Project description:The poly(A)+ and poly(A)− fractions of interacting and non-interacting cells were used for distinct library preparation of interacting and non-interacting prokaryotic pathogen and eukaryotic host cells by deepSuperSAGE. Sequencing was performed with the Illumina HiSeq 2000 platform, and one point of time post infection (early interaction) was additionally prepared by Massive Analysis of cDNA Ends (MACE) as alternative tag-based library preparation method.
Project description:The poly(A)+ and poly(A)− fractions of interacting and non-interacting cells were used for distinct library preparation of interacting and non-interacting prokaryotic pathogen and eukaryotic host cells by deepSuperSAGE. Sequencing was performed with the Illumina HiSeq 2000 platform, and one point of time post infection (early interaction) was additionally prepared by Massive Analysis of cDNA Ends (MACE) as alternative tag-based library preparation method. 10 deepSuperSAGE and 2 MACE libraries. Please consult the publication mentioned in the following for more details.
Project description:Characterization of the zebrafish embryonic host response to systemic bacterial infection with Salmonella typhimurium wild type strain (SL1027) and its isogenic LPS O-antigen mutant Ra (SF1592) by means of a time-resolved global expression analysis.
Project description:The microbiota generates structurally diverse small molecules that can regulate host physiology and disease. Of these microbiota metabolites, bile acids have emerged as important modulators of host immunity and microbial pathogenesis. While the modes of action for different bile acids on host pathways are becoming more apparent, the mechanisms by which these prominent microbiota metabolites suppress microbial virulence pathways are less clear. To identify the direct protein targets of bile acids in Salmonella, we have generated three photoaffinity bile acid reporters (alk-X-CDCA, alk-X-UDCA, alk-X-LCA) and performed chemical proteomics. Using a combination of photocrosslinking with bile acid chemical reporters and label-free proteomics, we performed a quantitative analysis of bile acid interacting proteins in Salmonella with or without UV-mediated photocrosslinking. These studies revealed bile acid can interact with many Salmonella proteins, such as extracellular or secreted proteins, T3SS components and motility-related proteins, as predicted by Gene Ontology analysis. In addition, cytoplasmic and membrane proteins including metabolic enzymes are also identified. Notably, HilD, an important transcriptional regulator of S. Typhimurium virulence was also identified by the alk-X-CDCA reporter. This study highlights the utility of chemical proteomics to identify the direct protein targets and mechanisms of action for microbiota metabolites in bacterial pathogens.
Project description:We investigated the interaction of Salmonella Typhimurium with Embryonic stem cell derived Dendritic Cells (ESDCs) as a new model to study host-pathogen interaction.
Project description:Infection with Salmonella enterica serovar Typhi in humans causes the systemic, life-threatening disease typhoid fever. In the laboratory, typhoid fever can be modeled through the inoculation of susceptible mice with Salmonella enterica serovar Typhimurium. The ensuing disease is characterized by systemic dissemination and colonization of many organs, including the liver, spleen and gallbladder. Using this murine model, we previously characterized the interactions between Salmonella Typhimurium and host cells in the gallbladder and showed that this pathogen can successfully invade gallbladder epithelial cells and proliferate. Additionally, we showed that Salmonella Typhimurium can use bile phospholipids to grow at high rates. These abilities are likely important for quick colonization of the gallbladder during typhoid fever and further pathogen dissemination through fecal shedding. To further characterize the interactions between Salmonella and the gallbladder environment we compared the transcriptome of Salmonella cultures grown in LB or physiological murine bile. Our data showed that many genes involved in bacterial central metabolism are affected by bile, with the citric acid cycle being repressed and alternative respiratory systems being activated. Additionally, our study revealed a new aspect of Salmonella interactions with bile through the identification of phoP as a bile-responsive gene. Repression of phoP expression does not involve PhoPQ sensing of a bile component. Due to its critical role in Salmonella virulence, further studies in this area will likely reveal aspects of the interaction between Salmonella and bile that are relevant to disease.
Project description:SrfJ is an effector of the type III secretion systems of the Gram-negative intracellular pathogen Salmonella enterica serovar Typhimurium. To study the effects of this effector on global gene expression in host cells, we have infected murine RAW264.7 macrophages with two strains of Salmonella enterica serovar Typhimurium. The comparison between cells infected with the wild-type strain and cells infected with a srfJ mutant revealed a number of genes that are differentially expressed when SrfJ is present.
Project description:During an infection, bacteria are exposed to the complex host immune response and has to adapt to the changing environment in order to successfully grow within tissues. In the present sturdy we analysed the transcriptome of both host (mouse) and bacteria (Salmonella Typhimurium) at different time points during the infection to gain a better insight into the attack mounted by the host to repel the bacterial infection and how the bacteria adapts to it. For this, mice were infected intravenously with Salmonella Typhimurium and spleens were collected for RNA isolation at specific time points. Transcription profile of infected mice was compared to uninfected controls.
Project description:Many non-typhoidal serovars of Salmonella such as Salmonella enterica serovar Typhimurium (S. Typhimurium) are the leading cause of food-borne gastroenteritis, resulting in millions of infections each year and sometimes death. Salmonella enterica serovar Typhimurium is the most common non-typhoidal Salmonella strain isolated from patients around the world and is used as a mouse model to study bacterial pathogenesis and host-microbe interactions. Furthermore, S. Typhimurium is an important pathogen in livestock animals including chickens and cattle. S. Typhimurium utilises a multitude of virulence factors to reach and invade host cells and for its intracellular survival. However, little is known about the mechanism of protein synthesis of these virulence factors at the codon level. Here, we performed RNA-seq and ribosome profiling. Ribosome profiling allows the global mapping of translating ribosomes on the transcriptome and therefore provides direct measure of protein synthesis.
Project description:The long external filament of bacterial flagella is composed of several thousand copies of a single protein, flagellin. Here, we explore the role played by lysine methylation of flagellin in Salmonella, which requires the methylase FliB. We show that both flagellins of Salmonella enterica serovar Typhimurium, FliC and FljB, are methylated at surface-exposed lysine residues by FliB. A Salmonella Typhimurium mutant deficient in flagellin methylation is outcompeted for gut colonization in a gastroenteritis mouse model, and methylation of flagellin promotes bacterial invasion of epithelial cells in vitro. Lysine methylation increases the surface hydrophobicity of flagellin and enhances flagella-dependent adhesion of Salmonella to phosphatidylcholine vesicles and epithelial cells.