To poison intestinal cells, E. coli needs a special sugar that a person cannot synthesize himself. It enters the body only with meat and milk. So for those who do without these products, intestinal infections are not threatened – at least those caused by the bacterium subtype Shiga.
Recent studies have shown that vegetarians are doing their job in vain: by refusing meat and dairy products, they reduce the likelihood of suffering from E. coli toxins of the Shiga subtype, which causes bloody diarrhea and even more terrible diseases, to almost zero.
It’s all about small sugar molecules: it turns out that the target for the toxin of this bacterium is N-glycolneuraminic acid (Neu5Gc), which is located on the surface of our cells. But in the human body, this signal sugar is not synthesized. As a result, bacteria have to “wait” for the Neu5Gc molecule to enter the digestive tract from meat or milk and integrate into the membrane of the cells lining the intestines. Only then does the toxin begin to act.
Scientists have demonstrated this with several in vitro (in vitro) cell lines, and even developed a special line of mice. In ordinary mice, Neu5Gc is synthesized from the basement in the cells, so E. coli easily uses this. As it turned out, if you artificially turn off – as scientists say, “knock out” the gene that allows you to synthesize Neu5Gc, then Shiga sticks have no effect on them.
The secret of the “Spanish woman”
Scientists have unraveled the secret of unprecedented mortality from the “Spanish flu”. Tens of millions of people died in 1918 due to two mutations that allowed a new strain of influenza to bind tightly to sugars … The use of host signaling molecules as a targeted attack target for microorganisms is not new.
Influenza viruses also bind to sugars on the surface of cells, HIV virions bind to the signaling CD4 molecules of the membrane of T-helper immune cells, and malarial plasmodium recognizes erythrocytes by the same neuraminic acid residues.
Scientists not only know these facts, they can outline all the stages of the resulting contact and subsequent penetration of an infectious agent, or its toxin, into a cell. But this knowledge, unfortunately, cannot lead to the creation of powerful drugs. The fact is that the same molecules are used by the cells of our body to communicate with each other, and any impact directed at them will inevitably affect not only the life of the pathogen, but also the work of our body.
The human body does without Neu5Gc, and in order to avoid contracting a dangerous food infection, it is enough to prevent this molecule from entering the body – that is, do not eat meat and milk. Of course, you can rely on ultra-thorough roasting of meat and sterilization of milk, but these products are easiest to avoid.
For the “Nobel” scale, this work was not enough except for the subsequent attempt to infect E. coli, because in this case, the authors of this study could compete in popularity with the discoverers of Helicobacter pylori, which causes stomach ulcers. In the early 1980s, to prove himself right to the conservative medical world, one of them deliberately infected himself with “ulcer agents.” And 20 years later he received the Nobel Prize.