DNA content of Tetrahymena pyriformis as a biomarker for different toxic agents.

The toxicity of different substances was studied on the protozoan Tetrahymena pyriformis, using as an endpoint the DNA content of the macronucleus. Substances from various chemical classes were administered to the Tetrahymena cultures and then the DNA content of the protozoan macronuclei was measured by means of Image Analysis System. The increase in the DNA content of the nuclei is indicative of the stimulation of the mitotic process. Since mitogenic stimuli can substantially alter susceptibility to chemical carcinogenesis, the results of such experiments, which are cheap and easy to run, may contribute to the investigation of the toxic action of several substances on cellular level.