The predatory bacterium Bdellovibrio bacteriovorus follows a life cycle in which it attaches to the exterior of a Gram-negative prey cell, enters the periplasm, and harvests resources to replicate before lysing the host to find new prey. Predatory bacteria such as this are common in many natural environments, as are groups of matrix-bound clusters of prey cells, termed biofilms. Despite the ubiquity of both predatory bacteria and biofilm-dwelling prey, the interaction between B. bacteriovorus and prey cells inside biofilms has received little attention and has not yet been studied at the micrometer scale. Filling this knowledge is critical to understanding the nature of predator-prey interaction in nature. Here we show that B. bacteriovorus is able to prey upon biofilms of the pathogen Vibrio cholerae, but only up until a critical maturation threshold past which the prey biofilms are protected from their predators. We determine the contribution of matrix secretion and cell-cell packing of the prey biofilm toward this protection mechanism. Our results demonstrate that B. bacteriovorus predation in the context of this protection threshold fundamentally transforms the sub-millimeter scale landscape of biofilm growth, as well as the process of community assembly as new potential biofilm residents enter the system.

中文翻译：

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Bdellovibrio bacteriovorus的捕食改变了细菌生物膜的景观和群落组装

掠食性细菌Bdellovibrio bacteriovorus遵循生命周期，在该生命周期中，它附着于革兰氏阴性猎物细胞的外部，进入周质，并在裂解宿主以寻找新猎物之前收获可复制的资源。诸如此类的掠食性细菌在许多自然环境中都很常见，被基质结合的猎物细胞簇也称为生物膜，它们在群居环境中很常见。尽管掠食性细菌和居住在生物膜中的猎物无处不在，但细菌噬菌芽孢杆菌和生物膜内部的猎物细胞之间的相互作用很少受到关注，并且尚未在微米尺度上进行研究。充实这些知识对于理解自然界中捕食者与猎物之间相互作用的本质至关重要。在这里，我们显示出B. bacteriovorus能够捕食霍乱弧菌病原体的生物膜，但只能直到临界成熟阈值，超过该阈值，猎物生物膜才能免受其掠食者侵害。我们确定猎物生物膜的基质分泌和细胞-细胞堆积对这种保护机制的贡献。我们的研究结果表明，在这种保护阈值范围内，食肉双歧杆菌的捕食从根本上改变了生物膜生长的亚毫米尺度景观，以及新的潜在生物膜居民进入系统时的社区组装过程。