As the molds were tamed by people


Experts from the Vanderbilt University decided to find out how the ancient brewers were able to "domesticate" the fungus Aspergillus and get him to cooperate with the yeast, while not synthesize toxins.

What is common between a cow, a dog, a cat, for example, corn? It’s all domesticated organisms. With regard to animals and plants, scientists have long figured out which genetic changes have occurred in them after their domestication by man. But with micro-organisms is not so clear in their study of science has not advanced very far.

This is partly due to the fact that people do not even realize that wine, cheese, beer, sauerkraut create certain strains of fungi and bacteria, which have been the same way domestication like dogs and cows. Obviously, this process could not pass without leaving a trace, and any changes should be imprinted in the genome, but what were the changes that scientists still do not know it.

The study of this problem has been very few scientists and experts from Vanderbilt one of them. They studied the fungus Aspergillus oryzae, used in the production of soy sauce, sake and miso. Its closest relative Aspergillus flavus. Although their genomes differ only by 0.5%, the difference between these two types of enormous: A. oryzae is completely harmless, while A. flavus is a pathogen that infects crops and synthesizing deadly substance aflatoxin.

"Tame" this mushroom Far brewers. They noted that Aspergillus is not just spoil the taste of the final product toxins, but rather improved it. They isolated the mold and put it in the greenhouse conditions. Since you now have the fungus was in excess, protected from anyone it was not necessary, its metabolism is shifted to the conversion of starch into sugar. Aspergillus began to synthesize new enzymes that would help him most effectively cope with this task. In this case, the secondary metabolites that produce protection from competitors in a given situation became irrelevant.

Thus, in the absence of competition A. Oryzae lost its toxic properties. In contrast, plants and animals, which result in the domestication changed only growth parameters, the appearance and productivity, in the case of fungus occurred "metabolic domestication."

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