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After my very successful story yesterday, I decided to do a follow-up article on AB toxins as the toxin in the story, Botox, belongs to this group.
What is an AB toxin?
AB toxins are produced by bacteria. The “AB” refers to the fact that this group of toxin consists of two parts (A and B). The B part binds to the surface of a cell and then the toxin is absorbed. The A part is split from the B part and then acts toxic. That’s the basics.
made by me
Botulinum Toxin
Oh, our beloved Botox! Makes us look young again and has so many more uses. But it wasn’t like this from the beginning. Botulinum toxin is produced by the bacterium called clostridium botulinum and causes Botulism.
The toxin, once it has entered the cell, prevents neurotransmitter from being released in our muscles. This means we can’t move them and applies to any muscle. Botulism paralyses and you can die of suffocation.
Four kinds of botulism are known:
Foodborne botulism, usually because of food that went bad, especially canned food. The bacterium makes spores which are very heat resistant and thrive in environments low with a low oxygen content. Stay away from weird looking canned food.
by Jason Wilson
Infant botulism! This one is not directly caused by the toxin but by infants ingesting the spores which then germinate into bacteria. The bacteria then start producing toxins directly inside the children’s guts. For everyone over 6 months, this is usually not a problem. Under 6 months, it is. Don’t feed your babies honey.
Wound botulism is relatively rare. Keep your wounds clean.
Inhalation botulism doesn’t happen naturally but could be weaponized.
Tetanus
Tetanus is the little brother of Botox. It’s produced by a Clostridium bacterium too, but by Clostridium tetani. The spores can be found in soil and the intestines of animals and are usually transmitted through dirty objects that break the skin. If the umbilical cord is cut with a dirty knife, it can lead to a tetanus infection too.
The mechanism is the exact opposite of the one for botulinum toxin! Instead of causing a paralysis, tetanus toxin blocks neurotransmitters that are supposed to inhibit signals. This leads to a constant muscle contraction and … death.
by Charles Bell
Luckily, cases of infant deaths by tetanus reduced a lot between 1988 and 2013 (according to the World Health Organization). In 1988, about 787000 newborn babies died because of a tetanus infection, in 2013 it was just 49000.
Anthrax
Everyone’s favorite white powder, right after cocaine! This AB toxin is produced by Bacillus anthracis and it’s again the spores which are toxic. Breathe them in, eat them, get them in an open wound, it doesn’t matter. And an Anthrax infection isn’t pretty.
It’s actually two toxins, not just one, that work their magic. One causes an edema (a swelling) and one straight out kills the cells. I won’t put a picture of that in here, it looks very disgusting. But you’re invited to google it if you have the stomach!
Cholera
Would you rather have the plaque or cholera?
Vibrio cholerae is the bacterium that produces the cholera toxin and is usually found in dirty water. It enters intestine cells and causes chloride ions to rapidly leave the cell. As a result, water leaves the cell too because the concentration of chloride ions outside the cell is higher than the one inside the cell and the body usually doesn’t like huge concentration differences.
All that water that suddenly leaves the cells causes vomiting and extreme diarrhea. And when I say extreme I mean “can kill you within a few hours if nobody helps you”-extreme.
Luckily, most of the infected have only mild symptoms. Still, there are between 21000 and 143000 deaths because of it each year worldwide.
Diphtheria
I hope every one of you is vaccinated against Corynebacterium diphtheriae because otherwise, my great-grandmother will come over and kick your ass.
When she was a child, she almost died of diphtheria. Some of her friends did. She told me that she’s so glad I’ll never have to go through it.
The toxin isn’t really that interesting, it prevents the cell from producing proteins which kills the cell.
But the effects?
Weakness, sore throat, fever, a swollen neck, and death all don’t sound that pleasant.
In the USA, 15520 people died in 1921 of diphtheria. Between 2004 and 2005, there were only 2 cases at all and nobody died. Can I hear a “hell yeah!” for modern medicine?
That’s it, I hope it wasn’t too dry and you learned something interesting. Or maybe not. Maybe you just wasted some time. But you wasted time efficiently!
Sources:
Biology and Molecular Epidemiology of Diphtheria Toxin and the tox Gene
Cholera toxin: A paradigm of a multifunctional protein
Tetanus and botulinum neurotoxins: mechanism of action and therapeutic uses
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