Which of the below combinations can help in visualising DNA fragments in the gel electrophoresis process?
During the preparation of agarose for gel electrophoresis, appropriate amount of agarose is mixed with a running buffer (TBE: Tris borate EDTA) along with an intercalating dye EtBr (Ethidium bromide; 0.5 μg/ml conc.). By the time gel electrophoresis is completed, DNA takes up sufficient amounts of Ethidium bromide (EtBr) and when illuminated with ultraviolet light, it glows in fluorescent orange colour.
Safranin is a cationic dye which is used to study different tissues and cells to identify and distinguish them. Safranin is also used as counterstain staining protocols, colouring cell nuclei red.
Acetocarmine is a nonspecific nuclear stain which simply binds with the chromosomes and gives colour to them, acetocarmine is also used for studying the mitotic chromosomes.
Crystal violet binds to DNA and proteins so that it can detect the cell adherence(cells interact and attach to neighbouring cells). This dye can be used on live cells only and not on isolated DNA fragments. Amount of crystal violet dye taken by the cells tells us about the number of cell which are alive as cell adherence is not shown by dead cells.