Of Larval And Juvenile Blue Mussels To Low Salinity Exposure, Melissa A. May

Electronic Theses and Dissertations

In this study, we compared the osmotic stress response of larval and juvenile blue mussels (Mytilus edulis) at the transcriptomic, metabolomic, and whole organism levels. Blue mussels inhabit coastal areas, where they face climate-induced reductions in nearshore salinity. Despite their ecological and economic importance, scientists do not fully understand the underlying transcriptomic and cellular mechanisms of the osmotic stress response in blue mussels or how the ability to respond to stress changes throughout development. Blue mussels spend the first weeks of life developing through several larval stages in the plankton. These early life history stages are more vulnerable …

Dynamic Host-Pathogen Interactions Result In Fungal Epitope Unmasking, Alex Hopke

Electronic Theses and Dissertations

Molecular camouflage is used by a diverse set of pathogens to disguise their identity and avoid recognition by protective host receptors. The opportunistic fungal pathogen Candida albicans is a good example, as it masks the inflammatory component β-glucan in its cell wall to evade detection by the immune receptor Dectin-1. Interestingly, it has been seen that β-glucan becomes unmasked during infection in vivo, though the underlying mechanisms remained unclear. Exposure levels of this epitope may be important, as Dectin-1 mediates protection from some strains of C. albicans and alterations in the organization and composition of the Candida cell wall …

Investigating The Effects Of Particulate Hexavalent Chromium On The Centriole Linkers, Julieta Martino

Electronic Theses and Dissertations

Particulate hexavalent chromium (Cr(VI)) compounds are human lung carcinogens. However, their carcinogenicity is poorly understood. The best model for Cr(VI)-induced carcinogenesis involves the acquisition of structural and numerical chromosome instability (CIN). Many mechanisms contribute to CIN. Among these, centrosomes play a pivotal role because they dictate proper segregation of chromosomes during cell division. Cr(VI) causes centrosome amplification, a phenotype where cells have extra centrosomes and hence can undergo unequal distribution of chromosomes resulting in CIN. How Cr(VI) induces these abnormalities is unknown. Moreover, whether Cr(VI)-induced centrosome amplification is a permanent phenotypic change is also unknown. This work investigates the permanence …

Enabling Sum Frequency Spectroscopy And Fluorescence Correlation Spectroscopy Of Model Cellular Membranes, Sarah M. Sterling

Electronic Theses and Dissertations

The majority of proteins secreted from cells contain a signal peptide sequence that is required for secretion mediated by the endoplasmic reticulum and Golgi apparatus. However, many proteins lack the essential signal peptide sequence, yet still undergo secretion. Such proteins are known to regulate cell proliferation, differentiation, and migration. Fibroblast growth factor 1 (FGF-1) is one protein which undergoes non-classical protein transport. The role of its interactions with the cellular membrane during non-classical protein transport is not fully understood, although FGF-1 has shown preferential destabilizing effects on artificial membranes composed of acidic phospholipids. In the present work, physiologically relevant model …

Physiological And Evolutionary Implications Of The Pattern Of Expression Of Oxygen-Binding Hemoproteins In Antarctic Notothenioid Fishes, Kimberly Borley

Electronic Theses and Dissertations

Antarctic icefish do not express hemoglobin (Hb). Icefishes possess cardiovascular modifications including increased densities of blood vessels, larger ventricles and increased blood volume compared to red-blooded relatives. In addition to delivering oxygen to tissues, Hb degrades nitric oxide (NO), a small signaling molecule. To investigate the mechanism driving development of icefish cardiovascular characteristics, I present and test the hypothesis that loss of Hb results in increased steady-state levels of NO, triggering downstream signaling pathways such as angiogenesis. I measured NO breakdown products, as a proxy for NO, and found that icefish have higher steady-state levels of NO metabolites in their …

Alteration Of Nucleotide Excision Repair By Estrogens: Implications For Carcinogenesis, Emily Glynn Notch

Electronic Theses and Dissertations

Estrogens and estrogen mimics represent a wide range of aquatic contaminants that elicit deleterious effects on exposed organisms. Despite well-characterized reproductive effects of environmental estrogens, less is known about non-reproductive impacts of exogenous estrogen exposure. Additionally, estrogens are known carcinogens, implicated in multiple human cancers. Little or no research has examined the effects of xenoestrogens on DNA repair despite being known carcinogens. The goal of this research was to test the hypothesis that aquatic estrogens enhance the effects of environmental mutagens by altering DNA repair. Of particular interest is nucleotide excision repair (NER), the only repair pathway to remove structurally …

The Ttc7Fsn/Fsn Mutation Results In Hyperactivation Of Lymphocytes And Overproduction Of Il-4 Leading To The Development Of Systemic Autoimmunity, Beth Lindroth Hill

Electronic Theses and Dissertations

Ttc7^fsn/fsn mice exhibit systemic autoimmunity characterized by hyperactivated B cells, increased interleukin-4, autoantibodies, kidney disease and reduced lifespan. Because the pathology is similar to systemic lupus erythematosus, Ttc7^fsn/fsn mice are a useful model with which to study early events that lead to autoimmune disease. Although the Ttc7^fsn mutation has been identified the gene function is unknown. The phenotype of Ttc7^fsn/fsn mice mimics the Th2 autoimmunity of the IL-4 transgenic (Erb et al 1997). It was previously unknown whether the over-production of IL-4 was an intrinsic defect of Ttc7^fsn/fsn lymphocytes that led to autoimmunity, or, whether …

Notch Regulation Of Human Breat Cancer Progression: Contrasting Roles For Notch Signaling, Christine F. O'Neill

Electronic Theses and Dissertations

Notch signaling is associated with activation of either oncogenic or tumor suppressor activities. The human mammary adenocarcinoma cell line, MDA-MB-231, was characterized in vitro and in xenografts in vivo to test the hypothesis that activation of Notch signaling regulates mammary tumor phenotype. Notch 1, Notch2, and Notch4 signaling was compared by stable expression of their constitutively active intracellular domains (ICD). Notch4 activation led to enhanced tumorigenicity, in addition to increased cell proliferation and survival in vitro, whereas the activation of Notch 1 or Notch2 decreased cell proliferation and survival, in which Notch2 increased apoptosis. Stably transfected cell lines were …

Nrage Regulates Life And Death Of Neural Progenitors, Stephen E. Kendall

Electronic Theses and Dissertations

The development of the central nervous system requires the orchestration of numerous instructive and permissive cues. These factors are secreted from signaling centers and function in a concentration dependent manner that effects the proliferation, survival and differentiation of neural progenitors (NP) and their differentiated progeny. The family including bone morphogenetic proteins (BMPs) are key regulators of NP expansion and survival. However, once NP become committed to a neuronal fate and begin to differentiate they compete for limited amounts of neurotrophin that facilitate further growth and survival. Here we show that the p75 neurotrophin receptor interacting protein NRAGE is expressed in …

Cold-Temperature Adaptation Of Muscle Creatine Kinase From An Antartic Teleost (Chaenocephalus Aceratus), Paul Winnard Jr.

Electronic Theses and Dissertations

The white muscle of Chuenocephulus aceratus, an Antarctic teleost of the Channicthyidae family, has a compromised glycoiytic capacity and this fish cannot depend on glycolysis for rapid ATP generation For C. aceratus, creatine kinase (CK) and phosphocreatine (PCr) reserves comprise the metabolic pathway that may supplement and overcome this deficiency in energy transduction. Two conditions, low glycolytic capacity and evolution in a chronically cold habitat (-1.86°C), give us reason to believe that C. aceratus muscle CK (MMCK) has been subjected to strong selective pressure. Thus, the hypothesis of this thesis is that MMCK fiom C. aceratus white muscle …

Detection Of Insulin Receptor, Epidermal Growth Factor Receptor, And Interleukin-6 On Individual Mouse Embryos By Immuno-Polymerase Chain Reaction, Kun Xu

Electronic Theses and Dissertations

Three series of experiments were conducted to: 1) optimize the conditions for the production of pUC19 plasmid and of biotinylated pUC19 fragments; 2) optimize the conditions for the production of protein A-streptavidin chimera (chimeric protein); and 3) detect soluble antigens [bovine serum albumin (BSA) and interleukin-6 (IL-6)] and membrane-bound antigens [insulin receptor and epidermal growth factor receptor (EGFr)] of mouse embryos by immuno-polymerase chain reaction (I-PCR). The first experimental series, which included bacterial culture, chimeric protein purification, and chimeric protein functional experiments, was performed to investigate the effects of IPTG (isopropyl-β-D-thiogalactopyranoside) induction time and temperature, bacterial culture medium, and protein …

Quinic Acid-Mediated Induction Of Hypovirulence And A Hypovirulence-Associated Double-Stranded Rna In Rhizoctonia Solani, Chunyu Liu

Electronic Theses and Dissertations

This study is a part of a project focused on the relationship between dsRNA and hypovirulence in R. solani. Hypovirulence refers to a condition in which a pathogen has a drastically reduced ability to cause disease. Rhizoctonia solani is a soil-borne pathogen causing diseases in numerous plants. Phenyl acetic acid (PAA), a metabolite of phenylalanine, causes Rhizoctonia disease symptoms on potato in the absence of the pathogen itself. The amount of PAA produced by a hypovirulent isolate is 10% of that produced by virulent isolates. A 3.6 kb dsRNA (M2) has been shown to be associated with hypovirulence in …