Scientists modify a yeast cell and turn it into a cannabis tracker

Researchers at the University of Copenhagen’s Faculty of Science have engineered a yeast cell to detect active substances in cannabis and turn it red when it does. The result paves the way for more players to discover new drug substances and for a new type of drug test that can be performed with a smartphone.

Yeast cells are simple organisms. They do two things in life: eat and propagate. Now researchers from the Department of Plant and Environmental Sciences at the University of Copenhagen have given common baker’s yeast cells a new function.

The researchers replaced the yeast cell’s libido with a sense of taste and smell that allows it to detect cannabinoids, the active substances in cannabis. Going one step further, the researchers made the yeast turn red or glow when it successfully detects cannabinoids. The study was published in Nature Communication.

“We have created a living sensor from the yeast cell, which can now detect cannabinoids or molecules that have the same function as cannabinoids, even though they look very different from cannabinoids. Among other things, the biosensor can be used to search for new substances with the same properties as cannabinoids. This could democratize medicinal development so that pharmaceutical companies are not the only ones equipped to discover new substances”, explains Professor Sotirios Kampranis of the Department of Plant and Environmental Sciences, who led the research.

Turns red when detecting cannabinoids

Humans use hundreds of different GPCRs (G protein-coupled receptors) to taste and smell. In our noses alone, 400 different GPCRs allow us to detect and distinguish the smell of roses and freshly baked bread, each of which activates different GPCRs which then signal the brain.

Together with his research colleagues, Professor Kampranis swapped the GPCR that yeast cells use to detect the opposite sex in an environment, with the GPCR that we humans use to recognize cannabinoids. At the same time, the researchers supplemented the yeast cell’s genetic material with a set of new genes that cause it to turn red or even glow when it detects nearby cannabinoids.

“The yeast cell now gives off a signal when there are cannabinoids in the environment of the yeast cell. This allows us to screen thousands of plants for substances with therapeutic potential. And we can also determine whether people are using drugs or if someone tries to smuggle cannabinoids or ‘designer drugs’ through an airport checkpoint,” says Professor Sotirios Kampranis.

Discovery of four new substances in one day

Cannabinoids are known to be linked to sleep, appetite, and pain relief. In fact, we naturally have them in our body where they are called endocannabinoids. This is precisely why the researchers chose to encode the ability to find cannabinoids in yeast cells. But in principle, they could have done this for opioids or any other group of medicinal substances. This is precisely why the researchers chose to encode the ability to find cannabinoids in yeast cells. But in principle, they could have done that for opioids or any other drug group.

There is no doubt that the yeast cell can find new substances. In the first tests, the researchers used the yeast cell to study 1600 random substances from an extensive library of chemical compounds available at the University of Copenhagen. It didn’t take long to get a bite.

“In just one day, the yeast cell found four undiscovered substances that had never been associated with anti-inflammatory or pain-relieving properties, but could potentially be used for these purposes,” says Sotirios. Kampranis.

When pharmaceutical companies research new drugs today, it is with the help of state-of-the-art robotic and laboratory equipment that universities and other non-commercial entities will never be able to afford. The fact that researchers have developed an alternative could allow more people to search for useful substances in nature.

“It’s a crowdsourcing approach whereby smaller labs can find more potential new substances for pharmaceutical use. I don’t see it as competition with pharmaceutical companies, but as something that can create synergy between independent players of the scientific world and the pharmaceutical industry,” says Professor Kampranis.

Smartphone accessory can find drugs

The researchers also developed a portable plastic device containing a yeast cell biosensor. Plant material, saliva, urine, blood, material from a suitcase, or whatever one wishes the yeast cell to test, is placed in the gadget.

The device then uses the smartphone’s camera to see if the yeast cells light up, delivering its result in just 15 minutes. The app might be able to help police and others track down drugs at airports or administer drug tests.

“We can test both natural cannabinoids and synthetic drugs – chemicals that have very different structures – with the same effects as cannabinoids. In principle, we could also adapt the yeast cell to be able to detect opioids such as morphine, fentanyl and oxycodone,” says Sotirios Kampranis.

The device can be 3D printed or assembled using materials easily obtained online. Researchers are now working to make the test tool available for free, to as many people as possible, but at the same time be able to retain control for maintenance and further development.


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