Effect of Thiols, Zinc, and Redox Conditions on Hg Uptake in Shewanella oneidensis

Aleksandra Szczuka, Francois M. M. Morel, Jeffra K. Schaefer

Research output: Contribution to journalArticle

27 Scopus citations

Abstract

Mercury uptake in bacteria represents a key first step in the production and accumulation of methylmercury in biota. Previous experiments with mercury methylating bacteria have shown that Hg uptake is enhanced by some thiols, in particular cysteine, and that it is an energy-dependent process through heavy metal transporters [Schaefer et al. Environ. Sci. Technol. 2014, 48, 3007]. In this study, we examine Hg uptake in the nonmethylating facultative aerobe, Shewanella oneidensis, under both anaerobic and aerobic conditions. Our results demonstrate similar characteristics of the Hg uptake system to those of the Hg methylating strains: (1) uptake is enhanced in the presence of some thiols but not others; (2) uptake is energy dependent as evidenced by inhibition by a protonophore, and (3) uptake is inhibited by high Zn(II) concentrations. Initial cellular uptake rates in S. oneidensis were remarkably similar under aerobic and fumarate-reducing conditions. These data support a similar Hg(II) uptake mechanism within the proteobacteria of accidental Hg(II) transport through heavy metal transporters with similar rates of uptake but differences in the ability to take up Hg bound to different thiols.

Original languageEnglish (US)
Pages (from-to)7432-7438
Number of pages7
JournalEnvironmental Science and Technology
Volume49
Issue number12
DOIs
StatePublished - Jun 16 2015

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Environmental Chemistry

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