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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Ref ID : 4690

Josef Dieckmann; [Podophrya grelli n. sp., ein wirtsspezifisches Suktor, parasitierend auf Stylonychia lemnae Ammermann und Schlegel 1983] (Podophrya grelli n. sp., a Host-Specific Suktor Parasitic on Stylonychia lemnae Ammermann und Schlegel 1983). Arch.Protistenk 129:155-170, 1985

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Podophrya grelli n. sp., a host-specific ectoparasite of Stylonychia lemnae Ammermann and Schlegel, 1983 is described. Podophrya grelli has a life cycle with an alternation of generations. The infection is performed by an oval, ciliated swarmer (15-20 µm), which attaches with some tentacles at the host cell. The swarmer deciliates and induces the host cell to form a pellicular invagination accommodating the suctor. The invagination remains open to the culture medium. The swarmer rounds up, ingests the host cytoplasm by means of its tentacles and grows to the adult parasite (30-50 µm). By inequal, in rare cases equal divisions new swarmers are formed. These leave the invagination and can infect new host cells. After a host cell degenerated due to the continuous loss of cytoplasm some parasites conjugate. One to 3, maximally 5 conjugating pairs per cell are formed. Increasing the food uptake the conjugants store granular material and grow considerably. The conjugants then get into the culture medium, remaining connected for some time at the bottom of the culture vessel before they separate. Exconjugants form a stalked cyst. By successive multiple fissions within the cyst up to 16 infectious swarmers are formed, which cannot be distinguished with the light microscope from the swarmers of the asexual generation. As the result of an infection by Podophrya grelli the host cell loses the ability to divide, conjugate and encyst. Due to the continuous loss of cytoplasm the cell and the nuclei rapidly degenerate leading to the death of the host cell. Podophrya grelli is host-specific and only infects stocks of Stylonychia lemnae. Tests to infect a number of other ciliate species were unsuccessful.