Space, Time, and Host Evolution Facilitate Coexistence of Competing Bacteriophages: Theory and Experiment
Space, Time, and Host Evolution Facilitate Coexistence of Competing Bacteriophages: Theory and Experiment
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DOI：
10.1086/597226
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发表时间：
2009-04-01
影响因子：
2.9
通讯作者：
Krone, Stephen M.
中科院分区：
文献类型：
--
作者：
Coberly, L. Caitlin;Wei, Wei;Krone, Stephen M.
我们对空间结构和时间在两种病原体争夺单一宿主中的作用进行了实验/理论联合研究。我们提出了一种自然机制，当宿主进化和竞争动态发生在相似的时间尺度上时，竞争病原体可以共存。我们的实验系统包括一个单一的细菌宿主物种和两个竞争的噬菌体菌株生长在琼脂板上，在每个孵育周期后将噬菌体群体的样品连续转移到新鲜的宿主群体中。实验包括两个孵育时间和两种转移方案，在每次转移时维持或破坏病毒的空间结构。在两种转移方案下，同一噬菌体作为主要竞争者。两种处理之间的一个显著区别是，弱竞争者能够在长孵育实验中坚持下来，但在短孵育实验中却不能。数学和实验证据表明，共存是由于抗性突变宿主细胞的出现，为较弱的竞争对手提供了短暂的“时空避难所”。我们的数学模型是基于个体的，捕捉到单个细胞水平的随机空间动力学，并有助于解释在各种实验条件下的行为差异。
We present a joint experimental/theoretical investigation into the roles of spatial structure and time in the competition between two pathogens for a single host. We suggest a natural mechanism by which competing pathogens can coexist when host evolution and competitive dynamics occur on similar timescales. Our experimental system consisted of a single bacterial host species and two competing bacteriophage strains grown on agar plates, with a serial transfer of samples of the bacteriophage population to fresh host populations after each incubation cycle. The experiments included two incubation times and two transfer protocols that either maintained or disrupted the spatial structure of the viruses at each transfer. The same bacteriophage acted as the dominant competitor under both transfer protocols. A striking difference between the treatments is that the weak competitor was able to persist in the long-incubation experiments but not in the short-incubation experiments. Mathematical and experimental evidence suggest that coexistence is due to the appearance of resistant mutant host cells that provide a transient "spatiotemporal refuge" for the weaker competitor. Our mathematical model is individual based, captures the stochastic spatial dynamics down to the level of individual cells, and helps to explain the differences in behavior under the various experimental conditions.