Speedy Dissolution
This is the property of microorganisms that acid fast stains depend on?
Lipoid capsule and the ability of these organisms to resist decolorization with dilute acid
Gram + organisms will stain this color in the Brown-Hopps method
Blue-black
This is the recommended counterstain when PAS is used to demonstrate fungi
Light green
This could result in acid fast organisms that appear on slide, but slightly out of the plane of the section
Using contaminated tap water in the water bath
This component of the fungal cell wall makes it PAS positive
Carbohydrates
This fixative should be avoided for acid-fast stains as it could cause normally acid-fast tissues to stain negative
Carnoy
What is the difference between gram positive and gram negative bacteria?
The amount of peptidoglycan in the cell wall.
Stains for the demonstration of spirochetes are based on this property.
Argyrophilia
This error in the Gram staining process may cause the formation of insoluble compounds that are difficult or impossible to decolorize
Allowing the slides to dry at any step in the procedure
What are 3 different ways we classify bacteria?
shape, gram staining, and acid-fast staining.
What is the differentiator in carbol-fuchsin techniques?
Acid alcohol
This is the mordant for Brown-Hopps.
Crystal-violet/Iodine
How do acid Schiff stains (PAS or CAS) work to demonstrate fungi?
Carbohydrates in the fungal cell walls are oxidized by the acid into aldehydes which chemically bind with the Schiff reagent
This could cause chromic acid stained slides to turn brown
Not completely removing alcohol before placing slides in chromic acid
This step following Schiff reagent helps remove excess leucofuchsin
Rinsing with a sulfite solution
What type of water should be used when staining for acid-fast organisms and in which steps of histology?
Millipore-filtered water in the staining procedure if a water rinse is needed before Carbol-fuchsin is used
and in the flotation bath for microtomy
This is the name of a specific proprietary formula of the Romanowsky type stain that can be used to demonstrate microorganisms
Diff-Quik
Cryptococcus neoformans is unique compared to other yeastlike fungi due to its mucoid capsule, which means it can be demonstrated by these techniques
Those for acid mucosubstances like Mayer mucicarmine, Alcian blue, and Colloidal iron
This is the process for correcting slides that were overstained with methylene blue in the Kinyoun acid-fast stain
Back the sections up to acid alcohol, then re-counterstain
This specific component in the waxy layer of the bacterial cell wall is disrupted by Carnoy fixative, making acid-fast organisms stain non acid-fast
Mycolic acid
Why is peanut oil used in Fite staining?
Peanut oil protects the capsule and helps the organism resist decolorization.
If alcohol is used you will have negative staining due to the target organisms (M. leprae) not being alcohol-fast.
Why do we use measured amounts of azures in Romanowsky staining today?
Previously, the wide range of colors seen were due to impurities in the actual dye solutions. We use measured amounts of azures for more consistent staining results.
Why is hydroquinone used in the Warthin Stary technique?
It is an argyrophilic method, the spirochete can bind silver ions from the solution but can’t reduce the silver to a visible form, so hydroquinone is used as the chemical reducer.
Changing the time in this solution would help correct Brown - Hopps Gram stained slides with an intense red background
Picric acid-acetone differentiation
Grocott Methenamine Silver when used on the liver will prominently stain glycogen, causing a diffuse black stain that makes it difficult to see organisms. What could be done to prevent this?
Diastase digestion (Carbohydrates & Amyloids chapter)