Figure 2.

Lower motility of bacteria caused by Ag⁺ ions. (A) The dependence of the mean displacements ($\overline{{\mathsf{\Delta }}^{0}r}$) of the first 12 frames of all trajectories of bacteria on incubation/treatment time in the absence (0 µM) and presence of Ag⁺ ions (40 µM). (B) The dependence of the mean bacterial velocity on incubation/treatment time in the absence (0 µM) and presence of Ag⁺ ions (40 µM). (C) Distributions of bacterial velocities in the presence of Ag⁺ ions at 40 µM for 0, 1, 2, and 4 h. Inset: the corresponding result for untreated bacteria (0 µM). The axes of the inset are the same as the main figure. (D) Cell-viability assay based on propidium iodide (PI) staining for untreated (0 h, left column) and treated (2 h, right column) bacteria. Top: inverted phase-contrast (IPC) images; middle: fluorescence images due to PI staining; bottom: merged IPC/PI images. Scale bar = 16 µm. (E) Log–log plot of mean-square displacements (MSDs) vs. lag time ($\tau$) for trajectories of treated bacteria by Ag⁺ ions at 40 µM for 0, 1, 2, and 4 h. Inset: the corresponding result for untreated bacteria (0 µM). (F) Dependencies of the generalized diffusion coefficient D and the anomalous scaling exponent $\alpha$ (inset) on the incubation/treatment time T_tr.