Open Access. Powered by Scholars. Published by Universities.®

Life Sciences Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 16 of 16

Full-Text Articles in Life Sciences

Anteromedial Thalamus Gates The Selection & Stabilization Of Long-Term Memories, Andrew Toader Jan 2023

Anteromedial Thalamus Gates The Selection & Stabilization Of Long-Term Memories, Andrew Toader

Student Theses and Dissertations

The hippocampus is necessary for the initial encoding and recent storage of memories. Under the standard model of systems consolidation, it is thought that the memory trace eventually reorganizes from the hippocampus to a distributed cortical network, with the anterior cingulate cortex playing a central role in remote memory retrieval. However, little is known about the mechanisms responsible for coordinating this process. Additionally, the intermediate memory representations in the brain and the circuits that might gate and select memories for permanent storage remain unknown. To facilitate the longitudinal tracking of memory circuits in the brain, we first developed a novel …


Sensory Coding And Olfactory Integration In Caenorhabditis Elegans, May Dobosiewicz Jan 2019

Sensory Coding And Olfactory Integration In Caenorhabditis Elegans, May Dobosiewicz

Student Theses and Dissertations

Animals must sense their external environments to guide meaningful behavior. The nematode Caenorhabditis elegans, for example, uses volatile cues to navigate toward food from a distance. How does an animal integrate the olfactory information from its environment? Here, I ask how multiple sensory neurons drive and shape one interneuron’s activity. C. elegans senses several odors, including the bacterial metabolite diacetyl, using the AWA sensory neurons. AWA forms chemical and electrical synapses onto several interconnected interneurons, which contribute to chemotaxis toward attractive odors like diacetyl. One AWA target is the interneuron AIA, which is connected to AWA via a putative electrical …


Who Said That? Towards A Machine-Prediction-Based Approach To Tursiops Truncatus Whistle Localization And Attribution In A Reverberant Dolphinarium, Sean Fisher Woodward Jan 2019

Who Said That? Towards A Machine-Prediction-Based Approach To Tursiops Truncatus Whistle Localization And Attribution In A Reverberant Dolphinarium, Sean Fisher Woodward

Student Theses and Dissertations

Dolphin communication research is an active period of growth. Many researchers expect to find significant communicative capacity in dolphins given their known sociality and large and complex brains. Moreover, given dolphins’ known acoustic sensitivity, serving their well-studied echolocation ability, some researchers have speculated that dolphin communication is mediated in large part by a sophisticated “vocal” language. However, evidence supporting this belief is scarce. Among most dolphin species, a particular tonal class of call, termed the whistle, has been identified as socially important. In particular, for the common bottlenose dolphin, Tursiops truncatus – arguably the focal species of most dolphin cognitive …


A High-Throughput Approach To Uncover Novel Roles Of Apobec2, A Functional Orphan Of The Aid/Apobec Family, Linda Molla Jan 2018

A High-Throughput Approach To Uncover Novel Roles Of Apobec2, A Functional Orphan Of The Aid/Apobec Family, Linda Molla

Student Theses and Dissertations

APOBEC2 is a member of the AID/APOBEC cytidine deaminase family of proteins. Unlike most of AID/APOBEC, however, APOBEC2’s function remains elusive. Previous research has implicated APOBEC2 in diverse organisms and cellular processes such as muscle biology (in Mus musculus), regeneration (in Danio rerio), and development (in Xenopus laevis). APOBEC2 has also been implicated in cancer. However the enzymatic activity, substrate or physiological target(s) of APOBEC2 are unknown. For this thesis, I have combined Next Generation Sequencing (NGS) techniques with state-of-the-art molecular biology to determine the physiological targets of APOBEC2. Using a cell culture muscle differentiation system, and RNA sequencing (RNA-Seq) …


Density-Dependent Foraging In Caenorhabditis Elegans, Joshua Greene Jan 2017

Density-Dependent Foraging In Caenorhabditis Elegans, Joshua Greene

Student Theses and Dissertations

Game theory has long predicted that the density of competitors and their behaviors should affect foraging, and moreover suggests that multiple strategies can evolve and co-exist within a single species. I show that both of these predictions are met by foraging Caenorhabditis elegans. In Chapter 2, I show that animals alter their foraging behavior in response to population density, that certain pheromones induce this behavioral change, and that different wild isolates vary in response to the potent ascaroside icas#9. I use QTL mapping to find a major locus responsible for this variation, and map it to an icas#9 receptor, srx-43. …


Paleovirological Analyses Of Endogenous Retroviruses And Host Innate Immune Effectors, Daniel Blanco Melo Jan 2016

Paleovirological Analyses Of Endogenous Retroviruses And Host Innate Immune Effectors, Daniel Blanco Melo

Student Theses and Dissertations

About 8 and 10 percent of the human and mouse genomes, respectively, are comprised of sequences of retroviral origin. Occasional infection of germ line can lead to integrated retroviral genomes being vertically inherited as host alleles. During thousands to millions of years, some of these sequences acquired inactivating mutations and were fixed in ancestral populations by genetic drift, while others became fixed by providing an evolutionary advantage to the host. Those inherited proviruses are termed endogenous retroviruses (ERVs) and have been identified in a variety of animal species representing an extensive viral “fossil” record of past retroviral infections. With the …


Aversive Olfactory Imprinting In Caenorhabditis Elegans, Xin Jin Jan 2016

Aversive Olfactory Imprinting In Caenorhabditis Elegans, Xin Jin

Student Theses and Dissertations

Early memories are especially robust and enduring, among which the most evocative example is imprinting. Imprinting was first described in newly hatched geese that form a lasting attachment to the first moving object they see. As observed in many animal species, imprinting is a process in which a sensory cue presented early in animal’s life – a critical period – subsequently gains unique access to ecologically relevant behaviors. Little is known about the molecular and neural underpinnings of imprinting. I have used C. elegans as a model organism to study imprinting because of its compact and well characterized nervous system, …


A Reductionist Approach To Modeling Human Corticogenesis, Mohammad Zeeshan Ozair Jan 2015

A Reductionist Approach To Modeling Human Corticogenesis, Mohammad Zeeshan Ozair

Student Theses and Dissertations

The formation of the mammalian cerebral cortex is a complex multi-tiered process that involves three major milestones: 1) neural induction and folding of the neuroepithelium, 2) areal patterning and generation of various progenitor types, and 3) corticogenesis. Our current understanding of the molecular and cellular basis of cortical development comes largely from mouse studies due to the genetic tractability of this model system. However, as primate studies have shown, the primate brain is unique in terms of its progenitor and neuronal composition, cortical areas, scale, and gene expression. Limitations in the availability of non-human primate and human fetal material, the …


Transcriptome-Wide Characterization Of Apobec1-Catalyzed Rna Editing Events In Macrophages, Claire Ellen Hamilton Jan 2014

Transcriptome-Wide Characterization Of Apobec1-Catalyzed Rna Editing Events In Macrophages, Claire Ellen Hamilton

Student Theses and Dissertations

RNA editing refers to the process by which the sequence of RNA is altered through the insertion, deletion or modification of specific nucleotides. Editing of mRNA transcripts can increase the informational complexity encoded by the genome by producing alternative protein isoforms through specific posttranscriptional RNA editing events. Additionally, RNA editing in non-coding regions of mRNA transcripts has been shown to influence gene expression in a tissue-specific manner. In mammals, mRNA editing serves a diverse set of biological roles in neuronal function, host defense and lipid metabolism. The major mRNA editors acting in mammals include the adenosine deaminases acting on RNA …


Genetic Variation In Neurotransmitter Receptors Generates Behavioral Diversity, Andres Bendesky Jan 2012

Genetic Variation In Neurotransmitter Receptors Generates Behavioral Diversity, Andres Bendesky

Student Theses and Dissertations

Variation in behavior among individuals is both remarkable and of great significance to society. People differ in locomotor skills, in sleep patterns, in their willingness to take risks, and in how they relate to other people. Whereas diversity enriches society, extreme behavioral deviations can be pathological, so it is important to identify the causes of behavioral variability. It is clear that both the environment and genetics contribute to behavioral diversity in all animals, but the nature of the specific genes involved is only beginning to emerge. The nematode worm Caenorhabditis elegans is a good animal model to study the genetic …


The Impact Of Host Factors On Retroviral Evolution And The Identification Of A Novel Receptor That Was Used By An Ancient Primate Retrovirus, Steven J. Soll Jan 2010

The Impact Of Host Factors On Retroviral Evolution And The Identification Of A Novel Receptor That Was Used By An Ancient Primate Retrovirus, Steven J. Soll

Student Theses and Dissertations

The resurrection of inactive endogenous retroviruses allows us to learn about interactions between extinct pathogens and their hosts that occurred millions of years ago. Two of these paleoviruses, chimpanzee endogenous retrovirus 1 and 2 (CERV1 and CERV2), are relatives of modern murine leukemia viruses that are found in the genomes of a variety of old world primates, but are absent from the human genome. The nonexistence of human CERV1 and CERV2 homologues is peculiar given the numerous apparent cross-species transmissions that occurred between ancestors of old world monkeys, gorillas, and chimpanzees. It is possible that antiviral proteins were able to …


Reconstitution And Characterization Of Human Endogenous Retrovirus-K, Young Nam Lee Jan 2010

Reconstitution And Characterization Of Human Endogenous Retrovirus-K, Young Nam Lee

Student Theses and Dissertations

Retroviruses are a family of clinically significant and scientifically fascinating viruses that infect a wide array of organisms from all vertebrate classes. The two hallmark events in the life cycle of retroviruses are the reverse transcription of the single stranded RNA (ssRNA) genome generating a double stranded DNA (dsDNA) and the integration of this dsDNA into the host genome. Because integration is irreversible and the infected cells are usually difficult to target for elimination in the host, the infection is generally permanent. HIV-1, the most important and well-studied member of all retroviruses, is the causative agent of acquired immune deficiency …


Identification And Characterization Of Apobec1 Mrna Editing Targets: A Transcriptomics Approach, Brad Randall Rosenberg Jan 2010

Identification And Characterization Of Apobec1 Mrna Editing Targets: A Transcriptomics Approach, Brad Randall Rosenberg

Student Theses and Dissertations

RNA editing is generally defined as the alteration of an RNA sequence from that encoded by the genome through nucleotide insertion, deletion or modification. The Apolipoprotein B mRNA Editing Catalytic polypeptide 1 (APOBEC1) cytidine deaminase is an mRNA editing enzyme that modifies a specific cytidine in the apolipoprotein B (apoB) transcripts of small intestine enterocytes. APOBEC1-mediated cytidine to uridine editing generates an inframe stop codon and results in translation of a truncated apoB isoform with distinct functions in lipid transport. Other physiological mRNA targets of APOBEC1 editing have remained largely unknown. This thesis presents the development of an RNA-Seq method …


The Neural Circuitry Of Social Behavior In C. Elegans, Evan Z. Macosko Jan 2009

The Neural Circuitry Of Social Behavior In C. Elegans, Evan Z. Macosko

Student Theses and Dissertations

Most animal species, from simple invertebrates to complex mammals, require behavioral mechanisms to communicate with and respond to conspecifics, whether to mate, to assess predatory danger, or evaluate the nutritional quality of the surrounding environment. Understanding the molecular and cellular underpinnings of these social behaviors remains a central challenge in neurobiology. I used the nematode C. elegans as a model system to study the genetics and neural circuitry that underlie social behavior. First, I evaluated the behavioral responses of C. elegans to a nematode extract (deathmone), which served as a model for alarm pheromones in other animal species (chapter 2). …


A Search For The Counter-Immune Mechanisms Of Mycobacterium Tuberculosis, Meghan Alida Kirksey Jan 2007

A Search For The Counter-Immune Mechanisms Of Mycobacterium Tuberculosis, Meghan Alida Kirksey

Student Theses and Dissertations

Tuberculosis is characterized by dynamic interactions between M. tuberculosis (Mtb) and the human immune response. The cytokine IFN-γ triggers macrophage production of bactericidal nitric oxide by inducible nitric oxide synthase (NOS2) and is essential for mammalian control of Mtb infection. Mice lacking NOS2 are unable to control replication of Mtb and rapidly succumb to infection. The persistent nature of TB infection suggests that Mtb has evolved counter-immune mechanisms to survive in the face of NOS2 and other pathways downstream of IFN-γ. A differential signature-tagged transposon mutagenesis screen was conducted to identify mutants attenuated in NOS2-/- mice, but retaining virulence in …


Chronic Stress Effects On Prefrontal Cortical Structure And Function, Conor Liston Jan 2007

Chronic Stress Effects On Prefrontal Cortical Structure And Function, Conor Liston

Student Theses and Dissertations

Stressful life events have been implicated clinically in the pathogenesis of major depression, but the neural substrates that may account for this observation remain poorly understood. Attentional impairments symptomatic of depression are associated with structural and functional abnormalities in the prefrontal cortex. In three parallel rodent and human neuroimaging studies, this project assessed the effects of chronic stress on prefrontal cortical structure and function and the behavioral correlates of these changes. The first study used fMRI to elucidate the precise computational contributions of frontoparietal circuitry to attentional control in human subjects, using a task that could be adapted for rats. …