Streptococcus pneumoniae
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA93063 | ENA |
REPOSITORIES: ENA
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Project description:Streptococcus pneumoniae is opportunistic bacteria cause’s acute otitis media (AOM) in children. It colonizes the nasopharynx in the form of biofilms, and these biofilms act as reservoir, and are vital for pneumococcal infections. The pneumococcal biofilms are regulated by LuxS/AI-2 media quorum sensing. In this study, we confirmed the role of LuxS/AI-2 for in vitro formation of biofilms, assessed the effects of the absence of LuxS/AI-2 signaling, for pneumococcal middle ear infection and identified global genes regulated by LuxS/AI-2 during formation of pneumococcal biofilms. In the cDNA-microarray analysis, 117 genes were differentially expressed in D39 luxS mutant when compared with D39 wild type. Among the 66 genes encoding putative proteins and previously characterized proteins, 60 were significantly down-regulated and 6 were significantly up-regulated. The functional annotation revealed that genes involve in DNA replication and repair, ATP synthesis, capsule biosynthesis, cell division and cell cycle, signal transduction, transcription regulation, competence, virulence, and carbohydrate metabolism were down-regulated in the absence of LuxS/AI-2.
2018-05-17 | GSE109347 | GEO
Project description:Investigation of differentially regulated gene in deletion of TprA2 compared to the wild-type. TprA2 is a transcriptional regulator. Its characterization is described in Kadam et al 2017 Promiscuous signaling by a regulatory system unique to the pandemic PMEN1 pneumococcal lineage. PLoS Pathog. 2017 May; 13(5): e1006339.
2017-11-10 | GSE106753 | GEO
Project description:RNases perform indispensable functions in regulating gene expression in many bacterial pathogens by processing and/or degrading RNAs. Despite the pivotal role of RNases in regulating bacterial virulence factors, the functions of RNases have not yet been studied in the major human respiratory pathogen Streptococcus pneumoniae (pneumococcus). Here, we sought to determine the impact of two conserved RNases, the endoribonuclease RNase Y and exoribonuclease polynucleotide phosphorylase (PNPase), on the physiology and virulence of S. pneumoniae serotype 2 strain D39. We report that RNase Y and PNPase are essential for pneumococcal pathogenesis as both deletion mutants showed strong attenuation of virulence in murine models of invasive pneumonia. Genome-wide transcriptomic analysis revealed that nearly 200 mRNA transcripts were significantly up-regulated, whereas the abundance of several pneumococcal sRNAs, including the Ccn (CiaR Controlled Noncoding RNA) sRNAs, were altered in the ∆rny mutant relative to the wild-type strain. Additionally, lack of RNase Y resulted in pleiotropic phenotypes that included defects in pneumococcal cell morphology and growth in vitro. In contrast, Dpnp mutants showed no growth defect in vitro, but differentially expressed a total of 40 transcripts including the tryptophan biosynthesis operon genes and numerous 5’-cis-acting regulatory RNAs, a majority of which were previously shown to impact pneumococcal disease progression in mice using the serotype 4 strain TIGR4. Altogether our data suggest that RNase Y exerts a global impact on pneumococcal physiology, while PNPase-mediates virulence phenotypes, likely through sRNA regulation.
2021-09-02 | GSE173392 | GEO
Project description:Cis- and trans-Regulation of Pneumococcal spxB
| PRJNA98413 | ENA
Project description:We were interested in determining if the LuxS signaling system contributed to the regulation of pneumococcal genes. To accomplish this, we compared the in vitro transcriptional profiles over time of S. pneumoniae D39, a serotype 2 strain of pneumococcus, with that of an isogenic deletion mutant, (delta)luxS, using a spotted S. pneumoniae- specific DNA microarray. For in vitro time course experiments, broth cultures of D39 and (delta)luxS were grown to low density (optical densities between ~0.01- 0.02), the cells were collected by centrifugation, washed 1x with sterile PBS, back diluted to ~3x105CFU/ ml into fresh broth, and immediately incubated at 37oC in a 5% CO2 chamber for 45 minutes. At this point, the first sample was collected. Subsequently, growth was monitored for approximately 8 generations by measuring both the optical density (OD600) and determining viable counts every 30 to 45 minutes. At these points samples were also harvested by centrifugation for RNA isolation and stored at -80oC until processing. For microarray probe synthesis, experimental samples were generated using 0.5ug total bacterial RNA isolated from either D39 or (delta)luxS strains at the various time points throughout the growth curve. These RNAs were used as templates for reverse transcription, and the resulting cDNAs were labelled with Cy5. The reference sample for each time course was generated from the D39 time zero RNA. Subsequent to reverse transcription, the resulting cDNAs were labelled with Cy3. The probes were mixed in hybridization buffer, heated to 99oC for at least 2 minutes, centrifuged briefly, and applied to the microarray. Hybridizations were carried out at 60oC for at least 24 hours.
2005-07-21 | E-SMDB-2173 | biostudies-arrayexpress
Project description:The primary mechanism by which pneumococcal capsular polysaccharide-based vaccines are believed to mediate protection is by induction of serotype-specific opsonic antibodies that facilitate bacterial killing by phagocytes (opsonophagocytosis). However, antibodies that are protective against experimental pneumococcal pneumonia in mice but do not promote opsonophagocytic killing in vitro have also been identified 1-3. Such non-opsonic antibodies are associated with bacterial clearance in vivo, but the mechanism by which this occurs is unknown. In this letter, we demonstrate that a protective, non-opsonic serotype 3 pneumococcal capsular polysaccharide-specific monoclonal antibody (MAb) enhances quorum sensing, which results in competence induction and fratricide of serotype 3 pneumococcus. Gene expression profile analysis revealed that the MAb together with the pneumococcal autoinducer, competence stimulating peptide 2 (CSP2), augments differential expression of competence (com) related bacteriocin-like peptide (blp) genes that are known to be involved in pneumococcal fratricide. Taken together, these findings reveal a previously unsuspected mechanism of antibody action, namely, enhancement of quorum sensing and bacterial fratricide. Given that this activity does not require phagocytes, antibodies that function accordingly may hold promise as adjuncts to current vaccines or as desired products of next generation pneumococcal vaccines.
2011-03-01 | GSE27258 | GEO
Project description:Treatment of pneumococcal infections is limited by antibiotic resistance and exacerbation of disease by bacterial lysis releasing pneumolysin toxin and other inflammatory factors. We identified a novel peptide in the Klebsiella pneumoniae secretome, which enters Streptococcus pneumoniae via its AmiA-AliA/AliB permease. Subsequent downregulation of genes for amino acid biosynthesis and peptide uptake was associated with reduction of pneumococcal growth in defined medium and human cerebrospinal fluid, irregular cell shape, decreased chain length and decreased genetic transformation. The bacteriostatic effect was specific to S. pneumoniae and Streptococcus pseudopneumoniae with no effect on Streptococcus mitis, Haemophilus influenzae, Staphylococcus aureus or K. pneumoniae. Peptide sequence and length were crucial to growth suppression. The peptide reduced pneumococcal adherence to primary human airway epithelial cell cultures and colonization of rat nasopharynx, without toxicity. We also analysed the effect of peptide on the proteome of S. pneumoniae. We found alteration of the proteome by the peptide with some proteins turned on or off in line with the transcriptomic changes. We therefore identified a peptide with potential as a therapeutic for pneumococcal diseases suppressing growth of multiple clinical isolates, including antibiotic resistant strains, while avoiding bacterial lysis and dysbiosis.
2024-04-08 | PXD050408 | Pride
Project description:Post-transcriptional gene regulation often involves RNA-binding proteins that modulate mRNA translation and/or stability either directly through protein-RNA interactions or indirectly by facilitating the annealing of small regulatory RNAs (sRNAs). The human pathogen Streptococcus pneumoniae D39 (pneumococcus) does not encode in its genome any homologs to RNA-binding proteins known to be involved in promoting sRNA stability and function, such as Hfq or ProQ, even though it contains genes for at least 112 sRNAs. Instead, the pneumococcal genome contains genes for at least six S1 RNA-binding domain proteins, which includes ribosomal protein S1 (rpsA), polynucleotide phosphorylase (pnpA), RNase R (rnr), and three proteins of unknown function. Here, we characterize the function of one of these conserved, yet uncharacterized S1-domain proteins, SPD_1366, which we have renamed CvfD (Conserved virulence factor D), since loss of this protein results in a attenuation of virulence in a murine pneumonia model. We also report that deletion of cvfD impacts expression of 144 transcripts including the pst1 operon, encoding the phosphate transport system 1 in S. pneumoniae. We further show that CvfD post-transcriptionally regulates the PhoU2 master regulator of the pneumococcal dual phosphate transport system by binding phoU2 mRNA and impacting translation. CvfD not only controls expression of phosphate transporter genes, but also functions as a global regulator impacting cold sensitivity and the expression of sRNAs and genes involved in diverse cellular functions, including manganese uptake and zinc efflux. Together, our data suggest that CvfD exerts a broad impact on pneumococcal physiology and virulence via post-transcriptional gene regulation.
2020-07-01 | GSE148867 | GEO
Project description:Genome-wide screens have discovered a large set of essential genes in the human pathogen Streptococcus pneumoniae. However, the function of many essential genes is still unknown, hampering vaccine and drug development programs. Based on results from transposon-sequencing (Tn-Seq), we refined the list of essential genes in S. pneumoniae serotype 2 strain D39. Next, we created a knockdown library targeting all 391 potentially essential genes using CRISPR interference (CRISPRi). Using high-content microscopy screening, we searched for essential genes of unknown function with clear phenotypes in cell morphology upon CRISPRi-based depletion. We identified SPD1416 and SPD1417 (named to MurT and GatD, respectively) as essential peptidoglycan synthesis proteins and we show that SPD1198 and SPD1197 (named to TarP and TarQ, respectively) are responsible for the polymerization of teichoic acid (TA) precursors. This knowledge enabled us to reconstruct the unique pneumococcal TA biosynthetic pathway. Our CRISPRi library provides a valuable tool for characterization of pneumococcal genes and pathways and revealed several promising antibiotic targets. This RNA-Seq dataset is aimed to show that induction of the CRISPRi system very selectively represses its target gene, firefly luciferase, without other observable transcriptional effects.
2017-03-03 | GSE89763 | GEO
Project description:Segregation of replicated chromosomes during cell division is an essential process in all organisms. Chromosome segregation is promoted by the action of the DNA-binding ParB protein in the rod-shaped model bacterium Bacillus subtilis. How oval shaped bacteria, such as the human pathogen Streptococcus pneumoniae, efficiently segregate their chromosomes is poorly understood. Here, we show that the pneumococcal homolog of ParB is enriched at four centromere-like DNA sequences (parS sites) that are present near the origin of replication.
2011-06-11 | GSE26839 | GEO