Domenica DiStasio Tetrahymena Lab Report Introduction: In this lab we experimented on a unicellular organism known as Tetrahymena thermophile. We evaluated the effects that various drugs or conditions would do to the eating habits of the organism. We choose to specifically focus on the effects that Calcium has on food consumption. We hypothesized that if Tetrahymena consume food through phagocytosis, then if we block the process of phagocytosis in the organism, no food will be consumed (no food vacuoles will be present in the cell). Calcium is an inhibitor of phagocytosis so if we are able to add the Calcium to the Tetrahymena then we should be able to stop phagocytosis and the Tetrahymena should not be able to eat the India Ink. In figure 3 of the Calcium paper, it shows that when Tetrahymena are in solution of Calcium, they do not grow food vacuoles because the Calcium inhibits it (Claudia E. Moya et al., 2006). To achieve these same results that were in figure 3, we first fed the Tetrahymena with India Ink without adding any Calcium. In the second part of the experiment we fed the Tetrahymena the India Ink and then added 2 microliters of a 40 millimolar Calcium solution. We took samples of the solutions at zero and ten minutes and put the samples into glutaraldehyde to kill the organism so they wouldn’t eat any more of the ink and so we would get accurate readings. We then looked at the samples under a microscope and recorded the number of food vacuoles that were present. If my hypothesis is supported, then the Tetrahymena that have the Calcium in them will not undergo phagocytosis and will therefore not eat the India Ink and not grow food vacuoles. If my hypothesis is not supported, then the Tetrahymena will still undergo phagocytosis and food vacuoles will be present in the cells. Results: Our results showed that the Calcium definitely does inhibit phagocytosis in the Tetrahymena cells (Figure 1). It also proves that Tetrahymena do eat through phagocytosis. After ten minutes, the Teatrahymena that had Calcium in them had only grown on average, .1 food vacuoles, versus the cells that were not in a Calcium solution, which had grown on average 9.5 food vacuoles (Table 1 and 2). The Tetrahymena that ate the India Ink and did not have calcium in them grew food vacuoles at an average of 9.5 vacuoles after 10 minutes (Table 1). When Tetrahymena are in a solution of calcium food vacuoles do not grow because the calcium inhibits phagocytosis. These results were recorded by counting the number of food vacuoles in 4 Tetrahymena cells under a microscope. These results were then recorded in a table and analyzed by finding the mean and standard deviation of the specific data sets.TABLE 1 Test Tube 3: Tetrahymena not in a calcium solution (control group)Time Cells 1 2 3 4 Mean Standard Deviation0 1 2 1 5 2.25 1.8910 10 8 12 8 9.5 1.91TABLE 2 Test Tube 4: Tetrahymena in calcium solution (experimental group)Time Cells 1 2 3 4 Mean Standard Deviation0 0 0 0 0 0 0.0010 0 1 0 0 0.1 0.500 2 4 6 8 10 12012345678910Food Vacoule Growth of Tetrahymena In Calcium Solution or Neutal Bufferno calcium calciumTime (minutes)Number of VesiclesFigure 1: Average number of food vacuoles in Tetrahymena in calcium solution or neutral solution over a ten-minute time period.References: Moya CE, Jacobs RS. Pseudopterosin A inhibits phagocytosis and alters intracellular calcium turnover in a pertussis toxin sensitive site in Tetrahymena thermophila. Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology.