Life Sciences Commons^™

The Biobehavioral Effects Of Embryonic Exposure To Neural Inflammation And Oxidative Stress In Zebrafish, Dalton J. Anderson

Honors College Theses

The purpose of this research is to improve understanding of the neurodevelopmental effects of embryonic exposure to elevated inflammation and oxidative stress induced by the antipyretic drug acetaminophen (APAP). Our study was the first to examine the interactive effects of APAP and inflammation in zebrafish embryos and how the treatments affect brain development and larval behavior. Experimental groups of zebrafish larvae were exposed to lipopolysaccharide (LPS) to induce inflammation, APAP, or LPS + APAP and larval behavior was analyzed using Ethovision automated behavioral tracking software. We also measured changes in whole-brain Glycogen Synthase Kinase 3 Beta (GSK3B) and GSK3B phosphorylation, …

Zebrafish Electroretinogram Responses, Brooke Campbell

Williams Honors College, Honors Research Projects

The goal of this project is to be able to streamline a protocol for conducting ERGs on zebrafish from mice ERG protocol already present in Dr. Renna’s lab. The objective is to create a protocol specifically for zebrafish and to eliminate any issues that occur when transiting from a mice ERG protocol to a zebrafish ERG protocol and to obtain a light response from zebrafish retinae in differing light intensities. Dr. Renna’s lab has designed an Ex Vivo ERG system with less electrical interference creating defined electrical responses from mouse retina. The setup allows for continual perfusion of the retinal …

Neurogenetic Function Of Host Cell Factor-1, Victoria Lynn Castro

Open Access Theses & Dissertations

Neural precursor cells (NPCs) are the stem-like cells of the developing brain. These cells differentiate into the differentiated cell types of the central nervous system. If disruption occurs in the number of total NPCs formed or their survival, various disorders including learning disabilities, behavioral problems, or epilepsy can occur. This dissertation describes how the HCFC1 gene controls the proliferation and differentiation of NPCs. HCFC1 encodes for a transcriptional co-factor that regulates the growth and metabolism of stem cells, including NPCs. Mutations in HCFC1 cause cblX syndrome, a neural developmental disorder that affects the nervous system and causes microcephaly, epilepsy, and …

Is The Area Postrema Resistant To The Anesthetic Effects Of Ms-222?, Austin T. Csiszar

Cal Poly Humboldt theses and projects

MS-222 is a common fish anesthetic that dampens neural activity by inhibiting neuronal voltage-gated sodium channels (Na_v) required for action potentials. Previous experiments conducted by our lab’s primary investigator using fluorescence calcium imaging in zebrafish neurons resulted in the observation that neurons in the area postrema (AP), a circumventricular organ located in the dorsal hindbrain, displayed prominent fluorescence intensity during MS-222 induced sedation. I used the genetically encoded calcium indicator GCaMP6s to conduct fluorescence calcium imaging with the goal of recording neural activity in the larval zebrafish area postrema and optic tectum to compare the anesthetic effects of …

Mapping Auditory And Vestibular Response Neurons In The Optic Tectum Of Larval Zebrafish, Erika Marks, Arminda Suli

Undergraduate Honors Theses

Cellular mapping of the sensory receptive fields of brain structures is a critical step in understanding function and dysfunction in development. Deficits in the ability to receive, process and integrate the senses leads to difficulties recognizing and responding appropriately to stimuli. To understand how the senses are integrated, it is first necessary to map the neurons receptive to inputs from individual senses. The optic tectum of zebrafish is a structure known for its homology to the superior colliculus of mammals and is a center of multisensory integration – including visual, auditory, and somatosensory stimuli. However, the microcircuitry of this important …

Examining Development And Function Of Pretectal Visual Neural Circuits In Gs Homeobox 1 Mutant Zebrafish, Alexandra Rose Schmidt

Graduate Theses, Dissertations, and Problem Reports

Brain development requires a coordinated genetic code to regulate initial cell identity determination, migration, and connectivity, to establish function of neural circuits. Independent neural circuits underlie our ability to produce both complex and innate behavioral responses to sensory stimuli that are often conserved across vertebrate organisms. Sensory processing disruptions are associated with several neurodevelopmental disorders (NDDs). Therefore, gene mutations altering neurodevelopment can lead to changes influencing structure and function of individual neural circuits, causing behavioral deviations in sensory responsiveness. Crucial gene networks that define functional properties of sensory domains are often explored using non-mammalian vertebrate models, such as the zebrafish. …

Does Bisphenol-A, An Estrogen-Like Environmental Toxin, Disrupt Expression Of The Neuronal Chloride Exporter Protein During Early Brain Development?, Mayra S. Mendez

Cal Poly Humboldt theses and projects

Bisphenol A (BPA), a manufactured compound found in consumer products, is known to adversely affect early brain development by disrupting normal estrogen signaling. Recently, BPA was reported to suppress expression of a gene encoding the neuron-specific chloride ion transporter, KCC2. Human and animal studies show suppressing KCC2 can cause neuronal and behavioral hyperactivity. Therefore, some adverse effects of BPA may be due to KCC2 suppression and consequent neuronal hyperactivity. This study aimed to determine whether BPA exposure during brain development alters KCC2 expression. A secondary purpose was to evaluate whether a new transgenic zebrafish line, KCC2:mCitrine,could be used to track …

Use Of A Zebrafish Model To Identify Anticonvulsant Properties Of Cannabinoid And Terpenoid Extracts And Mixtures, Courtney Murr

LSU Master's Theses

Epilepsy is a complex group of neurological disorders affecting approximately 65 million people worldwide. Animal models reveal the activation of cannabinoid receptor 1 and cannabinoid receptor 2 reduces the severity of seizures associated with epilepsy. Trials of phytocannabinoids in mammals demonstrate their efficacy of reducing the severity of epileptic seizures. Numerous terpenoid compounds are present in Cannabis plants but most have yet to be clinically investigated. The goal of this research was to use zebrafish (Danio rerio) to identify the potential anticonvulsive properties of phytocannabinoid and terpenoid compounds. During acute cannabinoid exposures, 7-days-post-fertilization (7 dpf) zebrafish larvae were …

The Influence Of Autism Linked Gene Topoisomerase 3b (Top3b) On Neural Development In Zebrafish, Sydney Doolittle

Honors College Theses

Autism Spectrum Disorder is a class of developmental disabilities characterized by a spectrum of social, communication, and behavioral impairments in affected individuals. Studies have shown these defects stem from abnormal brain development during critical periods during early development. The underlying genetic cause of these impairments is not well understood but is believed to be a combination of a complex pairing of genetic and environmental factors. One of the genetic factors that has been recognized to influence the phenotypic symptoms of ASD is the enzyme topoisomerase 3β (top3β.) Topoisomerases are responsible for the prevention of supercoiling during DNA replication. Top3β is …

Estrogen Disruption Of Hypothalamic Neural Activity, Princess Dickson

Cal Poly Humboldt theses and projects

The brain is highly dependent on the endocrine system for proper neurodevelopment, as it plays a key role in many biological processes. Bisphenol A is a chemical found in plastics that has the potential to mimic the effects of Estrogen in the body, at least weakly. People interact with plastic that contains BPA regularly, and people are at risk for exposure even before being born. The abundance of BPA, along with other exogenous estrogens, makes examining the relationship between early exposure and changes in brain activity imperative. The current study aims to establish a relationship between disrupted estrogen function and …

Using Zebrafish To Elucidate The Expression And Gene Regulatory Network Of The Genomic Screen Homeobox Transcription Factors And Bring Innovative Science Learning Experiences To West Virginia, Rebecca Ann Coltogirone

Graduate Theses, Dissertations, and Problem Reports

Central nervous system (CNS) development requires a code of regionally expressed transcription factors that impart initial neuronal cell identity, connectivity, and function. The absence of a transcription factor code would eliminate the neurodevelopmental logic producing diverse cell types in the CNS. Furthermore, early disruptions in transcription factor expression can affect later connectivity and function of neuronal circuits mediating sensory processing, defects in which are often observed as comorbid with various neurodevelopmental disorders (NDDs). Characterizing transcription factor expression and function is therefore an essential step in discerning the molecular mechanisms underlying human NDDs. genomic screen homeobox 1 and 2 (gsx1 …

The Effects Of Dorsal Lateral Telencephalon Lesions On Zebrafish Social Behaviour, Hailey Katzman

Theses and Dissertations (Comprehensive)

Zebrafish are extremely social and aggregate in groups to form shoals. This social behaviour has been studied in the wild and in a laboratory setting, yet the mechanisms underlying the behaviour are unknown. There is evidence to suggest that the dorsal lateral telencephalon might play a role in shaping shoaling behaviour, being involved in modulating social behaviours and social reward associated with shoaling. In the current thesis, I adapted and combined several existing methods for performing lesions on the dorsal lateral telencephalon to create my own method to measure the role of the dorsal lateral telencephalon in social reward and …

Non-Invasive Method For Leptin Supplementation In Zebrafish (Danio Rerio), Regan Mcnamara

Williams Honors College, Honors Research Projects

I tested the hypothesis that recombinant leptin protein can be introduced to zebrafish in vivo through non-invasive soaking in a solution containing the protein. One way to study various molecules’ effects in vivo is through intraperitoneal or intracerebroventricular injections during the embryonic or larval stage, which is invasive, difficult to administer, and can have a high mortality rate. 48 hours post fertilization (hpf) zebrafish were soaked in a His-tagged recombinant leptin protein solution at 10 nM and 100 nM concentrations (produced by Genscript). After soaking, zebrafish larvae were washed extensively to remove all recombinant protein on their exterior before homogenization. …

Neurodevelopmental Roles Of Semaphorin6a/Plexina2 Signaling In Zebrafish, Sarah Elizabeth Emerson

Graduate College Dissertations and Theses

ABSTRACT

A multitude of complex cellular changes are required throughout development in order for a single cell to transform into a fully functioning organism. Cellular events including proliferation, migration, and differentiation have to be carefully controlled in order for development to proceed correctly. In order to study such dynamic processes, in vivo models are often utilized. Using the zebrafish (Danio rerio) as a model system, we have investigated the role of an axon guidance signaling pair, Semaphorin6A (Sema6A) and PlexinA2 (PlxnA2), in neurodevelopment.

A previous investigation into the developmental expression patterns of sema6A and plxnA2 in zebrafish, revealed overlapping expression …

Biochemical And Functional Characterization Of Semaphorin6a-Plexina Signaling In Zebrafish Eye Development, Riley St. Clair

Graduate College Dissertations and Theses

During embryonic development, cells respond to extracellular signals to establish proper tissue organization. Semaphorins (Semas) are a large class of secreted and transmembrane proteins that signal through Plexin (Plxn) receptors to guide migrating cells to their correct position and thus play critical roles in the development of various tissues including the nervous and cardiovascular systems. We have previously shown that Sema6A-PlxnA2 signaling is essential for visual system development, as decreasing endogenous Sema6A or PlxnA2 in zebrafish results in decreased cohesion of the early eye field, impaired retinal lamination, and smaller eye size. However, the molecular mechanisms governing these phenotypes are …

Fast Objective Coupled Planar Illumination Microscopy, Cody Jonathan Greer

Arts & Sciences Electronic Theses and Dissertations

Among optical imaging techniques light sheet fluorescence microscopy stands out as one of the most attractive for capturing high-speed biological dynamics unfolding in three dimensions. The technique is potentially millions of times faster than point-scanning techniques such as two-photon microscopy. This potential is especially poignant for neuroscience applications due to the fact that interactions between neurons transpire over mere milliseconds within tissue volumes spanning hundreds of cubic microns. However current-generation light sheet microscopes are limited by volume scanning rate and/or camera frame rate. We begin by reviewing the optical principles underlying light sheet fluorescence microscopy and the origin of these …

The Role Of Actr10 In Nervous System Development And Disease, Amy Herbert

Arts & Sciences Electronic Theses and Dissertations

The vertebrate nervous system requires myelinating glia for the fast propagation of action potentials, as well as for vital trophic support to axons. Myelinating glia produce myelin, which is a lipid-rich, multi-lamellar sheath that surrounds axons and allows for rapid electrical signaling. In the central nervous system (CNS), myelin is produced by oligodendrocytes, while in the peripheral nervous system (PNS), Schwann cells perform this function. Although glia have historically been understudied compared to neurons, recent research has uncovered critical roles for glia in nervous system development and disease. Disruption to myelin or to the glial cells that generate myelin can …

Effects Of Daily Forced Exercise On Anxiety Of Zebrafish (Danio Rerio) Living In Impoverished Environments, Meagan Collins

Undergraduate Theses and Capstone Projects

The purpose of this research was to investigate the effects of forced exercise on anxiogenic behavior in Danio rerio living in different environmental conditions. To study this relationship, zebrafish were introduced to the following housing environments for several weeks. Fish in Group 1 were exposed to brown gravel and green, plastic plants (enriched environment), and fish in Group 2 were exposed to no brown gravel and no green, plastic plants (impoverished, structurally-barren environment). Fish from both housing environments were randomly assigned to be exposed to exercise or no exercise (control). Fish in the exercise group were forced to swim against …

Test Of Bpa's Estrogenic Effects On Brain Aromatase Expression, Neural Activity, And Locomotive Behavior In Zebrafish Larvae, Ryan J. Mcauley

Cal Poly Humboldt theses and projects

Bisphenol A (BPA) is a well-known endocrine disrupting chemical that mimics the effects of estrogens. Aromatase B (Cyp19a1b) is a brain-specific enzyme that converts testosterone to estrogen and is highly upregulated in response to estrogen receptor activation localized to radial glial cells. During embryonic zebrafish development, there is a small window of time denoted by an increase in neurogenesis and estrogen receptor activity. Previous studies have demonstrated that a low dose BPA exposure (0.1µM) during this window causes hyperlocomotion in larval zebrafish, yet no further explanation for this behavior change has been described. The purpose of this study was to …

Genetic And Genomic Dissections Of Myelinating Glial Cell Development, Breanne Leigh Harty

Arts & Sciences Electronic Theses and Dissertations

Myelin is a multilamellar sheath made by specialized glial cells that iteratively spiral and compact their plasma membranes around axon segments. In vertebrate nervous systems, myelination facilitates rapid action propagation and provides trophic support critical for neuronal survival. In the central nervous system (CNS), oligodendrocytes (OLs) extend many processes to simultaneously ensheath multiple axons, while in the peripheral nervous system (PNS), myelinating Schwann cells (SCs) pair 1:1 with a single axon segment. Elaboration of the myelin sheath is one of the most exquisite and complex examples of massive coordinated cellular shape changes in the vertebrate nervous system. Furthermore, the importance …

Anxiety-Like Behaviors And C-Fos Expression In Adult Zebrafish: Effects Of Housing Conditions, Alcohol And Caffeine, Adam Douglas Collier

Dissertations

Alcohol abuse is the third largest risk factor for disease world, responsible for an estimated 3.3 million deaths each year. The concomitant ingestion of alcohol and caffeine is hypothesized to increase risk factors associated with alcohol use alone by reducing subjective effects of intoxication. The zebrafish (Danio rerio) has recently garnered attention from researchers as an effective pre-clinical in-vivo animal model in behavioral pharmacology research, largely due to small size, low-cost and ease of drug delivery. A number of studies have reported the effects of alcohol and caffeine on zebrafish behavior at a variety of doses. However, the …

Effects Of Global Dna Methylation Changes On Neurobehavior In Zebrafish, Matthew Christopher Pickens

Theses and Dissertations

A number of environmental neurotoxicants modulate DNA methylation, but its influence on neurobehavior remains unclear. The laboratory has established that low-level developmental methylmercury exposure induces neurobehavioral deficits; the current results demonstrate that it also induces global DNA hypomethylation. DNA methyltransferase 1-mutant zebrafish (exhibit ~70% reduction in enzymatic activity) were used to assess the role of DNA hypomethylation on behavior. Several neurobehavioral assays including the C-start escape, circadian rhythm, basic locomotion and visual-motor response (VMR) were also performed. There was a significant difference in VMR between the wild type and mutant animals. Other behavior assays revealed no significant difference, primarily due …

Dual Functions For Insulinoma-Associated 1 In Retinal Development, Marie A. Forbes-Osborne

Theses and Dissertations--Biology

Proper visual system function requires tightly controlled proliferation of a pool of relatively homogeneous retinal progenitor cells, followed by the stepwise specification and differentiation of multiple distinct cell types. These retinal cells, both neuronal and glial, must be generated in the correct numbers, and the correct laminar location to permit the formation of synaptic connections between individual cell types. After synapses are made, constant signaling is required as part of normal retinal function, and to maintain cellular identity and connectivity. These processes rely on both extrinsic and intrinsic signaling, with regulation of gene expression by cascades of transcription factors having …

A Structure/Function Analysis Of Nhsl1b In Facial Branchiomotor Neurons, John Ojumu

Theses and Dissertations

The goal of this study was to identify critical regions of a novel gene, Nance-Horan syndrome-like 1b (nhsl1b). It was previously discovered that C-terminal truncation of the Nhsl1b protein in nhsl1b mutants resulted in a loss of migration in the facial motor neurons of the hindbrain (Walsh et al. 2011). As nhsl1b expresses many isoforms, multiple targets were investigated in order to determine which transcript bears the largest impact on the motor neurons. Using confocal microscopy to observe immunostained embryos, we examined a mutation in an nhsl1b transcript that encodes a WHD, a domain that is known to …

Gene Regulatory Pathways Driving Central Nervous System Regeneration In Zebrafish, Ishwariya Venkatesh

Theses and Dissertations

Damage to the central nervous system (CNS) circuitry of adult mammals results in permanent disability. In contrast, the ability to regenerate damaged CNS nerves and achieve functional recovery occurs naturally in fish. The ability of fish to successfully regrow damaged CNS nerves is in part a consequence of their ability to re-express key neuronal growth-associated genes/proteins in response to CNS injury. On such protein is Growth-Associated Protein-43 (Gap43), a protein which is highly enriched in axonal growth cones during CNS development and regeneration. Experiments conducted in mammals have demonstrated that ectopic expression of GAP-43 improves axonal re-growth after injury. Using …

The Role Of Gap-43 Phosphorylation In Axon Behavior In The Developing Zebrafish Visual System, Jennifer Forecki

Theses and Dissertations

Developing neurons extend processes to specific targets and establish connections that are essential for future function of the nervous system. One of these processes, the axon, has a motile tip called a growth cone that rearranges its membrane-associated actin cytoskeleton to turn toward or away from environmental guidance cues. Growth associated protein 43 (GAP-43) is one of the most abundant proteins associated with axonal growth cone membranes and is known to modulate the formation and stability of the actin cytoskeleton during axon guidance. Protein kinase C (PKC)-mediated phosphorylation of GAP-43 on serine 42 regulates its interactions with actin. Phosphorylated GAP-43 …