Regeneration of the digestive system in the crinoid Himerometra robustipinna occurs by transdifferentiation of neurosecretory-like cells
Fig 5
Microscopic organization of the cellular layer covering the surface of the calyx at 6–12 h post-autotomy in H. robustipinna.
(A) Transverse (oral-aboral) semithin section of the oral part of the calyx at 6 h post-autotomy. (B) Cellular layer on the surface of the calyx at 6 h post-autotomy. (C) Juxtaligamental cells covering the torn septa of the aboral coelom at 6 h post-autotomy. (D) Transforming type 2 granules at 12 h post-autotomy. (E) Juxtaligamental cell with type 2 granules undergoing destruction at 12 h post-autotomy. (F) Golgi apparatus in the cytoplasm of juxtaligamental cell at 12 h post-autotomy. (G) Large vacuoles in the cytoplasm of juxtaligamental cell at 12 h post-autotomy. ac, amoebocyte; ce, coelomic epithelial cell; ci, cilium; cl, cellular layer; cx, calyx; g1, type 1 granule; g2, type 2 granule; ga, Golgi apparatus; jlc, juxtaligamental cell; nc, process of nerve cell; rer, rough endoplasmic reticulum; v, vacuole. Scale bars: (A) 50 μm, (B) 4 μm, (C, E, F) 2 μm, (D, G) 0.5 μm.