Antagonism of Bacteria from Dog Dental Plaque against Human Cariogenic Bacteria

Figure 1

Sequence of spot-on-the-lawn surface to establish antagonistic activity of one strain of bacteria against a target strain and to confirm the protein nature of this inhibition; (a) 2 μL of test strain is inoculated on the surface of Petri dishes containing agar; (b) formation of the colonies of test strain on the agar surface; (c) addition of a semisolid agar overlayer with the target bacteria; (d) inhibition halo after the incubation of target strain, confirming antagonistic activity; (e) four holes adjacent to the colonies made to inoculation of different proteinases; (f) interference of bovine pancreatic trypsin on inhibition halo of test strain against target strain, confirming the protein nature of antagonistic activity.