Toxins Flashcards
Endotoxins
- Derived from lipopolysaccharide
- Cell wall of gram-negative bacteria, e.g.
- E.coli, Shigella dysenteria
Exotoxins
• excreted from viable organisms or
released when it lyses.
Staph. aureus, Clostridium spp.(botulinum, perfringens,
tetani), B. anthracis, etc.
[Usually gram- pos., but Vibrio cholera and
Pseudomonas aeruginosa can also produce
exotoxins]
Botulinum Neurotoxin
• Clostridium botulinum, an anaerobic sporeformer,
produces 7 distinct toxins. A,B,E, and F are most
often implicated in human disease.
• Most potent neurotoxin. Causes life threatening
paralysis.
• Major risks: aerosols and needlesticks. Can be
absorbed through non-intact skin.
• Readily inactivated by 0.1% NaOCl and 0.1N NaOH.
• IND vaccine available from CDC
Staphlococcal Enterotoxins
• Produced by Staph. aureus.
• Important cause of food poisoning and toxic shock
syndrome
• Transmission in lab has occurred through accidental
ingestion, needlesticks, inhalation and mucous
membrane contact
• Toxins may be present in clinical samples, and fluids
and tissues from exposed animals
• Can persist on surfaces
Ricin Toxin
- Ricin is produced in maturing seed from castor bean
- Much less toxic than BoNT and SE
- Ingestion is seldom fatal, but inhalation and intravenous exposure are more problematic
- No vaccine or antidote
Rosary pea plant
abrin
cone snail
conotoxin
Marine dinoflagellates
saxitoxin
Fusarium species
T-2 mycotoxin, diacetoxyscirpenol
Aspergillis species
aflatoxin
abrin
- Similar to ricin
- Used in medical research because of its potential as a treatment to kill cancer cells
- Powdered abrin is yellowish-white in color
- Abrin is a stable substance, meaning that it can last for a long time in the environment despite extreme conditions such as very hot or very cold temperatures.
- Abrin causes illness by getting inside the cells of a person’s body and preventing the cells from making the proteins they need. Without the proteins, cells die. Eventually this harms the whole body, and death may occur.
- Effects of abrin poisoning depend on whether abrin was breathed in, swallowed, or injected
Permissible toxin amount
Abrin
100 mg
Permissible toxin amount
Botulinum neurotoxins
0.5 mg
Permissible toxin amount
Short, paralytic alpha conotoxins
100 mg
Permissible toxin amount
Diacetoxyscirpenol (DAS)
1000 mg
