Micro: exotoxins

Question 1

inactivate elongation factor (EF-2)

-two bacteria

Answer 1

(1) Diptheria toxin

2) exotoxin A (psuedomonas aeruginosa

Question 2

inactivates 60S ribosome by removing adenine from rRNA

-two bacteria

Answer 2

(1) Shiga toxin
(2) Shiga-like toxin (EHEC)

these enhance cytokine release… causing HUS

Question 3

overactivates adenylate cyclase (Increase cAMP) –> increased Cl- secretion in gut and H20 efflux

Answer 3

heat LABILE toxin of ETEC

Question 4

overactivates guanylate cyclase (increase cGMP) –> decrease resorption of NaCl and H2O in gut

Answer 4

heat STABLE toxin of ETEC

Question 5

mimics adenylate cyclase enzyme (increase cAMP)

Answer 5

edema factor (bacillus anthracis)

Question 6

overactivates adenylate cyclase (increase cAMP) by permanently activating Gs –> increase Cl- secretion in gut and H2O efflux

Answer 6

cholera toxin

Question 7

overactivates adenylate cyclase (increase cAMP) by disabling Gi –> impairs phagocytosis to permit survival of microbe

Answer 7

pertussis toxin (ADP- ribosylating A-B toxin)

Question 8

Pertussis toxin (ADP-ribosylating A-B toxin)
A does \_\_\_\_\_
B does \_\_\_\_\_

Answer 8

B (binding) component binds to host cell surface receptor

A (active) component ataches ADP-ribosyl to disrupt host proteins

Question 9

cleave SNARE protein required for neurotransmitter release (so NT is NOT released)
-two bacteria

Answer 9

(1) Tetanospasmin (clostridium tetani)
- toxin prevents release of inhibitory NT (GABA and glycine) in spinal cord
(2) Botulinum toxin (clostridium botulinum)
- toxin prevents release of stimulatory ACh

Question 10

phospholipase that degrades tissue and cell membrane (lyse cell membrane)

Answer 10

Alpha toxin (clostridium perfringens)
-degradation of phospholipid C --> myonecrosis (gag gangrene) and hemolysis

Question 11

porting that degrades the cell membrane (lyes cell membrane)

Answer 11

streptolysin O (strep pyogenes)

• contributes to B-hemolysis
• host antibodies against ASO toxin used to diagnose rheumatic fever

Question 12

bring MHC II and TCR in proximity to outside of antigen binding site to cause overwhelming release of IFN-y and IL-2 –> shock
-two toxins

Answer 12

(1) TSST-1 (staph aureus)

2) exotoxin A (strep pyogenes

Question 13

ENDOtoxin: LPS

• seen in gram (-)
• what are it’s actions?

Answer 13

(1) activates macrophage
- IL-1, TNF, nitric oxide
(2) activates complement
- C3a, C5a
(3) activates tissue factor
- coagulation cascade –> DIC