Hostname: page-component-586b7cd67f-dlnhk Total loading time: 0 Render date: 2024-11-23T22:52:04.640Z Has data issue: false hasContentIssue false
  • English
  • Français

Observations on the epidermis of the miracidium and on the formation of the tegument of the sporocyst of Fasciola hepatica

Published online by Cambridge University Press:  06 April 2009

V. R. Southgate
V. R. Southgate
Affiliation:
The Molteno Institute, University of Cambridge
Get access Rights & Permissions [Opens in a new window]

Extract

The relationship between the ciliated epidermal cells and the subepidermal layer of the miracidium of Fasciola hepatica has been described. Non-ciliated ridge-like extensions of the subepidermal layer separate the ciliated epidermal cells from each other. The sunken portions of the subepidermal layer, each containing a nucleus, lie below the outer body wall muscles of the miracidium and open into the ridge by narrow neck-like connexions. Elongate vesicles, which may be a source of stored plasma membrane similar to that which occurs in the transitional epithelium of other animals, fill most of the ridge. In addition, characteristic round electron dense granules are found in the ridge but the majority are found in the sunken portions of the subepidermal layer.

The development and origins of the tegument of the sporocyst of F. hepatica have been described at the ultrastructural level. When the miracidium is in the process of penetrating the snail host, large vacuoles appear between the ciliated epidermal cells and the basal lamina which overlies the muscles of the body wall. These vacuoles have the effect of loosening the epidermal cells from the basal lamina of the body wall of the miracidium. Possible mechanisms involved in the formation of such vacuoles are suggested and discussed.

During penetration of the snail the ciliated epidermal cells of the miracidium are lost; the ridge, a syncytial layer between the epidermal cells which is connected with the subepidermal layer, spreads over the basal lamina and exposed body wall muscles of the metamorphosing sporocyst to form the new outer covering of the sporocyst.

Cytoplasm passes from the subtegumentary layer into the tegument during this stage of the development of the body wall of the sporocyst. Muscular contraction and microtubules may be involved in the outward movements of this cytoplasm. The nuclei of the subtegumentary layer remain below the muscles of the body wall.

Twenty-four hours after penetration of the snail the outer plasma membrane of the tegument forms folds, which greatly increase the surface area.

Sixty hours after penetration involutions between the folds, which may indicate pinocytosis, are present, and it is suggested that pinocytosis may play a role in food absorption.

The fully formed tegument is a syncytial layer containing numerous electron dense granules, vacuoles, mitochondria and lipid droplets.

The results on the formation of the tegument of the sporocyst have been discussed with reference to the controversy about the origins and terminology of the outer covering of the Platyhelminths.

Type
Research Article
Information
Parasitology , Volume 61 , Issue 2 , October 1970 , pp. 177 - 190
Copyright
Copyright © Cambridge University Press 1970

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Belton, C. M. & Harris, P. J. (1967). Fine structure of the cuticle of the cercaria of Acanthatrium oregonense (Macy). Journal of Parasitology 53, 715–24.CrossRefGoogle ScholarPubMed
Bils, R. F. & Martin, W. E. (1966). Fine structure and development of the trematode integument. Transactions of the American Microscopical Society 85, 78–88.CrossRefGoogle ScholarPubMed
Birkle, D., Tilney, L. G. & Porter, K. R. (1966). Microtubules and pigment migration in the melanophores of Fundulus heteroclitus. Protoplasma 61, 322–45.CrossRefGoogle Scholar
Burton, P. R. (1964). The ultrastructure of the integument of the frog lung-fluke, Haematoloechus medioplexus (Trematoda: Plagiorchiidae). Journal of Morphology 115, 305–18.CrossRefGoogle ScholarPubMed
Burton, P. R. (1966). The ultrastructure of the integument of the frog bladder fluke, Gorgoderina sp. Journal of Parasitology 52, 926–34.CrossRefGoogle ScholarPubMed
Coe, W. R. (1896). Notizen uber den Bau des Embryos von Distomum hepaticum. Zoologische Jahrbucher Anatomie und Ontogenie der Tiere 9, 561–71.Google Scholar
Dawes, B. (1960). A study of the miracidium of Fasciola hepatica and an account of the mode of penetration of the sporocyst into Lymnaea truncatula. In Libro Homenage al Dr Eduardo Caballero y Caballero. Jubileo 1930–60, 95–111. Mexico: Escuela Nacional de Ciencias Biologicas.Google Scholar
Dixon, K. E. & Mercer, E. H. (1967). The formation of the cyst wall of the metacercaria of Fasciola hepatica L. Zeitschrift für Zellforschung und mikroskopische Anatomie 77, 345–60.CrossRefGoogle ScholarPubMed
Dorey, A. E. (1965). The organisation and replacement of the epidermis in acoleus turbellarians. Quarterly Journal of Microscopical Science 106, 147–72.Google Scholar
Fawcett, D. W. (1966). An Atlas of Fine Structure: The Cell: Its Organelles and Inclusions. Philadelphia and London: W. B. Saunders.Google Scholar
Hyman, L. H. (1951). The Invertebrates: Platyhelminthes and Rhynchocoela. The Acoelomate Bilateria, vol. 2. New York: McGraw-Hill.Google Scholar
James, B. L., Bowers, E. A. & Richards, J. G. (1966). The ultrastructure of the daughter sporocyst of Cercaria bucephalopsis haimaena Lacaze-Duthiers, 1854 (Digenea: Bucephalidae) from the edible cockle, Cardium edule L. Parasitology 56, 753–62.CrossRefGoogle ScholarPubMed
Ledbetter, M. C. & Porter, K. R. (1963). A ‘microtubule’ in plant cell fine structure. Journal of Cell Biology 19, 239–50.CrossRefGoogle ScholarPubMed
Lee, D. L. (1966). The structure and composition of the helminth cuticle. In Advances in Parasitology. Ed. Dawes, B.. 4, 187–254. London and New York: Academic Press.Google Scholar
Mattes, O. (1949). Wirtsfindung, invasionsvorgang und wirtsspezifitat beim Fasciola miracidium. Zeitschrift für Parasitenkunde 14, 320–63.CrossRefGoogle Scholar
Mercer, E. H. & Dixon, K. E. (1967). The fine structure of the cystogenic cells of the cercaria of Fasciola hepatica L. Zeitschrift für Zellforschung und mikroskopische Anatomie 77, 331–44.CrossRefGoogle ScholarPubMed
Millonig, G. (1961). A modified procedure for lead staining of thin sections. Journal of Biophysical and Biochemical Cytology 11, 736–9.CrossRefGoogle ScholarPubMed
Noble-Nesbitt, J. (1963). The cuticle and associated structures of Podura aquatica at the moult. Quarterly Journal of Microscopical Science 104, 369–91.Google Scholar
Ortmann, W. (1908). Zur embryon al entwicklung des heberegels (Fasciola hepatica L.) Zoologische Jahrbucher Anatomie und Ontogenie der Tiere 26, 255–92.Google Scholar
Oschman, J. L. (1967). Microtubules in the sub-epidermal glands of Convoluta roscoffiensis (Acoela, Turbellaria). Transactions of the American Microscopical Society 86, 159–62.CrossRefGoogle Scholar
Pantelouris, E. M. (1965). The Common Liver Fluke Fasciola hepatica L. Oxford: Pergamon Press.Google Scholar
Pease, D. C. (1960). The basement membrane: substratum of histological order and complexity. In Fourth International Conference on Electron Microscopy. Ed. Bargmann, W.. 139–55. Berlin: Springer-Verlag.Google Scholar
Porter, K. R. & Bonneville, M. A. (1964). An Introduction to the Fine Structure of Cells and Tissues. Philadelphia: Lea and Febiger.Google Scholar
Rees, F. G. (1966). Light and electron microscope studies of the redia of Parochis acanthus Nicoll. Parasitology 56, 589–602.CrossRefGoogle Scholar
Rees, F. G. (1967). The histochemistry of the cystogenous gland cells and cyst wall of Parorchis acanthus Nicoll, and some details of the morphology and fine structure of the cercaria. Parasitology 57, 87–110.CrossRefGoogle Scholar
Reynolds, E. S. (1963). Lead citrate at high pH as an electron opaque stain. Journal of Cell Biology 17, 208–12.CrossRefGoogle ScholarPubMed
Rosenbluth, J. (1965). Ultrastructural organisation of obliquely striated muscle fibres in Ascaris lumbricoides. Journal of Cell Biology 25, 495–515.CrossRefGoogle ScholarPubMed
Schubmann, W. (1905). Uber die eibildung und embryonalentwicklung von Fasciola hepatica L. Zoologische Jahrbucher Anatomie und Ontogenie der Tiere 21, 571–606.Google Scholar
Southgate, V. R. (1969). Studies on the biology and host-parasite relationships of some larval Digenea. Ph.D. thesis, University of Cambridge.Google Scholar
Taylor, E. L. & Mozley, A. (1948). A culture method for Lymnaea truncatula. Nature, London 161, 894.CrossRefGoogle ScholarPubMed
Thomas, A. P. (1883). The life history of the liver fluke. Quarterly Journal of Microscopical Science 23, 99–133.Google Scholar
Threadgold, L. T. (1963). The tegument and associated structures of Fasciola hepatica. Quarterly Journal of Microscopical Science 104, 505–12.Google Scholar
Tilney, L. G. & Porter, K. R. (1965). Studies on microtubules in Heliozoa. I. The fine structure of Actinosphaerium nucleofilium (Barrett), with particular reference to the axial rod structure. Protoplasma 60, 317–44.CrossRefGoogle Scholar
Wajdi, N. (1966). Penetration by the miracidia of S. mansoni into the snail host. Journal of Helminthology 40, 235–44.CrossRefGoogle ScholarPubMed
Wilson, R. A. (1969). Fine structure of the tegument of the miracidium of Fasciola hepatica L. Journal of Parasitology 55, 124–34.CrossRefGoogle ScholarPubMed