News in Science

Discovery sparks 'home-brew drugs' concern

Baking bad Scientists have unlocked a pathway for producing opiates from genetically-engineered yeast, but fear the discovery could one day be a bonanza for criminals.

The team of US and Canadian scientists are calling on lawmakers to regulate the area of research to avoid abuse.

Other experts agree, saying anyone with basic skills could use such a yeast to churn out morphine, codeine and drugs using a simple home-brew beer kit.

The discovery, published in the scientific journal Nature Chemical Biology, comes on the heels of a study published last month in the journal PLOS ONE.

Together, the papers describe the 15 key steps towards bio-engineering yeast that would feed on sugar and exude opiates and other therapeutic drugs.

For centuries, morphine and other opioids have been the go-to drugs for pain relief. But their molecular structure is so complex, they are isolated or manufactured from compounds in plants because they can not be chemically synthesised on a commercial scale.

The goal of the research is to provide cheaper and possibly less addictive painkillers from a more dependable source than the poppy.

The team of synthetic biologists inserted an enzyme gene from beets to coax yeast into converting tyrosine -- an amino acid easily derived from sugar -- into a compound called reticuline.

Reticuline is a molecular "hub", meaning it is the springboard for making morphine, codeine and oxycodone, as well as anti-spasmodic drugs like papaverine.

The team did not go on to make these drugs, but the process of going from reticuline to codeine and morphine in yeast is already known. What had been missing in the knowledge chain was getting from tyrosine to reticuline.

The discovery may be a boon in pharmaceutics, but it also "dramatically speeds up the clock for when home-brewing drugs could become a reality," the researchers caution.

"We're likely looking at a timeline of a couple of years, not a decade or more, when sugar-fed yeast could reliably produce a controlled substance," says the study's co-author John Dueber of the University of California, Berkeley.

"The time is now to think about policies to address this area of research. The field is moving surprisingly fast, and we need to be out in front so that we can mitigate the potential for abuse."

Make-your-own morphine?

In a blunt commentary in Nature, a group of leading academics called for regulation of 'home brew' opiates, saying the way was now open for engineering a yeast strain that would do the whole drug-making trick.

That, in turn, offered golden opportunities for criminals if this strain fell into the wrong hands.

"In principle, anyone with access to the yeast strain and basic skills in fermentation would be able to grow morphine-producing yeast using a home-brew kit for beer-making," says the group headed by Kenneth Oye, a political scientist at the Massachusetts Institute of Technology (MIT).

"If the modified yeast strain produced 10 grams of morphine, users would need to drink only one to two millilitres of the liquid to obtain a standard prescribed dose."

In addition to tighter lab security and tougher laws, the trio called for yeast strains to be engineered to produce drugs with limited street value, such as the painkiller thebaine.

Strains could also be engineered so that the yeast requires unusual food or laboratory conditions to thrive, thus raising the technological bar for gangs.

But another commentator wondered if the genie was not already out of the bottle.

"One would not have to obtain the safeguarded strain." says Christopher Voight Massachusetts Institute of Technology, who was not involved in the research.

"The information in this paper, combined with DNA synthesis, could be readily applied to rebuild the strain without ever gaining access to the physical DNA or strain from the authors," Voight says.

"It is going to be possible to 'home-brew' opiates in the near future."

The process described in the study is inefficient, requiring 300 litres of genetically engineered yeast to produce a single 30 milligram dose of morphine.

But with improvements that are well within reach, that dose could be obtained from "a glass of yeast culture grown with sugar on a windowsill," says Voight.