Fig. 7.

Cellular uptake of formycin A (a) (b) and formycin B (c) by the H. pylori 26695 strain after 8 h of incubation, quantified by various methods of detection, LC–MS, UV absorbance or inhibition by a target enzyme, purine nucleoside phosphorylase. In the case of the absorbance method, shifting observation to the longer wavelength allowed monitoring experiments with lower inhibitor concentrations (here shown for 35 µM FA). Green bars show inhibitor concentration observed at the start of the incubation. Black and blue bars show data (extracellular inhibitor concentration) obtained for incubation at 37 °C and 4 °C, respectively. Open bars indicate inhibitor incubated in the F12 medium, while filled bars indicate inhibitor incubated in F12 medium containing H. pylori cells. Results are mean ± SEM, n = 3, ****p < 0.0001; ***p < 0.001; **p < 0.01, *p < 0.05