Digital Commons Network^™

Rnai “Flexon” Approach To Gonad Gene Knockdown In C. Elegans, Sofia Suzanne Douglas

Undergraduate Theses

All living things require some form of genetic regulation so that gene products are correctly produced and maintained. One significant form of post-transcriptional gene expression is RNA silencing, a biological mechanism in which double stranded RNA molecules inhibit gene expression by blocking translation of targeted mRNA molecules. Due to its extensive applications in biotechnology, it’s been adapted as an experimental technique referred to as RNAi. This technique is temporary, transient, and easy to use. A new form of RNAi, referred to as the “Flexon” technique, is a novel approach that provides a method for post-transcriptional gene regulation that allows for …

Exploring The Potential Pathogenicity Of A Type 2 Diabetes Mellitus Associated Insr Missense Variant Of Uncertain Significance Through Daf-2 In The Caenorhabditis Elegans Model, Brittany White

Theses

Type 2 diabetes mellitus (T2DM) is hallmarked by insulin resistance, with the INSR gene identified as a key player in this condition in humans. This gene is known to harbor genetic variants with a wide range of clinical significance from pathogenic to variants of uncertain significance (VUS) to benign. This project investigates a VUS associated with T2DM identified through ClinVar. A gene mutational analysis, predictive amino acid substitution analysis, and protein modeling predict INSR c.1628C>T (p. Thr543Met) to be likely pathogenic or damaging. PolyPhen-2 predicts this variant to be probably damaging (HumDiv score of 1.000).

Evolutionary conservation of the …

Csn-5: A Tumor's Friend Or Foe In The C. Elegans Germline?, Kellie C. Kuch

Graduate Student Theses, Dissertations, & Professional Papers

The COP9 signalosome is a highly conserved eukaryotic complex regulating protein degradation via deneddylation of Cullin-RING E3 ligases. CSN5, the COP9’s fifth component, contains the catalytically active domain for CSN deneddylation. The complex is inactive without CSN5; however, CSN5 engages in COP9-independent binding with several other proteins, typically promoting either destruction or stabilization of its partners. Many of its confirmed interaction partners are also implicated in tumorigenesis (prominent examples being p27 and p53) and a complex cancer interactome has been established for CSN5. Additionally, CSN5 overexpression has been documented in a staggering array of cancers of diverse origins. This discovery …

The Role Of Semaphorins In Response To Injury In C. Elegans Neurons, Maria Belen Harreguy Alfonso

Dissertations

When neural tissue is injured by trauma, delicate neuronal processes such as axons and dendrites are prone to lesion damage and often disconnect. The molecular, cellular, and circuit mechanisms that underlie the regrowth and reconnection of these processes and the recovery of behavior are major challenges in the fields of neuroscience, regeneration, and resilience. At the molecular and cellular levels, signaling pathways that mediate neuronal growth cone guidance during development can play a role in neuronal regeneration and recovery from injury. One family of signaling proteins involved in this process comprises the highly conserved semaphorins and their receptors, the plexins. …

Pathogenicity Of Acinetobacter Calcoaceticus, Kaitlan A. Sullivan

MUSC Theses and Dissertations

Acinetobacter is a genus of gram-negative bacteria that have been appearing frequently in hospitals contributing to infections in the blood, lungs, urinary tract, and other parts of the body. It infects patients with weakened immune systems that are placed on ventilators, after the use of catheters, or have any other open wounds produced by prolonged hospital stays. This genus of bacteria is problematic due to its high probability of becoming resistant to multiple classes of antibiotics. Thus, we are determining the pathogenicity of clinical isolates of Acinetobacter calcoaceticus using the organism Caenorhabditis elegans as a model.

We are testing …

Detection And Control Of Environmentally Transmissible Viruses, Anand R. Soorneedi

Doctoral Dissertations

Viruses, owing to their ubiquitous nature and ability to infect almost every other species, have long been a subject of interest for scientists. Some of the virus species can be very deadly to humans and animals alike and can impose a huge economic and health burden across the world. The recent CoVID-19 pandemic underscores the importance of timely detection for developing effective intervention strategies. Unfortunately, some of the virus species that cause significant health and economic impacts do not have robust and reliable detection methods due to several reasons. In some cases, despite having gold standard methods for detection of …

Exploring The Impact Of Pqn-75 And Glh-1/Vasa On Germline Development, Maintenance, And Gsc Reprogramming Using Caenorhabditis Elegans As A Model, Jesse D. Rochester

Electronic Theses and Dissertations

This thesis combines research on PQN-75 expression, functional motifs of GLH-1/Vasa, and germ granule components in Caenorhabditis elegans to provide a comprehensive understanding of germline development, maintenance, and reprogramming, while also examining the role of pharyngeal gland cells in stress resistance and thermotolerance. In C. elegans, pharyngeal gland cells secrete mucin-like proteins, such as PQN-75, with similarities to human PRB2. The expression of PQN-75 in gland cells confers stress resistance and thermotolerance but does not affect fertility, instead it plays a role in the organism's ability to adapt to varying environmental conditions. While, GLH-1/Vasa, an ATP-dependent DEAD-box helicase, plays …

An Evolutionary Comparative Study Of Congenital Stationary Night Blindness-Associated Trpm1 Genetic Variants Of Uncertain Significance In Horses And Humans Utilizing Caenorhabditis Elegans, Gabrielle Davis

Theses

Congenital stationary night blindness (CSNB) is a heterogeneous collection of genetic diseases affecting the eyes and vision in horses and humans. Current research has implicated several genetic mutations impacting different genes involved in phototransduction and signal transmission, including TRPM1. In horses, genetic mutations in TRPM1 also result in a leopard spotting pattern or leopard complex. The goal of this study is to examine the potential impact of CSNB associated TRPM1 missense variants of uncertain significance (VUS). Previous research in Caenorhabditis elegans have revealed an orthologous TRPM1 gene known as gon-2 that allows for comparative studies. The evolutionary relationship of …

An Investigation Into Transcription Fidelity And Its Effects On C. Elegans And S. Cerevisiae Health And Longevity, Olivia S. Dinep-Schneider

Theses and Dissertations

mRNA molecules form an intermediate in the transfer of sequences from DNA to ribosomes in order to guide protein production. Errors can be introduced into mRNA, producing aberrant proteins which place a strain on cellular regulatory machinery, causing increased risks of apoptosis, cancer, and decreased fitness. These errors may be introduced due to decreased transcriptional proofreading capabilities, exposure to chemicals, or mistakes in RNA editing machinery. It is important to investigate these causes of transcription errors to better understand the long-neglected area of mRNA fidelity which has such significant impacts on our cellular functions. In this paper, it was determined …

Reverse Genetics: Downregulating Chk-1 And Fasn-1 In The Gonads Of C. Elegans, Sam Thompson

Undergraduate Theses

Despite its widespread use in research, the model organism C. elegans has several biological processes like gonadal development with potentially unexplored genetic regulators. Previous transcriptome analysis has identified several genes that are upregulated in a specific tissue or sex during the development of the somatic gonad in C. elegans (Kroetz et al. 2015) that have not been previously connected to this process. Of these genes, this research is concerned with chk-1 and fasn-1. Abrogating the expression of these genes in gonadal tissue during gonadogenesis could cause a change in phenotype for affected C. elegans that would aid in understanding these …

Nicotinamide Riboside And Beta-Hydroxybutyrate Activate Parallel Pathways For C. Elegans Lifespan Extension, Mckenzie Peters

Undergraduate Honors Theses

Supplementation with nicotinamide riboside (NR), a form of vitamin B3 and a precursor of nicotinamide adenine dinucleotide (NAD⁺) extends lifespan in the nematode C. elegans and delays aging-related pathologies in mammals. During aging, levels of NAD⁺ decline causing metabolic dysfunction and oxidative damage. Studies in C. elegans found that when NR was administered during larval development it induced the mitochondrial unfolded protein response (UPR^mt), which is frequently associated with lifespan extension. Both calorie restriction (CR) and ketogenic diets (KD) have been shown to extend lifespan, in part through increasing NAD⁺ and through increasing levels …

The G Protein-Coupled Receptor (Gpcr) Fshr-1 And The Sphk-1 Lipid Kinase Regulate C. Elegans Life- And Healthspans Via A Common Pathway, Ryan Dennis Adkins

Undergraduate Honors Thesis Collection

Later years of life are often characterized by reduced cognitive function and mobility. One contributor is the cellular accumulation of reactive oxygen species (ROS), but our understanding of how cells respond to ROS to promote health and survival is incomplete. Follicle stimulating hormone receptor-1 (FSHR-1) and sphingosine kinase-1 (SPHK-1) mediate responses to oxidative stress and regulate life history traits in the roundworm Caenorhabditis elegans. The genes encoding both proteins are conserved in humans where they are implicated in stress responses, cell survival and neuronal function. fshr-1 and sphk-1 work together to mediate responses to intestinal oxidative stress in C. elegans. …

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. …

Using Crispr To Genetically Engineer Two Genes Involved In Gonadogenesis In The Model Organism C. Elegans, Peyton Young

Undergraduate Theses

C. elegans is a nematode model organism commonly used in research because of its small size and similarity to humans. Of the known protein sequences of C. elegans, 40%-80% have human homologous genes, making C. elegans an ideal organism for study of human proteins (Lai et al. 2000). Additionally, there are two sexes of C. elegans, male and hermaphrodite. Of the two sexes, this research focuses on the males, especially the development of the gonad and the genes involved in this process. Two genes were chosen for study, C10E2.6 and pig-1, based on essentiality and mRNA expression …

Tgf-B Signaling Mechanisms In Caenorhabditis Elegans Response To Bacterial Pathogens, Emma J. Ciccarelli

Dissertations, Theses, and Capstone Projects

When exposed to infection, the nematode C. elegans mounts an innate immune response through secretion of antimicrobial peptides (AMPs). Different signaling pathways in the worm regulate release of these AMPs. One highly conserved pathway is the C. elegans BMP like pathway – regulated by the ligand DBL-1. The DBL-1 pathway is noted for its significant role in development but has also been shown to regulate many post-developmental processes within the worm, including the immune response. We are interested in determining how DBL-1 signaling can mediate a response specific to immunity, separate from its other functions in the worm. Through survival …

Interrogating Centrosome Protein Dynamics, Centriolar Satellite Regulation Mechanisms, And Autofluorescence Characterization Of Caenorhabditis Elegans Using Förster Resonance Energy Transfer-Fluorescence Lifetime Imaging Microscopy (Fret-Flim) And Fluorescence Microscopy, Elizabeth A. Cameron

WWU Graduate School Collection

Centrosomes are required for human cells to divide and differentiate into the many different embryonic tissues that form throughout development. Mutations that drastically disrupt centrosomes cause embryonic lethality and cancer. More subtle mutations cause congenital birth defects including blindness, olfactory deficits, and limb, heart, and brain malformations. PCNT is an essential human gene that encodes for the centrosome protein Pericentrin. Pericentrin organizes the structure of the centrosome by serving as a scaffold protein. Pericentrin also interacts with other centrosome proteins, which play a role in centrosome-mediated microtubule formation. Additionally, Pericentrin recruits enzymes that are involved in centrosome duplication and maturation, …

Investigations Into The Negative Impact Of Temperature Stress On Fertility In Wild Strains Of Caenorhabditis Elegans, Nicholas B. Sepulveda

Dissertations (1934 -)

Sexual reproduction and its coincident genetic recombination are powerful adaptive strategies. However, sexual reproduction has disadvantages. One ancient and conserved disadvantage is temperature sensitivity. In organisms diverse as plants, insects, nematode worms, and humans, as temperatures increase, fertility decreases. The goal of this dissertation is to examine the negative impact of elevated temperature stress on fertility in sexually reproducing organisms using wild strains of Caenorhabditis elegans. C. elegans presents a unique opportunity to study these effects broadly in two contexts, as worms may be either self-fertile hermaphrodites that produce both egg and sperm or males which produce only sperm. In …

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 …

Regulation Of The Heat Shock Response Via Lysine Acetyltransferase Cbp-1 And In Neurodegenerative Disease In Caenorhabditis Elegans, Lindsey N. Barrett

USF Tampa Graduate Theses and Dissertations

The decline of proteostasis is a hallmark of aging that is, in part, affected by the dysregulation of the heat shock response (HSR), a highly conserved cellular response to proteotoxic stress in the cell. The heat shock transcription factor HSF-1 is well-studied as a key regulator of proteostasis, but mechanisms that could be used to modulate HSF-1 function to enhance proteostasis during aging are largely unknown. In this study, we examined lysine acetyltransferase regulation of the HSR and HSF-1 in C. elegans. We performed an RNA interference screen of lysine acetyltransferases and examined mRNA expression of the heat-shock inducible gene …

Novel Strategies For Glutamate Clearance In The Glia-Deprived Synaptic Hub Of C. Elegans, Joyce Chan

Dissertations, Theses, and Capstone Projects

As the major excitatory neurotransmitter in the mammalian brain, Glutamate (Glu) is critical for normal neuronal physiology. Disruption in Glu clearance results in hyper-stimulation of glutamatergic circuits, potentially leading to excitotoxic neurodegeneration. The canonical model of brain connectivity describes glutamatergic synapses as well insulated and enveloped by glia. These glia express Glu Transporters (GluTs) which work to clear Glu following synaptic activity. However, critical areas of the brain such as the mammalian hippocampus display poor synaptic isolation, which may result in Glu spillover between adjacent synapses and subsequent loss of circuit specificity. How accurate signal transmission is achieved in these …

Membrane Palmitoylated Protein Magu-3 Regulates The C. Elegans Locomotor Circuit Via Modulation Of Cholinergic Activity, Henry Richburg

Theses and Dissertations--Medical Sciences

Precise coordination of the activity and transmission in excitatory and inhibitory neural circuits is essential for healthy information flow. Synaptic scaffolding proteins play a key role in the regulation of circuit activity through the localization and organization of receptors, channels, and other synaptic machinery to facilitate signal transduction. Using the C. elegans motor circuit which has both cholinergic (excitatory) and GABAergic (inhibitory) inputs onto muscles, we revealed an unexplored role of a family of scaffolding molecules known as membrane palmitoylated proteins (MPPs). Here, we examined magu-3, a C. elegans ortholog within the membrane palmitoylated protein family, using GFP tagging …

The Effect Of Ethanol On Cellular Movements And Development In C. Elegans, Caitlin N. O'Connor

West Chester University Master’s Theses

Neural tube development, which gives rise to the central nervous system, is vital to embryonic development. Neural tube defects, like spina bifida, are serious and common congenital defects which can result in life-long medical complications. Folic acid has been used as a preventative measure for neural tube defects and has appeared to decrease the occurrences of neural tube defects. However, the mechanism behind folic acid’s role in neural tube development is unclear. Furthermore, some evidence suggests that ethanol decreases the levels of folates and folate coenzymes in the fetal brain and downregulates folic acid metabolism genes. To better understand the …

An Investigation Into The Mechanism Of Proteasome Dysfunction In Neurodegenerative Disease And The Biological Impact Of Proteasome Hyperactivation In C. Elegans, Raymond T. Anderson

Graduate Theses, Dissertations, and Problem Reports

Aging is an inevitable process that occurs as humans grow older. It is characterized by the chronological accumulation of cellular damage over time leading to functional decline as an organism grows older. Several processes are thought to contribute to the aging phenomenon, but one of the most prolific of these is the disruption of protein homeostasis (proteostasis). The collapse of proteostasis can lead to accelerated aging and the development of age-related diseases including devastating neurodegenerative diseases (NDs) like Alzheimer and Parkinson disease. Virtually all NDs are characterized by the buildup of proteins in and around neurons resulting in neuronal death …

The Effects Of Chronic Ethanol Exposure On Caenorhabditis Elegans Germline, Andrea Zegarra

Seton Hall University Dissertations and Theses (ETDs)

Ethanol is the most commonly abused drug in the world. Alcohol consumption increases a number of health risks, morbidity and mortality, and chronic and acute diseases. Some health risks include high blood pressure, stroke, liver disease, cancer, and can include mental health and social problems. Chronic alcohol consumption can lead to learning and memory problems, along with alcohol dependence. Additionally, alcohol consumption has an impact on ovarian reserve, steroid hormone production, sperm quality, fecundity, and fertility treatments. The purpose of this study was to analyze the effects of ethanol exposure on fertility of the N2 wild type as measured by …

Elucidating The Modulatory Role Of Dopamine In The C. Elegans Chemosensory Ash Neuron, Cory Kunkel

Electronic Theses, Projects, and Dissertations

The neurotransmitter dopamine regulates chemosensory avoidance behavior in the model organism Caenorhabditis elegans. Avoidance behaviors are mediated by the polymodal ASH nociceptive sensory neurons, and behavioral avoidance of stimuli detected by ASH is less robust when dopamine signaling is impaired. We are investigating the neural response of the ASH neurons to various stimuli; our investigation includes the behavioral and physiological responses from the ASH neurons as dopamine signaling is manipulated to better understand the effects of dopamine on these sensory neurons. We hypothesize that dopamine plays a regulatory role on the ASH neurons, lessening the response of the ASH …

Investigation Of Fshr-1 Site Of Action And Signaling Initiation At The C. Elegans Neuromuscular Junction, Alyssa Lynn Ritter

Undergraduate Honors Thesis Collection

Millions of neurons in our bodies relay messages to various organ systems. Neuronal signaling involves a combination of electrical and chemical signals between neurons that create responses in the receiving neuron that are either inhibitory or excitatory. The nervous system relies on the balance between excitatory and inhibitory signaling (E:I balance) to maintain its function. G protein-coupled receptors (GPCRs) are cell surface proteins that play critical roles in regulating neuronal signaling by binding molecules that initiate intracellular relay pathways. One conserved GPCR known as FSHR-1, homologous to human follicle stimulating hormone (FSH) receptor, regulates neuromuscular signaling in Caenorhabditis elegans roundworms. …

Density Dependent Growth Of Pseudomonas Fluorescens In The Presence And Absence Of C. Elegans Predation In Liquid Media, Jack Landmann

Honors Theses

The purpose of this study was to understand the predator-prey relationship between C. elegans worms and P. fluorescens bacteria in liquid media. We were aiming to create a predation model of the relationship between these two species.

This study was performed through three experiments. Using 96-well plates, we were able to measure the change in optical density (OD) of these wells and calculate the growth rate. This growth rate was then graphed and analyzed. The first experiment contained P. fluorescens and KB liquid media, this study demonstrated that the bacterial population has a carrying capacity. We were also able to …

A Computational Investigation Of The Biophysical Mechanisms Underlying Thermotaxis In The Afd Neurons Of Caenorhabditis Elegans, Zachary Mobille

Theses and Dissertations

Thermotaxis in the nematode Caenorhabditis elegans (C. elegans) is studied at the cellular scale of the amphid finger-like ciliated (AFD) neurons, which have previously been shown to be essential for thermoreception. The voltage and calcium signals of AFD during temperature stimuli are described with ordinary differential equations. The primary calcium model is a modified version of that published by Kuramochi and Doi in 2017 to explain the calcium responses of the chemosensitive amphid single-ciliated right (ASER) neuron to fluctuations in extracellular salt concentration. To account for the effects of temperature, changes to the stimuli conditions under which inactivation takes place …

Genetic Determinants Of Increased Outcrossing In Caenorhabditis Elegans Following Dauer Diapause, Rose Al-Saadi

Theses - ALL

Mating strategies, whether sexual or asexual, confer unique costs and benefits to populations and species that facilitate evolutionary processes. In wild isolates of Caenorhabditis elegans, mating strategies are dependent on developmental history. Outcrossing levels significantly increase when both hermaphrodites and males have transiently passed through the stress-resistant dauer diapause stage (postdauers). However, the molecular mechanisms of how life history can alter mating strategies have not been systematically explored. Mating behaviors of C. elegans can be attributed, in part, to sex-specific responses to ascaroside pheromone components. For example, high concentrations of the pheromone ascr#3 results in a strong avoidance response in …

Regulation Of The Heat Shock Response And Hsf-1 Nuclear Stress Bodies In C. Elegans, Andrew Deonarine

USF Tampa Graduate Theses and Dissertations

The Heat Shock Response (HSR) is a highly conserved stress responsive molecular pathway that functions to promote appropriate protein folding in the cell. The HSR accomplishes this primarily through the use of molecular chaperones that serve to bind to misfolded or unfolded proteins to assist in stabilizing and folding proteins back to their native functional state. The master regulator of this pathway is a transcription factor known as Heat Shock Factor 1 (HSF1). HSF1 regulates molecular chaperone expression in the cell’s basal state, but can also be stress induced by diverse biotic and abiotic signals including thermal shock, oxidative stress, …