Life Sciences Commons^™

Screen For Beneficial Genetic And Chemical Modifiers In Drosophila Models Of Als And Traumatic Brain Injury, Will Bonderer

Biological Sciences Theses and Dissertations

The underlying molecular processes of aberrant protein expression in neurodegeneration are intricate and multifaceted, with ribosome-associated quality control (RQC) emerging as a promising avenue of exploration. Ribosome-associated quality control is integral to cellular function. Its evolutionarily conserved pathway encompasses a network of mechanisms designed to ensure the fidelity of protein synthesis, folding, and degradation within the cells of all eukaryotes. The ribosome, central to protein synthesis, plays a pivotal role in this quality control network, and its malfunction can lead to the accumulation of misfolded or aberrant proteins. In the context of neurodegenerative disorders, this dysfunction can have dire consequences. …

Analyzing Phototaxis And Related Visual Behaviors Among Diverse Species Of Drosophila, Madeline M. Hill

Honors Theses

Phototaxis and related visual behaviors can vary between species, and thus members of the genus Drosophila make an excellent study system to examine the evolution of vision. While some existing research points to these phototactic behaviors arising due to mating requirements or due to their species-specific ecology or environmental factors, there exists a lack of understanding as to why striking behavioral differences can exist between closely related species, or between members belonging to the same genus. The present research seeks to uncover the specifics regarding these discrepancies in visual evolution and aims to provide a foundation of knowledge about visual …

Impairment Of The Glial Phagolysosomal System Drives Prion-Like Propagation Of Huntington’S Disease, Graham Davis

Theses and Dissertations

The ability of glia to tightly regulate neuronal health and homeostasis in the CNS is conserved across species. Yet, despite the ability to degrade protein aggregates, glia are vulnerable to the accumulation of neurotoxic amyloid aggregates during neurodegenerative disease progress, and even exacerbate their spread. A developing narrative highlights glia as a double-edged sword in neurodegenerative diseases: initially capable of dynamically responding to amyloid aggregate-ladened dying neurons but also capable of inducing chronic inflammation and creating seeding-competent amyloid oligomers. Thus, uncovering the mechanisms that allow glia to control aggregate deposition while preventing the neurotoxic effects and seed generation is vital …

Ras/Mapk Signaling Mediates Adipose Tissue Control Of Ovarian Germline Survival And Ovulation In Drosophila Melanogaster, Tancia Bradshaw, Chad Simmons, Rachael Ott, Alissa Richmond Armstrong

Faculty Publications

From insects to humans, oogenesis is tightly linked to nutritional input, yet little is known about how whole organism physiology matches dietary changes with oocyte development. Considering that diet-induced adipose tissue dysfunction is associated with an increased risk for fertility problems, and other obesity-associated pathophysiologies, it is critical to decipher the cellular and molecular mechanisms linking adipose nutrient sensing to remote control of the ovary and other tissues. Our previous studies in Drosophila melanogaster have shown that amino acid sensing, via the amino acid response pathway and mTOR-mediated signaling function within adipocytes to control germline stem cell maintenance and ovulation, …

Effects Of Osmotic Stress On Oxygen Consumption Of Drosophila Cells (Kc167), Ali A. Ahmed, Rajib Hassan, Michael A. Menze

The Cardinal Edge

This article investigates the effect of osmotic stress on a drosophila cell line called Kc167.

The embryonic-derived fly (Drosophila melanogaster) cell line, Kc-167, was employed as a model for water-stress sensitivity in Arthropods. Like mammalian cells, cells derived from the fruit fly contain the same basic set of membranous components found in all eukaryotic cells. A series of experiments were conducted to characterize the mitochondrial repones of Kc167 cells to water stress. Precisely, the oxygen flux in a sealed respirometer chamber containing Kc167 cells was measured under hyperosmotic and control conditions. Mitochondrial uncouplers were used in some experiments for intact …

Characterization Of The Immune Deficiency Pathway During Female Meiosis In Drosophila Melanogaster, Sarah Mashburn

College of Science and Health Theses and Dissertations

Organisms can defend against pathogens by significantly increasing the diversity of their progeny, so that some progeny are more likely to survive infection. This led to the prediction that infection should cause an increase in recombination rates which was seen in a previous study. However, the mechanism that regulates recombination rates in response to infection is not understood and in that study they did not provide a mechanism for how that can occur. In an RNAi screen, our lab found the gene mustard (mtd) is required for normal recombination rates. This gene was previously shown to be part of the …

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 …

The G-Signaling Protein Rcp Controls The Polarized Basement Membrane Deposition In Epithelial Cells, Rebecca M. Brnot

Honors Capstones

Epithelial tissues are the most common type of tissue in the human body, forming the outer layer of the skin and most organs. They are composed of epithelial cells and rely heavily on their cellular architecture, which is organized by an apical-basal polarity, for their function. One critical component for the establishment and maintenance of the epithelial cell architecture is the proper placement of the basement membrane. The basement membrane is a specialized sheet within the extracellular matrix that lines the basal side of epithelial cells, and there is a biological pathway that is responsible for the proper placement of …

An In-Depth Study Of Border Cell Migration Within Drosophila Melanogaster, Leif R. Verace

Honors Capstones

Cell migration plays a key role in many biological processes including embryonic development, tissue morphogenesis, and the metastasis of cancer cells; thus, understanding how this behavior works is highly important. To study cell migration, we use the process of border cell (BC) migration in Drosophila melanogaster, which sees a cluster of cells migrate through a multicellular structure known as the egg chamber found in the Drosophila ovary. Here, I will describe my results in studying the role of a particular kinesin-like gene, CG14535, in BC migration. Through analysis of a mutant for this gene (labelled KC53), RNAi …

Transcriptome Profile In Drosophila Kc And S2 Embryonic Cell Lines, Daniel Klonaros, Jacqueline M. Dresch, Robert A. Drewell

Biology

Drosophila melanogaster cell lines are an important resource for a range of studies spanning genomics, molecular genetics, and cell biology. Amongst these valuable lines are Kc167 (Kc) and Schneider 2 (S2) cells, which were originally isolated in the late 1960s from embryonic sources and have been used extensively to investigate a broad spectrum of biological activities including cell-cell signaling and immune system function. Whole-genome tiling microarray analysis of total RNA from these two cell types was performed as part of the modENCODE project over a decade ago and revealed that they share a number of gene expression features. Here, we …

Understanding The Relationship Between B Chromosomes And Nondisjunction In Drosophila Melanogaster, Ayushi Patel

Honors Scholar Theses

B chromosomes are supernumerary, heterochromatic genetic elements that are found in hundreds of different plant and animal species. Recently, B chromosomes were discovered in a stock of Drosophila melanogaster and are carried at a high copy number of 10-12 B chromosomes per cell. B chromosomes are not known to carry any active genes, but when placed in a wild-type genetic background, they cause a significant increase in the frequency of chromosome 4 missegregation during meiosis. This project aimed to understand the relationship between a female’s B chromosome copy number and how often she passes on too many (or too few) …

Impacts Of Bacterial Evolution On Host Lethality In Drosophila, Andrew Preston

College of Arts & Sciences Senior Honors Theses

Evolution is the process by which species change their genetic traits, such as the pathogenicity of bacteria, over time in response to changes in their environment. Although the genetic mechanisms underlying many evolutionary processes have been revealed, it is still not well understood how opportunistic pathogens, such as Pseudomonas aeruginosa, become virulent. The overall goal of this thesis is to test the Coincidental Evolution Hypothesis, which proposes that the virulence of opportunistic pathogens evolves coincidentally as a by-product of their interaction with their natural predators. I hypothesized that the virulence of ancestral Pseudomonas aeruginosa changes over time if it co-evolves …

Measuring Energy Demands Of Dynamic Remodeling Events During Embryogenesis In Live Drosophila Embryos, Grayson Young

Biological Sciences Undergraduate Honors Theses

Embryonic development is a complex process requiring dynamic cell movements to create complex tissue structures. We assume that these embryonic dynamic remodeling events are highly energy intensive and that this energy expenditure is mediated by mitochondria. However, this has been difficult to demonstrate in live embryos. Convergent extension of the Drosophila neuroectoderm is a promising system to study the bioenergetics of tissue remodeling because it changes from a static to a dynamically remodeling tissue with temporal precision. We hypothesize that the switch from static to dynamic development at the onset of convergent extension will be accompanied by an increase in …

Validating A New In Vivo Model To Study Als, Izabela J. Cimachowska

Student Theses and Dissertations

Buildup of oxidative stress and mitochondrial dysfunction are well known characteristics of both sporadic and hereditary amyotrophic lateral sclerosis (ALS). While both forms of the disease seem to arise from common cellular dysfunction, the genetic disease is studied to a much greater extent. Engineering novel animal models of the sporadic form of the disease is crucial for development of druggable targets to treat ALS and understand the underlying mechanisms. Interestingly, accumulation of oxidative stress by exacerbated emission of reactive oxygen species (ROS) from presynaptic mitochondria is a hallmark of both hereditary and sporadic ALS. Previous work by our laboratory showed …

Effects Of Actin-Destabilizing Drugs On Motor Function In Drosophila Melanogaster, Caden Sullivan

Honors Theses

Actin dynamics influence many cellular processes including neural connectivity and function. One way to better understand and study the regulation of these dynamics is to manipulate actin dynamics and observe the effects in motor function as a proxy to changes on the neuromuscular junctions in developing neural tissue. On that line, this investigation hypothesized that changing the actin dynamics during development via drug manipulation results in observable effects in locomotion. One of the common actin regulatory drugs used throughout the literature includes Latrunculin A, which was used in this study. Methods included applying this actin destabilizing drug on developing wildtype …

Characterizing The Dynamic Localization Of Cmi In Early Drosophila Development, Asra Habibullah

Master's Theses

The COMPASS-like family of lysine methyltransferases, MLR/MLX complexes, are epigenetic regulators that are essential for normal development through the methylation of the fourth lysine residue on histone 3 (H3K4), a universal epigenetic mark associated with active transcription. This family of complexes is highly conserved from yeast to mammals and the genes encoding the human MLR complexes have been associated with various developmental diseases and cancers (Dingwall and Fagan, 2019). In D. melanogaster, the enzymatic methyltransferase core of this complex is composed of two proteins: Cara Mitad (Cmi, also known as Lpt) and Trithorax-related (Trr). Although these proteins have been shown …

The Role Of Cort And Anaphase Promoting Complex/Cyclosome (Apc/C) In Drosophila Sex Determination And Meiosis, Abuzar Sikander Malik

Electronic Theses and Dissertations

The E3 ubiquitin ligase, APC/C, is essential for the completion cell cycle; along with its co-activators it allows mitotic exit and maintenance of G1. APC/C marks various substrates with ubiquitin chains; marked substrates are subsequently destroyed via the 26S proteasome pathway. Cort is a Drosophila female meiosis specific activator of APC/C. Cort works within meiosis in conjunction with Fzy to mediate Securin and cyclin destruction. A C-terminal IR-tail motif and a N-terminal C-box support Cort-APC/C interaction, whereas short motifs like D-box and KEN-box on the target protein impart substrate recognition to Cort. Cort expression is tightly controlled in the female …

Expression Of Htyr In Drosophila As A Novel Model Of Parkinson’S Disease, Madeleine Callan

Scripps Senior Theses

Parkinson’s disease is a debilitating and often deadly neurodegenerative disease affecting a growing and large population. Its etiology has long remained elusive, and because no other organisms have Parkinsonian-like diseases, it is difficult to study PD using model organisms. Neuromelanin (NM), an insoluble melanin synthesized in the dopaminergic synthesis pathway in DA neurons, has recently been implicated in PD as a major causal factor. At high levels in DA lysosomes, it functions as a proteostatic pathway inhibitor–blocking dopaminergic neurons from breaking down harmful molecules until the lysosomes eventually degenerate as well as triggering autophagy, inflammation, and total neurodegeneration. Recently, neuromelanin …

Genetic And Environmental Contributions To Wolbachia-Induced Cytoplasmic Incompatibility, Kelley Van Vaerenberghe

Graduate Student Theses, Dissertations, & Professional Papers

Maternally-transmitted Wolbachia infect the cells of most insect species, but their frequencies in host populations vary. While much of their success can be attributed to their ability to manipulate host reproduction, these manipulations are context-dependent, varying due to several biotic and abiotic factors. Wolbachia’s most common manipulation, cytoplasmic incompatibility (CI), is a conditional sterility phenotype where male-female host compatibility depends on their infection status. Specifically, CI occurs when infected males produce modified sperm that cause increased embryonic lethality unless the female carries a similar infection. Rescuing their eggs from CI increases the relative fitness of infected females, promoting Wolbachia spread …

Regulation Of Tissue Mechanics And Adherens Junctions By Small Gtpase Rhoa During Drosophila Embryogenesis, Hanqing Guo

Dartmouth College Ph.D Dissertations

Actomyosin contractility plays an important role at both the cell and tissue level during developments. In this study, we developed an optogenetic tool that can acutely inhibit actomyosin contractility by targeting its main activator Rho1. This optogenetic tool can achieve myosin inhibition within one minute and thus enable further dissection of actomyosin function in development. In my first two projects, I used Drosophila mesoderm invagination (also known as ventral furrow formation) as a model to study epithelial folding, a fundamental mechanism for constructing complex 3D tissues. Apical constriction mediated by actomyosin contractility is a common mechanism for epithelial folding. However, …

Drosophila Melanogaster As A Model For Male Reproductive System Ethanol Toxicity, Gbemisola Ilelaboye

Seton Hall University Dissertations and Theses (ETDs)

Drosophila melanogaster has been extensively used in different types of research as a model organism due to its high reproductivity, short life span, and easy maintenance. In this paper, we examined drosophila as a model for ethanol toxicity in the male reproductive system. We developed three assays: The DAPI assay, sperm viability assay, and tubulin staining assay. The DAPI assay is a nuclear staining assay that assesses the effects of various ethanol concentrations in late spermiogenesis in which increased detrimental effects to the sperm bundles were observed. The second assay consisted of the sperm viability assay which showed an increase …

Genetic Determinants Of Primary Nociceptor Sensitivity In Drosophila Melanogaster, Christine Hale

Electronic Theses and Dissertations

Abnormal pain affects ~50 million adults nationwide. With many of the current treatment options for chronic pain, such as opioid analgesics, carrying side effects such as the threat for addiction, research into safer and more effective options for chronic pain relief is crucial. Abnormal alterations in nociceptive sensitivity, which is the sensitivity of peripheral sensory neurons that detect noxious stimuli, can underlie, and perpetuate chronic pain. However, much is still unknown about the mechanism of how these abnormal alterations in sensitivity occur. To help elucidate genetic components controlling nociceptive sensitivity, the Drosophila melanogaster larval nociception model has been used …

A Tale Of Two Genomes: The Complex Interplay Between The Mitochondrial And The Nuclear Genomes, Abhilesh S. Dhawanjewar

School of Biological Sciences: Dissertations, Theses, and Student Research

Mitochondria, the product of an ancient endosymbiotic event are pivotal to eukaryotic cells by synthesizing the majority of the cell’s ATP output. However, modern- day mitochondria are completely dependent on more than one thousand nuclear-encoded products for their function and the maintenance of their genomes. The fundamentally different ways in which the mitochondrial (mtDNA) and the nuclear (nucDNA) genomes are replicated and inherited lead to captivating coevolutionary dynamics between them. The aims of this dissertation are to investigate the coevolutionary dynamics between the mitochondrial and nuclear genomes at three distinct biological scales. At the organismal level, we use a Drosophila …

Interchromosomal Interaction Of Homologous Stat92e Alleles Regulates Transcriptional Switch During Stem-Cell Differentiation., Matthew Antel, Romir Raj, Madona Y G Masoud, Ziwei Pan, Sheng Li, Barbara G Mellone, Mayu Inaba

Faculty Research 2022

Pairing of homologous chromosomes in somatic cells provides the opportunity of interchromosomal interaction between homologous gene regions. In the Drosophila male germline, the Stat92E gene is highly expressed in a germline stem cell (GSC) and gradually downregulated during the differentiation. Here we show that the pairing of Stat92E is always tight in GSCs and immediately loosened in differentiating daughter cells, gonialblasts (GBs). Disturbance of Stat92E pairing by relocation of one locus to another chromosome or by knockdown of global pairing/anti-pairing factors both result in a failure of Stat92E downregulation, suggesting that the pairing is required for the decline in transcription. …

Measuring Mtdna In Drosophila, Lola Demurger

WWU Honors College Senior Projects

Mitochondria have long been studied in relation to aging as they are critical to cell operation, and their dysfunction is linked to several age-related factors, such as shortened lifespan and increased innate immunity. In this study, we use a mitochondrially targeted nuclease called UL12.5 to artificially induce mitochondrial dysfunction by degrading the mitochondrial genome in Drosophila. Degraded mitochondrial DNA (mtDNA) has many downstream effects, including mtDNA depletion, mtDNA leakage into the cytoplasm, chronically upregulated innate immune response, and shortened lifespan. We began the process of developing an assay that measured mtDNA depletion as a result of UL12.5-mediated mtDNA degradation in …

Cas9/Nickase-Induced Allelic Conversion By Homologous Chromosome-Templated Repair In, Sitara Roy, Sara Sanz Juste, Marketta Sneider, Ankush Auradkar, Carissa Klanseck, Zhiqian Li, Alison Henrique Ferreira Julio, Victor Lopez Del Amo, Ethan Bier, Annabel Guichard

Journal Articles

Repair of double-strand breaks (DSBs) in somatic cells is primarily accomplished by error-prone nonhomologous end joining and less frequently by precise homology-directed repair preferentially using the sister chromatid as a template. Here, a

Genetic Circadian Mosaics And The Clock Network’S Contributions To Sleep, Lukasz Widziszewski

Dissertations, Theses, and Capstone Projects

Circadian rhythms are physiological and behavioral changes which follow a 24-hour cycle. Drosophila Melanogaster’s circadian clock neuronal network (CCNN) has been identified and several subpopulations have been characterized based on previous studies; the classifications of subpopulations of neurons within the CCNN are based on a return of anticipatory locomotor activity preceding the two daily light transitions (Lights on = dawn/Lights off = dusk). The neurons responsible for the return of anticipatory morning locomotor activity have been referred to as the M-cells, the group of neurons known to rescue evening anticipatory locomotor activity have been termed the E-cells. In this …

A Nickase Cas9 Gene-Drive System Promotes Super-Mendelian Inheritance In Drosophila, Víctor López Del Amo, Sara Sanz Juste, Valentino M Gantz

Journal Articles

CRISPR-based gene-drives have been proposed for managing insect populations, including disease-transmitting mosquitoes, due to their ability to bias their inheritance toward super-Mendelian rates (>50%). Current technologies use a Cas9 that introduces DNA double-strand breaks into the opposing wild-type allele to replace it with a copy of the gene-drive allele via DNA homology-directed repair. However, the use of different Cas9 versions is unexplored, and alternative approaches could increase the available toolkit for gene-drive designs. Here, we report a gene-drive that relies on Cas9 nickases that generate staggered paired nicks in DNA to propagate the engineered gene-drive cassette. We show that …

Developing A Novel Place Preference Assay To Compare Drosophila Species Over Time, Martha M. Brinson

Honors Theses

Across phylogeny, integration of external factors, memory, and internal states of the organism dictate organismal behavior and mechanisms. The underlying genetic components can affect these behaviors such as in genomic changes arising from speciation. In this thesis, a new place preference assay was evaluated in the analysis and investigation of two species of Drosophila flies (D. melanogaster and D. simulans) to measure similarities and differences and their attraction to two different food substrates. Sleep and circadian measurements were also recorded during experimentation. The Drosophila Activity Monitor 5M (DAM5M) System and Sleep Circadian Analysis MATLAB Program (SCAMP) analysis were …

Headcase Regulates Growth In Response To Nutritional Status Downstream Of Insulin Signaling, Thomas George

Honors Scholar Theses

Cancer cells are notorious for growing in an unrestricted manner without regard for environmental cues. Recently, Li et al. (2019) discovered headcase (hdc) functions by binding to the mTORC1 complex in the mTOR signaling pathway and preventing further signaling. Interestingly, under nutrient restricted (NR) conditions, cells with mutated hdc proteins proliferated more than cells with normal functioning hdc. It is well known that insulin signaling is downregulated under NR conditions, so a potential signaling pathway with insulin, PI3K, PDK1, Akt, PTEN, and hdc was created as a way to explain the link between hdc function and nutritional status. A Drosophila …