Fig. 2

Cell shape analysis of early P. tepidariorum embryos via WGA and phalloidin staining. a An early stage 1 embryo has been injected with FITC dextran. Several cells have taken up the injected dye and the perinuclear cytoplasm has been labelled. To label the cell membranes, the same embryo has been re-injected with FITC-WGA at late stage 2 (a’). b Living embryo at late stage 2 stained with FITC-WGA. Arrowhead points towards WGA staining within the vitelline membrane. Single optical slice through a late stage 2 embryo stained for FITC WGA and DAPI (c) or acetylated tubulin and DAPI (d). As excessive DAPI has not been washed away, the yolk granules are stained, additionally (d). Asterisk in c and d indicate big yolk globules that are inside of the cells. e and f Confocal scans (maximum intensity projections) of the embryonic (e) and extra-embryonic (f) cells of living stage 3 embryos that have been injected with FITC WGA. The arrowhead marks the primary thickening in e. g Single optical slice through the germ-disc cells of a stage 4 embryo stained for FITC WGA and DAPI. h-k Embryos stained with phalloidin to mark actin and DAPI to mark the nucleus of each cell. View on top of the germ-disc is shown in i. View on the extra-embryonic region of a stage 4 embryo is shown in j. k Confocal scan (maximum intensity projection) of a stage 4 embryo that has been stained with phalloidin and DAPI. Two nuclei are present in one cell (arrowheads). k’ Single optical slice through the boxed region shown in k. l Schematic interpretation of the cells shown in c, g and k'. Cell membranes, red; nuclei, grey; perinuclear cytoplasm, black; yolk, yellow. Dotted lines indicate the cell outlines in d, j and k’. Orthogonal views are boxed in green and red in c, d, g and k’. Scale bar is 50 μm in all panels