外刊阅读20241226｜“镜像生物”可能造成无法挽回的灾难！

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Handedness, more formally known as chirality , is hugely important in biology because interactions between biomolecules rely on them having the expected form. For example, if a protein’s handedness is reversed, it cannot interact with partner molecules, such as receptors on cells. “Think of it like hands in gloves,” says Katarzyna Adamala, a synthetic biologist at the University of Minnesota and a co-author of the article and the accompanying technical report, which is almost 300 pages long. “My left glove won’t fit my right hand.”

The authors are worried about mirror bacteria, the simplest life-form their concerns apply to. The capability to create mirror bacteria does not yet exist and is “at least a decade away,” they write, but progress is underway. Researchers can already synthesize mirror biomolecules, such as DNA and proteins. At the same time, progress has been made toward creating synthetic cells from nonmirrored components .

Many immune system mechanisms also rely on handedness. T cells, responsible for recognizing foreign invaders, for example, might fail to bind to something with the wrong handedness. So these therapies could also avoid triggering immune reactions in patients. “A mirror peptide will not be readily degraded, which is why they could be great as therapeutics,” says co-author John Glass, a synthetic biologist at JCVI. “We see absolutely no reason to prohibit this.”

A potential application of mirror bacteria is might be bioreactors, biological factories that use cells or microorganisms to manufacture various compounds, such as antibiotics and other pharmaceuticals . Bacteriophages (viruses that infect bacteria) can wipe out bacteria-based bioreactors, costing huge amounts of time and money, but it is likely they wouldn’t infect mirror bacteria, because they wouldn’t recognize their molecules. Similarly, natural predators, like amoebae, which consume normal bacteria, would fail to recognize mirror bacteria as food.

It is these supposedly advantageous properties that gave rise to the scientists’ concerns. “All the practical applications that drew us into this field are the reasons we’re terrified of it now,” Adamala says. The ability to evade immune responses could allow bacteria to cause lethal infections as they multiply unchecked. Unlike viruses, bacteria don’t need to interact with specific molecules to infect an organism, and mirror bacteria could infect a broad range of hosts, including humans, other animals, and plants. And a lack of predators could enable mirror bacteria to spread widely through ecosystems.