EFFECTS OF INTRACELLULAR GLUTATHIONE ON SENSITIVITY OF ESCHERICHIA-COLI TO MERCURY AND ARSENITE

The effect of intracellular glutathione on sensitivity to mercuric cat ions and arsenite anions was studied in Escherichia coli mutants that lack glutathione (gshA) with or without an additional mutation affecti ng the osmotregulant trehalose. The absence of glutathione increased c ellular sensitivity to both Hg2+ and AsO2-. The double mutant was more sensitive to Hg2+ than the single mutant strain. The addition of plas mid resistance determinants of Hg2+ and AsO2- showed additivity betwee n chromosomal genes and plasmid genes. Mercury resistance was increase d in the plasmid-containing cells but not up to the level of wild-type cells. Plasmid arsenite resistance was not expressed in the gshA muta nt of E. coli. (C) 1998 Academic Press.