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
Project description:Francisella tularensis, the etiological agnet of Tularemia is a Category A select agent. Preparedness means for prompt proper antibiotic treatment are of need to prevent morbidity and mortality. While standard antimicrobial susceptibility tests are time consuming, the quantification of the changes in the expression levlels of specific mRNA markers folowing antibiotic exposure may enable a rapid determination of antimicrobial susceptibility. We submit transcriptomic data sets detailing global gene expression of F. tularensis following exposure to Doxycycline or Ciprofloxacin antibiotics.
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:Francisella tularensis, is an extremely virulent bacterium that can be transmitted naturally by blood sucking arthropods. During mammalian infection, F. tularensis infects numerous types of host cells, including erythrocytes. As erythrocytes do not undergo phagocytosis or endocytosis, it remains unknown how F. tularensis invades these cells. Furthermore, the consequence of inhabiting the intracellular space of red blood cells has not been determined. Here, we provide evidence indicating that residing within an erythrocyte enhances the ability of F. tularensis to colonize ticks following a blood meal.
Project description:These samples are part of an experiment comparing the expression profiles of Francisella tularensis novicida grown in chemically defined medium and bacteria isolated 24 hours post infection of J774 macrophages to identify virulence factors
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:To understand differences of gene expression profiles between Francisella strains RNA profiles of Francisella strains were generated by deep sequencing, in triplicate, using NovaSeq6000. qRT–PCR validation was performed using SYBR Green assays. Our study represents the first detailed differential transcriptomic analysis of Francisella strains , with biologic replicates, generated by RNA-seq technology.
Project description:Francisella tularensis is classified as a Category A priority pathogen and causes fatal disseminated disease in humans upon inhalation of less than 50 bacteria. Although drugs are available for treatment, they are not ideal because of toxicity and delivery, and in some cases relapse upon withdrawal. We have an ongoing program in the development of novel FabI enoyl-ACP-reductase enzyme inhibitors for Francisella and other select agents. To establish ftFabI in F. tularensis as a clinically relevant drug target, we demonstrated that the enzyme is essential for growth in vitro and that ftfabI is not transcriptionally altered in the presence of exogenous fatty acids. Inhibition of ftFabI results in loss of viability that is not rescued by exogenous fatty acids supplementation. Importantly, whole-genome transcriptional profiling of F. tularensis with DNA microarrays from infected tissues revealed that ftfabI and de novo fatty acid biosynthetic genes are transcriptionally active during infection. This is the first demonstration that the FabI enoyl-ACP-reductase enzyme encoded by F. tularensis is essential and that de novo fatty acid biosynthetic components are transcriptionally active during infection in the mouse model tularemia.
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. Experiment Overall Design: Human monocytes were infected with the Schu S4 isolate of Francisella tularensis tularensis (n=4), with F. tularensis subspecies novicida isolate U112 (n=4) or were left uninfected (n=6). Gene expression values were calculated using the gcrma package in R and BioConductor, and limma to identify differentially expressed genes. Submitted here are expression values calculated using R 2.7.1 and BioConductor 2.2 (FreeBSD/amd64) but the original were done using R 2.6.1 and BioConductor 2.1 (FreeBSD/amd64). Twelve other chips were pooled with these 14 for preprocessing.
