Project description:Streptococcus pneumoniae normally resides in the human nasopharynx in a non-disease state. In response to yet unknown triggers it can descend to the lower respiratory tract and/or invade the bloodstream. Regulation and activation of virulence genes play essential roles in this process of disease development. A putative transcriptional regulator in S. pneumoniae, MgrA, with homology to a virulence gene activator, mga, of Group A streptococcus (GAS) was previously identified as being required for development of pneumonia in a murine model. In this work we confirm that mgrA is required for both nasopharyngeal carriage and pneumonia. Transcriptional profiling by microarray technology through the growth course of a strain that bears a deletion of mgrA (AC1500) with that of a strain that over expresses Mgra (AC1481) is used to show that MgrA acts as a repressor of the previously characterized rlrA pathogenicity islet. This is manifested phenotypically by a decrease in adherence to epithelial cells in tissue culture since rlrA pathogenicity islet contains genes mediating adherence.
Project description:Streptococcus pneumoniae normally resides in the human nasopharynx in a non-disease state. In response to yet unknown triggers it can descend to the lower respiratory tract and/or invade the bloodstream. Regulation and activation of virulence genes play essential roles in this process of disease development. A putative transcriptional regulator in S. pneumoniae, MgrA, with homology to a virulence gene activator, mga, of Group A streptococcus (GAS) was previously identified as being required for development of pneumonia in a murine model. In this work we confirm that mgrA is required for both nasopharyngeal carriage and pneumonia. Transcriptional profiling by microarray technology through the growth course of a strain that bears a deletion of mgrA (AC1500) with that of a strain that over expresses Mgra (AC1481) is used to show that MgrA . This is manifested phenotypically by a decrease in adherence to epithelial cells in tissue culture since rlrA pathogenicity islet contains genes mediating adherence. Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc. Computed
Project description:Streptococcus pneumoniae normally resides in the human nasopharynx in a non-disease state. In response to yet unknown triggers it can descend to the lower respiratory tract and/or invade the bloodstream. Regulation and activation of virulence genes play essential roles in this process of disease development. A putative transcriptional regulator in S. pneumoniae, MgrA, with homology to a virulence gene activator, mga, of Group A streptococcus (GAS) was previously identified as being required for development of pneumonia in a murine model. In this work we confirm that mgrA is required for both nasopharyngeal carriage and pneumonia. Transcriptional profiling by microarray technology through the growth course of a strain that bears a deletion of mgrA (AC1500) with that of a strain that over expresses Mgra (AC1481) is used to show that MgrA . This is manifested phenotypically by a decrease in adherence to epithelial cells in tissue culture since rlrA pathogenicity islet contains genes mediating adherence. Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc. Keywords: Logical Set
Project description:Streptococcus pneumoniae is a frequent coloniser of the human nasopharynx and a major cause of life-threating invasive infections such as pneumonia, meningitis and sepsis. Over 1 million people die every year due to invasive pneumococcal disease (IPD), mainly in developing countries. Serotype 1 is a common cause of IPD; however, unlike other serotypes, it is rarely found in the carrier state in the nasopharynx, which is often considered a prerequisite for disease. The aim of this study was to understand this dichotomy. We used murine models of carriage and IPD to characterise the pathogenesis of African serotype 1 (Sequence Type 217) pneumococcal strains obtained from the Queen Elizabeth Central Hospital in Blantyre, Malawi. We found that ST217 pneumococcal strains were highly virulent in a mouse model of invasive pneumonia, but in contrast to the generally accepted assumption, can also successfully establish nasopharyngeal carriage. Interestingly, we found that co-colonising serotypes may proliferate in the presence of serotype 1, suggesting that acquisition of serotype 1 carriage could increase the risk of developing IPD by other serotypes. RNAseq analysis confirmed that key virulence genes associated with inflammation and tissue invasiveness were upregulated in serotype 1. These data reveal important new insights into serotype 1 pathogenesis, with implications for carriage potential and risk of invasive disease through interactions with other co-colonising serotypes; an often overlooked factor in transmission and disease progression.
Project description:Shotgun metagenomic sequencing data for nasopharyngeal colonization dynamics with Streptococcus pneumoniae and associated antimicrobial-resistance in a South African birth cohort.
Project description:This SuperSeries is composed of the following subset Series: GSE33033: ahrC mutant compared to D39 wild-type in Streptococcus pneumoniae in CDM + 10 mM arginine GSE33034: argR1 mutant compared to D39 wild-type in Streptococcus pneumoniae in CDM + 10 mM arginine GSE33035: argR1-ahrC mutant compared to D39 wild-type in Streptococcus pneumoniae in CDM + 10 mM arginine GSE33036: Streptococcus pneumoniae D39 wild-type grown in CDM+10 mM arginine compared to D39 wild type grown in CDM + 0.05 mM arginine Refer to individual Series
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
Project description:Comparing transcriptome by means of DNA microarrays of Streptococcus pneumoniae D39 versus D39SM in medium without uracil. Details of this experiment are described in a paper with the title 'Interplay between capsule expression and uracil metabolism in Streptococcus pneumoniae'