Microbiology Commons^™

To Mid-Cell And Beyond: Characterizing The Roles Of Gpsb And Ypsa In Cell Division Regulation In Gram-Positive Bacteria, Robert S. Brzozowski

USF Tampa Graduate Theses and Dissertations

The bacterial cell division protein FtsZ is a tubulin homolog that forms a ring-like structure at the site of cell division in most bacterial species. There it acts as a scaffold, aiding in the recruitment of other divisome proteins to the site of cell division. Furthermore, studies focusing on the role of FtsZ treadmilling and septal peptidoglycan synthesis implicates that FtsZ plays a direct role in the ultimate closure of the division septum. Thus, many studies in the field of bacterial cell division have focused on FtsZ in terms of its spatial and temporal regulation as well as its ability …

Targeting The Eskape Pathogens By Botanical And Microbial Approaches, Emily Dilandro

USF Tampa Graduate Theses and Dissertations

There is a vital need to find new clinical treatment options to combat ESKAPE pathogen infections. Nature has thus far been the most fruitful at providing antimicrobial compounds, which have been derived from a plethora of sources. Ranging from plants to microbial communities, these organisms create chemical compounds that are used as defense mechanisms against invasive or encroaching organisms and confer the producers with competitive advantages. In this study, cinnamaldehyde was investigated as a botanical approach to finding active antimicrobial compounds that inhibit the ESKAPE pathogens. Here, we show that all the ESKAPE pathogens are inhibited by cinnamaldehyde concentrations between …

The Ecology And Conservation Of An Urban Karst Subterranean Estuary, Robert J. Scharping

USF Tampa Graduate Theses and Dissertations

Sulphur Springs is an artesian spring and part of the limestone karst topography of metropolitan Tampa, Florida, USA. Underlying this spring is an extensive cave system that hosts saltwater vents and conspicuous microbial biofilm communities. For decades, water from Sulphur Springs has been extracted and used to supplement public water supply and dry season flows in the Hillsborough River Estuary. This dissertation describes research conducted at Sulphur Springs to determine the impacts of urban land use on the underlying cave and downstream estuary ecosystems, and presents the use of this system as a model to fill certain ecological knowledge gaps. …

The Role Of Secreted Proteases In Regulating Disease Progression In Staphylococcus Aureus, Brittney D. Gimza

USF Tampa Graduate Theses and Dissertations

Staphylococcus aureus is a highly successful pathogen capable of producing a wealth of virulence factors in the human host. Of note, ten extracellular proteases are produced alongside these virulence factors and play a multifaceted role during infection. They not only cleave host proteins to promote bacterial invasion, immune evasion and survival, but also control disease progression by modulating the stability of self-derived pathogenic determinants. The importance of the secreted proteases modulating virulence factor stability is evidenced by our groups previous finding that a protease-null strain has a substantially increased infectious capacity in a murine model of sepsis; resulting from the …

The Adaptations Of The Sulfur-Oxidizing, Gammaproteobacterium "Candidatus Endoriftia Persephone", Endosymbiont Of The Giant Tubeworm Riftia Pachyptila, To Hydrothermal Vent Habitat Heterogeneity, Juliana M. Leonard

USF Tampa Graduate Theses and Dissertations

The siboglinid tubeworm Riftia pachyptila is a dominant member of the deep-sea megafauna where seawater and hydrothermal vent (HTV) effluent interface and mix. It is one of the fastest growing invertebrates on land or in the sea. It does not have a digestive tract (e.g. mouth, gut, or anus), and is completely dependent on its sulfur-oxidizing endosymbiont, the Gammaproteobacterium “Candidatus Endoriftia persephone” for its nutritional requirements. This association was the first and is the most well studied among chemolithoautotrophic symbioses. “Ca. E. persephone” is a chemolithoautotrophic bacterium that oxidizes sulfide as an electron donor for energy, reduces oxygen as a …

Targeting Bacterial Resistance And Cancer Metastasis: A Structure Based Approach, Kyle Galen Kroeck

USF Tampa Graduate Theses and Dissertations

Current research in pharmaceutical development commonly utilizes a profusion of methods in molecular modeling in order to probe intricate biological problems. Many original and promising compounds have been identified and developed by integrating experimental and computational methods. Structural biology utilizes many different research techniques including x-ray crystallography, NMR, and electron microscopy in order to develop molecular models of macromolecules that are of biological interest. Such techniques can be used in conjunction with molecular docking, which utilizes those molecular models in order to target macromolecules of therapeutic interest by computationally analyzing the conformations adopted by ligands upon interaction with a desired …

Design And Implementation Of Degenerate Qpcr/Qrt-Pcr Primers To Detect Microbial Nitrogen Metabolism In Wastewater And Wastewater-Related Samples, Ryan F. Keeley

USF Tampa Graduate Theses and Dissertations

Nitrogen cycling processes can be tracked using quantitative Polymerase Chain Reaction (qPCR) to determine the presence and qReverse Transcriptase-PCR (qRT-PCR) to determine expression of key genes, or ‘biological markers’, for nitrogen metabolism. Nitrification is catalyzed in part, by two enzymes: ammonia monooxygenase (AMO; NH3 NH2OH) and nitrite oxidoreductase (NXR; NO2- NO3-). For denitrification, four enzymes act sequentially: nitrate reductase (NAR/NAP; NO3- NO2-), nitrite reductase (NIR; NO2- NO), nitric oxide reductase (NOR; NO  N2O), and nitrous oxide reductase (NOS; N2O  N2). A principle of wastewater treatment (WWT) is to remove excess nitrogen by taking advantage of natural nitrogen cycling …

A Small Rna And Dna Binding Protein Contribute To Biofilm Development In Bartonella Henselae, Udoka Okaro

USF Tampa Graduate Theses and Dissertations

A biofilm, which is associated with 80% of chronic infections in humans, is formed when bacteria aggregate, attach to a substrate and secrete a matrix protecting the bacteria from host cell defenses and antibiotics. Bartonella henselae (B. henselae) is the causative agent of cat scratch disease, persistent bacteremia, and one of the most frequently reported causes of blood-culture negative endocarditis (BCNE) in patients. The ability of B. henselae to adhere to the heart valve, form a biofilm and vegetation to cause endocarditis increases the morbidity and mortality rate in infected patients. The presence of a trimeric autotransporter adhesin (TAA) called …

Investigating The Proteinaceous Regulome Of The Acinetobacter Baumannii, Leila G. Casella

USF Tampa Graduate Theses and Dissertations

Acinetobacter baumannii is an opportunistic pathogen that overtime has evolved into one of the most problematic pathogens due to its ability to overcome antibiotic pressures and harshly environments in the host and hospital environments. In this context, its genomic evolution due to its capacity to acquire genes that contribute to its pathogenic and antibiotic resistance nature has been the subject of research in the last decades providing with the identification of several proteins aiding in the process of pathogenicity. Although these findings have contributed to our understanding of A. baumannii pathogenic traits, the regulatory network that control their expression are …

Evaluating Human-Associated Escherichia Coli Marker Genes For Microbial Source Tracking Applications In Florida, Jacob K. Senkbeil

USF Tampa Graduate Theses and Dissertations

Fecal pollution of surface water can lead to human health issues because waterborne transmission of pathogens is a common cause of gastroenteritis. Genetic markers developed for human-associated Escherichia coli (H8, H12, H14, and H24) are promising tools for microbial source tracking (MST) of sewage in environmental waterbodies but are untested in the US. H gene marker performance characteristics (specificity, sensitivity, and prevalence) were assessed, with the goal of developing a quantitative PCR assay for the markers with the best performance. Individual E. coli isolates from reference samples were tested to determine end-point PCR assay performance. Three hundred E. coli strains …

Microbial Associations Of Four Species Of Algal Symbiont-Bearing Foraminifera From The Florida Reef Tract, Usa, Makenna May Martin

USF Tampa Graduate Theses and Dissertations

Marine microbiome research is a rapidly expanding field of study, as scientists investigate the functions of microbial associations in eukaryotic organisms. Foraminifera are among the most abundant shelled organisms in the oceans, yet little is known of their associated microbiomes. This study investigated microbes associated with four species of Foraminifera that host three kinds of algal endosymbionts. The Order Miliolida, Family Soritidae, was represented by three species: Archaias angulatus and Cyclorbiculina compressa, which both host chlorophyte symbionts, and Sorites orbiculus, which hosts dinoflagellate symbionts. The fourth species, Amphistegina gibbosa, belongs to the Order Rotaliida and hosts diatom endosymbionts. Bacterial DNA …

Evaluation Of A Microsphere-Based Immunoassay (Mia) In Measuring Diagnostic And Prognostic Markers Of Dengue Virus Infection, Jason H. Ambrose

USF Tampa Graduate Theses and Dissertations

Infections with dengue viruses (DENV) constitute both a global problem as well as locally in Florida. DENV comprise four distinct serotypes of single-stranded RNA viruses and belong to the family Flaviviridae. DENV are among the most medically important arboviruses in the world and cases may currently exceed 400 million per annum. Additionally, dengue established its first recorded endemic transmission cycle in the state of Florida in over a half century, first within the Florida Keys during 2009-10 followed by an unrelated outbreak in Martin County in 2013. The clinical profile of DENV infections ranges from a mild febrile illness …

The Ecology Of Antibiotic Resistance: Sources And Persistence Of Vancomycin-Resistant Enterococci And Antibiotic Resistant Genes In Aquatic Environments, Suzanne M. Young

USF Tampa Graduate Theses and Dissertations

The growing crisis of antibiotic resistance is a major threat to ecosystems and human health. Infections caused by known and emerging antibiotic resistant pathogens are on the rise globally, with approximately 700,000 deaths per year caused by antibiotic resistant bacteria (1). In the United States, infections from antibiotic resistant bacteria cause more than 2 million illnesses and 23,000 deaths (2). Antibiotic resistant bacteria and antibiotic resistance genes are released into aquatic ecosystems through hospital waste, residential sewer lines and animal agricultural waste streams. Animal agriculture accounts for approximately 70% of antibiotic use in the United States (3). In agricultural ecosystems, …

Mechanism Elucidation And Inhibitor Discovery Against Serine And Metallo-Beta-Lactamases Involved In Bacterial Antibiotic Resistance, Orville A. Pemberton

USF Tampa Graduate Theses and Dissertations

The emergence and proliferation of Gram-negative bacteria expressing β-lactamases is a significant threat to human health. β-Lactamases are enzymes that degrade the β-lactam antibiotics (e.g., penicillins, cephalosporins, monobactams, and carbapenems) that we use to treat a diverse range of bacterial infections. Specifically, β-lactamases catalyze a hydrolysis reaction where the β-lactam ring common to all β-lactam antibiotics and responsible for their antibacterial activity, is opened, leaving an inactive drug. There are two groups of β-lactamases: serine enzymes that use an active site serine residue for β-lactam hydrolysis and metalloenzymes that use either one or two zinc ions for catalysis. Serine enzymes …

Packaging Of Genetic Material By Gene Transfer Agents (Gtas) Produced By Marine Roseobacter Species And Their Effect On Stimulating Bacterial Growth, Shahd Bader Aljandal

USF Tampa Graduate Theses and Dissertations

Horizontal gene transfer is one of the most important mechanisms for prokaryotic genome innovation and evolution. Gene Transfer Agents (GTAs) are phage-like particles that package small fragments of the genome of a GTA-producing bacterial cell. GTA chromosomal gene clusters usually contain 15-conserved open reading frames (ORFs) and are present in most of the sequenced marine alpha-proteobacteria genomes. Some marine strains have been shown to produce GTA particles that were biologically active in marine environment.

GTA particles range in size, morphology and the amount of host DNA they package. To date, the characteristics of GTAs are largely based on observations of …

Cell Division Regulation In Staphylococcus Aureus, Catherine M. Spanoudis

USF Tampa Graduate Theses and Dissertations

Cell division is a fundamental biological process that occurs in all kingdoms of life. Our understanding of cell division in bacteria stems from studies in the rod-shaped model organisms: Gram-negative Escherichia coli and Gram-positive Bacillus subtilis. The molecular underpinnings of cell division regulation in non-rod-shaped bacteria remain to be studied in detail. Rod-shaped bacteria possess many positive and negative regulatory proteins that are essential to the proper placement of the division septa and ultimately the production of two identical daughter cells, many of which are absent in cocci. Given that essential cell division proteins are attractive antibacterial drug targets, it …

Role Of Viruses Within Metaorganisms: Ciona Intestinalis As A Model System, Brittany A. Leigh

USF Tampa Graduate Theses and Dissertations

Marine animals live and thrive in a literal sea of microorganisms, yet are often able to maintain specific associations that are largely dictated by the environment, host immunity and microbial interactions. Animal-associated microbiomes include bacteria and viruses that vastly outnumber host cells, especially in the gut environment, and are considered to be integral parts of healthy, functioning animals that act as a metaorganism. However, the processes underlying the initial establishment of these microbial communities are not very well understood. This dissertation focuses on the establishment of a well-known developmental animal model, Ciona intestinalis (sea squirt), to study the establishment and …

Discovering Antibacterial And Anti-Resistance Agents Targeting Multi-Drug Resistant Eskape Pathogens, Renee Fleeman

USF Tampa Graduate Theses and Dissertations

Antibiotic resistance has been a developing problem for mankind in recent decades and multi-drug resistant bacteria are now encountered that are resistant to all treatment options available. In 2014, the World Health Organization announced that this problem is driving us towards a “post-antibiotic era” that will change the face of modern medicine as we know it. If lack of novel antibiotic development and FDA approval continues, by the year 2050, 10 million people will die each year to an antimicrobial resistant bacterial infection. With lack of pharmaceutical industry involvement in developing novel antibiotics, the responsibility now lies within the academic …

Non-Classical Regulators In Staphylococcus Aureus, Andy Weiss

USF Tampa Graduate Theses and Dissertations

Staphylococcus aureus is a highly problematic human pathogen due to its ability to cause devastating infections, paired with a capacity to withstand the action of a large fraction of available antibiotics. Both pathogenicity and antibiotic resistance are encoded by numerous genomic elements, though the expression of these factors is energetically costly and not always beneficial for cellular survival. Therefore, S. aureus has developed sophisticated regulatory networks to integrate a multitude of signals, enabling it to navigate the delicate balance between its pathogenic lifestyle and baseline needs for cellular energy homeostasis. It is thus imperative to study S. aureus behavior and …

A Novel Approach To The Discovery Of Natural Products From Actinobacteria, Rahmy Tawfik

USF Tampa Graduate Theses and Dissertations

Actinobacteria, primarily the genus Streptomyces, have led to the development of a number of antibiotics, which result from their secondary metabolites or modified derivatives. Secondary metabolite production can result from competition with neighboring microbes in an effort to disrupt growth, aiding in the competition for vital nutrients in impoverished conditions. Such secondary metabolites have the potential to affect a plethora of cellular functions in target cells, including, cell wall development, protein synthesis, protein function and fatty acid synthesis/metabolism. Due to the pandemic spread of antibiotic resistant bacteria, it is imperative to continue the search for new therapeutic agents …

A Novel Abi-Domain Protein Controls Virulence Determinant Production In Staphylococcus Aureus, Stephanie Michelle Marroquin

USF Tampa Graduate Theses and Dissertations

A major factor in the success of Staphylococcus aureus as a pathogen is its vast arsenal of virulence determinants and, more importantly, the tight and precisely- timed regulation of these factors. Here we investigate the product of the S. aureus gene, SAUSA300_1984, encoding a putative transmembrane protein. This as yet uncharacterized protein belongs to the Abi (abortive infection) family, which are commonly annotated as CAAX-proteases, and are significantly understudied in prokaryotes. In S. aureus the disruption of SAUSA300_1984 results in a drastic reduction of proteolytic and hemolytic activity, as well as diminished pigmentation. This phenotype appears to be mediated through …

Pepper Mild Mottle Virus As A Surrogate For Enteric Viruses: Implications For Assessing Water Quality, Erin Michelle Symonds

USF Tampa Graduate Theses and Dissertations

Less than 10% of the world’s domestic wastewater is disinfected prior to discharge into surface waters; therefore, human exposure to diverse wastewater-related pathogens results in millions of cases of illness each year. Among the enteric pathogens, viruses represent an important group of emerging pathogens and are frequently the cause of food- and water-borne outbreaks of illness. Although the World Health Organization and many government agencies mandate the use of bacterial indicators to identify poor microbial water quality, it is well known that these indicators poorly correlate with fecal pollution contamination events and risk of disease. The field of public health-related …

Antimalarial Exoerythrocytic Stage Drug Discovery And Resistance Studies, Lynn Dong Blake

USF Tampa Graduate Theses and Dissertations

Malaria is a devastating global health issue that affects approximately 200 million people yearly and over half a million deaths are caused by this parasitic protozoan disease. Most commercially available drugs only target the blood stage form of the parasite, but the only way to ensure proper elimination is to treat the exoerythrocytic stages of the parasite development cycle. There is a demand for the discovery of new liver stage antimalarial compounds as there are only two current FDA approved drugs for the treatment of liver stage parasites, one of which fails to eliminate dormant forms and the other inducing …

Monitoring And Mitigation Of Elevated Co2 Impacts Using Microalgae, Terry-Rene Wiesner Brown

USF Tampa Graduate Theses and Dissertations

Climate change is arguably the greatest environmental and economic challenge of our time. There are considerable documented and projected impacts to both human and natural systems as a result of climate change. These impacts include changes in temperature, sea level, precipitation patterns, and biogeography of ecologically and economically relevant species, including pathogens. One of the main drivers of climate change is elevated levels of atmospheric carbon dioxide (CO₂), a greenhouse gas. Since pre-industrial times, atmospheric CO₂ levels have increased from approximately 280 ppm to over 400 ppm, as a result of fossil fuel combustion, cement production and …

Reclaiming The Activity Of Lost Therapeutics, Rallya Telussa

USF Tampa Graduate Theses and Dissertations

ESKAPE pathogens are notorious in causing nosocomial infections and escaping current antibiotic treatments. There has been a dramatic increase in nosocomial infections accompanied with a decrease in the number of antibiotics developed, leading to significant increase in morbidity and mortality among patients. In an attempt to combat this problem, derivatives of ciprofloxacin, rifabutin and beta-lactam antibiotics were synthesized and tested against the ESKAPE pathogens. From minimum inhibitory concentration assays, 4 ciprofloxacin analogs and 8 beta-lactam analogs were found to be effective against multiple bacterial species. Additionally, 12 rifabutin analogs and 23 beta-lactam analogs were potent against single bacterial species, primarily …

Respiratory Syncytial Virus-Infected Mesenchymal Stem Cells Regulate Immunity Via Interferon-Beta And Indoleamine-2,3-Dioxygenase, Michael B. Cheung

USF Tampa Graduate Theses and Dissertations

Respiratory syncytial virus (RSV) is the most common cause of acute lower respiratory tract infection in young children worldwide, accounting for an estimated 33.8 million cases of respiratory disease, over 3 million of which require hospitalization, and between 66,000 and 199,000 deaths in this susceptible population. Additionally, severe RSV infection early in life is associated with an increased risk of wheeze and other airway disorders later in life. Despite this, there is currently no vaccine or economically reasonable prophylactic regimen to prevent infection. While disease is typically more severe in infancy RSV can infect throughout the lifespan repeatedly as the …

Investigation Of Respiratory Syncytial Virus Structural Determinants And Exploitation Of The Host Ubiquitin System, Jillian Nicole Whelan

USF Tampa Graduate Theses and Dissertations

Respiratory syncytial virus (RSV) is a globally circulating, non-segmented, negative sense (NNS) RNA virus that causes severe lower respiratory infections. This study explored several avenues to ultimately expand upon our understanding of RSV pathogenesis at the protein level. Evaluation of RSV intrinsic protein disorder increased the relatively limited description of the RSV structure-function relationship. Global proteomics analysis provided direction for further hypothesis-driven investigation of host pathways altered by RSV infection, specifically the interaction between the RSV NS2 protein and the host ubiquitin system. NS2 primarily acts to antagonize the innate immune system by targeting STAT2 for proteasomal degradation. The goal …

Characterization Of Bacterial Diversity In Cold-Water Anthothelidae Corals, Stephanie Nichole Lawler

USF Tampa Graduate Theses and Dissertations

Cold-water corals, similar to tropical corals, contain a diverse and complex microbial landscape. Comprised of vital microscopic organisms (i.e. bacteria, viruses, archaea), the coral microbiome is a driving factor in the proliferation and survival of the coral host. Bacteria provide essential biological functions within coral holobionts, facilitating increased nutrient utilization and production of antimicrobial compounds. To date, few cold-water octocoral species have been analyzed to explore the diversity and abundance of their microbial associates. For this study, 23 samples of the family Anthothelidae were collected from Norfolk (n = 12) and Baltimore Canyons (n = 11) from the western Atlantic …

Characterization Of Two Novel Gene Regulatory Systems In The Zoonotic Bacterium Bartonella Henselae, Nhan Tu

USF Tampa Graduate Theses and Dissertations

The genus Bartonella contains Gram-negative arthropod-borne bacteria that are found in many small animal reservoirs and are capable of causing human disease. Bacteria utilize a general stress response system to combat stresses from their surrounding environments. In α-proteobacteria, the general stress response system uses an alternate σ factor as the main regulator and incorporates it with a two-component system into a unique system. Our study identifies the general stress response system in the α-proteobacterium, Bartonella henselae, where the gene synteny is conserved and both the PhyR and alternate σ factor have similar sequence and domain structures with other α-proteobacteria. …

Pathogen Removal In Natural Wastewater Treatment And Resource Recovery Systems: Solutions For Small Cities In An Urbanizing World, Matthew Eric Verbyla

USF Tampa Graduate Theses and Dissertations

Sanitation, renewable energy, and food security are among the most pressing global development needs of the century, especially for small cities with rapid population growth. Currently, 53% of the world’s population either lacks access to improved sanitation or discharges fecal waste to the environment without treatment. Furthermore, 80% of food consumed in developing regions is produced by 500 million small farms, and while many of them are still rain-fed, irrigated agriculture is increasing. The post-2015 Sustainable Development Goals, recently adopted by the United Nations, include targets to address the water-energy-food nexus. Wastewater reuse in agriculture can be an important solution …