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Hydrobiologia

, Volume 305, Issue 1–3, pp 207–212 | Cite as

The ultrastructure of the germanium in some Rhabdocoela

  • Paolo Lucchesi
  • Alessandra Falleni
  • Vittorio Gremigni
Anatomy and ultrastructure

Abstract

Ultrastructure features of the germanium (ovary) have been investigated in several species of Rhabdocoela. The gonad is usually unpaired, small and pear-shaped; it is enveloped by an extracellular lamina and contains oocytes at different stages of maturation. Elongate accessory cells surround germ cells in the peripheral zone of the gonad and can also fill the internal spaces between oocytes with their long, flattened processes. The main features observed during oocyte maturation were the appearance of chromatoid bodies, annulate lamellae, lipid droplets and glycogen particles, and the development of R.E.R. and Golgi complexes which appeared correlated with the production of small inclusions that became localized in the cortical ooplasm of mature germ cells. The inclusions exhibited a different structure in different taxa and contained variable amounts of polyphenols. Cortical inclusions of rhabdocoels most probably represent residual shell-granules and may participate in the capsule-shell formation.

Key words

Rhabdocoela Platyhelminthes germanium ovary oocyte cortical inclusions ultrastructure 

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References

  1. Anderson, A. & J. André, 1968. The extraction of some cell components with pronase and pepsin from thin sections of tissue embedded in Epon-Araldite mixture. J. Microscopie 7: 343–345.Google Scholar
  2. Ax, P., 1987. The phylogenetic system. The systematization of organisms on the basis of their phylogenesis. J. Wiley & Sons, Chichester, 249 pp.Google Scholar
  3. Cannon, L. R. G., 1986. Turbellaria of the world. A guide to families & genera. Brisbane: Queensland Museum, 131 pp.Google Scholar
  4. Cifrian, B., S. martinez-Alõs & V. Gremigni, 1993. Ultrastructural and cytochemical studies of the germanium of Dicrocoelium dendriticum (Plathelminthes, Digenea). Zoomorphology 113: 165–171.Google Scholar
  5. Davis, R. E. & L. S. Roberts, 1983. Platyhelminthes-Eucestoda. In K. G. Adiyodi & R. G. Adiyodi (eds), Reproductive Biology of Invertebrates. Vol. 1, Oogenesis, oviposition and oosorption. J. Wiley & Sons, Chichester: 109–133.Google Scholar
  6. Domenici, L. & V. Gremigni, 1977. Fine Structure and functional role of the coverings of the eggs in Mesostoma ehrenbergii (Focke) (Turbellaria, Neorhabdocoela). Zoomorphology 88: 247–257.Google Scholar
  7. Ehlers, U., 1985. Phylogenetic relationships within the Platyhelminthes. In S. Conway Morris, J. D. George, R. Gibson & H. M. Platt (eds), The origins and relationships of lower invertebrates. Oxford University Press, Oxford: 143–158.Google Scholar
  8. Falleni, A. & V. Gremigni, 1992. An ultrastructural study of growing oocytes in Nematoplana riegeri (Platyhelminthes). J. Submicrosc. Cytol. Pathol. 24: 51–59.Google Scholar
  9. Falleni, A. & P. Lucchesi, 1992. Ultrastructural and cytochemical aspects of oogenesis in Castrada viridis (Platyhelminthes, Rhabdocoela). J. Morphol. 213: 241–250.Google Scholar
  10. Gremigni, V., 1983. Platyhelminthes-Turbellaria. In K. G. Adiyodi & R. G. Adiyodi (eds), Reproductive Biology of Invertebrates. Vol. 1. Oogenesis, oviposition and oosorption. J. Wiley & Sons, Chichester, 67–107.Google Scholar
  11. Gremigni, V., 1988. A comparative ultrastructural study of homocellular and heterocellular female gonads in free living Platyhelminthes-Turbellaria. Fortschr. Zool. 36: 245–261.Google Scholar
  12. Gremigni, V. & L. Domenici, 1977. On the role of specialized, peripheral cells during embryonic development of subitaneous eggs in the turbellarian Mesostoma ehrenbergii (Focke): an ultrastructural and autoradiographic investigation. Acta Embryol. Morphol. Exper. 2: 251–265.Google Scholar
  13. Gremigni, V. & A. Falleni, 1992. Mechanism of shell-granule and yolk production in oocytes and vitellocytes of Platyhelminthes-Turbellaria. Anim. Biol. 1: 29–37.Google Scholar
  14. Gremigni, V. & M. Nigro, 1983. An ultrastructural study of oogenesis in a marine triclad. Tissue Cell 15: 405–415.Google Scholar
  15. Gremigni, V. & M. Nigro, 1984. Ultrastructural study of oogenesis in Monocelis lineata (Turbellaria, Proseriata). Int. J. Invert. Reprod. Devel. 7: 105–118.Google Scholar
  16. Guraya, S. S. & V. R. Parshad, 1988. Platyhelminthes. In K. G. Adiyodi and R. G. Adiyodi (eds), Reproductive Biology of Invertebrates. Vol. 3. Accessory sex glands. J. Wiley & Sons, Chichester: 1–49.Google Scholar
  17. Locke, M. & N. Krishnan, 1971. The distribution of polyphenoloxidases and polyphenols during cuticle formation. Tissue Cell 3: 103–126.Google Scholar
  18. Martinez-Alõs, S., B. Cifrian & V. Gremigni, 1993. Ultrastructural investigations on the vitellaria of digenean Dicrocoelium dendriticum. J. Submicrosc. Cytol. Pathol. 25: 583–590.Google Scholar
  19. Nigro, M. & V. Gremigni, 1987. Ultrastructural features of oogenesis in a free-living marine platyhelminth, Vorticerods luteum. Tissue Cell 19: 377–386.Google Scholar
  20. Rieger, R. M., S. Tyler, J. P. S. Smith & G. E. Rieger, 1991. Platyhelminthes: Turbellaria. In F. W. Harrison & B. J. Bogitsh (eds), Microscopic Anatomy of Invertebrates. Vol. 3. Platyhelminthes and Nemertinea. Wiley-Liss, Inc., New York: 7–140.Google Scholar
  21. Shinn, G. L., 1993. Formation of egg capsules by flatworms (Phylum Platyhelminthes). Trans. am. Microsc. Soc. 112: 18–34.Google Scholar
  22. Shinn, G. L. & R. A. Cloney, 1986. Egg capsules of a parasitic turbellarian flatworm: ultrastructure of hatching sutures. J. Morphol. 188: 15–28.Google Scholar
  23. Smith, J. P. S., S. Tyler & R. M. Rieger, 1986. Is the Turbellaria polyphyletic? Hydrobiologia 132: (Dev. Hydrobiol. 32): 13–21.Google Scholar
  24. Smyth, S. D. & D. W. Halton 1983. The Physiology of Trematodes. Cambridge University Press, Cambridge, 417 pp.Google Scholar
  25. Sopott-Ehlers, B. & U. Ehlers, 1986. Differentiation of male and female germ cells in neoophoran Plathelminthes. In M. Porchet, J. C. Andries & A. Dhainaut (eds), Advances in Invertebrate Reproduction 4. Elsevier Science Publ., Amsterdam: 187–194.Google Scholar
  26. Thiéry, J. P., 1967. Mise en évidence des polysaccharides sur coupes fines en microscopie électronique. J. Microscopie 6: 987–989.Google Scholar
  27. Xylander, W. E. R., 1987. Ultrastructural studies on the reproductive system of Gyrocotylidea and Amphilidea (Cestoda). II. Vitellaria, vitellocyte development and vitelloduct of Gyrocotyle urna. Zoomorphology 107: 293–297.Google Scholar

Copyright information

© Kluwer Academic Publishers 1995

Authors and Affiliations

  • Paolo Lucchesi
    • 1
  • Alessandra Falleni
    • 1
  • Vittorio Gremigni
    • 1
  1. 1.Dipartimento di Biomedicina Sperimentale, Sez. Biologia e Genetica, via A. Volta 4Universitá di PisaPisaItaly

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