Chapter 10, Problem 1Q

Which two stains done in this experiment are differential stains?

Summary Introduction

To determine:

Two differential stains used in the given experiment.

Introduction:

Differential stains are the stains that require two different stains to distinguish between two groups of microorganisms or two different cell structures. This means, by differential stain difference between encapsulated and non-encapsulated cells can be seen.

Explanation of Solution

Gram stain is a staining method that helps in the differentiation of gram-negative bacteria and gram-positive bacteria, by determining the physical and chemical properties of their cell wall. Crystal violet stain is used in this test. Gram-positive bacteria have a high affinity for crystal violet when gram's iodine is applied on it. in this test, the decolorizing agent used is acetone or ethyl alcohol. Acetone gets dissolved in the lipids of the cell wall of the gram-negative bacteria, which leads to the leaking out of the crystal-violet complex from the thinner peptidoglycan layer.

The acid-fast stain is used to differentiate between acid-fast bacteria and non-acid fast bacteria. The stain here is used carbol fuchsin, which is soluble in the lipoidal material found in the mycobacterial cell wall. The decolorizing agent used here is acid alcohol. These are the two differential stains used in the given experiment.

Conclusion

Two differential stains used in the given experiment are the gram stain test and acid-fast stain test.