Question

Which of the following is a vital dye?
A. Janus green B
B. Methylene blue
C. Neutral red
D. All of the above

Answer 1

Hint:- Vital sign is a technique in which a harmless dye is used to stain a living tissue(without killing them) for observation under a microscope. The stain can be injected into the tissues or the tissues can be immersed in the dye solution. It is also called biological staining. It is used for highlighting the microscopic cellular structures.

Complete answer:-
Janus green B is a type of basic dye which is in histology. It is used to stain the mitochondrial matrix. The Janus Green B also acts as an indicator and changes color according to the presence or absence of oxygen. (When oxygen is present, the indicator oxidizes and turns into a blue colour solution.
Methylene blue, also known as methylthioninium chloride is also a type of basic thiazine dye that is used to stain nucleic acids and chromatin material, and other nuclear structures of the cell. It works by converting the ferric iron in hemoglobin to ferrous iron. It is a medication and dye as a medication, it is used to treat methemoglobinemia. Neutral red is a eurhodin dye which is used to stain lysosomes present inside the cell red. It is used to stain embryonic tissues, Golgi apparatus in cells, and Nissl granules in neurons.
Thus, the right option is D.

Note:- Different stains stain different cell organelles and this property is used to stain the specific part. Methylene blue is used for animal cells like cheek cells while neutral red is usually used as a counterstain in combination with other dyes.