Fig. 1. Electron micrographs of apoptotic cell death within the zebrafish embryo at shield stage. (A) A vertical view of a zebrafish embryo at shield (6 hpf) stage, revealing an apparently normal developmental pattern that includes the enveloping layer (EVL; black arrow), an apoptotic cell (short arrow) and a phagocytotic cell (long arrow). These features are located at the deep cell multilayer, 4-5 cell layers from the blastoderm margin (BM). (B) A horizontal view of a zebrafish embryo at the shield (6hpf) stage. The apoptotic cell corpses include a highly condensed chromatin cell (short arrow). A substantial quantity of enclosed membrane material derived from multi-micronuclei (long arrow) suggests that the apoptotic cell is entering the late apoptotic cell stage. (C) An apoptotic cell engulfed by neighboring cells, revealing a normal nucleus (N) and a substantial quantity of multi-micronuclei (arrows). Scale bars: 10 µM in A,B; 1 µM in C.