Quantifying Urease Activity in H. pylori

AGS cells were cultured in two 12 well plates and incubated with lactobacilli (MOI = 100) and H. pylori P12-GFP (MOI = 100) for 6h. At the end of incubation, one plate of the cells was washed thrice with PBS and photographed by fluorescence and white light. A Urease detection reagent was prepared by adding concentrated hydrochloric acid into the PBS (pH=7.4) to adjust the solution to pH=6.8. Urea (Solarbio) and phenol red (Solarbio) were weighed and added to reach concentrations of 110mmol/L and 10mg/L, respectively, and then dissolved by vigorously shaking. To the other 12well plates, 1 ml Urease detection reagent was added. After 1-7 hours of reaction, 80μl medium was withdrawn to record the absorbance value at 540nm(Shmuely et al., 2004 (link); Rokka et al., 2008 (link); Tharmalingam et al., 2014 (link); Yang et al., 2020 (link)).