In vivo vs. In vitro
Conditions
| Title | Description | Overall Design | Pubmed ID | Samples | Series ID | Summary | Type |
|---|---|---|---|---|---|---|---|
| In vivo vs. In vitro |
Comparison of the expression profiles of the 630E strain after 8h, 14h and 38h of infection in mouse |
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. | 23897605 | GSM1060320 , GSM1060321 , GSM1060322 , GSM1060323 , GSM1060324 , GSM1060325 , GSM1060326 , GSM1060327 , GSM1060328 , GSM1060329 , GSM1060330 , GSM1060331 , GSM1060332 , GSM1060333 , GSM1060334 , GSM1060335 , GSM1060336 , GSM1060337 , GSM1060338 , GSM1060339 , GSM1060340 , GSM1060341 , GSM1060342 , GSM1060343 , GSM1060344 , GSM1060345 , GSM1060346 , GSM1060347 , GSM1060348 , GSM1060349 , GSM1060350 , GSM1060351 | GSE43303,GSE43305 | 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. | Expression profiling by array |