Project description:Francisella tularensis may enter the body thorugh the lungs and cause fatal infection. In this study the inflammatory response to the virulent strain of Francisella (Schu4) was mapped over a 96h time-course using a custom microarray. Six groups of 4 mice were exposed to aerosolised Francisella tularensis and a three groups exposed to vehicle only control (media only). Following exposure mice were culled at 4 timepoints (1, 24, 48 and 96h). RNA was extracted and run on the custom array.
Project description:Virulent Francisella tularensis induces a unique pulmonary inflammatory response characterized by temporal regulation of innate immune pathways correlating with altered bacterial gene expression patterns. The pulmonary transcriptional response to aerosolized virulent F. tularensis was compared to other lethal and non-lethal respiratory pathogens.
Project description:Francisella tularensis may enter the body thorugh the lungs and cause fatal infection. In this study the inflammatory response to the virulent strain of Francisella (Schu4) was mapped over a 96h time-course using a custom microarray.
Project description:Francisella tularensis is a Gram-negative bacterium that causes a fatal human disease known as tularemia. The Centers for Disease Control have classified F. tularensis as Category A Tier-1 Select Agent. The virulence mechanisms of Francisella are not entirely understood. Francisella possesses very few transcription regulators, and most of these regulate the expression of genes involved in intracellular survival and virulence. The F. tularensis genome sequence analysis reveals an AraC (FTL_0689) transcriptional regulator homologous to the AraC/XylS family of transcriptional regulators. In Gram-negative bacteria, AraC activates genes required for L-arabinose utilization and catabolism. The role of the FTL_0689 regulator in F. tularensis is not known. In this study, we characterized the role of FTL_0689 in gene regulation of F. tularensis and investigated its contribution to intracellular survival and virulence. The results demonstrate that FTL_0689 in Francisella is not required for L-arabinose utilization. Instead, FTL_0689 specifically regulates the expression of the oxidative and global stress response, virulence, metabolism, and other key pathways genes required by Francisella when exposed to oxidative stress. The FTL_0689 mutant is attenuated for intramacrophage growth, and mice infected with the FTL_0689 mutant survive better than wild-type F. tularensis LVS infected mice. Based on the deletion mutant phenotype, FTL_0689 was termed osrR (oxidative stress response regulator). Altogether, this study elucidates the role of the osrR transcriptional regulator in tularemia pathogenesis.
Project description:Eight week old female C57 Black mice were fasted for 24 hours prior to a single intraperitoneal injection of 350mg/kg of acetaminophen in phosphate buffer saline (PBS) (treatment group) or PBS (control group). The mice were euthanized at different time points post exposure (4, 24, or 48 hours after exposure to Francisella tularensis subspecies tularensis SchuS4).
Project description:Francisella tularensis subsp. tularensis Induces a Unique Pulmonary Inflammatory Response: Role of Bacterial Gene Expression in Temporal Regulation of Host Defense Responses
Project description:Differential expression in human peripheral blood monocytes between F. novicida-infected and uninfected, and between Francisella tularensis tularensis isolate Schu S4 and uninfected. The goal was to examine genomewide transcriptional reponses to these two strains, and identify differentially-regulated genes that may help explain the virulence of Schu S4. Keywords: Immune Response, Human Monocytes, Bacteria, Francisella
