Defense Date


Document Type


Degree Name

Master of Science


Microbiology & Immunology

First Advisor

Ping Xu


The gram-positive bacterium Streptococcus sanguinis is a member of human indigenous oral microbialflora and has long been recognized as a key player in the bacterial colonization of the mouth. S. sanguinis is also the most common viridians streptococcal species implicated in infective endocarditis. Although many studies have focused on two-component systems in closely related Streptococcus species such as S. mutans, S. pneumoniae and S. gordonii; the mechanism of the response regulator in S. sanguinis is still unknown. The ability of S. sanguinis to adapt and thrive in hostile environments suggests this bacterium is capable of sensing and responding to various environmental stimuli. The present study clearly demonstrates that a number of RR genes, SSA_0204, SSA_0217, SSA_1810, SSA_1794, and SSA_1842, in S. sanguinis are essential to the recognition and response to various environmental stresses. Results from this study also identified genes SSA_0260, SSA_0261, and SSA-0262, involved in acidic tolerance and suppressed by SSA_0204 response regulator.


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Is Part Of

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Is Part Of

VCU Theses and Dissertations

Date of Submission

September 2010