Conjugative plasmid mediated inducible nickel resistance in Hafnia alvei 5-5.
Hafnia alvei 5-5, isolated from a soil-litter mixture underneath the canopy of the nickel-hyperaccumulating tree Sebertia acuminata (Sapotaceae) in New Caledonia, was found to be resistant to 30 mM Ni(2+) or 2 mM Co(2+). The 70-kb plasmid, pEJH 501, was transferred by conjugation to Escherichia coli, Serratia marcescens, and Klebsiella oxytoca. Transconjugant strains expressed inducible nickel resistance to between 5 and 17 mM Ni(2+), and cobalt resistance to 2 mM Co(2+). A 4.8-kb Sal- EcoRI fragment containing the nickel resistance determinant was subcloned, and the hybrid plasmid was found to confer a moderate level of resistance to nickel (7 mM Ni(2+)) even to E. coli. The expression of nickel resistance was inducible by exposure to nickel chloride at a concentration as low as 0.5 mM Ni(2+). By random Tn phoA'-1 insertion mutagenesis, the fragment was shown to have structural genes as well as regulatory regions for nickel resistance. Southern hybridization studies showed that the nickel-resistance determinant from pEJH501 of H. alvei 5-5 was homologous to that of pTOM9 from Alcaligenes xylosoxydans 31A.
Department of Biology, Research Institute for Basic Science, Kyunghee University, 130-701, Seoul, Korea.
Jeong Eun
JE
Park
Kho Eun
KE
Young
Hans-Günter
HG
Schlegel
Ho Gun
HG
Rhie
Ho Sa
HS
Lee
D001419:Bacteria / Q000145:classification / Q000235:genetics; D003001:Cloning, Molecular; D003227:Conjugation, Genetic; D015342:DNA Probes; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D020611:Hafnia alvei / Q000187:drug effects* / Q000235:genetics* / Q000502:physiology; D008826:Microbial Sensitivity Tests; D008957:Models, Genetic; D009154:Mutation; D009532:Nickel / Q000378:metabolism / Q000494:pharmacology*; D010957:Plasmids / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid
D015342:DNA Probes; D009532:Nickel