Noon measurement

We measure the cultures again after ~4 hours. This is to be more certain whether the cultures were in fact in stationary phase in the 08:00 am measurement.

The below video demonstrates the sample workup. It is the exactly the same as in the morning measurement.

1

Retrieve a sample

Use a serological pipette to sample 1 mL culture. Transfer to a 5 mL centrifuge tube. Note down the sampling time.

2

Disaggregate cell clumps

Vortex the vial 1 minute at maximum speed to disaggregate cell clumps. See Break up clumps and chains if your bacterium needs more aggressive disaggregation than this.

3

Dilute 1:100

Transfer 101 µL of your sample to 10 mL of diluent. Vortex 10 seconds at maximum speed.

4

Dilute 1:10 000

Transfer 101 µL of the diluted sample to 10 mL of diluent. Vortex 10 seconds at maximum speed.

5

Measure the diluted sample on BactoBox®

Transfer the tubing kit to the 1:10 000 vial.

Press Measure in Access to start a new measurement.

• Dilution: 10 000

• Label: Growth_medium_type . For example LB or TSB.

After completing the measurement, Access will automatically calculate the cell concentration in the culture in the cellsCells/mL × Dil.

6

Check remaining cultures

Repeat above steps with 1:10 000 dilutions of the remaining growth media.

Summary

You have now determined the cell concentration for the morning measurement. Wait ~4 hours before proceeding to Afternoon measurement.