Date of Experiment: September 13, 2018

Objectives:

• Identify Tetrahymena
• Learn how to properly use a micropipette

Purpose: To identify Tetrahymena and its characteristics and how these will be affected in future experiments where microplastic pollution is introduced to the environment.

Background Information on Tetrahymena:

• Contributed to the discovery of telomerase and ribozyme
• Displayed histone acetylation, a form of gene regulation
• Can undergo asexual reproduction, but will engage in sexual reproduction under extreme environmental pressures
• Common in freshwater
• Possesses two types of cell nuclei: non-germaline macronucleus and germaline micronucleus

Materials:

• Micropipette
• Concavity Slide
• Dissecting Microscope
• Well Plate
• Ruler
• Calculator

Procedure:

1. Calculate the field of view, using a ruler to measure the diameter of the field of view in millimeter, converting these measurements to micrometers.
2. Using a micropipette, collect 5 microliters of Tetrahymena from its well plate and place the solution on a concavity slide.
3. Observe the ciliate under 4x and 10x magnification.
4. Estimate the number of cells observed under each magnification.
5. Repeat steps 1-4 for three overall trials

Observations:

Field of view diameter: 3 mm

Trial	Magnification	Number of cells in 5 uL	Diameter (um)	Drawing
1	4x	300	12000 um
	10x	20	1200 um
2	4x	200	12000 um
	10x	20	1200 um
3	4x	300	12000 m
	10x	45	1200 um

Results:

As a result of the time constraint of the experiment, I may have either widely underestimated or overestimated the amount of cells in the culture as I hastily observed the cells in an attempt to complete the experiment in the allotted time. In doing so, the the number of cells recorded may be far from an accurate approximation of the cell count.

Conclusions/Next Steps:

Improvements to be made in future experiments would be to thoroughly observe the amount of cells in the culture to receive an better representation of the actual cell count. Despite the inaccurate cell count received duing the experiment, I was able to discern that Tetrahymena continues to thrive at a much higher rate than that of other ciliates observed in past experiments.  With these results, I will experiment on the ability of Tetrahymena to flourish and the number of Tertahymena cells to be affected in response to introducing microplastic, a toxin, to the culture.