Zeitschrift für Parasitenkunde

, Volume 47, Issue 2, pp 91–101 | Cite as

Ultrastructural development of first- to second-generation merozoites in Eimeria contorta Haberkorn, 1971

  • Bodo E. G. Müller
Article
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Summary

The development of first-generation merozoites to second-generation schizonts and merozoites of Eimeria contorta in one of its natural hosts, the mouse, was investigated with the electron microscope. Merozoites inside a host cell show a marked U-shape and a degeneration of the inner pellicular membrane complex prior to transformation into schizonts. These processes closely resemble those seen in transforming sporozoites. In young schizonts with about 3–5 nuclei, the Golgi-adjuncts (structures of unknown function) form a large interconnected network.

Nuclear divisions in growing schizonts involve the formation of a centrocône, which develops in a pocket-like indentation of the nuclear envelope. At least one centriole is present immediately adjacent to this indentation. In a later stage, the centrocône forms a conical nuclear protrusion directed towards a merozoite-anlage. This developing merozoite contains anlagen of a conoid, of rhoptries, and of micronemes and a refractile body in addition to the nucleus, centrioles, and a Golgi-adjunct. The merozoite-anlage is limited by a triple unit membrane complex.

Schizonts give rise to 8–15 second-generation merozoites. Interesting features of these merozoites are the high number of micronemes, the finding of one single large mitochondrion per merozoite, and the occurrence of 26 subpellicular microtubules, i.e. the same number as in sporozoites of E. contorta. At the end of their development, merozoites come into direct contact with the host cell cytoplasm as the parasitophorous vacuole breaks down.

Keywords

Host Cell Nuclear Envelope Natural Host Interconnected Network Nuclear Division 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
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Copyright information

© Springer-Verlag 1975

Authors and Affiliations

  • Bodo E. G. Müller
    • 1
    • 2
  1. 1.Abteilung für ProtozoologieZoologisches Institut der Universität BonnGermany
  2. 2.Fakultät für Biologie der UniversitätBielefeldFederal Republic of Germany

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