FIG. 2.

Integration of the six-His-tagged ΔxysA gene in the chromosome of B. lactofermentum. (A) Schematic representation of the relevant part of the recipient strain B. lactofermentum chromosome and interpretation of the possible integration results. (B) Southern hybridization analysis. Lambda DNA digested with HindIII (lane 1) and chromosomal DNAs of B. lactofermentum X2 (lane 2), B. lactofermentum X1 (lane 3), and B. lactofermentum R31 (lane 4) digested with BamHI were transferred to nitrocellulose membranes and hybridized separately with the xysA gene (a), with probe 3 (b), and with the kan cassette (c).