I tried to perform plasmid profiling. Plasmid DNA was isolated from several samples using commercial plasmid DNA extraction kit.
Extracted DNA was checked spectrophotometrically on nanodrop. The yield was from 60 to 80ng/ul, depending on a sample.
I prepared agarose gel electrophoresis (0.5% of agarose) according to the method presented in several publications. It was stained with EtBr.
The catch is that besides the molecular size markers I didn't have any bands or smears on the gel. Nor anything visible in the wells or throughout the lanes. No residues of chromosomal DNA either. Nothing for the tested samples.
My question is why? Has my plasmid DNA denatured to single stranded and is not visible under EtBr staining? Or maybe it's the wrong staining method I applied?
Thank you in advance for your suggestions.