Molecular Genetics Commons^™

Exploring Competitive Dynamics Between Pseudomonas Baetica And Salmonella In A Polymicrobial System, Braxton E.M. Stout

Electronic Theses and Dissertations

The global rise in antimicrobial resistance has catalyzed a greater focus on polymicrobial research aimed at characterizing microbial interactions and uncovering new therapeutic strategies. Though it has long been of interest, environmental soil-derived bacteria remain largely under-represented in research and thus uncharacterized in this field. This project aimed to identify soil microbes that display inhibitory mechanisms to potential nosocomial pathogens. Soil sample S1S3-2 displayed inhibitory phenotypes toward numerous bacteria and was identified as Pseudomonas baetica. In both planktonic and biofilm growth, P. baetica was able to inhibit Salmonella arizonae through a contact-dependent and temperature-dependent manner. Screening of a transposon insertion …

Data Curation And Integration For Cancer Cell Line Pharmacogenomics Analysis, Meric Kinali

Graduate Masters Theses

Cancer cell lines are essential resources for connecting genomic and molecular features with drug response and identifying biomarkers. Therefore, large-scale cancer cell line resources have been growing, but this introduces challenges such as data standardization, consistent annotation, matching identifiers, cross-database integration, and a reproducible computational framework. CellMiner Cross Database (CellMinerCDB) integrates pharmacogenomic datasets from multiple resources and provides a standardized analysis of cell lines across datasets. This thesis examines cancer cell line cross-databases and their importance in pharmacogenomics, with a particular focus on CellMinerCDB. As part of this work, I developed an R package for the gCSI (Genentech Cell Line …

Validating The Expression Of Genes Potentially Involved In The Development Of Aggressive Melanoma Tumor In The Zebrafish Melanoma Model, Mayra Matos Diaz

Theses, Dissertations and Culminating Projects

Melanoma is an aggressive form of skin cancer characterized by rapid progression, metastatic potential, and the frequent development of resistance to targeted therapies. Although the Inducible cAMP Early Repressor (ICER) has been identified as a potential tumor suppressor in melanoma, the molecular mechanisms underlying its role in tumor progression remain poorly understood. Building upon the transcriptomic findings of Wheelan et al. (2025), this study investigates the relationship between ICER and ten candidate genes (gdf6a, pdgfra, col4a4, fgfr2, pdgfrb, cdkn1a, fgf5, akt1, met, and notch3) associated with BMP signaling. Quantitative polymerase chain reaction (qPCR) was used to compare gene expression between …

A Genetic Analysis Of The Rare Endemic Astragalus Ripleyi Barneby, Juan Antonio Jaramillo-Chico

Master's Theses

Astragalus ripleyi Barneby is a rare endemic species found in the San Luis Valley of the southern portions of the Rocky Mountains in Colorado and New Mexico. Though not federally listed as endangered, the species is on the Bureau of Land Management’s Sensitive Species List, warranting protection and continued management. This study aims to provide information about the genetic health of the species to inform conservation efforts and provide updated management recommendations. A genetic health analysis was conducted investigating the levels of diversity present in the species, how genetic diversity is structured across the known range of the species and …

Computational Insights Into Nucleosome Dynamics In Epigenetics Using Molecular Dynamics Simulations, Rutika Patel

Dissertations, Theses, and Capstone Projects

Nucleosome core particles (NCP) are the building blocks that form a highly organized and compact chromatin structure. Nucleosomes package DNA in the nucleus of eukaryotic cells. The NCP consists of about 147 base pairs of DNA wrapped around the histone octamer, with 1.65 superhelical turns in a left-handed manner. The histone octamer is composed of two copies of H3, H4, H2A, and H2B. Together with histone H1 and linker DNA, they further assemble into a higher-order chromatin structure. The nucleosome complex is stabilized by electrostatic interactions between positively charged histone residues and the negatively charged DNA backbone. To effectively access …

Investigating Cryptic Diversity In The Hawaiian Endemic Plant, Psychotria Mariniana (Rubiaceae), Uyen Thi Hoang Nguyen

Master's Theses

Islands, with their isolation and steep environmental gradients, serve as natural laboratories for studying speciation. Molecular phylogenetic and population genetic methods utilizing Next-Generation Sequencing (NGS) have revolutionized our ability to document patterns of genetic divergence and diversity. Cryptic diversity, genetically distinct populations that were previously unrecognized as unique, and cryptic speciation, where divergent genetic populations may be deserving of status as unique species, have been observed in many taxa. The Hawaiian Islands provide an ideal setting for studying divergence and speciation due to their extreme isolation, known ages, and volcanic origin. Previous work has investigated the evolutionary relationships of the …

Exploring Biogeographical Ancestry Inference Of New York Residents Using A 45 Indel Panel, Amanda Martinez

Student Theses

Biogeographical ancestry (BGA) inference is an important tool in forensic science, providing supplemental information when comparison/reference DNA is not available for traditional DNA analyses. Insertion/deletion polymorphisms (INDELs) have been used in the last decade as ancestry-informative markers (AIMs) for BGA inference because they can be easily adapted to forensic-type samples and are determined using low cost and easy processing methods. Limited research has attempted to estimate ancestry and admixture in United States (U.S.) populations. This study evaluated the effectiveness of a 45- and 21- INDEL panel to measure population admixture proportions of four different origins (African, European, East Asian and …

Environmental Dna (Edna) Assessment Of Fish And Decapod Diversity And Their Association With Cetacean Distribution In Matang Coastal Waters, Perak, Lim Chuan Hui

Student Works (2020-2029)

The estuarine and coastal regions of Matang, Perak, Peninsular Malaysia, are vital fishing grounds and recognised biodiversity hotspots, but are increasingly exposed to human activities. Understanding the biodiversity of marine fish and decapods is crucial for effective conservation efforts. Conventional biodiversity monitoring methods face several challenges, including invasiveness, inconsistencies in sampling techniques, reduced taxonomic accuracy, time-consuming processes, high costs, and often only providing approximate estimates. In this study, we evaluated the use of environmental DNA (eDNA) metabarcoding to assess marine fish and decapod diversity in Matang waters and to explore possible associations between fish assemblages and local cetacean occurrence. Water …

An Investigation Of Entamoeba Histolytica Chitin Synthases And Other Encystation Factors In Early Encystation, John N. Talledo

All Theses

Entamoeba histolytica is a food-and-water-borne human protozoan pathogen that relies on a two-stage life cycle for successful proliferation outside of the host. E. histolytica exists in its dormant cyst form while outside of its host and converts to the motile trophozoite (amoeba) form in the small intestine. The trophozoites colonize the large intestine to cause symptomatic disease in ~10% of infections, resulting in ~100 million cases of amoebic dysentery each year. Trophozoites can convert back to the cyst form, which is shed in feces to continue the infection cycle.

Currently, there is a lack of understanding of the exact molecular …

Investigating The Taxonomic Uncertainties Of Potentilla Rupincola, Natalie Elizabeth Hieber

Master's Theses

Landscape stewardship is an integral role for land managers that becomes more important when rare or endangered species occur within managed areas. Conservation across the landscape is a primary concern for land managers, but resources allocated for conservation can be limited due to many competing goals. Taxonomic uncertainty surrounding rare and endangered taxa, particularly plant taxa, that have historically been classified solely using morphological features further complicates conservation planning. One such taxon is Potentilla rupincola, a rare plant endemic to the eastern Rocky Mountains in Colorado. For over a century, botanists have debated whether P. rupincola is a distinct species …

Genetic Screen For Regulators Of Pol4, A Dna Repair Polymerase In Saccharomyces Cerevisiae, Pasang Dolma Sherpa

Theses and Dissertations

In Saccharomyces cerevisiae, DNA polymerase 4 (POL4) is the beta repair polymerase, the product of the POL4 gene, and is involved in base excision repair (BER) and microhomology-mediated end joining (MMEJ). Despite its involvement in these repair pathways and its conservation across eukaryotes, deletion of POL4 shows no detectable phenotype under standard laboratory conditions. I hypothesized that unknown genes act as backup systems, providing redundant activities that allow pol4Δ cells to survive. To test this, a genetic screen for mutants showing synthetic lethality with pol4Δ was implemented. I constructed a strain lacking the POL4 gene and carrying …

The Hitchhiker's Guide To The Host: Fleas And The History Of Pikas In North America, Josh Pletcher

All NMU Master's Theses

Parasite phylogenetics can offer windows into the cryptic evolutionary history of hosts, often highlighting events that are not recorded by the phylogenetics of the host. Pikas (small lagomorphs) host a diverse parasite community comprising endoparasites (e.g., coccidians, nematodes, and cestodes) and ectoparasites (e.g., fleas and mites). Phylogenetic analysis of pika endoparasites has revealed pikas evolved in Asia and colonized North America in two waves, and that contact between these two pika lineages allowed parasites to be transferred from one lineage to another and to survive the extinction of their original host. To uncover these cryptic histories, understanding the biogeography of …

Characterizing The Molecular Response Of Embryonic Zebra Finch To Acute Sound Playback, Saidat O. Adeniran-Obey Miss

All Theses

Auditory stimuli are important cues that influence developmental plasticity in animals and are important for development and adaptation to an ever-changing environment. In the zebra finch (Taeniopygia guttata), there is evidence of adaptive developmental reprogramming in response to a prenatal ‘heat call’. Embryos exposed to this heat call exhibit changes in growth rate post-hatch, increased heat resistance, and enhanced reproductive success at maturity. However, it has long been assumed that embryonic zebra finches cannot respond to sound due to the immaturity of their auditory system. These findings raise the critical question of whether late-stage zebra finch embryos can, …

Using The Flexon Approach To Rnai To Identify Essential Genes That Affect Gonadal Development In C. Elegans, Joyce S. Lefevers

Undergraduate Theses

To elucidate the molecular role of essential genes in the gonadal development of Caenorhabditis elegans (C. elegans) it is necessary to utilize specialized molecular techniques such that the phenotypic effects of gene knockdown can be studied while the viability of the organism is preserved. Shaffer and Greenwald (2022) developed the floxed exon (flexon), a tool that improves upon previous approaches to spatiotemporal control of gene expression. The flexon subunit is made up of an artificial exon with a stop cassette flanked by artificial introns which, when inserted into a gene of interest, prevents the expression of that gene. …

Quantification Of Mouse Tracheal Epithelial Cell Differentiation With Cilia Defects, Olivia V. Allen

Honors Thesis

Primary Ciliary Dyskinesia (PCD) is an autosomal recessive disorder that affects 1 in every 7,500 live births. PCD results from motile cilia defects, impairing mucociliary clearance and causing chronic respiratory infections. Our lab studies include three PCD mouse lines — bgh (Spef2), nm1054 (Cfap221), and Cfap54^gt/gt (Cfap54). Prior transcriptomic data led us to hypothesize that PCD mutant mouse tracheal epithelial cells (MTECs) exhibit reduced differentiation into ciliated cells. MTECs from the trachea of the Wild Type (WT) and the PCD mutant mouse lines were cultured at an Air Liquid Interface (ALI) to start …

Metagenomic Profiling Of Gut Microbiome Signatures Across Liver Disease Stages And Hcv-Related Hepatocellular Carcinoma In Egyptian Patients, Marwa A. Zahra

Theses and Dissertations

Dysbiosis in the gut microbiome, particularly concerning the synchronous crosstalk between the gut and the liver, has been associated with various diseases. This study profiles the gut microbiome in liver diseases among Egyptian patients, with a focus on the hepatitis C virus (HCV) and hepatocellular carcinoma (HCC), both of which are highly prevalent in Egypt. Utilizing shotgun metagenomic sequencing, we analyzed microbial gene catalogs and taxonomic profiles from 46 Egyptian patients categorized into five groups: healthy individuals, liver disease patients of different etiologies, post-HCV, treated HCV, and HCV-HCC patients. Healthy and treated HCV patients exhibited distinct microbial profiles characterized by …

A Trajectory Of Zostera Marina (Eelgrass) Ecosystem Recovery: Pre- And Post-Hurricane Sandy Degradation In Barnegat Bay, New Jersey, Edgar A. Medina

Theses, Dissertations and Culminating Projects

Hurricane Sandy struck Barnegat Bay, New Jersey in 2012 and obliterated the benthic marine ecosystem with extensive damage to Zostera marina meadows. Previous genetic assessments of Barnegat Bay Z. marina in 2008 revealed low heterozygosity and low connectivity between populations. The great disruption caused by Hurricane Sandy motivated us to investigate the long-term effects of the storm on the genetic condition of the eelgrass populations in the year 2021. The investigation revealed improvements in heterozygosity, inbreeding, and connectivity. These findings drove us to investigate the genetics of Barnegat Bay eelgrass populations in the intervening years of 2013 and 2017 with …

A Framework For Characterizing The Peripheral Immune Isonome Using Long-Read Single-Cell Rna Sequencing And Its Relevance To Neurological Disease, Patricia Hayes Doyle

Theses and Dissertations--Neuroscience

Long-read single-cell RNA sequencing provides an opportunity to understand human health and disease at isoform resolution, revealing cellular diversity and disease mechanisms difficult to resolve with bulk or short-read methodologies.

Using a modified PIPseq workflow and computational pipeline adapted for Oxford Nanopore (ONT) sequencing, we profiled isoform usage across immune cells, integrating marker expression and isoform discovery, generating the largest long-read single-cell dataset of human immune cells from a single individual to date. We identified non-canonical protein-coding variants of GZMB and CD3G enriched in unexpected cell types. We also discovered novel transcripts from CMC1 and LYAR with cell-type-specific signatures that …

Fluorescent Protein Imaging Approaches Uncover Dynamic Subcellular Distribution Of Core Clock Proteins In Neurospora Crassa, Ziyan Wang

Dartmouth College Ph.D Dissertations

Circadian clocks are endogenous self-sustained timekeeping systems that allow organisms to anticipate and adapt to daily environmental cycles. Found in diverse forms of life, these molecular clocks regulate the expression of ~ 40% of the genome in animals, fungi, and plants. In animals and fungi, circadian oscillators are built on transcription-translation feedback loops (TTFLs), in which positive regulators drive the expression of negative regulators which, once synthesized and imported into the nucleus, inhibit their own activators. This precisely regulated negative feedback incorporates multiple steps of delays that are essential for generating ~24-hour rhythms. Through these mechanisms, circadian clocks temporally coordinate …

Phylogeography, Fungal Host Specificity, And Fitness In The Corallorhiza Maculata Species Complex, Hana Thixton-Nolan

Graduate Theses, Dissertations, and Problem Reports (ETD)

Mycoheterotrophic plants exploit fungi for most or all nutritional needs, providing a compelling system to address the evolutionary consequences of genome reduction, population-level variation, and germination requirements. I am using the widespread Corallorhiza maculata species complex to address questions of genomic variation, fungal host specificity, morphological variation, and germination requirements across the broad geographic range from Mexico to northern North America. This complex contains C. bulbosa, C. macrantha, and C. mertensiana, the latter with three varieties (maculata, occidentalis, and mexicana). These taxa vary in flowering time, floral morphology, and fungal associations. However, the degree …

Building A Cell Specific System For In Vivo Rna Imaging Of The Endogenous Actin Gene In C. Elegans, Jasmine A. Huerta Canete

Theses and Dissertations

Messenger RNA (mRNA) plays a crucial role in protein synthesis and cellular processes, important for the development of cells such as neurons. When dysregulation occurs, it can lead to outcomes such as aberrant translation, causing neurodegenerative conditions to arise. Unfortunately, the localization of mRNA in an in vivo cell specific manner is still not understood. To address this, we decided to develop a cell-specific system to image RNA in vivo, within the organism known as C. elegans with a focus on the actin gene. The Actin gene encodes for an important cytoskeleton protein expressed ubiquitously, vital for the cell …

Overview And Methods Of Molecular Paleontology: A Review, Shelby Touchstone

Williams Honors College, Honors Research Projects

Molecular paleontology—the study of ancient biomolecules preserved in fossils and sediments, including ancient DNA, lipids, and proteins—has motivated researchers since the 1950s, inspiring both scientific inquiry and broader cultural imagination. Think Jurassic Park. This honors thesis presents a comprehensive review of the history, current state, and methods of the field of molecular paleontology. Drawing on peer-reviewed literature and scholarly resources accessed through databases such as EBSCO and Bierce library, this review examines key techniques such as Next Generation Sequencing and amino acid racemization and will go over limitations and controversies in the field. It will also explore potential new …

Assessing The Impact Of Storing Water Samples At Ambient Temperature On Plankton Metabarcoding, Stephanie N. Lievano

Honors Undergraduate Theses

Increasing incidence of Harmful Algal Blooms (HABs) has led to fish kills, air quality hazards, and economic impacts. One economic impact is on tourism, one of the main sources of Florida’s income, where billions of dollars are lost to such events. The Florida Fish and Wildlife Conservation Commission Fish and Wildlife Research Institute (FWC-FWRI), with the help of collaborators, collects water samples from across the state for HAB monitoring. These samples are stored at ambient temperature for up to 24 hours which could directly affect data analyses. Here, in collaboration with FWRI-FWC, I investigated whether this storage technique affects plankton …

Coordinating The Layers: Regulation Of Peptidoglycan Synthesis And Cell Wall Assembly In Mycobacterium Smegmatis By Murj And Pgfa, Karen Emmanuella Samaga-De-Tembiwa

Biology Dissertations

The mycobacterial cell envelope consists of three covalently linked layers whose synthesis must be coordinated to maintain structural integrity during polar growth. While the biosynthetic enzymes for each layer are well characterized, the molecular mechanisms that coordinate synthesis across layers have remained poorly understood. This thesis investigates two essential transmembrane proteins, PgfA and MurJ, that regulate peptidoglycan metabolism in Mycobacterium smegmatis and provide new insight into how mycobacteria synchronize cell wall assembly.

We present evidence that PgfA functions as a bifunctional regulator that links peptidoglycan metabolism to the availability of trehalose monomycolate (TMM), a key mycolic acid precursor. Through epistasis …

Bio-Orthogonal Chemistry-Based Strategy To Turn-On And Turn-Off Crispr-Cas9 Gene Editing In Solution And In Live Cells, Bhoomika Pandit

Electronic Theses & Dissertations (2024 - present)

The CRISPR–Cas9 system is a widely popular tool for genome engineering. There is a strong interest in developing tools for temporal control of CRISPR-Cas9 activity to address some of the challenges and to broaden the scope of potential applications. In this thesis I describe two biorthogonal based approaches to either Turn-ON and Turn-OFF CRISPR-Cas9 gene editing.

In first project work I describe a bio-orthogonal chemistry-based approach to Turn-ON Cas9 nuclease activity with temporal precision. We report a TCO-acylimidazole reagent that acylates 2′-OH groups of RNA. Poly-acylation (“cloaking”) of RNA was optimized in vitro using a model 18-nt oligonucleotide, as well …

Cytonuclear Incompatibilities In Hybrid Systems: Oxidative Phosphorylation Capacity And Nuclear Marker Transmission Ratio Distortion In Hybrids Of An Introgressed Strain Of Parasitoid Wasp, Julie Kessler

College of Graduate Studies: Theses & Dissertations

Speciation is an evolutionary process resulting in the divergence of populations into reproductively isolated species, a key concept that supplies our planet with an abundance of biodiversity. Mechanisms for speciation center on obstacles to fertilization and include post-zygotic barriers, such as intrinsic deleterious interactions, that arise in hybrid systems where genetic variants are combined. Genes from separate parent lineages are often incompatible due to the co-evolution of paired genes within a singular species not matching their complement genes in another species, and the result is a reduction in fitness of the hybrid when these genes come together. The mitochondrial OXPHOS …

Regulation Of Chromatin Remodeling By The Post-Hsa Domain Of Brg1, A Subunit The Baf Atp-Dependent Chromatin Remodeling Complex, Min Sze Ewe

Theses & Dissertations

The ATP-dependent chromatin remodeler BAF complex regulates nucleosome positioning, chromatin accessibility, and tissue specific gene expression. Its catalytic subunit, BRG1, contains several regulatory domains including the post-HSA region, proposed to modulate ATPase activity. Multiple cancer-associated mutations map to these regulatory regions underscoring their importance, yet the precise role of the post-HSA region in chromatin remodeling remains poorly understood.

To investigate the function of the post-HSA domain, we ectopically expressed FLAG-tagged BRG1 with post-HSA deletion (Δpost-HSA BRG1) in mouse embryonic stem cells. Western blot analysis confirmed expression of the mutant protein. To determine the effects of mutant protein expression on chromatin …

Mechanistic Insight Of Neuropilin-2 Expression During The Progression Of Prostate Cancer, Sanika Bodas

Theses & Dissertations

Advanced prostate cancer represents a particularly aggressive and challenging form of prostate cancer (PCa) that shows resistance to both traditional therapies, such as androgen deprivation therapy, and newer treatment modalities like hormone therapies and immunotherapies. For patients diagnosed with advanced stages of PCa, treatment options are limited, and chemotherapy is often the last line of defense. Unfortunately, chemotherapy can severely diminish the quality of life, particularly in older patients, due to its harsh side effects, including fatigue, immune suppression, and overall physical decline. Despite these challenges, researchers and clinicians remain focused on developing more effective and targeted treatments for patients …

Generating Predictive Gene Expression Signatures For Alzheimer's Disease Using Postmortem Brain Tissue, Ashley Duche

Pharmaceutical Sciences (PhD) Dissertations

Background: Alzheimer’s Disease (AD) is a progressive neurodegenerative disorder characterized by the accumulation of amyloid-beta (Aβ) plaques and tau protein aggregates. These pathological features develop in specific brain regions, but why some areas are more vulnerable to early AD-related changes remains unclear. To address this, predictive gene expression signatures were developed to explore the molecular mechanisms underlying regional susceptibility to AD pathology.

Methods: This was performed using postmortem brain (PMB) tissue from participants in the Religious Orders Study and Memory and Aging Project (ROSMAP), Mayo Clinic, and Mount Sinai Brain Bank (MSBB) to generate gene expression signatures from six brain …

Structure And Function Studies On Trna Splicing Endonuclease, Justin G. Underwood

Dissertations and Theses (Open Access)

A subset of eukaryotic pre-tRNAs have introns that must be spliced out to become mature molecules capable of functioning in translation. This essential processing step is performed by tRNA splicing endonuclease (TSEN), a highly conserved heterotetramer with two catalytic and two structural subunits. In addition to this conserved function, archaeal TSEN also processes pre-rRNA and yeast TSEN cleaves some mRNAs that encode mitochondrial proteins to initiate mRNA degradation. Interestingly, single amino acid mutations in TSEN cause the human Mendelian disease pontocerebellar hypoplasia (PCH) by an unknown mechanism. Recently, several groups have determined the structure of human TSEN, revealing similarities and …