Fig 7.

Expression of the prdA and grdE genes of wild-type and mutant strains in the presence of l-proline or glycine. C. difficile wild-type (JIR8094), LB-CD4 (prdB::ermB), and LB-CD12 (grdA::ermB) strains were grown to mid-exponential phase in TY medium alone or supplemented with 30 mM l-proline or 30 mM glycine. RNA was harvested, cDNA was synthesized, and qPCR was performed using gene-specific primers for prdA (A) and grdE (B). Results were normalized to an internal control gene (rpoC) and are presented as the ratio of each transcript level to that of wild-type cells grown in BHIS. The means and standard deviations of at least three biological replicates, each assayed in triplicate, are shown.