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The putative thiosulfate sulfurtransferases PspE and GlpE contribute to virulence of Salmonella Typhimurium in the mouse model of systemic disease.

Wallrodt I, Jelsbak L, Thorndahl L, Thomsen LE, Lemire S, Olsen JE - PLoS ONE (2013)

Bottom Line: Since the double mutant, which was the one affected in virulence, was not affected in this assay, we concluded that resistance to oxidative stress and the virulence phenotype was most likely not linked.The two genes did not contribute to nitric oxid stress, to synthesis of essential sulfur containing amino acids, nor to detoxification of cyanide.Currently, the precise mechanism by which they contribute to virulence remains elusive.

View Article: PubMed Central - PubMed

Affiliation: Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.

ABSTRACT
The phage-shock protein PspE and GlpE of the glycerol 3-phosphate regulon of Salmonella enterica serovar Typhimurium are predicted to belong to the class of thiosulfate sulfurtransferases, enzymes that traffic sulfur between molecules. In the present study we demonstrated that the two genes contribute to S. Typhimurium virulence, as a glpE and pspE double deletion strain showed significantly decreased virulence in a mouse model of systemic infection. However, challenge of cultured epithelial cells and macrophages did not reveal any virulence-associated phenotypes. We hypothesized that their contribution to virulence could be in sulfur metabolism or by contributing to resistance to nitric oxide, oxidative stress, or cyanide detoxification. In vitro studies demonstrated that glpE but not pspE was important for resistance to H2O2. Since the double mutant, which was the one affected in virulence, was not affected in this assay, we concluded that resistance to oxidative stress and the virulence phenotype was most likely not linked. The two genes did not contribute to nitric oxid stress, to synthesis of essential sulfur containing amino acids, nor to detoxification of cyanide. Currently, the precise mechanism by which they contribute to virulence remains elusive.

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Related in: MedlinePlus

Growth of WT (4/74) and pspE and glpE mutated and complemented strains in M9 medium with 10 mM H2O2.Wild type (black), ΔglpE (blue), ΔpspE (green), ΔglpE/ΔpspE (red) and ΔglpE+glpE strains were inoculated to an OD600 value of 0.05, H2O2 was added and growth was followed for 16 hours. Results shown are representative of two biological repeats.
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pone-0070829-g004: Growth of WT (4/74) and pspE and glpE mutated and complemented strains in M9 medium with 10 mM H2O2.Wild type (black), ΔglpE (blue), ΔpspE (green), ΔglpE/ΔpspE (red) and ΔglpE+glpE strains were inoculated to an OD600 value of 0.05, H2O2 was added and growth was followed for 16 hours. Results shown are representative of two biological repeats.

Mentions: Like nitric oxide, H2O2 also affects the cell through damage of iron- clusters [56], and we found it indicated to investigate the role of GlpE and PspE in the protection against this oxidative stress molecule. We grew our mutants in the presence of 5 mM and 10 mM H2O2 in LB and M9 media and observed that the wild type strain was slightly affected in growth and that the ΔglpE, but not the ΔpspE mutant, was severely affected in growth under this condition in both media (growth in 10 mM H2O2 shown in Figure 4). The phenotype was fully complemented by addition of the wild type gene in trans. The role of GlpE in oxidative stress adaptation has not previously been investigated, and this observation is the first clear phenotype associated with GlpE in S. Typhimurium. Unexpectedly, the double ΔglpEpspE mutant was not affected (Figure 4). The reason for this remains elusive, but the observation was very reproducible and may indicate that the lack of GlpE is only critical for resistance to H2O2 in the presence of a fully functional PspE.


The putative thiosulfate sulfurtransferases PspE and GlpE contribute to virulence of Salmonella Typhimurium in the mouse model of systemic disease.

Wallrodt I, Jelsbak L, Thorndahl L, Thomsen LE, Lemire S, Olsen JE - PLoS ONE (2013)

Growth of WT (4/74) and pspE and glpE mutated and complemented strains in M9 medium with 10 mM H2O2.Wild type (black), ΔglpE (blue), ΔpspE (green), ΔglpE/ΔpspE (red) and ΔglpE+glpE strains were inoculated to an OD600 value of 0.05, H2O2 was added and growth was followed for 16 hours. Results shown are representative of two biological repeats.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3733917&req=5

pone-0070829-g004: Growth of WT (4/74) and pspE and glpE mutated and complemented strains in M9 medium with 10 mM H2O2.Wild type (black), ΔglpE (blue), ΔpspE (green), ΔglpE/ΔpspE (red) and ΔglpE+glpE strains were inoculated to an OD600 value of 0.05, H2O2 was added and growth was followed for 16 hours. Results shown are representative of two biological repeats.
Mentions: Like nitric oxide, H2O2 also affects the cell through damage of iron- clusters [56], and we found it indicated to investigate the role of GlpE and PspE in the protection against this oxidative stress molecule. We grew our mutants in the presence of 5 mM and 10 mM H2O2 in LB and M9 media and observed that the wild type strain was slightly affected in growth and that the ΔglpE, but not the ΔpspE mutant, was severely affected in growth under this condition in both media (growth in 10 mM H2O2 shown in Figure 4). The phenotype was fully complemented by addition of the wild type gene in trans. The role of GlpE in oxidative stress adaptation has not previously been investigated, and this observation is the first clear phenotype associated with GlpE in S. Typhimurium. Unexpectedly, the double ΔglpEpspE mutant was not affected (Figure 4). The reason for this remains elusive, but the observation was very reproducible and may indicate that the lack of GlpE is only critical for resistance to H2O2 in the presence of a fully functional PspE.

Bottom Line: Since the double mutant, which was the one affected in virulence, was not affected in this assay, we concluded that resistance to oxidative stress and the virulence phenotype was most likely not linked.The two genes did not contribute to nitric oxid stress, to synthesis of essential sulfur containing amino acids, nor to detoxification of cyanide.Currently, the precise mechanism by which they contribute to virulence remains elusive.

View Article: PubMed Central - PubMed

Affiliation: Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.

ABSTRACT
The phage-shock protein PspE and GlpE of the glycerol 3-phosphate regulon of Salmonella enterica serovar Typhimurium are predicted to belong to the class of thiosulfate sulfurtransferases, enzymes that traffic sulfur between molecules. In the present study we demonstrated that the two genes contribute to S. Typhimurium virulence, as a glpE and pspE double deletion strain showed significantly decreased virulence in a mouse model of systemic infection. However, challenge of cultured epithelial cells and macrophages did not reveal any virulence-associated phenotypes. We hypothesized that their contribution to virulence could be in sulfur metabolism or by contributing to resistance to nitric oxide, oxidative stress, or cyanide detoxification. In vitro studies demonstrated that glpE but not pspE was important for resistance to H2O2. Since the double mutant, which was the one affected in virulence, was not affected in this assay, we concluded that resistance to oxidative stress and the virulence phenotype was most likely not linked. The two genes did not contribute to nitric oxid stress, to synthesis of essential sulfur containing amino acids, nor to detoxification of cyanide. Currently, the precise mechanism by which they contribute to virulence remains elusive.

Show MeSH
Related in: MedlinePlus