Capsule and Biosynthesis

Question 1

Where are Capsules found

Answer 1

Outside outer membrane

Question 2

What does the D-glutamic acid capsule cause?

Answer 2

Anthrax disease

Question 3

What bacteria causes Anthrax disease?

Answer 3

Bacillus anthacis

Question 4

Serotype

Answer 4

Distinguishable strain

Question 5

What does the polysaccharide capsule allow?

Answer 5

Adherence to respiratory tissue

Question 6

2 antigen types on surface of bacteria

Answer 6

O and K antigen

Question 7

O antigen, how many varieties?

Answer 7

lipopolysaccharide - 9 varieties

Question 8

K-antigen, how many serotypes?

Answer 8

capsular polysaccharide - 80 serotypes

Question 9

Hypervirulent

Answer 9

Highly harmful

Question 10

What happens when a cell lacks a capsule?

Answer 10

No pneumonia

Question 11

What is the effect of a laboratory culture?

Answer 11

Loss of capsule

Question 12

What does the virulence factor allow bacteria to achieve?

Answer 12

• Colonization (movement + attachment to host)
• evade/inhibit immune response
• enter/exit cell
• obtain nutrition from host

Question 13

Advantages of Capsule

Answer 13

• surface attachment
• avoids immune response/detergents
  -protection in natural environments (dehydration)

Question 14

Homopolymer

Answer 14

Single repeating unit

Question 15

Heteropolymer

Answer 15

More than 1 elementary unit repeated

Question 16

H antigen

Answer 16

flagella

Question 17

Protective mechanism of capsule

Answer 17

inability of immune system to recognize via inhibition of complement and alternative pathway

Question 18

6 Steps of Wzx-Wzy pathway

Answer 18

1. making individual sugars
2. assembled onto lipid anchor on cytoplasmic side inserted to IM
3. Flip to periplasmic space (Wzx)
4. Polymerization (Close interaction of Wzx and Wzy)
5. Translocation through periplasmic space
   a. allow polar carbs to translocate
   b. entry point near IM
6. Linkage + attachment to phospholipid

Question 19

Polymerase

Answer 19

long chain polymerization

Question 20

OPX

Answer 20

OM periplasmic export

Question 21

PCP

Answer 21

Polysaccharide co-polymerase

Question 22

3 PArts of lipopolysaccharide

Answer 22

1. Lipid A
2. Core polysaccharide
3. O antigen

Question 23

Unique features of Lipid A

Answer 23

• 4 fatty acid chains
• KDO-core oligosaccharide

Question 24

Importance of LPS

Answer 24

• replaces most phospholipids in OM (protection from recognition)
• stabilizes OM structure

Question 25

LPS protection from:

Answer 25

• host defence
• bacteria-specific viruses

Question 26

LPS role in disease:

Answer 26

Lip.A –> endotoxin
-LArge doses = death

Question 27

LPS assembly steps 1-6

Answer 27

1. Individual sugars
2. Assembled on undecaprenyl diphosphate
3. Flip to periplasm (Wzx)
4. Polymerization (Wzy)
5. Translocation through periplasm and OM (PCP)
6. Linkage to Lipid A

Question 28

ABC transporter steps 1-6

Answer 28

1. Cytoplasmic synthesis of activated sugars
2. Polymerization/assembly
3. ATP binds + translocates across IM
4. Export w PCP/OPX proteins
5. Attachment to phospholipid/LipA