Rationale: Conducting a plaque assay to see if the soil sample I collected has a phage in it. Then we can move on to the next steps of purification.

Procedure:

1. Pipetted 10μL of lysate into 0.5mL of arthrobacter. Then waited for 10

   minutes before beginning to make top agar.

2. Using aseptic technique and fresh pipettes each time put 10mL of LB broth

   in a 50mL tube, then 112.5μL of CaCl2, then 12mL of 2X TA.

3. Pipetted 4.5mL into tube with arthrobacter and lysate and pipetted up and

   down to mix.

4. Poured contents into plate while keeping the top as close to the bottom as

   possible as to not have any contaminants fall in.

5. Waited 10 minutes to solidify then inverted and incubated for 48 hours.

Observations:
The positive control ran by Lathan turned out negative meaning that the arthrobacter supply was contaminated. However, our negative control plate still turned out contaminated.

Interpretations and Next Steps:
There must be some other source of contamination for the control sample as it looks the same as the last plate which was contaminated. We need to find the cause of this because it will throw off our results every single time. (After looking back from 9/26 lab the cause of contamination was the contaminant in the TA.) Now we have to make another plaque assay next class since the arthrobacter we used wasn’t actually arthrobacter since it was contaminated by another bacteria.