Figure 4.

Schematic illustration of the leukotoxin promoter region. Extracted DNA from saliva of individuals positive for A. actinomycetemcomitans strains of serotype b was amplified by PCR using leukotoxin promoter-specific primers. The PCR products were visualized on an agarose gel, and one DNA band corresponding in size to that of the JP2 genotype was extracted from the gel and sent for DNA sequencing. The obtained sequence (highlighted in black) revealed the absence of the specific 530 base pair (bp) fragment (highlighted in dark gray), which is a specific characteristic of the JP2 genotype of A. actinomycetemcomitans.