Growth Curve and Cell Count

Cell count via Hemocytonomer

1. Clean the cover glass mounting support and the coverslip of the hemocytometer with a lens paper and some ethanol.
   Note: Coverslips for counting chambers are specially made and are thicker than those for conventional microscopy, since they must be heavy enough to overcome the surface tension of a drop of liquid.

2. Place the coverslip over the counting surface prior to putting on the cell suspension.

3. Introduce the suspension into one of the V-shaped wells with a pasteur or other type of pipet.
   Note: The area under the coverslip fills by capillary action. Enough liquid should be introduced so that the mirrored surface is just covered.

4. Place the counting chamber on the microscope stage and bring the counting grid is into focus at low power.

Growth Curve

1. With the use of a hemocytometer, count the number of cells present in a small sample of your culture

2. With this number, calculate the cell density (cells/ml) of your culture

3. For the same culture, take cell count measurements on a regular basis (every 5 hours) for an entire week

4. Record all the data you collect and the time at which you took the measurement!

5. Once the week is over, plot cell density versus time in order to obtain a growth curve

6. You must be able to see the different growth phases the species goes through (log, stationary)

Antibiotic Spot Test