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Examination Of Strain-Dependent Differences In S. Sanguinis Virulence And Growth, Shannon Baker
Examination Of Strain-Dependent Differences In S. Sanguinis Virulence And Growth, Shannon Baker
Theses and Dissertations
Streptococcus sanguinis, an abundant and benign inhabitant of the oral cavity, is an important etiologic agent of infective endocarditis, particularly in people with pre-disposing cardiac valvular damage. Although commonly isolated from patients with IE, little is known about the factors that make any particular S. sanguinis isolate more virulent than another or, indeed, whether significant differences in virulence exist among isolates. To investigate the virulence of multiple isolates, a variation of the Bar-seq (barcode sequencing) method was employed. A conserved chromosomal site was identified for subsequent insertion of a barcode identifier, unique for each strain. Barcode insertion did not …
Investigation Into The Role Of Manganese In The Growth Of The Opportunistic Pathogen Streptococcus Sanguinis, Brittany Spivey
Investigation Into The Role Of Manganese In The Growth Of The Opportunistic Pathogen Streptococcus Sanguinis, Brittany Spivey
Auctus: The Journal of Undergraduate Research and Creative Scholarship
While Streptococcus sanguinis plays a beneficial role in the oral cavity as a competitor of Streptococcus mutans and Streptococcus sobrinus, the bacteria that produce dental caries, it can cause deadly infective endocarditis if given the opportunity to colonize the vegetations that form over damaged endocardial tissue. Pre-existing heart conditions, surgery, and intravenous drug use predispose individuals to endocarditis. S. sanguinis growth and consequential virulence is significantly impeded by restriction to manganese. This is due to the resulting overwhelming oxidative stress and formation of reactive oxygen species which damage DNA and other cellular components. Manganese is essential for S. sanguinis proteins …
Involvement Of Signal Peptidase I In Streptococcus Sanguinis Biofilm Formation, Jessica Aynapudi
Involvement Of Signal Peptidase I In Streptococcus Sanguinis Biofilm Formation, Jessica Aynapudi
Theses and Dissertations
Biofilm accounts for 65%-80% of microbial infections in humans. Considerable evidence links biofilm formation to oral disease and consequently systemic infections. Eradication of biofilm-associated infections is important. Streptococcus sanguinis, a Gram-positive bacterium, is one of the most abundant species in oral biofilm. It contributes to biofilm development in oral cavities and is one of the recognized causes of infective endocarditis. To study and identify biofilm genes in S. sanguinis, biofilm formation of 51 mutants was compared with the wild type SK36 strain using crystal violet (CV) staining in a microtiter plate. Confocal laser scanning microscopy (CLSM) and image analysis was …
Functional Characterization Of The Streptococcus Sanguinis Com Regulon, Jill Callahan
Functional Characterization Of The Streptococcus Sanguinis Com Regulon, Jill Callahan
Theses and Dissertations
Streptococcus sanguinis is an important component of the dental plaque biofilm and is believed to play a beneficial role in the oral cavity. S. sanguinis is also a leading cause of infective endocarditis (IE), a potentially lethal infection of the cardiac valves. S. sanguinis possesses genetic competence, the ability to acquire exogenous DNA into its genome. In the well characterized system of S. pneumoniae, genetic competence requires a quorum sensing system encoded by the early comCDE genes, as well as late genes controlled by the alternate sigma factor, ComX. Previous studies in other streptococcal species have suggested functions for the …
Role Of Two-Component System Response Regulators In Virulence Of Streptococcus Pneumoniae Tigr4 In Infective Endocarditis, My Trinh
Theses and Dissertations
Streptococci resident in the oral cavity have been linked to infective endocarditis (IE). While viridans streptococci are commonly studied and associated with IE, less research has been focused on Streptococcus pneumoniae. Two-component systems (TCSs), consisting of a histidine kinase (HK) protein and response regulator (RR) protein, are bacterial signaling systems that may mediate S. pneumoniae TIGR4 strain virulence in IE. To test this hypothesis, TCS RR mutants of TIGR4 were examined in vivo through use of rabbit models. There were 14 RR proteins identified and 13 RR mutants synthesized because SP_1227 was found to be essential. The requirement of the …