Methylene blue

Definition

Methylene blue is a cationic dye used in microbiology for staining microscopic specimens. It binds to acidic components of cells, providing contrast for visualization under a microscope.

5 Must Know Facts For Your Next Test

1. Methylene blue is commonly used in simple staining techniques to visualize bacterial cell morphology.
2. It can penetrate the cell walls of bacteria, making it useful for distinguishing between different types of microorganisms.
3. The dye is positively charged and binds effectively to negatively charged cellular components like nucleic acids and proteins.
4. In Gram staining, methylene blue can be used as a counterstain if safranin is not available.
5. Methylene blue also has applications in differentiating between live and dead cells in viability assays.

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Related terms

Gram Staining:

A differential staining technique used to classify bacteria based on their cell wall composition.

Simple Stain: A method that uses a single dye to color cells and provide contrast for microscopic examination.

Counterstain:

A secondary stain applied after the primary stain in certain staining techniques to provide contrast.