Exotoxins Flashcards Preview

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Flashcards in Exotoxins Deck (14):
1

C.diphtheriae

inhibits protein synth by inactivating EF-2
diphtheriae toxin

2

Pseudomonas aeruginosa

inhibits protein synth by inactivating EF-2
exotoxin A (attaches to ADP-ribosyl) [part of exotoxin AB, w/ B = binding component]

3

Shigella

Shiga toxin
inhibits protein synth by inactivating ribosome by removing ADENINE from rRNA
invades host cells!

4

EHEC (O157:H7)

Shiga-like toxin
inhibits protein synth by inactivating ribosome by removing ADENINE from rRNA
does NOT invade host cells!

5

ETEC

LT (heat labile) - overactivates ADENYLATE cyclase (increases cAMP) --> increase Cl secretion in gut + H2O efflux

ST (heat-STABILE) - overactivates GUANYLATE cyclase (increases cGMP) --> decreases resorption of NaCl and H2O in gut

6

B.anthracis

edema factor
MIMICS adenylate cyclase (increase cAMP)

7

V.cholerae

cholera toxin
overact. adenylate cyclase by PERMANENTLY ACTIVATING Gs --> increase Cl secretion in gut + H2O efflux
same Cl channel used in CFTR gene

8

B.pertussis

pertussis toxin
overact. adenylate cyclase by DISABLING Gi (increased sensitivity to histamine) and impairing phagocytosis!

9

C.tetani

tetanospasmin
prevent release of INHIBITORY NT (GABA, glycine) by cleaving SNARE protein

10

C.botulinum

botulinum toxin
prevent release of STIMULATORY NT at NMJ (ACh) by cleaving SNARE protein

11

C.perferingens

alpha toxin (lecithinase)
phospholipase (DEGRAD OF PHOSPHOLIPASE C) that degrades tissue and cell membranes

enterotoxin - food poisoning

12

S.pyogenes

Streptolysin O
degrades cell membrane (causes RBC LYSIS)

Exotoxin A (superantigen)
bind MHC II and TCR simultaneously --> POLYCLONAL expansion of T-cells --> overwhelming release of IFN-gamma and IL-2 --> shock!

13

S.aureus

TSST-1 (superantigen)
bind MHC II and TCR simultaneously --> POLYCLONAL expansion of T-cells --> overwhelming release of IFN-gamma and IL-2 --> shock!

exfoliative toxin - SSS

enterotoxin (preformed) - food poisoning

14

Yersinia toxin

increase cGMP by activating guanylate cyclase