Fig. 5.

K⁺ indirectly regulates the expression of kdp operon. a In vitro transcription at increasing K⁺ concentrations ranging from 150 to 300 mM. b Intracellular cyclic diadenylate monophosphate (c-di-AMP) levels of BMB171 cells grown in TSB and TSB-Na. The c-di-AMP concentrations were determined by LC-MS/MS (liquid chromatography with tandem mass spectrometry). Data are expressed as box-and-whisker plots, where the central lines denote medians, edges represent upper and lower quartiles, and whiskers show the minimum and maximum values. Data were subjected to one-way analysis of variance (ANOVA) using the Bonferroni test, n = 3; p values are shown above each panel. Data underlying the plots in b are available in Supplementary Data 5