Rationale

A plaque assay will be conducted and data from the sand/silt/clay metadata experiment will be analyzed.

Procedure

1. Use the aseptic technique to clean the area.
2. While working near a flame, 10 µL of filtered enriched lysate was added to a tube containing 0.5 mL of Arthrobacter. The tube was set aside for 10 minutes.
3. 8 mLs of LB broth was placed into a vial along with 90 µL of CaCl2 and 10 mL of 2X TA.
4. 4.5 mL of the contents in vial was pipetted into the vial containing the filtered enriched lysate and then was quickly poured onto a petri dish. It sat for 10 minutes.
5. When the plate was sitting, the percent sand, silt, and clay in the soil was analyzed.
6. After the plate sat for 10 minutes, it was inverted and placed in the incubator.

Observations

Air bubbles did occur during the plaque assay but they were minimal and occurred near the edges. There were also multiple layers of sand, silt, and clay as shown below and the different types were grouped together for analyzation purposes.

Total amount of soil: 10 mL

Total amount of sand: 8.25 mL

Total amount of silt: 1.25 mL

Total amount of clay: 0.5 mL

% Sand: 82.5%

% Silt: 12.5%

% Clay: 5%

Conclusion

The previous spot test conducted produced no plaques, therefore a plaque assay was conducted. The results of the assay will be observed on Wednesday, hopefully with the presence of plaques. If no plaques are produced, more soil will be collected and the process will start again

Additional Questions

1. The tree that Justin got his soil from may have a slightly different bacteriophage than the trees that Michael and Cooper used, which led to the difference in plaque presence.

(14 pfu/10 µL) x (1000 µL/1 mL)=1400 mL

1400 mLx10^3=1400000

(37.5^2)π/(0.5^2)π=5625

5625/1400000=0.004017 mL

0.004017×1000=4.01 µL