Micro: exotoxins Flashcards
inactivate elongation factor (EF-2)
-two bacteria
(1) Diptheria toxin
2) exotoxin A (psuedomonas aeruginosa
inactivates 60S ribosome by removing adenine from rRNA
-two bacteria
(1) Shiga toxin
(2) Shiga-like toxin (EHEC)
these enhance cytokine release… causing HUS
overactivates adenylate cyclase (Increase cAMP) –> increased Cl- secretion in gut and H20 efflux
heat LABILE toxin of ETEC
overactivates guanylate cyclase (increase cGMP) –> decrease resorption of NaCl and H2O in gut
heat STABLE toxin of ETEC
mimics adenylate cyclase enzyme (increase cAMP)
edema factor (bacillus anthracis)
overactivates adenylate cyclase (increase cAMP) by permanently activating Gs –> increase Cl- secretion in gut and H2O efflux
cholera toxin
overactivates adenylate cyclase (increase cAMP) by disabling Gi –> impairs phagocytosis to permit survival of microbe
pertussis toxin (ADP- ribosylating A-B toxin)
Pertussis toxin (ADP-ribosylating A-B toxin) A does \_\_\_\_\_ B does \_\_\_\_\_
B (binding) component binds to host cell surface receptor
A (active) component ataches ADP-ribosyl to disrupt host proteins
cleave SNARE protein required for neurotransmitter release (so NT is NOT released)
-two bacteria
(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
phospholipase that degrades tissue and cell membrane (lyse cell membrane)
Alpha toxin (clostridium perfringens) -degradation of phospholipid C --> myonecrosis (gag gangrene) and hemolysis
porting that degrades the cell membrane (lyes cell membrane)
streptolysin O (strep pyogenes)
- contributes to B-hemolysis
- host antibodies against ASO toxin used to diagnose rheumatic fever
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
(1) TSST-1 (staph aureus)
2) exotoxin A (strep pyogenes
ENDOtoxin: LPS
- seen in gram (-)
- what are it’s actions?
(1) activates macrophage
- IL-1, TNF, nitric oxide
(2) activates complement
- C3a, C5a
(3) activates tissue factor
- coagulation cascade –> DIC