14 November 2018 ✷ Plaque Assay

Rationale: Members of group 6 adopted phage from Soil 4 from Melissa (collected 10/5/18) in order to help amplify the phage sample. A plaque assay was run with the newly enriched portion of her sample in order to confirm the presence of a phage.

Procedure

• The table was cleaned with Cidecon and 70% ethanol and an ethanol lamp was lit.
• 30 µL of filtered enriched lysate was added to 0.5 mL of arthrobacter and allowed to infect for 15 minutes before being combined with the plate mix for a plaque assay.
• A plate for a 2 plaque assays and a control plate were made with the following concentrations and volumes:

• component	volume	final concentration
  LB Broth	6 mL	–
  2X Top Agar	7.5 mL	1X
  1M Calcium Chloride	68 µL	4.5 µM

• The arthro/lysate mix was combined with 5 mL of the above plate mix and the plate was poured, allowed to harden, and then inverted and incubated until Monday at 27 degrees celsius.

Observations, results, data

The soil sample used for this plaque assay was positive when Melissa tested it, so the plaque assay should be positive when it is examined on Monday in lab.

Interpretations, conclusion, next steps

The plaque assay will likely be positive because the soil sample produced a positive plaque assay in the past. This being said, a plaque will be picked from the plaque assay and then re-run to try and isolate a phage and amplify its DNA.