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 regulatory elements in this species we performed a genome-wide transcription start site (TSS) profiling and whole-transcript sequencing. TSS were identified by using a differential RNA-seq strategy, based on selective Tobacco Acid Pyrophosphatase (TAP) treatment and adapter ligation, which differentiates primary transcripts and processed RNAs. The accuracy and sensitivity of TSS identification were increased by combining differential RNA-seq analyses under eight conditions corresponding to variations in growth conditions and genetic backgrounds. Whole-transcript sequencing used a two-step adaptor ligation-based directional RNA-seq protocol and was performed under two experimental conditions with triplicate experiments to assess variations in gene expression in response to an acid stress

2015-04-21 | E-MTAB-3200 | biostudies-arrayexpress

Mutation Mapping of 40 Streptococcus suis strains

Project description:Streptococcus suis is an important zoonotic pathogen that can cause meningitis and sepsis in both pigs and humans. In this study,we evaluated the genetic difference of 40 Streptococcus suis strains belonging to various sequence types by comparative genomic hybridization to identify genes associated with the variation in pathogenicity using NimbleGen’s tilling microarray platform. Application of Comparative Phylogenomics to Identify Genetic Differences Relating to Pathogenicity of Streptococcus suis

2014-05-20 | GSE40035 | GEO

CiaR Transcriptome in Streptococcus agalactiae

Project description:Regulation of gene expression in response to variable and often adverse environmental conditions is an essential component of microbial pathogenesis. We identified the two-component regulatory system CiaRH in a screen for genes essential for the survival of Streptococcus agalactiae (Group B Streptococcus, GBS) on exposure to in vitro models of environmental stress. We constructed site-directed, non-polar deletion mutations in the regulator gene ciaR and compared the growth of CiaR mutant GBS to wild-type GBS under stressed conditions. CiaR mutant GBS are more sensitive than wild-type GBS to elevated temperature, low pH, chemical mutagens and ultraviolet light; the mutants are also more sensitive to cell-wall active antibiotics and antimicrobial peptides. CiaR mutant strains are markedly attenuated in a mouse model of GBS sepsis. To determine the genes regulated by CiaR that account for these defects, transcriptional profiling was performed using DNA microarray analysis, comparing wild-type GBS to CiaR mutant GBS under non-stressed conditions.

2012-11-18 | GSE14569 | GEO

LiaR Transcriptome in Streptococcus agalactiae

Project description:Streptococcus agalactiae (Group B Streptococcus, GBS) is a leading cause of early-onset neonatal bacterial infection. Evasion of innate immune defenses is critical to neonatal GBS disease pathogenesis. Effectors of the innate immune system such as antimicrobial peptides, as well as numerous antibiotics, target the peptidoglycan layer of the gram positive bacterial cell wall. The intramembrane-sensing histidine kinase class of two-component regulatory systems has recently been identified as important to the gram-positive response to cell wall stress. We identified and characterized the GBS homolog of LiaR, the response regulator component of the LiaFSR system and constructed site-directed, non-polar deletion mutations in the regulator gene liaR. GBS LiaR deletion mutant strains are more susceptible to cell wall active antibiotics (vancomycin and bacitracin) as well as antimicrobial peptides (colistin, nisin and the human cathelicidin LL-37) compared to isogenic wild-type GBS. LiaR mutant GBS are significantly attenuated in mouse models of both GBS sepsis and GBS pneumonia. To determine the genes regulated by LiaR that account for these defects, transcriptional profiling was performed using DNA microarray analysis, comparing wild-type GBS to LiaR mutant GBS under non-stressed conditions.

2012-11-18 | GSE14571 | GEO

Epigenome Wide Association Study unveils differential methylation of Leukocyte cell adhesion molecules in neonatal sepsis

Project description:DNA methylation is the current strategy in the field of biomarker discovery due to its prognostic efficiency. Its role in prognosis and early diagnosis has been recognized in various types of cancer. Sepsis still remains one of the major causes of neonatal mortality due to the lack of sensitive diagnostic and prognostic biomarkers. Delay in sepsis diagnosis leads to treatment difficulties and poor outcomes. In this study, we have done an epigenome wide search to identify potential markers for prognosis of neonatal sepsis which may improve the treatment strategies. Illumina 450K methylation microarray revealed that the genes involved in transendothelial leukocyte migration were differentially methylated in septic newborns compared to non-septic newborns, especially the Protocadherin Beta group. Genes like ITGB2-AS1, CCS were found to be differentially methylated significantly, which gives the hope of developing novel, potential epigenetic markers for neonatal sepsis. From this study, we conclude that DNA methylation might play crucial functions in the pathophysiology of neonatal sepsis which was obvious from the difference in methylation level among septic and non-septic babies. In future, the potentiality of these epigenetic biomarkers can be studied in large scale with appropriate techniques which will give further in depth knowledge in this context. DNA methylation analysis of three septic newborns and three non-septic newborns were performed with Illumina Infinium HumanMethylation450 BeadChip. Peripheral venous blood sample was collected from the babies during the third day of birth while taking blood for routine investigations. Non-septic babies are babies admitted to NICU and sampled for other minor ailments. Genomic DNA was extracted using QIAmp DNA Blood Mini kit (Qiagen, Hilden, Germany) and bisulfite treated using EZ DNA methylation kit (Zymoresearch, USA).

2014-06-20 | E-GEOD-58651 | biostudies-arrayexpress

Mutation Mapping of 40 Streptococcus suis strains

Project description:Streptococcus suis is an important zoonotic pathogen that can cause meningitis and sepsis in both pigs and humans. In this study,we evaluated the genetic difference of 40 Streptococcus suis strains belonging to various sequence types by comparative genomic hybridization to identify genes associated with the variation in pathogenicity using NimbleGenM-bM-^@M-^Ys tilling microarray platform. Application of Comparative Phylogenomics to Identify Genetic Differences Relating to Pathogenicity of Streptococcus suis Comparative genomic analysis on the 40 S.suis strains of different serotypes and ST types through tilling arrays

2014-05-20 | E-GEOD-40035 | biostudies-arrayexpress

Streptococcus pneumoniae TIGR4

Project description:Causes pneumonia, meningitis, and otitis media

| PRJNA277 | ENA

Streptococcus pneumoniae TIGR4

Project description:Causes pneumonia, meningitis, and otitis media

| PRJNA13923 | ENA