Project description:Wild-type (JRS4) and irr mutant (JRS550) Group A Streptococcus (GAS) strains growing in either early or late exponential phase Keywords = Human Keywords = Neutrophils Keywords = Bacterial Keywords = Gene Regulation Keywords = Inflammation Keywords: other
Project description:This transcriptional analysis is a follow up to a population genomic investigation of 3615 Streptococcus pyogenes serotype M1 strains whch are responsible for an epidemic of human invasive infections (www.pnas.org/cgi/doi/10.1073/pnas.1403138111), The goal was to assess gene expression differences between predecessor pre-epidemic M1 strains and their descendent epidemic M1 strains to gain insights into the underlying genetic basis for the shift in the frequency and severity of human infections caused by these pathogenic bacteria The transcriptomes of 7 GAS M1 strains, 4 pre-epidemic and 3 epidemic, were compared at two phases of growth, mid-exponential and early-stationary, using 3 biologial replicates, to identify genes differentially expressed between the pre-epidemic and epidemic isolates with the goal of to gaining insight into the underlying genetic basis for the evolutionary emergence, increased frequency and severity of the epidemic strains relative to the pre-epidemic strains
Project description:Transcriptional profiling of Streptococcus pyogenes MGAS5005 cells comparing control untreated GAS cells with GAS cells exposed to 4uM heme for 1.5 h
Project description:The nasopharynx and the skin are the major oxygen-rich anatomical sites for colonization by the human pathogen Streptococcus pyogenes (group A Streptococcus, GAS). To establish infection, GAS must survive oxidative stress generated during aerobic metabolism and the release of reactive oxygen species (ROS) by host innate immune cells. Glutathione is the major host antioxidant molecule while GAS is glutathione-auxotrophic. Here we report the molecular characterization of the ABC transporter substrate binding protein GshT in the GAS glutathione salvage pathway. We demonstrate that glutathione uptake is critical for aerobic growth of GAS and that impaired import of glutathione induces oxidative stress that triggers enhanced production of the reducing equivalent NADPH. Our results highlight the interrelationship between glutathione assimilation, carbohydrate metabolism, virulence factor production and innate immune evasion. Together, these findings suggest an adaptive strategy employed by extracellular bacterial pathogens to exploit host glutathione stores for their own benefit.
Project description:Streptococcus pyogenes (Group A streptococcus, GAS) is an important human pathogen that causes a variety of infectious diseases and sequelae. Recent studies showed virulence factor expression was controlled at multiple levels, including the post-transcriptional regulation. In this study, we examined the global half-lives of S. pyogenes mRNAs and explored the role RNase Y played in mRNA metabolism with microarray analysis. key word: genetic modification
