Szilágyi András, Boza Gergely, Scheuring István
MTA-ELTE, Theoretical Biology and Evolutionary Ecology Research Group Department of Plant Systematics, Ecology and Theoretical Biology, Pázmány Péter sétány 1/c, Budapest, 1117, Hungary; MTA Centre for Ecological Research, Evolutionary Systems Research Group, Klebelsberg K. u. 3, Tihany, 8237, Hungary; Conflict and Cooperation in Evolutionary Systems Program, Institute of Advanced Studies Kőszeg, Chernel utca 14, Kőszeg, 9730, Hungary.
Department of Plant Systematics, Ecology and Theoretical Biology, Eötvös University, Pázmány Péter sétány 1/c, Budapest, 1117, Hungary; International Institute for Applied Systems Analysis (IIASA), Evolution and Ecology Program and Risk and Resilience Program, Schlossplatz 1, Laxenburg, A-2361, Austria.
J Theor Biol. 2017 Jun 21;423:53-62. doi: 10.1016/j.jtbi.2017.04.025. Epub 2017 Apr 27.
Antibiotic resistance carried out by antibiotic degradation has been suggested recently as a new mechanism to maintain coexistence of microbial species competing on a single limiting resource, even in well-mixed homogeneous environments. Species diversity and community stability, however, critically depend on resistance against social cheaters, mutants that do not invest in production, but still enjoy the benefits provided by others. Here we investigate how different mutant cheaters affect the stability of antibiotic producing and degrading microbial communities. We consider two cheater types, production and degradation cheaters. We generalize the mixed inhibition-zone and chemostat models introduced previously [Kelsic, E. D., Zhao, J., Vetsigian, K., Kishony, R., 2015. Counteraction of an tibiotic production and degradation stabilizes microbial communities. Nature521, 516-519.] to study the population dynamics of microbial communities in well-mixed environment, and analyze the invasion of different cheaters in these models. We show that production cheaters, mutants that cease producing antibiotics, always destroy coexistence whenever there is a cost of producing these antibiotics. Degradation cheaters, mutants that loose their function of producing extracellular antibiotic degrading molecules, induce community collapse only if the cost of producing the degradation factors is above a critical level. Our analytical studies, supported by numerical simulations, highlight the sensitivity of antibiotic producing and degrading communities to loss-of-function mutants.
最近有人提出，通过抗生素降解产生的抗生素抗性是维持在单一有限资源上竞争的微生物物种共存的一种新机制，即使在充分混合的均匀环境中也是如此。然而，物种多样性和群落稳定性关键取决于对社会作弊者的抗性，这些突变体不投入生产，但仍能享受其他个体提供的益处。在这里，我们研究不同的突变作弊者如何影响抗生素产生和降解微生物群落的稳定性。我们考虑两种作弊者类型，即生产作弊者和降解作弊者。我们推广了之前引入的混合抑制区和恒化器模型[凯尔西奇，E.D.，赵，J.，韦齐吉安，K.，基肖尼，R.，2015年。抗生素生产和降解的对抗作用稳定了微生物群落。《自然》521，516 - 519]，以研究充分混合环境中微生物群落的种群动态，并分析这些模型中不同作弊者的入侵情况。我们表明，生产作弊者，即停止产生抗生素的突变体，只要产生这些抗生素存在成本，就总会破坏共存状态。降解作弊者，即失去产生细胞外抗生素降解分子功能的突变体，只有在产生降解因子的成本高于临界水平时才会导致群落崩溃。我们的分析研究得到了数值模拟的支持，突出了抗生素产生和降解群落对功能丧失突变体的敏感性。
