Table 2

Diameter of zone of inhibition of E. coli cells expressing H. pylori native or variant AhpC proteinsa

PlasmidDiam of zone of inhibition (mm)
No IPTG0.1 mM IPTG
pET21b (vector control)50 ± 452 ± 4
pET-AhpC48 ± 141 ± 2
pET-AhpC.M101I49 ± 153 ± 3
pET-AhpC.M133I51 ± 158 ± 5
pET-AhpC.M101I. M133I49 ± 155 ± 2
  • a E. coli BL21 RIL cells transformed with the appropriate plasmid were mixed with top agarose and spread on top of LB plates (ampicillin [Amp], chloramphenicol [Cm]) supplemented with 0.1 mM IPTG when indicated. Sterile paper disks (7.5-mm diameter) with t-BH were placed in the center of each plate, and the diameter of the inhibition zone was recorded after 24 h of growth. Results shown represent means and standard deviations of the results of measurements done on 3 to 5 plates, and the inhibition zone for pET-AhpC with IPTG was statistically significantly smaller than for all the other strains (P < 0.05, Student's t test).