TABLE 1

Efficiency of sporulation-dependent spo0A knockout during vegetative growth and during sporulationa

StrainCre recombinase expression locusCre recombinase expression promoter% knockout efficiency ± SD during:
Vegetative growthSporulation
BMB1710.00 ± 0.000.00 ± 0.00
BT-008BMB171_C4815BMB171_C05360.04 ± 0.0499.77 ± 0.02
BT-009BMB171_C1559BMB171_C05360.03 ± 0.0270.64 ± 1.14
BT-010BMB171_C4815BMB171_C42860.09 ± 0.0299.96 ± 0.04
BT-011BMB171_C1559BMB171_C42860.03 ± 0.0296.43 ± 0.08
  • a For measurement of efficiency during vegetative growth, cells were grown in 10 ml of LB broth until the OD600 reached approximately 1.4 to 1.6. One milliliter of the culture was serially diluted in 0.9% (wt/vol) NaCl and spread on DSM agar plates. For measurement of efficiency during sporulation, spores were prepared in GYS medium, and 1 ml of the culture was sampled. After heat treatment at 65°C for 30 min, the spores were serially diluted in PBS solution and spread on DSM agar plates. The plates were incubated overnight at 30°C and then left for 1 day at room temperature. Then, approximately 2,500 colonies were counted. White colonies were counted as wild-type colonies, and gray colonies were counted as spo0A knockout colonies. Experiments were performed three times independently.