Scientists reprogrammed the common bacterium E. coli so it requires a synthetic amino acid to live. BSIP/UIG via Getty Images hide caption Scientists reprogrammed the common bacterium E. coli so it requires a synthetic amino acid to live. Researchers at Harvard and Yale have used some extreme gene-manipulation tools to engineer safety features into designer organisms. This work goes far beyond traditional genetic engineering, which involves moving a gene from one organism to another. In this case, they're actually rewriting the language of genetics. The goal is to make modified organisms safer to use, and also to protect them against viruses that can wreak havoc on pharmaceutical production. To understand what they've done, you may need to remember a bit of basic biology. The enzymes and other proteins in our bodies are all built from building blocks called amino acids. There are usually just 20 amino acids in nature. But George Church, a professor of genetics at Harvard Medical School, has created a bacterium that requires an additional amino acid, one made in the lab and not found in nature. His lab did that by rewriting the bacteria's genetic language to add a "word" that calls for this unnatural amino … Continue reading →

Mediscan/Corbis Synthetic biologists hope to treat disease in the gut by making Lactobacillus bacteria (pictured) that are dependent on an artificial amino acid. Critics of genetic engineering have long worried about the risk of modified organisms escaping into the environment. A biological-containment strategy described this week in Nature1, 2 has the potential to put some of those fears to rest and to pave the way for greater use of engineered organisms in areas such as agriculture, medicine and environmental clean-up. Two US teams have produced genetically modified (GM) bacteria that depend on a protein building block an amino acid that does not occur in nature. The bacteria thrive in the laboratory, growing robustly as long as the unnatural amino acid is included in their diet. But several experiments involving 100billion or more cells and lasting up to 20days did not reveal a single microbe capable of surviving in the absence of the artificial supplement. Our strains, to the extent that we can test them, wont escape, says Dan Mandell, a synthetic biologist at Harvard Medical School in Boston, Massachusetts, and an author on one of the two studies describing the strategy. The microbes also do not swap their engineered DNA … Continue reading →