Biocontainment is an essential feature when deploying genetically modified organisms (GMOs) in open system applications, as variants escaping their intended operating environments could negatively impact ecosystems and human health. To avoid breaches resulting from metabolic cross-feeding, horizontal gene transfer, and/or genetic mutations, synthetic auxotrophs have been engineered to become dependent on exogenously supplied xenobiotics, such as noncanonical amino acids (ncAAs). The incorporation of these abiological building blocks into essential proteins constitutes a first step toward constructing xenobiological barriers between GMOs and their environments. To transition synthetic auxotrophs further away from familiar biology, we demonstrate how bacterial growth can be confined by transition-metal complexes that catalyze the formation of an essential ncAA through new-to-nature reactions. Specifically, using a homogeneous ruthenium complex enabled us to localize bacterial growth on solid media, while heterogeneous palladium nanoparticles could be recycled and deployed up to five consecutive times to ensure the survival of synthetic auxotrophs in liquid cultures.

中文翻译：

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使大肠杆菌沉迷于新自然反应

在开放系统应用中部署转基因生物（GMO）时，生物遏制是一项必不可少的功能，因为逃避其预期操作环境的变体可能会对生态系统和人类健康产生负面影响。为避免代谢交叉喂食，水平基因转移和/或基因突变引起的破坏，已设计合成营养缺陷型生物，使其依赖于外源提供的异源生物，例如非规范氨基酸（ncAAs）。将这些非生物构建基团整合到必需蛋白质中，构成了在转基因生物及其环境之间构建异种生物屏障的第一步。为了使合成营养缺陷者远离熟悉的生物学，我们证明了如何通过过渡金属复合物限制细菌的生长，过渡金属复合物通过新自然反应催化必需的ncAA的形成。具体而言，使用均匀的钌络合物使我们能够将细菌生长定位在固体培养基上，而异质钯纳米颗粒可以回收利用并连续使用多达五次，以确保合成营养缺陷型在液体培养物中的存活。