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Theses and Dissertations

2011

Endocarditis

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Full-Text Articles in Medicine and Health Sciences

Functional Characterization Of The Streptococcus Sanguinis Com Regulon, Jill Callahan Jul 2011

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 Apr 2011

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 …