title: The aggregation-mediated conjugation system of Bacillus thuringiensis subsp. israelensis: host range and kinetics of transfer.
abstract: The aggregation-mediated conjugation system in Bacillus thuringiensis subsp. israelensis encoded on the plasmid pXO16 is characterized by the formation of aggregates when Agr+ and Agr- cells are socialized in exponential growth. Using the aggregation phenotypes, we have identified potential recipients of the aggregation-plasmid pXO16 among Bacillus cereus, Bacillus subtilis, Bacillus megaterium, Bacillus sphaericus, and 24 subspecies of B. thuringiensis. We found 14 Agr- strains, i.e., potential recipients of the aggregation system encoded by plasmid pXO16. Five strains contained a conjugative apparatus of their own and were excluded from further examinations. To monitor the transfer of plasmid pXO16, we constructed a transposon insertion of the plasmid with Tn5401. The study of the plasmid transfer of pXO16::Tn5401 indicated the secretion of bacteriocins from both donor strain and recipient strains. Only one out of the nine strains examined was unable to receive the aggregation-plasmid pXO16 and express the aggregation phenotype and the conjugative abilities. It was found that the transfer of plasmid pXO16 to Bacillus thuringiensis subsp. israelensis Agr- strains was 100%. All recipients had acquired the aggregation-plasmid pXO16 and converted to the Agr+ phenotype.
authors.affiliation: National Institute of Occupational Health, Department of Toxicology and Biology, Lerso Parkallé 105, DK-2100 Copenhagen, Denmark.
authors.forename: G B
authors.initials: GB
authors.lastname: Jensen
authors.forename: L
authors.initials: L
authors.lastname: Andrup
authors.forename: A
authors.initials: A
authors.lastname: Wilcks
authors.forename: L
authors.initials: L
authors.lastname: Smidt
authors.forename: O M
authors.initials: OM
authors.lastname: Poulsen
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001407:Bacillus / Q000235:genetics; D001413:Bacillus thuringiensis / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development; D001430:Bacteriocins / Q000096:biosynthesis / Q000378:metabolism; D003227:Conjugation, Genetic / Q000235:genetics*; D004247:DNA / Q000032:analysis; D004251:DNA Transposable Elements; D004587:Electrophoresis, Agar Gel; D016254:Mutagenesis, Insertional; D010957:Plasmids / Q000235:genetics; D013752:Tetracycline / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D001430:Bacteriocins; D004251:DNA Transposable Elements; D004247:DNA; D013752:Tetracycline