Toxins L3

Question 1

What do toxins do?

Answer 1

Directly damage the host in specific ways

Question 2

What is the purpose of toxins? (3)

Answer 2

• Obtain cell associated nutrients
• Facilitate dissemination (spreading)
• Interfere witt host defenses

Question 3

What are the tasks of pathogenic bacteria? (4)

Answer 3

1. Encounter and enter the host
2. Establish an infectious niche
3. Multiply and cause damage
4. Spread to other tissues, hosts or both

Question 4

What are the factors responsible for pathogenecity? (4)

Answer 4

1. Colonization factors
2. Survival factors
3. Factors that cause damage or spread
4. Regulatory factors

Question 5

Define TOXIN

Answer 5

Protein that damages eukaryotic cells

Question 6

What is an exotoxin?

Answer 6

Classical toxin –> secreted by bacteria

Question 7

What is an endotoxin?

Answer 7

Non proteinaceous lipopolysaccharide of gram - bacteria (potent)

Question 8

What is Botulism?

Answer 8

• Obligate anaerobe (cannot grow in presence of O2)

- Gram + spore forming bacillus

Question 9

What does botulism cause?

Answer 9

Flaccid Paralysis

Question 10

Is Botulism an intoxication or infection?

Answer 10

Intoxication: does not grow in you

Question 11

What are the two mechanisms of action of Botulinum toxin?

Answer 11

1. A toxin

2. B toxin

Question 12

Describe the A toxin

Answer 12

1. Enzymatically Active
2. Translocated by the B domain
3. Protease that prevents Ach to be released
4. Cleaves proteins involved in synaptic vescicle fusion

Question 13

Describe the B toxin

Answer 13

1. Cell Binding
2. Recognizes target cells
3. RME
4. Acidification=membrane insertion

Question 14

What is Tetanus?

Answer 14

• Spore forming olbigate anaerobe
• Gram +
• Bacillus

Question 15

What does tetanus cause?

Answer 15

Causes spastic (NOT FLACCID) paralysis

Question 16

How does tetanus function?

Answer 16

Enter a wound, germinate and produce toxin

Question 17

How is tetanus similar to botulinum?

Answer 17

Poisons NT release by cleavage of proteins involved in vescicle fusion

Question 18

Describe FLACCID paralysis

Answer 18

• Botulinum toxins –> translocated to PERIPHERAL NERVES
• Prevent release of STIMULATORY NT like Ach
• Muscles cannot be stimulated to contract (at neuromuscular junctions [NMJ])

Question 19

Describe SPASTIC paralysis

Answer 19

• Tetanus toxin is translocated at CNS
• Prevents release of INHIBITORY NT like GABA
• Cannot TURN OFF contraction of muscle

Question 20

What is cholera?

Answer 20

• Gram negative
• Comma shaped
• Faculatative anaerobe (can be in presence or absense of O2)

Question 21

How does one acquire cholera?

Answer 21

Contaminated food or water

Question 22

What does cholera cause?

Answer 22

Large volume of watery diarrhea (can be fatal)

Question 23

What does the cholera toxin target?

Answer 23

G protein that controls [cAMP]

Question 24

What happens when cholera toxin is involved with its target?

Answer 24

Decrease in Na absorption
Decrease in water uptake
Increase in Cl- secretion
Losing a lot of water in body