Imperial College London/Notebook/17 September 2009

Testing

OD calibration 17th Sep

Protocol considerations

• Cells were grown overnight in 10ml of M9 media
• The cells were allowed to grow until a high OD (very cloudy) and retrieved in the early afternoon
• The OD was measured using the multiplate reader.
• As the OD was only around 1.5, the cells were centrifuged and resuspended in less media to form an OD of 3
• OD of around 0.5 to 3.0 was made up, and subsequently diluted up to 10^-6 to 10^-8
• Plated on strep plates and dried until the end of the day
• Placed into 37 degrees incubator (non-shaking) overnight

Results

The plates had too many colonies to count.

Conclusions

• The plates were all too confluent, even at 10^-8 dilution.
• Unable to count colonies and draw any colonies
• Need to repeat experiment

Suggestions/Improvements

• Was not done on ice, so cell growth still occurred during dilutions
• Too many colonies to count when plated 100uL
  • Use ice
  • Increase dilutions