12 November 2018 ✷ re-enriching Soil 4

Rationale: Members of group 6 adopted phage from Soil 4 from Melissa (collected 10/5/18) in order to help amplify the phage sample. However, the plaques were lost in the last plaque assay, so the soil was re-enriched to isolate the phage again.

Procedure

• The table was cleaned with Cidecon and 70% ethanol and an ethanol lamp was lit.
• 5 mL of Soil 4 from Melissa’s collection on 10/5/18 was added to a conical vial and filled with 5 mL of LB broth and vortexed for 15 minutes.
• The sample was then spun at 3000 g for 10 minutes and the supernatant was removed via syringe.
• The supernatant was then filtered with a 22 micron syringe filter and 0.5 mL of arthrobacter was added to the vial. The sample was then incubated in a shaking incubator until Wednesday.

Observations, results, data

There were a few spots on the plate that may have been plaques, but the size and number is far less than the plate in which the plaques were picked from, so the experiment was repeated.

Interpretations, Conclusions, Next Steps

The soil sample used provided a positive plaque assay when Melissa carried out the experiment, but not when members of Group 6 tried, it was inconclusive. So, this is either the result of human error or other factors, such as the phage only existing in some parts of the soil and not others.

In the following lab periods, the lysate will be run through a plaque assay to identify the presence of a phage and later amplify it.