Alteration of global transcription by saccharin in Escherichia coli K12

We perform differential RNA-seq comparing a treatment with 1.4% saccharin to a mock treatment in E. coli K12 in order to describe the alterations in global transcription produced by this artificial sweetener. Three biological replicates of saturated E. coli K12 cultures were diluted 1/100 in 25 mL LB medium (in duplicate, to obtain 3 treated cultures and 3 mock controls). The cultures were grown (37 ºC, 180 rpm) to approximately OD600 0.3 and they were treated with a final concentration of 1.4% saccharin or a water control. The cultures were further incubated until reacing OD600 0.8. At this point, cells were harvested, treated with RNAlate for preservation of total RNA and stored at -80 C. After that, total RNA was extracted from each sample. As a result, 305 genes appeared upregulated by the saccharin treatment, whereas 419 were downregulated. Overall design: Three biological replicates of saturated E. coli K12 cultures were diluted 1/100 in 25 mL LB medium (in duplicate, to obtain 3 treated cultures and 3 mock controls). The cultures were grown (37 ºC, 180 rpm) to approximately OD600 0.3 and they were treated with a final concentration of 1.4% saccharin or a water control. The cultures were further incubated until reacing OD600 0.8. At this point, cells were harvested, treated with RNAlate for preservation of total RNA and stored at -80 C.