Steps to Elucidating the Competence Regulon Quorum Sensing Mechanism in Streptococcus intermedius
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Authors
Anderson, Jenelle
Issue Date
2025
Type
Thesis
Language
en_US
Keywords
Alternative Title
Abstract
Quorum sensing (QS) is a cell-to-cell communication system used to modulate gene expression and coordinate group behavior based on cell density. Bacteria that utilize QS secrete chemical signal molecules known as autoinducers (AIs) that will accumulate as the cells continue to divide. The cells are able to determine cell density and coordinate these group behaviors such as virulence factors, biofilm formation, and activation of competence based on the environmental concentration of AIs. Due to this, QS could be used as a novel therapeutic strategy controlling infection rates without the use of antibiotics. Although highly effective, antibiotics pose a critical health threat due to the selective pressure they pose and that result in the development of resistant strains. The economic burden resulting from treating a multi-drug resistant (MDR) infection has cost healthcare systems millions of dollars. Streptococcus intermedius is an opportunistic pathogen that appears to possess a typical comABCDE competence regulon QS circuity. In this work I set out to study the S. intermedius competence regulon QS circuitry through the creation of a cell-based reporter system. To this end, a synthetic competence stimulating peptide (CSP) was synthesized and utilized to transform an antibiotic-resistant plasmid into the bacteria. Obtaining such reporter system would allow for structure-activity relationship studies of the CSP to be conducted and consequently the development of inhibitory AI analogs that could be utilized to attenuate S. intermedius pathogenic behaviors as an alternative method to treating infections while reducing the selective pressure to develop resistance.