How do you know if a Bacteria is Gram Stain negative or positive?
Neisseria is gram negative. Gram positive bacteria are those that are stained dark blue or violet by Gram staining, in contrast to Gram-negative bacteria, which cannot retain the stain, instead taking up the counterstain and appearing red or pink. The stain is caused by a high amount of peptidoglycan in the cell wall, which typically, but not always, lacks the secondary membrane and lipopolysaccharide layer found in Gram-negative bacteria. ————————————–… Gram staining procedure: 1. Make a slide of tissue or body fluid that is to be stained. Heat the slide for few seconds until it becomes hot to the touch so that bacteria are firmly mounted to the slide. 2. Add the primary stain crystal violet and incubate 1 minute. This step colors all cells violet. 3. Add Gram’s iodine, for 30 seconds. It is not a stain; it is a mordant. It doesn’t give color directly to the bacteria but it fixes the crystal violet to the bacterial cell wall. All cells remain violet. 4. Wash w
