Finally studied with a Nobel technique the protein structure that shields and releases botulinum, bacterium toxin
Clostridium botulinum
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For the first time, the entire protein complex on which “travels” the botulinum toxin – the botulinum made sadly popular with the news of this summer – has been observed in detail.

A group of scientists from the University of Stockholm (in Sweden) used the Crio-Electronic microscopy, a microscope imaging technique that allows you to view the structures of the proteins with an unreachable precision, to study the molecular machine that protects and delivers neurotoxin produced by the bacterium to the body Clostridium botulinum.

Botulin: what is it?

Botulinic toxins are the most toxic known substances for man: as explained in the Guidelines for the correct preparation of food preserves in the home of the Istituto Superiore di Sanità (2016), a gram of pure toxin can cause the death of 14,000 people if taken by ingestion, 1,250,000 people per inhalation and 83,000,000 per injection.

The best known microorganism among botulinum producers is the Clostridium botulinuma bacterium widely present in the ground and in the waters, which can contaminate some foods with its spores.

The forms of botulism (the disease caused by the botulinum) food are mainly linked to vegetable preserves in which the foods have not reached sufficient acidification, often prepared at home following the family recipes: as the “neighborhood chemist” Dario Bressanini explains in a video dedicated to this theme, the less acidic environments in fact favor the proliferation of Clostridium botulinum (For the minimum safety regulations in the production and consumption of food preserves, we refer to the guidelines mentioned and the website of the Istituto Superiore di Sanità).

Botulinum: the symptoms

Food botulismo is a rare but potentially lethal pathology linked to the intake of botulinum. It manifests itself after 24-72 hours, and up to a week, from the ingestion of contaminated foods, with symptoms of variable gravity related to the amount of toxins taken, initially slight at the gastrointestinal level, and at a later time more alarming, such as cloudy of vision, inability to keep the eyelids (ptosis) open open, difficulty in articulating words and to swallow, dryness, dryness. In severe cases, facial paresis can be reached (symmetrical, unlike that caused by a stroke) and respiratory failure.

This second group of disorders is due to the fact that botulinic toxins damage the nervous transmission, causing a paralyzing effect that ceases only when administering the patient anti -xin, which neutralize the substances produced by the bacterium.

A complex structure

Pål Stenmark, professor of neurochemistry of the University of Stockholm and director of new research, specifies that “in nature, the toxin (botulinum) does not act alone.

It travels within a large protein complex made of 14 parts, that the fencing from the hostile environment of the digestive tract and helps her to go from the intestine to the blood, where the toxin is released and is free to circulate until it finds its goal, that is, the connection between the nerves and the muscles “.

Swedish scientists have studied the structure of the toxin by isolating it from a myiorilassant drug for the treatment of the stiff (neurobloc), closely similar to the botox that is used to temporarily relax the facial muscles and mitigate wrinkles in aesthetic medicine. Thanks to the Crio-Electronic Microscopy, a technique awarded in 2017 with the Nobel For Chemistry, the group obtained thousands of views of verses of the molecules, which were then combined in a 3D image with an almost atomic resolution.

New drugs (and antibodies)

The discovery, published on Science Advancescould reveal new strategies to neutralize this substance through antitoxins (i.e. antibodies that combine toxins by depriving them of the ability to do damage), or even expand their use for therapeutic purposes. In addition to aesthetic medicine, botulinum toxins are used in the pharmaceutical field for the treatment of some neurological conditions.