Fig. 5

Cell proliferation in the VNC of postlarval and juvenile Ph. femoratum instars. Labeling of acetylated tubulin (white) and EdU (red) with nuclear counterstain (blue) after 4 h EdU exposure. Maximum projections (a, c) and optical sections (b, b’, d, d’) of wholemount CNSs, anterior to the top. Stippled ovals highlight the internal VOs of one body half. Stars indicate the central cavity around which tubulin-rich cell processes converge. White arrows indicate broad tubulin-rich cell bands (b’) and more condensed fibrous strands (d’) extending dorsally from the VOs towards the neuropil. Asterisks mark transient posterior ganglion anlagen. a: CNS of the last postlarval instar, ventral view, EdU labeling shown separately on the right. Note the gradual antero-posterior increase of cell proliferation. b & b’: Wlg3–4, horizontal and sagittal sections. Black arrows mark larger nuclei in the VOs of wlg4. Note also wider cavities of the VOs in wlg4. c: CNS of the first juvenile instar, ventral view, EdU labeling shown separately on the right. Arrowheads mark single EdU-positive cells in the periphery of the ganglia. d & d’: Wlg3–4, horizontal and sagittal sections. Only few large VO nuclei remain (black arrow), VO nuclei being generally smaller than the neuronal nuclei in the soma cortex. Arrowheads mark the ventral longitudinal tract in wlg3. Abbreviations: br – brain, ovn – ovigeral neuromere, pan – palpal neuromere, seg – subesophageal ganglion, wlg – walking leg ganglion, wln – walking leg neuromere