PLASMID AND TRANSPOSON TRANSFER TO THIOBACILLUS-FERROOXIDANS

The broad-host-range IncP plasmids RP4, R68.45, RP1::Tn501, and pUB307 were transferred to acidophilic, obligately chemolithotrophic Thiobac illus ferrooxidans from Escherichia coli by conjugation. A genetic mar ker of kanamycin resistance was expressed in T. ferrooxidans. Plasmid RP4 was transferred back to E. coli from T. ferrooxidans. The broad-ho st-range IncQ vector pJRD215 was mobilized to T. ferrooxidans with the aid of plasmid RP4 integrated in the chromosome of E. coli SM10. pJRD 215 was stable, and all genetic markers (kanamycin/neomycin and strept omycin resistance) were expressed in T. ferrooxidans. By the use of su icide vector pSUP1011, transposon Tn5 was introduced into T. ferrooxid ans. The influence of some factors on plasmid transfer from E. coli to T. ferrooxidans was investigated. Results showed that the physiologic al state of donor cells might be important to the mobilization of plas mids. The transfer of plasmids from E. coli to T. ferrooxidans occurre d in the absence of energy sources for both donor and recipient.