Skip to main content
Log in

Cytological studies on the planarian neoblast

  • Published:
Zeitschrift für Zellforschung und Mikroskopische Anatomie Aims and scope Submit manuscript


The paper is a study of the cytology of the regeneration cells (neoblasts) in Planaria vitta.

The morphology of the living cells has first been examined to provide a reference for an investigation of the fixed neoblasts as studied by ordinary cytological, cytochemical and electron microscopical technics.

A rather selective staining method has been devised based on the strong basophilic properties of the scanty cytoplasm. The morphology of the fixed neoblasts and their distribution in the intact animal have been described, using this method.

The marked cytoplasmic basophilia was found to be exclusively due to ribonucleic acid, and not to desoxyribonucleic acid or acid mucopolysaccharides.

The cytoplasm contains moderate to considerable amounts of basic proteins. Tyrosine, cysteine/cystin, arginine, lysine and perhaps histidine were present, while tryptophan could not be demonstrated.

No enzymes could be demonstrated apart perhaps from cytochrome oxidase.

The mitochondria are small and inconspicuous and more or less evenly distributed throughout the cytoplasm. A Golgi apparatus could not be demonstrated.

The electron microscopic picture is very characteristic, because of the high electron density of the cytoplasm. This density is the result of the presence of a great number of ribonucleoprotein granules. Most of the granules are free and only a minor part bound to the membranes of the endoplasmatic reticulum. The interesting features of the cell membrane are discussed in relation to the structure of the parenchyma.

The cytochemical properties of the neoblast (RNA and sulfhydryl-groupcontaining protein) and the fine structure as revealed in the electron microscope characterize the neoblast as a morphogenetically active cell.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Similar content being viewed by others


  • Brachet, J.: Chemical embryology. New York: Interscience Publ. 1950.

    Google Scholar 

  • Brächet, J.: Biochemical cytology. New York: Academic Press 1957.

    Google Scholar 

  • - Bronn's Klassen und Ordnungen des Tier-Reichs, 4. Ic. II. Leipzig: C. F. Winter 1917.

  • Brøndsted, H. V.: Planarian regeneration. Biol. Rev. 30, 65–126 (1955).

    Google Scholar 

  • Brøndsted, A., and H. V. Brøndsted: Distribution of neoblasts throughout the anterior-posterior body axis in Euplanaria torva and Dendrocöleum lacteum. (In prep.)

  • Brøndsted, A., and H. V. Brøndsted: Distribution of neoblasts in the asexual reproducing Planaria vitta. (In prep.)

  • Cain, A. J.: An easily controlled method for staining mitochondria. Quart. J. micr. Sci. 89, 229–231 (1948).

    Google Scholar 

  • Chalkley, D. T.: The cellular basis of limb regeneration. In: Regeneration in vertebrates. Edit. C. S. Thornton, Chicago: University Chicago Press 1959.

    Google Scholar 

  • Clément-Noël, H.: Les acides pentosenucléiques et la régénération. Ann. Soc. roy. zool. Belg. 75, 25–33 (1944).

    Google Scholar 

  • Deitch, A. D.: Microspectrophotometric study of the binding of the anionic dye, naphthol yellow S, by tissue sections and by purified proteins. Lab. Invest. 4, 324–351 (1955).

    Google Scholar 

  • Dubois, F.: Contribution à l'étude de la migration des cellules de régénération chez les planaires dulcicoles. Bull. biol. 83, 213–283 (1949).

    Google Scholar 

  • Elftman, H.: A direct silver method for the Golgi apparatus. Stain Technol. 27, 47–52 (1952).

    Google Scholar 

  • Gomori, G.: Microscopic histochemistry. Chicago: University Chicago Press 1952.

    Google Scholar 

  • Haguenau, F.: The ergastoplasm: its history, ultrastructure and biochemistry. Int. Rev. Cytol. 7, 425–483 (1958).

    Google Scholar 

  • Holt, S. J.: Indigogenic staining methods for esterases. In: General cytochemical methods, vol. I. New York: Academic Press 1958.

    Google Scholar 

  • Kaufman, N., and R. Hill: Determination of succinic dehydrogenase activity in tissue culture. J. Histochem. Cytochem. 7, 144–146 (1959).

    Google Scholar 

  • Lillie, R. D.: Histopathologic technic and practical histochemistry. New York: Blakiston Son & Co. 1954.

    Google Scholar 

  • Lindh, N. O.: Histological aspects of regeneration in Euplanaria polychroa. Ark. Zool., Ser. 2 11, 89–103 (1957).

    Google Scholar 

  • McLeish, J., L. G. E. Bell, L. F. La Cour and J. Chayen: The quantitative cytochemical estimation of arginine. Exp. Cell Res 12, 120–125 (1957).

    Google Scholar 

  • Mowry, R. W.: Improved procedure for the staining of acidic polysaccharides by Müller's colloidal (hydrous) ferric oxide and its combination with the Feulgen and the periodic acid-Schiff reactions. Lab. Invest. 7, 566–576 (1958).

    Google Scholar 

  • Murray, M. R.: In vitro studies of planarian parenchyma. Arch. cxp. Zellforsch. 11, 656–668 (1931).

    Google Scholar 

  • Palade, G. E.: The endoplasmic reticulum. J. biophys. biochem. Cytol. 2, Suppl., 85–98 (1956).

    Google Scholar 

  • Pearse, A. G. E.: Histochemistry. London: J. and A. Churchill 1953.

    Google Scholar 

  • Pedersen, K. J.: Morphogenetic activities during planarian regeneration as influenced by triethylene melamine. J. Embryol. exp. Morph. 6, 308–334 (1958).

    Google Scholar 

  • Pedersen, K. J.: Some features of the fine structure and histochemistry of planarian subepidermal gland cells. Z. Zellforsch. 50, 121–142 (1959).

    Google Scholar 

  • Prenant, M.: Recherches sur le parenchyme des plathelminthes. Essais d'histologie comparée. Arch. Morph. gén. exp. 5, 1–174 (1922).

    Google Scholar 

  • Robertson, J. D.: The ultrastructure of cell membranes and their derivatives. Biochemical Society Symposia No 16, p. 3–43, 1959.

  • Siekevitz, P.: On the meaning of intracellular structure for metabolic regulation. Ciba Foundation symposium on the regulation of cell metabolism, p. 17–49, 1959.

  • Stéphan-Dubois, F.: Les néoblastes dans la régénération postérieure des Oligochétes microdriles. Bull. biol. 88, 181–247 (1954).

    Google Scholar 

  • Tardent, P.: Über Anordnung und Eigenschaften der interstitiellen Zellen bei Hydra und Tubularia. Rev. suisse Zool. 59, 247–253 (1952).

    Google Scholar 

  • —: Axiale Verteilungs-Gradienten der interstitiellen Zellen bei Hydra und Tubularia und ihre Bedeutung für die Regeneration. Wilhelm Roux' Arch. Entwickl.-Mech. Org. 146, 593–649 (1954).

    Google Scholar 

  • Wagner, B. M., and S. H. Shapiro: Application of alcian blue as a histochemical method. Lab. Invest. 6, 472–477 (1957).

    Google Scholar 

  • Watson, M. L.: Staining of tissue sections for electron microscopy with heavy metals. J. biophys. biochem. Cytol. 4, 475–478 (1958).

    Google Scholar 

  • Weiss, L. P., Kwan-Chung Tsou and A. M. Seligman: Histochemical demonstration of protein-bound amino groups. J. Histochem. Cytochem. 2, 29–49 (1954).

    Google Scholar 

Download references

Author information

Authors and Affiliations


Rights and permissions

Reprints and permissions

About this article

Cite this article

Pedersen, K.J. Cytological studies on the planarian neoblast. Zeitschrift für Zellforschung 50, 799–817 (1959).

Download citation

  • Received:

  • Issue Date:

  • DOI: