20 January 2017

An electric switch of gene activity has been created

Anna Manshina, N+1

American biotechnologists have learned to control the activity of bacterial genes using electricity. The bacterial switch obtained with the help of the new technology can be embedded in biosensors, medical devices and various gadgets. An article about the development was published in the journal Nature Communications (Tschirhart et al., Electronic control of gene expression and cell behavior in Escherichia coli through redox signaling).

Bacteria are widely used in molecular biology, biochemistry and genetic engineering. The most studied Escherichia coli bacteria to date can synthesize a wide range of biomolecules using gene modifications. Thanks to modified E.coli, an insulin analogue and some enzymes are produced in industrial volumes.

In addition to industrial applications, the ability of E.coli to synthesize the molecules necessary for humans could be useful in compact systems operating "on the spot", for example, directly in the human body. But for such systems to work perfectly, a switch is needed that would control the production of molecules.

Such a switch, powered by an electrical signal, was developed by the authors of a new study. They relied on E.coli's natural ability to respond to oxidative stress: a situation in which excessive oxidation of bacterial molecules threatens its life. In E.coli, the sensitive protein SoxR, when oxidized, interacts with a section of DNA that triggers the synthesis of proteins that regulate the respiratory activity of the bacterium and helps it cope with oxidative stress.

Scientists have used this natural sensitivity system to control the expression of any desired genes. After the introduction of suitable control elements into the genome, the modified bacteria, in response to oxidative stress, began to synthesize not only "antioxidant" proteins, but also those that were introduced by scientists. Oxidative stress was created using a simple electrode inserted into the nutrient medium: when a positive charge was applied to the electrode, the electron carriers oxidized the SoxR protein and triggered the mechanism of stress control and gene expression of additional proteins. When the electrode was switched off, expression stopped.

Thus, the researchers have developed an "electrogenetic switch" – a device that can regulate gene expression using an electrical signal. By embedding different genes encoding the necessary proteins, scientists have ensured that E.coli fluoresced and moved according to the signal.

Scientists believe that due to its simplicity and variability, this design can find application in the medical field and in the field of biotechnology within a couple of years. The device can be integrated, for example, into autonomous and semi-autonomous systems suitable for the diagnosis and therapy of diseases: if pathogenic bacteria are detected, such a system will be able to quickly produce an antibiotic and immediately inject it into the patient's blood.

Bacteria are used not only in the production of biomolecules, the food industry and medicine. They are used even in construction, for example, in the production of cement.

Portal "Eternal youth" http://vechnayamolodost.ru  20.01.2017

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