Table 1.
Primers used in this work.
Table 2.
Bioinformatic characterization of predicted Trx.
Figure 1.
Glutathione reductase activity.
The protein crude extract from L. ferriphilum (gray) were obtained after 1 hour of exposure to 0, 150, 250, or 260 mM Fe3+. E. coli (black) and H. pylori (light gray) were used as positive and negative controls, respectively. Bars represent µmol of oxidized NADPH by µgram of protein per min during 15 min of incubation (initial velocity). The average was calculated from three independent trials (lines on top of bars represent values range).
Figure 2.
The reduction of the insulin alfa-chain was monitored at 650 nm in bacteria treated with 260 mM Fe3+, 4 mM diamide, or 1 mM H2O2, at 30 (A) or 60 minutes (B) of stress exposure. The reaction was performed as described in materials and methods after 15 min of incubation. Activity in the control reaction corresponds to 100%. Data represents the average of two independent trials (lines on top of bars indicate values range). The negative control (mixture without protein) did not reduced insulin alfa-chain at 15 min.
Figure 3.
Comparison of thioredoxin activity between L. ferriphilum and neutrophilic bacteria.
The reduction of the insulin alfa-chain was monitored at 650 nm for 25 minutes in E. coli (triangle), B. subtilis (circle) and L. ferriphilum (square) after 4 mM diamide exposure during 60 minutes (close figures). Controls are shown with open figures. The negative control (mixture without protein) did not reduced insulin at 30 min. This data represents 2 independent trials.
Figure 4.
Thioredoxin reductase activity.
The reduction of DTNB to TNB was monitored at 412 nm in bacteria treated with 260 mM Fe3+, 4 mM diamide, or 1 mM H2O2, at 30 (A) or 60 minutes (B) of stress exposure. The reaction was performed as described in materials and methods during 3 min of incubation (initial velocity). The data is normalized by the negative control (mixture without protein). This data represents the mean of 2 independent trials. Bars indicate values range.
Figure 5.
Time-course curve of Trx and TR relative activity.
Activities of TR (square) and Trx (triangle) were measured every 10 minutes until 60 minutes after exposure to 260 mM Fe3+. This data represents the mean of 3 independent trials (bars indicate values range). All data are normalized by their respective controls.
Figure 6.
Relative expression of trx genes in oxidative stressed L. ferriphilum.
Bacteria were treated with 260 mM Fe3+ (gray) or 4 mM diamide (Black) for 20 or 50 min. Cells grown under standard growth conditions were used as negative control (white). Data was normalized by 16S rRNA. Data represents the average of 3 independent trials (bars indicate values range).