Transcriptomal changes of Escherichia coli TolC grown with the biofilm inhibitor Carolacton

Carolacton is a novel biofilm inhibitor that kills biofilm cells of Streptococcus mutans and inhibits growth of the clinically relevant and human pathogenic bacterium Streptococcus pneumoniae TIGR4 in nanomolar concentrations. Interestingly, Carolacton also inhibits Escherichia coli with a defective outer membrane protein TolC . The cellular target of Carolacton is still unknown. Here, we adressed the differential transcription of cellular RNAs when E.coli TolC was grown in the presence of Carolacton. This was done to identify transcriptional regulatory networks that are directly affected by treatment of the strain with Carolacton. In order to gain insights into the primary transcriptional response, early time-points were chosen for sampling, which should not reflect secondary responses (e.g. due to differences in growth phase, nutrient depletion etc.). For each of the four examined time-points (0, 5, 15, 30), two biological replicates of Carolacton-treated and untreated samples were collected.