A simple methodology for RNA isolation from bacteria by integration of formamide extraction and chitosan-modified silica purification.

RNA isolation from bacteria is technically difficult due to the RNA characteristic of labile and vulnerable degradation. Many reagents were explored for cellular lysis and complete inhibition of RNase. However, the available methods for RNA isolation are either of low efficiency or time-consuming. Here, we developed a rapid and accessible protocol for RNA isolation that combined a simplified cell lysis and RNA release by formamide-based solution and RNA purification by chitosan-modified silica membrane for the first time. With this method, we obtained about ~ 28 μg of total RNA from 108 Escherichia coli cells. The entire procedure can be done within 15 min without redundant pipetting steps. The purity of extracted RNA was comparable to that of commercial kits, but the cost was much lower. Furthermore, the yielded RNA was successfully used in downstream enzymatic reactions, such as reverse transcription and quantitative real-time PCR. This new method would be of benefit for an extensive range of gene expression analyses in bacterial organisms.