Staining procedure in which only one stain is used and all types of bacteria appear as the color of the stain when viewed under the microscope
Simple stain
Simple stains can be used to determine a bacterial species’ ______ - ______ and ______.
morphology - shape and arrangement
A cationic dye which stains the cell a blue color
methylene blue
A cationic dye is ______ charged.
positively
With cationic dyes, the presence of ________ molecules in the cell like ____ and ____ causes the cell to stain.
negatively charged;
DNA and RNA
Common simple stain types include _____ stains, _____ stains, and ______ stains.
basic;
acidic;
negative;
High pH stains
Basic stains
Low pH stains
Acidic stains
Stains the surrounding cells instead of the cells themselves
Negative stains
What are the 6 basic stains?
- Methylene blue
- Crystal violet
- Malachite green
- Basic fuchsin
- Carbolfuchsin
- Safranin
What are the 4 acidic stains?
- Eosin
- Acid fuchsin
- Rose bengal
- Congo red
What are the 2 negative stains?
- India ink
- Nigrosin
What is the purpose of basic stains?
To stain negatively charged molecules and structures such as nucleic acids and some proteins
What is the purpose of acidic stains?
To stain positively charged molecules and structures such as proteins
What is the purpose of negative stains?
To stain the background; not the specimen
What is the outcome of a basic stain?
A positive stain
What is the outcome of an acidic stain?
Can be either a positive or negative stain, depending on the cell’s chemistry
What is the outcome of a negative stain?
A dark background with a light specimen
What 2 characteristics can be used to distinguish different types of bacteria?
Shape and arrangement
