Fig 6.

guaA, guaB, purA, and purB are essential for bacterial survival in Ham's F-12 medium. (A) CFU counts representing survival of G27 ΔguaA and G27 ΔguaB mutants and their parental strain in nutrient-rich brucella broth supplemented with 10% FBS for 24 h. (B to E) CFU counts representing survival of G27 ΔguaA and G27 ΔguaB mutants and the parental strain in defined medium (Ham's F-12) supplemented with either 10% FBS or increasing concentrations of guanine (B and C), xanthine (D), or increasing concentrations of FBS (E) for 24 h. Starting CFU/ml were between 10⁶ and 10⁷. Dashed lines indicate initial CFU/ml. Error bars represent the standard errors of the means. N/A, no additive.