Microbiology Commons^™

Pleiotropic Regulatory Function Of The Lysr Family Transcriptional Regulator Cpsy During Streptococcus Iniae Systemic Infection, Jonathan Paul Allen

Wayne State University Dissertations

The ability of a pathogen to metabolically adapt to the local environment for optimal expression of virulence determinants is a continued area of research. Orthologs of the Streptococcus iniae LysR family regulator CpsY have been shown to regulate methionine biosynthesis and uptake pathways, but appear to influence expression of several virulence genes as well. A S. iniae mutant with an in-frame deletion of cpsY is highly attenuated in a zebrafish infection model. The cpsY deletion mutant displays a methionine-independent growth defect in serum, which differs from the methionine-dependent defect observed for orthologous mutants of S. mutans and S. agalactiae. …

Identification Of The Role Of The Sal Locus In Streptococcus Pyogenes Virulence During Host-Pathogen Interactions, Phanramphoei Namprachan-Frantz

Wayne State University Dissertations

The pathogenesis of Streptococcus pyogenes is due to its ability to overcome and adapt to the harsh environment created by the host immune response. The focus of this project was the SalKR two-component regulatory system, which facilitates bacterial adaptation by responding to environmental signals during host pathogen-interactions. The first goal of this project was to determine a role in virulence for the SalKR regulatory system. The complete deletion of the salKR genes in the wild type S. pyogenes strain HSC5 produced a highly attenuated mutant in a Zebrafish infection model. The ΔsalKR mutant appeared to lose the ability to survive …

Analysis Of The Streptococcal Cpsa Protein In Dna-Binding And Regulation Of Capsule And Cell Wall Maintenance, Brett R. Hanson

Wayne State University Dissertations

The systemic pathogens Streptococcus agalactiae (GBS) and Streptococcus pneumoniae remain a significant threat to human health worldwide. The ability of these organisms to cause systemic disease is compounded by the production of a polysaccharide capsule that provides immune evasion function. The production of the polysaccharide capsule in systemic streptococcal pathogens is controlled in part by the membrane bound protein CpsA. These studies analyze the contribution of CpsA to regulation of capsule level in the model aquatic pathogen Streptococcus iniae and human specific pathogen GBS, and how this regulation affects virulence in in-vitro, ex-vivo, and in-vivo models of pathogenesis. We have …

Laser-Induced Breakdown Spectroscopy (Libs): An Innovative Tool For Studying Bacteria, Qassem I. Mohaidat

Wayne State University Dissertations

Laser-induced breakdown spectroscopy (LIBS) has gained a reputation as a flexible and convenient technique for rapidly determining the elemental composition of samples with minimal or no sample preparation. In this dissertation, I will describe the benefits of using LIBS for the rapid discrimination and identification of bacteria (both pathogenic and non-pathogenic) based on the relative concentration of trace inorganic elements such as Mg, P, Ca, and Na. The speed, portability, and robustness of the technique suggest that LIBS may be applicable as a rapid point-of-care medical diagnostic technology.

LIBS spectra of multiple genera of bacteria such as Escherichia, Streptococcus, Mycobacterium, …