Lugol's iodine solution (Gram stain)

Lugo's iodine solution, also called Lugo's iodine solution (Lugo1s iodine solution), is a reagent in Gram staining. It is often combined with crystal violet staining solution to stain bacteria; it is also used to detect starch in leaves, food and other samples. Starch with different degrees of polymerization can be dyed black or blue-black; when used in cell staining, it can color the cell nucleus to thereby Easier to observe. Gram staining is a widely used identification staining method in bacteriology. After primary dyeing with crystal violet and mordant with iodine solution, a water-insoluble complex of crystal violet and iodine is formed in the cell wall. Gram-positive The bacterial cell wall is thicker, the peptidoglycan network has many layers and is densely cross-linked. When the decolorizing solution is decolorizing, the peptidoglycan is dehydrated and the pore size is reduced, so the crystal violet-iodine complex is retained in the cell wall and appears purple. Gram-negative bacteria have thin cell walls, high lipid content in the outer membrane layer, thin peptidoglycan layer and poor cross-linking degree. After decolorization, the lipid outer membrane dissolves rapidly, the gap increases, and the crystal violet and iodine complex dissolves, thus decolorizing Later, it was counterstained with safranin and turned red.