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. 2007 Jan 23;35(3):930–938. doi: 10.1093/nar/gkl1145

Figure 2.

Figure 2.

Generation time of various E. coli strains in the presence or absence of d-amino acids in the growth medium. Strains K37ΔrecAλDE3 (dtd+) or K37ΔrecAΔtyrHλDE3 (Δdtd) cells containing pET15blpa or pET15blpa::GEK1 were grown at 37°C in M9-glucose minimal medium containing 100 μg/ml ampicillin and either 2.4 mM d-tyrosine or 11 mM d-aspartic acid. A control without d-amino acid was also performed. Cells were pre-grown overnight in the growth medium under study. For generation time measurements, inoculations were adjusted to an OD650 of 0.05. Samples were withdrawn from the cultures every 90 min during 540 min, and generation times were deduced from OD650 measurements. Shown experiments were performed using wild-type strain (K37ΔrecAλDE3) carrying pET15blpa (light bars), Δdtd mutant strain (K37▵recA▵tyrHλDE3) carrying pET15blpa (middle dark bars) and Δdtd mutant strain (K37▵recA▵tyrHλDE3) carrying pET15blpa::GEK1 (dark bars). Errors bars represent standard deviations calculated from two independent experiments. In the case of the strain K37ΔrecAΔtyrHλDE3 carrying pET15blpa grown in the presence of 11 mM d-aspartic acid, the increase in the OD650 value was less than 35% after 540 min. Therefore, only an approximate value of the generation time could be estimated.