Density-dependent fitness benefits in quorum-sensing bacterial populations
Density-dependent fitness benefits in quorum-sensing bacterial populations
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DOI：
10.1073/pnas.1118131109
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发表时间：
2012-05-22
影响因子：
11.1
通讯作者：
Diggle, Stephen P.
中科院分区：
文献类型：
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作者：
Darch, Sophie E.;West, Stuart A.;Diggle, Stephen P.
有人认为，细菌使用小的可扩散信号分子进行通信，以协调在称为群体感应（QS）的过程中分泌到细胞外的因子的产生。解释QS的基本假设是，这些细胞外因子的分泌在较高的细胞密度下更有益。然而，这一基本假设从未经过实验验证。在这里，我们直接测试，通过独立操纵人口密度和诱导和响应的QS信号，使用机会致病菌铜绿假单胞菌作为模式生物。我们发现，在较高的人口密度下，QS的好处相对较大，这是因为更有效地利用了依赖QS的细胞外“公共产品”。相反，生产“私人物品”的好处，这些物品保留在细胞内，不随细胞密度而变化。总的来说，这些结果支持这样的想法，即QS用于协调高密度下的社会行为的开启，当这些行为更有效时，将提供最大的益处。
It has been argued that bacteria communicate using small diffusible signal molecules to coordinate, among other things, the production of factors that are secreted outside of the cells in a process known as quorum sensing (QS). The underlying assumption made to explain QS is that the secretion of these extracellular factors is more beneficial at higher cell densities. However, this fundamental assumption has never been tested experimentally. Here, we directly test this by independently manipulating population density and the induction and response to the QS signal, using the opportunistic pathogen Pseudomonas aeruginosa as a model organism. We found that the benefit of QS was relatively greater at higher population densities, and that this was because of more efficient use of QS-dependent extracellular "public goods." In contrast, the benefit of producing "private goods," which are retained within the cell, does not vary with cell density. Overall, these results support the idea that QS is used to coordinate the switching on of social behaviors at high densities when such behaviors are more efficient and will provide the greatest benefit.