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Amygdala Mechanisms Involved in Chemosensory Communication
Title
Amygdala Mechanisms Involved in Chemosensory Communication.
Creator
Stroe, Ioana, Biological Science
Abstract/Description
The amygdala is an almond-shaped region of the brain present in many vertebrates such as human, hamsters and mice. The amygdala is composed of several parts, of which the following are most relevant to my research: the basolateral amygdala (BLA) and the posterior medial amygdala (MeP). The BLA functions in learning and shows increased activation after the mouse has learned a behavior. The lateral paracapsular nuclei of the intercalated nucleus (ICNlpcn) project inhibitory neurons into the BLA...
Show moreThe amygdala is an almond-shaped region of the brain present in many vertebrates such as human, hamsters and mice. The amygdala is composed of several parts, of which the following are most relevant to my research: the basolateral amygdala (BLA) and the posterior medial amygdala (MeP). The BLA functions in learning and shows increased activation after the mouse has learned a behavior. The lateral paracapsular nuclei of the intercalated nucleus (ICNlpcn) project inhibitory neurons into the BLA and mediate its activity. Dopamine has been shown to inhibit the lpcn group and therefore relieve inhibition of the BLA (disinhibition). Dopamine also acts directly in the BLA to increase activation. Therefore, if a mouse is conditioned to prefer a particular odor (in this case steer urine), dopamine injection will cause an increase in BLA activation after learning due to both disinhibition and direct excitatory response. The medial posterior amygdala in the mouse mostly responds to olfactory stimuli from the same species (conspecific stimuli). The MeP is also thought to be under control of another ICN group, the caudal ICN (ICNc). If the same inhibitory relationship is seen between ICNc and MeP, the dopamine injection may cause disinhibition in the MeP and therefore the conditioned steer urine stimulus may show increased activation in the MeP despite being a stimulus from another species (heterospecific stimulus). My experiment tests whether the ICNc has inhibitory control over the MeP, and whether dopamine will cause inhibition in the ICNc and therefore cause disinhibition in the MeP.
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Date Issued
2011
Identifier
FSU_migr_uhm-0040
Format
Thesis
Characterization of Maize Transgene-Reactivated Mutants
Title
Characterization of Maize Transgene-Reactivated Mutants.
Creator
Mills, Erica, Biological Science
Abstract/Description
Epigenetic gene regulation results from heritable changes in chromatin structure, DNA methylation, and/or histone modifications associated with different expression levels for endogenous genes and transgenes. The silent b1 transgene (Btg-s) can be used to study epigenetic gene regulation in maize. A forward genetics screen based on the reactivation of Btg-s was conducted using EMS mutagenized maize. Through this screen, several mutants reactivating the transgene, designated transgene...
Show moreEpigenetic gene regulation results from heritable changes in chromatin structure, DNA methylation, and/or histone modifications associated with different expression levels for endogenous genes and transgenes. The silent b1 transgene (Btg-s) can be used to study epigenetic gene regulation in maize. A forward genetics screen based on the reactivation of Btg-s was conducted using EMS mutagenized maize. Through this screen, several mutants reactivating the transgene, designated transgene reactivated (tgr), were identified. Published work demonstrates that mutations affecting proteins involved in the RNA-dependent DNA methylation pathway cause transgene reactivation. Such mutations result in characteristic phenotypes, such as a loss of DNA methylation, loss of siRNA accumulation, and loss of transcriptional silencing. To investigate Btg promoter methylation in the tgr mutants, bisulfite sequencing was performed on plants with silenced and reactivated transgenes from four lines of tgr mutants (tgr1-3,11). Results show that in three mutant lines, the promoter region had higher methylation levels in silenced plants compared to reactivated plants, while another mutant had similar levels of methylation in both phenotypes. For tgr2, siRNA levels were assayed and transcript abundance was evaluated for genes encoding proteins possibly involved in the methylation pathway. It was found that tgr2 showed no loss of siRNA production and no difference in transcript levels were observed between silenced and reactivated individuals for the genes evaluated. This work aided in characterizing the tgr mutants which are potentially strong tools for understanding epigenetic regulation of transgenes.
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Date Issued
2011
Identifier
FSU_migr_uhm-0028
Format
Thesis
Chromatin Structural Changes Linking Flavonoid Luteolin's Function to Genomic Targets
Title
Chromatin Structural Changes Linking Flavonoid Luteolin's Function to Genomic Targets.
Creator
Koerner, Joshua, Biological Science
Abstract/Description
Many non-inherited factors play a role in the epidemiology of cancer. Several studies have suggested that a dietary increase in fruits and vegetables containing compounds such as Luteolin, used in this study, would reduce the new instances of cancer by 20% and potentially prevent 200,000 cancer-related deaths annually. One hallmark of cancer is the reorganization of DNA inside the cell. Each cell in the human body contains approximately four meters of DNA organized into a compartment, the...
Show moreMany non-inherited factors play a role in the epidemiology of cancer. Several studies have suggested that a dietary increase in fruits and vegetables containing compounds such as Luteolin, used in this study, would reduce the new instances of cancer by 20% and potentially prevent 200,000 cancer-related deaths annually. One hallmark of cancer is the reorganization of DNA inside the cell. Each cell in the human body contains approximately four meters of DNA organized into a compartment, the nucleus, that is five one-hundredths of a millimeter. This almost unbelievable compaction is facilitated by the combination of negatively charged DNA with positively charged proteins to make a complex called chromatin. The organization of chromatin regulates access to DNA sequences. This project aimed to investigate factors that regulate the organization of chromatin, thereby regulating access to the genome. In this study we highlight five genomic locations where the structure of DNA changes in response to Luteolin treatment. We have potentially identified a new promoter region for the Abelson murine leukemia viral oncogene homolog 2, (ABL2) gene. Luteolin places a nucleosome in a transcriptionally active region of hydroxytryptamine receptor 2B (HTR2B) to inhibit the possible production of the gene product. Luteolin may be establishing transcriptional competence of cyclin-dependent kinase inhibitor 2A (CDKN2A) through regulation of chromatin structure around Sp1 binding sites in the promoter. Luteolin alters chromatin structure around the Sp1 binding sites in the promoter region of kisspeptin-1 (KiSS1), which could be a preliminary step to achieving transcriptional competence. Luteolin treatment alters the chromatin structure of the myelocytomatosis viral oncogene homolog (Myc) promoter in order to potentially re-establish steady state expression in a previously deregulated gene.
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Date Issued
2012
Identifier
FSU_migr_uhm-0079
Format
Thesis
Cost of Safety
Title
The Cost of Safety: Negotiating the Trade-Off between Safety and Growth.
Creator
Matechik, Christopher, Biological Science
Abstract/Description
To avoid the threat of predation, prey can alter their behavior such as moving from habitats where predation risk is high to those where it is low. However, such behaviors may involve a tradeoff if the low risk habitats are suboptimal feeding locations for the prey compared to the high risk ones. In seagrass, pinfish (Lagodon rhomboides) often move from low- to high-blade density patches in the presence of the predatory Gulf flounder (Paralichthys albigutta). However, restricted movements in...
Show moreTo avoid the threat of predation, prey can alter their behavior such as moving from habitats where predation risk is high to those where it is low. However, such behaviors may involve a tradeoff if the low risk habitats are suboptimal feeding locations for the prey compared to the high risk ones. In seagrass, pinfish (Lagodon rhomboides) often move from low- to high-blade density patches in the presence of the predatory Gulf flounder (Paralichthys albigutta). However, restricted movements in high-blade habitats may lead to reduced foraging efficiency and growth rates. I used a field experiment that ran for 28 days to examine this potential tradeoff between survival and growth. Neither predator presence nor seagrass blade density affected survival or growth in pinfish. However, after accounting for the loss of experimental replicates at lower grass-blade densities, the change in pinfish biomass was greater in the predator-present treatment compared to the controls, suggesting higher mortality, increased vigilance or both when flounder were present. Unfortunately, loss of experimental replicates and high variance in the measured responses hindered my ability to address the potential tradeoff, but suggestive results support further examination.
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Date Issued
2011
Identifier
FSU_migr_uhm-0025
Format
Thesis
Crosstalk between Chromatin Structure and DNA Methylation and the Regulation of DNA Templated Processes
Title
Crosstalk between Chromatin Structure and DNA Methylation and the Regulation of DNA Templated Processes.
Creator
Noori, Tarreq, Biological Science
Abstract/Description
Methylation of DNA is one of the earliest described epigenetic modifications. Hypermethylation is associated with gene silencing, while the inhibition of methylation is generally associated with reactivating silenced genes. The packaging of DNA in the nucleus into chromatin also plays a role in regulating gene expression. We sought to understand the crosstalk between changes in methylation status of the genome and changes in chromatin structure. 5-azacytidine (5-azaC), a potent DNA...
Show moreMethylation of DNA is one of the earliest described epigenetic modifications. Hypermethylation is associated with gene silencing, while the inhibition of methylation is generally associated with reactivating silenced genes. The packaging of DNA in the nucleus into chromatin also plays a role in regulating gene expression. We sought to understand the crosstalk between changes in methylation status of the genome and changes in chromatin structure. 5-azacytidine (5-azaC), a potent DNA methytransferase inhibitor, has recently generated interest as a potential anti-cancer drug, possibly functioning by reactivating silenced tumor suppressor genes. We treated the hematologic cancer cell lines U-937 and T-HP1 with 5-aza for varying lengths of time. We then harvested DNA for methylation studies, RNA for gene expression studies and chromatin for nuclease accessibility studies. The chromatin accessibility was further measured at two different levels of resolution; the domain level (10s of kb) and nucleosome position (10s of bp). This was achieved using an innovative DNA microarray assay. Results were analyzed to correlate changes in chromatin structure with changes in methylation and gene expression. We have identified that the class II, major histocompatibility complex, transactivator (CIITA) shows chromatin structural changes. The results provide a model for understanding the regulatory chromatin structure involved in the immune response.
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Date Issued
2011
Identifier
FSU_migr_uhm-0032
Format
Thesis
Exploring the Function of 14-3-3 Proteins in Neurodegenerative Disease
Title
Exploring the Function of 14-3-3 Proteins in Neurodegenerative Disease.
Creator
Vogt, Peggy, Biological Science
Abstract/Description
The two pathological hallmarks of Parkinson's are neurodegeneration in the substantia nigra parc compacta and the presence of Lewy bodies in the surviving neurons. Recent evidence indicates that Lewy bodies share biochemical and morphological similarities with aggresomes, a large juxtanuclear aggregate. In previous studies, we observed that 14-3-3 proteins promote the aggresome formation of α-Synuclein, the main component of Lewy bodies. In this study, we determined 14-3-3 to have a...
Show moreThe two pathological hallmarks of Parkinson's are neurodegeneration in the substantia nigra parc compacta and the presence of Lewy bodies in the surviving neurons. Recent evidence indicates that Lewy bodies share biochemical and morphological similarities with aggresomes, a large juxtanuclear aggregate. In previous studies, we observed that 14-3-3 proteins promote the aggresome formation of α-Synuclein, the main component of Lewy bodies. In this study, we determined 14-3-3 to have a generalized aggresome promoting function by examining two known aggregation-prone proteins, including a mutant form of CFTR and the GFP-250 protein. To assess the isoform specificity of 14-3-3 proteins in this process, we compared the extent of increase in aggresome formation promoted by overexpression of two different 14-3-3 isoforms. Furthermore, we utilized two different mutants to demonstrate that dimerization of 14-3-3 may not be required for its function in the aggresome formation cascade. Taken together, our data indicate that 14-3-3 proteins may play essential critical role in the aggresome formation process. The discovery of the mechanism by which 14-3-3 participates in the aggresome formation cascade may help us to understand pathogenesis of neurodegenerative diseases, such as Parkinson's disease.
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Date Issued
2011
Identifier
FSU_migr_uhm-0042
Format
Thesis
Hallmark Pathology of Temporal Lobe Epilepsy
Title
Hallmark Pathology of Temporal Lobe Epilepsy: Loss of Layer III Pyramidal Neurons in the Entorhinal Cortex and its Relation to Distribution of NMDA Receptor Subunits.
Creator
Richardson, Max, Biological Science
Abstract/Description
Neuronal loss in Layer III of the medial entorhinal cortex (MEA) is a characteristic phenomenon associated with Temporal Lobe Epilepsy. The immediately adjacent lateral entorhinal cortex (LEA) does not exhibit such loss. The current study uses indirect immunofluorescence assays in the third layer of both the medial and lateral entorhinal cortex to detect differences in protein expression of the most prevalent N-methyl-D-aspartate receptor (NMDAR) subunit isoforms in the adult cortex: the...
Show moreNeuronal loss in Layer III of the medial entorhinal cortex (MEA) is a characteristic phenomenon associated with Temporal Lobe Epilepsy. The immediately adjacent lateral entorhinal cortex (LEA) does not exhibit such loss. The current study uses indirect immunofluorescence assays in the third layer of both the medial and lateral entorhinal cortex to detect differences in protein expression of the most prevalent N-methyl-D-aspartate receptor (NMDAR) subunit isoforms in the adult cortex: the GluN1, GluN2A and GluN2B subunits. The latter two subunits confer varying levels of Ca2+ permeability and ostensibly the potential for excitotoxicity that may lead to characteristic loss of this particular population of neurons. We find that the level of GluN1 protein expression in the MEA and LEA is similar, suggesting that the number of NMDARs in the MEA and LEA is also similar, and that both GluN2A and GluN2B expression is higher in the MEA than in the LEA. These findings taken together may suggest a difference in subunit distribution and/or stoichiometry of NMDA receptors between the third layer of the MEA and LEA.
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Date Issued
2012
Identifier
FSU_migr_uhm-0061
Format
Thesis
Histone Deacetylase Inhibitors Prevent Nucleosome Redistribution at Transcription Start Sites
Title
Histone Deacetylase Inhibitors Prevent Nucleosome Redistribution at Transcription Start Sites.
Creator
Pickeral, Crystal, Biological Science
Date Issued
2011
Identifier
FSU_migr_uhm-0034
Format
Thesis
Phylogeographic Patterns in the Eastern Diamondback Rattlesnake (Crotalus adamanteus)
Title
Phylogeographic Patterns in the Eastern Diamondback Rattlesnake (Crotalus adamanteus).
Creator
Aronow, Karalyn, Biological Science
Abstract/Description
The aim of this project was to analyze relationships among populations of Crotalus adamanteus (Eastern Diamondback Rattlesnake) and to compare phylogeographic patterns across different classes of genes. The objective was to determine the effect of selective pressures on the detection of barriers to gene flow. For example, venom genes are under strong positive selection and allow an analysis of the rate of allele exchange in a gene that directly affects the fitness of an individual. This...
Show moreThe aim of this project was to analyze relationships among populations of Crotalus adamanteus (Eastern Diamondback Rattlesnake) and to compare phylogeographic patterns across different classes of genes. The objective was to determine the effect of selective pressures on the detection of barriers to gene flow. For example, venom genes are under strong positive selection and allow an analysis of the rate of allele exchange in a gene that directly affects the fitness of an individual. This selection might drive alleles through phylogeographic barriers that limit the spread of neutral alleles. The relationship between nontoxin genes and fitness is not as clear and can be difficult to establish. However, most variation in these genes is neutral and determined by stochastic events. The type of selection on a gene will affect the phylogeographic pattern displayed. Prior phylogeographic studies have used either neutral markers (e.g., microsatellites) or genes not directly involved in specific adaptations (e.g., mitochondrial genes). One venom gene, two mitochondrial genes, one nuclear gene, and one pseudogene were compared for patterns of adaptation and the presence of geographic barriers to gene flow. This novel approach to studying gene flow could have an impact on defining taxonomic groups and conservation efforts, as well as serve as a guide for choosing appropriate genetic markers for other species. In the venom gene that was analyzed, it appeared the high level of selection led to alleles being driven across the barriers to gene flow of alleles under neutral selection.
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Date Issued
2011
Identifier
FSU_migr_uhm-0002
Format
Thesis
Rescue of a Chlamdydomonas Reinhardtii Mutant
Title
Rescue of a Chlamdydomonas Reinhardtii Mutant.
Creator
Crumbley, Christine, Biological Science
Abstract/Description
This research focuses on the signal transduction pathway involved in acid-induced deflagellation in the green algae Chlamydomonas reinhardtii. A wild type copy of the 2L15 gene will be amplified and used to create a plasmid. This plasmid will contain a wild type copy of the nitrate reductase gene of Chlamydomonas reinhardtii, which will serve as a selectable marker, as well as the 2L15 gene. The plasmid will be used to transform Chlamydomonas reinhardtii mutants with the hope of rescuing the...
Show moreThis research focuses on the signal transduction pathway involved in acid-induced deflagellation in the green algae Chlamydomonas reinhardtii. A wild type copy of the 2L15 gene will be amplified and used to create a plasmid. This plasmid will contain a wild type copy of the nitrate reductase gene of Chlamydomonas reinhardtii, which will serve as a selectable marker, as well as the 2L15 gene. The plasmid will be used to transform Chlamydomonas reinhardtii mutants with the hope of rescuing the mutant phenotype.
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Date Issued
2007
Identifier
FSU_migr_uhm-0044
Format
Thesis