Mackenzie Singer

Lab 7

10/4/18

Objectives:

The purpose of this lab is to use the assays we practiced in lab last week to observe the treatment of twice juice on tetrahymena. We also were able to become comfortable using the serological pipette to get samples of culture. The purpose of the experiment is to see if the microplastics in the hay baling twine effect organisms in the ground. If the organisms are harmed, it will prove that the microplastics are harmful to the environment on the microscopic and macroscopic levels.

Procedure:

Prior to this lab, Dr. Adair and the TAs prepared and observed the growing tetrahymena twine juice solution.

Cell Count:

1. Obtain a flask of 50 mL brown twice juice solution.
2. Aseptically transfer 40 mL of treatment and control into separate sterile test tubes. Keep tubes in a test tube rack.
3. Observe the two solutions with a spectrophotometer and record the results in a lab notebook.
4. Use a micropipette to transfer three 2 µl drops onto a clean slide and then add 1 µl of iodine to each drop.
5. Observe the drops and count the number of cells in each and record in lab notebook.

Swim Speed Assay:

1. Place a 20 µl drop of tetrahymena twine juice solution on a clean flat slide.
2. Set a metric ruler in the field of view on the microscope at 4x. Adjust the slide so that you can see the cells over marks on the ruler.
3. Choose one cell to watch and line it up with the inside of a mark.
4. Start a stop watch when a cell hits the mark and stop the time when it reaches a distance of 10 marks away. Only cells swimming straight should be included.
5. Record 10 cells.
6. Repeat with a 20 µl drop of control solution on a separate slide. Record in lab notebook.
7. Swim speed can be expressed as mm/s.

Data:

Absorbance:

Cell Count:

Swim Speed Assay:

Control

Treatment

Storage:

The microscopes were covered and placed on lab tables. Slides were washed off and laid out to dry. The test tubes containing control and treatment solution were covered and placed on the back table for use during open lab.

Conclusion:

We used the twine juice and behavioral assays in order to test the effect of microplastics on tetrahymena. We were also able to practice experimental design with the pre-lab which is essential for bio research. We also practiced using serological pipettes, which will be important for future labs. Future steps of these assay experiments will be used when we evaluate the microplastics in soil in our own experiments.