Brown: Team Resistance/16 July 2008

16 July 2008

Kate and Neil began the PCR while I was in class

Made a 1/100 dilution of pVJ4

Once culture reached OD of 0.018,I began concentrating the culture for testing Concentrated 10mL of culture 7x (used all the culture we had); 5mL +arabinose, 5mL control Final OD of concentrated solution: 0.289 of mid-log culture

Will have to run the test experiment and the control experiment in succession since our system currently can only measure one plate at a time

Began testing: 1:35pm Comparison resistor: 4.652kΩ Amplification: 1000 V(output): 0.2V

At 3:30pm → no change in resistance The culture also did not get clear, like we usually see when cells lyse However, because solution is concentrated, DNA and proteins are going to prevent the solution from getting clear

Decided to let the test run overnight to see if any change occurs

Tomorrow:

• Try using 10mL unconcentrated culture resuspended in water (possibly easier to detect a change if we start in something with 0 ions of its own)
• Make sure cells begin in mid-log phase (OD: 0.05 vs. 0.018)
• Run gel of PCR product

Possible reason of why it doesn’t work with a concentrated solution is because the DNA and proteins seem to be scaffolding onto the electrodes and interfering with resistance readings