GSE99224
Large-scale differences in gene expression, including genes encoding type IV pili-associated proteins, are seen when Clostridium perfringens is grown in liquid or on surfaces
Clostridium perfringens is a Gram-positive anaerobic pathogen that causes multiple diseases in humans and animals.  C. perfringens lack flagella but have type IV pili (TFP) and can glide on agar surfaces by forming filaments of cells aligned end to end.  When cells are placed on agar surfaces, they become elongated, flexible and have TFP on their surface.  To understand the basis of these phenotypes, cells were grown in three types of liquid media and on agar plates with the same medium to compare gene expression using RNA-seq.   Hundreds of genes were differentially expressed, including genes associated with TFP functions, which were higher on plates than in liquid.  The gusA gene, encoding the enzyme ß-glucuronidase, was inserted into the chromosome downstream of TFP promoters and expression measured in liquid and on plates.  ß-glucuronidase activity was proportional to the amount of transcripts seen with RNA-seq n liquid-grown cells, but not plate-grown cells, suggesting post-transcriptional regulation of these genes on surfaces.  An sRNA adjacent to pilA1 (SR79) was expressed at higher levels on plates in all media; overexpression of this sRNA resulted in longer cells on plates and shorter lag times in liquid suggesting SR79 plays a role in adapting to surface growth. Overall design: Comparison of gene expression in bacteria grown in liquid or on plates