The effect of time and food concentration on vacuole formation in <i>Tetrahymena thermophila</i>


  • Genevieve Carpenter-Boesch
  • Stephanie Schaupmeyer
  • Andrew Tulloch
  • Dustin Woo


The objective of this experiment was to study how time in food and food concentration affects food vacuole (FV) formation in Tetrahymena thermophila. This experiment gives us insight into the process of phagocytosis, a crucial biological process for T. thermophila to uptake nutrients. We diluted SSP medium containing Congo red (CR)-stained Saccharomyces cerevisiae (yeast) into concentrations of 8 × 107, 4 × 107, and 2 × 107 cells/mL added them to T. thermophila cultures, and allowed feeding for 60 minutes. samples were taken at 1, 15, 30 and 60 minutes. T. thermophila were then examined under the microscope to count the number of CR-stained FVs that were formed. After conducting a two-way ANOVA to analyze our data, we determined that the concentration of food available to T. thermophila in the medium had no significant effect on the number of FVs formed, but the length of feeding time was statistically significant. It was also found that these two independent variables were not interacting. T. thermophila is biologically limited in how quickly phagocytosis can be performed by the maximum capacity of its oral groove, which can explain the significant effect of time on FV formation.