Table 1.
Calcium (Ca) removed from the treatment solution and bound to bacterial pellet (mean ± sd; n = 4) after 60-min equilibrium with 1 or 10 mM Ca treatments.
Fig 1.
Kinetics of calcium binding to S. mutans.
Ca concentration in the bacterial pellet as a function of time and of Ca concentration in the treatment solution (mean ± SD, n = 3).
Fig 2.
Calcium binding at equilibrium.
Calcium concentration (μmol/g, mean ± sd, n = 3) in the bacterial pellet after 60 min of equilibrium of bacteria with PIPES buffer pH 7.0, containing 0 mM, 1 mM, 10 mM Ca in treatment solution or pretreated with 1 and re-equilibrated with 10 mM Ca.
Table 2.
Calcium binding maximum capacity (Cabmax) and equilibrium constant (Kd) calculated from the best-fit values of the binding curve kinetics as a function of Ca concentration in treatment solution (mean ± sd, n = 3).
Fig 3.
Kinetics of calcium release from S. mutans.
Calcium concentration remaining in the bacterial pellets pretreated with 1 or 10 mM Ca as a function of time of exposure to a calcium-free (0 mM Ca) or a 1 mM Ca solution (mean ± SD, n = 3).
Table 3.
Calcium concentration in the bacterial pellet (Cab0) after pretreatment for 10 min with solutions containing 1 or 10 mM Ca, estimated binding at infinity (Cab∞) after equilibrium with calcium-free or 1 mM Ca solution and and half-life values calculated from kinetics release curve, for the different conditions tested (mean ± sd, n = 3).
Fig 4.
Calcium release from S. mutans at decreasing pHs.
C concentration (mM, mean ± sd, n = 3), in treatment solution initially and after 10 min of equilibrium of bacteria with PIPES buffer pH 7.0, acetate buffer pH 5.0 and HCl pH 1.86 at proportion of 30% the treatment solution per bacterial weight (simulating the liquid-solid proportion in dental biofilms). Pretreatment conditions were 1 or 10 mM Ca. *Initial and final values differ statistically (paired t-test; p<0.05).