Microbiology Commons^™

Amino Acid Racemase Enzyme Assays, Atanas D. Radkov, Luke A. Moe

Plant and Soil Sciences Faculty Publications

Amino acid racemases are enzymes that invert the α-carbon stereochemistry of amino acids (AAs), interconverting amino acids between their L- and D-enantiomers in a reversible reaction. In bacteria, they are known to have catabolic physiological functions but are also involved in the synthesis of many D-AAs, including D-glutamate and D-alanine, which are necessary components of the peptidoglycan layer of the bacterial cell wall. As such, amino acid racemases represent significant targets for the development of bactericidal compounds. Amino acid racemases are also regarded by the biotechnological industry as important catalysts for the production of economically relevant D-AAs. Here, we provide …

Genetic Basis For The Virulence Of Enterohemorrhagic Escherichia Coli Strain Tw14359, Jason Kyle Morgan

USF Tampa Graduate Theses and Dissertations

Enterohemorrhagic Escherichia coli (EHEC) is a virulent pathotype of E. coli that is associated with major outbreaks of hemorrhagic colitis and the life-threatening kidney disease hemolytic uremic syndrome. For successful host colonization and attachment to the intestinal mucosa, EHEC requires the locus of enterocyte effacement (LEE) pathogenicity island, which encodes a type III secretion system (TTSS) responsible for secreting and translocating effector proteins into host colonocytes. Regulation of the LEE is primarily directed through the first operon, LEE1, encoding the locus encoded regulator (Ler), and occurs through the direct and indirect action of several regulators. The 2006 U.S. spinach outbreak …

Investigating Antibiotic Resistance Levels Of Salmonella Internalized In Lettuce Leaves, Jason B. Thomas

McNair Scholars Research Journal

Contamination of food crops by the human pathogen Salmonella is a food safety threat worldwide. Though using treated wastewater for irrigation is a sustainable practice, it may introduce trace levels of Salmonella that may contaminate food crops. Salmonella could develop resistance to antibiotics present in wastewater. The overall goal of the project is to increase the understanding of the public health risk associated with the use of treated wastewater to irrigate food crops. The objective of this particular study is to determine the antibiotic resistance level of Salmonella internalized in lettuce leaves. In this experiment, thirty-six plants of the lettuce …

Characterization Of A Putative Cephalotoxin From The Hemocytes Of Euprymna Scolopes, Jessie E. Scott

University Scholar Projects

Many organisms have beneficial microbial symbionts, and complex interactions between the immune system and the bacteria must occur to allow these symbioses to persist. The host immune system must recognize and preferentially tolerate the beneficial microorganisms, while simultaneously eliminating harmful pathogens. The Hawaiian bobtail squid, Euprymna scolopes, is a model organism for host-microbe interactions because of the unique light organ symbiosis. Hemocytes, the squid’s primary immune cell, infiltrate and patrol the light organ and continuously interact with the symbiont Vibrio fischeri. Using this model, several innate immunity genes have been shown to be differentially expressed in the hemocytes …

Polymorphic Membrane Protein Expression In Chlamydia/Hsv Co-Infected Cells, Julia S. Colgrove

Undergraduate Honors Theses

The Chlamydiaceae are a bacterial family that contains a single genus: Chlamydia. The genus Chlamydia consists of 9 species that are obligate, intracellular pathogens. Untreated C. trachomatis infections can lead to serious health ramifications, such as ectopic pregnancy, tubal factor infertility, pelvic inflammatory disease, and long-term pelvic pain. In this study, it was found that a primary antibody dilution of 1:400 using methanol fixed HeLA cells, as derived from Carrasco, et al. protocol, was only optimal for PMP-C staining. Pmp-A, Pmp-B, and Pmp-F were found to stain brighter with formaldehyde fixed, infected HeLa cells and using different primary antibody dilutions. …

An Examination Of Keratinophilic Fungal On Eastern Bluebird Eggshells, Edward Anthony Hillman Iii

Undergraduate Honors Theses

This study was designed to evaluate the mycobiota of Eastern Bluebird eggshells and assess the abundance of keratinophilic fungi. Samples of fungi taken from Eastern Bluebird eggshells were subcultured for identification using macroscopic and microscopic characteristics. The occurrence of a significant number of keratinophilic fungi on Eastern Bluebird eggshells poses a potential threat to developing chicks.

Plant-Microbial Interactions Change Along A Prairie Restoration Chronosequence, Anna Herzberger

Undergraduate Honors Theses

Soil microbial communities are critical in determining the performance and density of species in plant communities. However, their role in regulating the success of restorations is much less clear. This study assessed the ability of soil microbial communities to regulate the growth and performance of two potentially dominant grasses and two common forbs in prairie restorations. Specifically, I examined the effects of soil microbial communities along a restoration chronosequence from agricultural fields to remnant prairies using experimentally inoculated soils. The two grass species, Andropogon gerardii and Sorghastrum nutans, produced larger biomass with the agricultural inoculates and experienced a decline …

Cell Kinase Inhibitor Panel Reveals Multiple Targets To Prevent Replication Of Varicella-Zoster Virus, Bryan Egan Bunnell

Renée Crown University Honors Thesis Projects - All

The alphaherpesvirus that causes chicken pox and shingles, varicella-zoster virus (VZV), infects skin fibroblasts and keratinocytes. These cells are typically quiescent and it is known that VZV manipulates their intracellular environment to activate MAPK signaling cascades, cell cycle regulators, and many transcription factors for its replication. We hypothesized that inhibition of cell kinases would prevent VZV replication and also elucidate which pathways are most important. We evaluated 80 kinase inhibitors for cytotoxicity and anti-proliferative effects on human foreskin fibroblasts, and then determined their antiviral efficacy against VZV-ORF9-Luc strain. Ten well-tolerated, potent kinase inhibitors whose targets are critical mediators of VZV …

Population Dynamics Of Triticum Mosaic Virus In Various Host Species, Melissa S. Bartels

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

It has been established that RNA viruses should be genetically diverse, due to the high error rate of their RNA-dependent RNA polymerases and the lack of proof-reading capabilities. Plant RNA viruses are not as genetically diverse as expected. Evolutionary factors, such as purifying selection and bottlenecks that favor genetic stability, might be affecting plant viral populations. Otherwise RNA virus populations, with their potential for extreme diversity, might acquire a lethal number of mutations leading to the collapse of the population.

Triticum mosaic virus (TriMV) populations maintained in a controlled greenhouse environment displayed genetic stability. The mutation frequency per nucleotide of …

Fruiting Bodies Of The Social Amoeba Dictyostelium Discoideum Increase Spore Transport By Drosophila, Jeff Smith, David C. Queller, Joan E. Strassmann

Biology Faculty Research

Background: Many microbial phenotypes are the product of cooperative interactions among cells, but their putative fitness benefits are often not well understood. In the cellular slime mold Dictyostelium discoideum , unicellular amoebae aggregate when starved and form multicellular fruiting bodies in which stress-resistant spores are held aloft by dead stalk cells. Fruiting bodies are thought to be adaptations for dispersing spores to new feeding sites, but this has not been directly tested. Here we experimentally test whether fruiting bodies increase the rate at which spores are acquired by passing invertebrates.
Results: Drosophila melanogaster accumulate spores on their surfaces more quickly …

Study Of The Function Of The Mold Specific Gene Ms95 In Dna Repair In The Pathogenic, Dimorphic Fungus Histoplasma Capsulatum, Erin M. Smith

Honors Theses

Histoplasma capsulatum (Hc) is a dimorphic fungus that is the etiologic agent of the respiratory infection Histoplasmosis that is mediated by a shift from the mold phase to the pathogenic yeast phase. Genes have been identified that are specific to the mold or yeast phase in order to study the molecular biology of this shift. MS95 was identified in a subtractive cDNA library that was enriched for mold-specific genes, and has been found to be homologous to the DNA damage-responsive gene DDR48, which functions in DNA repair in Saccharomyces cerevisiae. In order to elucidate the function of MS95, a …

Effect Of Preanalytical Processing Of Thinprep Specimens On Detection Of High-Risk Human Papillomavirus By The Aptima Hpv Assay, Erik Munson, Elizabeth R. Schroeder, Kevin C. Ross, Connie Yauck, Theresa Bieganski, Robert D. Amrhein, Maureen Napierala, April L. Harkins

Clinical Lab Sciences Faculty Research and Publications

Two important preanalytical protocols performed on liquid-based cytological specimens, namely, automated cytology processing and glacial acetic acid (GAA) treatment, may occur prior to the arrival of specimens in a molecular diagnostics laboratory. Ninety-two ThinPrep vials previously positive for high-risk human papillomavirus (HPV) via the Cervista HPV HR test were preselected and alternated with 92 previously negative ThinPrep vials. The specimen set was processed in a consecutive fashion by an automated cytology processor without fastidious decontamination precautions. Carryover potential was subsequently assessed by performance of the Aptima HPV assay on aliquots from reprocessed ThinPrep vials. All previously negative ThinPrep vials yielded …

Rates Of Evolution And Point Mutations Of Bacterial Plant Pathogens Compared To Bacterial Vertebrate Pathogens, Alejandro Cantu

Theses and Dissertations - UTB/UTPA

The relationship between a pathogen and its host is a constant interaction; as the host evolves defense mechanisms to protect itself from the pathogen, the pathogen will evolve in order to evade them. During this evolutionary process, the genomes of bacterial pathogens can change due to different selection pressures exerted by the immune system of their respective hosts. This study aimed to determine how differences in selection pressures affect the evolution of plant and vertebrate pathogens. The focus of this study was to analyze population level changes in conserved genes, as well as species level changes in the Type III …

Sa-4-1bbl As A Platform To Develop Adjuvant Systems For Prophylactic And Therapeutic Vaccines., Gunes Dinc 1984-

Electronic Theses and Dissertations

Vaccines against infectious diseases are one of the most critical accomplishments in modern medicine. Despite significant progress in vaccinology, there is still a dire need for developing vaccines against various acute and chronic infections and cancer. In general, vaccines are categorized as prophylactic, given to healthy individuals to prevent disease, and therapeutic, administered to people who already have disease. As such, the nature, quality, and quantity of immune responses required for the efficacy of these two types vaccines are different. Prophylactic vaccines against infectious diseases primarily rely on the generation of neutralizing high titers of antibody for their efficacy. These …

Functional Analysis Of Cytosolic Hsp70 Nucleotide Exchange Factor Networks In Yeast, Jennifer Lynn Abrams

Dissertations and Theses (Open Access)

The Hsp70 class of molecular chaperones play critical roles in protein homeostasis via an ATP-dependent folding cycle. Cytosolic Hsp70s in the budding yeast Saccharomyces cerevisiae, Ssa and Ssb, interact with up to three distinct nucleotide exchange factors (NEFs) homologous to human counterparts; Sse1/Sse2/HSP110, Fes1/HspBP1, and Snl1/Bag1. In an effort to understand the differential functional contributions of the cytosolic NEFs to protein homeostasis (“proteostasis”), I carried out comparative genetic, biochemical and cell biological analyses. For these studies, I developed protocols to monitor protein disaggregation and reactivation in a near real-time coupled assay that revealed the importance of aggregate dynamics in the …

Characterization Of Tonb In Rhizobium Leguminosarum Atcc 14479, Brian D. Hill

Electronic Theses and Dissertations

Rhizobium leguminosarum is a gram-negative soil bacterium that requires iron for survival. However, iron becomes insoluble in the presence of oxygen at physiological pH. In response, Rhizobia species have used siderophore mediated iron transport systems to meet their iron requirements. R. leguminosarum ATCC 14479 produces the trihydroxymate siderophore vicibactin and we hypothesize that the import of the ferric iron-vicibactin complex is energized by the TonB-ExbB-ExbD system. Here, we have identified a putative tonB gene. A tonB mutant was created and compared with wild type in its ability to transport ⁵⁵Fe-vicibactin. Also, the putative TonB of R. leguminosarum ATCC …

The Role Of Human Norovirus Surrogates, Feline Calicivirus And Murine Norovirus, On Non-Porous And Soft Porous Surfaces, Thomas Yeargin

All Theses

Human Noroviruses (HuNoV) are the leading cause of acute gastroenteritis worldwide as well as the leading cause of foodborne disease in the U.S. HuNoV can persist in the environment even after proper disinfection, making preventing HuNoV infections and controlling subsequent outbreaks extremely challenging. Epidemiological evidence suggests that soft surfaces may be a relevant source of HuNoV due to the inability to effectively decontaminate. The objectives of this study were to: 1) review the current published literature on prevalence, transmission, and disinfection pertaining to HuNoV and surrogates with an emphasis on soft surfaces as fomites, 2) optimize a recovery method capable …

Determining The Presence Of Carbapenem Antibiotic Resistance In Clinical Isolates, Fidelis Uzoma Enyinnaya

UNLV Theses, Dissertations, Professional Papers, and Capstones

Carbapenems are β-lactam antibiotics reserved for the treatment of severe microbial infections, especially those targeting the Enterobacteriaceae. Introduced in the 1980s, carbapenems have been used successfully in hospitals, and in the 1990s resistance was discovered. Carbapenem resistance is conferred through the production of carbapenemases. In the U.S., the most common carbapenemase is Klebsiella pneumoniae carbapenemase (KPC). In 2012, the National Healthcare Safety Network reported a carbapenem resistance rate of 13.0% among Klebsiella pneumoniae infections, and indicated that the mortality rate associated with carbapenem resistant Enterobacteriaceae (CRE) infections ranged from 48.0-71.9%. According to the Food and Drug Administration (FDA), carbapenem resistance …

Isolation And Characterization Of Paenibacillus Larvae Bacteriophages For Use As A Treatment Of American Foulbrood Disease In Honeybees, Diane Gerda Yost

UNLV Theses, Dissertations, Professional Papers, and Capstones

American foulbrood disease is a destructive honeybee illness cause by the bacterial pathogen, Paenibacillus larvae. Current methods of treatment are either destructive or do not completely eradicate the infection, and as such, undertaking further research to determine the effectiveness of alternate treatment methods is of consequence.

The therapeutic use of bacteriophage that are capable of lysing host bacterial cells, or phage therapy, is one such potential treatment. Phage are viruses that infect bacteria, and are generally very host-specific. As such, targeting a pathogen would require obtaining phage specific for P. larvae. Therefore, obtaining P. larvae phage requires screening environmental samples …

Regulation Of Macrophage Inflammatory Signaling Pathways By Amp-Activated Protein Kinase., Yanfang Zhu

Electronic Theses and Dissertations

AMP-activated protein kinase, AMPK, is a conserved serine/threonine kinase with a critical function in the regulation of metabolic pathways in eukaryotic cells. Recently, AMPK has been shown to play an additional role as a regulator of inflammatory activity in leukocytes. Treatment of macrophages with chemical AMPK activators, or forced expression of a constitutively active form of AMPK, results in polarization to an antiinflammatory phenotype. Additionally, we reported previously that stimulation of macrophages with antiinflammatory cytokines such as IL-10, IL-4 and TGF-ß results in rapid activation of AMPK, suggesting that AMPK contributes to the suppressive function of these cytokines. In the …