Fig. 12

Distribution of BrdU- and EdU-positive cells in walking leg ganglion 3 of T. orbiculare. BrdU (green) and EdU (red) labeling (4 h Brdu, 64 h sea water, 4 h EdU, sacrifice) with acetylated tubulin (white) and nuclear counterstain (blue). All images show horizontal optical sections through walking leg ganglion 3 of the last postlarval instar, proceeding from apical to basal. For clearer depiction of the proliferation marker patterns, tubulin labeling plus nuclear counterstain and the BrdU signal have been successively removed from left to right. The wide stippled outlines trace the extension of the ganglionic soma cortex. Stippled ovals highlight the position of the internal VOs in one body half (a–c). Black arrows (d) point at BrdU and EdU co-labeled nuclei in the cell band emanating dorsally from the VO and running posterior to the neuropil, suggestive of further divisions during cell migration. White arrowheads (d) mark neurite bundles of the ventral longitudinal tract which becomes recognizable in these stages. White arrows (b–d) point at potential pycnotic bodies indicative of cell death occurring in addition to cell proliferation in the VOs and the migratory cell bands. Note the heterogeneous nucleus sizes in the internal VOs (a–c) as well as similar nucleus size and morphology of BrdU-positive cells and surrounding somata in areas outside the VOs and deeper in the cortex (c–e)