TABLE 4.

Medium composition reverses the sensitivity of the Fusr mutation fusA1 to hydrogen peroxidea

Growth competition mediumCI (fusA1 mutant/WT)b
M93.2 × 10−2
M9 + 70 μM H2O2<1 × 10−6
M9 + 70 μM H2O2 + 1% Casamino Acids1.4 × 10−3
M9 + 70 μM H2O2 + 0.2% glutamine1.4 × 10−3
M9 + 70 μM H2O2 + 0.2% glutamic acid3.5 × 10−4
  • a Media (10 ml) were inoculated with (per milliliter) 106 cells of the wild-type (MM14) and fusA1 (MM142) strains each and incubated in M9 minimal medium with 0.2% glucose (and the indicated additions) for 18 h at 37°C with shaking. The final cell number was approximately 109/ml, which corresponds to about 10 generations of growth.

  • b The competition index (CI) is the ratio of the number of viable fusA1 mutant CFU to the number of wild-type (WT) CFU after 18 h of competition in each medium. A value of <1 × 10−6 means that no viable cells were recovered. Results are the means of results of three independent assays.