Cadmium toxicity is alleviated by AtLCD and AtDCD in Escherichia coli.

摘要

Aims: Arabidopsis thaliana L- and D-cysteine desulfhydrases (AtLCD and AtDCD) are two important H2 S-generating enzymes. This study determined the effects of H2 S derived from AtLCD and AtDCD on cadmium (Cd) toxicity in Escherichia coli. Methods and Results: AtLCD and AtDCD were cloned into pET28a vectors and transformed into wild-type E. coli strain BL21(DE3), named BL21(LCD) and BL21(DCD). In the induced BL21(LCD) and BL21(DCD) compared with wild type, signi?cantly higher H2 S generation rates were observed. Additionally, higher survival rates, reduced contents of malondialdehyde (MDA) and hydrogen peroxide (H2O2 ), decreased activities of superoxide dismutase and catalase under 220 lmol l 1 Cd stress were noted. We obtained similar results in the wild type treated with NaHS, a H2 S donor. The above changes were substantially counteracted by the mixture of ammonia and pyruvic acid potassium (NH3 + C3H3KO3 ), a synthetic inhibitor of H2 S. Conclusions: AtLCD and AtDCD catalyse the H2 S production, generating an ameliorating effect against Cd-induced oxidative stress and resulting in E. coli resistance to Cd toxicity. Signi?cance and Impact of the Study: H2 S as a gasotransmitter is certi?ed to have an ameliorating effect against Cd toxicity, thus providing information for further research regarding the role of H2 S in regulating resistance to the heavy metal stress in organisms.