FIGURE 3.

Effects of Mg²⁺ and K⁺ on the physiology of Zymomonas mobilis TISTR 548 at critical high temperatures. Under all conditions, the final concentrations of the added MgCl₂ and KCl were 5 and 30 mM, respectively. (A–E) Morphology of cells grown in YPD medium at 30°C (A) or 39°C (B) with MgCl₂ (C), KCl (D), or both (E) for 7 h under a static condition. Photographs were taken at a magnification of ×400. Bars indicate 10 μm. (F) A box plot of cell length from 100 cells measured in these conditions. The median cell length under each condition is shown as a number. (G) Ethanol concentration was measured in culture at 39°C for 12 h in YPD medium under a static condition. (H) The intracellular ROS level was measured in culture at 39°C for 12 h. Index was calculated as the ratio of the fluorescence intensity and protein concentration to the values of the control. Values and error bars represent means and standard deviations, respectively, for triplicate experiments.