Molecular Biology Commons^™

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. …

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 …

Phosphatidylserine Externalization On Non-Apoptotic Cells And Lipid Scramblases In C. Elegans, Julia Frondoni

Electronic Theses and Dissertations

Cell corpse clearance is key for animals to avoid inflammation and autoimmune disease. To better understand the “eat me” signal of phosphatidylserine (PS) exposure for non-apoptotic corpse clearance, we attempted to disrupt the externalization of PS on C. elegans polar bodies. The second polar body undergoes a non-apoptotic form of cell death, loses membrane integrity, externalizes PS and is cleared by embryonic cells during early development. During apoptotic and necrotic cell death, PS asymmetry is disrupted by lipid scramblases, which translocate phospholipids between the leaflets of the lipid bilayer. We found neither apoptotic nor necrotic scramblases are required for PS …

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 …

Uncovering Transcriptional Activators And Targets Of Hsf-1 In Caenorhabditis Elegans, Jessica Brunquell

USF Tampa Graduate Theses and Dissertations

In order to survive, cells must be able to cope with a variety of environmental stressors. The heat shock response (HSR) is a pro-survival mechanism employed by cells in response to protein denaturing stress, such as heat. Since its discovery in 1960, the heat shock response has been found to be regulated by the transcription factor heat shock factor 1 (HSF1). During periods of increased stress, HSF1 undergoes a multi-step process of activation that involves homotrimerization, DNA-binding, and post-translational regulatory modifications, all of which ultimately function to control the transcription of chaperone genes. These chaperone genes encode molecular chaperone proteins …

Reactive Oxygen Species-Mediated Neurodegeneration Is Independent Of The Ryanodine Receptor In Caenorhabditis Elegans, Lyndsay E.A. Young, Daniel C. Williams

Journal of the South Carolina Academy of Science

Despite the significant impacts on human health caused by neurodegeneration, our understanding of the degeneration process is incomplete. The nematode Caenorhabditis elegans is emerging as a genetic model organism well suited for identification of conserved cellular mechanisms and molecular pathways of neurodegeneration. Studies in the worm have identified factors that contribute to neurodegeneration, including excitotoxicity and stress due to reactive oxygen species (ROS). Disruption of the gene unc-68, which encodes the ryanodine receptor, abolishes excitotoxic cell death, indicating a role for calcium (Ca²⁺) signaling in neurodegeneration. We tested the requirement for unc-68 in ROS-mediated neurodegeneration using the …

The Effects Of Supplemented Metabolites On Lifespan And Stress Response Pathways In Caenorhabditis Elegans, Clare B. Edwards

USF Tampa Graduate Theses and Dissertations

Understanding how metabolites contribute to anaplerosis, antioxidant effects, and hormetic pathways during aging is fundamental to creating supplements and dietary habits that may decrease age-associated disease and decline, thus improving the quality of life in old age. In order to uncover metabolic pathways that delay aging, the effects of large sets of metabolites associated with mitochondrial function on lifespan were investigated.

Malate, the tricarboxylic acid (TCA) cycle metabolite, increased lifespan and thermotolerance in C. elegans. Addition of fumarate and succinate also extended lifespan and all three metabolites activated nuclear translocation of the cytoprotective DAF-16/FOXO transcription factor and protected from paraquat-induced …

Sirt1 Regulation Of The Heat Shock Response In An Hsf1-Dependent Manner And The Impact Of Caloric Restriction, Rachel Rene Raynes

USF Tampa Graduate Theses and Dissertations

The heat shock response (HSR) is the cell's molecular reaction to protein damaging stress and is critical in the management of denatured proteins. Activation of HSF1, the master transcriptional regulator of the HSR, results in the induction of molecular chaperones called heat shock proteins (HSPs). Transcription of hsp genes is promoted by the hyperphosphorylation of HSF1, while the attenuation of the HSR is regulated by a dual mechanism involving negative feedback inhibition from HSPs and acetylation at a critical lysine residue within the DNA binding domain of HSF1, which results in a loss of affinity for DNA. SIRT1 is a …