Fig 7.

Changes in cell volume of Synechocystis wild-type and ΔaqpZ cells in response to hyperosmotic shock. (A) Light microscopy photographs of Synechocystis WT and ΔaqpZ cells before and 5 min after the start of osmotic stress by addition of 0.5 M sorbitol or 0.5 M NaCl. (B) Time course of morphological changes of single Synechocystis WT and ΔaqpZ cells after the addition of sorbitol. (C and D) Determination of changes in cell volume by EPR. Cells were treated with 0.5 M sorbitol (C) or 0.5 M NaCl (D) at time zero. At designated times, samples were withdrawn from each cell suspension and the cell volume was determined by EPR. Each point represents the average ± SE from four independent experiments.