Abstract
Structural and functional characteristics of the reticular cell in the planarian Dugesia dorotocephala were studied by light and electron microscopy. Since the reticular cells have numerous glycogen granules, lipid droplets and some lysosomes in their cytoplasm, they are easily distinguishable from other cell types. They migrate into the injured tissue, cover the injured mesenchyme, and also phagocytize debris of degenerating cells. The reticular cells also recognize foreign invaders such as bacteria. The larger aggregates of killed bacteria are encapsulated by reticular cells and eliminated into the intestine, whereas small aggregates are phagocytized by reticular cells. When cell wall extract of bacteria was inserted into the planarian body before insertion of killed bacteria, reticular cells were found to respond more quickly and vigorously to subsequent insertion of killed bacteria, indicating that the reticular cell has an immune response memory. When planarians were treated with 0.3 ppm cadmium sulfate and 0.01 ppm TPA, reticuloma tumors were induced in 76% of exposed planarians, indicating the similarity to blood cell diseases in mammals such as leukemia or lymphoma which are also induced by TPA. When these tumors were transplanted into normal hosts, the tumor cells were attacked by host reticular cells. These observations indicate that planarian reticular cells are primitive blood cells, playing important roles in nutrient transportation, homeostatic control of cells, and in defence and immune surveillance systems.
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References
Andrew, W., 1965. Comparative aspects of blood invertebrates. In W. Andrew (ed.), Comparative Hematology. Greene and Stratton, New York: 62–68.
Armuth, V. & I. Berenblum, 1974. Promotion of mammary carcinogenesis and leukemogenic action by phorbol in virgin female Wistar rats. Cancer Res. 34: 2704–2707.
Berenblum, I. & V. Lonai 1970. The leukemogenic action of phorbol. Cancer Res. 30: 2744–2748.
Hall, F. L., M. Morita & J. B. Best, 1986a. Neoplastic transformation in the planarian. I. Cocarcinogenesis and histopathology. J. exp. Zool. 240: 211–227.
Hall, F. L., M. Morita & J. B. Best, 1986b. Neoplastic transformation in the planaria. II. Ultrastructure of malignant reticuloma. J. exp. Zool. 240: 229–244.
Hori, I., 1991. Role of fixed parenchyma cells in blastema formation of the planarian Dugesia japonica. Int. J. dev. Biol. 35: 101–108.
Ishii, S., 1965. Electron microscopic observations on the planarian tissue. II. The intestine. Fukushima J. med. Sci. 12: 67–87.
Morita, M., 1967. Observations on the fine structure of the neoblast and its cell division in the regenerating planaria. Sci. Rep. Tohoku Univ. Biol. 33: 339–406.
Morita, M., 1991. Phagocytic response of the planarian reticular cells to heat-killed bacteria. Hydrobiologia 227 (Dev. Hydrobiol. 69): 193–199.
Morita, M. & J. B. Best, 1974. Electron microscopic studies of planarian regeneration. II. Changes in epidermis during regeneration. J. exp. Zool. 187: 345–374.
Morita, M. & J. B. Best, 1984. Electron microscopic studies of planarian regeneration. III. Degeneration and differentiation of muscles. J. exp. Zool. 229: 425–436.
Morita, M., & J. B. Best & J. Noel, 1969. Electron microscopic studies of planarian regeneration. I. Fine structure of neoblasts in Dugesia dorotocephala J. ultrastruc. Res., 27: 7–23.
Pedersen, K. J., 1959. Cytological studies on the planarian neoblast. Z. Zellforsch. mikroskop. Anat. 50: 700–817.
Pedersen, K. J., 1961. Studies on the nature of planarian connective tissue. Z. Zellforsch. mikroskop. Anat. 53: 569–608.
Sato, T., 1968. A modified method for lead staining of thin sections. J. electron Microsc., 17: 158–159.
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Morita, M. (1995). Structure and function of the reticular cell in the planarian Dugesia dorotocephala . In: Cannon, L.R.G. (eds) Biology of Turbellaria and some Related Flatworms. Developments in Hydrobiology, vol 108. Springer, Dordrecht. https://doi.org/10.1007/978-94-011-0045-8_32
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DOI: https://doi.org/10.1007/978-94-011-0045-8_32
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