Saccharomyces cerevisiae may be the go-to microorganism for bakers and brewers of alcoholic beverages, but the yeast species also has a long and storied history in the world of scientific experimentation.

Now, a team of scientists has managed to establish what they call "in silico feedback control" between S. cerevisiae and a computer — granting the team precise control over the yeast's expression of specific genes.


According to the BBC, the computer uses flashes of light to turn gene expression on and off within the yeast, via a molecule known as phytochrome. When phytochrome is exposed to red light, it changes shape. Its new form allows it to turn on the yeast's genetic machinery required for producing a given protein. When phytocrome is exposed to an even deeper-red light, however, it changes shape again, letting its foot off the gas that drives gene expression of the protein.

But a yeast whose gene expression can be controlled with light is only unidirectional. To create a real-time feedback loop, the researchers had to equip the yeast with what's known as a "reporter" molecule. This reporter molecule not only recognizes when the yeast is expressing the gene of interest, it gives off light, too. This lets the computer know that the protein's gene is actually being turned on, allowing it to regulate its control of the yeast's gene expression based on reports from the field, so to speak.

"The neat thing about this is that there are many people who have tried to do things like this by, for example, coding in the cell itself a synthetic circuit, putting genes and mechanisms in the cell," said researcher John Lygeros, who led the study, published in this week's Nature Biotechnology.

"That's had limited success up to now."

So what's the upshot of all this? Imagine not only being able to tell a cell what to do, but being able to get feedback from the cell that lets you know exactly what it's going through; the power to control life is one thing, but the power to do so in an informed and specific manner? That's Borg control — we're talking totally game-changing stuff.


"It's quite difficult to engineer synthetic circuits that do something robustly in the cell, and the hope is that by augmenting this with external signals, you can get them to behave better," explains Lygeros.

"That for example may have applications in biofuel production, or antibiotic production, where they use genetically engineered organisms to increase the yields of reactions."

Nature via BBC
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