Figure 3

Apoptotic cells during degeneration of segmental thickenings. Confocal laser-scanning micrographs from a late stage VI embryo of Euperipatoides rowelli  (Peripatopsidae). Same embryo as in Figure 2H. Anterior is up in all images. (A) Overview of the ventral body surface labelled with the DNA marker Bisbenzimide. Note the persisting, paired cell strands that connect the segmental thickenings along the body. (B) Same embryo labelled with a cell death detection kit (Terminal deoxynucleotidyl transferase dUTP nick end labelling – TUNEL). Doted circles indicate areas in the interpedal regions, where numerous apoptoses are seen. (C) Detail of the same embryo showing a merged image of DNA and TUNEL labelling. Dotted circles indicate areas with numerous apoptotic cells. Asterisks indicate the paired segmental thickenings (=anlagen of the ventral and preventral organs). Abbreviations: cs, cell strand; dp; developing dermal papilla; lg, presumptive leg; st, segmental thickening. Scale bars: 200 μm (A, B), and 100 μm (C).