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Advances in yeast and mold monodrug and combination drug antifungal susceptibility testing: Author: Wetter, Tracy Jane; Date: 2004-05-15; Program: Microbiology; Abstract: Advances were made in both yeast and mold rapid susceptibility assay (RSA) testing. The yeast RSA was modified to facilitate amphotericin B (AMB), itraconazole (ITC), and voriconazole (VRC) testing of Aspergillus fumigatus, A. terreus, and A. flavus clinical isolates. 16 h mold RSA AMB, ITC, and VRC RSA minimum inhibitory concentration (MIC) values were equal to or within a single, two-fold dilution of MICs obtained in 48 h with the National Committee for Clinical Laboratory Standards (NCCLS) M38-A assay and in 24 or 48 h with the mold Etest. Preliminary testing with A. sydowii, Scedosporium a...; Download File | View full details

Analysis of the small GTP binding protein Rac2: Author: Snodgrass, Meagan Alyssa; Date: 2005-08-15; Program: Microbiology; Abstract: Human neutrophils serve as the first line of immune defense against invading pathogens. In many cells, including neutrophils, Rac proteins are key regulators of many diverse cellular functions through their affects on cytoskeletal organization and in neutrophils, the NADPH oxidase complex, a critical mechanism for host defense. The primary purpose of this research is to examine the possibility that Rac2 interacts directly with the actin cytoskeleton. A different small GTP binding protein, Rap2 has been shown to interact with actin through direct binding. To test our hypothesis, GST-Rac2 and GS...; Download File | View full details

Molecular Analysis of Diversity, Gene Expression and Activity of Mineral-Associated Bacteria: Author: Reardon, Catherine Leona; Date: 2005-12-15; Program: Microbiology; Abstract: This dissertation investigated the diversity and hydrogenase activity and gene expression of mineral-associated microorganisms. Surface-associated microbes have been shown to dominate diversity and activity in the environment, however molecular analysis of sediment-associated communities is hindered by both inaccessibility to the subsurface and co-extraction of inhibitory compounds. In order to analyze microbial communities in which the environmental conditions previously had precluded the use of traditional sediment extraction techniques, biofilm coupons (metal, mesh cylinders containing surr...; Download File | View full details

Pseudomonas aeruginosa Biofilm Structure, Behavior and Hydrodynamics: Author: Purevdorj-Gage, Boloroo; Date: 2004-12-15; Program: Microbiology; Abstract: Biofilm formation by bacterial pathogens is an important factor in the progression and treatment of many infectious diseases. Biofilm structural development is a dynamic process dependent on many cellular and environmental parameters including Quorum Sensing (QS) and hydrodynamics. Since QS is dependent on a threshold autoinducer concentration, it was hypothesized that the flow dynamics in the bulk fluid surrounding the biofilm would play an important role in expression of QS and the genes that are under its control. In order to investigate the relative contribution of hydrodynamics and QS on ...; Download File | View full details

The Role of the Recruited Neutrophil in the Innate Response to Aspergillus fumigatus: Author: Bonnett, Colin Russell; Date: 2005-05-15; Program: Microbiology; Abstract: Strong clinical and experimental evidence links qualitative and quantitative neutrophil deficiencies to fatal infections caused by A. fumigatus. Yet the role of the neutrophil in mediating the protection observed in normal hosts remains largely unknown. Recent studies indicate neutrophils from CXCR2-/- mice are unable to migrate toward chemokine gradients of KC and MIP-2, rendering these animals susceptible to fatal aspergillosis. Mice with a mutation in the gene encoding for the gp91phox component of the NADPH oxidase lack the ability to generate the reactive oxygen metabolites used by phagoc...; Download File | View full details

Analysis of Pseudomonas aeruginosa virulence in modeled microgravity conditions: Author: Guadarrama-Beltran, Seratna; Date: 2006-08-15; Program: Microbiology; Abstract: Spaceflight conditions may enhance bacterial growth, alter antimicrobial susceptibility and possibly affect virulence. Since spaceflight causes astronauts to experience secondary immunosuppression, increased virulence would increase the risk of infection. Limited opportunities for spaceflight experiments necessitate ground-based simulations. Clinostats and rotating wall vessel bioreactors, e.g. High Aspect Ratio Vessels (HARVs) are used to simulate microgravity effects at 1xg. Clinostat and HARV rotation on the horizontal axis results in the g-vector being time averaged to near zero. In contro...; Download File | View full details

Virus dynamics, archaeal populations, and water chemistry of Three Acidic Hot Springs in Yellowstone National Park: Author: Snyder, Jamie Christine; Date: 2005-05-15; Program: Microbiology; Abstract: Few viruses from Archaea have been described and only a limited number have been characterized in molecular detail. Most hyperthermophilic viruses isolated from the archaeal sub-domain Crenarchaeota belong to the Sulfolobales family. We have focused on the isolation and analysis of viruses replicating in Sulfolobus. Sulfolobus is an acidophilic hyperthermophile that lives optimally at 80°C and pH 3. The SSVs (Sulfolobus spindle-shaped viruses) are the viruses most commonly isolated from thermal acidic areas around the world. SSVs are dsDNA spindle-shaped viruses with genomes of appr...; Download File | View full details

Modulation of the Plasma Membrane Domain Structure of Human Neutrophils: Author: Stie, Jamal Talal; Date: 2006-08-15; Program: Microbiology; Abstract: Eukaryotic cell plasma membranes form an interface between cells and their environment and function to detect and interpret environmental cues. The work described in this dissertation examines the changes that occur in membrane structure during plasma membrane function in human neutrophils and a fungal opportunist. The body of this work examines how circulating neutrophils can remain functionally inactive in the presence of perturbing influences inherent in the blood circulation, and yet rapidly activate upon exposure to proinflammatory agents. It is hypothesized that the regulated modulation ...; Download File | View full details

The Search for Archaeal Viruses in High Temperature Acidic Environments and Characterization of Sulfolobus Turreted Icosahedral Virus (STIV): Author: Rice, George Ernest; Date: 2006-12-15; Program: Microbiology; Abstract: Viruses of extreme thermophiles are of great interest because they can serve as model systems for understanding biochemical molecular nuances required for life at high temperatures. This two part body of work first reports the discovery and isolation of viruses and virus-like particles from extreme thermal acidic environments (70-92°C, pH 1.0-4.5) in Yellowstone National Park (YNP), and secondly details the characterization of one of these viruses that possesses a capsid structural motif that is found in at least two other families of viruses inhabiting the other two domains of life...; Download File | View full details

Protein Cage Architectures for Targeted Therapeutic and Imaging Agent Delivery: Author: Flenniken, Michelle Lynne; Date: 2006-05-15; Program: Microbiology; Abstract: Protein cage architectures such as viral capsids, heat shock proteins, and ferritins are naturally occurring spherical structures that are potentially useful nanoscale platforms for biomedical applications. This dissertation work demonstrates the utility of protein cages including their use as therapeutic and imaging agent delivery systems. Protein cage architectures have clearly demarcated exterior, interior, and interface surfaces and their structures are known to atomic level resolution. This information is essential for the engineering of functionalized nanoparticles via both chemical and ...; Download File | View full details

Spectrophotometric, Mass Spectrometeric and Structural Studies of the Prototypical G Protein Coupled Receptor Rhodopsin: Author: Angel, Thomas Emil; Date: 2007-05-15; Program: Microbiology; Abstract: Rhodopsin is the integral membrane protein responsible for black and white vision in low light conditions and is found at high concentration in the mammalian retina. Rhodopsin is a prototypical member of the G protein coupled receptor super family that control much of physiology. Improved understanding of rhodopsin signal transduction and amplification via coupling to the heterotrimeric G protein transducin may reveal conserved activation mechanisms that are relevant to other members of the GPCR super family. Described here are several studies that examine the molecular determinants responsibl...; Download File | View full details

Sulfolobus as a model organism for the study of diverse biological interests: forays into thermal virology and oxidative stress: Author: Wiedenheft, Blake Alan; Date: 2006-12-15; Program: Microbiology; Abstract: My research interests have focused on two distinct aspects of Sulfolobus biology: virology and oxidative stress. My major contribution to the emerging field of thermal virology has been the isolation, characterization and comparative genomic analysis of a spindle-shaped virus partical (SSV RH) infecting the thermoacidophilic archaeal host Sulfolobus solfataricus (18). Insights from this comparative genomic analysis have served as a platform for targeted structural studies, as well as providing molecular tools used to follow the viral life cycle in culture and for assessing the ecological signi...; Download File | View full details

Growth of Mycobacterium avium in dual species biofilms with Pseudomonas aeruginosa: Author: Karmacharya, Amresh Prasad; Date: 2007-05-15; Program: Microbiology; Abstract: Interest in the growth of M. avium in biofilms has increased in the last few years. Research has shown that M. avium cells in biofilms are more resistant to disinfectants than their planktonic counterparts. Although M. avium has been detected in biofilms in in situ and laboratory models, information available on M. avium is limited compared to biofilm model species such as Pseudomonas aeruginosa, Escherichia coli, Staphylococcus and Streptococcus. The main objective of the present research was to study the growth of M. avium in biofilms in the presence of P. aeruginosa. Biofilms were grown in...; Download File | View full details

Biology of acid-sulfate-chloride springs in Yellowstone National Park, Wyoming, United States of America: Author: Boyd, Eric Stephen; Date: 2007-08-15; Program: Microbiology; Abstract: This dissertation investigated the role of biology in several biogeochemical cycles in acid sulfate chloride (ASC) geothermal springs in Yellowstone National Park (YNP). Elemental sulfur (S°) is associated with many geothermal springs, yet little is known about the organisms involved in its cycling. The aqueous and solid phase geochemistry near the source of Dragon Spring, an ASC spring in the Norris Geyser Basin (NGB) of YNP, was used to guide the enrichment and isolation of two novel S°-reducing Crenarchaeota affiliated with the order Desulfurococcales. Both isolates ar...; Download File | View full details

Studies of peptide mimicry of the group B Streptococcus type III capsular polysaccharide antigen: Author: Pomwised, Rattanaruji; Date: 2007-12-15; Program: Microbiology; Abstract: Capsular polysaccharide (CPS) of Streptococcus group B (GBS) is a poor immunogen and functions as T cell independent antigen, eliciting low IgG antibody with deficient immunologic memory. We previously identified a peptide, S9, which mimics CPS of type III GBS. Here we have taken steps to develop the mimetic peptide as a vaccine against GBS group III. We enhanced the immunogenicity of the peptide by presenting it on the coat protein of Cowpea Chlorotic Mottle Virus (CCMV). And we searched for better mimetic peptides by constructing a secondary phage display library. To accomplish the first goa...; Download File | View full details

Environmental and genetic factors leading to Mycobacterium Avium biofilm formation: Author: Geier, Henriette; Date: 2008-05-15; Program: Microbiology; Abstract: This dissertation investigated the role of environmental and genetic factors that lead to biofilm formation by the environmental and waterborne pathogen Mycobacterium avium. The bacterium causes respiratory and also cutaneous disease predominantly in immunocompromised patients, but infection also occurs in otherwise healthy individuals. M. avium has been frequently isolated from drinking water and it has been shown that the bacterium forms biofilms in drinking water systems. Biofilms show enhanced resistance to antibiotics and disinfectants and therefore are difficult to combat. Biofilm format...; Download File | View full details

The two-component signal transduction systems of Pseudomonas aeruginosa: Author: Richard, Jessica; Date: 2008-08-15; Program: Microbiology; Abstract: Two-component signal transduction systems are important components for bacteria, because they allow the bacteria to sense environmental conditions and rapidly adapt to changes in the environment. Two-component systems generally contain a sensor histidine kinase, which detects an environmental signal and responds by autophosphorylation at a histidine residue using ATP as the phosphate donor. The phosphate group is then transferred to an aspartate residue in the receiver domain of the second component, the response regulator, which in its activated form responds by stimulating or repressing gene...; Download File | View full details

Keys to unlocking the biofilm phenotype of a virulent environmental isolate of Salmonella: Author: Clark, Stewart James; Date: 2008-12-15; Program: Microbiology; Abstract: The aim of this research was to elucidate the phenotypic adaptation of an environmental isolate of Salmonella enterica grown in a single species biofilm using transcriptomic analysis. This environmental isolate was obtained from an outbreak in Gideon, MO, and was classified as Salmonella enterica serotype Missouri. Gene expression profiles obtained from this environmental isolate were compared with profiles of the ATCC type strain Salmonella enterica serotype Typhimurium LT2 grown under the same conditions. It was shown that there were distinct transcriptional differences in both of the strain...; Download File | View full details

Protein-Protein interactions involved in the biogenesis of eukaryotic small ribosomal subunits: Author: Castle, Cathy Lynn; Date: 2008-12-15; Program: Microbiology; Abstract: Ribosome biogenesis is a complicated process involving numerous proteins and modification factors. The process has been well-documented in prokaryotic cells where it is much less complex than the process involved in eukaryotic cells. In eukaryotes, much of what is known about ribosome biogenesis has been learned from studies in the yeast Saccharomyces cerevisiae. Far less has been learned about higher eukaryotes such as humans. However, among organisms in all three domains of life, ribosome structure and function is well conserved. The biogenesis of ribosomal subunits is dynamic, complicated, ...; Download File | View full details

DNA binding proteins of archaeal viruses: Author: Geary, Joella Suzanne; Date: 2008-12-15; Program: Microbiology; Abstract: Archaea are single-celled organisms comprising the third domain of life. The Achaeal species Sulfolobus are infected by the Fuselloviridae virus family: SSV1, SSV2, SSV-RH, and SSV-K. The genomes of these viruses have been annotated and contain putative DNA-binding proteins. The purpose of this work is to identify DNA sequences bound by the SSV1 putative DNA-binding protein C43. C43 protein was cloned, expressed, purified, and assayed at various temperatures for interaction with three SSV1 DNA sequences. C43 binds the T5-promoter, T6-promoter, and C43-promoter sequentially and consistently. Ad...; Download File | View full details

Vascular shutdown as an effect of using photodynamic therpay to treat cancer: Author: Pascucci, Elizabeth Mary; Date: 2008-12-15; Program: Microbiology; Abstract: Photodynamic therapy (PDT) is a treatment that uses the combination of a photosensitizing drug and light to selectively kill cancer cells. PDT has many potential advantages such as minimal side effects, excellent cosmetic results, and no cellular resistance burdening traditional cancer treatments such as chemotherapy and radiation. Currently used in the clinic, a limitation is depth of light penetration; therefore, PDT can only be used to treat superficial disease. Our novel PDT agent utilizes two-photon laser technology, which increases the depth of light penetration, greatly increasing the p...; Download File | View full details

Quantative assessment of localized growth rates and gene expression patterns in Pseudomonas aeruginosa biofilms: Author: Perez-Osorio, Ailyn Cecilia; Date: 2009-05-15; Program: Microbiology; Abstract: This dissertation work provides evidence of heterogeneity in the distribution of gene expression and growth rates among surface associated cells of Pseudomonas aeruginosa. Currently, methodologies used for characterizing biofilm heterogeneity are constrained by the need of in vitro biofilm growth and by the need to genetically manipulate bacteria. This dissertation describes findings obtained by using LCMM, qRT-PCR, qPCR and microarrays. Through combining LCMM with qRT-PCR a housekeeping gene and two quorum sensing induced genes were found to be differentially expressed at the periphery of P. ...; Download File | View full details

Reductive transformation of 2,4,6-Trinitrotoluene by Yarrowia lipolytica AN-L15 under conditions of different initial pH of the culture medium or in the presence of ferrihydrite: Author: Pannier, Andy Joseph; Date: 2009-05-15; Program: Microbiology; Abstract: Batch and column studies were conducted to examine the difference in the transformation pathways of 2,4,6-trinitrotoluene (TNT) reduction by a hemiascomycetous yeast (Yarrowia lipolytica AN-L15) under conditions of different initial pH of the culture medium or in the presence or absence of ferrihydrite. Using high performance liquid chromatography (HPLC), it was observed that Y. lipolytica AN-L15 was able to transform TNT at three different initial proton concentrations of the culture medium: pH 7.0, pH 6.5, and pH 4.5. In the presence of TNT, Y. lipolytica AN-L15 showed preferential growth (O...; Download File | View full details

Characterization and isolation of Archael thermophilic hosts and viruses from Yellowstone National Park: Author: Spuhler, Joshua Lupine; Date: 2009-08-15; Program: Microbiology; Abstract: My research is focused on the identification and characterization of new archaeal viruses that inhabit the thermal features of Yellowstone National Park (YNP). I have undertaken the systematic survey of more than 90 different thermal features found in Yellowstone through a variety of means including culturing of hosts, MDA amplification, qPCR for known archaeal viruses, 16S rRNA gene analysis of potential resident archaeal hosts, tangential flow and end point filtration approaches to sample new viruses, and general water geochemical analysis. From this work a new host has been isolated from YN...; Download File | View full details

Analysis of methane producing communities within underground coal beds: Author: Barnhart, Elliott Paul; Date: 2011-12-15; Program: Microbiology; Abstract: The Powder River Basin in southeastern Montana and northeast Wyoming is the largest source of coal mined in the United States but most of the coal contained in the basin is buried too deeply to be economically accessible. These remote coal beds are dynamic zones where biogeochemical processes work to sustain a microbial ecosystem. Previous work has shown that a direct byproduct of these microbial processes is biogenic methane that can be harvested and utilized as an energy source. Methane is the principle component of natural gas and this can be used as an energy source for electricity generat...; Download File | View full details

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