Caterpillar cottonseed scoop has developed an unusual strategy to protect against pests and diseases, tame bacteria that produce antibiotics in the gut in exchange for nutrients.
“We have long suspected that microbes in the gut are a key component of insect protection from infections, but to date the mechanism of this protection remained unknown to us. We have shown that the evolutionary success of insects is at least partly due to their symbiotic relationship with bacteria with which they evolved millions of years,” said Yun-Tzu Shao (Yongqi Shao) from Zhejiang University (China).
Virtually all the antibiotics that exist and are used today, were invented by nature, by bacteria or fungi to protect themselves from other microbes and to clear the living space from the competition. People opened them only in the first third of the 20th century, and today antibiotics are the basis of health and loss of their efficiency is a growing concern for physicians.
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Shao and his colleagues found that antibiotics regularly use other living things – caterpillar cottonseed scoop (Spodoptera littoralis), thunderstorms of agriculture of India, Egypt and many other southern agricultural countries.
Team Shao long enough studying bacteria living in the intestines of these insects, trying to understand how they affect their lives and what role these microbes play in digestion and in protecting the body from infections. Watching the growth of caterpillars Spodoptera littoralis, scientists noticed a curious thing – a variety of types of bacteria in their gut did not grow, and decreased.
For example, after hatching from eggs in the intestine scoop was attended by several dozen species of clostridia and enterococci bacteria involved in the digestion process, however, towards the pupation of their microflora almost half consisted of one species of enterococci — Enterococcus mundtii. If these bacteria remove from the intestine of caterpillars, they die quickly in the stage of pupation, literally rotting alive. This discovery surprised scientists, because this kind of germs have always been considered harmless and neutral with respect to other bacteria.
In order to reveal their essence, biologists have grown a few colonies of Enterococcus mundtii and put them in culture, where grew several other species of enterococci. Watching them, biologists realized that under certain conditions, these harmless microbes begin to release into the environment of large quantities of previously unknown science of the antibiotic from the class of bacteriocins. The scientists called it monticino after the Latin name of these microbes.
Antibiotic contributes to the development of symbiosis by providing the advantages and bacteria, which can grow almost indefinitely in the gut of the insect, and by the caterpillars, which these microbes protect against pathogens. We think that the same relations exist between other types of bacteria and insects — adds Wilhelm Boland (Wilhelm Boland) from the Institute of chemical ecology in Jena (Germany).
According to Shao, bacteriocins microflora can help mankind to find the key to solving the problem with the growing immunity of microbes to antibiotics used today for two reasons. They only work on a very narrow set of bacteria, which limits the possibility of adapting other microbes to them. In addition, the insects I use them for hundreds of millions of years, suggests that resistance to such substances produced by bacteria very slowly.