Fig. 1.

S. mutans and L. casei in dual-species cultures displayed altered survival rates as compared to those grown alone, when subjected to acid- (a) and hydrogen-peroxide- (b) killing assays. For acid-killing assays, L. casei was incubated in 0.1 M glycine buffer, pH 2.0 for periods as indicated, and S. mutans was incubated in buffer of pH 2.8 for the same periods. For hydrogen-peroxide-killing assays, S. mutans and L. casei were incubated in glycine buffer containing 0.2% hydrogen peroxide. *, P<0.001 vs the respective mono-species cultures. (From Wen et al., 2017. Front. Cell. Infect. Microbiol. 7 : 524. doi: 10.3389/fcimb.2017.00524).