FIG. 4.

Southern blot analysis of B. subtilis transconjugants containing attTn. B. subtilis cells containing attTn were used as recipients in matings with C. difficile containing Tn5397. DNA was prepared from transconjugants and digested with HindIII and probed with tndX. If the element were integrating into the attTn site, one would expect to see two hybridizing fragments, one of 5,425 bp internal to Tn5397 (Fig. 1 and 2) and one of 2,387 bp (or 603 bp, depending the orientation of the transposon in the genome), whereas insertion elsewhere in the genome would yield the 5,425-bp band and one of variable size representing the junction region. The results of Southern blotting of eight transconjugants are shown (see the text for more details).