In vitro excystment of the metacercaria of Cryptocotyle concavum from the common goby Pomatoschistus microps | Journal of Helminthology | Cambridge Core (original) (raw)

Abstract

The metacercaria of the heterophyid digenean Cryptocotyle concavum (Creplin, 1825) Lühe 1899, as seen by light and transmission electron microscopy, from the common goby (Pomatoschistus microps) is enclosed within a rigid cyst wall composed of four layers of parasite origin surrounded by a host-derived capsule. The encysted parasite contains anterior glands with secretion-filled ducts opening at the anterior extremity of the ‘head’. Excystment in vitro occurred most readily at 40–42°C on treatment with alkaline bile salts following pretreatment with acid pepsin. After 1 min in pepsin, the metacercaria became intermittently active, periods of rotation lasting 1–3 sec alternating with quiescent periods of 20–40 sec. Metacercariae excysted, some in less than 1 min, after transfer to bile salts. The metacercaria emerged through a hole, which appeared in the cyst wall at the site of application of the ‘head’ of the parasite. Some of the anterior gland ducts of excysted metacercariae were empty, indicating that their secretions are involved in penetrating the cyst wall. Following pretreatment in acid pepsin, no excystment occurred in EBSS (Earle's balanced salt solution) ranging in pH from 2.0 to 4.0, but above pH 4.0, excystment increased, reaching a maximum between pH 7.5 and 8.5. Pepsin and bile salts were not essential for excystment and metacercariae emerged, although less readily, in alkaline EBSS with or without acid EBSS pretreatment. Some emerged in distilled water with no pretreatment. Although no excystment occurred in acid pepsin or in EBSS at pH 2.0 and already-excysted metacercariae were rapidly killed by acid (pH 2.0), acid pepsin pretreatment enhanced excystment in alkaline bile salts.

References

Asanji, M.F. & Williams, M.O. (1975) Studies on the excystment of trematode metacercariae in vitro. Zeitschrft für Parasitenkunde 47, 151–163.CrossRefGoogle ScholarPubMed

Asanji, M.F. & Fried, B.. (1990) Excystation of five digenean metacercariae in vitro and in the peritoneal cavity of the mouse. International Journal for Parasitology 20, 257–258.CrossRefGoogle ScholarPubMed

Bass, H.S. & Leflore, W.B.. (1984) In vitro excystment of the metacercaria of Echinoparyphium spinulosum (Trematoda: Echinostomatidae). Proceedings of the Helminthological Society of Washington 5, 149–153.Google Scholar

Bock, D. (1986) In vitro excystment of the metacercaria of Plagiorchis species 1 (Trematoda, Plagiorchidae). International Journal for Parasitology 16, 641–645.CrossRefGoogle Scholar

Bock, D. (1988) Formation of the cyst wall and ultrastructure of the metacercarial cyst wall of Plagiorchis species 1 (Trematoda, Plagiorchidae). International Journal for Parasitology 18, 379–388.CrossRefGoogle Scholar

Bock, D. (1989) Hatching mechanism of the metacercaria of Plagiorchis species 1 (Trematoda Plagiorchidae). Journal of Helminthology 63, 153–171.CrossRefGoogle Scholar

Caley, J. (1975) A comparative study of the two alternative larval forms of Hymenolepis nana, the dwarf tapeworm, with a special reference to the process of excystment. Zeitschr!ft für Parasitenkunde 47, 271–285.Google Scholar

Ciurea, I. (1933a) Les vers parasite de l'homme des mammifères et des oiseaux provenant des poissons du Danube et de la Mer Noire. Archives Roumaines de Pathologie Expérimentale et de Microbiologie 4, 289–299.Google Scholar

Ciurea, I. (1933b) Sur quelques larves des vers parasites de l'homme, des mammifères et des oiseaux ichtyophages trouvés chez les poissons des grands lacs de la Bessarable, du Dniester et de son liman. Archives Roumaines de Pathologie Expérimentale et de Microbiologie 6, 161–170.Google Scholar

Dixon, K.E. (1966) The physiology of excystment of the metacercaria of Fasciola hepatica. L.. Parasitology, 56,431–456.CrossRefGoogle ScholarPubMed

Dunn, T.S., Ownbey, T.C. & Vannarath, T. (1990) In vitro excystment of the metacercaria of Gynaecotyle adunca and Probolocoryphe uca (Microphallidae) from the fiddler crab Uca pugilator. Canadian Journal of Zoology 68, 2376–2384.CrossRefGoogle Scholar

Ferguson, M.A. (1940) Excystment and sterilisation of the metacercaria of the avian strigeid trematode Posthodiplostomum minimum and their development into adult worms in sterile cultures. Journal of Parasitology 26, 359–372.CrossRefGoogle Scholar

Fried, B. & Emili, S. (1988) Excystation in vitro of Echinostoma liei and E. revolutum (Trematoda) metacercariae. Journal of Parasitology 74, 98–102.CrossRefGoogle Scholar

Fried, B., LeFlore, W.B. & Bass, H.S. (1984) Histochemical localization of hydrolytic enzymes in the cercaria and excysted metacercaria of Echinostoma revolutum (Trematoda). Proceedings of the Helminthological Society of Washington 51, 140–143.Google Scholar

Gulka, G.J. & Fried, B. (1979) Histochemical and ultrastructural studies on the metacercarial cyst of Echinostoma revolutum (Trematoda). International Journal for Parasitology 9, 57–59.CrossRefGoogle ScholarPubMed

Hoffman, G.L. (1957) Studies on the life cycle of Cryptocotyle concavum from the common sucker and experimentally in the chick. Proceedings of the North Dakota Academy of Science 11, 55–56.Google Scholar

Howell, M.J. (1970) Excystment of the metacercariae of Echinoparyphium serratum (Trematoda: Echinostomatidae). Journal of Helminthology 44, 35–56.CrossRefGoogle ScholarPubMed

Irwin, S.W.B. (1983) In vitro excystment of the metacercaria of Maritrema arenaria (Digenea: Microphallidae). International Journal for Parasitology 13, 191–196.CrossRefGoogle Scholar

Irwin, S.W.B., McShane, G. & Saville, D.H. (1989) A study of metacercarial excystment in Parapronocephalum symmetricum (Trematoda: Notocotylidae). Parasitology Research 76, 45–49.CrossRefGoogle Scholar

Issaitschikoff, I.M. & Weinberg, M. (1926) Sur le développement du Trématode Cryptocotyle concavum (Creplin). Compte Rendu des Séances de Ia Société de Biologie 94, 305–308.Google Scholar

Kearn, G.C., Cleveland, G. & Wilkins, S. (1989) An in vitro study of the forcible ejection of the metacercaria of the strigeid digenean Apatemon (Australapatemon) minor Yamaguti, 1933, by rapid inward expansion of the cyst wall. Journal of Helminthology 63, 63–71.CrossRefGoogle Scholar

Lackie, A.M. (1975) The activation of infective stages of endoparasites of vertebrates. Biological Reviews 50, 285– 323.CrossRefGoogle ScholarPubMed

Larson, O.R., Uglem, G.L. & Lee, K.J. (1988) Fine structure and permeability of the metacercarial cyst wall of Clinostomum marginatum (Digenea). Parasitology Research 74, 352–355.CrossRefGoogle ScholarPubMed

LeFlore, W.B. & Bass, H.S. (1983) Observations on morphology and hydrolytic enzyme histochemistry of excysted metacercariae of Himasthla rhigedana (Trematoda: Echinostomatidae). International Journal for Parasitology 13, 179–183.CrossRefGoogle Scholar

Lumsden, R.D. (1968) UItrastructure of the metacercarial cyst of Ascocotyle chandleri, Lumsden 1963 (Trematoda: Heterophyidae). Proceedings of the Helminthological Society of Washington 35, 212–218.Google Scholar

McDowall, A.A. (1985) Digenea of the common goby, Pomatoschistus microps (Kroyer, 1640). PhD Thesis. University of Wales (Swansea).Google Scholar

Rebecq, J. (1964) Recherches systématiques biologiques et écologiques sur les formes larvaires de quelques trématodes de Camargue. Thèse de Doctorat, Faculté des Sciences, Université de Aix-Marseille, France.Google Scholar

Reimer, L.W. (1970) Digenea Trematoden und Cestoden der Ostseefische als naturalische Fishmarken. Parasitologische Schriftenreihe 20, 1–144.Google Scholar

Schroeder, D.J., Johnson, A.D. & Mohammed, K.H. (1981) In vitro excystment of the blackspot trematode Neascus pyriformis Chandler, 1951 (Trematoda: Diplostomatidae). Proceedings of the Helminthological Society of Washington 48, 184–189.Google Scholar

Spellman, S.J. & Johnson, A.D. (1987) In vitro excystment of the blackspot trematode Uvulifer ambloplitis (Trematoda: Diplostomatidae). International Journal for Parasitology 17, 897–902.CrossRefGoogle Scholar

Stunkard, H.W. (1930) The life history of Cryptocotyle lingua (Creplin, 1825) with notes on the physiology of the metacercaria. Journal of Morphology and Physiology 50, 143– 184.CrossRefGoogle Scholar

Sukhdeo, M.V.K. & Mettrick, D.F. (1986) The behavior of juvenile Fasciola hepatica. Journal of Parasitology 72,492–497.CrossRefGoogle ScholarPubMed

Thompson, M. & Halton, D.W. (1982) Observations on excystment in vitro of Cotylurus variegatus metacercariae (Trematoda: Strigeidae). Zeitschrift für Parasitenkunde 68, 201–209.CrossRefGoogle Scholar

Venard, C.E. (1938) Morphology bionomics and taxonomy of the cestode Dipylidium caninum. Annals of the New York Academy of Sciences 37, 273.CrossRefGoogle Scholar

Wootton, D.M. (1957) The life history of Cryptocotyle concavum (Creplin, 1825), Fischoeder, 1903 (Trematoda: Heterophyidae). Journal of Parasitology 43, 271–279.CrossRefGoogle ScholarPubMed

Yokogawa, S., Cort, W.W. & Yokogawa, N. (1960) Paragonimus and paragonimiasis. Experimental Parasitology 10, 81–202.CrossRefGoogle Scholar

Yamaguti, S. (1975) A synoptical review of life histories of digenetic trematodes of vertebrates with special references to the morphology of their larval forms. 590 pp. Tokyo, Keigaku Publishing Company.Google Scholar

Zänder, C.D., Krolla, H.G., Antholz, B., Meyer, W. & Westphal, D. (1984) Small-sized euryhaline fish as intermediate hosts of the digenetic trematode Cryptocotyle conawum. Helgoländer wissenschaftliche Meeresuntersuchungen, 37, 433–443.CrossRefGoogle Scholar