A light microscope may be used to see and examine the vacuole's structure. While the vacuole doesn't stain as the other organelles of the cell (because it does not contain many constituents that stain) tests have demonstrated that staining is possible for this organelle because the vacuole's sap absorbs and stores dyes that are colored.
Papanicolaou stain can also be referred to as the pap stain, and the process that causes the stain is referred to as a pap smear.
Different stains have been developed over time to distinguish bacteria species, separating them morphologically and the specific characteristics they possess. The most popular stain is Gram staining, acid-fast staining, and endospore staining. Each stain aims at identifying and defining bacteria according to their forms and morphologies.