FIG. 5.

S. mutans bacteriocin gene expression in mixed cultures. Total RNA from S. mutans BM71 alone or in a mixture with S. gordonii or from S. mutans BM71 comC mutant cells was isolated from broth cultures in THBY (OD₆₀₀ readings of 1.0 to 1.2). Reverse transcription-PCR products were electrophoresed in 2% agarose gels and demonstrated bands of 274, 357, and 482 bp for the smbAB, smbM1, and ftf genes, respectively. Lanes: 1, S. mutans BM71; 2, S. mutans BM71 comC mutant, 3, S. mutans BM71 mixed with S. gordonii Challis; 4, S. mutans BM71 mixed with S. gordonii mutant BYW1.