Transcriptome analysis of wt Pilus-1 expressing Streptococcus pneumoniae strains
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ABSTRACT:
ORGANISM(S): Streptococcus pneumoniae
SUBMITTER: Alessandro Muzzi
PROVIDER: E-TABM-1154 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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2010-05-15 | E-GEOD-14750 | biostudies-arrayexpress
Project description:Streptococcus pneumoniae D39 AdcR (adhesion competence repressor) is the first metal-sensing member of the MarR (multiple antibiotic resistance repressor) family to be characterized. Expression profiling of a âadcR strain grown in liquid culture under microaerobic conditions revealed that transcript amounts for 13 genes were up-regulated relative to the wild-type strain, among them adcR, adcCBA, encoding a high affinity ABC uptake system for zinc, and genes encoding cell-surface zinc-binding pneumococcal histidine triad (pht) and adcII (lmb, laminin binding) proteins. Down-regulated transcripts included those encoding two putative zinc-containing alcohol dehydrogenases. Bacterial strains were grown exponentially in rich (BHI) media at 37C and an atmosphere of 5% CO2 to OD620~0.2, and were processed as described in the related Sample records. Samples were collected from three independent biological replicates and included one dye swap. Data were normalized using the Lowess (block) method without background subtraction. Changes in relative transcript amounts of positive or negative 2-fold with Bayesian P value of <0.001 were considered significant, and were included as supplementary material for the accompanying manuscript (The metalloregulatory site in Streptococcus pneumoniae AdcR, a zinc-activated MarR-family repressor; Reyes-Caballero, H. et al, manuscript in preparation).
2010-10-01 | E-GEOD-21506 | biostudies-arrayexpress
Project description:For Streptococcus pneumoniae, biofilms have been suggested to promote long-term colonization of the nasopharynx and contribute to the pathology of recurrent middle ear infections. To date numerous studies have investigated the contribution of specific genetic determinants for the development of pneumococcal biofilms, however, studies examining the global changes that occur during biofilm development and how they contribute to disease are lacking. Using Scanning and Transmission electron microscopy we examined development of a mature pneumococcal biofilm in a continuous flow through reactor. We determined that a mature biofilm is formed in discrete stages, is marked by the formation of complex 3-dimensional structures, and is primarily composed of dead pneumococci. Using genomic microarrays we determined that pneumococci in mature biofilms down regulate genes involved in protein synthesis, energy production, metabolism, capsular polysaccharide production, and virulence. We confirmed these changes by testing bacterial resistance to antimicrobials, measuring capsule production by ELSIA, and immunoblotting for pneumolysin production. We determined that biofilm pneumococci are hyper-adhesive, binding to cell lines at levels 9 to 11-fold greater than planktonic counterparts. Using Western blot and ELISA, we determined that biofilm bacteria produce greater amounts of the adhesins PsrP, CbpA, and surface exposed phosphorylcholine. We subsequently determined that the hyper-adhesive phenotype was in part due to selection of the transparent phase variant during biofilm growth. Intranasal, intratracheal and intraperitoneal challenge of mice with biofilm and planktonic pneumococci determined that biofilm bacteria were highly attenuated for invasive disease but not nasopharyngeal colonization. Immunization of mice with ethanol-killed biofilm pneumococci of serotype 4 conferred protection against challenge with same isolate but not a serotype 3. ELISA for reactive IgG levels subsequently determined that biofilm pneumococci do not provide high levels of cross-reactive protein antigens. Together these studies suggest that biofilms do not directly contribute to disease but instead confer a protected mode of growth for the pneumococcus. Pneumococcal biofilms compared to planktonic control at 4, 12, 24, 48 hours. 3 biological replicates each of 4 and 12 hour time points, and 2 biological replicates each of 24 and 48 hour time points. Flip dye (technical replicates) performed for 4, 12, and 24 hour time points; no technical replicate performed for 48 hour time point due to limiting material. Ratios were determined by averaging across technical and biological replicates. The following hybridizations made up each biological replicate: 14090167.tav.annot and 14090190.tav.annot (4hr biol rep 1); 14090169.tav.annot and 14090176.tav.annot (4hr biol rep 2); 14090192.tav.annot and 14090188.tav.annot (4hr biol rep 3); 14087688.tav.annot and 14090180.tav.annot (12hr biol rep 1); 14090185.tav.annot and 14090168.tav.annot (12hr biol rep 2); 14090191.tav.annot and 14090174.tav.annot (12hr biol rep 3); 14090170.tav.annot and 14090175.tav.annot (24hr biol rep 2); 14090193.tav.annot and 14087687.tav.annot (24hr biol rep 3); 14090181.tav.annot (48hr biol rep 1); 14090187.tav.annot (48hr biol rep 2)
2013-04-01 | E-GEOD-26976 | biostudies-arrayexpress
Project description:Copper is essential for both innate and adaptive immune function and copper resistance has emerged as an important determinant of virulence of microbial pathogens. In the human pathogen Streptococcus pneumoniae (Spn), cytoplasmic copper resistance is mediated by an operon encoding the copper-responsive repressor CopY, CupA, of unknown function, and CopA, a copper effluxing P1B-type ATPase. We show that CupA is a novel cell membrane-anchored Cu(I) chaperone for CopA, and that a Cu(I)-binding competent, membrane-localized CupA, like CopA, is obligatory for copper resistance. Bacteria were grown statically in Brain Heart Infusion media (Bacto BHI, Becton Dickinson) at 37C in an atmosphere of 5% CO2 to a culture density of OD620~0.2 and were processed as described in the related Sample record. Strain IU1781 (D39 rpsL1) served as the reference for the strain comparison. The experiment was repeated one time, and results are consistent with those observed by Shafeeq et al (Mol Microbiol. 2011). Data normalization was performed using the BioArray Software Environment (BASE 1.2; Saal et al, Genome Biol. 2002) using the Lowess (subgrid) method. Median spot intensities were normalized without background subtraction and used to calculate expression ratios. The cut-off for statistical significance of differential expression was set at an average up or down fold change of at least 1.8 fold.
2013-05-24 | E-GEOD-39176 | biostudies-arrayexpress
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2012-10-10 | E-GEOD-25448 | biostudies-arrayexpress
Project description:PsrA and PsrB were found to repress Type III secretion (T3S) when provided in multicopy. Total RNA was extracted at late exponential phase in T3S permissive media (MEM-HEPES). Transcriptional profiles were expressed relative to the vector control (pGEM). Dual colour design. Cy5 labelled cDNA from TUV93-0 pPsrA or pPsrB cultures were hybridised against TUV93-0 pGEM Cy3 labelled cDNA. Data were normalised using the Genespring GX 7.3.1 analysis package.
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