Heavy metal resistant Arthrobacter sp.--a tool for studying conjugational plasmid transfer between gram-negative and gram-positive bacteria.

The role of two heavy metal-resistant strains of the Gram-positive genus Arthrobacter sp. as a tool in studying conjugational plasmid transfer between Gram-positive and Gram-negative bacteria is described. The high nickel resistance and the cobalt resistance of Arthrobacter sp. strain RM1/6 could be transferred to Arthrobacter sp. strain WS14. IncQ plasmids (pKT240, pKT240::czc, pML10) could be mobilized from E. coli into Arthrobacter spp. strains; antibiotic (Km, Ap, Tc) and heavy metal (Co) resistance genes were expressed in the recipient stains. IncQ plasmid pKT240 could be mobilized between Arthrobacter spp. strains. IncP plasmid RP4::Tn4371 was transferred from A. eutrophus to Arthrobacter sp., RP4-mediated antibiotic resistance to Km was expressed in the recipient strain.