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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 …
Contribution Of A Class Ii Ribonucleotide Reductase To The Manganese Dependence Of Streptococcus Sanguinis, John L. Smith
Contribution Of A Class Ii Ribonucleotide Reductase To The Manganese Dependence Of Streptococcus Sanguinis, John L. Smith
Theses and Dissertations
Manganese-deficient Streptococcus sanguinis mutants exhibit a dramatic decrease in virulence for infective endocarditis and in aerobic growth in manganese-limited media. Loss of activity of a manganese-dependent, oxygen-dependent ribonucleotide reductase (RNR) could explain the decrease in virulence. When the genes encoding this RNR are deleted, there is no growth of the mutant in aerobic broth culture or in an animal model. Testing the contribution of the aerobic RNR to the phenotype of a manganese transporter mutant, a heterologous class II RNR from Lactobacillus leichmannii called NrdJ that requires B12 rather than manganese as a cofactor was previously introduced into an …
Systematic Analysis Of Abc Transporters In Streptococcus Sanguinis, Sawsan Atia
Systematic Analysis Of Abc Transporters In Streptococcus Sanguinis, Sawsan Atia
Theses and Dissertations
The bacterium Streptococcus sanguinis is a primary member of the human oral microflora and also has been recognized as a key player in the bacterial colonization of the mouth. It is considered the most common viridians streptococcal species implicated in infective endocarditis. In all kingdoms of life, ATP binding cassette (ABC) transporters are essential to many cellular functions. Sequencing of the SK36 genome provided the opportunity to study ABC transporter mutants and their relationship with acidity of the oral environment. Despite numerous studies that have focused on carbohydrate uptake systems in closely related streptococcal species such as S. mutans, S. …
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 …
Systematic Study Of Gene Functions For Morphological Chain Formation In Streptococcus Sanguinis, Karra Evans
Systematic Study Of Gene Functions For Morphological Chain Formation In Streptococcus Sanguinis, Karra Evans
Theses and Dissertations
Streptococcus sanguinis is a gram-positive facultative anaerobe that is indigenous to the oral cavity and a primary colonizer of the oral cavity. It serves as a tether for the attachment of several oral bacteria that colonize the tooth surface, form dental plaque, and cause periodontal disease. Previous experiments with streptococcal strains have suggested that cellular chain morphology of streptococci may influence the competitiveness, susceptibility to phagocytosis, acidurance, and aggregation of the bacterium. The purpose of this study was to systematically determine gene functions that contribute to cellular chain length morphology in the SK36 strain of S. sanguinis. Gene functions for …
Identification Of Virulence Determinants For Streptococcus Sanguinis Infective Endocarditis, Lauren Turner
Identification Of Virulence Determinants For Streptococcus Sanguinis Infective Endocarditis, Lauren Turner
Theses and Dissertations
Streptococcus sanguinis is the second most common causative agent of bacterial infective endocarditis (IE). Risk of S. sanguinis IE is dependent on pre-disposing damage to the heart valve endothelium, which results in deposition of clotting factors for formation of a sterile thrombus (referred to as vegetation). Despite medical advances, high mortality and morbidity rates persist. Molecular characterization of S. sanguinis virulence determinants may enable development of prevention methods. In a previous screen for S. sanguinis virulence determinants by signature-tagged mutagenesis (STM) an attenuated mutant was identified with a transposon insertion in the nrdD gene, encoding an anaerobic ribonucleotide reductase. Evaluation …
Physiological And Molecular Characterization Of Genetic Competence In Streptococcus Sanguinis, Alejandro Rodriguez
Physiological And Molecular Characterization Of Genetic Competence In Streptococcus Sanguinis, Alejandro Rodriguez
Theses and Dissertations
The ability of bacteria to assimilate free DNA from the environment is known as competence. Though many studies have focused on competence regulation in Streptococcus pneumoniae and Streptococcus gordonii, Streptococcus sanguinis has yet to be examined. Physiological characterization of competence in S. sanguinis strain SK36 and its comC mutant, JFP41, led to the genome-wide transcriptional analysis of cells induced to competence via addition of competence-stimulating peptide (CSP). A total of 128 genes were induced at least 2-fold, 74 of which were classified as either “early” or “late” based on their induction patterns. Expression patterns were verified using qRT-PCR. This study …