Fig. 5. Transfer of the fluorescent membrane dye, PKH67 from labeled small yolk granules (SYGs) to larger YGs after calcium treatment. (A,C,E) DIC images; (B,D,F) corresponding fluorescence images. (A,B) SYGs. Scale bar, 50 µm. (C,D) Dye transfer from SYGs to large ones. Note the appearance of large stained YGs as the result of incubation with Ca²⁺. Scale bar, 25 µm. (E,F) Incubation of labeled SYGs with day 0 YGs in the presence of 10 mmol l^-1 EGTA (calcium-free medium). Note that dye transfer did not occur. Scale bar, 25 µm.