Table 3 Formation of reactive oxygen species (ROS) in various bacterial species when exposed to selenite and tellurite

Selenite

 E. coli

2D-electrophoresis of soluble and membrane fractions from cell extracts

SOD induction but only in cells grown aerobically in the presence of selenite

[89]

 E. coli

Construction of mutants (ΔsodA, ΔsodB, ΔtrxA, ΔtrxB, Δgor, ΔgshA)

Strains lacking either sodA or sodB were hypersensitive to selenite. Deletions of either trxA, trxB, gor, and gshA had no effect on selenite sensitivity

[89]

 E. coli

In vivo use of the fluorescent ROS-sensitive probe DCFH-DA after exposure to selenite

Strong increase of fluorescence in cells exposed to selenite

[48]

Tellurite

 R. capsulatus

Non-denaturing PAGE of lysates from cells treated with tellurite (or paraquat)

Strong increase of SOD activity in cells treated with tellurite (or paraquat)

[97]

 E. coli, S. epidermidis

Construction of mutants

(ΔkatG)

A katG minus mutant was hypersentive to tellurite; expression of kat gene of S.epidermis in E.coli increases in the latter resistance to tellurite

[138]

 E. coli

Use of the fluorescent ROS-sensitive probe DCFH-DA in extracts of cells exposed to tellurite

Increase of the fluorescence as a function of tellurite concentration

[155]

 E. coli

DNA fragments amplification of genes (sodA, sodB, katG, soxS, gapA)

Increase of sodA and sodB with a strong induction of katG and soxS mRNA synthesis in the presence of tellurite

[155]

 Pseudomonas pseudoalcaligenes

In vivo use of the fluorescent ROS-sensitive probe DCFH-DA after exposure to tellurite

Strong increase of fluorescence in cells exposed to tellurite

[103]