Title: Plaque Assay for Original Plaque (Redo)

Date: 26 September 2018

Rationale: Due to an error with the Arthrobacter culture, the previous experiment’s results are rendered invalid. The bacteria used was not Arthrobacter, therefore an Arthrobacterphage couldn’t grow on a bacterial lawn. Therefore the experiment is repeated. The attached pictures show the previous (contaminated/invalid) plaque assays.

Procedure: Aseptic zone created by washing the lab bench with CiDecon and ethanol and a heat lamp was lit.

• The picked 10^0 lysate from the previous experiment was used for 2 more 10^0 plaque assays.

The following recipe was used to make 8 plaque assays (7 PA + 1 Top Agar Control):

• 18.9 mL LB Broth
• 180 microliters CaCl2
• 20 mL 2x TA

~ 4.6 mL pipetted into a vial containing 0.4 mL new Arthrobacter strain + 10 microliters 10^0 lysate. The mixture was plated, cooled for 10-15 minutes, and incubated. \

Conclusions: Much like the previous experiment, both plaque assays must pass in order to continue passaging. If the test fails, soil will be recollected and the washing/purification process will start over.