Introduction
Simple stain
The simple stain can be use to determine cell shape, size and arrangement. The simple stain is staining procedure involving only one stain. There stains will readily dive up a hydroxide ion, which leaves the stain positive charged. Since the surface of most bacterial cell is negatively charged.
Negative stain
The negative stain is particularly useful for determining cell size and arrangement. It can be used to stain cell that are too delicate to be heat-fixed. Nigrosin is an acidic stain. This means that the stain readily give up a hydrogen ion and become negative charged. Since the surface of most bacterial cell is negative charged, the cell surface repels the stain. The glass of the slide will stain, but the bacterial cell will not. The bacteria will show up as clear spots against a dark background
Gram Stain
The gram stain is the most important staining procedure in microbiology. It is used to differentiate between gram positive organisms and gram negative organism. It is differential stain. Gram negative and position organism are distinguished from each other by differences in their cell wall. These differences affect many aspects of the cell, including the way the cell take up and retains stains