3 October 2018 ✷ Enriching Soil 4

Rationale: Soil was enriched in order to isolate a phage.

Procedure

• The lab table was cleaned with CiDecon and 70% ethanol and an alcohol lamp was lit to promote an aseptic environment.
• 2 mL of soil was added to a tube and 10 mL of LB broth was added and the vial was vortexed for 15 minutes. It was then centrifuged for 10 min at 10,000 g.
• A small amount of soil was placed in a pH vial and DI water was added; the vial was shaken for 30 seconds and a pH test strip was inserted for 45 seconds and then read immediately.
• The centrifuged sample was removed with a syringe and filtered through a 22 micron syringe filter into 2 vials: one for a “direct” lysate and one for an “enriched” sample. 0.5 mL of arthrobacter was added to the “enriched” sample and stored in a shaking incubator until Monday. The direct sample was refrigerated.

observations, results, data

pH: 5.5  

% sand, silt, clay

total: 6 mL

clay: 0.5 mL = 8.3%

silt: 5 mL = 83.4 %

sand: 0.5 mL = 8.3%

interpretations, conclusions, next steps

The silt percentage is higher in sample 4 than in other soil samples collected by group 6. Perhaps this will result in the discovery of a phage since it is a new and unique quality to the collected soil samples.

In the next lab period, a spot test will be conducted in order to test for the presence of a phage.