The grf10Δ mutants are less virulent in a mouse model of infections. (A) Ten Balb/c mice were injected with 1 × 106 cells through the lateral tail vein for each strain and survival was monitored for 15 d post-infection. •, wild type (DAY185); º, heterozygote (RAC114); Δ, homozygous null (RAC117); □, restored strain (RAC120). (B) Mice were sacrificed during the first three days after infection, and kidney homogenates were prepared and plated to determine the extent of colonization (colony forming units per gram; CFU/g). Histogram color: white, 24 h after infection; grey, 48 h after infection; black, 72 h after infection. The GRF10 genotype of the strains used in both panels are wild-type DAY185 (GRF10/GRF10), RAC114 (GRF10/grf10Δ), RAC120 (grf10Δ/grf10Δ::GRF10) and RAC117 (grf10Δ/ grf10Δ).