Cadmium toxicity is alleviated by AtLCD and AtDCD in Escherichia coli

Abstract

Aims

Arabidopsis thaliana l‐ and d‐cysteine desulfhydrases (AtLCD and AtDCD) are two important H₂S‐generating enzymes. This study determined the effects of H₂S 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, significantly higher H₂S 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 μmol l⁻¹ Cd stress were noted. We obtained similar results in the wild type treated with NaHS, a H₂S donor. The above changes were substantially counteracted by the mixture of ammonia and pyruvic acid potassium (NH₃ + C₃H₃KO₃), a synthetic inhibitor of H₂S.

Conclusions

AtLCD and AtDCD catalyse the H₂S production, generating an ameliorating effect against Cd‐induced oxidative stress and resulting in E. coli resistance to Cd toxicity.

Significance and Impact of the Study

H₂S as a gasotransmitter is certified to have an ameliorating effect against Cd toxicity, thus providing information for further research regarding the role of H₂S in regulating resistance to the heavy metal stress in organisms.

AtDCD, AtLCD, cadmium toxicity, hydrogen sulfide, oxidative stress