Project description:The catalase-negative, facultative anaerobe Streptococcus pneumoniae D39 is naturally resistant to hydrogen peroxide (H2O2) produced endogenously by pyruvate oxidase (SpxB). Here, we investigate the adaptive response to endogenously produced H2O2. We show that lactate oxidase, which converts lactate to pyruvate, positively impacts pyruvate flux through SpxB and that ∆lctO mutants produce significantly lower H2O2. In addition, both the SpxB and pyruvate dehydrogenase complex (PDHC) pathways contribute to acetyl-CoA production during aerobic growth, and the pyruvate format lyase (PFL) pathway is the major acetyl-CoA pathway during anaerobic growth. Microarray analysis of the D39 strain cultured under aerobic vs. strict anaerobic conditions show up-regulation of spxB, a rhodanese-like protein (spd0091), tpxD, sodA, piuB, piuD and an Fe-S protein biogenesis operon under H2O2-producing conditions. Proteome profiling of H2O2-induced sulfenylation reveals that sulfenylation levels correlate with cellular H2O2 production, with endogenous sulfenylation of ≈50 proteins. Deletion of tpxD increases cellular sulfenylation 5-fold and has an inhibitory effect on ATP generation. Two major targets of protein sulfenylation are glyceraldehyde-3-phosphate dehydrogenase (GapA) and SpxB itself, but also include pyruvate kinase, LctO, AdhE and acetate kinase (AckA). Sulfenylation of GapA is inhibitory, while the effect on SpxB activity is negligible, consistent with this cell-abundant protein functioning as a “sink” for endogenous H2O2. Strikingly, four enzymes of capsular polysaccharide biosynthesis are sulfenylated, as are enzymes associated nucleotide biosynthesis via ribulose-5-phosphate. We propose that LctO/SpxB-generated H2O2 functions as a signaling molecule to down-regulate capsule production and drive altered flux through sugar utilization pathways.
Project description:Comparison of Streptococcus pneumoniae D39 argR1 mutant compared to D39 wild type in CDM with 10 mM arginine to define the regulon of the ArgR1 regulator under this condition. Details described in Kloosterman TG and Kuipers OP. ArgR1 and AhrC Mediate Arginine-Dependent Regulation of Arginine Acquisition- and Virulence Genes in the Human Pathogen Streptococcus pneumoniae. JBC 2011
Project description:Comparison of Streptococcus pneumoniae D39 ahrC mutant compared to D39 wild type in CDM with 10 mM arginine to define the regulon of the AhrC regulator under this condition. Details described in Kloosterman TG and Kuipers OP. ArgR1 and AhrC Mediate Arginine-Dependent Regulation of Arginine Acquisition- and Virulence Genes in the Human Pathogen Streptococcus pneumoniae. JBC 2011
Project description:Comparison of Streptococcus pneumoniae D39 argR1-ahrC mutant compared to D39 wild type in CDM with 10 mM arginine to define the regulons of the ArgR1 and AhrC regulators under this condition. Details described in Kloosterman TG and Kuipers OP. ArgR1 and AhrC Mediate Arginine-Dependent Regulation of Arginine Acquisition- and Virulence Genes in the Human Pathogen Streptococcus pneumoniae. JBC 2011
Project description:Comparison of Streptococcus pneumoniae D39 argR1 mutant compared to D39 wild type in CDM with 10 mM arginine to define the regulon of the ArgR1 regulator under this condition. Details described in Kloosterman TG and Kuipers OP. ArgR1 and AhrC Mediate Arginine-Dependent Regulation of Arginine Acquisition- and Virulence Genes in the Human Pathogen Streptococcus pneumoniae. JBC 2011 One condition design comparison of two strains including a dye swap
Project description:Comparison of Streptococcus pneumoniae D39 ahrC mutant compared to D39 wild type in CDM with 10 mM arginine to define the regulon of the AhrC regulator under this condition. Details described in Kloosterman TG and Kuipers OP. ArgR1 and AhrC Mediate Arginine-Dependent Regulation of Arginine Acquisition- and Virulence Genes in the Human Pathogen Streptococcus pneumoniae. JBC 2011 One condition design comparision of two strains including a dye swap
Project description:Comparison of Streptococcus pneumoniae D39 wild-type grown in CDM+10 mM arginine compared to D39 wild type grown in CDM + 0.05 mM arginine to define the genome-wide transcriptional response to arginine. Details described in Kloosterman TG and Kuipers OP. ArgR1 and AhrC Mediate Arginine-Dependent Regulation of Arginine Acquisition- and Virulence Genes in the Human Pathogen Streptococcus pneumoniae. JBC 2011
Project description:Comparison of Streptococcus pneumoniae D39 argR1-ahrC mutant compared to D39 wild type in CDM with 10 mM arginine to define the regulons of the ArgR1 and AhrC regulators under this condition. Details described in Kloosterman TG and Kuipers OP. ArgR1 and AhrC Mediate Arginine-Dependent Regulation of Arginine Acquisition- and Virulence Genes in the Human Pathogen Streptococcus pneumoniae. JBC 2011 One condition design comparison of two strains including a dye swap
Project description:Acetyl phosphate (AcP) is a small-molecule metabolite that can act as a phosphoryl group donor for response regulators of two-component regulatory systems (TCSs). Streptococcus pneumoniae (pneumococcus) synthesizes AcP by the conventional pathway involving the phosphotransacetylase and acetate kinase enzymes encoded by the pta and ackA genes, respectively. In addition, pneumococcus synthesizes copious amounts of AcP and hydrogen peroxide (H2O2) by the pyruvate oxidase enzyme encoded by spxB. To access possible roles of AcP in pneumococcal TCS regulation and metabolism, we constructed combinations of spxB, pta, and ackA mutants and determined their ATP, AcP, and H2O2 production. Epistasis and microarray experiments were consistent with a role for the AcP biosynthetic pathway in basal-level phosphorylation of WalRSpn and possibly other response regulators involved in sensing cell wall status. However, this basal phosphorylation likely does not play an active physiological role in sensing in S. pneumoniae.
Project description:A two-hit model of adenoviral vector delivery of active transforming growth factor-β (TGFb) 1 to induce fibrosis in mice in conjunction with treatment of the mice with purified pneumolysin from Streptococcus pneumoniae was applied to characterize the role of this virulence factor on fibrosis perpetuation in mice The study was supported by a BMBF grant for the German Center for Lung Research, partner site BREATH (Biomedical Research in Endstage and Obstructive Lung Disease Hannover)
