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- Robertsson, Carolina, 1993-
(author)
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Responses to External Cues in Oral Bacteria
- 2023
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Doctoral thesis (other academic/artistic)abstract
- This thesis investigates responses to external cues in oral bacteria on a molecular level. Paper I maps Ser/Thr/Tyr phosphorylated proteins in relation to the general proteome in an oral commensal streptococcus (Streptococcus gordonii DL1). The identified phosphoproteins were involved in various bacterial processes, several associated to dysbiosis and development of biofilm-induced disease. Comparison against phosphoproteomes of other bacteria showed many similarities. This is of interest for the identification of shared phosphorylation profiles. Paper II studies differences between the S. gordonii DL1 general proteomes in planktonic and biofilm growth phases, and the regulatory effects of salivary mucin MUC5B on protein expression in the biofilm cells. Regulations in protein expression between the different growth conditions provides insights in bacterial mechanisms for adaptation to the biofilm lifestyle. Paper III examines the regulatory roles of salivary MUC5B on biofilm attachment and metabolic output in two clinical isolates of oral commensals, S. gordonii CW and Actinomyces naeslundii CW. S. gordonii facilitated adhesion of A. naeslundii to MUC5B during early attachment. Both bacteria were also able to utilize MUC5B as a sole nutrient source during early biofilm formation, individually and synergistically in a dual species biofilm. The specific responses elicited by MUC5B in paper II-III seem to promote commensal colonization while down-regulating dysbiosis-related biofilm activities. Microbiological studies are often focused on dysbiosis and development of disease. However, mechanisms that promote eubiosis are equally important to understand how health can be maintained. Findings associated with responses to external cues in oral bacteria may contribute to future development of novel preventative strategies and identification of predictive biomarkers for oral health.
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