Staining of RNA and DNA on electrophoretic gels and in cytology with juice of Vaccinium myrtillus berries.

BACKGROUND: My early results of cytological chromosome staining with berry juice of blueberry or bilberry (Vaccinium myrtillus) was re-evaluated with staining of electrophoretic agarose and polyacrylamide gels, fractionating DNA, RNA, and proteins. RESULTS: Electrophoretic gels were stained with juice from berries of V. myrtillus, only filtered, or the diluted filtrate was mixed with acetic acid and 2-propanol. The staining starts in 2 min, with the highest intensity over the background usually appearing in about 30 min. The berry juice stains RNA, DNA, and an unidentified contaminant of molar mass 200-700 g. After differentiation of the gel background, the stained zones appear purple or black. The berry juice staining with or without acetic 2-propanol shows sharp RNA and DNA zones on gels in Vis (visible) light, and the berry juice displaces a preceding staining with ethidium bromide. A secondary staining with ethidium bromide is not able to displace the berry juice in nucleic acids. Cytological staining of sectioned mature barley (Hordeum vulgare) grains with Vaccinium myrtillus juice followed by differentiation in dilute acetic acid shows nuclei and apparent RNA storing compartments in the aleurone cells and stains suberin-containing chalazal cells of the grain crease deeply red, which keeps long. The anthocyanins faintly stain some proteins on gels. The preparation of polymers from cytochrome c and myoglobin was described. CONCLUSIONS: The staining molecules of V. myrtillus anthocyanins apparently intercalate in the nucleic acids competing for the sites, which could be intercalated by ethidium bromide. The juice is suggested to have use in the exchange of intercalating toxic molecules from DNA and RNA, in the inactivation of viruses, and phytotherapy. The juice may have a use as a nontoxic stain in cytology.