If the original concentration of a phage was markedly increased from the concentration that you received, how could you ensure that you had between 30-300 plaques on your plate? (instead of TNTC)
If the original concentration of a phage was markedly increased from the concentration that you received, how could you ensure that you had between 30-300 plaques on your plate? (instead of TNTC)
Related textbook solutions
Related questions
A friend of yours is doing a critical experiement with E. coliand needs your help to enumerate the sample. One ml of the cultureis mixed with 9 ml of saline, which is then further diluteddecimally (1/10) 5 times and 0.1 ml of the last three dilutions arespread onto plates of MacConkey agar and PCA triplicate. Afterincuation you observe the following number of colonies
| Dilution in tube | 10-4 | 10-5 | 10-6 |
| PCA | TNTC TNTC TNTC | 251 232 246 | 21 28 25 |
| MAC | TNTC TNTC TNTC | 239 223 258 | 23 29 30 |
a) Determine the number of CFU/ml of the undiluted culture fromMAC plate counts.
b) Determine the CFU/ml of undiluted culture from the PCA platecounts.
C. MAC is a selective medium. Why are the nunbers of coloniesthat grow on the MAC and PCA plates nearly the same? If yourepeated the experiment with B. cereus instead of E. coli, wouldyou expect the number of colonies that grow on MAC and PCA platesto be the same? Explain.
