Article Figures & Data
Figures
- Fig. 1.
Alkyl hydroperoxide reductase gene in S. pyogenes. The position and direction of the ahpC gene is depicted relative to its neighbors in the genome. The percent amino acid identity and similarity to the closest match found by a TBlastN search are shown. The region inserted into the reporter plasmid for expression studies is underlined. Below is a partial alignment of theS. pyogenes ahpC gene with the Salmonella enterica serovar Typhimurium homologue. Regions around the conserved cysteines (C46 and C165) are shown. The 45-amino-acid region removed by deletion is indicated by the arrows.
- Fig. 2.
Glutathione peroxidase gene in S. pyogenes. The position and direction of gpoA is shown relative to its upstream neighbor. The percent amino acid identity and similarity for the closest match found in a TBlastN search are shown. The region inserted into the reporter plasmid for expression studies is underlined. Below is a partial alignment of four glutathione peroxidase genes, showing the conserved cysteine (C36), asparagine (N99), and C-terminal region (including N125). The region of the in-frame deletion is indicated by arrows. In the process of making the deletion, a proline and a glycine (underlined) were replaced by arginines.
- Fig. 3.
Methyl viologen sensitivity of ahpC andgpoA mutants. Methyl viologen (MV) sensitivity ofahpC and gpoA mutants. The growth of HSC5 (wild type), HAHP (ΔAhpC), and HGLT (ΔGpoA) in the absence (no treatment) or presence of the indicated concentrations of methyl viologen are shown. Where indicated, cultures were supplemented with catalase or hemoglobin (see Materials and Methods). Growth was measured by determining the OD600 after 18 h of incubation. A representative experiment is shown. Similar experiments were done with HAG, JRS4, and mutants derived from JRS4 (JAHP, JGLT, and JAG, see Table 1), with similar results.
- Fig. 4.
Induction of resistance response by hydrogen peroxide and ethanol. Bacterial cultures were induced with a sublethal dose of hydrogen peroxide before challenge with a lethal dose. The relative survival was calculated as the percentage of CFU after lethal peroxide challenge divided by the percentage of wild-type cells surviving the same challenge (black bars). Some cultures were not induced before challenge. Other cultures were induced with agents other than hydrogen peroxide (as indicated) before lethal challenge with H2O2. Each bar represents the average of at least two independent experiments, each done in triplicate. Error bars represent the standard error of the mean.
- Fig. 5.
Gene encoding PerR in S. pyogenes. The position and direction of perR are depicted relative to its neighbors in the genome as published by the Sanger Centre. This chromosomal structure is similar to that of the strains used in this study but is different from that of the M1 strain published by the University of Oklahoma. The percent amino acid identity and similarity to the closest match found by a TBlastN search are shown. Below is a partial alignment of the S. pyogenes perR gene with theB. subtilis homologue. Regions around the conserved putative helix-turn-helix DNA binding site and the putative metal-binding domain are shown. Two conserved CXXC putative metal-binding site motifs are shown in boxes. The 66-amino-acid region removed by deletion is indicated by the arrows. In the process of making the deletion, a valine and a tyrosine were replaced by a valine and an aspartic acid (underlined).
- Fig. 6.
PerR is important for the inducible peroxide resistance response. The HΔPer mutant was compared to wild-type cells for the inducible peroxide resistance response. The relative survival was calculated as described in Fig. 4. Data for the wild type are shown in white; data for the HΔPer mutant are shown in black. The data represent the average of eight independent experiments. Error bars represent the standard error of the mean.
Tables
- Table 1.
S. pyogenes strains
Strain Relevant genotype Characteristic Source or reference HSC5 Wild type 26 HAHP ahpCΔ133–292 ahpCinactivated in HSC5 This work HGLT gpoAΔ42–212 gpoAinactivated in HSC5 This work HAGa ahpCΔ133–292gpoAΩpKK15 gpoA inactivated in HAHP This work JRS4 Wild type 49 JAHP ahpCΔ133–292 ahpCinactivated in JRS4 This work JAG ahpCΔ133–292gpoAΔ42–212 ahpC andgpoA inactivated in JRS4 This work HΔPer perRΔ1–198 perRinactivated in HSC5 This work ↵a Strained derived by integration of the given plasmid into the indicated strain.
