Figure 1

High osmolarity triggers a variety of responses in Dictyostelium cells. (A) Redistribution of the F-actin cytoskeleton in response to hyperosmotic shock. After starvation for 4 hours, untreated cells and cells treated for 5 min with 50, 100, 200 and 400 mM sorbitol were fixed with ice cold methanol, and then stained with a monoclonal antibody specific for actin, followed by the incubation with anti-mouse IgG antibody conjugated with Cy5. Size bar is 10 μm. (B) Decrease of cell volume in response to hyperosmotic condition. Dictyostelium cells were treated with increasing sorbitol concentrations for 5 minutes. Cell volume was measured with a microcapillary. Values represent the mean of three independent experiments ± standard deviation (SD). (C) Cell survival in response to hyperosmotic shock. Cell survival was measured by plating out treated or untreated cells on Klebsiella aerogenes lawns and counting the plaques after 2 days of incubation at 21°C. Values represent the mean of three independent experiments ± SD.