Genetic organization of the immediate environment of the chromosomal urease (ure) locus and genotype analysis of ynt- and ureH-deficient mutants of Y. pseudotuberculosis 32777. (A) KpnI (K) and EcoRI (E) restriction map of the chromosome of wild-type strain 32777 and isogenic mutants MYUH (ureH) and MYNT (ynt). (B) (Left) Southern blot of KpnI-digested DNA from wild-type strain 32777 and the yntABCDE-deficient mutant hybridized with probe 1 (0.5 kb, corresponding to the downstream region of yntE) and probe 2 (1.4 kb, detecting the chloramphenicol resistance gene cat). (Right) Southern blot of EcoRI-digested DNA from wild-type strain 32777 and the ureH-deficient mutant hybridized with probe 3 (0.6 kb, corresponding to the upstream region of ureH) and probe 4 (1.3 kb, detecting the kanamycin resistance gene aphA-1a). Primers N1 to N12, K1, K2, C1, and C2 were used both for creating mutants and for checking their genotype. Numbers in parentheses indicate the DNA sequence coordinates.