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) degr ade malathion and chlorpyriphos. Derivatives of the strains (SDS-36 an d 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-4 3 revealed the presence of a plasmid which was absent in SDS-36 and AO -43 - suggesting probable involvement of plasmids in the degradation o f malathion and chlorpyriphos by M-36 and AG-43. Nalidixic acid resist ance in M-36 was also lost upon elimination of plasmids.