Molecular Biology Commons^™

The Regulation Of Microrna Biogenesis By Ribosome-Interacting Proteins, Brian Pickering

Dissertations and Theses (Open Access)

MicroRNA (miRNA) are small, non-coding RNAs that affect gene expression through degradation of complementary mRNA targets or inhibition of translation. As they affect approximately 50% of all cellular processes, miRNA are tightly regulated by the cell through transcriptional and post-transcriptional mechanisms. Transcribed miRNA are capped and polyadenylated (referred to as pri-miRNA) which are cleaved by Drosha and DGCR8 to generate 60-90 nucleotide precursor miRNA. The precursors are cleaved again by Dicer and loaded into the RNA-induced silencing complex (RISC) of which Argonaute 2 is the functional component. Many of the proteins involved in miRNA biogenesis share a common role in …

The Mechanism Of Small Rna Biogenesis, Degradation, And Function In Arabidopsis, Meng Xie

School of Biological Sciences: Dissertations, Theses, and Student Research

Eukaryotic small RNAs play important roles in many biological processes through sequence-specific RNA silencing. In plants, there are mainly two small RNAs triggering gene silencing: microRNAs (miRNAs) and small interfering RNAs (siRNAs). The biogenesis and precise regulation of small RNA abundance are crucial for plant growth, development, genomic stability, and the resistance to both abiotic and biotic stresses. In this study, we used Arabidopsis thaliana, the model plant, to study the mechanism of RNA-directed DNA methylation (RdDM), in which siRNAs can trigger DNA methylation and gene silencing. In addition, we investigated the mechanism of miRNA biogenesis and degradation. For …

Clpxp Modulates Cell Growth And Morphology In Cell Shape Mutants Of E.Coli, Ryann Murphy

Senior Honors Projects

ClpXP modulates cell growth and morphology in cell shape mutants of E. coli

Ryann Murphy¹ and Jodi L. Camberg¹

¹University of Rhode Island, Department of Cell and Molecular Biology, Kingston, RI, 02881

Penicillin Binding Proteins (PBPs) are a family of prokaryotic membrane proteins named for their propensity to bind the antibiotic penicillin and are involved in remodeling and deposition of peptidoglycan. In wild type Escherichia coli cells, the uniform rod shape is conserved across generations. E.coli cells containing multiple deletions of Low Molecular Weight (LMW) PBPs exhibit irregular shapes. LMW PBP5 (dacA) is a potential …

Molecular Analyses Of Microbial Abundance And Diversity In The Water Column Of Anchialine Caves In Mallorca, Spain, Damian Menning, Liana M. Boop, Elaina D. Graham, James R. Garey

International Journal of Speleology

Water column samples from the island of Mallorca, Spain were collected from one site in Cova des Pas de Vallgornera (Vallgornera) and three sites (Llac Martel, Llac Negre, and Llac de les Delícies) in Coves del Drac (Drac). Vallgornera is located on the southern coast of Mallorca approximately 57 km southwest of Coves del Drac. Drac is Europe's most visited tourist cave, whereas Vallgornera is closed to the public. Water samples were analyzed for water chemistry using spectrophotometric methods, by quantitative PCR for estimated total abundance of microbial communities, and by length heterogeneity PCR for species richness and relative species …

Determining The Presence Of Carbapenem Antibiotic Resistance In Clinical Isolates, Fidelis Uzoma Enyinnaya

UNLV Theses, Dissertations, Professional Papers, and Capstones

Carbapenems are β-lactam antibiotics reserved for the treatment of severe microbial infections, especially those targeting the Enterobacteriaceae. Introduced in the 1980s, carbapenems have been used successfully in hospitals, and in the 1990s resistance was discovered. Carbapenem resistance is conferred through the production of carbapenemases. In the U.S., the most common carbapenemase is Klebsiella pneumoniae carbapenemase (KPC). In 2012, the National Healthcare Safety Network reported a carbapenem resistance rate of 13.0% among Klebsiella pneumoniae infections, and indicated that the mortality rate associated with carbapenem resistant Enterobacteriaceae (CRE) infections ranged from 48.0-71.9%. According to the Food and Drug Administration (FDA), carbapenem resistance …

Quorum Sensing Molecules For Unicellular Organisms: Spectroscopic And Computational Study Of Conformational Behavior, Daniel Tollefson

Undergraduate Research Symposium

Quorum sensing plays a vital role in unicellular communications. Until recently, it was thought that unicellular bacteria were non-cooperative; that they did not communicate among each other as a larger community. They do, in fact, communicate via small molecules that are created and released into the extracellular environment. Detailed knowledge regarding the interactions of these quorum sensing molecules (QSM) with the molecular and cellular-scale environments can lead to the manipulation of quorum sensing within a population. The function of these molecules requires that they can readily diffuse through the polar environment of aqueous solution and the nonpolar environment of cell …

Acetobixan, An Inhibitor Of Cellulose Synthesis Identified By Microbial Bioprospecting, Ye Xia, Lei Lei, Chad Brabham, Jozsef Stork, James R. Strickland, Adam Ladak, Ying Gu, Ian Wallace, Seth Debolt

Horticulture Faculty Publications

In plants, cellulose biosynthesis is an essential process for anisotropic growth and therefore is an ideal target for inhibition. Based on the documented utility of small-molecule inhibitors to dissect complex cellular processes we identified a cellulose biosynthesis inhibitor (CBI), named acetobixan, by bio-prospecting among compounds secreted by endophytic microorganisms. Acetobixan was identified using a drug-gene interaction screen to sift through hundreds of endophytic microbial secretions for one that caused synergistic reduction in root expansion of the leaky AtcesA6prc1-1 mutant. We then mined this microbial secretion for compounds that were differentially abundant compared with Bacilli that failed to mimic CBI action …

Structural And Functional Analysis Of Harv1 Lipid Binding, Jamie Francisco

Graduate School of Biomedical Sciences Theses and Dissertations

Cardiovascular disease (CVD) has the highest mortality rate worldwide and is considered epidemic in the United States. Statins as the primary and almost sole method of treatment for cholesterol-related CVD, but they have limitations. Proper sterol transport is needed to maintain normal blood lipid levels. Studies have shown that misregulation of lipid trafficking aids in the progression of CVD and in the activation of the unfolded protein response (UPR). Misregulation of lipid and sterol homeostasis also results in the loss of lipid rafts, known cellular signaling hubs and major components of ER associated membrane contact sites. Arv1 is a highly …

Section Abstracts: Biology With Microbiology And Molecular Biology

Virginia Journal of Science

Abstracts of the Biology with Microbiology and Molecular Biology Section for the 92nd Annual Meeting of the Virginia Academy of Science, May 13-15, 2014, Virginia Commonwealth University, Richmond, Virginia

Neurotrophins And Their Effects On Breast Cancer Cell Proliferation And Migration, Kayla Elise Minser

Open Access Theses

Cancer is a large health issue in all parts of the world. In the United States alone, approximately 1 in 4 deaths are cancer related. Breast cancer is a particularly prevalent form, accounting for a little over 14 percent of all cancer incidence. The largest obstacle to overcome for breast cancer morbidity is metastasis. Over 90 percent of all breast cancer related deaths are due to metastasis. Because metastasis is a complex, multi-step process, it is difficult to treat. A recent observation in the Kirshner lab has revealed a type of phenotypic plasticity, where migratory cancer cells have a neuronal-like …

Pharmaceuticals And Personal Care Products: Emerging Contaminants In Aquatic Ecosystems, Jenny E. Zenobio

Open Access Theses

In recent years, the presence of pharmaceuticals and personal care products (PPCPs) in aquatic systems has led to research on their fate and effects. PPCPs have been found in mixture in wastewater effluents, surface, ground, and drinking water at low concentrations from areas of intense urbanization. Although adverse effects to human health from the current environmental concentrations are unlikely, the impacts to ecological receptors are not clear. We performed field and laboratory studies to quantify and evaluate effects of PPCPs on fish. First, a field study was conducted at the Baca National Wildlife Refuge, Colorado (2010-2012) because a portion of …

Carbon Source-Dependent Alteration Of Puf3p Activity Mediates Rapid Changes In The Stabilities Of Mrnas Involved In Mitochondrial Function, Melanie Miller, Joseph Russo, Anthony Fischer, Florencia Leban, Wendy Olivas

Biology Department Faculty Works

The Puf family of RNA-binding proteins regulates gene expression primarily by interacting with the 3′ untranslated region (3′ UTR) of targeted mRNAs and inhibiting translation and/or stimulating decay. Physical association and computational analyses of yeast Puf3p identified >150 potential mRNA targets involved in mitochondrial function. However, only COX17 has been established as a target of Puf3p-mediated deadenylation and decapping. We have identified 10 new targets that are rapidly degraded in a Puf3p-dependent manner. We also observed changes in Puf3p activity in response to environmental conditions. Puf3p promotes rapid degradation of mRNA targets in the fermentable carbon source dextrose. However, Puf3p-mediated …

Pathogenic Mechanisms And Signaling Pathways In Plasmodium Falciparum, Jennifer L. Sedillo

USF Tampa Graduate Theses and Dissertations

Plasmodium falciparum is a human intracellular parasite that is the causative agent of a deadly form of malaria. This species alone is responsible for 200 million cases of malaria annually resulting in over 1 million deaths worldwide. The excessive mortality due to P. falciparum infection is due to its ability to cause severe pathogenesis through hyperparasitemia and cytoadherence defined as the ability of infected red blood cells to adhere to host vasculature. Cytoadherence is mediated through the export of parasite proteins to the surface of the infected red blood cell (RBC). Exported proteins have been identified but the pathway for …

Molecular Evidence For Vector Implication Of Onchocerca Lupi In Los Angeles County, Ca, Shanna June Bolcen

USF Tampa Graduate Theses and Dissertations

Onchocerca is a genus of roundworm most commonly associated with the human infection onchocerciasis, or river blindness. While typically a zoonotic infection of ungulate populations, canine cases (Onchocerca lupi) have been identified in the United States and Greece. In 2012, Los Angeles County, Veterinary Public Health Program identified 3 cases of Onchocerca spp. infections in domestic canines. Samples from the ensuing blackfly collections were sent to the Global Health Infectious Disease Research Unnasch Laboratory for parasite isolation and vector species identification. Species-specific primers were designed and optimized for O. lupi using a non- specific cytochrome oxidase (COI) gene target (689bp) …

Sigma Factor N: A Novel Regulator Of Acid Resistance And Locus Of Enterocyte Effacement In Escherichia Coli O157:H7, Avishek Mitra

USF Tampa Graduate Theses and Dissertations

In enterohemorrhagic E. coli (EHEC) sigma factor N (σ^N) regulates glutamate-dependent acid resistance (GDAR) and the locus of enterocyte effacement (LEE), discrete genetic systems required for transmission and virulence of this intestinal pathogen. Regulation of these systems requires nitrogen regulatory protein C, NtrC, and is a consequence of NtrC/σ^N-dependent reduction in the activity of sigma factor S (σ^S). This study elucidates pathway components and stimuli for σ^N-directed regulation of GDAR and the LEE in EHEC. Deletion of fliZ, the product of which reduces σ^S activity, phenocopies rpoN (σ^N) …

Transcriptional Control Of Toxoplasma Development, Joshua Byran Radke

USF Tampa Graduate Theses and Dissertations

Toxoplasma gondii is an obligate intracellular protozoan parasite of animals and man. The asexual life cycle of Toxoplasma involves three very distinct, but tightly coordinated developmental stages. In nature, the sporozoite (contained within an oocyst) and bradyzoite (contained within a tissue cyst) initiate infection of the intermediate host, followed by rapid differentiation into the actively replicating tachyzoite. When countered by an effective host response, the tachyzoite differentiates back into the latent bradyzoite and this unique ability of Toxoplasma to interconvert between the replicating tachyzoite and the latent bradyzoite within a single host is the cause of life long infection. The …

Exploration Of Mutations In Erythroid 5-Aminolevulinate Synthase That Lead To Increased Porphyrin Synthesis, Erica Jean Fratz

USF Tampa Graduate Theses and Dissertations

5-Aminolevulinate synthase (ALAS; EC 2.3.1.37) is a pyridoxal 5'-phosphate (PLP)-dependent enzyme that catalyzes the first committed step of heme biosynthesis in animals, the condensation of glycine and succinyl-CoA yielding 5-aminolevuliante (ALA), CoA, and CO2. Murine erythroid-specific ALAS (mALAS2) variants that cause high levels of PPIX accumulation provide a new means of targeted, and potentially enhanced, photosensitization. Transfection of HeLa cells with expression plasmids for mALAS2 variants, specifically for those with mutated mitochondrial presequences and a mutation in the active site loop, caused significant cellular accumulation of PPIX, particularly in the membrane. Light treatment of HeLa cells expressing mALAS2 variants revealed …

Structural Insights Into The Interaction Between A Potent Anti-Inflammatory Protein, Viral Cc Chemokine Inhibitor (Vcci), And The Human Cc Chemokine, Eotaxin-1, Nai-Wei Kuo, Yong-Guang Gao, Megan Schill, Nancy Isern, Cynthia Dupureur, Patricia Liwang

Chemistry & Biochemistry Faculty Works

Chemokines play important roles in the immune system, not only recruiting leukocytes to the site of infection and inflammation but also guiding cell homing and cell development. The soluble poxvirus-encoded protein viral CC chemokine inhibitor (vCCI), a CC chemokine inhibitor, can bind to human CC chemokines tightly to impair the host immune defense. This protein has no known homologs in eukaryotes and may represent a potent method to stop inflammation. Previously, our structure of the vCCI·MIP-1β (macrophage inflammatory protein-1β) complex indicated that vCCI uses negatively charged residues in β-sheet II to interact with positively charged residues in the MIP-1β N …

Molecular Pap Biomarkers For Cervical Cancer Risk Assessment In Thinprep® Clinical Specimens, Jennifer Taylor

Graduate School of Biomedical Sciences Theses and Dissertations

Approximately 500,000 patients are diagnosed with cervical cancer worldwide each year, thus making it the second most common cause of cancer-related deaths in women. Persistent high-risk human papillomavirus (HR-HPV) infections induce cervical dysplasia by increasing the expression of two viral oncogenes, E6 and E7. Utilization of the Papanicolaous smear test (Pap test) has contributed to a decrease in morbidity and mortality of cervical cancer; however, subjective analysis of cell morphology with a limited amount of cells has led to a substantial rate of false positive and false negative diagnoses. A more objective and sensitive diagnostic tool for the detection of …

A Lipid-Rich Gestational Diet Predisposes Offspring To Nonalcoholic Fatty Liver Disease: A Potential Sequence Of Events, Alexandria N. Hughes, Julia Thom Oxford

Biomedical Research Institute Publications and Presentations

Nonalcoholic fatty liver disease (NAFLD) is the hepatic manifestation of metabolic syndrome. It affects 20%–30% of the US population, and it is increasing worldwide. Recently, the role of lipid-rich maternal gestational nutrition in spurring the development of NAFLD among offspring has been indicated. Fetal predisposition to NAFLD involves numerous physiological reroutings that are initiated by increased delivery of nonesterified fatty acids to the fetal liver. Hampered ß-oxidation, uncontrolled oxidative stress, increased triacylglycerol synthesis, and the endoplasmic reticulum unfolded protein response are all implicated in sculpting a hepatic phenotype with a propensity to develop NAFLD in the postnatal state. This review …