Table 1. Summary of relative sensitivities to J1 phage infection and predicted transposon insertion loci of J1 phage-resistant mutant.

Strain		Relative J1 phage sensitivitya	Predicted transposon insertion geneb
L. casei	ATCC 27139	1.0	–
	MT77	4.4×10−5	asparagine synthetase (Glutamine-hydrolyzing) asnH
	MT2890	7.5×10−5	chaperone protein dnaJ
	MT3332	1.3×10−4	chaperone protein dnaJ
	MT4156	7.5×10−5	asparagine synthetase (Glutamine-hydrolyzing) asnH
	MT5740	9.1×10−5	chaperone protein dnaJ
	MT6674	9.7×10−5	chaperone protein dnaJ
	MT7279	9.2×10−5	chaperone protein dnaK
	MT7398	9.6×10−5	chaperone protein dnaJ
	MT8105	6.0×10−5	asparagine synthetase (Glutamine-hydrolyzing) asnH

^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.