The origin and continuous replacement of epidermal cells in the planarian Polycelis tenuis (lijima)
1965; The Company of Biologists; Volume: 13; Issue: 1 Linguagem: Inglês
10.1242/dev.13.1.129
ISSN1477-9129
Autores Tópico(s)Protist diversity and phylogeny
ResumoABSTRACT RAY LANKESTER (1873) coined the term ‘Triploblastic’ and supposed that the gut, parenchyma and epidermis of Turbellaria corresponded to the germ layers of contemporary dogma. This idea is still current, though neither the origin, nor the maintenance of the epidermis of planarians has been investigated in detail. Most embryological studies have been restricted to early development, but Bardeen (1902) worked on embryos of a wide range of ages and claimed that their epidermal cells divide amitotically. Both Mattiesen (1904) and Fulinsky (1916), however, denied that cell division occurs there, and since this has been confirmed for the epidermis of the adult (Skaer, 1961), the cells must be recruited from elsewhere. I suggested that the entire epidermis might be continuously renewed by migration of cells from the parenchyma to the periphery.
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