FUNCTIONAL COMPARISON OF CONJUGATIVE TRANSPOSONS TN916 AND TN925

During interspecies matings between Bacillus subtilis and Bacillus thu ringiensis subsp, israelensis, transfer of conjugative transposon Tn91 6 was detected at a frequency of 1.1 X 10(-4) transconjugants per dono r. Tn916-dependent transfer of plasmids pC194 and pE194 was detected a t frequencies of 1.4 x 10(-5) and 3.2 x 10(-7) transconjugants per don or, respectively. Similar frequencies were obtained during parallel ma tings with otherwise isogenic strains that contain Tn925 instead of Tn 916. Tn916- or Tn925-dependent transfer of plasmids pC194 or pUB110 fr om the recipient to the donor (retrotransfer) was not observed during inter- or intraspecies matings. Transposon-mediated plasmid transfer b y Tn916 and Tn925 is a Rec independent event. Thus, the data from stud ies in which otherwise isogenic donor and recipient strains were used indicated that Tn916 and Tn925 are, from a functional point of view, m uch more similar than previously suggested. (C) 1996 Academic Press, I nc.