Fig. 3. The cER network in cortices isolated from eggs and 8-cell-stage embryos. (A-D) ER networks from cortices isolated from live unfertilized eggs labelled with the lipophilic dye DiIC16(3) and viewed with fluorescence microscopy (A,B), or prepared for electron microscopy using the fast-freeze deep-etch method (C,D), revealing ribosomal particles (arrows in D) mixed with smaller or odd-shaped particles (arrowheads). (E-G) High-magnification confocal sections of the DiOC6(3)-labelled CAB region in live cortices isolated from 8-cell embryos. (E) Confocal section close to the plasma membrane. The ER network in the CAB (arrowhead) is contiguous with the surrounding cER network. Vesicles are present in the CAB. (F) Three, evenly-spaced confocal sections (bottom, middle and top) through a CAB isolated with the cortex. The third image is an enlarged view of the ER network. (G) The ER network vesiculates (arrowheads) when a live labelled cortex is exposed to hypotonic solution.