DOI
https://doi.org/10.25772/BJ1T-KG18
Defense Date
2017
Document Type
Thesis
Degree Name
Master of Science
Department
Microbiology & Immunology
First Advisor
Dr. Todd Kitten
Second Advisor
Dr. Kimberly Jefferson
Third Advisor
Dr. Darrell Peterson
Abstract
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 RNR mutant of S. sanguinis. Aerobic growth was only partially restored. Currently, we sought to improve NrdJ-dependent growth by (i) amending the medium to increase cellular levels of B12; (ii) characterizing a spontaneous mutant of the NrdJ-complemented strain with improved aerobic growth; and (iii) altering this strain through further genetic manipulation.
Rights
© John Lee Smith
Is Part Of
VCU University Archives
Is Part Of
VCU Theses and Dissertations
Date of Submission
6-27-2017