Question

Questions What does the term "Acid Fa" mean? Are acid-Fast organisms Gram-positive or Gram- 2 Do your results indicate that endospores are acid-fast? Explain. 3 Why is it best to use "old" cultures for this staining procedure? 4 When you stain your Mycobacterium smegmatis, some of the cells are red and others are blue. What does tell you about your culture?

Answer 1

1. )Acid fast means that a bacteria having colour cannot be decolourised by acid after staining procedure. For example Mycobacterium

Acid fast mostly gram negative bacteria.

In case of Mycobacterium, Myclolic fatty acids chains in the cell wall that does not allow any kind of staining.

2). Endospores :-- These are rigid structures produced by some bacteria like Clostridium and can tolerated intense heat as well as dessication for a long time. We cannot disinfect it easily.

To see endospores, Stain is allowed for a considerable time to penetrate it's wall and then can see. So it means it will be acid fast because stain removal will not be easy because it has reached in deep in wall.

3). Old cultures has low nutrition level as well a low space for upcoming generation of microorganism. In case of bacteria, most of the endospores will be in such stressful condition. So, Keeping endospore staining in eyes, the old cultures will be best.