Regeneration in Planaria

Phillip A Newmark, Carnegie Institution of Washington, Baltimore, Maryland, USA
Alejandro Sánchez Alvarado, Carnegie Institution of Washington, Baltimore, Maryland, USA

Published online: April 2001

DOI: 10.1038/npg.els.0001097

Planarians possess remarkable regenerative abilities enabling them to replace parts of the body removed by amputation or naturally occurring fission. The regenerative process is mediated by the formation and eventual differentiation of a specialized structure known as the regeneration blastema.

Keywords: regeneration; platyhelminthes; blastema; neoblasts; planarian

Figure 1. The process of head regeneration in Dugesia dorotocephala. (a) Schematic representation of blastemal components. The round cells correspond to the zone of neoblast proliferation in the vicinity of the wound (e, epithelium; m, neoblast-derived mesenchymal cells; n, neoblast; ex, extracellular matrix). (b) The same animal photographed every 24 hours after amputation. The numbers refer to days after amputation. Notice the marked cellular proliferation as evidenced by the growth of the blastema between days 2 and 3.
Figure 2. The planarian gastrovascular and nervous systems. (a) Visualization of the three gut branches (1, 2, 3) by feeding the animals fluorescent latex beads. Notice the intricate web of fasciculations of each of the secondary branches. This allows the transport of both oxygen and nutrients to all parts of the body. (b) The planarian brain consisting of two cerebral ganglia (+) seen at a ×40 magnification. (c) The two nerve cords, each originating in one of the two cerebral ganglia are seen here at the trunk level (*) running parallel to the pharynx (×20 magnification). (d) The nerve cords at the tail tip of the planarian displaying commissural neurons (arrow) which connect the cords along the entire AP axis of the animal (×40 magnification). The nervous system in panels b, c and d was visualized by labelling neurons with an anti-FMRF amide primary antibody (a neuropeptide) detected with a secondary fluorescent-conjugated antibody.We acknowledge the expert confocal microscopy assistance provided by Susanna Castel.
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 References
    Baguñà J et al. (1989) Regeneration and pattern formation in planarians. III. Evidence that neoblasts are totipotent stem cells and the source of blastema cells. Development 107: 77–86.
    book Baguñà J et al. (1990) "Growth, degrowth and regeneration as developmental phenomena in adult freshwater planarians". In: Marthy H-J (ed.) Experimental Embryology in Aquatic Plants and Animals, pp. 129–162. New York: Plenum Press.
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    Bueno D et al. (1997) Cell-, tissue-, and position-specific monoclonal antibodies against the planarian Dugesia (Girardia) tigrina. Histochemistry and Cell Biology 107:139–149.
    book Dinsmore CE (ed.) (1991) A History of Regeneration Research: Milestones in the Evolution of a Science. Cambridge: Cambridge University Press.
    Gremigni V et al. (1980) On the role of germ cells in planarian regeneration. I. A karyological investigation. II. Cytophotometric analysis of the nuclear Feulgen-DNA content in cells of regenerated somatic tissues. Journal of Embryology and Experimental Morphology 55: 53–76.
    book Hyman L (1951) The Invertebrates: Platyhelminthes and Rhynchocoela, vol. II. New York: McGraw-Hill.
    Saló E and Baguñà J (1985) Cell movement in intact and regenerating planarians. Quantitation using chromosomal, nuclear and cytoplasmic markers. Journal of Embryology and Experimental Morphology 89: 57–70.
 Further Reading
    book Baguñà J and Boyer BC (1990) "Descriptive and experimental embryology of the Turbellaria: present knowledge, open questions and future trends". In: Marthy H-J (ed.) Experimental Embryology in Aquatic Plants and Animals, pp. 95–128. New York: Plenum Press.
    book Ellis Jr. CH and Fausto-Sterling A (1997) "Platyhelminthes, the flatworms". In: Gilbert SF and Raunio AM (eds) Embryology: Constructing the Organism, pp. 115–130. Sunderland, MA: Sinauer Associates.
    book Lender T (1962) "Factors in morphogenesis of regenerating fresh-water planaria". In: Abercrombie M and Brachet J (eds) Advances in Morphogenesis, vol. 2, pp. 305–331. New York: Academic Press.
    book Mitman G and Fausto-Sterling A (1992) "Whatever happened to Planaria? C.M. Child and the physiology of inheritance". In: Clarke AE and Fujimura JH (eds) The Right Tools for the Job: At Work in Twentieth-Century Life Sciences, pp. 172–197. Princeton, NJ: Princeton University Press.
    book Morgan TH (1901) Regeneration. New York: Macmillan.
    book Wolff E (1962) "Recent researches on the regeneration of planaria". In: Rudnick D (ed.) Regeneration. 20th Growth Symposium, pp. 53–84. New York: The Ronald Press.

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Regeneration: Invertebrates
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Article Title: Regeneration in Planaria
 
How to Cite close
Newmark, Phillip A, and Alvarado, Alejandro Sánchez(Apr 2001) Regeneration in Planaria. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1038/npg.els.0001097]