Rationale: After contamination, the purpose of this lab is to sterilize the flooded lysate and to perform a plaque assay.

Description of Procedures:

1. The workstation was cleaned using aseptic technique and an ethanol burner was lit to create an aseptic zone.
2. Top agar solution was made for two plates. 4 ml of LB Broth and 45 ul of CaCl2 were added to a tube.
3. 50 ul of chloroform were added to the flooded lysate to kill any bacterial contamination. The lysate was swirled for 2 minutes.
4. 10 ul of lysate was added to 0.5 ml of arthrobacter and allowed to sit for 10 minutes.
5. 5 ml of 2x TA were added to the top agar solution and pipetted up and down to mix. 4.5 ml of the top agar solution were added to the arthrobacter and poured onto a plate labeled LIP 10-22-18 PA. The rest was poured directly onto a plate labeled LIP 10-22-18 Control.
6. The plates were allowed to settle for 10 minutes and then inverted and stored in the incubator until the next lab.
7. The workstation was cleaned using aseptic technique and materials were properly stored or disposed of.

Observations:

• Chloroform was used instead of a syringe filter to sterilize the lysate.
• No bubbles were seen on plates.

Interpretations/Next Steps:
The procedure was complete. The next step will be to check for plaques. If plaques are found, serial dilutions will be performed. If no plaques are found, a new plaque will need to be picked for purification.

Contaminated Plaque Assay and Control: