Defense Date
2026
Document Type
Thesis
Degree Name
Master of Science
Department
Microbiology & Immunology
First Advisor
Dr. Daniel Miller
Abstract
Selenomonas sputigena is an obligate anaerobic, Gram-negative pathobiont that transitions from a low-abundance commensal bacteria to a structural component in dysbiotic oral biofilms associated with early childhood caries and periodontitis. Analysis of S. sputigena ATCC 35185 cultures optimized in TYGVS media revealed robust growth, characteristic crescent morphology with flagellar tuft motility, and strong monospecies biofilm formation comparable to Streptococcus mutans via crystal violet assays.
ELISA quantification demonstrated significantly elevated c-di-GMP levels in sessile biofilm fractions relative to motile planktonic cells (p=0.0009), establishing the secondary messenger’s correlation with the motile-sessile lifestyle switch. Recombinant expression and purification yielded PilZ-domain effector proteins, Selsp_1666 and Selsp_1678, while candidate diguanylate cyclases selsp_0085, selsp_0682, and selsp_2272 proved recalcitrant to soluble expression.
These findings demonstrate c-di-GMP production in S. sputigena for the first time and implicate the signaling axis in pathobiont biofilm persistence within polymicrobial caries and periodontal lesions. The inability to reproduce genetic manipulation underscores the need for refined transformation protocols to dissect pathway components and evaluate therapeutic vulnerabilities.
Rights
© The Author
Is Part Of
VCU University Archives
Is Part Of
VCU Theses and Dissertations
Date of Submission
5-4-2026