TABLE 3.
Influence of plate conditions on precision plating
| Growth conditionsa | No. of mutant colonies
|
||
|---|---|---|---|
| Mean | 95% confidence interval | Ratio of test/normal | |
| Standard (10 μmol SUC, 30 μmol QUI, 10-ml plate) | 82 | 75-89 | 1 |
| Double succinate amt (20 μmol SUC, 30 μmol QUI, 10-ml plate) | 141 | 126-157 | 1.72 |
| Double quinate amt (60 μmol QUI, 10-ml plate) | 90 | 81-101 | 1.1 |
| Double plate vol (10 μmol SUC, 30 μmol QUI, 20-ml plate) | 91 | 82-102 | 1.11 |
| Double plate vol and quinate amt (10 μmol SUC, 60 μmol QUI, 20-ml plate) | 93 | 83-104 | 1.13 |
| Double inoculum (100 μl 10−3 overnight culture, 10 μmol SUC, 30 μmol QUI, 10-ml plate) | 80 | 71-91 | 0.98 |
a
In precision plating the total amount of a growth substrate per plate determines the amount of growth; therefore, for succinate (SUC) and quinate (QUI) the total amount per plate rather than the concentration is given. Plates were inoculated under standard conditions with 50 μl of a 10−3 dilution of an overnight culture.