Fig. 4.

dNTP pool changes in response to inhibitor treatment. P. aeruginosa cultures with an optical density of 0.35 were treated with inhibitors associated with increased RNR expression [streptonigrin (SN), light gray bars; toluidine blue (TB), dark gray bars] or DMSO as a control (open bars). Cultivation was continued for 30 min after addition of inhibitor, after which cells were harvested and dNTPs were extracted and quantified by HPLC. Given concentrations refer to the total amount extracted divided by the culture volume. Both streptonigrin and toluidine blue significantly decreased the total dNTP pool compared with DMSO-treated controls as well as the four individual dNTP pools. The observed differences between individual dNTP levels (i.e., dCTP vs. dGTP vs. dTTP vs. dATP) were not statistically significant, however.