Morphological and proteomic analyses of the biofilms generated by Streptococcus mutans isolated from caries-active and caries-free adults

Abstract

Background/purpose: Biofilm formation by Streptococcus mutans is a prerequisite for the development of caries. Different strains of S. mutans may differ in their capacity in biofilm formation and protein expression. The objective of this study was to investigate the morphological features and proteomes of biofilms of S. mutans clinical isolates. Materials and methods: Clinical strains isolated from caries-active (SM 593) and caries-free (SM 18) adults were cultured on polystyrene sheets in tryptoneepolypeptoneeyeast extract medium. Biofilm formation and structure were assessed by confocal laser scanning microscopy and scanning electron microscopy. Proteins were extracted from SM 593 and SM 18 presented in biofilms and separated with two-dimensional gel electrophoresis, followed by peptide mass fingerprinting using matrix-assisted laser desorption time-of-flight mass spectrometry analysis. Results: Initially detected 2 hours after incubation, biofilm formation reached its maximum level at 20 hours. The biofilm formed by SM 593 was thicker with a higher percentage of viable bacteria compared with that formed by SM 18. Hydrolase and pantothenate kinase were detected in the SM 593 biofilm only, whereas 6-pyruvoyl tetrahydropterin synthase and phosphoribosylglycinamide formyltransferase were expressed exclusively in the SM 18 biofilm. Expressions of D-alanyl-D-alanine carboxypeptidase and response regulator homolog of RumR were most greatly enhanced in the SM 593 and SM 18 biofilms, respectively.Conclusion: SM 593 exhibited greater biofilm-forming capacity compared to SM 18. SM 593 and SM 18 biofilms expressed specific proteins involved in nucleic acid metabolism and intermediary metabolism, respectively, which may account for the differences in their biofilmforming abilities.

FLO Genes Family and Transcription Factor MIG1 Regulate Saccharomyces cerevisiae Biofilm Formation During Immobilized Fermentation

“…This same expression pattern between MIG1 and the FLO1, 5 , and 9 genes was observed in biofilm formation, suggesting these FLO genes were regulated by MIG1 . Mature biofilms were divided into three parts: the outer, intermediate, and inner surface layers ( Jiang et al, 2015 ). Although cells-surface adhesion is a primary step in biofilm formation and critical for forming the inner biofilm layer ( Periasamy et al, 2012 ), cell–cell adhesions appeared more requisite in the intermediate and outer layers.…”

Effect of the Biofilm Age and Starvation on Acid Tolerance of Biofilm Formed by Streptococcus mutans Isolated from Caries-Active and Caries-Free Adults

“…Biofilm was proposed to play a crucial role in acid tolerant of S. mutans [ 34 ]. In our previous study, we also found that SM593 exhibited a superior capacity to form more complex biofilm than SM18 and ATCC 25175 [ 35 ]. Therefore, we speculate that more complex structure of biofilm and greater ability of SM593 to form biofilm could partly explain a stronger capability of SM593 biofilm to tolerate low pH and grow compared with SM18 biofilm and ATCC 25175.…”

Salivary protein roles in oral health and as predictors of caries risk

“…mutans strains with dental caries. In fact, the authors discovered significant differences in their abilities to form biofilms and in their profiles of protein expression [ 57 ].…”