Mobilization of "nonmobilizable" plasmids by the aggregation- mediated conjugation system of Bacillus thuringiensis

Tidsskriftartikel - 1996

Resume

The aggregation-mediated conjugation system ofBacillus thuringiensissubsp.israelensis(Bti), encoded by the 200-kb plasmid pXO16, is highly potent in transferring itself and efficient in mobilizing other nonconjugative plasmids. In the present study we have analyzed the nativeBacillus cereusplasmid pBC16. This plasmid has previously been shown to harbor amobgene (ORF) and a locus functioning as anoriT site in plasmid pLS20-mediated conjugation inBacillus subtilis.However, in the conjugation system ofBtiwe found that a derivative of pBC16 deleted for both these loci was mobilizable, although at a reduced frequency. Another derivative of pBC16, containing a deletion spanning the first half of the coding region of themobgene, was found to be nearly as mobilizable as the intact pBC16, suggesting its dispensability in the transfer process. Other plasmids based on the -replicating origins, pAM1, pLS20,ori43, ori44,andori60,were also consistently mobilized in the conjugation system encoded byBtiplasmid pXO16. Analyzing the conjugation process by the use of scanning electron microscopy revealed the presence of connections between cells in the mating mixtures. These connections did not appear in monocultures of the donor strain or the recipient strain and may be conjugational junctions.

Reference

Andrup L, Jørgensen O, Wilcks A, Smidt L, Jensen G. Mobilization of "nonmobilizable" plasmids by the aggregation- mediated conjugation system of Bacillus thuringiensis. Plasmid 1996;36(2):75-85.
doi: 10.1006/plas.1996.0035

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