(a) Survival of stationary-phase L. rhamnosus GG in simulated gastric juice, pH 2.0, containing glucose (▪), glucose and DCCD (□), no glucose (♦), or no glucose and DCCD (▴). (b) Survival of stationary-phase parent (w/t) and neomycin-resistant L. rhamnosus GG (m5, m8, m14, and m18) cultures in simulated gastric juice containing glucose, pH 2.0, following 45 min of exposure (bars) and ATPase activity of permeabilized cells (▵). The data are the means of triplicate experiments, and the error bars indicate standard deviations.