Predation Strategies of the Bacterium Bdellovibrio bacteriovorus Result in Overexploitation and Bottlenecks.
Predation Strategies of the Bacterium Bdellovibrio bacteriovorus Result in Overexploitation and Bottlenecks.
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噬菌蛭弧菌的捕食策略导致过度开发和瓶颈。
DOI：
10.1128/aem.01082-21
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发表时间：
2022
影响因子：
4.4
通讯作者：
Summers JK
中科院分区：
文献类型：
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作者：
Summers JK
随着抗菌药物耐药性的增加，迫切需要治疗感染或去除耐药细菌的替代方案，例如细菌捕食者噬菌蛭弧菌或噬菌体。因此，我们需要更好地了解微生物捕食者-被捕食者的动态。我们开发了恒化器捕食的大规模行动数学模型，该模型捕获了捕食者预期应用领域（例如废水处理、水产养殖或肠道）的典型低底物浓度和缓慢生长。我们的模型预测捕食者的生存需要最小的猎物细胞大小，这解释了为什么蛭弧菌比猎物小得多。被认为“太好”（攻击率太高、死亡率太低）的捕食者过度捕捞猎物，导致灭绝（公地悲剧）。令人惊讶的是，需要更长时间才能产生更多后代的捕食者在竞争中击败了更快地产生更少后代的捕食者（速率与产量的权衡）。捕食仅在最佳参数周围的狭窄区域内有效。此外，各种条件下的极端振荡导致了严重的瓶颈。当两种猎物物种交替出现时，这些现象就可以避免。噬菌体因其更大的爆发量和更快的生命周期而在竞争中胜出。总之，结果表明，蛭弧菌很难在单一猎物上生存，这解释了为什么它一定是一种多面性捕食者，并表明它比噬菌体更适合有多种猎物的环境。重要性抗生素的发现导致传染病导致的死亡人数急剧下降。然而，不断增加的抗菌素耐药性可能会扭转这一进展。因此，需要替代方案，例如基于噬菌体和捕食性细菌的疗法，这些疗法可以杀死细菌，无论它们是病原体还是对抗生素有抗药性。为了最好地利用它们，我们需要更好地了解决定其有效性的因素。通过使用数学模型研究现实缓慢生长条件下的细菌捕食，我们发现通才捕食者蛭弧菌在狭窄的条件范围内对每种猎物最有效。例如，需要最小的猎物细胞大小，并且捕食者不应该“太好”，因为这会导致过度捕捞，从而面临灭绝的风险。这些发现共同深入了解了微生物捕食的生态学，并有助于解释为什么蛭弧菌需要成为多面手捕食者。
With increasing antimicrobial resistance, alternatives for treating infections or removing resistant bacteria are urgently needed, such as the bacterial predator Bdellovibrio bacteriovorus or bacteriophage. Therefore, we need to better understand microbial predator–prey dynamics. We developed mass-action mathematical models of predation for chemostats, which capture the low substrate concentration and slow growth typical for intended application areas of the predators such as wastewater treatment, aquaculture, or the gut. Our model predicted that predator survival required a minimal prey cell size, explaining whyBdellovibriois much smaller than its prey. A predator considered to be “too good” (attack rate too high, mortality too low) overexploited its prey, leading to extinction (tragedy of the commons). Surprisingly, a predator taking longer to produce more offspring outcompeted a predator producing fewer offspring more rapidly (rate versus yield trade-off). Predation was only efficient in a narrow region around optimal parameters. Moreover, extreme oscillations under a wide range of conditions led to severe bottlenecks. These could be avoided when two prey species became available in alternating seasons. A bacteriophage outcompetedBdellovibriodue to its higher burst size and faster life cycle. Together, results suggest thatBdellovibriowould struggle to survive on a single prey, explaining why it must be a generalist predator and suggesting it is better suited than phage to environments with multiple prey.IMPORTANCEThe discovery of antibiotics led to a dramatic drop in deaths due to infectious disease. Increasing levels of antimicrobial resistance, however, threaten to reverse this progress. There is thus a need for alternatives, such as therapies based on phage and predatory bacteria that kill bacteria regardless of whether they are pathogens or resistant to antibiotics. To best exploit them, we need to better understand what determines their effectiveness. By using a mathematical model to study bacterial predation in realistic slow growth conditions, we found that the generalist predatorBdellovibriois most effective within a narrow range of conditions for each prey. For example, a minimum prey cell size is required, and the predator should not be “too good,” as this would result in overexploitation risking extinction. Together these findings give insights into the ecology of microbial predation and help explain whyBdellovibrioneeds to be a generalist predator.