IADR Abstract Archives
Gene Expression of Biofilm-forming Rothia mucilaginosa Isolated From Apical Periodontitis
Objectives: Rothia mucilaginosa is a gram-positive, coagulase-negative, non-spore-forming coccus which is considered as a part of the commensal flora of the oral cavity and the upper respiratory tract in humans. A biofilm-forming R. mucilaginosa strain designated as DY-18 was previously isolated from a persistent periapical periodontitis lesion. The ability to form a biofilm is one of the important factors that may allow bacteria to survive in the apical part of the root canal. To identify genes relating to biofilm formation, a gene expression pattern of DY-18 in the biofilm mode (static culture condition) was compared to that in the planktonic mode (dynamic culture condition).
Methods: For microarray-based gene expression profiling, perfect-matched 60 mer probes were designed from all the 1992 putative open reading frames of DY-18, which are available from the GenBank sequence database (accession number NC_013715). Gene expression profiles of DY-18 in the biofilm mode were compared to those grown in the planktonic mode. When the expression ratio was different by 1.2 fold, the expression of the gene was interpreted to be significantly up- or down-regulated.
Results: High viscosity of spent culture medium obtained from the static culture indicated that DY-18 produces large amounts of exopolysaccharides and forms biofilms. In contrast, the low viscosity observed in the dynamic culture was correlated with the planktonic mode of growth of this strain. Comparative microarray analyses indicated that the expression of genes encoding DNA polymerase III subunit beta, signal transduction histidine kinase, and molecular chaperone were significantly up-regulated in the biofilm mode. Moreover, bioinformatic analysis showed that these genes have domains relating to stress response, which has been shown to be regulators of biofilm formation in other bacteria.
Conclusions: The results suggest that these genes might contribute to exopolysaccharide production and biofilm formation of DY-18.
Methods: For microarray-based gene expression profiling, perfect-matched 60 mer probes were designed from all the 1992 putative open reading frames of DY-18, which are available from the GenBank sequence database (accession number NC_013715). Gene expression profiles of DY-18 in the biofilm mode were compared to those grown in the planktonic mode. When the expression ratio was different by 1.2 fold, the expression of the gene was interpreted to be significantly up- or down-regulated.
Results: High viscosity of spent culture medium obtained from the static culture indicated that DY-18 produces large amounts of exopolysaccharides and forms biofilms. In contrast, the low viscosity observed in the dynamic culture was correlated with the planktonic mode of growth of this strain. Comparative microarray analyses indicated that the expression of genes encoding DNA polymerase III subunit beta, signal transduction histidine kinase, and molecular chaperone were significantly up-regulated in the biofilm mode. Moreover, bioinformatic analysis showed that these genes have domains relating to stress response, which has been shown to be regulators of biofilm formation in other bacteria.
Conclusions: The results suggest that these genes might contribute to exopolysaccharide production and biofilm formation of DY-18.