ISOLATION OF AN R(-) M(+) MUTANT OF YERSINIA-ENTEROCOLITICA SEROTYPE O-8 AND ITS APPLICATION IN CONSTRUCTION OF ROUGH MUTANTS UTILIZING MINI-TN5 DERIVATIVES AND LIPOPOLPSACCHARIDE-SPECIFIC PHAGE

A generally applicable procedure,vas used to isolate a spontaneous restriction-deficient mutant of Yersinia enterocolitica serotype 0:8. Transposition frequency in the mutant strain 8081-res was approximately 6.7 x 10(-6) per recipient, chile it was practically zero in the wild-type strain 8081-c. Mobilization frequency into 8081-res was 10(5) times higher than that into the wild-type strain. The mutant had lost the ability to express the YenI restriction endonuclease activity present in serotype 0:8 strains. This allowed the construction of a transposon library in 8081-res. Insertion mutants with transposons in the genes of the rfa region were selected from this library.