FIG 3 .

Multiplication and genome replication of T. pallidum Nichols in Sf1Ep cocultures and axenic cultures. Fold increases are shown in parentheses. The axenic cultures were initiated in parallel with the Sf1Ep cocultures in experiment 1 (Table 2) (Fig. 1), using the same frozen stock of T. pallidum. (A) The number of T. pallidum organisms per culture increased only ~2-fold in axenic cultures but increased over 55-fold for cocultures with Sf1Ep cells. Genome equivalent (Equiv.) increases were similar to bacterial cell number increases for the Sf1Ep cocultures but were somewhat higher than the cell number increases for the axenic cultures. (B) Numbers of genome Equiv. per cell remained stable for the exponentially growing cocultures but increased for the axenic cultures. T. pallidum per-culture and genome equivalent values represent means ± SE of results from triplicate cultures.