Histologische Untersuchungen �ber die Regeneration von Landplanarien

The history and enduring contributions of planarians to the study of animal regeneration

Having an almost unlimited capacity to regenerate tissues lost to age and injury, planarians have long fascinated naturalists. In the Western hemisphere alone, their documented history spans more than 200 years. Planarians were described in the early 19th century as being 'immortal under the edge of the knife', and initial investigation of these remarkable animals was significantly influenced by studies of regeneration in other organisms and from the flourishing field of experimental embryology in the late 19th and early 20th centuries. This review strives to place the study of planarian regeneration into a broader historical context by focusing on the significance and evolution of knowledge in this field. It also synthesizes our current molecular understanding of the mechanisms of planarian regeneration uncovered since this animal's relatively recent entrance into the molecular-genetic age.

Epidermal cell migration during wound healing in Dugesia lugubris. Observations based on scanning electron microscopy and treatment with cytochalasin

The epidermal cells that migrate over the surface during the wound closure stage of head regeneration in Dugesia lugubris s.l. were examined by scanning electron microscopy. The effect of cytochalasin B on epidermal cell migration was also examined. During the first few hours after decapitation epidermal cells at the edges of the wound showed significant changes of shape related to the process of migration that was accomplished approximately 10 h after wounding. Flattening of the marginal cells was associated with active epidermal spreading throughout the healing period. Suitable support for migrating cells appeared to be a rhabditic network attached to the wound tissue. Epidermal cell migration was inhibited by cytochalasin B. These results demonstrate that the basis for cell movement in planarians is similar to that of many other systems.