Previous studies on adaptive behaviour in single-celled organisms have given hints to the origin of their memorizing capacity. Here we report evidence that a protozoan ciliate Tetrahymena has the capacity to learn the shape and size of its swimming space. Cells confined in a small water droplet for a short period were found to recapitulate circular swimming trajectories upon release. The diamet...

The ultrastructure of the surface epithelium and tubular glands of the uterus in the immature ostrich is described. In ostriches with inactive ovaries the uterus is lined by a non-ciliated simple columnar epithelium, with basally located heterochromatic nuclei. Scanning electron microscopy revealed that these non-ciliated cells have a dense microvillous cover. A simple columnar to pseudostratif...

The epididymis of the lizard Eutropis carinata can be divided into four regions viz., an initial segment (extra testicular) Efferent ductules (Eds) and three regions, anterior region, a broad middle, narrow posterior, comparable to caput, corpus, cauda epididymidis mammals. region is closely associated with whitish testicular), (Eds). epididymal wall consists epithelial layer lining lumen resti...

Cigarette smoke exposure is a major health hazard. Ciliated cells in the epithelium of the airway play a critical role in protection against the noxious effects of inhaled cigarette smoke. Ciliated cell numbers are reduced in smokers which weakens host defense and leads to disease. The mechanisms for the loss of ciliated cells are not well understood. The effects of whole cigarette smoke exposu...

Histological, histochemical and ultrastructural studies were performed on the epididymal regions of ten adult sexually mature apparently healthy male native turkeys (Meleagrisgallopavo). The epididymis of turkey was consisted of extra testicular rete, efferent ductules, connecting ductules, and the epididymal duct. The rete testis were lined by squamous to cuboidal cells, while the proximal eff...

Aerobic activated sludge granules are dense, spherical biofilms which can strongly improve purification efficiency and sludge settling in wastewater treatment processes. In this study, the structure and development of different granule types were analyzed. Biofilm samples originated from lab-scale sequencing batch reactors which were operated with malthouse, brewery, and artificial wastewater. ...

OBJECTIVE Mascara is a mild irritant that causes a range of medical problems. Animal models to predict ocular irritation have, however, been questioned at a number of levels, and there is a continued need to develop in vitro testing methods. METHODS We assess changes in an easily quantifiable attribute, ciliated protozoan growth rate, as a sensitive, sublethal measure. Specifically, we test s...

The ultrastructure of the somatic cortex of the ciliate Pseudomicrothorax dubius is studied with emphasis on the epiplasm layer which lies immediately under the inner alveolar membrane and is continuous with the terminal plates of cortical basal bodies. In addition to a clearly demonstrable cytoskeletal role, the epiplasm appears to function as a comenting substance which integrates numerous co...

We assessed the toxicity of ammonia ions to Stentor coeruleus and Coleps hirtus (Protozoa) isolated from activated sludge taken from two municipal wastewater treatment plants in southern Poland. Stentor coeruleus is a rarely occurring species in activated sludge, unlike the widespread Coleps hirtus. The mean LC50 values (concentration causing 50 % mortality) calculated for the 24 h tests differ...