Microbiology Lesson 6 Flashcards
Using a series of dyes and additional chemicals to stain bacteria in contrasting colors based on structural difference between bacterial cells.
Differential Stain
3 Types if Stain
Gram stain
Acid-fast stain
Endospore stain
by Christian Gram (1800’s); the first differential staining technique in use and is still an important tool for distinguishing between two main types of bacteria.
Gram Stain
Nearly all bacteria contain peptidoglycan, a molecule unique to the___________?
bacterial cell wall
2 Main Types of Bacteria
Gram-positive (purple staining) & Gram-negative (pink staining)
bacteria have a cell wall composed almost entirely of peptidoglycan, present in many layers.
Gram-positive (purple staining
bacteria have a cell wall with only a thin layer of peptidoglycan beneath an outer cell wall membranous layer composed of lipopolysaccharides(LPS), an endotoxin that can be harmful to organisms infected with Gram-negative bacteria.
Gram-negative (pink staining)
This distinction is due to differences in the bacterial cell wall structure of these two categories of bacteria and has significance with respect to which antibiotics can be used to kill or control bacteria.
Cell Wall of Mycobacteria and Nocardia
used to identify specialized bacteria that have waxy mycolic acid in their cell wall.
Acid-fast Stain (Ziehl-Neelsen stain)
bacteria that possess mycolic acid
Acid fast
do not have cell walls containing mycolic acid
Non-acid fast
The presence of mycolic acid in bacteria is rare, only found in two genera?
Mycobacteria and Nocardia
are kind of like “bacteria seeds”, made through a process known as sporulation in response to extreme environmental conditions, such as high temperatures, desiccation (drying out), chemicals, changes in pH and lack of food.
Endospore Stain
