Molecular Biology Commons^™

Characterization And Genomic Analysis Of Two Escherichia Coli O157:H7 Bacteriophages Isolated From Pigeons, Mohamad I. Alolama

Dissertations

Enterohemorrhagic Escherichia coli, also known as EHEC, is a subset of Shiga toxin-producing E. coli (STEC), and it has recently been identified as one of the principal foodborne pathogens. E. coli O157:H7 is the most important serotype of STEC for its role in causing foodborne illnesses. E. coli O157:H7 could cause various gastroenteritis symptoms such as diarrhea, hemolytic uremic syndrome, hemorrhagic colitis, and thrombotic thrombocytopenic purpura and may cause death. Elimination of E. coli O157:H7 during food processing and storage is a possible solution. Bacteriophages have a significant impact on bacterial populations in nature due to their ability to …

Delineating The Exocytic Fusion Machinery Required For Mast Cell Exocytosis, Pratikshya Adhikari

Dissertations

Mast cells undergo exocytosis to release a wide array of inflammatory mediators by utilizing membrane fusion proteins-SNAREs (soluble-N-ethyl-maleimide sensitive factor attachment protein receptor) along with essential regulatory Munc18 and Munc13 proteins. Accumulating evidence in mast cell biology suggests the existence of distinct pools of mast cell mediators. However, the precise mechanism underlying the release of each mast cell mediator is not clear. To determine whether different exocytic machineries are required for differential mediator release, I used reconstitution to investigate the differential role of Munc18s in fusion machinery regulation. Munc18a and Munc18c stimulated VAMP2 and VAMP3-mediated lipid mixing, whereas Munc18b only …

Dicer Represses Antiviral Innate Immunity Pathways In Mouse Embryonic Stem Cells, Chandan Gurung

Dissertations

Recent studies have demonstrated that embryonic stem cells (ESCs) are deficient in expressing type I interferons (IFN), the cytokines that play key roles in antiviral responses. However, the underlying molecular mechanisms and biological implications of this finding are poorly understood. In this study, I used a synthetic RNA-based assay that can simultaneously assess multiple forms of antiviral responses in ESCs. Dicer is an enzyme essential for RNA interference (RNAi), which is used as a major antiviral mechanism in invertebrates but not clear in vertebrates. RNAi activity is detected in wild-type ESCs but is abolished in Dicer knockout ESCs (D−/−ESCs) as …

Molecular Mechanism Of Action Of The Natural Polyphenolic Compound And The P300 Inhibitor “Carnosol” Against The Triple Negative Breast Cance, Halima Ali Mohammed Salem Alsamri

Dissertations

Carnosol, a naturally occurring Phyto polyphenol found in sage, oregano, and rosemary, has been extensively studied by our laboratory for its anticancer effects in various types of cancer. In human Triple-Negative Breast Cancer (TNBC), carnosol was shown to inhibit cellular viability, colony growth, induced cell cycle arrest, autophagy, and apoptosis. Nonetheless, very little is known about the molecular mechanism of action. In the current study, the ability of carnosol to inhibit metastasis and tumour growth was examined. Wound healing and invasion assays revealed that carnosol inhibited migration and invasion at non-cytotoxic concentrations of MDA-MB-231 cells. Also, carnosol was found to …

Human 5’-Tailed Mirtrons Are Processed By Rnasep, Mohammad Farid Zia

Dissertations

Approximately a thousand microRNAs (miRNAs) are documented from human cells. A third appear to transit non-canonical pathways that typically bypass processing by Drosha, the dedicated nuclear miRNA producing enzyme. The largest class of non-canonical miRNAs are mirtrons which eschew Drosha to mature through spliceosome activity. While mirtrons are found in several configurations, the vast majority of human mirtron species are 5’-tailed. For these mirtrons, a 3’ splice site defines the 3’ end of their hairpin precursor while a “tail” of variable length separates the 5’ base of the hairpin from the nearest splice site. How this tail is removed is …

Roles Of Phospholipases And Ribosomal S6 Kinase In Lipid Remodeling And Growth In Arabidopsis Response To Phosphate Deprivation, Yuan Su

Dissertations

Phosphate (Pi) is one of three macronutrients for plants, which is vital for plant growth and development. Understanding the mechanism by which plants respond and adapt to Pi deficiency not only unveils functions of genes and pathways involved, but also provides potential tools to manipulate crops to better stand Pi stress in low Pi-containing lands. One of the significant metabolic changes in plants under Pi starvation is the membrane lipid remodeling that converts Pi-containing lipids such as phospholipids to Pi-free lipids, such as glycolipids. To elucidate the metabolism and regulation of lipid remodeling, this dissertation characterizes the role of two …

Uncovering The Identity And Metabolism Of Bacterial Coa-Rna, Joseph R. Spangler

Dissertations

Coenzyme A is an indispensable molecule in all known life with roles in metabolism, gene regulation, and macromolecule synthesis. As CoA is derived from RNA itself, it’s incorporation into RNA by in vitro methods has proven useful in research probing the origin of life based on the RNA World theory. The discovery in contemporary bacteria of RNA modified with CoA, however, provided an unexpected twist to previously well-characterized bacterial systems. The identity of sequences associated with CoA-RNA has been elusive since their discovery in 2009 based on the difficulties in isolation while maintaining RNA quality. The aim of this study …

Antiviral Responses In Mouse Embryonic Stem Cells: Differential Development Of Cellular Mechanisms In Type I Interferon Production And Response, Ruoxing Wang

Dissertations

Embryonic stem cells (ESCs) have been recognized as a promising cell source for regenerative medicine. Intensive research over the past decade has led to the possibility that ESC-derived cells will be used for the treatment of human diseases. However, increasing evidence indicates that ESC-derived cells generated by the current differentiation methods are not fully functional. It is recently recognized that ESC-derived cells lack innate immunity to a wide range of infectious agents and inflammatory cytokines. When used in patients, ESC-derived cells would be placed in wounded sites that are exposed to various pathogens and inflammatory cytokines; therefore, their viability and …

Characterization Of Molecular Events Following Heavy Metal Cadmium Exposure: A Cellular Regulatory Symphony In Response To Early Cadmium Insult, Chin-Ju Jean Hsiao

Dissertations

Cadmium, a non-essential toxic heavy metal, has been classified as a human carcinogen and one of the most hazardous substances in our environment. Since it can circulate within the food chain, has a long biological half-life and can bio-accumulate, it has the potential to induce detrimental health effects linked to toxicity, cancer and chronic diseases.

In recent years progress has been made to dissect and understand the molecular mechanisms underlying the effects of cadmium exposure. However, few studies have focused on investigating potential protective and/or defense mechanisms naturally applied by cells upon initial exposure, prior to any damage or toxic …