microbial toxins Flashcards
Toxin actions
- spread
- damage cell wall
- cytokin production
- protein synthesis
- intracellular pathways
- Inhibit release of NT
What toxin help spread? (5)
Hyaluronidase Collagenase Elastase Deoxyribonuclease Streptokinase
LIst 2 toxin damage cell walls
Hemolysins
cytolysins
How does toxin damage cell walls?
insert into membrane –> complex –> more/lyse
Name 2 cytokine production toxin
pryogenic exotoxins
Superantigens
How do super antigens work?
Bind MHC Class II and Vb on T cell –> antigen independent activation
2 toxin that inhibits protein synthesis
Diptheria toxin (and pseudomonas exotoxin) Shiga toxins
Diptheria toxin targets ___?
EF2 (inactivates)
ADP transfer from NAD to EF2
Shiga toxin targets ___?
28S (part of 60s)
Removes Adenine from 28S
Name the 6 toxin that modify intracellular signaling pathways
Heat labile of vibrio cholerae/E coli Pertussis toxin Heat stable enterotoxin ST1 Ecoli Anthrax edema factor Anthrax lethal factor C. difficile toxin A & B
C. Difficile toxin A causes ____
Diarrhea
C difficile toxin B affects ____?
Rho family GTPase (actin cytoskeleton)
glucosyl transferase: UDP - glu –> rho
Anthrax lethal factor targets ___?
(endopeptidase cleaves) MAP kinase kinase proteins (inactive signal transduction)
Anthrax edema factor causes
increase cAMP
adenylate cyclase toxin - need Ca2+ and calmodulin
Adenylate cyclase toxin requires _____ and _____ to activate
Calcium and calmodulin
Heat stable enterotoxin 1 (ST1) Ecoli targets is a ______ ______ and causes ______ to increase and ________
granylate cyclase; cGMP; secretory diarrhea
Pertussis toxin and heat labil enterotoxin (cholera and Echoli) is a ______________
ADP ribosyltransferase
Pertussis toxin causes G_ to be ______, which causes _____
Gi to be inactivated –> increase cAMP (increase secretion)
Cholera and heat labil ecoli toxin (enterotoxin) causes G_ to be ______, which causes _____
Gs to be active –> increase cAMP (increase secretion)
Name 2 toxin that inhibits release of neurotransmittors
botulinum toxin + tetanus toxin
botulinum toxin + tetanus toxin are ____________?
zinc - dependent endopeptidase
botulinum toxin + tetanus toxin inactivates _______ which causes the inability to _______
SNARE; neuroexocytosis
botulinum toxin causes ___ paralysis, vs tetanus toxin causes ___ paralysis
flaccid; spastic
botulinum toxin + tetanus toxin acts where? (different places)
Bot: at myoneural junction - inhibits release of Ach
Tet: at spinal cord - inhibits inhibitory interneurons
Toxins act _______ or on _______
extracellulary; plasma membrane
Toxins are typically bi functions… what are the two domains and fcn?
subunit A: Active
subunit B: binding
Toxins usually enter target cells by _______
endocytosis
Antitoxin functions?
bind to toxin - prevent toxicity - neutralization
Antitoxin does NOT do what? (2)
- prevent infection by bacteria
2. reverse toxic effect
Toxoids are derivatives of ____ and retains ______ but lack _____
toxins; immunogenicity; toxicity
Toxoid used for
active immunization vaccine
Passive immunization administrates _______ and are _____ protection against toxin/infectious agent
antibodies, temporary
Immunotoxin/hormonotoxins are
hybrid molecule: Toxin fragment + ligand
Uses of Immunotoxins
cancer, autoimmune, etc
