Archiv für Protistenkunde最新文献

The large, branched macronucleus of the suctorian ciliate Heliophrya erhardi has a dramatic regenerative/reorganizational capacity. Mechanical manipulation can break the large branched macronucleus into small fragments. Over a period of 3 days the macronucleus reorganizes through fusion of these fragments, forming a single new branched macronucleus. Pulsating vacuoles and feeding tentacles regenerate as well after mechanical destruction.

Two isosporan species are described from the feces of the ocellated woodcreeper, Xiphorhynchus ocellatus (Passeriformes: Dendrocolaptidae) collected in Ecuador. Isospora ocellatisp. n. sporulated oocysts are ovoidal, double-layered, 20×17 (18-21×15-19) pm with one polar body and no micropyle or residuum. The sporocysts are ovoidal, 12×8 (11-13×7-9) pm with dome-shaped Stieda bodies, compressed, bubble-shaped substieda bodies, and usually scattered residuum. Sporozoites are sausage-shaped with central nucleus and posterior refractile body. Isospora striata sp. n. oocysts are ovoidal, double-layered, 18x16 (16-20x15-17) pm with one polar body and no micropyle or residuum. The sporocysts are ovoidal 11×7 (11-12×7-8) Nm with nipple-shaped Stieda bodies, rectangular-shaped substieda bodies, and spherical, compact, residuum. Sporozoites are elongate, tapered anteriorly with large posterior refractile body, small central nucleus, and concentric rings around anterior half of body.

Tetrahymena vorax V_2S and Tetrahymena pyriformis GL were examined for the presence of proteins covalently modified with mevalonate-derived lipids. Radiolabeling of cells using [3H]mevalonolactone, [³H]mevalonate, [³H]farnesyl pyrophosphate or [³H]geranylgeranyl pyrophosphate resulted in the appearance of protein-associated radioactivity following protein delipidation in acetone. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of labeled protein revealed radioactive polypeptides ranging in molecular mass from 123 to 14 kDa following scintillation counting of gel slices or fluorography. Methyl iodide cleavage of total labeled protein followed by HPLC analysis and scintillation counting of the released prenyl alcohols showed radioactive peaks that co-chromatographed with commercially obtained farnesol (C₁₅) and geranylgeraniol (C₂₀).

Descriptions are provided of the morphology, infraciliature, life cycle, and ecology of the freshwater ciliate Prorodon viridis. P. viridis Prorodon viridis. P. viridis is a prostomatid ciliate with endosymbiotic Chlorellae and with a cosmopolitan distribution. The ciliate lives close to the oxic-anoxic boundary in freshwater lakes and ponds worldwide, and it is able to survive in anoxic, dimly-lit deep waters. The O₂-evolving endosymbionts - the zoochlorellae - probably sustain the aerobic respiration of the ciliate host. The vertical distribution of this species in natural oxygen gradients is described.

The nuclear apparatus of the Japan sea population of Tracheloraphis flexuosus RAIKOV et KOVALEVA 1968 consists of a longitudinal row of 20–30 macronuclei and 10–15 micronuclei usually arranged into groups of two macronuclei and one micronucleus in each. The nuclear groups lie in a voluminous perinuclear lacuna, the proximal membrane of which tightly applies to the nuclei leaving around them only a thin rim of ground cytoplasm. This membrane encircles each nuclear group separately and apparently holds the nuclei together. The micronuclei are filled with spongy condensed chromatin and limited by a conventional envelope with pores. The micronuclear chromatin is resistant to bleaching with BERNHARD's EDTA. Young macronuclei occur in some groups and contain small scattered chromocentres but no nucleoli; the chromocentres are readily bleached with EDT A. Adult macronuclei contain several nucleoli of usual structure (fibrillar core, granular cortex), several chromocentres and rarely a small sphere. The chromocentres are heterogenous: each one shows a dense cap. They become bleached with EDTA even after short exposure whereas nucleoli and the sphere retain contrast. The nuclei of Tracheloraphis flexuosus are smaller than those of T. dogieli, the similar European form.

We investigated a common, free living, marine, phagotrophic flagellate by light and electron microscopy. It has two heterodynamic flagella, a flexible cell shape and a pronounced apical rostrum. So far it was regarded as dinoflagellate and called Pronoctiluca phaeocysticola (Scherffel) Pavillard. Our investigation revealed, however, that it belongs to the bodonids (Kinetoplastida). The mitochondrium is of the polykinetoplastic type. The two flagella insert in a deep flagellar pocket and have a paraflagellar rod. The cytostome, the cytopharynx and the rostrum are supported by various cytoskeletal elements, the most prominent of which is a reinforced microtubular band. A distinct rod organ(= microtubular prism, nemadesm) has not been found. It has extrusomes of the “lattice tube” type. A distinct glycocalyx and a spiral groove of the cell body are absent. It fits the description of Hemistasia klebsii Griessmann. We regard both as con-specific and introduce the combination Hemistasia phaeocysticola (Scherffel) Elbrächter & Schnepf, comb. nov. The delimitation to other, similar organisms placed in various genera is discussed.

During an investigation of the silica-scaled chrysophytes in Tierra del Fuego, eighteen taxa were found, which had not previously been recorded from Argentina. These give a new insight in the biogeographical distribution of these algae. Three groups of species could be distinguished; one shows a pattern of latitudinal distribution in temperate areas of the Northern and Southern Hemisphere, the other has a general distribution in temperate, subtropical and tropical regions. The third group contains a few endemic species.