Figure 2

Time course of posterior regeneration in C. teleta from 4 hours to 18 days post-amputation. Adults were amputated at the 12^th segment. Panels shown are posterior ends of amputated adults. All animals are oriented in a ventral view with anterior to the left. Black and white dotted lines indicate cut site in all panels. Dark shapes in E, F', I', J and K are within the lumen of the gut. Images F and I are Z-stack projections of confocal micrographs of the posterior end of a regenerate labeled with anti-acyetylated tubulin. Abbreviation: pyg, pygidium. (A) Schematic of an adult worm indicating the cut site at the 12^th segment. (B) Adult worm four hours post-amputation. (C) one day post-amputation. (D) three days post-amputation. (E) five days post-amputation. (F) Confocal micrograph of a worm five days post-amputation showing longitudinal axons extending into the regenerating tissue (white arrow). (F') Corresponding DIC image of the same worm shown in F. (G) seven days post-amputation. (H) 10 days post-amputation. (I) Confocal micrograph of a worm 10 days post-amputation showing longitudinal axons (white arrow) and circular nerves (white arrowheads) in the regenerating tissue. (I') Corresponding DIC image of the same adult worm in I; note the lack of external segmentation (black arrow). (J) 14 days post-amputation worm with a distinct pygidium. (K) Adult 18 days post-amputation with numerous differentiated segments in the regenerate. Black arrowheads point to chaetae in two sets of adjacent segments. Scale bar, 50 μm for all panels.