S(-II) reactivates Cd2+-stressed Shewanella oneidensis via promoting low-molecular-weight thiols synthesis and activating antioxidant defense

Siyu Zhang, Changdong Ke, Mengge Jiang, Yuancheng Li, Weilin Huang, Zhi Dang, Chuling Guo

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Efficient remedies for living organisms including bacteria to counteract cadmium (Cd2+) toxicity are still highly needed. Plant toxicity studies have showed that exogenous S(-II) (including hydrogen sulfide and its ionic forms, i.e., H2S, HS, and S2−) application can effectively alleviate adverse effects of Cd stress, but whether S(-II) could mitigate bacterial Cd toxicity remains unclear. In this study, S(-II) was applied exogenously to Cd-stressed Shewanella oneidensis MR-1 and the results showed that S(-II) can significantly reactivate impaired physiological processes including growth arrest and enzymatic ferric (Fe(III) reduction inhibition. The efficacy of S(-II) treatment is negatively correlated with the concentration and time length of Cd exposure. Energy-dispersive X-ray (EDX) analysis suggested the presence of cadmium sulfide inside cells treated with S(-II). Both compared proteomic analysis and RT-qPCR showed that enzymes associated with sulfate transport, sulfur assimilation, methionine, and glutathione biosynthesis were up-regulated in both mRNA and protein levels after the treatment, indicating S(-II) may induce the biosynthesis of functional low-molecular-weight (LMW) thiols to counteract Cd toxicity. Meanwhile, the antioxidant enzymes were positively modulated by S(-II) and thus the activity of intracellular reactive oxygen species was attenuated. The study demonstrated that exogenous S(-II) can effectively alleviate Cd stress for S. oneidensis likely through inducing intracellular trapping mechanisms and modulating cellular redox status. It suggested that S(-II) may be a highly effective remedy for bacteria such as S. oneidensis under Cd-polluted environments.

Original languageEnglish (US)
Article number121516
JournalEnvironmental Pollution
Volume327
DOIs
StatePublished - Jun 15 2023

All Science Journal Classification (ASJC) codes

  • Toxicology
  • Pollution
  • Health, Toxicology and Mutagenesis

Keywords

  • Antioxidant system
  • Assimilatory sulfate reduction
  • Cadmium detoxification
  • Hydrogen sulfide
  • Iron-reducing bacteria

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