FIG 7.

The ΔdksA mutant strain constitutively overproduces (p)ppGpp. (A) Representative TLC image for analysis of radiolabeled nucleotides from 297 wild-type (WT), ΔdksA mutant, and ΔdksA pDksA mutant strains cultured in BSK II medium with [³²P]orthophosphate. Spirochetes were grown to 1 × 10⁸ spirochetes ml⁻¹ (0 hours) and starved in RPMI 1640 medium (6 hours RPMI) before nucleotides were isolated and resolved by TLC. (B) Quantification of (p)ppGpp levels by densitometry. The values represent mean (p)ppGpp levels normalized to (p)ppGpp plus GTP from three independent experiments. Error bars represent standard deviation. Asterisks indicate P values of <0.05, as determined using one-way ANOVA with Tukey’s post hoc test.