clock menu more-arrow no yes

Filed under:

Scientists create new method to tame artificial organisms: make them dependent on lab food

New, 14 comments

Future artificial organisms may come with better built-in brakes to prevent their spread, two papers published in the journal Nature suggest. That may make genetically modified organisms safer for use outside the lab.

Some people worry that GMOs might spread widely beyond their intended use, damaging the environment. Today, two groups of scientists announced they've created modified E. coli strains that requires lab-made food in order to survive — so if any of these altered E. coli make it to the wild, they're toast.

GMOs can evolve ways to shut down "kill switches"

Other kinds of containment exist for GMOs. One strategy is to disable their ability to make certain kinds of essential nutrients — but this strategy isn't foolproof, since it may be possible to scavenge that substance from the environment. And over several generations, organisms may evolve a new way to create the nutrient. Another way to contain GMOs is to create a "kill switch" — making bacteria vulnerable to a toxin. But again, the evolutionary process could provide a way for these creates to shut down their kill switches. Today's findings may provide a new path to contain any possible escapees, one that isn't vulnerable to evolutionary pressures.

"We’re standing at the cusp of the biotech century and the first thing we need to do is develop robust safety measures," said Farren Isaacs, a biologist at the Yale School of Medicine, and the lead researcher on one of the studies, in a telephone interview.

In the future, GMOS could be used to clean up oil spills and improve food production

Genetically-modified bacteria are already in use to produce drugs, high-value chemicals, and milk and dairy products, said George Church, a geneticist at Harvard Medical School, and the lead researcher on the other study, in a press conference. Concerns about how these human-modified bacteria might affect the environment has limited their use. Today's new safety stopgaps might allow for more widespread applications, like cleaning up oil spills and improving food production. Isaacs says that his and Church’s research "establishes a foundation to more broadly develop these types of technology in other organisms." Of course, that’s still years away.

Isaacs and Church led research published in 2013 that radically redesigned E. coli bacteria; the two are frequent collaborators, although their work on today's papers was separate. Now, Church and Isaacs have expanded upon this research in a pair of studies.

Genetically modified organisms could be used to further improve agricultural methods.

The new strains of E. coli are dependent on artificial food

Church and colleagues’ paper today updates their redesign, making the modified E. coli’s metabolism dependent on a lab-created amino acid in several places across the genome. Amino acids are the compounds that make up proteins, which perform a variety of essential tasks in living things. Without the artificial amino acid, the E. coli can't translate their RNA into functioning proteins. In order to acquire the amino acid, the bacteria require lab-prepared nutrients. The scientists used computational design to determine how to make the E. coli dependent on artificial amino acids. In so doing, they redesigned three proteins E. coli requires to live, and created two new E. coli strains dependent on artificial food.

Isaacs' group also used the 2013 strain of E. coli and engineered it to be dependent on an artificial amino acid. But Isaacs and his collaborators a different method: their target was essential genes. Their group made sure that the genes couldn’t code for proteins without the artificial amino acids — meaning, again, that the E. coli couldn’t function without its lab-made meal. "This means you can restrict the growth [of these organisms] to localized environments. It really solves a long-standing problem in biotechnology," Isaacs told The Verge.

Modifying plants in the same way is "more of a challenge, but not out of reach."

The increased safety isn't the only reason these bacteria are attractive. They're also more resistant to viral infections, Church said in the press conference. Though plant and animal cells haven't been modified in this way, that's a future direction for his research. Plants usually have about nine times as many protein-coding genes as E. coli — and those are the genes that matter for the technique, also introduce new time constraints as researchers were forced to wait longer for samples to grow and mature. "They are definitely more of a challenge, but not out of reach," Church said at the press conference.

However, some scientists are skeptical that Church and Isaacs’ methods could be so easily transplanted into complex organisms. The more genes an organism has, the greater the chances of unforeseen consequences, says Professor Alison Smith of the University of Cambridge’s Department of Plant Sciences. "The work that [Church and Isaacs] have done is very elegant, but the spin they’ve put on it that it will 'solve' GM — meaning GM plants and possible GM animals as well — is an overstatement," Smith says. The genetic system of higher organisms like plants and animals or even yeast is completely different to that in bacteria and I think [theirs] might be an extrapolation too far." Smith says that using GMOs in industrial fermenters, for example, may offer an incredibly controlled environment, but that the behavior of any organism in the wild is much harder to predict.

"Having important safety features such as recoding [or] the restriction of the viability of organisms to synthetic amino acids are going to be critical in trying to address these goals," says Isaacs. "In many ways we’re at the early stages from a biotechnology perspective… and endowing safeguards now is going to be important to allow the field to progress going forward."