Biology Commons^™

Genetically Encoded Iron Sensor Cell Line: A Model For Studying Ferroptosis And Cellular Iron Metabolism, Daoud F. Rahman

Theses and Dissertations

Cell death is a biological process that is essential in proper cellular homeostasis, development, and function. Malfunction of this system can lead to different diseases and cancers. Ferroptosis is a form of cell death that occurs as a result of the accumulation of lipid peroxides, that are dependent on intracellular levels of iron. Iron is essential to multiple metabolic processes in the cell, including the catalyzation of lipid peroxides. Thus, intracellular iron levels must be tightly regulated. Our goal is to create a cellular model to study and detect changes in intracellular iron levels. Through the use of a genetically …

Hydroxyurea Globally Inhibits Rna Synthesis, Destabilizes Mrnas, And Triggers Mec1-Opposed Rnapii Accumulation At 3’ Ends Of Genes, Pritpal Kaur

Theses and Dissertations

My dissertation includes two projects. The first project is focused on the regulation of glycolysis and oxidative metabolism by inducing heme synthesis in cancer cells. The second project deals with the effect of hydroxyurea on RNA synthesis. Heme is an essential cofactor for enzymes of the electron transport chain (ETC) and ATP synthesis in mitochondrial oxidative phosphorylation (OXPHOS). Heme also binds to and destabilizes Bach1, a transcription regulator that controls expression of several groups of genes important for glycolysis, ETC, and metastasis of cancer cells. Since many cancers are characterized by a high glycolytic rate regardless of oxygen availability, targeting …

Gating And Pathogenic Mechanism Of Polycystin Ion Channels, Yan Wang

Theses and Dissertations

Autosomal dominant polycystic kidney disease (ADPKD), one of the most common and life-threatening human genetic diseases, is caused by mutations in PKD1 or PKD2 genes. PKD1 gene encodes PKD1 (also known as polycystin-1 or PC1) protein, which are the founding members of the PKD1 proteins family; while PKD2 encodes TRPP2 (also known as polycystin-2 or PC2) protein, the founding member of the TRPP subfamily. PKD1 family consists of PKD1, PKD1L1, PKD1L2, PKD1L3, and PKDREJ. Whereas the TRPP subfamily includes: TRPP2, TRPP3, and TRPP5. Proteins in PKD1 and TRPP families are collectively called polycystins. TRPP proteins can either form homotetrameric ion …

Insight Into Eleutherodactylus Coqui Resilience And Anuran Hypoxia Tolerance Utilizing Pincho, Randy Ortiz

Theses and Dissertations

The onset of high-throughput RNA-sequencing (RNA-seq) technology allowed research into transcriptomics to accelerate exponentially aided by the rapid advancement of bioinformatic pipelines. The Pincho workflow, my first research endeavor, is a transcriptomic workflow developed to create an avenue of high-quality reconstructions from RNA-seq data. High-quality reconstruction standards entail longer transcripts, more complete transcripts, and more raw data utilization. We have discovered an ideal trio of assemblers between transABySS, rnaSPAdes and TransLiG that would best reconstruct next-generation sequencing data according to these standards. We utilized Pincho to drive two distinct experiments: (1) exploring the genetic basis for the successful invasion of …

Interferon Gamma Signaling In Ovarian Cancer Cells, Bijaya Gaire

Theses and Dissertations

Interferon gamma (IFNγ) is a pleiotropic cytokine that can have, depending on the cellular and molecular context, both anti-tumor and pro-tumorigenic functions. IFNγ expression can be induced in cancer cells in response to radiation therapy or immune checkpoint blockade used in cancer treatment. We have previously shown that IFNγ induces expression of the Bcl3 proto-oncogene in ovarian cancer (OC) cells, resulting in their increased proliferation and migration, but the mechanisms are unknown. Here, I demonstrate that the IFNγ-induced Bcl3 expression is dependent on JAK1 and STAT1 signaling, and on p65 NFkB. Furthermore, my data show that the IFNγ-induced Bcl3 expression …

Regulation Of P53 By Trpm6 And Trpm7, Thomas Whitbread

Theses and Dissertations

TRPM6 and TRPM7 are two divalent metal cation channels that also possess a serine/threonine kinase domain. They both play critical roles in cellular and organismal metal homeostasis, and are necessary for proper embryonic development and human health. They may function independently in homomeric units, or act together as heterotetramers that display unique characteristics compared to the homomeric channels. These channel-kinases have increasingly been linked to cancer, displaying altered expression levels in a variety of human cancers and contributing to disease progression. Prior work has shown that TRPM6 and TRPM7 can participate in cancer-related signaling pathways. Here, the potential for TRPM6 …

Dune Building Dynamics Impact Cross-Island Connectivity And Barrier Island Characteristics, Alexander Sabo

Theses and Dissertations

Located at the land-sea interface, barrier islands are important protective features that reduce wave energy and erosion from mainland areas. Further, barrier islands provide habitat for many different organisms and serve as popular areas for recreation and tourism. As sandy landforms, barrier islands are easily disturbed, but often recover after disturbance as a result of island plant communities, specifically dune building grasses. Disturbance on barrier islands is driven by storms, tides, and overwash events. After disturbance has occurred, dune grasses colonize the dunes allowing for dune building and habitat restoration. On the Virginia barrier islands, there are three dominant dune …

Pre-Clinical Trials With Precision-Medicine Based Therapeutics In Basal-Like Patient-Derived Xenografts, David C. Boyd

Theses and Dissertations

Breast cancer treatments have improved over time, but the diseases seeing the most benefit from these improvements have the estrogen receptor, progesterone receptor, or are positive for HER2. Basal-like breast cancer tends to not have these biomarkers, which necessitates their treatment to be traditional, untargeted therapeutics which are less effective and tend to have harsh adverse effect profiles – this is an important unmet need. These studies utilize a variety of techniques, including tissue culture, viability assays, high-throughput screening, in vivo drug treatments and imaging, pathway analyses, molecular techniques such as Western blot, antibody arrays, RNA sequencing, sc RNA sequencing, …

Plant Trait Effects On Tidal Wetland Methane Emission, Adam M. Dunn

Theses and Dissertations

High rates of carbon (C) sequestration exhibited by coastal wetlands is an important natural climate solution to global environmental change. At the same time, however, wetlands are the largest natural source of methane (CH₄) to Earth’s atmosphere, a potent greenhouse gas that influences the global climate. Wetland CH₄ emissions display high degrees of uncertainty in accounting for spatial and temporal variations in emissions due to the complex interactions between biotic and abiotic factors that influence methane production and transport, in addition to simultaneous influences from climate-driven effects on wetlands such as rapid sea level rise and increased …

Epithelial Membrane Protein 3 (Emp3b) Is A Novel Regulator Of Sympathetic Nervous System Development In Zebrafish., Jessica M. White

Theses and Dissertations

Notable progress has been made in understanding the development of the neural crest (NC). Neural crest cells (NCCs) can be divided into 4-5 subpopulations. A major lineage among trunk NC derivatives are sympathoadrenal (SA) cells, which give rise to the sympathetic nervous system (SNS). Trunk NCCs follow a ventromedial migration pathway where signals derived from the dorsal aorta instruct migrating NCCs to a SA cell fate. Defects in NC development can result in syndromes known as neurocristopathies. Neuroblastoma is one of the most common forms of pediatric cancer affecting nearly 800 infants each year in the United States (Takita et …

Salinization Impacts On Heterotrophic Respiration, Ecosystem Respiration, And Plant Productivity In Tidal Freshwater Marshes, Kelsie J. Moses

Theses and Dissertations

Tidal freshwater marshes have preserved substantial stocks of soil carbon, which represents carbon dioxide that is no longer in the atmosphere. There is conflicting evidence in the literature about how disturbances such as sea level rise and associated wetland salinization impact the accumulation and long-term stability of this stored carbon. The goal of this experiment was to quantify how salinization impacts total ecosystem respiration and its component parts, autotrophic and heterotrophic respiration. This was a microcosm experiment using a C4 plant (Spartina cynosuroides) grown in soil derived from C3 plant matter and exposed to different salinities (0 to …

Evaluation Of Novel Litter Amendments For Use In The Commercial Broiler Industry, Jorge A. Urrutia

Theses and Dissertations

Poultry litter amendments (LA) are commonly used to maintain good litter quality; the most common ones; are acidifiers. However, concern over the lifespan of LA acidifiers (d) and corrosive nature revealed a need for alternative LA. Products of interest include biochar (BC), superabsorbent polymers (SAPs), and alum mud (AM). Experiment 1 was a screening study (n=17 treatments, no birds) conducted to determine the optimal application rate/method of BC, SAPs, and AM vs.commercial LA and a control. Most SAPs treatments measured metrics may be similar (i.e., bacteria, water activity) or better (pH) vs. commercial LA (PLT). High inclusions of novel LA …

The Emerging Value Of The Viroid Model In Understanding Plant Responses To Foreign Rnas, Junfei Ma

Theses and Dissertations

RNAs play essential roles in various biological processes. Mounting evidence has demonstrated that RNA subcellular localization and intercellular trafficking govern their functions in coordinating plant growth at the organismal level. Beyond that, plants constantly encounter foreign RNAs (i.e., RNAs from pathogens including viruses and viroids). The subcellular localizations of RNAs are crucial for their function. While numerous types of RNAs (i.e., mRNAs, small RNAs, rRNAs, tRNAs, and long noncoding RNAs) have been found to traffic in a non-cell-autonomous fashion within plants, the underlying regulatory mechanism remains unclear. Viroids are single-stranded circular noncoding RNAs, which entirely rely …

Bobcat Identification, Abundance, And Behavior At Road Mitigation Structures In South Texas, Victoria Hanley

Theses and Dissertations

Highways in South Texas fragment the landscape and result in high road mortality rates for the endangered US ocelot (Leopardus pardalis). In response, the Texas Department of Transportation constructed nine wildlife crossing structures (WCS) on Farm-to-Market (FM) 106 which adjoins Laguna Atascosa National Wildlife Refuge in Cameron County, Texas. With ocelots being rare and elusive, bobcats (Lynx rufus) are often used as a surrogate species to study felid behavior at road mitigation structures in South Texas. Bobcats have unique markings which allow them to be individually identified. Three methods of individual identification of bobcats using camera …

The Molecular Evolution Of Insect Opsin Genes, Maria Jose Cardenas Muedano

Theses and Dissertations

Opsins are part of the superfamily of G-coupled receptor proteins and together with chromophores, are responsible for initiating the signal transduction cascade responsible for animal vision. Since opsins have a critical role on visual perception these genes are crucial for a myriad of adaptive traits and behaviors and should show diverse signs of natural selection at the molecular level. Understanding the evolution of opsins across the wide diversity of insect groups will allow us to better understand the evolutionary pressure on insect opsins and serve as a model for both other gene systems and other taxonomic groups of animals that …

Foxo Factors Regulate The Expression Of Canonical Wnt Target Genes In A Set Of Basal-Like Breast And Glioblastoma Multiforme Cancer Cell Lines, Shania Pintor

Theses and Dissertations

Basal-like breast cancer (BBC) and Glioblastoma Multiforme (GBM) each express stem gene expression signatures which are partly driven by FOXO transcription factors. Preliminary data from Gene Set Enrichment Analysis (GSEA) with RNA Seq. data indicated that a set of WNT target genes including LEF1, and TCF7 were robustly induced after 48-hours of AS1842856 (FOXO1 inhibitor) treatment. These same genes were also induced in GBM cell lines U87MG, LN18, LN229, A172, and DBTRG upon treatment with AS1842856. In contrast to FOXO1 inhibition, RNAi targeting of FOXO1, led to reduced LEF1, and TCF7 gene expression in BT549 and U87MG …

Effects Of Disturbance (Mowing) On Florivory And Floral Defenses In Solanum Elaeagnifolium, A Noxious And Worldwide Invasive Weed, Alejandro Rafael Vasquez Marcano

Theses and Dissertations

Chapter 1: Literature Review- In this literature review we have examined weed management as it concerns urban and agricultural ecosystems, as well as the need for mowing assessments as it relates to floral traits and defense against herbivory.

Chapter 2: Experiments- In the experiments we examined the role of mowing on floral growth traits, floral defense traits, and their effect on Manduca sexta specialist herbivores.

Chapter 3: Results- In the results we found SLN flowers to have larger diameters than unmowed flowers; however, flower mass was in line with our predictions as unmowed flowers were heavier in high mowing frequency …

Wildlife Road Mortality Patterns In South Texas And Survey Methodology Improvement, Bradley E. Beer

Theses and Dissertations

Mortalities of wildlife caused by collisions with vehicles along roads are increasing in prevalence, threatening the existence of various species and populations. A better understanding of how mortalities change in response to natural and anthropogenic variables and efficient methods of obtaining mortality data are essential to mitigating such mortalities. This thesis investigates several key elements to improving road mortality surveys in south Texas. First, it was found that road mortality survey counts did not change under a pandemic-related lockdown and that 2 mortality survey observers detect more mortalities than 1. Analysis of brown pelican groundings on Texas State Highway 48 …

Natural Variation Of Fructose-1,6-Bisphosphatase In Colias Butterflies, Andrea Blair Stokes

Theses and Dissertations

In a process known as the evolutionary recursion, it is possible to follow how adaptation affects natural selection at successive stages of a species’ life cycle. Through studying allele and genotype frequencies of enzymes in glycolysis, a central metabolic pathway, it is possible to document how polymorphisms can shift the evolving functionality of enzymes within or among species. Fructose-1,6-bisphosphatase (FBPase) is an enzyme in gluconeogenesis that converts fructose-1,6-bisphosphate to fructose 6- phosphate. It is also known to convert the unused amino acid carbon skeletons of glycolysis into glycogen storage. Appearing to play a vital role in the acquisition, storage, and …

Uncovering The Diverse Roles Of The Human Cst (Ctc1-Stn1-Ten1) Complex In Resolving Genomic Stress, Percy Logan Schuck

Theses and Dissertations

The CST (CTC1-STN1-TEN1) complex is a heterotrimeric single-stranded DNA binding protein known to stimulate polymerase α-primase (Pol α) and promote telomere length regulation, genome-wide DNA replication and double strand break repair. However, much of its cellular function remains unknown. The focus of my dissertation work was to uncover novel roles of CST in DNA stress response pathways. In particular, my work relates to understanding the function of CST in sister chromatid cohesion (SCC) and base excision repair (BER) as well as characterizing CST protein interactions. SCC is established following DNA replication by loading of the cohesion complex, which encircles replicated …

Nup211 Plays An Important Role In Regulating Mrna Export And Stress Response, Ayana Ikenouchi

Theses and Dissertations

Nup211 is a nuclear pore basket component in Schizosaccharomyces pombe and roles in the gating functions of NPCs. Using RT-qPCR, I found that in nup211-shutoff cells, the transcript levels of genes in mRNA export and stress-response pathways were significantly changed, suggesting nup211 is involved in regulating stress response pathways.

Effects Of Mass Death On Community Structure And Ecosystem Function, Abby Kimpton Jones

Theses and Dissertations

Death and decomposition are natural processes that are generally well-understood. However, large events of death, such as mass mortality events (MMEs) are increasing in frequency and their impacts on the ecosystem are largely unknown. These events may have both bottom-up effects from increased nutrient input as well as top-down effects from loss of an ecological functional group by the affected population. Different functional MMEs may result in different top-down effects, creating cascading effects. In Chapter 1, I test the hypothesis that scavenger and herbivore simulated MMEs generate novel bottom-up and top-down effects. Results indicate that MMEs have a significant effect …

Effects Of Anthropogenic Global Change On A Grassland Prairie Community, Carter Wolff

Theses and Dissertations

Anthropogenic global change is altering food web dynamics. Global change comprises factors, like temperature, sound, light and more. In this dissertation, I evaluate how two factors, sound and temperature, alter prairie communities. In Chapter 1, I test if sound influences grasshopper respiration rate, thereby altering diet. Some sound frequencies increased grasshopper respiration rate while others decreased respiration rate. Frequencies that elevated respiration rate led to grasshoppers consuming more carbohydrate-rich foods compared to protein-rich foods. This diet change stems from a carbon deficit due to increased respiration rate and could act as a mechanism by which sound pollution indirectly alters plant …

Cytochrome C: A Potential Early Biomarker Of Diabetic Retinopathy, Ileana G. Villarreal

Theses and Dissertations

Diabetic retinopathy is an ocular disease which appears in patients who experience progression of diabetes mellitus over a continuous period. Oftentimes, patients go undiagnosed due to the fact that there is no way to determine when the exact moment a patient develops diabetic retinopathy. Ophthalmologists and other eye specialists diagnose a patient with diabetic retinopathy once the patient begins to show progressed symptoms of the disease. Various experiments have been previously performed to increase our knowledge of the connection of diabetic retinopathy and early biomarkers of the disease. Several studies have determined the effects of diabetic retinopathy and apoptosis with …

De Novo Transcriptome Analysis Of Orange Jasmine (Murraya Paniculata) Infected With Citrus Greening Disease, Jeffrey Aquino Gomez

Theses and Dissertations

Citrus greening disease, also known as Huanglongbing, is one of the most devastating citrus diseases in the world. Candidatus Liberibacter asiaticus (CLas) is a non-culturable, phloem-limited bacterium that serves as one of two vectors for the transmission of any of the three kinds of greening disease. In cooler climates, the African variant transmitted by the African citrus psyllid (Trioza erytreae) is more prevalent. The Asian form transmitted by the Asian citrus psyllid (Diaphorina citri) where is predominant in warmer conditions and recently discover the American form who is also transmit by Diaphorina citri, was discover in Brazil but has also …

Examination Of Amphibian Community And Environmental Relationships In South Texas Using Environmental Dna (Edna), Sean Michael Collins

Theses and Dissertations

Developing more efficient tools to assess amphibian biodiversity and understanding what environmental variables drive amphibian biodiversity are top priorities, as amphibians are facing extinction events across the globe. Environmental DNA (eDNA) surveys are a promising new tool to asses amphibian biodiversity. Throughout the study eDNA metabarcoding along with a targeted eDNA assay and traditional survey methods were used to provide foundational information on amphibian community assemblages throughout South Texas. Water quality, habitat characteristics and soil composition data were collected and used to examine environmental relationships. eDNA metabarcoding detected significantly more amphibian taxonomic units compared to traditional survey …

Molecular And Morphological Investigations Of Grouper (Serranidae) Biodiversity In Saudi Arabia, Mohammad Saeed Al Jazza Alqahtani

Theses and Dissertations

Chapter 1: The seas surrounding the Arabian Peninsula, which represent the northernmost portion of the Indian Ocean, are considered to have the highest aquatic biodiversity among the worlds marine regions. Seas that surround the Arabian Peninsula include the Red Sea, the Gulf of Aden, the Arabian Sea, the Gulf of Oman, and the Arabian Gulf. In aggregate, this area harbors a large number of endemic and more widespread marine species, including fishes, echinoderms, and corals.

There are unique challenges involved in grouper species identification in the Arabian region including ‘familiar’ Arabic species designations that are not standardized in the Arabic …

Methyltransferase Mystery: Epigenetic Mechanisms Induced By Food Limitation In Daphnia Pule, Trenton C. Agrelius

Theses and Dissertations

Daphnia are ecologically important organisms that have been well studied in the context of evolution, ecology, ecotoxicity, and genomics. Daphnia have strong maternal effects in which the environment experienced by the mother can alter offspring disease resistance, life history traits, and morphology, as well as gene expression and methylation for multiple generations. Coupled with their ability to reduce genetic differences via parthenogenesis, Daphnia are an ideal system for epigenetic studies involving the transmission of maternal effects. Using two clones of Daphnia pulex, we investigated the plasticity of life history and DNA methyltransferase (Dnmt) gene expression with respect to food …

In Vivo And In Vitro Investigations Of Mammalian Stem Cell Development: Neurogenesis And Pituitary Progenitors, Allison Culver

Theses and Dissertations

Human development is tightly regulated by complex mechanisms to pattern the early embryo and form specialized tissues. Understanding this regulation is of fundamental importance and can help further understand disease pathologies. Because it is difficult to observe the processes of interest, researchers must rely on the use of model systems. Our research goal is to combine both animal models and in vitro stem cell cultures to address key questions about the mechanisms of development for both the pituitary gland and brain. It is estimated that there are 290-455 cases per million of congenital hypopituitarism. In addition, autism spectrum disorder (ASD) …

Mechanisms Of Connectivity In Neuronal Development, Janay Vacharasin

Theses and Dissertations

The development of neuronal connectivity requires the careful orchestration of multiple cellular processes including the control of neuronal arborization and synapse formation or function. Defects in these processes during neuronal development will give rise to disorders of neuronal connectivity like autism. In the present work, we examine the genetic and epigenetic mechanisms that build the neuronal wiring of the developing brain. We use human stem cell-derived neurons to study neuronal arborization and function focusing on genetic and environmental risk factors of neurodevelopmental disorders that include autism and intellectual disability. Specifically, we focused on the contribution of the endomembrane, chromatin, and …