E. coli intracellular metabolism across various growth conditions
Ontology highlight
ABSTRACT: FIA-TOF measurements of intracellular metabolites in E. coli cells grown across a range of 40 diverse conditions. See associated publication for details.
Project description:FIA-TOF measurements of intracellular metabolites in E. coli cells grown across a range of 40 diverse conditions. See associated publication for details.
Project description:Mycobacterium tuberculosis (Mtb) infection of macrophages reprograms cellular lipid metabolism to promote the formation of cytosolic lipid droplets. While it is clearly known that intracellular Mtb utilize host derived fatty acids and cholesterol to fuel a majority of its biosynthetic demands, the role of macrophage lipid metabolism on the bacteria’s ability to access the intracellular lipid pool remains controversial. We have utilized a CRISPR genetic knockdown approach to, systematically and comprehensively, characterize the role of macrophage fatty acid metabolism on the intracellular growth of Mtb. Our analyzes demonstrate that knockdown of lipid import, sequestration and metabolism genes collectively impair the intracellular growth of Mtb in macrophages. We further demonstrate that modulating fatty acids homeostasis in macrophages impair Mtb replication by enhancing production of pro-inflammatory cytokines, restricting the bacteria access to nutrients and increasing oxidative stress in a manner which is surprisingly divergent. We also demonstrate that impaired macrophage lipid droplet biogenesis is restrictive to intracellular Mtb growth. However, increased induction of lipid droplet formation by downstream blockade of fatty acid oxidation does not rescue the impaired Mtb growth phenotypes. Our work provides a characterization of macrophage fatty acid homeostasis and how its modulation impacts Mtb intracellular growth.
Project description:This project makes in depth measurements of protein and rna gene expression of E. coli under various environmental conditions including glycerol, lactate, gluconate, NaCl and MgSO4.
Project description:Salmonella invasion of non-phagocytic cells is a dynamic process that requires the translocation of effector proteins into host cells by a type III secretion system (T3SS1) encoded on Salmonella pathogenicity island 1 (SPI1). The signals involved in T3SS1 induction in vivo are not known, but SPI1-induced invasive Salmonella can be prepared by growth in synthetic media. Here we compared two different methods of preparing SPI1-induced bacteria by using a combination of transcriptome analysis, a single-cell reporter assay and intracellular gene expression analysis to reveal clear differences between these two bacterial populations that are reflected in their ability to interact with cultured epithelial cells. Invasion efficiency and intracellular replication were greater for bacteria grown with aeration to late-log phase compared to those grown without aeration to stationary phase. No significant differences in SPI1 regulon expression were revealed by transcriptome analysis. By contrast, surface appendage and stress response genes were considerably changed. Single cell analyses of gene expression revealed variation in the frequency of SPI1-induced bacteria and a correlation between SPI1-induction and the presence of flagella. The expression of virulence genes following invasion of cultured epithelial cells was also found to be predetermined by pre-invasion growth conditions. Key words: epithelial, flagella, invasion, motility, Salmonella-containing vacuole, treatment of shaking versus treatment of static growth conditions for St-SL1344
Project description:Salmonella invasion of non-phagocytic cells is a dynamic process that requires the translocation of effector proteins into host cells by a type III secretion system (T3SS1) encoded on Salmonella pathogenicity island 1 (SPI1). The signals involved in T3SS1 induction in vivo are not known, but SPI1-induced invasive Salmonella can be prepared by growth in synthetic media. Here we compared two different methods of preparing SPI1-induced bacteria by using a combination of transcriptome analysis, a single-cell reporter assay and intracellular gene expression analysis to reveal clear differences between these two bacterial populations that are reflected in their ability to interact with cultured epithelial cells. Invasion efficiency and intracellular replication were greater for bacteria grown with aeration to late-log phase compared to those grown without aeration to stationary phase. No significant differences in SPI1 regulon expression were revealed by transcriptome analysis. By contrast, surface appendage and stress response genes were considerably changed. Single cell analyses of gene expression revealed variation in the frequency of SPI1-induced bacteria and a correlation between SPI1-induction and the presence of flagella. The expression of virulence genes following invasion of cultured epithelial cells was also found to be predetermined by pre-invasion growth conditions. Key words: epithelial, flagella, invasion, motility, Salmonella-containing vacuole,
Project description:Acute infection of the central nervous system is one of the deadliest diseases, but the mechanisms by which intracellular bacteria infiltrate the brain remain poorly understood. Phagocytic cells are usually recognized as the battlefield on which war is waged against intracellular bacteria; however, little is known about how the intracellular bacteria take advantage of infected phagocytes to access the brain. In this study, we find that a novel CD36+ foamy macrophage subpopulation participates in penetration of the brain by intracellular bacteria. Biomechanical analysis reveals that abundant protrusions and adhesion molecules on foamy macrophages confer significant resistance to the mechanical stress of blood flow, thereby providing more opportunities for these macrophages to adhere to the vascular endothelial surface during neuroinvasion. Through metabolomics analysis, we find that macrophage lipid metabolism is recalibrated during bacterial neuroinvasion, and that β-hydroxybutyrate promotes the formation and survival of CD36+ foamy macrophages. Taken together, our findings uncover a pathway by which intracellular bacteria hijack macrophages to invade the brain, suggesting that lipid metabolism might play a role in the prevention or resolution of bacterial neuroinvasion.
Project description:The aim of the project is to identify transcriptome-wide binding sites for the global RNA-binding protein ProQ in Salmonella during intracellular-like conditions.
Project description:A genome reduced E. coli strain MDS42ΔgalK::Ptet-gfp-kan were applied for the comparative transcriptome analysis. Genome-wide transcriptional changes under high osmotic prresure, high temperature condition and starvation were evaluated.