Which two staining techniques commonly employ a mordant to enhance staining?

• A. Gram stain and flagella stain
• B. Endospore stain and acid-fast stain
• C. Acid-fast stain and capsule stain
• D. Simple stain and negative stain

Answer: (A)

Verified step by step guidance

1. Understand the role of a mordant in staining: a mordant is a substance used to fix or intensify the stain by forming a complex with the dye, making it less soluble and more firmly attached to the specimen.
2. Recall the Gram stain procedure, which uses iodine as a mordant to form a complex with crystal violet, enhancing the retention of the primary stain in Gram-positive bacteria.
3. Consider the flagella stain, which uses a mordant to coat the thin flagella, increasing their diameter so they become visible under the microscope.
4. Review other staining techniques mentioned: endospore stain uses heat rather than a mordant, acid-fast stain uses heat and carbol fuchsin but also employs a mordant-like effect through the dye's affinity, while capsule and simple/negative stains do not typically use mordants.
5. Conclude by identifying the two staining techniques that explicitly use a mordant to enhance staining based on their protocols and the role of mordants in each.