Yet another expensive techno-fix for problem created by GMO industry
 
Two papers have been published (items 2 and 3 below) reporting scientists’ use of synthetic amino acids that allow them to create "genetic firewalls" that could prevent specially designed GMO crops or animals from escaping into the wild and causing environmental damage.

Despite the hype surrounding this announcement, systems of containment for GMOs by making them dependent on synthetic nutrients are not new. A bacterial strain used in recombinant DNA studies back in the 1970s was designed to be dependent on a synthetic nutrient that does not occur in the wild. It was specifically used to prevent proliferation of the recombinant E. coli outside the laboratory.

Of course, such “genetic firewalls” are yet another expensive techno-fix to a problem that the GMO industry created in the first place. We look forward to the day when research funders wake up to the fact that coming up with endless techno-fixes to solve the problems caused by a previous technology is unsustainable and a waste of resources.

The potential toxicity and non-target impacts of the synthetic amino acid will need to be separately addressed, in addition to the initial assessment of the impacts of the GMO it is meant to contain. And more research needs to be done on the effectiveness of such containment methods.

1. Creating a “genetic firewall” for GMOs
2. Bio-containment of genetically modified organisms by synthetic protein design
3. Recoded organisms engineered to depend on synthetic amino acids
—

1. Creating a “genetic firewall” for GMOs

LA Times, 21 Jan 2015
http://www.latimes.com/science/sciencenow/la-sci-sn-gmo-escape-20150121-story.html

Synthetic amino acids may one day allow scientists to create "genetic firewalls" that prevent GMO crops or animals from escaping into the wild and causing environmental damage, according to Harvard and Yale researchers.

On Wednesday, scientists announced that they had genetically engineered bacteria whose very survival depended on lab-formulated amino acids. By "locking in" this synthetic nutritional requirement, researchers said the bacteria would quickly die if they escaped their carefully controlled environment and entered the world at large.

"I don't want to be alarmist or anything, but I think the point is that these organisms do spread," said George Church, a Harvard Medical School genetics professor.

The altered bacteria, which Church and his colleagues dubbed genomically recoded organisms, or GROs, were described in a pair of studies published Wednesday in the journal Nature.

Genetically altered bacteria are used to produce a growing number of products, including pharmaceutical proteins such as insulin, dairy items such as yogurt, and polymers used to create textiles.

While it is much easier to alter the genetic coding of bacteria than it is to alter plant and animal genomes, Church said that it was plausible that the technique could be extend to more complicated GMOs, such as crops.

Church and Farren Isaacs - an assistant professor of molecular, cellular and developmental biology at Yale, and the senior author of one of the studies - said their work was motivated by the concern that modified organisms could enter the wild and out-compete natural species. It is this concern that has caused some to heavily criticize the use of GMOs in industry and agriculture.

"It's a scenario," Church told reporters. "You want to get ahead of these things, rather than wait until you have a problem."

The key to designing a fail-safe measure involves amino acids, which bacteria and other organisms use to assemble the multitude of proteins necessary for life functions.

In the natural environment there are only 20 such amino acids, yet cells use this limited palette of chemicals to produce a dizzying array of specialized proteins. The recipe for each of these proteins is encoded in an organism's genome.

In the Harvard study, Church and his colleagues altered the genome of E. coli bacteria so that it contained new instructions for a single, critical protein, but required the man-made amino acid, biphenylalanine, or bipA, to produce it.

"We do consider this a new class of organism," Church told reporters. "It's not just a new species. In a way it's a new kingdom."

It is possible that after reproducing for generations, the altered microbe will eventually develop a mutation that allows it to survive without bipA, Church said.

To guard against this, researchers said they would need to alter the bacteria so that it created a number of essential proteins using synthetic amino acids.

Church and Isaacs said they hoped to make such bacteria attractive to industry by also making the microbes immune to viruses.

"Our next step is to make a truly multi-virus-resistant organism that's resistant to all viruses, even viruses we haven't characterized yet from the wild," Church said.

2. Bio-containment of genetically modified organisms by synthetic protein design

Daniel J. Mandell, Marc J. Lajoie, Michael T. Mee, Ryo Takeuchi, Gleb Kuznetsov, Julie E. Norville, Christopher J. Gregg,    Barry L. Stoddard, & George M. Church
Nature (2015), Published online 21 January 2015
doi:10.1038/nature14121
http://www.nature.com/nature/journal/vaop/ncurrent/full/nature14121.html

Abstract
Genetically modified organisms (GMOs) are increasingly deployed at large scales and in open environments. Genetic bio-containment strategies are needed to prevent unintended proliferation of GMOs in natural ecosystems. Existing bio-containment methods are insufficient because they impose evolutionary pressure on the organism to eject the safeguard by spontaneous mutagenesis or horizontal gene transfer, or because they can be circumvented by environmentally available compounds. Here we computationally redesign essential enzymes in the first organism possessing an altered genetic code (Escherichia coli strain C321.ΔA) to confer metabolic dependence on non-standard amino acids for survival. The resulting GMOs cannot metabolically bypass their bio-containment mechanisms using known environmental compounds, and they exhibit unprecedented resistance to evolutionary escape through mutagenesis and horizontal gene transfer. This work provides a foundation for safer GMOs that are isolated from natural ecosystems by a reliance on synthetic metabolites.

3. Recoded organisms engineered to depend on synthetic amino acids

Alexis J. Rovner, Adrian D. Haimovich, Spencer R. Katz, Zhe Li, Michael W. Grome, Brandon M. Gassaway, Miriam Amiram, Jaymin R. Patel, Ryan R. Gallagher, Jesse Rinehart, Farren J. Isaacs
Nature (2015), published online 21 Jan 2015
doi:10.1038/nature14095
http://www.nature.com/nature/journal/vaop/ncurrent/full/nature14095.html

[from the introduction]
Genetically modified organisms (GMOs) are increasingly used in research and industrial systems to produce high-value pharmaceuticals, fuels and chemicals. Genetic isolation and intrinsic bio-containment would provide essential biosafety measures to secure these closed systems and enable safe applications of GMOs in open systems, which include bio-remediation and probiotics. Although safeguards have been designed to control cell growth by essential gene regulation, inducible toxin switches and engineered auxotrophies, these approaches are compromised by cross-feeding of essential metabolites, leaked expression of essential genes, or genetic mutations. Here we describe the construction of a series of genomically recoded organisms (GROs) whose growth is restricted by the expression of multiple essential genes that depend on exogenously supplied synthetic amino acids (sAAs).