IADR Abstract Archives
Does TasA protein play a role in co-species biofilm formation?
Objectives: Biofilm formation represents the first and main step in the development and progression of the majority of oral disorders. In the oral cavity, biofilm contains large number of genetically distinct microorganisms. Most bacteria are not pathogenic but can affect the biofilm virulence. In fact, accumulation of Bacillus subtilis might affect the oral eco-system due to interaction with the major cariogenic bacterium Streptococcus mutans. Therefore, we aimed investigating B. subtilis and S. mutans interrelationship.
Methods: Visualization of mono and co-species biofilm by S. mutans and B. subtilis was performed using SEM. Single cell force spectroscopy was done in order to determine the initial interaction forces between the bacteria and the role of TasA protein. Further investigation of the role of tasA on the incorporation of B. subtilis in the co-species biofilm was conducted using CLSM and qPCR. Finally, we examined the regulation of tasA in the presence of S. mutans.
Results: SEM visualization showed that dual biofilm has a more complex structure than that of the mono-species biofilm. Moreover, it indicated a tight interaction between B. subtilis' rod shaped cells and S. mutans' cocci-shaped cells. B. subtilis cells showed 5-fold higher adhesion force to S. mutans biofilm compared to glass or B. subtilis biofilm. In contrast to the WT, ΔtasA cells showed very weak interaction with S. mutans biofilm. Furthermore, CLSM pictures showed that B. subtilis cells appear in deeper layers of the biofilm and are surrounded by the EPS associated with S. mutans' dextran. The amount of ΔtasA cells was notably reduced in the dual biofilm compared to WT B. subtilis. Finally, we found that S. mutans upregulates tasA expression, partially due to pH changes.
Conclusions: Overall, our results suggest that the interactions between B. subtilis TasA protein and S. mutans' EPS govern the ability to form co-species biofilm.
Methods: Visualization of mono and co-species biofilm by S. mutans and B. subtilis was performed using SEM. Single cell force spectroscopy was done in order to determine the initial interaction forces between the bacteria and the role of TasA protein. Further investigation of the role of tasA on the incorporation of B. subtilis in the co-species biofilm was conducted using CLSM and qPCR. Finally, we examined the regulation of tasA in the presence of S. mutans.
Results: SEM visualization showed that dual biofilm has a more complex structure than that of the mono-species biofilm. Moreover, it indicated a tight interaction between B. subtilis' rod shaped cells and S. mutans' cocci-shaped cells. B. subtilis cells showed 5-fold higher adhesion force to S. mutans biofilm compared to glass or B. subtilis biofilm. In contrast to the WT, ΔtasA cells showed very weak interaction with S. mutans biofilm. Furthermore, CLSM pictures showed that B. subtilis cells appear in deeper layers of the biofilm and are surrounded by the EPS associated with S. mutans' dextran. The amount of ΔtasA cells was notably reduced in the dual biofilm compared to WT B. subtilis. Finally, we found that S. mutans upregulates tasA expression, partially due to pH changes.
Conclusions: Overall, our results suggest that the interactions between B. subtilis TasA protein and S. mutans' EPS govern the ability to form co-species biofilm.