Transcriptome analysis of LuxS-deficient Streptococcus mutans grown in biofilms

• Published in: Molecular oral microbiology Vol. 26; no. 1; pp. 2 - 18
• Main Authors: Wen, Z.T., Nguyen, A.H., Bitoun, J.P., Abranches, J., Baker, H.V., Burne, R.A.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01-02-2011
• Subjects: Adenosine Triphosphatases - genetics; Adenosine Triphosphate - genetics; ATP; Bacterial Proteins - genetics; Bacteriological Techniques; Biofilms; Biofilms - growth & development; Carbon-Sulfur Lyases - genetics; Confocal microscopy; dental caries; DNA array analysis; DNA microarrays; DNA repair; DNA Repair - genetics; Down-Regulation; Energy metabolism; Enzymes; F-ATPase; Gene expression; Gene Expression Profiling - methods; Humans; Hydrogen Peroxide - pharmacology; Hydrogen-Ion Concentration; Image Processing, Computer-Assisted; Inoculation; LuxS protein; Microscopy, Confocal; Mutation; Mutation - genetics; Oligonucleotide Array Sequence Analysis; Operon - genetics; Operons; Oxidants - pharmacology; Oxidative stress; Oxidative Stress - genetics; pH effects; Phosphoenolpyruvate Sugar Phosphotransferase System - genetics; phosphotransferase; Proton Pumps - genetics; quorum sensing; Streptococcus mutans; Streptococcus mutans - enzymology; Transcription; Transcription, Genetic - genetics; Up-Regulation; Virulence; Virulence - genetics
• ISSN: 2041-1006; 2041-1014
• DOI: 10.1111/j.2041-1014.2010.00581.x

Summary
We previously reported that LuxS in Streptococcus mutans is involved in stress tolerance and biofilm formation. In this study, flowcells and confocal laser scanning microscopy were used to further examine the effects of LuxS‐deficiency on biofilm formation. Similar to the wild‐type strain (UA159), a strain deficient in LuxS (TW26D) bound efficiently to the flowcells and formed microcolonies 4 h after inoculation. Unlike UA159, which accumulated and formed compact, evenly distributed biofilms after 28 h, TW26D showed only loose, sporadic, thin biofilms. DNA microarray analysis revealed alterations in transcription of more than 60 genes in TW26D biofilms by at least 1.5‐fold (P < 0.001). Among the upregulated genes were those for sugar‐specific enzymes II of the phosphotransferase (PTS) system and the atp operon, which codes for the proton‐pumping F‐ATPase. Of the downregulated genes, several encode proteins with putative functions in DNA repair. Mutation of selected genes caused severe defects in the ability of the mutants to tolerate low pH and oxidative stress. These results provide additional proof that LuxS‐deficiency causes global alterations in the expression of genes central to biofilm formation and virulence of S. mutans, including those involved in energy metabolism, DNA repair and stress tolerance.