Proteomic profiling of N. oceanica IMET1 in response to the removal and addition of nitrate. Soluble proteins were isolated from N. oceanica IMET1 and resolved in a nonlinear pH 4 to 7 gradient and on 12.5% SDS-PAGE gels. D10, D16, and D31 are two-dimensional gels for the samples taken on days 10, 16, and 31, respectively, during nitrate depletion, and 24-Hr is a two-dimensional gel for the sample taken at 24 h after nitrate was resupplied. During nitrate depletion, gels from day 10 were used as a control, and other time points (days 16 and 31) were compared with them. For nitrate recovery, 24-h recovery was compared with day 31. Red circles on the gels show the identified differentially expressed spots. Numbers 1 to 33 on the D10, D16, and D31 gels correspond to spots numbered in Table II, and numbers S1 to S14 corresponds to spots numbered in Table III. [See online article for color version of this figure.]