Microbial toxins and mycotoxins Flashcards

1
Q

Endotoxin

A

LPS - specifically Lipid A

Causes release of cytokines

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2
Q

Endotoxin - clinical signs

A

fever, hypotension, loss of effective circulation

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3
Q

types of Exotoxins

A
bacterial proteins
Cytolytic toxins
Enzymes
Enterotoxins
Neurotoxins
Superantigens
ADP-ribosylation toxins
Type III secretion systems
Clostridial toxins - botulinum toxin
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4
Q

Cytolytic toxin - examples

A

Sometimes haemolysins - Streptolysin S of Strep equi

Sometimes not haemolytic, but still damage cells - leukocidins, ApxIII of Actinobacillus pleuropneumoniae

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5
Q

Enzymes - examples

A

Phospholipase C of Clostridium perfringens = alpha toxin

hyaluronidase, collagenase, protease, lipase

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6
Q

LT (labile toxin)

A

Similar to Cholera toxin.
Attaches to brush border of small intestinal cells
activates Cl channel - Na + water follow Cl out of cell

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7
Q

Neurotoxins

A

Botulinum toxin - blocks release of acetylcholine
at the synapse and neuromuscular junction.
Flaccid paralysis and death.

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8
Q

Tetanus toxin

A

Blocks release of neurotransmitters for inhibitory synapses - uncontrolled excitatory synaptic activity.
Paralysis by constant tensing of muscles - tetani.

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9
Q

Superantigens

A

Staphylococcus aureus TSST-1 protein.
Immunomodulators - induce massive T-cell activation &
cytokine release.
Toxin binds to invariable regions on MHC Class II on APC;
the normal process of T-cell activation is short-circuited.

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10
Q

Mycotoxins

A

Toadstool poisoning
Ingestion of plant pathogenic fungi (Ergotism)
Ingestion of moulded feed (Mycotoxicosis)

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11
Q

Ergotism or ergot poisoning

A

Sclerotium forms in grass & cereal

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12
Q

Ergotism or ergot poisoning - clinical effect

A

contain vasoactive alkaloids
constriction of arterioles in extremities → gangrene &
lameness. Also convulsions.
Halucinations & pain in humans

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