Fig. 2

Measurement of total cellular Na⁺ concentration. Wild-type (WT), ΔprkA (prkA deletion mutant), and CΔprkA (complement of ΔprkA) bacterial cells were grown to OD₆₀₀ ≈ 0.8 in TY broth medium and then adjusted to OD₆₀₀ ≈ 0.2. The diluted inocula were plated on TY agar plates with and without 0.4 M NaCl and inoculated at 28 °C for 5 days. Total cellular Na⁺ concentrations were measured using an atomic absorption spectrophotometer. The results are shown as the means of three biological replicates and the error bars indicate standard deviations. The significance of differences is shown at the P < 0.05 level (t-test). Different lowercase letters mean significant difference between two columns