Kareena Raybuck
Research Mentor: Ryan Wyllie
Mentor Department: Biomedical Engineering, Engineering
Author(s): Kareena Raybuck, Ryan Wyllie
Session: Session 5 (2:00 PM – 2:50 PM)
Presentation Type: Poster 90
Abstract
Quorum-sensing systems enable microbes to respond to environmental changes. In the oral streptococci, quorum-sensing systems regulate the production of bacteriocins, potent antimicrobials with a high dysbiotic potential. As dysbiosis of the oral microbiome is implicated in several diseases, including dental caries, characterization of these quorum-sensing systems and their regulated bacteriocins is of great clinical importance. Unfortunately, the quorum-sensing landscape of the oral streptococci remains largely unmapped and unstudied. This is especially the case with regards to commensal oral streptococci, like Streptococcus sanguinis. S. sanguinis is a prominent early colonizer of the oral cavity and a key antagonist of pathogens such as S. mutans. Understanding quorum-sensing systems in S. sanguinis is therefore critical for explaining how beneficial bacteria shape oral microbial community structure and suppress pathogenic dominance. We identified a previously uncharacterized RtgRS-family quorum-sensing system in S. sanguinis and demonstrated that this system is activated by a short peptide pheromone in a dose-dependent manner. Furthermore, we show that pheromone-induced activation of the S. sanguinis RtgRS system leads to the expression of bacteriocin genes with antagonistic potential against other oral microbes. These findings reveal how S. sanguinis coordinates bacteriocin production and competitive behaviors to maintain a balanced oral microbiome and protect against dental caries. More broadly, this work provides insight into how microbial interactions can be modulated to prevent and manage dental diseases.
