Microbiology: Exotoxins Flashcards
(24 cards)
What is the exotoxin for Corynebacterium diphtheriae?
Diphtheria toxin: inactivates elongation factor
What is the exotoxin for pseudomonas aeruginosa?
- Exotoxin A: inactivates elongation factor
- Mechanism: host cell death
Which exotoxins inhibit protein synthesis?
- Diphtheria toxin: corynebacterium diphtheria
- Exotoxin A: pseudomonas aeruginosa
- Shiga toxin: Shigella Shiga-like toxin: EHEC
Which exotoxins inactivate elongation factor?
- Diphtheria toxin (corynebacterium diptheriae)
- Exotoxin A (pseudomonas aeruginosa)
Which exotoxins inactivate the 60s ribosome by removing adenine from RNA?
Shiga toxin (Shigella) and shiga like toxin (EHEC)
What is the exotoxin for Shigella?
Shiga toxin: inactivates 60s ribosome by removing adenine from rRNA
What is the exotoxin for EHEC?
Shiga like toxin: inactivates 60s ribosome by removing adenine from rRNA
Which exotoxins increase fluid secretion?
- Heat-labile toxin (ETEC): overactivates adenylate Cyclase (increases cAMP) leading to increased Cl- secretion in the gut and H2O efflux
- Heat-stable toxin (ETEC): overactivates guanylate cyclase (increases cGMP) leading to decreased resorption of NaCl and H2O in the gut
- Anthrax toxin (Bacillus anthracis): mimics adenylate cyclase leading to increased cAMP
- Cholera toxin (Vibrio cholerae): overactivates adenylate cyclase (increases cAMP) by permanently activating Gs leading to increased Cl secretion in the gut and H2O efflux
Which exotoxin mimics adenylate cyclase?
Anthrax toxin (Bacillus anthracis)
Which toxin overactivates adenylate cyclase and leads to increased chloride secretion in the gut and water efflux?
Heat-labile toxin (ETEC)
Which exotoxin overactivates guanylate cyclase leading to decreased resorption of NaCl and H2O in the gut?
Heat-stable toxin (ETEC)
Which exotoxin overactivates adenylate cyclase by permanently activating Gs leading to increased secretion in gut and water efflux.
Cholera toxin (Vibrio cholera)
Which exotoxin inhibits phagocytic activity?
Pertussis toxin (Bordetella pertussis)
Which exotoxin inactivates Gi leading to activation of adenylate cyclase leading to increased cAMP?
Pertussis toxin (Bordetella pertussis)
Which exotoxins inhibit release of neurotransmitter?
- Tetanospasmin (clostridium tetani)
- Botulinum toxin (clostridium botulinum)
Which exotoxins are proteases that cleave SNARE (soluble SNF attachment protein receptor), a set of proteins required for neurotransmitter release via vesicular fusion?
- Tetanospasmin (clostridium tetani)
- Botulinum toxin (clostridium botulinum)
Which exotoxin is a phospholipase (lecithinase) that degrades tissue and cell membranes?
Alpha toxin (clostridium perfringens)
Which exotoxin is a protein that degrades the cell membrane?
Streptolysin O (Streptococcus pyogenes)
What is the mechanism of alpha toxin (clostridium perfringens)?
Phospholipase (lecithinase) that degrades tissue and cell membranes
What is the mechanism of streptolysin O (streptococcus pyogenes)?
Protein that degrades cell membrane
Which exotoxins cross-links the beta region of TCR to MHC Class II on APCs outside of the antigen binding site leading to overwhelming release of IL1, IL2, IFN-gamma, and TNF-alpha, leading to shock?
- Toxic shock syndrome toxin (Staphylococcus aureus) 2. Erythrogenic toxin A (streptococcus pyogenes)
What is the mechanism of toxic shock syndrome?
cross-links the beta region of TCR to MHC Class II on APCs outside of the antigen binding site leading to overwhelming release of IL1, IL2, IFN-gamma, and TNF-alpha, leading to shock
What is the mechanism of erythrogenic toxin (streptococcus pyogenes)?
cross-links the beta region of TCR to MHC Class II on APCs outside of the antigen binding site leading to overwhelming release of IL1, IL2, IFN-gamma, and TNF-alpha, leading to shock
What is this organism?
Histoplasma
- Presents as patient from the Mississippi-Ohio-Missouri river valleys with calcifying lung lesions
- Blastomyces also presents this way, but it is a broad-based budding yeast
