Imperial College London/Notebook/2 October 2009

Testing team update

Harvard-GFP

• There is a difference in fluorescence between 28°C and 37°C after compensating for OD.
• Need to adjust the gain so that fluorescence doesn't saturate
• 23rd September
• 30th September

OD calibration

• Preliminary results show that cell number varies with OD. However, the right dilution and enough replicates to overcome the huge variation are required.
• 17th of September (up)
• 23rd of September (awaiting results)
• 25th of September
• 2nd October (awaiting results)

Secondary carbon sources

• There appears to be a plateau in cell number after 6 hours with 0.05% Glucose. However, more data is required to determine if this is the switch point.
• 8th September (up)
• 10th September (up)
• 1st October

GFP pH

• 18September (awaiting data analysis)

IPTG growth

• IPTG with its dual effects of possible toxicity and protein production stress, has no effect on cell growth under the concentrations tested (100uM to 5mM)

Testing

OD calibration 4th run 2nd Oct

Protocol considerations

• Cells were grown overnight in 10ml of M9 media
• The cells were allowed to grow until a high OD in the late morning, then placed in cold room
• OD of around 0.4 to 1.2 was made up, and subsequently diluted up to 10^-4 to 10^-6
• 100ul of cells were inoculated into each plate
• The OD of the overnight cells were measured again after 3 hours on ice to check if cell number changes during dilution process

Results

Waiting to be uploaded

Conclusions

• After 3 hours on ice, the OD stays relatively constant
  • Shows that number of cells during OD measurement and during plating stay the same. Therefore, OD correlates with the number of cells that are plated.

Suggestions/Improvements

Waiting to be uploaded