||B. subtilis 110NA strain (trpC2, spoOA3, su–) , harbouring plasmid pPR55w6, a pUB110-derivative containing Ø29 gene 6, except where indicated. Infections were carried out with phage Ø29 sus14 (1242), a delayed lysis mutant with an otherwise wild-type phenotype , sus3 (91) a replication-null mutant, sus17 or sus16.7 (48)/sus14 (1242), replication-defective mutants. Bacteria were grown in LB broth supplemented with 5 mM MgSO4. Phleomycin, from Cayla SARL, was added to the medium at a final concentration of 0.8 µg ml-1.