Possible involvement of plasmids in degradation of malathion and chlorpyriphos by Micrococcus sp.

Two plasmid-harboring strains of Micrococcus sp. (M-36 and AG-43) degrade malathion and chlorpyriphos. Derivatives of the strains (SDS-36 and AO-43) treated with acridine orange and sodium dodecyl sulfate could not utilize malathion and chlorpyriphos for growth as the sole carbon source. Agarose gel electrophoresis of cell extracts of M-36 and AG-43 revealed the presence of a plasmid which was absent in SDS-36 and AO-43--suggesting probable involvement of plasmids in the degradation of malathion and chlorpyriphos by M-36 and AG-43. Nalidixic acid resistance in M-36 was also lost upon elimination of plasmids.