Microbial population dynamics and evolutionary outcomes under extreme energy limitation
Microbial population dynamics and evolutionary outcomes under extreme energy limitation
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DOI：
10.1101/2021.01.25.428163
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发表时间：
2021-01
影响因子：
11.1
通讯作者：
W. Shoemaker;Stuart E. Jones;M. Muscarella;Megan G. Behringer;B. Lehmkuhl;J. Lennon
中科院分区：
文献类型：
--
作者：
W. Shoemaker;Stuart E. Jones;M. Muscarella;Megan G. Behringer;B. Lehmkuhl;J. Lennon
能量限制是一种普遍存在的现象，它支配着从单个细胞的新陈代谢到生物圈功能的微生物过程。通过跟踪不同细菌类群在长期饥饿下的种群动态，我们确定了维持生命的共同策略。虽然细菌有能力在几分钟到几小时的时间尺度上繁殖，但我们预测细菌种群可以持续数百到数千年，这为微生物的寿命设定了上限。虽然在我们的长期实验中观察到的动态是由死亡率的降低驱动的，但神秘的出生事件产生了推动进化的突变。我们的研究结果揭示了细胞寿命，并对主导地球广袤地区的极端环境中的生物多样性产生了影响。微生物通常栖息在能量有限的生态系统中，其中细胞的维持和繁殖受到高度限制。为了深入了解个体如何在这种条件下坚持，我们从21个异养细菌分类群的集合中获得人口统计学参数，在一个有效的封闭系统中对100个种群进行了1,000 d的普查。除了一个分类群生存长期资源稀缺，估计时间灭绝范围超过四个数量级，从100到105年。我们的发现证实了从古代环境样本中回收的长寿细菌的报道，同时提供了对持久性机制的深入了解。随着死亡率随着时间的推移而下降，通过清除死细胞来延长寿命。虽然在缺乏外源资源的情况下，繁殖受到抑制，但种群继续进化。获得了数百个突变，有助于纯化选择的全基因组特征以及适应的分子信号。一致的生态和进化动力学表明，远亲细菌以类似和可预测的方式对能量限制作出反应，这可能有助于微生物生命的稳定性和鲁棒性。
Significance Energy limitation is a widespread phenomenon that governs microbial processes ranging from the metabolism of individual cells to the functioning of the biosphere. By tracking the population dynamics of diverse bacterial taxa under prolonged starvation, we identified common strategies that sustain life. Although bacteria have the capacity to reproduce on timescales of minutes to hours, we predict that populations can persist for hundreds to thousands of years, placing upper bounds on microbial lifespans. While the dynamics observed in our long-term experiment were driven by a reduction in death rates, cryptic birth events generated mutations that fueled evolution. Our findings shed light on cellular longevity with implications for biodiversity in extreme environments that dominate vast expanses of Earth. Microorganisms commonly inhabit energy-limited ecosystems where cellular maintenance and reproduction is highly constrained. To gain insight into how individuals persist under such conditions, we derived demographic parameters from a collection of 21 heterotrophic bacterial taxa by censusing 100 populations in an effectively closed system for 1,000 d. All but one taxon survived prolonged resource scarcity, yielding estimated times to extinction ranging over four orders of magnitude from 100 to 105 y. Our findings corroborate reports of long-lived bacteria recovered from ancient environmental samples, while providing insight into mechanisms of persistence. As death rates declined over time, lifespan was extended through the scavenging of dead cells. Although reproduction was suppressed in the absence of exogenous resources, populations continued to evolve. Hundreds of mutations were acquired, contributing to genome-wide signatures of purifying selection as well as molecular signals of adaptation. Consistent ecological and evolutionary dynamics indicate that distantly related bacteria respond to energy limitation in a similar and predictable manner, which likely contributes to the stability and robustness of microbial life.