Plasmid curing from an acidophilic bacterium of the genus Acidocella

Preservation of the acidophilic heterotroph, Acidocella sp. strain GS19h, a t 4 degrees C in stab culture eliminated all indigenous plasmids from this bacterium. Growth at 42 degrees C initially caused changes in the plasmid p rofile followed by total elimination of plasmids after 10 cycles of growth. Concomitant to this loss of all plasmids, the cured derivatives became sen sitive to CdSO4 and ZnSO4, and the MIC value of the salts dropped from 1 M for each in the case of parental strain to 2. mM and 5 mM, respectively, su ggesting plasmid-mediated inheritance of metal resistance in this bacterium . The cured derivatives could not utilise lactose, indicating this metaboli c activity to be plasmid-associated in this strain. (C) 2000 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.