For example, MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide] can be used to stain fungi for the presence of cytoplasmic and mitochondrial dehydrogenases. If the fungal colony is viable, a purple precipitate (formazan) will be formed. If the colony is dead, it will not convert MTT to formazan.
Of course there are also many cell organelle-specific dyes that work well for many fungi and can be analyzed by fluorescence microscopy: DAPI, Hoechst (nuclear DNA), Mitotracker Red, Mitotracker Green FM, DASPMI (mitochondria), FM 4-64, MDY-64 (vacuole membranes), calcoflour (cell walls, septae), etc.
lactophenol cotton blue stain is good for identification mold
you can prepared according to Ellis (1994) from the following ingredients:-
Cotton Blue (Aniline Blue) 0.05 g
Phenol 2 g
Glycerol 40 ml
Lactic acid 20 ml
Distilled water 20 ml
Which were prepared by dissolving the cotton blue in the distilled water, then left to stand overnight to eliminate insoluble dye. The phenol crystals was added to the lactic acid in glass beaker, and with the aid of magnetic stirrer, the phenol was dissolved, then the glycerol was added, the cotton blue was filtered into the (phenol – glycerol – lactic acid) solution, after mixing, it was stored at room temperature to be used for staining and microscopic identification of fungi.
Lactophenol cotton blue blue is convenient for day to day use. It is known to be most commonly used for microscopic study of fungi. For selective study you can make use of other strain as given by above workers as per your requirement.
Lactophenol cotton blue can be easily made in your lab or you can purchase ready made also like HighMedia (S016) and other suppliers.