Fig. 5

Example images of LIVE/DEAD® BacLight™ stained cells of S. gordonii CW and A. naeslundii CW viewed with CLSM. Control cells were kept at pH 7.5 and then exposed to acid challenge (pH 3.5). For ATR induction, cells were exposed to an adaptation pH (pH 5.5) for 2 h prior to exposure to pH 3.5. Viable cells (acid tolerant) appear green while dead cells (non-acid tolerant) appear red. Scale bar shows 20 μm