TABLE 3.

Influence of plate conditions on precision plating

Growth conditionsaNo. of mutant colonies
Mean95% confidence intervalRatio of test/normal
Standard (10 μmol SUC, 30 μmol QUI, 10-ml plate)8275-891
Double succinate amt (20 μmol SUC, 30 μmol QUI, 10-ml plate)141126-1571.72
Double quinate amt (60 μmol QUI, 10-ml plate)9081-1011.1
Double plate vol (10 μmol SUC, 30 μmol QUI, 20-ml plate)9182-1021.11
Double plate vol and quinate amt (10 μmol SUC, 60 μmol QUI, 20-ml plate)9383-1041.13
Double inoculum (100 μl 10−3 overnight culture, 10 μmol SUC, 30 μmol QUI, 10-ml plate)8071-910.98
  • 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.