Fig. 11

Double-nucleoside labeling experiments with postlarval and juvenile instars of T. orbiculare. BrdU (green) and EdU (red) labeling (4 h Brdu, 64 h sea water, 4 h EdU, sacrifice) with nuclear counterstain (blue). All images show maximum projections in ventral view, apart from those positioned to the right of stippled vertical lines, which are lateral views of the hemiganglia of one body half. For a clearer depiction of the proliferation marker patterns, the nuclear counterstain and BrdU signal have been successively removed from left to right. Stippled ovals highlight the position of the internal VOs in one body half. Curved stippled lines highlight the characteristic sickle-like arrangement of the BrdU-positive cells. Black arrows point at exclusively EdU-labeled nuclei in advanced VO-stages. White arrowheads indicate exclusively EdU-labeled, flattened nuclei of peripheral glial cells. White arrows mark selected EdU-positive nuclei of cells just outside the VOs, potentially indicative of further divisions after cells have started to migrate. a–a”: Wlg 2–4 of the penultimate postlarval instar. b–b”: Wlg 2–4 of the last postlarval instar. c–c”: Wlg 2–4 of the first juvenile instar. Abbreviations: wlg – walking leg ganglion