Formation and degradation of large extrusion bodies in Tetrahymena thermophila: The role of intramacronuclear microtubules in chromatin segregation.

Large extrusion bodies (EBs) in Tetrahymena thermophila were induced by treatment with aphidiocolin (APH), followed by transfer of the cells to a drug free medium. APH induces over-replication of DNA and reversible cell division arrest (Kaczanowski and Kiersnowska, 2011). After treatment the cells were transferred to a drug free medium, and a central granule of chromatin (a prospective EB) surrounded by microtubules developed inside the macronucleus.

Cell cycle-dependent modulations of fenestrin expression in Tetrahymena pyriformis.

In Tetrahymena, besides apparent cell polarity generated by specialized cortical structures, several proteins display a specific asymmetric distribution suggesting their involvement in the generation and the maintenance of cell polarization. One of these proteins, a membrane skeleton protein called fenestrin, forms an antero-posterior gradient, and is accepted as a marker of cell polarity during different cellular processes, such as cell division or oral replacement. In conjugating cells, fenestrin forms an intracytoplasmic net which participates in pronuclear exchange.

Inactivation of a macronuclear intra-S-phase checkpoint in Tetrahymena thermophila with caffeine affects the integrity of the micronuclear genome.

Aphidicolin (APH), an inhibitor of DNA polymerase α, arrested cell divisions in Tetrahymena thermophila. Surprisingly, low concentrations of APH induced an increase of macronuclear DNA content and cell size in non-dividing cells. In spite of the cell size increase, most proliferation of basal bodies, ciliogenesis and development of new oral primordia were prevented by the APH treatment.

Triterpenoid saponins affect the function of P-glycoprotein and reduce the survival of the free-living stages of Heligmosomoides bakeri.

We studied the effect of triterpenoid saponins on the development of free-living stages of Heligmosomoides bakeri, a parasitic nematode of the mouse intestine. We evaluated the effectiveness of oleane-type glucuronides (GlcUAOA) isolated from Calendula officinalis and Beta vulgaris. The rhodamine 123 retention assay was used to detect dysfunctions of the major membrane transporter for xenobiotics, P-glycoprotein (Pgp).

Acquisition of cell polarity during cell cycle and oral replacement in Tetrahymena.

The aim of this study was to search for a mechanism responsible for the acquisition of cell polarity in a ciliate Tetrahymena. Homologs of the mammalian genes coding for CDC42-GSK3beta- MARK/PAR1-MAPs proteins were found in the Tetrahymena genome (Eisen et al., 2006, and this study).