Bacterial toxins Flashcards
Bacillus anthracis
Toxin: Anthrax toxin
-A tripartite (three- subunit) protein that consists of PA, EF and LF.
Toxin Structure: 2A+B
Effect: Disrupts cell signaling, cell migration, and cell death
Bacillus anthracis
Toxin: Protective antigen (PA)
Toxin structure: B subunit
Effect: Cell-binding domain
Mechanism: Facilitates the entry of either edema factor or lethal factor
Bacillus anthracis
Toxin: Edema factor (EF)
Toxin structure: A subunit
Effect: Edema (swelling)
Mechanism: Calmodulin-dependent adenylate cyclase; increases cAMP in target cells. This results in localized edema.
Bacillus anthracis
Toxin: Lethal factor (LF)
Toxin structure: A subunit
Effect: Pulmonary edema; anti-phagocytic
Mechanism: Zinc-dependent protease that cleaves a host signal transduction molecule.
Bordetella pertussis
Toxin: Adenylate cyclase toxin
Toxin Structure: AB
Effect: Antiphagocytic; inhibits and kills leukocytes
Mechanism: Calmodulin-activated adenylate cyclase causes an increase in target cell cAMP levels and a decrease in ATP production. This modifies cell function, resulting in the death of the cell.
Bordetella pertussis
Toxin: Pertussis toxin
Toxin Structure: A+5B
Effect: Many hormonal effects
Mechanism: ADP ribosylation of signal transducing G proteins blocks signal transduction
Bordetella pertussis
Toxin: Tracheal cytotoxin
Effect: Kills cilia-bearing cells
Campylobacter jejuni
Toxin: Enterotoxin
Toxin structure: A+5B
Effect: Diarrhea
Mechanism: ADP ribosylation of signal transducing G proteins blocks signal transduction
Clostridium botulinum
Toxin: Botulin (Neurotoxin)
Syn: botulinum toxin
Toxin structure: AB
Effect: Flaccid paralysis
Mechanism: Cleavage of neuromuscular presynaptic proteins blocks presynaptic junctions. This results in the decreased release of acetylcholine (a neurotransmitter).
Clostridium difficile
Toxin: Enterotoxin
Effect: Hemorrhagic diarrhea
Mechanism: Acts at the membrane
Clostridium difficile
Toxin: Cytotoxin
Toxin structure: AB
Effect: Cells lose filaments
Clostridium species
Toxin: α-toxin
Effect: Necrosis in gas gangrene; cytolytic; lethal
Mechanism: Phospholipase C
Clostridium species
Toxin: β-toxin
Effect: Necrotic enteritis
Clostridium species
Toxin: Enterotoxin
Effect: Food poisoning; diarrhea
Mechanism: Cytotoxin; damages membranes
Clostridium tetani
Toxin: Tetanospasmin (Neurotoxin)
Syn: Tetanus toxin
Toxin Structure: AB
Effect: Spastic (rigid) paralysis
Mechanism: Cleavage of synaptobrevin prevents the release of gamma-aminobutyric acid (GABA) and glycine (both are neurotransmitters) from the synapses of inhibitory neurons.
Corynebacterium diptheriae
Toxin: Diphtheria toxin
Toxin structure: AB
Effect: Cytolysis (cell death); Kills cells
Mechanism: ADP ribosylation of elongation factor 2 results in the inhibition of protein synthesis.
Escherichia coli
Toxin: Heat-labile enterotoxin
Toxin structure: A+5B
Effect: Diarrhea
Mechanism: Identical in action to cholera toxin
-ADP ribosylation of adenylate cyclase results in its activation. This results in an increase in cAMP levels in a cell.
Escherichia coli
Toxin: Cytotoxin
Effect: Hemorrhagic colitis
Mechanism: Identical in action to Shiga toxin
-Inactivates 60S ribosome, thereby preventing protein synthesis.
Escherichia coli
Toxin: Heat-stable enterotoxin
Effect: Diarrhea
Mechanism: Activates host guanylate cyclase
Legionella pneumophila
Toxin: Cytotoxin
Effect: Cytolysis (cell death); Lyses cells
Listeria monocytogenes
Toxin: Listeriolysin
Effect: Cytolysis (cell death); Lyses cells
Mechanism: Membrane damage; similar in action to streptolysin O
Pseudomonas aeruginosa
Toxin: Exotoxin A
Toxin structure: AB
Effect: Cytolysis (cell death); Kills cells
Mechanism: Similar in action to diphtheria toxin
Pseudomonas aeruginosa
Toxin: Type III cytotoxins
Effect: Modulate host cell physiology
Mechanism:Inhibits actin cytoskeleton
Salmonella enterica serovars (subspecies)
Toxin: Type III cytotoxins
Effect: Modulate host cell physiology
Mechanism: Alters actin cytoskeleton
