Plating Tests
Negative Control (No Pressure)
Figure 1. Negative control was K1783002 (constitutive unstable RFP) grown in media without chloramphenicol. After 2-3 days, plates demonstrate fewer than 10 colonies per plate, suggesting that antibiotic resistance is now only minimally present in the culture.
Chloramphenicol Pressure Only
Figure 2. K1783002 (constitutive unstable RFP) grown in media with chloramphenicol. Colonies persist through several days of plating, suggesting that antibiotic resistance was maintained throughout the test.
Chloramphenicol + Hok-Sok Pressure
Figure 3. K1783003 (constitutive unstable RFP under Hok-Sok regulation) grown in media with chloramphenicol. Colonies persist through several days of plating, suggesting that antibiotic resistance was maintained throughout the test.
Hok-Sok Pressure Only
Figure 4. K1783003 (constitutive unstable RFP under Hok-Sok regulation) grown in media without chloramphenicol. Colonies persist through several days of plating, suggesting that antibiotic resistance was maintained throughout the test.
Growth Curve
Future Plans
Considerations
PCR of Hok-Sok Construct
Amplification of the Hok-Sok cassette is difficult due to the high inherent secondary structure in the construct. Hok ssDNA is capable of naturally folding into a stable secondary structure, resulting in early terminations and other side products. We recommend that a reaction buffer suitable for difficult templates be used, such as Phusion GC buffer + added DMSO.
Measuring OD of RFP Cultures
Due to the close proximity of the emission wavelength of RFP (584 nm) and the classical absorbance wavelength for measuring cell density (600 nm), it is difficult to accurately determine the cell density of cultures that are expressing RFP. Given more time to calibrate our testing measurements, we would either have used an alternative wavelength for measuring OD (>600 nm), used a hemocytometer as an alternate counting method, or switched to GFP as an alternative fluorescent marker whose emission wavelength differs from 600 nm by a greater amount.
Project Results
Here you can describe the results of your project and your future plans.
What should this page contain?
- Clearly and objectively describe the results of your work.
- Future plans for the project
- Considerations for replicating the experiments
Project Achievements
You can also include a list of bullet points (and links) of the successes and failures you have had over your summer. It is a quick reference page for the judges to see what you achieved during your summer.
- A list of linked bullet points of the successful results during your project
- A list of linked bullet points of the unsuccessful results during your project. This is about being scientifically honest. If you worked on an area for a long time with no success, tell us so we know where you put your effort.
Inspiration
See how other teams presented their results.
