Identification of a multidrug resistance‐like system in Tetrahymena pyriformis: evidence for a new detoxication mechanism in freshwater ciliates

Abstract

The freshwater ciliate Tetrahymena pyriformis is an ubiquitous organism that is present in all aquatic ecosystems. This protozoan showed a clear resistance against some polycyclic aromatic hydrocarbons which can be attributed to an efflux pump probably of the multidrug resistance (MDR) type. Immunocytochemical detection showed a positive stain of ciliate cells using the monoclonal antibodies 4E3, raised against P-glycoprotein (P-gp). The kinetics of P-gp expression were studied for control cultures and cultures treated with 15 W WM benzo(a)pyrene. Western blot analysis using the Ab1, anti-P-gp polyclonal antibodies indicates the presence of two bands of 66 and 96 kDa of which the intensity increased with time in benzo(a)pyrene-treated ciliates. Uptake experiments with target compounds for the MDR pump, namely adriamycin, rhodamine 123 and two polycyclic aromatic hydrocarbons, benzo(a)pyrene and 7,12-dimethylbenzanthracene, were carried out by flow cytometry, in the presence or absence of cyclosporin (an inhibitor of the multidrug resistant pump). The data indicate that the accumulation of these compounds by ciliate cells is significantly enhanced in the presence of cyclosporin. This suggests that Tetrahymena is provided with a P-gp-like system that is functionally active in a way similar to that of the mammalian P-gp.z 1999 Federation of European Biochemical Societies.

A circadian clock regulates sensitivity to cadmium in Paramecium tetraurelia

“…It is known that p-glycoprotein is involved in cadmium resistance in some invertebrates in which the molecule acts to pump cadmium out of the cell (Broeks et al 1996;Callaghan and Denny 2002). This protein has been shown to contribute to cadmium resistance in E. gracilis (Einicker-Lamas et al 2003) and is reported to be present in the ciliated protozoan Tetrahymena thermophila (Bamdad et al 1999). Furthermore, the gene has been identified in P. tetraurelia (Hinrichsen, unpublished data).…”

Effects of triclosan and triclocarban on the growth inhibition, cell viability, genotoxicity and multixenobiotic resistance responses of Tetrahymena thermophila

“…Tetrahymena represent an ecologically relevant animal group and a valuable model frequently used for assessing toxicity of contaminants. The MXR system in Tetrahymena was firstly demonstrated by Bamdad et al (1997Bamdad et al ( , 1999. So far, a total of 165 ABC transporter genes in the T. thermophila macronuclear genome were identified.…”

A review of selected anti-tumour therapeutic agents and reasons for multidrug resistance occurrence

“…Ciclosporin is used in lower concentrations than other chemosensitizers ($0.5-3 M) (Ford 1996;Ruiz et al 2000). Bamdad et al (1999) have suggested that the accumulation of adriamycin, rhodamine-123, benzo(a)pyrene and 7,12-dimetylobenzoanthracene in ciliate cells, Tetrahymena pyriformis, is significantly enhanced in the presence of ciclosporin. Larrive´e & Averill (1999) have proved that ciclosporin can increase the intracellular accumulation of melphalan in Chinese hamster ovary cells.…”