Effect of thioredoxin on the sensitivity of bacteria to chemical damage

The ability of thioredoxin (Trx) to protect cells from chemical damage was determined by comparing the growth of a control strain of Escherichia coli JM101 and isogenic strain transformed with the plasmid pKKTS1 containing th e Streptomyces aureofaciens thioredoxin gene, in the presence of the nucleo side analogs arabinosylcytosine, 5-fluorouridine, ftorafur and carcinogen b eta-naftylamine. Arabinosylcytosine showed no effect on the growth of eithe r of the two strains. 5-fluorouridine, ftorafur [1-((R, S)-tetrahydrofuran- 2-yl)-5-fluorouracil] and beta-naftylamine demonstrated lower inhibitory ef fects on the growth of the thioredoxin overproducing strain than on the gro wth of the control strain. These results suggested that Trx could protect t he cells from chemical damage under certain metabolic conditions.