Rationale: As a group we wanted to devise a testing question we all agreed on and then collect soil to investigate our question.

The class decided to have different tables focus on different questions.

My table decided on the question “In the Texana area of the Baylor campus, is there a correlation between tree species and arthrobacter presence?”

We chose this question because there is possible fire damage in the Texana area which could indicate arthrobacters.

In addition, we found a list of tree species so it will be relatively easy to compare red and white oaks – white oaks supposedly have a higher risk of infection (arthrobacters?)

My new lab group of Lily and Soo went to the Rogers building and collected soil from a red oak tree nearby.

• we saved ~4 mL of soil in a 15 mL tube each
• we also had bags filled with a leaf from the tree and extra soil
• we left the bags to be refrigerated

Plan for next class: wash the soil and make a direct isolation and enriched isolation

Lab goal: spot direct and enriched samples on an LB plate to test for plaques

Process:

1. Made LB top agar
   1. Decided to make 4 plates worth of agar media in one 50 mL tube so we started by putting 18 mL of LB broth into the 50 mL tube
   2. After this step we decided to separate our control media so we moved 4.5 mL of the LB broth into a new 50 mL tube
   3. The table below shows the amounts of reagents added to the two tubes
   4. 
      

      Reagent	Control Tube	Plate Agar
      Artho	NA	1.5 mL
      LB Broth	4.5 mL	13.5 mL
      2x TA	5.0 mL	15 mL
      1M CaCl2	45 µL	135 µL

2. Used a pipette to put 10 mL of agar into a plate for each group member (Rachel, Lauren, and Lily)
3. Poured all of the control tube into the control plate
4. We let the plates sit for about 10 minutes
5. Using a sterile syringe and a syringe filter, filter about 2 mL of the enriched isolated sample into a microcentrifuge tube
6. Used a micropipette to spot plate with 4.4 µL of:
   1. Filtered enriched isolated sample
   2. Direct isolated sample
   3. Phage Buffer (negative control)
7. Started incubating the plates (not inverted) at 4:14 PM

Lab goal: wash soil samples collected from section 8 and produce a direct isolated sample and an enriched isolated sample.

Process:

1. Cleaned lab bench with CiDecon and 70% ethanol
2. Using aseptic techniques, added LB broth to the 35 mL mark of the 50 mL tube containing approximately 15 mL of soil
3. shook and vortexed the tube for 15 minutes
4. Added about 1/2 mL of water to get a final weight of 46.59g
5. Centrifuged the tube with the rest of the class
6. Used a bulb pipette to transfer supernatant from the centrifuged tube to a filter
7. After filtering, poured about 3.5 mL of the filtered product into a 15 mL tube leaving about 8 mL in the 50 mL tube
8. Added 0.5 mL of artho to the 50 mL tube
9. Labeled the 15 mL tube as direct isolated sample and stored it in the fridge
10. Labeled the 50 mL as enriched isolated sample and left it in the shaking incubator