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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

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

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

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

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

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

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

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

Aronow, Karalyn (1)	+ -
Crumbley, Christine (1)	+ -
Matechik, Christopher (1)	+ -
Mills, Erica (1)	+ -
Noori, Tarreq (1)	+ -

Pickeral, Crystal (1)	+ -
Stroe, Ioana (1)	+ -
Vogt, Peggy (1)	+ -

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