Life Sciences Commons^™

Breaking Virulent: The Coincidental Evolution Of Virulence Factors In Bacteria., Rhiannon Emmanuelle Cecil

Electronic Theses and Dissertations

Understanding how innocuous organisms can evolve to be pathogenic to humans is of increasing global concern. Further, understanding how existing pathogens may evolved to be more virulent is also vital to our ability to provide healthcare to people afflicted with diseases that promote chronic bacterial infections, such as cystic fibrosis. With the rise of antibiotic resistance in both bacteria and fungi it is paramount that new therapeutics are identified. Understanding what mutations occur that result in increased virulence in microbes can potentially provide new targets for antimicrobial drugs to combat antibiotic resistance. The Coincidental Evolution Hypothesis is a fundamental hypothesis …

Analyzing Pseudomonas Aeruginosa With Bacteriophage Tags Using Photoacoustic Flow Cytometry, Jennifer C. Schinke

Electronic Theses and Dissertations

The number of daily bacterial infections is climbing and the CDC explains that this is due to the antibiotic-resistant threat in the United States. Finding a faster way of bacterial identification is necessary as it currently takes 1-4 days for a medical lab to culture and identify bacteria. Photoacoustic flow cytometry (PAFC) can be used as an alternative method resulting in swift identification within an hour (Edgar, 2019). Pseudomonas aeruginosa, cell line PA01, will be coated in up to a few hundred red dyed phages making it detectible by the photoacoustic flow cytometry system. Bacteriophages (phages) are viruses that …

Use Of Transposon Screening For Salicylic Acid-Assisted Desiccation Killing In Salmonella, Shannon D. Elliott

Electronic Theses and Dissertations

Salmonella enterica serovar Typhimurium is one of the most prevalent food-borne pathogens, affecting millions around the world every year, making it a threat to global health. Salmonella possesses the ability to survive the normally lethal condition of desiccation, however, discovery of the genes and mechanisms behind this phenomenon are still ongoing. Using a transposon mutagenesis approach to construct a broad transposon library, this study aimed to uncover genes that may be contributing to changes in Salmonella’s survivability under desiccation, particularly when exposed to the antimicrobial molecule salicylic acid. Building on previous findings showing salicylic acid can alter cell viability …

Inhibiting Survival Of Salmonella During Desiccation Through The Use Of Naturally Occurring Signals, Joseph Headrick

Electronic Theses and Dissertations

A rising problem in agriculture is the increase of antibiotic-resistant Salmonella cases associated with chicken eggs, which transmit infection to humans. To counter this, new approaches to combat Salmonella in chickens and desiccated on eggshells are vital in the prevention of human foodborne illness. Disrupting signaling pathways with naturally occurring compounds provides a potential novel avenue for prevention of Salmonella infections, as this would disrupt sensing of these environments and inhibit subsequent optimal gene expression. Starting with signals identified in previous studies, salicylic acid was found to inhibit Salmonella desiccation survival on both eggshells and plastic. To expand upon this, …

The Stringent Response In Pseudomonas Aeruginosa Influences The Phenotypes Controlled By The Gac/Rsm System, Michael Shawn Hooker

Electronic Theses and Dissertations

Pseudomonas aeruginosa is a ubiquitous, opportunistic pathogen that causes acute and chronic infections. Infection is typically initiated via motile and virulent strains. After exposure to stressors, acute infections make both genotypic and phenotypic switches to a chronic, sessile strain. This is due to intricate regulatory networks directing gene expression in response to stressors. One network, GacA/GacS, has been established to control virulence factors. The stringent response of bacteria is mediated by alarmones produced primarily by RelA which responds to starvation.

To study the effect of the stringent response on the virulence switch. A series of experiments were run in both …

Indigenous Toxin Affects Cell Viability, While An Artificial Proteolytic Queueing Causes The Upregulation Of Specific Genes, Mohammed Salahuddin

Electronic Theses and Dissertations

Studying bacterial physiology is crucial to understand the fundamental mechanisms that govern bacterial growth, survival, and adaptation. This thesis combines two chapters investigating bacterial physiology by studying important cellular processes like bacterial toxin-antitoxin systems and proteolytic pathways. The first chapter involves studying bacterial toxin-antitoxin systems to understand the regulation and function of hypothetical toxin-antitoxin (TA) systems of bacteria and the effects of these TA systems on bacterial growth and survival. The emergence of these genetic modules in bacterial research and the unrevealing of some of their important roles in cell physiology in recent years has drawn much attention in scientific …