西亚试剂：Counteraction of antibiotic production and degradation stab

A major challenge in theoretical ecology is understanding how natural microbial communities support species diversity, and in particular how antibiotic-producing, -sensitive and -resistant species coexist. While cyclic ‘rock–paper–scissors’ interactions can stabilize communities in spatial environments, coexistence in unstructured environments remains unexplained. Here, using simulations and analytical models, we show that the opposing actions of antibiotic production and degradation enable coexistence even in well-mixed environments. Coexistence depends on three-way interactions in which an antibiotic-degrading species attenuates the inhibitory interactions between two other species. These interactions enable coexistence that is robust to substantial differences in inherent species growth rates and to invasion by ‘cheating’ species that cease to produce or degrade antibiotics. At least two antibiotics are required for stability, with greater numbers of antibiotics enabling more complex communities and diverse dynamic behaviours ranging from stable fixed points to limit cycles and chaos. Together, these results show how multi-species antibiotic interactions can generate ecological stability in both spatially structured and mixed microbial communities, suggesting strategies for engineering synthetic ecosystems and highlighting the importance of toxin production and degradation for microbial biodiversity.

了解多物种群落的稳定性在面对通过抗生素生产所发生的负相互作用时是怎样维持的，是微生物生态学中的一个关键目标。大多数关于抗生素相互作用的生态模型都假设物种之间是配对关系，这种关系导致“石头剪刀布”式的循环和空间分离。但这种情况并未在现场观测中反映出来(观测中群落之间的相互混合情况要复杂得多)。相反，Eric Kelsic及同事提出了一个三物种相互作用分析方案，在其中一个物种能够降解抗生素。通过将模型模拟和实验确认相结合，本文作者显示，将能够降解抗生素的物种包括在内，可以让系统可靠地向一个相互混合的稳定状态发展。