Table 3.

rep recA dnaK306 and rep recA dnaK756 mutants are thermosensitive for growth

StrainMutant genotypePlating efficiencya
MC1061Wild type0.9 ± 0.1
TS154 dnaK306 0.9 ± 0.1
JJC529 dnaK306 recA 0.6 ± 0.09
JJC528 dnaK306 rep 0.7 ± 0.3
JJC530 rep recA 1.1 ± 0.5
JJC531 dnaK306 rep recA ≤0.00046 ± 0.00012b
CAG9270Wild type0.8 ± 0.4
CAG9271 dnaK756 0.9 ± 0.09
JJC546 dnaK756 recA 1.1 ± 0.14
JJC547 dnaK756 rep 0.95 ± 0.03
JJC636 rep recA 1.1 ± 0.5
JJC677 dnaK756 rep recA ≤0.046 ± 0.046b
  • a Overnight cultures grown at 30°C were plated at 30 or 40°C. For each culture, the ratio of clones obtained at 40°C to those obtained at 30°C was calculated, and the results are expressed as the average of the ratios.

  • b A few clones were obtained at 40°C that were no longer thermosensitive, indicating that they probably have acquired a compensatory mutation that allows growth at a high temperature. In contrast, rep recA dnaK mutant clones obtained at 30°C were still thermosensitive.