Biochemistry, Biophysics, and Structural Biology Commons^™

Characterizing The Role Of Pa5189 Of Pseudomonas Aeruginosa In Deletion And Overexpression Mutants, Seh Na Mellick

Theses/Capstones/Creative Projects

In the context of rising multidrug resistance in biofilm-forming pathogens like Pseudomonas aeruginosa, this study investigates the role of the understudied transcription factor PA5189 in antibiotic resistance and biofilm formation. PA5189 deletion and overexpression mutants were created in a parent P. aeruginosa strain using pEX18Tc-based recombinant suicide vectors, with genotypic verification of putative triparental conjugants achieved through restriction digestion and PCR. The study revealed that PA5189 overexpression significantly increases resistance to commonly used broad spectrum antibiotics such as ciprofloxacin and imipenem. Additionally, differential expression of PA5189 was found to notably affect biofilm formation, with variations contingent on the nutrient …

Predicting The Identities Of Su(Met-2) And Met-3 In Neurospora Crassa By Genome Resequencing, Kevin Mccluskey, Daren Brown, Erin Bredeweg, Scott E. Baker

Fungal Genetics Reports

A significant number of classical genetic Neurospora crassa biochemical mutants remain anonymous, unassociated with a physical genome locus. By utilizing short read next-generation sequencing methods, it is possible to sequence the genomes of mutant strains rapidly and economically for the purpose of identifying genes associated with mutant phenotypes. We have taken this approach to connect genes and mutations to “methionineless” phenotypes in N. crassa.

Alopecia As An Early Clinical Marker For Azathioprine Induced Myelosuppression: A Case Report, Nilanjana Dutta , Final Year Mbbs, Dr. M Suresh Babu , Professor, Dr. Subramanian Ramaswamy , Professor, Dr. Mahabaleshwar Mamadapur , Assistant Professor

Digital Journal of Clinical Medicine

Azathioprine is a pro-drug and is metabolized by the TPMT enzyme in the body. In South Asians, Azathioprine is known to cause alopecia and bone marrow suppression in patients with TPMT enzyme deficiency. In India, the prevalence of TPMT mutation varies from 1.2- 10%. A new mutation was detected in 2014, NUDT15 whose incidence varies from 8.5-16%. Patients with mutation in both TPMT and NUDT15 develop myelosuppression faster. In our case, alopecia manifested as the first clinical feature of Azathioprine myelosuppression. Physicians need to recognize early clinical clues (alopecia) to avoid the impending development of myelosuppression and to look for …

Chemical Synthesis Of Sensitive Dna, Komal Chillar

Dissertations, Master's Theses and Master's Reports

Over the past decades, researchers have tried various chemical methods to synthesize modified oligodeoxynucleotides (ODNs, i.e. short segments of DNAs). Traditional ODN synthesis methods require strong basic, and nucleophilic conditions for the deprotection and cleavage of the ODN from the solid support. However, the sensitive ODNs containing labile functionalities are vulnerable to such harsh conditions. Sensitive ODNs have a wide range of applications in research and pharmaceuticals. To synthesize sensitive ODNs, researchers devised different strategies but no practical methods have been developed. To overcome these challenges, we developed alkyl Dim alkyl Dmoc technology. This innovative technology uses weakly basic and …

Characterization Of Lignin Structural Variability And The Associated Application In Genome Wide Association Studies, Nathan D. Bryant

Doctoral Dissertations

Poplar (Populus sp.) is a promising biofuel feedstock due to advantageous features such as fast growth, the ability to grow on marginal land, and relatively low lignin content. However, there is tremendous variability associated with the composition of biomass. Understanding this variability, especially in lignin, is crucial to developing and implementing financially viable, integrated biorefineries. Although lignin is typically described as being comprised of three primary monolignols (syringyl, guaiacyl, p-hydroxyphenyl), it is a highly irregular biopolymer that can incorporate non-canonical monolignols. It is also connected by a variety of interunit linkages, adding to its complexity. Secondary cell wall …

Effect Of Plant Genotype On Plant-Microbe Interactions And Multi-Generation Ecosystem Selection Of Microbial Communities Associated With Plant Biomass In Arabidopsis Thaliana, Nachiket Shankar

Graduate Doctoral Dissertations

The microbiome's role in shaping host phenotypes is a critical area of investigation, with implications for ecology, evolution, and host health. Dynamic plant-microbe interactions are influenced by factors like soil type, environment, and genotype. Understanding their impact on microbial communities is key for tailored plant benefits. An artificial ecosystem selection experiment was done for eight generations with Arabidopsis thaliana Ler and Cvi. This revealed distinct microbial communities shaped by genotypes and biomass treatments. Initially, environment dominated, but over time, genotype and biomass gained influence, explaining ~40% of the variation. Moreover, genotype-specific rhizobacterial associations were observed, enhancing understanding of community dynamics …

Upland Cotton And Nematodes: An Analysis Of Historical Resistance, Upcoming Threats, And Co-Inoculation Effects, Amanda Gaudin

Theses and Dissertations

Upland cotton (Gossypium hirsutum ) is an important fiber crop grown throughout the southern United States. Plant-pathogenic nematodes are worm-like animals that feed on the roots of most agronomic crops, including cotton. The southern root-knot nematode (Meloidogyne incognita, RKN) and the reniform nematode (Rotylenchulus reniformis, RN) cause significant yield losses in cotton every year. Current sources of resistance are effective but limited, therefore historical screenings of cotton accessions were revisited in search for novel resistance sources. None were identified but many of the screened accessions possessed markers of known root-knot nematode and reniform nematode resistance. …

Utilizing Crispr Cas9 To Visualize Dopamine Receptors In Caenorhabditis Elegans, Lauren Michelle Velasquez

Electronic Theses, Projects, and Dissertations

Dopamine (DA) is a neurotransmitter with imperative implications in many functions including movement, reward, and cognition. Studying the pathways of dopaminergic neurons at multiple levels allows us to understand the ways in which these systems can go wrong. We study dopamine in a model system such as the worm Caenorhabditis elegans because of its relatively simple and well-characterized nervous system. DA is involved in regulating chemosensory behaviors in worms. The purpose of this research project is to definitively answer the following question: Are the dopamine receptors DOP-1 and DOP-4 expressed in chemosensory neurons? Previous reporter assays show that neither of …

Advances In Phaeodactylum Tricornutum Nuclear Engineering, Mark Pampuch

Electronic Thesis and Dissertation Repository

The marine diatom Phaeodactylum tricornutum has the potential to become an excellent platform for the sustainable production of valuable compounds and pharmaceuticals, but currently large-scale engineering of this organism remains a challenge due factors like inefficient genetic transformation protocols and a lack of accurate genomic data. This thesis addresses these two bottlenecks by (i) optimizing an electroporation protocol to P. tricornutum and (ii) remapping genomic data from a scaffolded genome assembly to a telomere-to-telomere genome assembly. An optimized transformation protocol was developed that could consistently transform blunt-ended and DNA with overhangs and yielded up to 1000+ colony forming units per …

Regulation Of The Wnt/Wingless Receptor Lrp6/Arrow By The Deubiquitylating Complex Usp46, Zachary T. Spencer

Dartmouth College Ph.D Dissertations

The evolutionarily conserved Wnt/Wingless signal transduction pathway is critical for the proper development of all animals and implicated in numerous diseases in adulthood. Upon binding of the Wnt/Wingless ligand, a cascade of events culminates in inactivation of the destruction complex, a negative regulator of the pathway, and the subsequent formation of singalosomes which mediate pathway activation. A critical component of signalosome formation is the Wnt/Wingless receptor LRP6/Arrow. Upon canonical pathway activation, LRP6/Arrow undergoes activation via phosphorylation by several kinases and complexes with another Wnt/Wingless receptor Frizzled, along with several cytoplasmic components. While many studies have investigated the regulatory mechanisms of …

A Dna-Peptide Crosslink (Dpc) Increases Mutagenicity In Sos-Induced Escherichia Coli, Alessandra Bassani

Honors Scholar Theses

Bacteria, such as Escherichia coli, have an inducible system in response to DNA damage termed the SOS response. This system is activated when the replicative DNA polymerase (Pol) III encounters a lesion, uncouples from DNA helicase, and single-stranded DNA (ssDNA) accumulates at the replication fork. In this study, we investigated DNA-peptide crosslink (DpC), a common lesion that results from cross-linking of proteins or peptides, UV irradiation, and alkylating agents. To increase survival following formation of a lesion, the SOS response can utilize homologous recombination, translesion synthesis (TLS), or excision repair. With TLS, the levels of DNA Pol II, IV, …

Acetate Metabolism In The Fungal Pathogen Cryptococcus Neoformans, Oly Ahmed

All Dissertations

Cryptococcus neoformans is an environmental basidiomycetous fungus with a worldwide distribution and a wide range of habitats. Inhalation of the desiccated yeasts or spores of C. neoformans often leads to opportunistic pulmonary infections in immunocompromised individuals, and in severe cases causes lethal meningitis following hematogenous dissemination. During infection, depending on the tissue and disease state, the invading fungi experience a range of nutrient microenvironments within the host body. As a result, rapid metabolic adaptations geared towards efficient utilization of carbon sources alternative to glucose become one of the prime determinants of survival and growth for the pathogen. Incidentally, cryptococcal infection …

Gonads Without Glp-1: Silencing Glp-1 In The Male Somatic Gonad In Caenorhabditis Elegans, Matthew Titus

Undergraduate Theses

In C. elegans, the gene glp-1 encodes for a Notch receptor called GLP-1, one of two found in C. elegans’ genome. The gene has been previously implicated in the development of the hermaphroditic germline as well as playing a role in the mitosis/meiosis decision. Genetic screening has further identified it as potentially playing a role in the development of the male somatic gonad, making it an ideal candidate for a reverse genetic. We did this by silencing glp-1 and observing if any alterations to the gonad’s phenotype occur.

Normally this could be done by performing a gene knockout. …

Role Of Cdx4 And Sp5l In Zebrafish Development, Wesley Tsai

Honors Theses

The Caudal Type Homeobox transcription factors cdx are a family of genes found in vertebrates that regulates body regionalization and anterior-posterior patterning. They are also responsible for regulating axial elongation, but the mechanisms behind this behavior are not known. Previous studies in mouse embryonic stem cells have shown that the cdx genes are necessary for upregulating the gene sp5 which may be linked to axial elongation. Sp5 is a zinc-finger transcription factor belonging to the specificity protein (sp) family. Our group has used in-situ hybridization experiments on zebrafish embryos to show that sp5-like (sp5l) is transcribed within tailbud tissues that …

Effects Of Post-Translational Histone Modifications On Transcription Rate, Aaron Bohn

Annual Research Symposium

No abstract provided.

Generation Of Chimeric Rhinoviruses Presenting Sars-Cov-2 Broadly Neutralizing Epitopes And Their Antigenicity Characterization, Danish Ansari

Biotechnology Theses

The global COVID pandemic is not yet fully under control as there were over 21 million new cases of SARS-CoV-2 infections and over 50,000 deaths globally as of January of 2022. A heavily mutated variant of concern, Omicron is responsible for most of these cases which demands an urgency for a new vaccine. NIH reports over 180 vaccine candidates that use various strategies currently in development. However, a recurring concern with these vaccines is that the continuous viral mutations decrease the efficacy of vaccines. Therefore, we proposed to construct a human rhinovirus (HRV) based chimeric virus containing highly conserved, broadly …

Cell Signaling And Stress Response In The Yeast Saccharomyces Cerevisiae: A Study Of Snf1, Scott E. Arbet Ii

Graduate Theses, Dissertations, and Problem Reports

Saccharomyces cerevisiae are yeast that are unicellular eukaryotic organisms that are well studied as a model organism for understanding fundamental cellular processes. The ability of yeast to sense nutrient availability is crucial for their survival, growth, and reproduction. Yeast cells use various mechanisms to sense and respond to nutrient availability, including transporter-mediated uptake, receptor-mediated signaling, and sensing of metabolites. The subcellular localization of nutrient-sensing components is crucial for yeast function in nutrient sensing and signaling. Protein complexes, such as the AMP-activated protein kinase (AMPK) pathway, in nutrient sensing and response, as well as the downstream effects of these pathways …

Dna Methylation And The Response To Infection In Introduced House Sparrows, Melanie Gibson

Electronic Theses and Dissertations

Epigenetics is the study of molecular modification of a genome without changing its base pairs. The most studied type of epigenetic mechanism is DNA methylation, which is capable of turning a gene “on” or “off.” Epigenetic potential is the capacity to which an individual can have methylation on its genome. The more CpGs available, the greater the epigenetic potential. In invasive species, genetic variation has been observed to be paradoxical: not much of it exists on a genomic level, but epigenetically, phenotypic variation can occur. The focus on shift in gene expression in this study is on Toll-Like Receptor 4 …

Dissecting Interactions Across Gene Regulatory Layers In C. Elegans, Morgan Taylor

Biological Sciences Theses and Dissertations

The nematode Caenorhabditis elegans is a powerful tool for studying nervous system genetics. Though relatively simple compared to mammals, C. elegans boasts a remarkably well-conserved neuronal genome and proteome, and its utility in the characterization of neuronal genes has been well-established. However, gene expression is often controlled by complex interactions between multiple genes, and teasing apart the functions of individual genes within such networks remains a challenge. Dissecting these interaction networks is crucial in determining the multifaceted functions of important, conserved regulatory genes. Here we explore interactions between gene regulatory layers in the C. elegans nervous system, employing a synthetic …

The Sos Response In Escherichia Coli K12: An Exploration Of Mutations In Lexa And Reca Using Fluorescence Microscopy, Steven Van Alstine

Doctoral Dissertations

Faithful replication of the genome is paramount for maintaining the fitness of an organism. Therefore, life has evolved inducible mechanisms to be able to repair damaged DNA and maintain evolutionary fitness. The SOS response is a highly conserved DNA damage inducible response that is tightly regulated. Multiple factors contribute to the ability of the cell to perform proper DNA repair and induction of the SOS response including the amount of RecA, mutations in RecA that affect competition for DNA, and other proteins that interact with the RecA filament. The complex relationship between RecA and LexA is the subject of this …

Ngly1 Deficiency Affects Glycosaminoglycan Biosynthesis And Wnt Signaling Pathway In Mice, Amy Batten

PANDION: The Osprey Journal of Research and Ideas

Individuals affected by NGLY1 Deficiency cannot properly deglycosylate and recycle certain proteins. Even though less than 100 people worldwide have been diagnosed with this rare autosomal recessive condition, thousands are affected by similar glycosylation disorders. Common phenotypic manifestations of NGLY1 Deficiency include severe neural and intellectual delay, impaired muscle and liver function, and seizures that may become intractable. Very little is currently known about the various mechanisms through which NGLY1 deficiency affects the body and this has led to a lack of viable treatment options for those afflicted. This experiment uses a loss-of-function (LOF) mouse model of NGLY1 Deficiency homologous …

Towards More Complete Metagenomic Analyses Through Circularized Genomes And Conjugative Elements, Benjamin R. Joris

Electronic Thesis and Dissertation Repository

Advancements in sequencing technologies have revolutionized biological sciences and led to the emergence of a number of fields of research. One such field of research is metagenomics, which is the study of the genomic content of complex communities of bacteria. The goal of this thesis was to contribute computational methodology that can maximize the data generated in these studies and to apply these protocols human and environmental metagenomic samples.

Standard metagenomic analyses include a step for binning of assembled contigs, which has previously been shown to exclude mobile genetic elements, and I demonstrated that this phenomenon extends to all conjugative …

Utilizing Rnai Technology To Develop Novel Agricultural Pesticides, Ethan B. Zand

Undergraduate Student Research Internships Conference

A general description of why RNAi based pesticide technology is a breakthrough technology able to target only pests while not harming others. This presentation gives a summary of RNAi technology, the current drawbacks of conventional pesticides, and our research on how RNAi can be used against the two-spotted spidermite; a polyphagic pest that causes significant financial damage to Canadian and worldwide agriculture

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 …

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

Dissertations & 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) …

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 …

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. …

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 …

Investigating The Biorisk Of Genetically Engineered Thermosynechococcus Elongatus Bp1, Cherrelle Leah Barnes

Chemistry & Biochemistry Theses & Dissertations

Cyanobacteria, also known as blue-green algae, are an ancient group of microorganisms that use simple materials, such as sunlight, carbon dioxide and water, to produce energy while providing oxygen to the atmosphere by performing photosynthesis. Synthetic biology approaches have been employed with cyanobacteria as a platform to produce a range of products, such as biofuels, by inserting a series of genes into the cyanobacterial genome that will allow the conversion of metabolic intermediates to such desired products. Although these methods are promising, it is important to understand any potential bio-risk they pose. This research evaluates the potential bio-risk of genetically …

Defining The Role Of Rare Genetic Variants That Drive Risk And Pathogenesis Of Alzheimer’S Disease, Matthew James Rosene

Arts & Sciences Electronic Theses and Dissertations

Alzheimer’s disease (AD) is the leading cause of dementia and is pathologically defined by the aggregation of extracellular amyloid plaques and intracellular neurofibrillary tangles. Rare heritable mutations within the genes for amyloid precursor protein (APP) and presenilin 1 (PSEN1), and presenilin 2 (PSEN2) cause early onset AD and account for approximately 1% of AD cases. While the majority of AD cases are late-onset (LOAD), which is defined by a markedly more complex genetic architecture that is comprised of many genetic risk factors that influence AD through multiple cellular pathways. The advent of deep sequencing analyses have allowed for the identification …