Gram Staining

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Gram Staining of Bacteria
Since bacteria is really small microbiologist use stains to help them see bacteria more clearly under the microscope. Many of the stains they use color the bacteria cells directly and are called direct stains. Bacteria cells have a slightly negative charge while direct stains have a slightly positive charge that helps the stain bin to the bacteria. The strength of the binding from the stains depends on the make-up of the cell wall itself.

Gram staining is the most helpful type of staining because it tells the difference between what types of bacteria. Most bacteria are divided into two groups depending on the type of cell walls they have. Bacteria can either have Gram (+) of Gram (-) cell walls. In the 1884 this staining procedure was developed by the Danish microbiologist, Christian Gram. When you expect the bacteria under a microscope Gram positive organisms will appear blue-black or purple. Gram negative organisms will appear red. Gram positive bacteria has a thick cell wall capable of grasping the violet dye. Gram negative bacteria has a thin cell wall.

In the Gram staining procedure first the bacteria is first heated to prepare them for staining they are stained using crystal violet. Then the stained cells are treated with iodine, this helps the crystal violet stain to the cell walls. The iodine is then washed away and the cells are treated with alcohol. The Gram negative will allow the violet stay to be washed away by the alcohol. On the other hand the Gram positive will resist the alcohol. Their cell walls retain the violet stain even after the alcohol treatment.

Gram negative bacteria is more dangerous the Gram positive bacteria. Gram negative bacteria’s outer membrane’s isn’t easily noticed by the human’s body. Gram positive bacteria is easier to attack usually by penicillin. Gram positive and Gram negative act differently to physical and chemical agents.
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