A, Time course of changes in cellular carbon and nitrogen. Arrows indicate when the nitrogen starvation started and when nitrogen was resupplied to the culture. B, Cellular dissolved protein content at the 10-, 16-, 31-, and 32-d sampling points. Cultures from the four points were used as studies of proteomics. Days 16 and 31 (nitrate depletion) were compared with day 10 (nitrate repletion), while day 32 was compared with day 31. Asterisks indicate significant differences determined by an independent Student’s t test (*P < 0.05, **P < 0.001). The experiment was repeated two times, and the values are means ± sd (n = 6). [See online article for color version of this figure.]