Figure 4.

Changes in the Na⁺/H⁺ activity of wild-type and desA⁻/desD⁻ cells during incubation in the presence of 1.0 M NaCl in darkness and in light at 50 μE⋅m⁻²⋅s⁻¹. At designated times, 20 μl of the suspension was withdrawn and diluted 100-fold with Na⁺-free medium that contained 5 μM acridine orange. The Na⁺/H⁺ antiport activity was determined as described in the text. ○, Wild-type cells in light; ▵, wild-type cells in darkness; ●, desA⁻/desD⁻ cells in light; and ▴, desA⁻/desD⁻ cells in darkness. Each point represents the average of results from four independent experiments.