FIG. 3.

Analysis of mutacin IV (nlmA) production in the hdrM background. The production of mutacin IV was tested by the deferred antagonism assay as described in Materials and Methods. The development of a growth inhibition halo is indicative of the presence of mutacin IV inhibiting the sensitive strain S. sanguinis NY101. S. mutans strains are identified as follows: WT (wild-type UA140), ΔE (comE mutant), ΔM (hdrM mutant), ΔM/E (hdrM comE double mutant), ΔIV (nlmA mutant), and ΔM/E/IV (hdrM comE nlmA triple mutant). This experiment was performed three times with similar results.