Signals of the pHluorin-SpaP fusion protein and metabolic activities of <i>S. mutans</i> in biofilms after addition of sucrose.

<p>(A) CLSM image showing pH heterogeneity of different microcolonies (indicated by arrows) within <i>S. mutans</i> biofilm in the presence of sucrose. Biofilms were revealed with CellTracker Orange. CellTracker Orange (blue), GFP (green) and the corresponding overly images are shown. (B) CLSM images showing differences in metabolic activities of microcolonies within <i>S. mutans</i> biofilm after addition of sucrose. (a) CLSM analysis of pHluorin signals of <i>S. mutans</i> strain O87 biofilm after addition of 2% sucrose for 60 min. Bars represent 50 µm. (b) 3D surface plot of fluorescence intensities of pHluorin (green) and the fluorescent metabolic indicator dye 5-Cyano-2,3-ditolyl tetrazolium chloride (CTC - red) in strain O87 biofilm after addition of 2% sucrose for 60 min. (c) and (d) The representative CLSM images of microcolonies within the same biofilm. Bars represent 20 µm.