1) If direct stains work so well, why would we ever use indirect stains? Give two reasons why you might choose to use indirect stains instead of direct stains? 2) Assume that two days (dye A and dye B) were applied to bacterial smear. The cells were stained by dye A while the slide background was stained with dye B. Which stain had an anionic chromogen? Which stain had a cationic chromogen?
Microscopic examination
The analysis of minute organisms, cellular organization of any biological structure, and composition of body fluids with the help of a microscope is known as microscopic examination. The magnification of specimens or samples under study helps in attaining a clearer picture of it.
Gram Staining
Named after Hans Christian Gram, a Danish bacteriologist, Gram stain is one of the most powerful staining techniques within microbiology. This technique was introduced in 1882 to identify pneumonia-causing organisms. The Gram staining technique uses crystal violet or methylene blue as primary staining colors to distinguish gram-positive from gram-negative organisms. Under a microscope, the gram-positive organisms appear purple-brown, retaining the primary color. Gram-negative organisms appear pink or red as they do not acquire the color of the primary stain.
1) If direct stains work so well, why would we ever use indirect stains? Give two reasons why you might choose to use indirect stains instead of direct stains?
2) Assume that two days (dye A and dye B) were applied to bacterial smear. The cells were stained by dye A while the slide background was stained with dye B. Which stain had an anionic chromogen? Which stain had a cationic chromogen?
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