Project description:The human pathogen Streptococcus pyogenes, or group A streptococcus, is responsible for mild infections to life-threatening diseases. To determine the primary transcriptome of the emm1 strain S119, we have performed a differential RNA-Seq experiment based on selective Tobacco Acid Pyrophosphatase (TAP) treatment and 5' adapter ligation to differentiate primary transcripts (5' tri-phosphate) and processed RNAs (5' mono-phosphate). The libraries were performed on a mixture of RNAs prepared from bacteria cultured to late exponential phase in a rich growth culture medium supplemented or not with 15 mM of MgCl2
Project description:The human pathogen Streptococcus pyogenes, or group A streptococcus, is responsible for mild infections to life-threatening diseases. We previously have performed the transcription start site profiling of a Streptococcus pyogenes emm1 strain, strain S119, an invasive strain isolated from a blood culture. Here, we perform strand-specific RNA-seq experiments to complete this characterization and analyze the global coverage and the differential expression in growth medium complemented or not with 15 mM MgCl2. In addition we compare these results to those obtained with a related strain, strain S126, corresponding to a colonization sample, that differs from S119 by only one mutation in the two-component regulator of virulence CovRS.
Project description:Streptococcus pyogenes is a major causative agent of tonsillitis or pharyngitis in children, which can lead to more invasive infections and noninfectious sequellae. S. pyogenes can persist in tonsils, while one-third of children treated with antibiotics continue to shed streptococci and have recurrent infections. Mouse nasal-associated lymphoid tissue (NALT) is functionally analogous to human oropharangeal lymphoid tissues. The innate immune responses of naïve cells from a mucosal site to S. pyogenes is not well described; therefore, we infected C57BL/6 mice intranasally with 108 CFU S. pyogenes. Transcriptional responses by NALT after S. pyogenes infection were analyzed by Affymetrix microarray and quantitative RT-PCR. Wild-type S. pyogenes induces transcription of both type I and IFN-gamma-responsive genes, pro-inflammatory genes, and acute phase response plasma proteins within 24h after infection. Invasion of NALT and the induction of the interferon response were not dependent on expression of anti-phagocytic M1 protein. However, infection with an attenuated, less invasive mutant indicated that a robust innate response by NALT is significantly influenced by intra-NALT bacterial load. Granulocytic populations of NALT, cervical lymph nodes and spleen were discriminated by characteristic surface and intracellular markers. Intranasal infection induces systemic release of neutrophils and a substantial influx of neutrophils into NALT at 24h, which decline by 48h after infection. Macrophages do not significantly increase in S. pyogenes-infected NALT. Intranasal infection of IFN-gamma -/- (GKO) C57BL/6 mice did not lead to systemic dissemination of wild type S. pyogenes, despite reduced expression of IFN-gamma-responsive mRNAs in NALT. Infected GKO mice had an unregulated influx of neutrophils into NALT compared to immunocompetant mice and mice treated with an anti-IFN-gamma antibody more rapidly cleared S. pyogenes from NALT. Thus, IFN-gamma-induced responses have a suppressive influence on early clearance of this pathogen from NALT. Experiment Overall Design: C57BL/6 mice (6-10 weeks old), 4 per group, were infected intranasally with log-phase Streptococcus pyogenes, 2 to 4 x 10^8 CFU per 15 µl of pyrogen-free PBS. Sham-infected mice were administered 15 µl of the same PBS. Mice were infected with wild type strain 90-226 (Cue 1998), a 90-226 strain containing an in-frame deletion of M1 protein (90-226 delta emm1) (Zimmerlein 2005) or an attenuated 90-226 which lacks both M1 and SCPA proteins (90-226att). NALT was collected from mice at 24h after infection and stored in RNAlater until RNA could be purified).
Project description:Streptococcus agalactiae, also known as Group B streptococcus, emerged in the 1960s as a leading cause of septicemia and meningitis in neonates. It is also an increasing cause of infections in adults with underlying diseases. To characterize transcription start sites (TSS) in the hypervirulent ST17 lineage (strain BM110) we used a differential RNA-seq strategy, based on selective Tobacco Acid Pyrophosphatase (TAP) treatment and adapter ligation, which differentiates primary transcripts and processed RNAs
Project description:In Streptococcus pyogenes, mutation of GidA results in avirulence despite the same growth rate as the wild type. To understand the basis of this effect, global transcription profiling was conducted. Keywords: Wild type vs. GidA mutant Streptococcus pyogenes