week 4: lab 10 (Capsule staining)

Question 1

What are the major components of capsule formation?

Answer 1

-Glycocalyx
-Lies outside of the cell wall:
*If firmly attached → Capsule
*If loosely attached → Slime layer

Question 2

what are capsules composed of ?

Answer 2

made of glycocalyx
-polysaccharides (sugars)
-polypeptides (amino acids)

Question 3

what functions can capsules perform?

Answer 3

• harder to kill
  -serve as energy and water reserves
  -a means to evade the host immune system and phagocytosis
  -anchor or surface attachment mechanism (sticks to surfaces)

Question 4

what is the clinical significance of bacterial capsules?

Answer 4

-Resistant to desiccation
○ Act as a way to store energy and water
-Slime layers evade immune system cells (phagocytes)
○ Not susceptible to phagocytosis
-Adhere to surfaces
○ Teeth
○ Urinary catheters
○ Metal pacemakers

Question 5

What two things should NEVER be done in capsule staining?

Answer 5

-DO NOT heat fix
-DO NOT rinse the slide with water

Question 6

capsule staining: what is the primary stain and its function?

Answer 6

Safranin or crystal violet
- Stain the cell and the background

Question 7

capsule staining: what is the decolorizer and its function?

Answer 7

20% Copper Sulfate
-Counterstain removing excess dye from the capsule but leaving the cell stained
- Will make the capsule have a faint blue hue

Question 8

Why is heat fixing not used in capsule staining?

Answer 8

Heat will destroy the capsule, preventing visualization

Question 9

what are the steps for capsule staining?

Answer 9

1. use a dry slide
2. add loophole of culture to slide (then smear)
3. air dry (DONT HEAT FIX)
4. cover with primary stain (safranin or crystal violet)
5. rinse with copper sulfate (NOT WITH WATER)
6. Blot dry the slide

Question 10

What are the results after capsule staining?

Answer 10

• the stain will color the cell and background either pink (safranin) or purple (crystal violet) the capsule will appear uncolored or light blue.