Observing chemotaxis in T. thermophila in the presence of glucose, lactose, and fructose


  • Irene Choi
  • Shaun Donnelly
  • Jeff Kim
  • Matthew Lim


Tetrahymena thermophila is a free-living, unicellular eukaryote that belongs to the ciliated Protozoa, a major, ecologically successful monophyletic group (Oraisis, 2011). T. thermophila is lined by many cilia and uses them to move through water, as well as to sweep bacteria and other small debris into its mouth (Bozzone, 2000). Chemotaxis is a phenomenon when cell movement is directed by an extracellular chemical gradient. During this chemosensory behaviour, cells can change their locomotion as they detect changes in the concentration of the chemical. Cells can be attracted as positive chemotaxis or repelled as a negative chemotaxis by various chemical signals. Cell migration is essential for both multicellular and unicellular organisms. Chemotaxis is especially important for T. thermophila since it impacts the survival of T. thermophila in various environmental conditions. In order to observe the impact of each sugar on T. thermophila, the following experiment involved culturing T. thermophila in one of glucose, lactose, and fructose for 15 minute after starvation phase. The research conducted in this project can help identify an optimal concentration range of examined sugar at which a strong positive attraction can occur. The experimental findings were that there was no significance for all three sugar treatments. This finding contradicts the initial hypothesis and implies that the study needs a greater sample size in order to investigate an overall effect on different sugar treatments.