Figure 3.

Effect of 1⁴⁺ concentration on the growth and viability of E. coli strain EC958 in glucose defined minimal medium. (A) Cultures were grown to early exponential phase at 37 °C and 150 rpm shaking in 250 mL flasks with defined minimal medium containing glucose as the sole carbon source. Upon reaching an OD₆₀₀ ∼ 0.4 differing concentrations of 1⁴⁺ (0–5 μM) were added to the cultures and growth was monitored at regular intervals. N ≥ 3 ± SEM. (B) Samples of the cultures described in (A) were removed and viable counts performed to determine the bactericidal effect of 1⁴⁺ at differing concentrations between 0–5 μM. N ≥ 3 ± SEM. Statistical significance (**) was determined with two-way ANOVA and Tukey’s multiple comparisons (p < 0.05). (C) Localization of 1⁴⁺ in E. coli EC958 cells was visualized through structured illumination microscopy at 0, 20, 60, and 120 min. Cells were imaged using the emission of 1⁴⁺ on excitation at 450 nm using A568 filter. After treatment with 0.8 μM 1⁴⁺, cells were washed with nitric acid before fixing with paraformaldehyde (4%). Images were taken using a 1516× oil objective and SlowFade Gold Antifade Mountant.