The effects of toluene on the ciliary function of Tetrahymena thermophila

  • Harry Chun Man Cheng
  • Nazde Edeer
  • Navpreet Ganda
  • Erik Johnson


Tetrahymena thermophila is a ciliated protist and a well-studied organism that is used as an experimental analogue for ciliary function in other eukaryotes. We studied it as a model for human endotracheal ciliary response to toluene, a compound found in both cigarettes and e-cigarettes. We performed three experiments with four replicates each: a motility assay to study the effects of toluene on movement, a food vacuole assay measuring the ability of T. thermophila to phagocytose Congo-red stained yeast using their oral cilia and a cell viability assay in order to determine whether cells without food vacuoles were still alive. We found significant differences in the percentage of moving cells in the first assay as we increased the concentration of toluene, as well as significant and similar differences regarding food vacuole formation in our second assay. Our last assay found no significant difference in the amount of viable cells without food vacuoles at each of three concentrations tested. Taken together, these data suggest that short-term exposure to toluene does not kill T. thermophila, but may inhibit ciliary function. The mechanism by which toluene acts on cilia is unknown, however previous studies have suggested that the toxicity of toluene is associated with its methyl side chain, as it can form hydrogen bonds with other molecules.