Summary of relative sensitivities to J1 phage infection and predicted transposon insertion loci of J1 phage-resistant mutant.

a The cells of L. casei ATCC 27139 and isogenic Tn5 insertion mutants (1.0×107 CFU/ml) were combined with J1 phage (5.0×106 PFU/ml) in ILS broth at an moi of 0.5, and PFU were counted after incubation at 37°C for 24 h. The relative sensitivities to J1 phage were assessed as the ratio of PFU for transposon insertion mutants to that of the wild-type strain.b The genes into which transposons were inserted were identified using BLAST.