Figure 5

Semithin sections and whole mounts of 24 hour tail plate blastemas. Schemes are indicating the orientation of the animal in the respective subpanels. (A) Blastema is still located ventrally. Note the mitosis at the anterior end of the blastema (arrowhead). The newly built epidermal layer is characterized through smaller, often less ciliated cells (area above scale bar). A cell migrating to the epidermal layer is shown by the arrow. (B) Blastema is already located caudally. Arrowhead denotes a dorsoventral muscle fiber. (A, B) stained after Heidenhain, (C, E, G) with methylene blue. (C, D, E) BrdU pulse (brown) was applied just before fixation. All three subpanels from the same animal. (C) Complete section, anterior is left. Note the accumulation of labeled neoblasts in the caudal blastema (right). (D) Whole mount and (E) section of the blastema, with accumulation of neoblasts. fa female antrum. (F, G) BrdU pulse chase experiment. Both subpanels are from the same animal. Note the accumulation of labeled cells in the blastema, but the absence of labeled cells in the epidermis. Dotted lines indicate blastema extension. All scale bars are 20 μm, except 50 μm in (C). (D, F) and (E, G) in the same scale.