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1

Isolation of the Amoeba Thecamoeba quadrilineata Harbouring Intranuclear Spore Forming Endoparasites Considered as Fungus-like Organisms

100%

Michel R., HAURÖDER B., ZÖLLER L.

Acta Protozoologica

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2009

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vol. 48

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issue 1

PL

Among a population of Thecamoeba quadrilineata (Thecamoebidae) isolated from moss samples some trophozoites harboured intracellular aggregates of round-oval parasites which turned out to be spores with a real nucleus. These organisms were supposed to be fungal endoparasites beginning their development within the nucleus of the host invaded by young parasitic stages after the host amoeba had engulfed free spores from the environment. The complete developmental cycle was studied by electron microscopy, showing the intranuclear growth of freshly invaded young stages into large spore forming parasites differentiating into a great number of spores – all within the border of the host’s nuclear membrane. These spores were not released into the environment until the death and decay of the host amoeba, where they could be ingested as infective stages by hitherto not infected thecamoebae. Host range studies with various free-living amoebae (FLA) showed that T. striata and T. terricola were as permissive to infection as the original host T. quadrilineata. Sappinia was only susceptible to a certain extent and therefore not considered as possible natural host. Remarkably, this observation shows that both nuclei of the bi-nucleate amoeba became simultaneously infected. The present morphological description corresponds to early observations with fungal intranuclear parasites called Nucleophaga Dangeard, 1887. However, genetic and phylogenetic studies have to corroborate the supposed fungal nature.

2

Electron Microscopical Investigations of a New Species of the Genus Sappinia (Thecamoebidae, Amoebozoa), Sappinia platani sp. nov., Reveal a Dictyosome in this Genus

88%

WYLEZICH C., Kudryavtsev A., Michel R., Corsaro D., Walochnik J.

Acta Protozoologica

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2015

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vol. 54

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issue 1

PL

The genus Sappinia belongs to the family Thecamoebidae within the Discosea (Amoebozoa). For long time the genus comprised only two species, S. pedata and S. diploidea, based on morphological investigations. However, recent molecular studies on gene sequences of the small subunit ribosomal RNA (SSU rRNA) gene revealed a high genetic diversity within the genus Sappinia. This indicated a larger species richness than previously assumed and the establishment of new species was predicted. Here, Sappinia platani sp. nov. (strain PL-247) is described and ultrastructurally investigated. This strain was isolated from the bark of a sycamore tree (Koblenz, Germany) like the re-described neotype of S. diploidea. The new species shows the typical characteristics of the genus such as flattened and binucleate trophozoites with a differentiation of anterior hyaloplasm and without discrete pseudopodia as well as bicellular cysts. Additionally, the new species possesses numerous endocytobionts and dictyosomes. The latter could not be found in previous EM studies of the genus Sappinia. Standing forms, a character of the species S. pedata, could be formed on older cultures of the new species but appeared extremely seldom. A loose layer of irregular, bent hair-like structures cover the plasma membrane dissimilar to the glycocalyx types as formerly detected in other Sappinia strains.

3

Molecular Identification of a Phage-infected Protochlamydia Strain Naturally Harboured by Non-Encysting Naegleria

88%

Corsaro D., Walochnik J., Venditti D., Müller K.-D., Michel R.

Acta Protozoologica

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2013

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vol. 52

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issue 4

PL

A thermophilic strain of Naegleria clarki, isolated from a pond, has previously been investigated for its peculiarity to host a cytoplasmic symbiont, which causes a loss of the ability to form cysts. This endosymbiont, called Pcb, was itself infected by a phage, and exhibited chlamydia-like features resembling to another symbiont of Naegleria previously described as Protochlamydia naegleriophila. We report in this study, the results of amoeba host range and 16S rDNA molecular phylogeny of this strain, showing that Pcb is a new strain of the Naegleria endosymbiont chlamydial species Protochlamydia naegleriophila (Chlamydiae: Parachlamydiaceae).

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Isolation of the Amoeba Thecamoeba quadrilineata Harbouring Intranuclear Spore Forming Endoparasites Considered as Fungus-like Organisms

Electron Microscopical Investigations of a New Species of the Genus Sappinia (Thecamoebidae, Amoebozoa), Sappinia platani sp. nov., Reveal a Dictyosome in this Genus

Molecular Identification of a Phage-infected Protochlamydia Strain Naturally Harboured by Non-Encysting Naegleria