ABSTRACT: Comparison of the expression profiles of the Clostridium difficile 630E strain after 8h, 14h and 38h of infection in mouse and after 8h, 14h and 38h growth in vitro
Project description:The virulence factors of Clostridium difficile have been studied for many years, but the main in vivo pathogenesis processes of this bacterium has to be investigated. Especially, data on the early mechanisms of C. difficile adaptation to the host is not yet available. The objective of our study was to improve the understanding of the pathogenesis of C. difficile by the analysis of the genome-wide temporal expression of C. difficile genes during the first hours of infection. Three groups of 4 axenic mice each were challenged by vegetative cells of the 630 C. difficile strain, and sacrified at 8, 14, and 38 hours post-infection. Pure prokaryotic RNA was obtained from caecal bacteria. Comparative hybridizations on strain 630 microarrays were done using cDNA issued from an 8-hours in vitro culture as control, with a dye-swap protocol for each sample. Normalisation and statistical analysis of all data were done with different functions of the limma package. The pathogenesis of C. difficile could be seen as a result of the successful metabolic adaptation of the bacteria to its host, contributing to its persistence and multiplication, and the coordinate expression of virulence factors. Analysis of our data enlightened some of these aspects. The results support strongly a two-step infection model, since there is, during the course of infection, a significant increase in the toxins expression contrasting with a decreased expression of most of the putative colonization factors. Several paralogs of the HMW S-layer protein are also down-regulated, some of them could be strong candidates as colonisation factors. Bacterial adaptation to the microenvironment of the host is assessed by the regulation of numerous metabolic pathways, i.e., the upregulation of the ethanolamine catabolic operon or the modulation of several PTS systems. Inactivation of some putative virulence factors identified by this methodology will complete this analysis. Transcriptional profiling of the C. difficile 630E strain after 8h, 14h or 38h of infection in mouse. Three-condition experiments: 630E strain 8h, 14h or 38h of infection in mouse vs. 630E strain 8h in culture. 4 biological replicates for each condition in dye swap.
Project description:The virulence factors of Clostridium difficile have been studied for many years, but the main in vivo pathogenesis processes of this bacterium has to be investigated. Especially, data on the early mechanisms of C. difficile adaptation to the host is not yet available. The objective of our study was to improve the understanding of the pathogenesis of C. difficile by the analysis of the genome-wide temporal expression of C. difficile genes during the first hours of infection. Three groups of 4 axenic mice each were challenged by vegetative cells of the 630 C. difficile strain, and sacrified at 8, 14, and 38 hours post-infection. Pure prokaryotic RNA was obtained from caecal bacteria. Comparative hybridizations on strain 630 microarrays were done using cDNA issued from an 8-hours in vitro culture as control, with a dye-swap protocol for each sample. Normalisation and statistical analysis of all data were done with different functions of the limma package. The pathogenesis of C. difficile could be seen as a result of the successful metabolic adaptation of the bacteria to its host, contributing to its persistence and multiplication, and the coordinate expression of virulence factors. Analysis of our data enlightened some of these aspects. The results support strongly a two-step infection model, since there is, during the course of infection, a significant increase in the toxins expression contrasting with a decreased expression of most of the putative colonization factors. Several paralogs of the HMW S-layer protein are also down-regulated, some of them could be strong candidates as colonisation factors. Bacterial adaptation to the microenvironment of the host is assessed by the regulation of numerous metabolic pathways, i.e., the upregulation of the ethanolamine catabolic operon or the modulation of several PTS systems. Inactivation of some putative virulence factors identified by this methodology will complete this analysis. Transcriptional profiling of the C. difficile 630E strain after 8h, 14h or 38h in TY. Two-condition experiments: 630E strain 14h or 38h in TY vs. 630E strain 8h in TY. 2 biological replicates for each condition in dye swap.
Project description:This SuperSeries is composed of the following subset Series: GSE35070: Comparison of the expression profiles of 630E JIR8094 strain and a ccpA mutant after 10h of growth in TY with 0.5% glucose. GSE35071: Comparison of the expression profiles of 630E JIR8094 strain and a ccpA mutant after 10h of growth in TY. GSE35072: Clostridium difficile CD630E JIR8094: growth 10h with 0.5% glucose in TY vs growth 10h in TY GSE35073: Clostridium difficile mutant ccpA CD630E JIR8094: growth 10h with 0.5% glucose in TY vs growth 10h in TY Refer to individual Series
Project description:This SuperSeries is composed of the following subset Series: GSE25474: Comparison of the expression profiles of 630E strain after 4h and 10h of growth GSE25475: Comparison of the expression profiles of 630E strain and a sigH mutant after 10h of growth This study is based on two microarray datasets, in one hand a phase transition comparison using the expression profiles of 630E strain after 4h and 10h of growth. In other hand a comparison at 10h of growth between a mutant of the sigH gene and the WT strains. This experimental procedure was designed to investigate the effect of sigH in the growth phase transition of Clostridium difficile. Refer to individual Series
Project description:This study is based on two microarray datasets, in one hand a phase transition comparison using the expression profiles of 630E strain after 4h and 10h of growth. In other hand a comparison at 10h of growth between a mutant of the sigH gene and the WT strains. This experimental procedure was designed to investigate the effect of sigH in the growth phase transition of Clostridium difficile. This SuperSeries is composed of the SubSeries listed below.
Project description:Compartment-specific control of gene expression during Bacillus subtilis sporulation is governed by a cascade of four sigma factors, sigmaF and sigmaG in the forespore and sigmaE and sigmaK in the mother cell. In this work, we combined transcriptional analyses and transcriptional start site mapping to define the sigmaF, sigmaE, sigmaG and sigmaK regulons in Clostridium difficile. A total of about 225 genes were under the control of these sigma factors: 25 in the sigmaF regulon, 97 sigmaE-dependent genes, 50 sigmaG-governed genes and 56 genes specifically controlled by sigmaK. A significant fraction of genes in each regulon are of unknown function and we can propose new candidates for spore coat proteins synthesized under the control of sigmaE and sigmaK among proteins previously detected in the spore proteome (Lawley et al., 2009 (PMID 19542279)). Global analysis of developmental gene expression under the control of these sigma factors indicate deviations from the B. subtilis model regarding the communication between mother cell and forespore in C. difficile. We show that the expression of the sigmaE regulon in the mother cell is not strictly under the control of sigmaF despite the fact that the forespore product SpoIIR is required for the processing of pro-sigmaE. In addition, the sigmaK regulon is not controlled by sigmaG in C. difficile in connection with the lack of pro-sigmaK processing in this bacterium. However, a control of the forespore on sigmaK targets is maintained through a sigmaF-dependent regulation of sigmaK-controlled genes, a process that bypasses sigmaG. Here, transcriptional profiling of the Clostridium difficile 630E strain vs. a sigE mutant after 14h of growth in MS is performed. Two-condition experiment: 630E strain 14h vs. sigE mutant 14h. 4 biological replicates for each condition, including dye-swaps.
Project description:Compartment-specific control of gene expression during Bacillus subtilis sporulation is governed by a cascade of four sigma factors, sigmaF and sigmaG in the forespore and sigmaE and sigmaK in the mother cell. In this work, we combined transcriptional analyses and transcriptional start site mapping to define the sigmaF, sigmaE, sigmaG and sigmaK regulons in Clostridium difficile. A total of about 225 genes were under the control of these sigma factors: 25 in the sigmaF regulon, 97 sigmaE-dependent genes, 50 sigmaG-governed genes and 56 genes specifically controlled by sigmaK. A significant fraction of genes in each regulon are of unknown function and we can propose new candidates for spore coat proteins synthesized under the control of sigmaE and sigmaK among proteins previously detected in the spore proteome (Lawley et al., 2009 (PMID 19542279)). Global analysis of developmental gene expression under the control of these sigma factors indicate deviations from the B. subtilis model regarding the communication between mother cell and forespore in C. difficile. We show that the expression of the sigmaE regulon in the mother cell is not strictly under the control of sigmaF despite the fact that the forespore product SpoIIR is required for the processing of pro-sigmaE. In addition, the sigmaK regulon is not controlled by sigmaG in C. difficile in connection with the lack of pro-sigmaK processing in this bacterium. However, a control of the forespore on sigmaK targets is maintained through a sigmaF-dependent regulation of sigmaK-controlled genes, a process that bypasses sigmaG. Here, transcriptional profiling of the Clostridium difficile 630E strain vs. a sigE mutant after 14h of growth in MS is performed. Two-condition experiment: 630E strain 14h vs. sigF mutant 14h. 4 biological replicates for each condition, including dye-swaps.