We standardized the zinc-imidazole negative staining method for detecting chromosomal-sized DNA molecules separated by pulsed field minigel electrophoresis. The best experimental conditions were as follows: separating large DNA molecules in minigels of 0.4cm thickness, further incubating them with 40mM ZnSO4solution, and finally incubating them with 0.1 and 2M imidazole solutions successively. The lowest yeast cells/miniplug useful in DNA band detection was 3×107cells, as occurred with ethidium bromide-stained minigel. Electrophoresis patterns were visualized as colorless bands contrasting against a white background after illuminating the minigel with white light. This negative staining method is nontoxic and preserves the chemical integrity of the DNA molecules. © 2010 Elsevier Inc.
León, K., Riverón, A. M., Arencibia, O., & López-Cánovas, L. (2010). Zinc-imidazole negative staining of chromosomal-sized DNA molecules in agarose minigels. Analytical Biochemistry, 402(1), 96–98. https://doi.org/10.1016/j.ab.2010.02.038