Project description:FabR ChIP-chip on Salmonella enterica subsp. enterica serovar Typhimurium SL1344 using anti-Myc antibody against strain with chromosomally 9Myc-tagged FabR (IP samples) and wildtype strain (mock IP samples)
Project description:The Salmonella enterica serovar Typhimurium (ST) mutant lacking the msbB gene (ΔmsbB) has been widely studied as a candidate for attenuated bacterial vectors in therapeutic applications. Deletion of msbB results in LPS with under-acylated lipid A, which lowers endotoxicity while maintaining structural integrity. This attenuation has traditionally been attributed to reduced TLR4 activation due to weaker interaction between the modified lipid A and TLR4. In our study, we confirmed that ΔmsbB ST was less lethal than wild-type (WT) ST in a mouse sepsis model. However, this difference persisted even in TLR4- and caspase-11-deficient mice, suggesting that LPS signaling is not the primary determinant of virulence. In vitro, bone marrow–derived macrophages (BMDMs) from TLR4- or caspase-11-deficient mice showed only modest reductions in ST-induced cell death and cytokine production. Importantly, ΔmsbB ST behaved similarly to WT ST in these assays, further indicating that LPS-mediated signaling is not central to the observed attenuation. Additionally, the mutant exhibited increased outer membrane permeability, likely contributing to its heightened antibiotic sensitivity—and reduced motility due to lower flagellin protein levels.
Project description:Obacunone is a limonoids present in Citrus species. We previously reported that obacunone was inhibitory to the cell-cell signaling in Vibrio harveyi and Escherichia coli O157:H7. In the present work we evaluated the effect of obacunone on the food borne pathogen Salmonella Typhimurium LT2 using cDNA microarray. The results demonstrate that obacunone exerts an antivirulence effect on S. Typhimurium LT2 by repressing SPI1 and SPI2. Furthermore, the effect of obacunone seems to be dependent upon EnvZ.
Project description:To investigate the effects of MccY on Salmonella Typhimurium, Ton system genes mutants were constructed and RNA-seq analysis were performed.