Journal: Journal of Bacteriology
Article Title: Streptococcal Antagonism in Oral Biofilms: Streptococcus sanguinis and Streptococcus gordonii Interference with Streptococcus mutans
Figure Lengend Snippet: Inhibition ability and competitiveness of wild-type and Pox − mutant of S. sanguinis and S. gordonii . (A) S. sanguinis or S. gordonii or their derivatives were inoculated first and incubated aerobically at 37°C. S. mutans was inoculated 16 h later, and the plates were incubated overnight. a, SK36; b, JKH2 Pox − ; c, JKH2/pDL276-pox; d, DL1; e, JKH1 Pox − ; f, JKH1/pDL276-pox. (B) Growth of S. mutans in sterile conditioned medium from S. sanguinis or S. gordonii cultures. The conditioned medium was prepared from exponentially growing S. sanguinis or S. gordonii cells or their derivatives, filter sterilized, supplemented with 0.25% glucose, and immediately inoculated with S. mutans at a titer of 10 7 bacteria ml −1 . Cells were incubated aerobically at 37°C, and 1 ml was removed to determine the A 600 at the indicated time points. The data presented are representative of two independent experiments with similar results. (C) Competitiveness of S. sanguinis or S. gordonii wild-type and Pox − mutants in submerged dual-species biofilms with S. mutans . Dual-species biofilms were grown in BHI. After overnight growth, the cells were dispersed by vigorous pipetting, serially diluted, and plated. The CFU values for each strain and the standard deviations were calculated from three independent experiments performed on different days. *, P ≤ 0.05. Gray bars, S. sanguinis or S. gordonii ; black line, S. mutans .
Article Snippet: For competition assays in liquid media, cells were grown in BHI medium overnight, and either S. sanguinis or S. gordonii (15 μl of each) and S. mutans (15 μl) was inoculated simultaneously into 1 ml of fresh BHI (supplemented with 1% glucose when indicated) in a Costar 24-well cell culture cluster (Corning, Inc., Corning, NY) for biofilm growth.
Techniques: Inhibition, Mutagenesis, Incubation