"Experiment 4" - Transformation

Goal: Measure transformation frequency of KW20 and Δhfq (RR3187).

Method:

1. Incubate two cell broths (one KW20 and one Δhfq) to an OD600 around 0.25
2. Filter cells from sBHI solution to MIV solution, grow for 100 minutes
3. Combine 1 mL cell solution with 1 microgram MAP7 DNA for 15 minutes
4. Dilute cells and plate dilutions
5. Count colonies the next day

Results:

Figure 1: Colony Count

• Notice that the cells plated on the non-antibiotic plate (red bars) are plated at a much more dilute concentration but have more colonies than most of the antibiotic plates did

Figure 2: cfu/mL

•  We can see the disparity between the two plates here. There appears to be a transformation frequency of about 10^-3 for KW20 and a frequency of roughly 10^-4 for Δhfq
• I personally don't know if this is a high frequency for Δhfq, I'll have to look it up

Figure 3: An averaged version of the previous graph

What I learned:

• How to do bar graphs with ggplot2
• How to make plates (all plates were the first I made; may have impacted results?)
• How to filter cells
• Use different volumes when plating a cells to have more countable plates and to calculate a more accurate cfu/mL value
• give Δhfq more time to grow (small colonies due to slow growth rate)
• Avoid labeling lids of plates. I accidentally swapped the lid for the 10^-4 plain and antibiotic plates. This gave me temporary confusion when comparing plates the next day.