Molecular Biology Commons^™

Comparative Genomics And Virulence Studies Of Streptomyces Soil Rot And Scab Pathogen Species, Natasha Soares

LSU Doctoral Dissertations

Comparative genomic analyses were performed to gain insights into the organization and content of the genome of Streptomyces ipomoeae, the soil rot pathogen that infects sweetpotatoes. Unlike Streptomyces scab pathogens, the thaxtomin phytotoxin gene cluster (txt) in S. ipomoeae does not appear to reside within a genomic island and has diverged from its scab pathogen counterparts. Increased usage of the rare TTA codon, particularly for the txt cluster, suggests greater translational control by the bldA tRNA in S. ipomoeae. Orthologous gene searches and secondary metabolite profiling yielded ortholog groups and metabolite gene clusters that were exclusive …

Identification And Characterization Of Genetic Elements That Regulate A C-Di-Gmp Mediated Multicellular Trait In Pseudomonas Fluorescens, Collin Kessler

Electronic Theses and Dissertations

Microbial communities contain densely packed cells where competition for space and resources are fierce. These communities are generally referred to as biofilms and provide advantages to individual cells against immunological and antimicrobial intervention, dehydration, and predation. High intracellular pools of cyclic diguanylate monophosphate (c-di-GMP) cause cells to aggregate during biofilm formation through the production of diverse extracellular polymers. Genes that encode c-di-GMP catalytic enzymes are commonly mutated during chronic infections where opportunists display enhanced resistance to phagocytosis and antibiotics. Our lab uses an emergent multicellular trait in the model organism Pseudomonas fluorescens Pf0-1 to study the emergence of c-di-GMP mutations …

Dysregulation Of Mir-10a Promotes Cancer Features In Cholangiocarcinoma, Matthieu Spriet

Theses & Dissertations

Cholangiocarcinoma is a primary liver cancer of the bile duct epithelium that exhibits microRNA-mediated control of tumor cell signaling. Strides toward new treatment rest on a better defining of cholangiocarcinoma tumor biology including the RNA-based layer of regulation. Additionally, there is a gap in knowledge on microRNA expression in human tissue. While there is RNA-seq data of microRNA expression in tissue, it does not differentiate between cell types, thus leaving unanswered questions about cell specific microRNA biology and expression.

Here, we identify miR-10a as an oncogenic microRNA acting through MAPK signaling. Using cholangiocarcinoma cell lines, we determined miR-10a is an …

Neuropilin-2 In Advanced Prostate Cancer And Its Targeting With Novel Small Molecule Inhibitors, Ridwan Islam

Theses & Dissertations

Despite the development of new therapies, clinical management of advanced metastatic castrationresistant prostate cancer (mCRPC) still remains challenging owing to the emergence of therapy resistance. Resistance to the therapies is driven by both AR and non-AR pathways. Non-AR pathway is characterized by a lineage switch that leads to the development of neuroendocrine-like (NE-like) prostate cancer (PCa), which has a fulminant clinical course due to the lack of effective treatment strategy. Therefore, novel molecular targets need to be identified to develop effective therapeutic regimen to improve the outcomes in advanced PCa patients including NE-like PCa. Recent investigation on advanced PCa patients …

Qualitative Proteomic And Genomic Analysis Of Klebsiella Pneumoniae Bacteriophage Kaomega, Emilee Carr

Undergraduate Honors Theses

Klebsiella pneumoniae is a Gram-negative Enterobacteriaceae that is a common nosocomial pathogen causing pneumonia, infections in the bloodstream, wound infections, and meningitis. It has developed natural resistance to multiple antibiotics, most notably carbapenems which are often seen as the last line of defense against multi-drug resistant pathogens. Bacteriophages are being investigated as a promising alternative treatment to antibiotics in fighting these resistant pathogens. KaOmega, a Klebsiella pneumoniae bacteriophage, was isolated, sequenced, and annotated to characterize and understand its potential for use in a phage therapy. Characterization included Phyre2 analysis to predict putative protein functions based on structural homology, burst size …

Perturbation Modeling For Molecular Design Of Protein Tyrosine Kinase Inhibitors Using Unsupervised Machine Learning, Keerthi Krishnan

Computational and Data Sciences (MS) Theses

The field of computational drug discovery and development has grown, with the aid of new computational tools for novel molecule discovery. In specific, generative deep learning models have excelled as tools to aid in navigating the large space of known molecules and in the creation of new molecules. These models are fed various representations of molecules as inputs and learn to perform a variety of things, such as the optimization of these molecules towards a targeted property. Ultimately, these generative learning models allow us to build bridges between chemical and continuous spaces to understand the compromise between invoking small incremental …

Dual Mechanisms Implemented By Lin-28 For Positive Regulation Of Hbl-1 Are Necessary For Proper Development Of Distinct Tissues In Caenorhabditis Elegans, Madeleine Minutillo

Graduate School of Biomedical Sciences Theses and Dissertations

In Caenorhabditis elegans, the heterochronic pathway is comprised of a hierarchy of genes that control the proper timing of developmental events. hbl-1 (Hunchback Like-1) encodes an Ikaros family zinc-finger transcription factor that promotes the L2 stage cell fate events of the hypodermis. The downregulation ofhbl-1 is a crucial step for the transition from the L2 to the L3 stage. There are two known processes through which negative regulation of hbl-1 occurs: suppression of hbl-1 expression by 3 let-7 miRNAs through the hbl-1 3’UTR and inhibition of HBL-1 activity by LIN-46. The mechanisms by which hbl-1 is positively regulated have not …

The Effects Of Stress On The Mammalian Nucleolus And Ribosome Synthesis, Russell T. Sapio

Graduate School of Biomedical Sciences Theses and Dissertations

Ribosomes are responsible for translating every protein in the cell and are essential in all domains of life. Ribosome biosynthesis (RB) takes place in the nucleolus and is an intricate hierarchical process involving over 200 factors, including ribosomal proteins, ribosomal RNA (rRNA), and trans-acting ribosome biogenesis factors (RBFs). Inhibiting RB can disrupt nucleolar integrity, causing ribosomal- and nucleolar-factors to delocalize. This can stabilize the transcription factor p53, which is normally degraded rapidly, ultimately causing cell cycle arrest or apoptosis, through a mechanism termed the nucleolar stress response (NSR). This thesis explores the effects of inhibiting RB post rRNA transcription and …

Identifying A Glucocorticoid-Activated Gpcr That Rapidly And Non-Genomically Increases Camp Levels In Mammalian Cells, Francisco Nunez

Pharmaceutical Sciences (PhD) Dissertations

Glucocorticoids (GCs) are steroid hormones that regulate diverse physiological processes. Synthetic versions of GCs are commonly used to treat inflammatory diseases such as asthma by modulating gene expression to suppressing several inflammatory activities. However, it is estimated that 5-10% of asthmatics are unresponsive to GCs, which may be explained by receptor desensitization and/or the presence of a neutrophilic endotype. One understudied phenomenon of GCs is their ability to induce rapid, non-genomic actions. For example, GCs can acutely modulate calcium concentrations levels, induce smooth muscle relaxation and modulate nitric oxide synthase activity, within minutes and sometimes seconds, which is too rapid …

Investigating Granulopoiesis Of Neutrophils From Myeloblasts In The Bone Marrow Post Novel Anti-Schistosoma Compound Treatment, Sarah Alsuleiman, Paul Davis

Theses/Capstones/Creative Projects

Schistosomiasis, a commonly neglected tropical disease, is a waterborne parasitic worm infection able to infect through direct skin penetration. This disease affects approximately 270 million people worldwide and ranks only second to malaria as a leading infectious disease. Although some possible alternatives are emerging, currently, the most effective drug treatment is praziquantel (PZQ). However, PZQ is only effective against the adult stage of the worm, allowing juvenile worms to progress in the infection. Additionally, Schistosoma worms are developing resistance to this drug as reduced efficacy has been noted. Thus, the need for drug discovery and testing is increased. SA01, a …

Determining The Full-Length Structure Of Collagenase H Using Small-Angle X-Ray Scattering, Josie Carson

Chemistry & Biochemistry Undergraduate Honors Theses

Known to cause gas gangrene, Hathewaya histolytica secretes two sister collagenases, collagenase G (Col G) and collagenase H (Col H), to degrade the triple helical structure of collagen to further infection in a host. Individual domains of Col H have been crystalized in previous studies, but methods in x-ray crystallization of full-length Col H have been unsuccessful. Using Small Angle X-Ray Scattering (SAXS) data, atomistic modeling was used to generate multiple conformations of Col H while accounting for flexibility between domains. Full-length Col H was found to adopt a two-state conformational model exhibiting a majority compact and a minority elongated …

N6-Methyladenosine Rna Modifications In Myogenesis / Narrative Competence And Cognitive Mapping As A Culturally Sustaining Pedagogy In The Education Of Emergent Bilinguals, Marina Danielle Infantado

Legacy Theses & Dissertations (2009 - 2024)

Myogenesis involves skeletal muscle stem cells (MuSCs) that produce and regenerate skeletal muscle during regular growth and repair. However, when this system fails to function normally, it can lead to musculoskeletal diseases like Duchenne Muscular Dystrophy (DMD). Therefore, it is important to study the molecular mechanisms behind this developmental process in order to seek therapies and solutions for these types of diseases. Our interest lies in the field of epitranscriptomics, which focuses on post-transcriptional ribonucleic acid (RNA) modifications, particularly N6-methyladenosine (m6A), which involves the addition of a methyl group to the adenosine nucleotide, a process that is mediated by the …

Parallel Networks That Govern The Transcriptional Response To Stress, Serene Anne Durham

Legacy Theses & Dissertations (2009 - 2024)

The transcription factor, p53, plays a pivotal role in the oversight of many stimulus-dependent pathways. Its ability to respond to a wide variety of cellular stress stimuli by activating a broad range of target genes has led it to be characterized as a stress-dependent transcription factor. Our research focuses on deconvoluting the varied transcriptional response to distinct stress signals in an attempt to define the regulatory strategies leading to gene activation after cell stress. We have found that distinct stress response networks, some of which are p53-independent, are converging at activation of a common set of target genes. Our data …

A Computational Model Of The Line-1 Retrotransposon Life Cycle And Visualization Of Metabolic Networks In 3-Dimensions., Michael D. Martin

Electronic Theses and Dissertations

Computational modeling of metabolic reactions and cellular systems is evolving as a tool for quantitative prediction of metabolic parameters and reaction pathway analysis. In this work, the basics of computational cell biology are presented as well as a summary of physical processes within the cell, and the algorithmic methods used to find time dependent solutions. Protein-protein and enzyme-substrate interactions are mathematically represented via mass action kinetics to construct sets of linear differential equations that describe reaction rates and formation of protein complexes. Using mass action methods, examples of reaction networks and their solutions are presented within the Virtual Cell simulation …

Investigating The Role Of The Three N-Terminal Hamp Domains Of The Aer2 Chemoreceptor From Pseudomonas Aeruginosa, Selina Anaya

Loma Linda University Electronic Theses, Dissertations & Projects

Pseudomonas aeruginosa is a ubiquitous environmental bacterium and opportunistic human pathogen. It readily adapts to changing environmental conditions with the aid of 26 chemoreceptors that signal to four distinct chemosensory systems. The Aer2 chemoreceptor from P. aeruginosa is an O2 sensor implicated in stress responses, virulence and fine-tuning the chemotaxis (Che) system. Aer2 is the sole chemoreceptor of the Che2 chemosensory system, which forms complexes at the cell pole during stationary phase. Aer2 is soluble, yet membrane-associated and displays an unusual arrangement with its PAS sensing domain sandwiched between three N-terminal and two C-terminal HAMP domains. HAMP domains are widespread …

An Analytical Method To Detect And Quantify Ll-37 In An In Vitro Co-Culture Of Activated Thp-1 Cells And Staphylococcus Aureus, Staphylococcus Epidermidis, And Pseudomonas Aeruginosa, Victoria Hunter

Graduate Theses and Dissertations

Healthcare-associated infections (HCAIs) affect 1.7 million hospitalized patients each year, resulting in over 98,000 deaths and anywhere from $28.4 to $45 billion in treatment costs. Furthermore, it has been established that more than 80% of these infections are caused by biofilms While HCAIs can be bacterial, viral, fungal, or parasitic, there are between 12 and 17 species cause 80 to 87% of all HCAIs. Among the most commonly isolated microorganisms are Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus). Thus, biofilms are of importance not only due to their prevalence in HCAIs but also due to the increased antibiotic …

Examining The Expression Patterns Of Desulfotalea Psychrophila Dsrab Operon And Pit At Subfreezing Temperatures And Different Concentrations Of Sulfate Salts As A Model For Mars And Icy Worlds Survival And Colonization, Sergio Luis Mosquera Mora

Graduate Theses and Dissertations

Since ancient times, Humanity has been fascinated with the idea of what lies beyond the borders of our planet. Fortunately, the combined efforts of many nations have made it possible to send unmanned spacecraft to orbit planets located close to Earth. These missions have the principal goal to collect data that could help us understand the basic environmental conditions that persist on those planets, or for evidence of past or present life. Equally important, landers and rovers have been successfully deployed to start the in-situ exploration of many planets of the Solar System. Among them, Mars has been extensively studied …

Validation Of Whole Genome Resequencing For Mapping The Genetics Of Ascites In Broilers And Viral Susceptibility In Layers, Katherine Pepper Lee

Graduate Theses and Dissertations

This dissertation focused on the efficacy and validity of whole genome resequencing (WGR) for fine mapping genetic determinants of particular traits in a given organism. Previously, our research group used WGR to identify haplotype blocks of single nucleotide polymorphisms associated with ascites resistance with some as strong candidates for use in marker-assisted selection (MAS). Chapter 2 discusses the completion of a MAS project through evaluation of ascites incidence as well as production traits of economic value to poultry producers. Thus, the MAS project also covered viability of this methodology in the industry. The MAS significantly reduced ascites incidence in broilers …

Characterization Of The Wee1 Homologues And The Investigation Of Factors Promoting Cellular Enlargement In Cryptococcus Neoformans, Rodney J. Colón Reyes

All Dissertations

Cryptococcus neoformans is an opportunistic fungal pathogen, infecting mainly immunocompromised individuals. As the main cause of cryptococcosis, it is responsible for over 180,000 deaths every year. As an environmental yeast, it has unique adaptations that allow it to proliferate in the human host. Among these adaptations its capacity to transition to an extreme phenotype known as Titan cells is of special interest to researchers. With sizes above 10 um and able to reach 70 um or more in cell size. This size is accompanied with a large vacuole, larger polysaccharide capsule, and an increased resistance to fluconazole (FLC). FLC is …

Characterization Of Genetic Pathways Involved In Resistance To A Novel Antifungal Peptide, Kayla L. Haberman

Graduate Theses and Dissertations

Antibiotic resistance is increasing prevalence, particularly in Candida glabrata. This opportunistic pathogen is closely phylogenetically related to Saccharomyces cerevisiae; however, its characterization is limited. C. glabrata is only second to Candida albicans as a fungal pathogen in immunocompromised patients. Commonly resistant to azoles, the most common fungal therapy, it has become costly and challenging to treat. A histatin 5 derived antifungal peptide, KM29, has a high degree of efficacy in Candida species and S. cerevisiae. The objective of this work is to advance our understanding of the mechanism of action of KM29 against C. glabrata. Previous work in the lab …

Improved Molecular Detection Tools For The Invasive Crop Pest Helicoverpa Armigera (Hübner), Mitchell D. Rich

All Theses

Helicoverpa armigera is a major crop pest native to Europe, Asia, Australia, and Africa. H. armigera has recently invaded South America and has caused billions of dollars in agricultural losses. It is difficult to differentiate H. armigera from H. zea, a closely-related species native to North and South America. A few genetic tests have been previously developed to detect H. armigera DNA in pooled samples of moth legs. In this study, an improved qPCR melt curve assay with higher detection sensitivity and a field-based recombinase polymerase amplification (RPA) assay were developed for specific detection of H. armigera DNA …

Applications Of Nuclear Magnetic Resonance Spectroscopy: From Drug Discovery To Protein Structure And Dynamics., Mark Vincent C. Dela Cerna

Electronic Theses and Dissertations

The versatility of nuclear magnetic resonance (NMR) spectroscopy is apparent when presented with diverse applications to which it can contribute. Here, NMR is used i) as a screening/ validation tool for a drug discovery program targeting the Phosphatase of Regenerating Liver 3 (PRL3), ii) to characterize the conformational heterogeneity of p53 regulator, Murine Double Minute X (MDMX), and iii) to characterize the solution dynamics of guanosine monophosphate kinase (GMPK). Mounting evidence suggesting roles for PRL3 in oncogenesis and metastasis has catapulted it into prominence as a cancer drug target. Yet, despite significant efforts, there are no PRL3 small molecule inhibitors …

Determination Of The Functional Role Of Rab-Ggt In Physcomitrium Patens., Hyun Jin Jung

Electronic Theses and Dissertations

Protein prenylation, a common lipid post-translational modification, is required for growth and development in eukaryotes. Rab geranylgeranylation involves the addition of one or two 20-carbon geranylgeranyl moieties to Rab-GTPase target proteins, which regulate intracellular vesicle trafficking. The reaction is carried out by heterodimeric Rab geranylgeranyltransferase (Rab-GGT), which is composed of two associated α- and β-subunits, with the assistance of an additional protein called Rab escort protein (REP). Loss of function of the Rab-GGT α subunit RGTA1 has not been reported in any plant. While knockout of either of the two β subunits RGTB1 or RGTB2 results in …

Regulation Of Systemic And Cellular Metabolism In Prostate Cancer By Camkk2 And Elucidation Of Atgl’S Role In Disease Progression, Dominik Awad

Dissertations and Theses (Open Access)

The androgen receptor (AR) is the major driver of prostate cancer; hence, men with progressing disease are treated with androgen deprivation therapy (ADT). However, the majority of patients will relapse within 2-3 years due to multiple AR reactivation mechanisms. Thus, AR and the processes downstream of the receptor remain central drivers of prostate cancer. A direct target of AR is CAMKK2, a gene coding for the serine/threonine kinase Ca^2+/calmodulin-dependent protein kinase kinase 2 (CAMKK2), a protein upregulated in advanced prostate cancer. CAMKK2 modulates many of its pathological effects through the phosphorylation and activation of the 5' AMP-activated …

Grk3 Connects Angiogenesis And Neuroendocrine Differentiation In Prostate Cancer By Activating Hdac2 That Epigenetically Represses Tsp1 And Rest, Samira Naderinezhad

Dissertations and Theses (Open Access)

Prostate cancer (PCa) is the second most frequent cancer and the second leading cause of mortality in men in the United States. Neuroendocrine prostate cancer (NEPC) is the aggressive subset of castration-resistant prostate cancer (CRPC), found in ~20% lethal CRPC. The mechanisms underlying the progression of PCa to NEPC are still largely unclear, and new drug targets are desperately needed. NEPC is highly vascularized (angiogenic) and characterized by high expression of neuroendocrine markers. However, direct molecular links connecting angiogenesis and neuroendocrine differentiation are elusive.

Since epigenetic regulation has been implicated in NEPC progression, we examined expression patterns of 147 epigenetic …

The Role Of The Hypoxia-Inducible Factor 2 In Pancreatic Cancer: Mechanisms Of Tumor Immunosuppression And Intestinal Radioprotection, Carolina Garcia Garcia

Dissertations and Theses (Open Access)

Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease with dismal prognosis. The only curative option for patients is surgery, but over 80% of patients are not surgical candidates. Unfortunately, PDAC is resistant to the three remaining options. PDAC is characterized by a profoundly hypoxic and immunosuppressive stroma, which contributes to its therapeutic recalcitrance. Alpha-smooth muscle actin+ (αSMA+) cancer-associated fibroblasts (CAFs) are the most abundant stromal component, as well as mediators of stromal deposition. The hypoxia-inducible factors (HIF1 and HIF2) coordinate responses to hypoxia, yet, despite their known association to poor patient outcomes, their functions within the PDAC tumor microenvironment (TME) …

Investigating The Biochemical Properties Of A Novel Mutation, A194v, In Human Rad51, Briana Vollbeer

All Theses

DNA double-strand breaks (DSB) are one of the most serious DNA lesions because improper repair of a DSB can lead to loss of heterozygosity, aneuploidy, and cancer. One of the primary pathways to repair DSBs is homologous recombination (HR). HR resects the DNA around the DSB and then uses homologous DNA as a template to restore the broken sequence. RAD51 has a vital function in this pathway by forming a nucleoprotein filament on a resected end of the DSB. The nucleoprotein filament searches for homology within the homologous DNA. Once homology is located, strand invasion followed by strand exchange occurs. …

Modeling Electrostatics In Molecular Biology And Its Relevance With Molecular Mechanisms Of Diseases, Mahesh Koirala

All Dissertations

Electrostatics plays an essential role in molecular biology. Modeling electrostatics in molecular biology is complicated due to the water phase, mobile ions, and irregularly shaped inhomogeneous biological macromolecules. This dissertation presents the popular DelPhi package that solves PBE and delivers the electrostatic potential distribution of biomolecules. We used the newly developed DelPhiForce steered Molecular Dynamics (DFMD) approach to model the binding of barstar to barnase and demonstrated that the first-principles method could also model the binding. This dissertation also reflects the use of existing computational approaches to model the effects of Single Amino Acid Variations (SAVs) to reveal molecular mechanisms …

Heat Stress Response And Excystation In Entamoeba Histolytica, Irem Bastuzel

All Dissertations

Entamoeba histolytica is a water- and food-borne intestinal protozoan parasite that causes amoebiasis and liver abscess and is responsible for symptomatic disease in approximately 100 million people each year leading to ~ 100,000 deaths. The most common disease transmission follows the oral-fecal route, but it can also be transmitted by mechanical vectors such as animals carrying the amoeba from contaminated sources to water systems. In rare cases, disease transmission has been recorded in some patients in which men-to-men sexual practices were preferred.

The life cycle of E. histolytica starts through ingestion of infectious cysts, which are non-dividing, quadri-nucleated structures surrounded …

Identification Of Genomic, Proteomic, And Metabolomic Signatures Associated With Pulmonary Hypertension Syndrome In Broilers, Duaa Almansaf

Graduate Theses and Dissertations

The present dissertation contains a collection of studies that examine the genomic, proteomic, and metabolomic association to pulmonary hypertension or ascites phenotype in fast-growing broilers. Pulmonary hypertension is a multifactorial metabolic disease influenced by physiological, environmental, and nutritional factors. It is characterized by a number of structural changes including, thrombosis and adverse pulmonary vascular remodeling. Thus, the atrial pressure is increased, and the right ventricle becomes hypertrophied, resulting in heart failure and the death of the bird. Pulmonary hypertension or ascites is a global problem that has negatively impacted the economy. The increased mortality rate of broilers (25%) is estimated …