摘要

细菌素是细菌分泌抑制竞争者生长的常见抗菌剂。它们的生产通常是有条件的，由底层法定人数感应调节电路管理。尽管受控细菌素合成的分子基础已经越来越多地被揭示，但其量化的生态学作用尚未得到很好的表征。在这里，我们提出了一个细菌素合成的综合模型，在两种物种竞赛中，其中一个物种与另一个物种对抗资源利用。在一个混合良好的环境中，我们发现细菌素的产生对物种竞争的结果有积极或消极的贡献，这取决于细菌素在调解竞争中的利益和由于代谢负荷导致的适应成本之间的权衡。折衷还决定了组成型细菌素生产和群体感应( QS )控制生产之间的相对优势。有趣的是，在自然发生的细菌素生产成本高的情况下，QS控制的合成优于组成型，这为本质上密度相关的细菌素生产的广泛流行提供了定量解释。此外，通过扩展我们的研究以包括竞争团体的空间动力学，我们表明，我们的发现，高成本制度下QS受控合成的优势，仍然适用于复杂环境。这项工作通过在人口增长期间揭示它的成本和收益，提供了我们对细菌素介导的社区组织以及微生物生态学的一般理解的生态学见解。

Bacteriocins are common antimicrobial agents that bacteria secrete to suppress the growth of competitors. Their production is often conditional, governed by underlying quorum sensing regulatory circuitry. Although the molecular underpinnings of controlled bacteriocin synthesis have been increasingly revealed, its quantitative ecological role has not been well characterized. Here, we present an integrated model of bacteriocin synthesis in the context of two-species contests where one species opposes the other for resource utilization. In a well-mixed environment, we find that bacteriocin production can contribute positively or negatively to the outcome of species competition, determined by the tradeoff between the benefit of bacteriocins in mediating competition and the fitness cost due to metabolic load. The tradeoff also determines the relative advantage between constitutive bacteriocin production and quorum sensing (QS) controlled production. Interestingly, under the naturally occurring scenario where bacteriocin production has a high cost, QS controlled synthesis outperforms constitutive, which offers a quantitative interpretation for the wide prevalence of density-related bacteriocin production in nature. Furthermore, by extending our study to include spatial dynamics of competing communities, we show that our finding, the superiority of QS controlled synthesis in the high cost regime, remains valid for complex settings. This work provides ecological insights into bacteriocin synthesis by revealing its cost and benefit during population growth, advancing our fundamental understanding of bacteriocin-mediated community organization as well as microbial ecology in general.

https://link.springer.com/article/10.1007/s12195-016-0447-6