Tellurite effects on Rhodobacter capsulatus cell viability and superoxide dismutase activity under oxidative stress conditions

Francesca Borsetti, Valentina Tremaroli, Francesca Michelacci, Roberto Borghese, Christine Winterstein, Fevzi Daldal, Davide Zannoni

Research output: Contribution to journalArticle

Abstract

Cells of the facultative photosynthetic bacterium Rhodobacter capsulatus (MT1131 strain) incubated with 10 μg ml-1 of the toxic oxyanion tellurite (TeO3 2-) exhibited an increase in superoxide dismutase activity. The latter effect was also seen upon incubation with sublethal amounts of paraquat, a cytosolic generator of superoxide anions (O2 •-), in parallel with a strong increase in tellurite resistance (TeR). A mutant strain (CW10) deficient in SenC, a protein with similarities to peroxiredoxin/thiol:disulfide oxidoreductases and a homologue of mitochondrial Sco proteins, was constructed by interposon mutagenesis via the gene transfer agent system. Notably, the absence of SenC affected R. capsulatus resistance to periplasmic O2 •- generated by xanthine/xanthine oxidase but not to cytosolic O2 •- produced by paraquat. Further, the absence of SenC did not affect R. capsulatus tellurite resistance. We conclude that: (1) cytosolic-generated O2 •- enhances TeR of this bacterial species; (2) small amounts of tellurite increase SOD activity so as to mimic the early cell response to oxidative stress; (3) SenC protein is required in protection of R. capsulatus against periplasmic oxidative stress; and finally, (4) SenC protein is not involved in TeR, possibly because tellurite does not generate O2 •- at the periplasmic space level.

Original languageEnglish
Pages (from-to)807-813
Number of pages7
JournalResearch in Microbiology
Volume156
Issue number7
DOIs
Publication statusPublished - Aug 2005

Keywords

  • Oxidative stress
  • Rhodobacter capsulatus
  • SenC protein
  • Superoxide dismutase
  • Tellurite

ASJC Scopus subject areas

  • Applied Microbiology and Biotechnology
  • Microbiology

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    Borsetti, F., Tremaroli, V., Michelacci, F., Borghese, R., Winterstein, C., Daldal, F., & Zannoni, D. (2005). Tellurite effects on Rhodobacter capsulatus cell viability and superoxide dismutase activity under oxidative stress conditions. Research in Microbiology, 156(7), 807-813. https://doi.org/10.1016/j.resmic.2005.03.011