Quantitative Super-Resolution Imaging of Small RNAs in Bacterial Cells.

We present a method for the quantification of small regulatory RNAs (sRNAs) in bacteria, by combining single-molecule fluorescence in situ hybridization (smFISH), super-resolved single-fluorophore microscopy, and clustering analysis. Compared to smFISH imaging with diffraction-limited fluorescence microscopy, our method provides better quantification for short and abundant RNA (such as sRNAs) in a small volume of bacterial cells. Our method can also be directly used for the quantification of messenger RNAs (mRNAs).