Streptococcus pneumoniae
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ABSTRACT:
PROVIDER: PRJNA102099 | ENA |
REPOSITORIES: ENA
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Project description:Invasive pneumococcal disease is preceded by asymptomatic colonization of the human nasopharynx by Streptococcus pneumoniae. Progression from colonization to invasion is a watershed in the host-pathogen interaction, and exposes the pneumococcus to markedly different microenvironments. This in turn, requires alterations in gene expression profile to adapt to the new niche. One apparent adaptive mechanism is reversible phase variation between “transparent” and “opaque” colony opacity phenotypes. Transparent phase variants colonize the nasopharynx more efficiently than opaque variants of the same strain, while opaque variants exhibit higher systemic virulence. Previous studies have reported quantitative differences in surface components such as the capsule, teichoic acid and certain surface proteins between the two phenotypes, but the underlying regulatory mechanism is not understood. In the present study, we found no differences in expression of key surface proteins between opaque and transparent variants of S. pneumoniae strain D39, but opaque cells produced five-fold more capsular polysaccharide. Subsequent microarray and real-time RT-PCR analysis showed no differences in capsule gene expression, but several genes involved in uridine monophosphate (UMP) biosynthesis were up-regulated in the opaque phenotype. This correlated with significant increases in the intracellular concentrations of both UMP and UDP-glucose, which are essential precursors for capsule biosynthesis. Our data suggest a novel mechanism for pneumococcal capsule regulation, in which rate-limiting precursor pathways are modulated rather than the capsule biosynthetic genes themselves. Keywords: Phase variants
2007-08-17 | GSE8797 | GEO
Project description:Transcriptional profiling of primary monocyte derived macrophages (MDMs) comparing control untreated MDMs with MDMs exposed with Serotype 2 Streptococcus pneumoniae (D39) strain (MOI 10) for 3 hours) Three-condition experiment, control MDMs vs. D39 infected MDMs vs Stop infected MDMs. Biological replicates: 3 control replicates, 3 infected D39 replicates and 3 infected penumolysin deficient (STOP) MOI 10.
2021-03-01 | E-MTAB-9055 | biostudies-arrayexpress
Project description:Streptococcus pneumoniae (pneumococcus) is a major human respiratory pathogen and the leading cause of bacterial pneumonia worldwide. Small regulatory RNAs (sRNAs), which often act by post-transcriptionally regulating gene expression, have been shown to be crucial for the virulence of S. pneumoniae and other bacterial pathogens. Over 170 putative sRNAs have been identified in S. pneumoniae TIGR4 strain (serotype 4) through transcriptomic studies, and a subset of these sRNAs have been further implicated in regulating pneumococcal pathogenesis. However, there was little overlap in the sRNAs identified among these studies, which indicated that the approaches used for sRNA identification were not sufficiently sensitive and robust and that there were likely many more undiscovered sRNAs encoded in the S. pneumoniae genome. Here, we sought to comprehensively identify sRNAs in Avery's virulent S. pneumoniae strain D39 using two independent RNA-seq based approaches. We developed an unbiased method for identifying novel sRNAs from bacterial RNA-seq data and have further tested the specificity of our analysis program towards identifying sRNAs encoded by both strains D39 and TIGR4. Interestingly, the genes for 15% of the putative sRNAs identified in strain TIGR4 including ones previously implicated in virulence were not present in strain D39 genome suggesting that the differences in sRNA repertoires between these two serotypes may contribute to their strain-specific virulence properties. Finally, this study has identified 67 new sRNA candidates in strain D39, 28 out of which have been further validated, raising the total number of sRNAs that have been identified in strain D39 to 112.
2019-03-11 | GSE123437 | GEO
Project description:Streptococcus pneumoniae (pneumococcus) is a major human respiratory pathogen and a leading cause of bacterial pneumonia worldwide. Small regulatory RNAs (sRNAs), which often act by post-transcriptionally regulating gene expression, have been shown to be crucial for the virulence of S. pneumoniae and other bacterial pathogens. Over 170 putative sRNAs have been identified in S. pneumoniae TIGR4 strain (serotype 4) through transcriptomic studies, and a subset of these sRNAs have been further implicated in regulating pneumococcal pathogenesis. However, there is little overlap in the sRNAs identified among these studies, which indicates that the approaches used for sRNA identification were not sufficiently sensitive and robust and that there are likely many more undiscovered sRNAs encoded in the S. pneumoniae genome. Here, we sought to comprehensively identify sRNAs in Avery's virulent S. pneumoniae strain D39 using two independent RNA-seq based approaches. We developed an unbiased method for identifying novel sRNAs from bacterial RNA-seq data and have further tested the specificity of our analysis program towards identifying sRNAs encoded by both strains D39 and TIGR4. Interestingly, the genes for 15% of the putative sRNAs identified in strain TIGR4 including ones previously implicated in virulence are not present in strain D39 genome suggesting that the differences in sRNA repertoires between these two serotypes may contribute to their strain-specific virulence properties. Finally, this study has identified 67 new sRNA candidates in strain D39, 28 out of which have been further validated, raising the total number of sRNAs that have been identified in strain D39 to 112.
2019-05-13 | GSE124170 | GEO
Project description:This SuperSeries is composed of the following subset Series: GSE31815: ccpA mutant compared to D39 wild-type in Streptococcus pneumoniae in CDM + Glucose at MID-log growth phase GSE31816: ccpA mutant compared to D39 wild-type in Streptococcus pneumoniae in CDM + GLucose at transition-phase of growth (TS) GSE31817: ccpA mutant compared to D39 wild-type in Streptococcus pneumoniae in CDM + Galactose at MID-log growth phase GSE31818: ccpA mutant compared to D39 wild-type in Streptococcus pneumoniae in CDM + galactose at transition-phase of growth (TS) Refer to individual Series
2011-09-30 | E-GEOD-31819 | biostudies-arrayexpress
Project description:Three Microarray comparisons have been preformed in this study. 1- Transcriptome comparison of the Streptococcus pneumoniae D39 wild type grown in M17 medium + 0.5 % (w/v) NAGa (NAGaM17) to M17 medium + 0.5 % (w/v) glucose (GM17) (GSM2372597 and GSM2372598). 2- Transcriptome comparison of the Streptococcus pneumoniae D39 ΔagaR to D39 wild type grown in M17 medium + 0.5 % (w/v) glucose (GM17) (GSM2372599 and GSM2372600). 3- Transcriptome comparison of the Streptococcus pneumoniae D39 ΔccpA to D39 wild type grown in M17 medium + 0.5 % (w/v) NAGa (NAGaM17) (GSM2290636 and GSM2290637).
2016-11-02 | GSE86008 | GEO
Project description:Transcriptome comparison of the Streptococcus pneumoniae D39 ΔnaiR to D39 wild type grown in CDM
2017-02-24 | GSE94511 | GEO
Project description:Transcriptome comparison of the Streptococcus pneumoniae D39 wild-type grown in CDM with 0mM to 0.05 mM copper.
2011-07-10 | GSE30413 | GEO
Project description:By comparing the transcriptome of Streptococcus pneumoniae wild-type D39 (serotype 2) to an isogenic strain overexpressing the response regulator of Two-Component System 7 (SPD_0158), we identified the regulon of the two-component system. In total 20 and 24 genes were considered up- and downregulated, respectively. 11 of the upregulated genes encode for proteins involved in host-glycan metabolism, while 7 encode proteins involved in carbohydrate metabolism. Most downregulated genes encode competence genes, but later experiments proved this was likely due to an atefact of overexpression. The remaining genes encode genes with other functions.
2019-06-15 | GSE132733 | GEO
Project description:spxB-encoded pyruvate oxidase is a major virulence factor of Streptococcus pneumoniae. During aerobic growth, SpxB synthesizes H2O2 and acetyl phosphate, which play roles in metabolism, signaling, and oxidative stress. We report here the first cis- and trans-acting regulatory elements for spxB transcription. These elements were identified in a genetic screen for spontaneous mutations that caused colonies of strain D39 to change from a semi-transparent to an opaque appearance. Six of the seven opaque colonies recovered (frequency 3x10-5) were impaired for SpxB function or expression. Two mutations changed amino acids in SpxB likely required for cofactor or subunit binding. One mutation defined a cis-acting adjacent direct repeat required for optimal spxB transcription. The other three spontaneous mutations created the same frameshift near the start of the trans-acting spxR regulatory gene. The SpxR protein contains helix-turn-helix, CBS, and HotDog domains implicated in binding DNA, adenosyl compounds, and CoA-containing compounds, respectively, and suggest that SpxR positively regulates spxB transcription in response to energy and metabolic state. Finally, microarray analyses of a spxR mutant demonstrated that SpxR positively regulates the strH exoglycosidase gene, which like spxB, has been implicated in colonization. Keywords: bacterial genetic modification
2008-01-04 | GSE9284 | GEO