Abstract:Introduction
Manganese is important for the endocarditis pathogen Streptococcus sanguinis. Little is known about why manganese is required for virulence or how it impacts the metabolome of streptococci.
Objectives
We applied untargeted metabolomics to cells and media to understand temporal changes resulting from manganese depletion.
Methods
EDTA was added to a S. sanguinis manganese-transporter mutant … Show more
“…The most highly enriched pathway for the ΔssaACB mutant was the "Porphyrin/ Chlorophyll" pathway but upon examination, these genes encode the cobalamin biosynthetic enzymes (Table S2), which were also significantly downregulated in our recent study of manganese depletion . Many of the pathways highlighted by this analysis, such as carbon metabolism and amino acid metabolism, were also affected by manganese reduction in our recent transcriptomic and metabolomic studies Puccio, Misra, et al, 2021).…”
Section: Rna-seq Analysis Of Fermentor-grown Sk36 Wt and δSsaacb Cell...mentioning
confidence: 58%
“…We recently reported that manganese depletion led to induction of carbon catabolite repression (CCR) in S. sanguinis (Puccio et al., 2020; Puccio, Misra, et al., 2021). Given that both addition of acid and EDTA (Puccio, Misra, et al., 2021) led to reduced manganese levels in the fermentor (Figure 4), we hypothesize that the impact on glycolysis is similar to what we observed in our previous study.…”
Section: Discussionmentioning
confidence: 99%
“…We recently reported that manganese depletion led to induction of carbon catabolite repression (CCR) in S. sanguinis (Puccio et al., 2020; Puccio, Misra, et al., 2021). Given that both addition of acid and EDTA (Puccio, Misra, et al., 2021) led to reduced manganese levels in the fermentor (Figure 4), we hypothesize that the impact on glycolysis is similar to what we observed in our previous study. Additionally, expression of genes encoding glycolytic enzymes responded similarly in both studies (Table ), indicating that the regulatory mechanisms controlling the expression of these genes may have a manganese‐related aspect.…”
Section: Discussionmentioning
confidence: 99%
“…Additionally, expression of genes encoding glycolytic enzymes responded similarly in both studies (Table ), indicating that the regulatory mechanisms controlling the expression of these genes may have a manganese‐related aspect. Thus, we hypothesize that there is likely an accumulation of fructose‐1,6‐bisphosphate (FBP) occurring in cells growing at reduced pH due to reduced activity of Fba, Fbp, or both enzymes (Puccio, Misra, et al., 2021). This may be the cause behind the changes in expression we observed in the CcpA regulon (Table ).…”
Streptococcus sanguinis is an oral commensal and an etiological agent of infective endocarditis. Previous studies have identified the SsaACB manganese transporter as essential for endocarditis virulence; however, the significance of SsaACB in the oral environment has never been examined. Here we report that a ΔssaACB deletion mutant of strain SK36 exhibits reduced growth and manganese uptake under acidic conditions. Further studies revealed that these deficits resulted from the decreased activity of TmpA, shown in the accompanying paper to function as a ZIP‐family manganese transporter. Transcriptomic analysis of fermentor‐grown cultures of SK36 WT and ΔssaACB strains identified pH‐dependent changes related to carbon catabolite repression in both strains, though their magnitude was generally greater in the mutant. In strain VMC66, which possesses a MntH transporter, loss of SsaACB did not significantly alter growth or cellular manganese levels under the same conditions. Interestingly, there were only modest differences between SK36 and its ΔssaACB mutant in competition with Streptococcus mutans in vitro and in a murine oral colonization model. Our results suggest that the heterogeneity of the oral environment may provide a rationale for the variety of manganese transporters found in S. sanguinis.
“…The most highly enriched pathway for the ΔssaACB mutant was the "Porphyrin/ Chlorophyll" pathway but upon examination, these genes encode the cobalamin biosynthetic enzymes (Table S2), which were also significantly downregulated in our recent study of manganese depletion . Many of the pathways highlighted by this analysis, such as carbon metabolism and amino acid metabolism, were also affected by manganese reduction in our recent transcriptomic and metabolomic studies Puccio, Misra, et al, 2021).…”
Section: Rna-seq Analysis Of Fermentor-grown Sk36 Wt and δSsaacb Cell...mentioning
confidence: 58%
“…We recently reported that manganese depletion led to induction of carbon catabolite repression (CCR) in S. sanguinis (Puccio et al., 2020; Puccio, Misra, et al., 2021). Given that both addition of acid and EDTA (Puccio, Misra, et al., 2021) led to reduced manganese levels in the fermentor (Figure 4), we hypothesize that the impact on glycolysis is similar to what we observed in our previous study.…”
Section: Discussionmentioning
confidence: 99%
“…We recently reported that manganese depletion led to induction of carbon catabolite repression (CCR) in S. sanguinis (Puccio et al., 2020; Puccio, Misra, et al., 2021). Given that both addition of acid and EDTA (Puccio, Misra, et al., 2021) led to reduced manganese levels in the fermentor (Figure 4), we hypothesize that the impact on glycolysis is similar to what we observed in our previous study. Additionally, expression of genes encoding glycolytic enzymes responded similarly in both studies (Table ), indicating that the regulatory mechanisms controlling the expression of these genes may have a manganese‐related aspect.…”
Section: Discussionmentioning
confidence: 99%
“…Additionally, expression of genes encoding glycolytic enzymes responded similarly in both studies (Table ), indicating that the regulatory mechanisms controlling the expression of these genes may have a manganese‐related aspect. Thus, we hypothesize that there is likely an accumulation of fructose‐1,6‐bisphosphate (FBP) occurring in cells growing at reduced pH due to reduced activity of Fba, Fbp, or both enzymes (Puccio, Misra, et al., 2021). This may be the cause behind the changes in expression we observed in the CcpA regulon (Table ).…”
Streptococcus sanguinis is an oral commensal and an etiological agent of infective endocarditis. Previous studies have identified the SsaACB manganese transporter as essential for endocarditis virulence; however, the significance of SsaACB in the oral environment has never been examined. Here we report that a ΔssaACB deletion mutant of strain SK36 exhibits reduced growth and manganese uptake under acidic conditions. Further studies revealed that these deficits resulted from the decreased activity of TmpA, shown in the accompanying paper to function as a ZIP‐family manganese transporter. Transcriptomic analysis of fermentor‐grown cultures of SK36 WT and ΔssaACB strains identified pH‐dependent changes related to carbon catabolite repression in both strains, though their magnitude was generally greater in the mutant. In strain VMC66, which possesses a MntH transporter, loss of SsaACB did not significantly alter growth or cellular manganese levels under the same conditions. Interestingly, there were only modest differences between SK36 and its ΔssaACB mutant in competition with Streptococcus mutans in vitro and in a murine oral colonization model. Our results suggest that the heterogeneity of the oral environment may provide a rationale for the variety of manganese transporters found in S. sanguinis.
“…In fact, the chain length of ∆ gloA2 SM / fruI was considerably shorter than that of the wild type, a result echoed what was reported previously in ∆ fruI SM background [ 35 ]. Regarding the phenotype of ∆ gloA2 SM when growing on BMGS and BHI, it has been demonstrated that sucrose catabolism by S. mutans often leads to release of free fructose; BHI medium contains a small amount of fructose contaminant [ 38 , 39 ]. Figure 6.…”
Objectives
To analyze contributions to microbial ecology of Reactive Electrophile Species (RES), including methylglyoxal, generated during glycolysis.
Methods
Genetic analyses were performed on the glyoxalase pathway in Streptococcus mutans (SM) and Streptococcus sanguinis (SS), followed by phenotypic assays and transcription analysis.
Results
Deleting glyoxalase I (lguL) reduced RES tolerance to a far greater extent in SM than in SS, decreasing the competitiveness of SM against SS. Although SM displays a greater RES tolerance than SS, lguL-null mutants of either species showed similar tolerance; a finding consistent with the ability of methylglyoxal to induce the expression of lguL in SM, but not in SS. A novel paralogue of lguL (named gloA2) was identified in most streptococci. SM mutant ∆gloA2SM showed little change in methylglyoxal tolerance yet a significant growth defect and increased autolysis on fructose, a phenotype reversed by the addition of glutathione, or by the deletion of a fructose: phosphotransferase system (PTS) that generates fructose-1-phosphate (F-1-P).
Conclusions
Fructose contributes to RES generation in a PTS-specific manner, and GloA2 may be required to degrade certain RES derived from F-1-P. This study reveals the critical roles of RES in fitness and interbacterial competition and the effects of PTS in modulating RES metabolism.
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