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Iron Acquisition In Rhodococcus Erythropolis Strain Igts8: Characterization Of A Mutant Strain That Over Produces Siderophore., Melanie Anne Pratt

Electronic Theses and Dissertations

Iron is an essential nutrient for most bacteria because enzymes like nitrate reductase and cytochromes use it as a cofactor. However, in most aerobic, neutral pH environments, iron is essentially insoluble and not easily available for bacteria to use. Many bacteria respond to this problem by releasing small organic compounds called siderophores that bind and effectively solubilize iron so that it can be transported into the cell for growth. The focus of this study was to learn more about the iron acquisition and especially the transport of iron by the soil bacterium Rhodococcus erythropolis. To fulfill this aim, mutant …

Elucidating The Role Of The Α7 Nicotinic Receptor In The Etiology Of Schizophrenia., Michelle Johnson Chandley

Electronic Theses and Dissertations

The α7 subunit of the nicotinic receptor, a ligand gated ion channel with an affinity for nicotine, has long been implicated in the pathophysiology of schizophrenia due to the extremely high rate of smoking within the patient population. However, the exact role of the receptor has never fully been determined. In the following studies, various functions the receptor may assume in disease state are evaluated. There is a strong relationship between the immune system and schizophrenia, with the α7 subunit possibly serving as the link between the two. One of the following studies looks at the possibility of the receptor …

Herpes Simplex Virus Glycoprotein D/Host Cell Surface Interaction Stimulates Chlamydia Trachomatis Persistence Via A Novel Pathway., Jennifer Vanover

Electronic Theses and Dissertations

When presented with certain unfavorable environmental conditions, C. trachomatis reticulate bodies (RBs) enter into a viable, yet noncultivable state called persistence. Two hallmarks of persistent chlamydiae are swollen, aberrantly shaped RBs, as viewed by transmission electron microscopy and a decrease in infectious progeny. Several models of chlamydial persistence have been described, including interferon-γ (IFN-γ), IFN-α, IFN-β, and tumor necrosis factor-α-exposure and nutrient deprivation. Previously, we established an in vitro co-infection model of two of the most common sexually transmitted pathogens in the United States, C. trachomatis and Herpes Simplex Virus-2 (HSV). Data from this tissue culture model indicate that: i) …

Urinary Excretion Of (1-3)-Beta-D-Glucans., Debra K. Head

Electronic Theses and Dissertations

(1→3)-β-D-Glucans are carbohydrate polymers that are present in the cell wall of various fungi and bacteria; they are pathogen associated molecular patterns that circulate during infection and modulate immunity. Our laboratory has previously established the pharmacokinetics of intravenously and orally administered glucans; the present studies investigated the renal excretion of (1→3)-β-D-glucans following intravenous and oral administration. Three fluorescently-labeled glucans were administered to adult male rats in the presence or absence of toxic challenge. Urine specimens were collected and analyzed by fluorescence spectroscopy, size-exclusion chromatography and GPC/MALLS. 71 ± 3% of fluorescence remained in the >5K MWCO fraction; this fraction showed …

Study Of Basic Wood Decay Mechanisms And Their Biotechnological Applications, Yuhui Qian

Electronic Theses and Dissertations

The overall objective of this thesis was to gain further understanding of the non-enzymatic mechanisms involved in brown-rot wood decay, especially the role of pH, oxalic acid, and low molecular catecholate compounds on the dissolution and reduction of iron, and the formation of reactive oxygen species. Another focus of this study will be the potential application of a biomimetic free radical generating system inspired from fungi wood decay process, especially the non-enzymatic mechanism. The possible pathways of iron uptake and iron redox cycling in non-enzymatic brown-rot decay were investigated in this study. UV-Vis spectroscopy and HPLC were employed to study …

An Assessment Of Alternative Feed Ingredients In Practical Diets For Florida Pompano (Trachinotus Carolinus) Held In Low Salinity Recirculating Systems, Terhea Nichole Williams

Electronic Theses and Dissertations

The identification of alternative protein sources for partial or whole replacement of fishmeal (FM) is a priority in the development of suitable, low cost feed formulations for the Florida pompano (Trachinotus carolinus). To evaluate alternative feed ingredients for the potential replacement of FM in diets fed to juvenile pompano, a series of four experiments were conducted. The objectives of Experiments 1 and 2 were to determine the apparent digestibility of crude protein (ADCP), energy (ADE), and apparent amino acid availability (AAAA) of three plant based ingredients (soybean meal (SBM), soy protein isolate (SPI), corn gluten meal (CGM)) and three by-product …

Polymer Supported Optical Biosensors, Ignacio Joseph Garcia

Electronic Theses and Dissertations

The use of various polymer supports adhering phospholipid multibilayers to an internal reflection element have been investigated. The polymer supports studied range from polystyrene (PS), and 100 nm wide PS nanospheres to triethylaminated poly(vinyl benzyl chloride) (PVBC). The PS nanospheres showed the most promise as an adhesion layer since they appear to be the most robust with repeated washings. They also appear to stabilize their adjacent phospholipid multibilayer by increasing the lipid melting temperature. The triethylaminated DVBC also provided an increase of lipid melting temperature, but not quite to the same degree as the PS nanospheres. The cooperativity of such …

Characterization Of The Pathway Leading To The Synthesis Of Salicylic Acid In Plants Resisting Pathogen Infection., Alexander Eddo

Electronic Theses and Dissertations

Salicylic acid is a plant hormone that accumulates with plant-pathogen interaction. This accumulation corresponds to the plant being resistant to infection and without it the plant is susceptible. In this study, primers of genes involved in the normal synthesis of SA were used in RT-PCR to compare gene expression levels in susceptible and resistant plants challenged with tobacco mosaic virus. Because SA synthesis shares chorismate as a common substrate with the synthesis of aromatic amino acids, HPLC was used to determine whether the increase in SA could be attributed to a decrease in amino acid levels. The results suggest that …

Amphetamine Sensitization And In Vivo Microdialysis Of The Nucleus Accumbens Core Of Adult Male And Female Rats D2-Primed As Neonates., Zackary Adam Cope

Electronic Theses and Dissertations

Neonatal administration of quinpirole produces significant increases in D₂ receptor sensitivity that persists into adulthood. This phenomenon, known as D₂ receptor priming, is consistent with pathology in schizophrenia. Rats were administered quinpirole or saline postnatally and raised to adulthood. In adulthood, rats were administered d-amphetamine sulfate or saline every other day and were placed in a locomotor arena where activity was measured over 7 trials. Results showed that D₂-primed rats receiving amphetamine were higher in locomotor activity across all days of testing compared to other groups. This effect was more prominent in males than in females. …

Gene Expression And Phenotype Response Of Drosophila Melanogaster To Selection., Kenneth W. Mcdonald

Electronic Theses and Dissertations

The evolution of phenotypic plasticity is currently a topic of paramount interest in a diverse field of sub-disciplines. Salience is placed by all fields in describing the interaction of selection and phenotypic plasticity and the consequence of this interaction more broadly on evolution. Lacking in the discussion is substantial empirical description of genotype/phenotype interactions that by definition constitute the plastic response to novel and stressful environments. Here, I present empirical observations that bring the interaction of genotype and phenotype into focus. Drosophila melanogaster populations subjected to selection for tolerance to low food or high alcohol conditions each exhibited an enhancement …

Characterization Of Heat Shock Protein A12b As A Novel Angiogenesis Regulator., Rebecca J. Steagall

Electronic Theses and Dissertations

Previously, we cloned Heat shock protein A12B (HspA12B), the newest member of a recently defined subfamily of proteins distantly related to the Hsp70 family that are enriched in atherosclerotic lesions. We have found that HspA12B is predominantly expressed in vascular endothelium, and that it is involved in angiogenesis which we probed by in vitro angiogenesis assays (Matrigel), migration assays and Directed In Vivo Angiogenesis Assay (DIVAA). Hsp70s are molecular chaperones that are inducible by stress and have been found to be anti-apoptotic (Li et al. 2000; Nylandsted et al. 2000; Garrido et al. 2001). Because of its homology to Hsp70, …

Identification Of Chlamydial Iron-Responsive Proteins During Intracellular Growth., Brian D. Dill

Electronic Theses and Dissertations

Chlamydia trachomatis is an obligate intracellular bacterium and the most prevalent cause of bacterial sexually transmitted disease. Genital chlamydial infections, marked by chronic, intense inflammation, can lead to genital tissue scarring and infertility and is a contributing factor to development of pelvic inflammatory disease and ectopic pregnancy. Iron is required as a cofactor for numerous highly conserved pathways, and nearly all studied organisms rely on iron for growth. In response to iron restriction, the chlamydial developmental cycle arrests at the intracellular reticulate body stage, resulting in a phenomenon termed persistence. Persistence likely plays a role in chlamydial pathogenesis through the …

Synthesis Of Novel Agrochemicals As Potential Plant Immunization Agents., Arrey Besong Enyong

Electronic Theses and Dissertations

The world's population is expected to grow from 6 billion to about 10 billion by 2050. The greatest population increase is expected to occur in Africa, Latin America, and Asia. To feed a world with huge increases in population and to sustain the well-being of humans, a large increase in food production must be achieved. The projected increase in food production must be accomplished on the existing cultivated areas because the expansion of new land is limited by environmental concerns, urbanization and increasing water scarcity.

Different compounds have been developed for the "immunization" of plants against several pathogens. These compounds …

The Effect Of Wild Blueberries On Endothelium-Dependent Vasodilation In Spontaneously Hypertensive Rats, Aleksandra S. Kristo

Electronic Theses and Dissertations

The effect of wild blueberries on major endothelium-dependent vasodilation pathways and arterial blood pressure (BP) was examined in the young adult Spontaneously Hypertensive rat (SHR), used as a model of endothelial dysfunction, and the Wistar Kyoto (WK) rat, with functional endothelium, used as the control. Male SHR and WK rats were fed a control (SHR-C and WK-C), or a wild blueberry-enriched (SHR-B and WK-B) diet for nine weeks. By the age of 21 weeks, thoracic aortae were excised and 3mm arterial rings were prepared and immersed in Radnoti tissue baths. Rings were precontractred with phenylephrine (Phe) (10"6M), followed by cumulative …

Effects Of Fish Introductions On The Geographic Distribution And Native Invertebrate Biodiversity Of Naturally Fishless Lakes In Maine, Emily Gaenzle Schilling

Electronic Theses and Dissertations

Widespread fish stocking has led to a worldwide decline in naturally fishless lakes and their associated communities. Little is known about the historical distribution or native communities of these freshwater ecosystems. The objectives of this study were to: 1) develop a quantitative method to remotely detect naturally fishless lakes in Maine, 2) conduct a landscape-scale assessment of unique attributes of fishless lake macroinvertebrate communities, 3) identify macroinvertebrate bioindicators of fish absence, and 4) assess effects of introduced fish on native macroinvertebrates. I identified two physiographic types of naturally fishless lakes in Maine: kettle lakes in the eastern lowlands and foothills …

Structural And Biochemical Investigation Of The Molecular Mechanisms Of Dna Response And Repair In Humans And Escherichia Coli., Steven Michael Shell

Electronic Theses and Dissertations

The genomes of all living cells are under constant attack from both endogenous and exogenous agents that damage DNA. In order to maintain genetic integrity a variety of response pathways have evolved to recognize and eliminate DNA damage. Replication protein A (RPA), the eukaryotic single-stranded DNA (ssDNA) binding protein, is a required factor for all major DNA metabolisms. Although much work has been done to elucidate the nature of the interaction between RPA and ssDNA currently there is no structural information on how the full-length protein binds to ssDNA. This study presents a novel examination of the full nucleoprotein complex …

Gender-Specific Differences In Spatial Behavior Of The Flesh Fly, Sarcophaga Crassipalpis., Caleb Joseph Paquette

Electronic Theses and Dissertations

Territoriality in the flesh fly, Sarcophaga crassipalpis (Diptera: Sarcophagidae) was studied in the laboratory. In rectangular enclosures, male flies exhibited a lower tolerance (occupation of the same physical space) of same-sex conspecifics than did female flies. In circular arenas, male flies showed significantly higher levels of spatial separation among themselves (as determined from nearest neighbor analyses) than did females: males were distributed uniformly whereas females were nearly random. The male spatial behavior occurred during the photophase but not the scotophase of light-dark cycles, suggesting that visual cues are required for maintenance of inter-individual spacing. No significant differences in male spacing …

Antigen Trafficking Within Chlamydia Trachomatis-Infected Polarized Human Endometrial Epithelial Cells., David Kelley Giles

Electronic Theses and Dissertations

Chlamydia trachomatis serovars D-K are the leading cause of bacterially-acquired sexually transmitted infections in the United States. As an obligate intracellular pathogen, C. trachomatis infects columnar epithelial cells of the genital mucosae and can cause deleterious sequelae such as pelvic inflammatory disease, infertility, and ectopic pregnancy. Several chlamydial antigens reach the host cell cytosol prior to the natural release of chlamydiae at the end of the developmental cycle. While some of these extra-inclusion antigens traffic to the host cell surface, others remain intracellular where they are proposed to influence vital host cell functions and antigen trafficking and presentation. The research …

The Effects Of Chronically Elevated N And S Deposition On The Nutrition And Physiology Of Sugar Maple At The Bear Brook Watershed In Maine, Suzanne Bethers

Electronic Theses and Dissertations

The Bear Brook Watershed in Maine is a paired watershed system; one watershed has been acidified bimonthly with granular ammonium sulfate ((NH₄)₂SO₄) since 1989. The adjacent watershed is used as a reference. This acid deposition treatment presents unique opportunities to look at the long term affects of acidification on vegetation. Acidic deposition continues to be a concern for the health of sugar maple (Acer saccharum Marsh.) in northern hardwood forests. Many studies show a connection between base cation depletion induced by acid deposition and sugar maple decline. In this text we …

The Ttc7Fsn/Fsn Mutation Results In Hyperactivation Of Lymphocytes And Overproduction Of Il-4 Leading To The Development Of Systemic Autoimmunity, Beth Lindroth Hill

Electronic Theses and Dissertations

Ttc7^fsn/fsn mice exhibit systemic autoimmunity characterized by hyperactivated B cells, increased interleukin-4, autoantibodies, kidney disease and reduced lifespan. Because the pathology is similar to systemic lupus erythematosus, Ttc7^fsn/fsn mice are a useful model with which to study early events that lead to autoimmune disease. Although the Ttc7^fsn mutation has been identified the gene function is unknown. The phenotype of Ttc7^fsn/fsn mice mimics the Th2 autoimmunity of the IL-4 transgenic (Erb et al 1997). It was previously unknown whether the over-production of IL-4 was an intrinsic defect of Ttc7^fsn/fsn lymphocytes that led to autoimmunity, or, whether …

Lipid Aldehydes Are Substrates And Transcriptional Regulators Of Cytochromes P450., Immaculate Amunom

Electronic Theses and Dissertations

4-hydroxy-2-nonenal (4-HNE) and propene-2-al (acrolein) are highly reactive á,â-unsaturated aldehydes. 4-HNE and acrolein are generated in vivo as products of lipid peroxidation. These aldehydes are implicated in the onset of several diseases including atherosclerosis and neurodegenerative disease. They also react with nucleophilic cellular macromolecules including proteins, DNA and phospholipids. Some of these reactions in vivo lead to inhibition of enzyme activities, depletion of glutathione and oxidative stress. Because of their pathophysiological relevance, attention has focused during the last decade on the ability of mammals to metabolize these lipid aldehydes. The purpose of this study was therefore to determine the role …

Structure-Function Analysis Of The Drosophila Stubble Type Ii Transmembrane Serine Protease, Rachel Morgan

Electronic Theses and Dissertations

Hormonally-triggered regulatory hierarchies play a major role in organismal development. Disruption of a single member of such a hierarchy can lead to irregular development and disease. Therefore, knowledge of the members involved and the mechanisms controlling signaling through such pathways is of great importance in understanding how resulting developmental defects occur. Type II transmembrane serine proteases (TTSPs) make up a family of cell surface-associated proteases that play important roles in the development and homeostasis of a number of mammalian tissues. Aberrant expression of TTSPs is linked to several human disorders, including deafness, heart and respiratory disease and cancer. However, the …

Cis-Regulatory Analysis Of The Pigment Cell Differentiation Gene Polyketide Synthase, David Rogers

Electronic Theses and Dissertations

The analysis of Gene Regulatory Networks (GRNs) is essential to understanding the complete process of embryo development. Elucidating every gene regulatory circuit from maternal regulatory inputs all the way to the activation of differentiation gene batteries is an important step in increasing our understanding of developmental biology. In this work I study the cis-regulatory architecture of a pigment cell differentiation gene, polyketide synthase (SpPks) in the sea urchin Strongylocentrotus purpuratus. SpPks encodes an enzyme that is responsible for the biosynthesis of the sea urchin pigment echinochrome in larval pigment cells. The analysis of the promoter of a differentiation gene will …

Assessing And Modeling Mangrove Forest Dynamics Along The Temperate-Subtropical Ecotone In Eastern Florida, Susan Leitholf

Electronic Theses and Dissertations

Mangrove ecosystems are among the world's most endangered biomes; nearly one-half of the overall coverage is threatened by human activity, invasive species, and global climate change. Mangroves play an important ecosystem role through detrital production and by providing: fisheries and wildlife nursery habitat, shoreline protection, a sink for nutrients, carbon, and sediment. In addition to human activity, the Florida mangroves (Avicennia germinans, Laguncularia racemosa, and Rhizophora mangle) are being threatened by the invasive Brazilian pepper (Schinus terebinthifolius). This study was performed along a 261 km stretch of the east coast of Florida from Sebastian Inlet to the northern extent of …

Hatching Asynchrony Occurs As A Byproduct Of Maintaining Egg Viability, Robert Aldredge

Electronic Theses and Dissertations

For many organisms, embryonic development begins directly after an egg (ovum) has been fertilized by sperm; however, some organisms delay the onset of embryonic development until conditions are favorable for raising young. This delayed onset of development could occur by delaying implantation of fertilized ovum on the uterine wall, as seen in many mammals. Birds delay embryonic development by laying a set of fertilized ova over a period of consecutive days. These fertilized ova are protected from the ambient environment by an exterior shell, and it is in this shell outside of the female s body that embryonic development occurs, …

Recovery And Restoration Of The Seagrass Halodule Wrightii After Boat Propeller Scar Damage In A Pole-Troll Zone In Mosquito Lag, Katherine Grablow

Electronic Theses and Dissertations

This study combined documentation of four boat propeller scar types in Halodule wrightii seagrass beds in Mosquito Lagoon, Florida with manipulative field experiments to document scar recovery times with and without restoration. Scar types ranged from the most severe scar type (Type 1) with trench formation which had no roots or shoots in the trench, to the least severe (Type 4) scars that had no depth, intact roots and shoots shorter than the surrounding canopy. For 110 measured existing scars, the frequency of each scar type was 56% for Type 1, 10% for Type 2, 7% for Type 3, and …

Growth And Survival Of Bacteria In Simulated Martian Conditions, Bonnie Berry

Electronic Theses and Dissertations

Escherichia coli and Serratia liquefaciens, two common microbial spacecraft contaminants known to replicate under low atmospheric pressures of 25 mb, were tested for growth and survival in simulated martian conditions. Stressors of high salinity, low temperature, and low pressure were screened alone and in combination to determine how they might affect microbial activity. Growth and survival of E. coli and S. liquefaciens under low temperatures (30, 20, 10, or 5 °C) with increasing concentrations (0, 5, 10, or 20 %) of three salts believed to be present on the surface of Mars (MgCl2, MgSO4, NaCl) were monitored over 7 d. …

The Distribution, Abundance, And Habitat Use Of The Big Cypress Fox Squirrel, (Sciurus Niger Avicennia)., Danielle Munim

Electronic Theses and Dissertations

Human population growth and development reduce the area and quality of natural communities and lead to a reduction of populations of the species associated with them. Certain species can be useful indicators or "focal species" for determining the quality of ecosystem remnants and the required management practices. Tree squirrels are good models for studies on the effects of fragmentation because they depend on mature forests. The Big Cypress fox squirrel, (Sciurus niger avicennia), a state-listed Threatened subspecies endemic to south Florida, appears sensitive to habitat fragmentation and fire regime. This research aims to assess the conservation status of the Big …

The Endocytic Protein Numb Regulates App Metabolism And Notch Signaling: Implications For Alzheimer's Disease, George Kyriazis

Electronic Theses and Dissertations

Increased production of amyloid beta (A-beta) peptide, via altered proteolytic cleavage of amyloid protein precursor (APP), and abnormalities in neuronal calcium homeostasis play central roles in the pathogenesis of Alzheimer's disease (AD). Notch1, a membrane receptor that controls cell fate decisions during development of the nervous system, has been linked to AD because it is a substrate for the gamma-secretase protein complex in which mutations cause early-onset inherited AD. Numb is an evolutionarily conserved endocytic adapter involved in the internalization of transmembrane receptors. Mammals produce four Numb isoforms that differ in two functional domains, a phosphotyrosine-binding domain (PTB) and a …

Prostasin Is Expressed In Benign Prostatic Hyperplasia And Regulates Cell Proliferation And Invasion Via Inos, Icam-1, And Cycli, Meghan Hatfield

Electronic Theses and Dissertations

Prostasin is expressed in normal prostate epithelial cells but down-regulated in prostate cancers, while prostasin re-expression in invasive prostate cancer cells reduced invasion. We examined prostasin expression and function in benign prostatic hyperplasia (BPH). We evaluated prostasin expression in 12 BPH specimens by immunohistochemistry, and evaluated the impact of prostasin silencing by siRNA on the expression of the inducible nitric oxide synthase (iNOS), intercellular adhesion molecule-1 (ICAM-1), and cyclin D1, as well as on cell proliferation and invasion, using the BPH-1 human prostate epithelial cell line model. Prostasin expression was localized in the glands of BPH tissues by immunohistochemistry, in …