FIG 5.

Expression of a hypothetical protein upstream of pcfV is upregulated in the absence of pcfV. (A) Levels of expression of peg.1179 mRNA were compared using qRT-PCR in a pcfV deletion strain of A12 and the wild type. Overnight cultures were inoculated into fresh BHI medium. When cultures reached an OD₆₀₀ of 0.5, cells were collected for RNA extraction and subsequent qRT-PCR. (B) Plate-based growth inhibition of A12 strains versus S. mutans. All bacterial cultures were grown overnight in BHI medium and then adjusted to an OD₆₀₀ of 0.5 with fresh BHI. Aliquots (6 μl) from A12 or A12 mutant derivatives were spotted first, followed by spotting of S. mutans 24 h later. Plates were incubated for 48 h at 37°C in a 5% CO₂ aerobic atmosphere. (C) Expression of pcfV of A12 was assessed using qRT-PCR in a peg.1179 deletion A12 strain and in the wild-type strain. All experiments were done in biological triplicates with technical triplicates, and error bars represent SDs. Statistical analysis was performed using an unpaired Student t test. ***, P < 0.001.