Fig. 4

Indirect immunofluorescence microscopy showing successive stages of embryogenesis in G. pectorale. Each column shows a differential interference contrast (DIC) image (top row), a fluorescence image labeled with anti-SAS-6 antibody (green) and DAPI (blue) (second row), a merged DIC and fluorescence image of anti-SAS-6 antibody and DAPI (third row), and a fluorescence image labeled with anti-tubulin α antibody (magenta) of the same embryo. Positions of nuclei (letter n), chloroplasts (letter c), and basal bodies labeled with the anti-SAS-6 antibody (arrowheads) are shown. Scale bars: 5 μm. a Early 8-celled stage. b Late 8-celled stage. c Early 16-celled stage, just after the successive cell divisions. Basal bodies of daughter protoplasts are positioned in the center of the concave surface of the cell layer during successive cell divisions (a–c). d Mid 16-celled stage during partial inversion showing emitted flagella (arrow). The basal bodies of peripheral daughter protoplasts (arrowheads) have become separated from each other and are located slightly outside of the position of the nuclei. e After hatching. The basal bodies of peripheral cells (arrowheads) point toward the outside of the daughter colony