Activities of antioxidant enzymes in three bacteria exposed to bensulfuron-methyl.

Oxidative stress enzymes, superoxide dismutase (SOD), catalase (CAT), and ATPase, from two Gram-positive bacteria and one Gram-negative bacterium, respectively, were tested for response to the oxidative stress caused by bensulfuron-methyl (BSM). Native PAGE was used to detect the SOD isoenzyme profiles of these bacteria. All three bacteria possessed a basal level of SOD, CAT, and ATPase activity prior to being exposed to BSM. Enzyme activities changed in a BSM-concentration-dependent manner after exposure to BSM for 24 h. Activity of all the enzymes was increased and reached the first activity peak after being exposed to BSM at 1 or 1.5 h, respectively, then a decline occurred, and after that another simulation appeared at 9h or 14 h. Only one and three detectable SOD isoenzyme bands were observed in Gram-positive strains and the Gram-negative strain, respectively. BSM could bring short-term ecotoxicity to three bacteria, but the effect of BSM was not lethal.