FIG 7.

V. parvula enhances the health of S. mutans biofilms. S. mutans biofilms with or without V. parvula were initiated with cultures at an OD₆₀₀ of 1.0 and grown for 24 h in artificial saliva with 0.5% sucrose. Biofilms were stained with SYTO 9 (green, live) and propidium iodide (red, dead) for LIVE/DEAD staining followed by fluorescence microscopy (A to D) or LIVE/DEAD ratio measurements in a plate reader (F). (E) pH levels from both microscope slide wells and 24-well plates were measured. As a control for dead cells, Listerine Naturals was used to kill biofilms for 10 min prior to imaging. The pH for individual wells used for imaging are shown as inserts to the image. (A to D) Shown are images from the same day, representative of results from 3 different days. pH measurements constitute measurements averaged from 16 wells over 8 experiments. (E) *, P < 0.01 relative to S. mutans 25175; **, P < 0.01 relative to S. mutans 25175 with V. parvula 10790 by Student’s t test. (F) *, P < 0.01 relative to S. mutans 25175; **, P < 0.01 relative to S. mutans 25175 or S. mutans 25175 with V. parvula 10790 without Listerine by Student’s t test.