Figure 4

DNA contamination detection. Agarose gel separation of PCR products. For each of the six described methods, 20 ng of RNA from 4 different RNA extractions were used to perform PCR (using the "ftsZ sense" and "ftsZ antisense" primers). Resulting products were analysed after 25 (A) and 36 (B) cycles of PCR. Lanes M – double stranded DNA molecular weight markers (GeneRuler 100 bp DNA Ladder, Fermentas). To different extents, all extractions showed signs of genomic DNA contamination.