Characterization of a carbofuran-degrading bacterium and investigation of the role of plasmids in catabolism of the insecticide carbofuran

A bacterium capable of using the carbamate insecticide carbofuran as a sole source of carbon and energy, was isolated from soil. The ability to catabolise carbofuran phenol, produced by cleavage of the carbamate ester linkage of the insecticide, was lost at very high frequency when the bacterium was grown in the absence of carbofuran. Plasmid analyses together with curing and mating experiments indicated that the presence of a large plasmid (pIH3, >199 kb) was required for the degradation of carbofuran phenol.Abbreviations Rif^r Rifampicin resistant - Rif^s Rifampicin sensitive - CFH⁺ Carbofuran hydrolase activity present - CFH^- Carbofuran hydrolase activity absent - CFP⁺ ability to degrade carbofuran phenol present - CFP^- ability to degrade carbofuran phenol absent - MS mineral salts medium. MSCF minimal mineral salts medium containing 0.25 mM carbofuran as sole source of carbon and energy - YP MS medium containing 5 g/l yeast extract and 5 g/l Bactopeptone. YPCF as above but with the addition of 1 mM carbofuran - EPTC S-ethyl-N,N-dipropylthiocarbamate - 2,4-D 2,4-dichlorophenoxyacetic acid - NAG N-acetylglucosamine - 3-HB 3-hydroxybutyrate