Department of Biology, University of Louisville, Louisville, KY, USA.
Department of Biological Sciences, University of Massachusetts, Lowell, MA, USA.
Proc Biol Sci. 2020 Nov 11;287(1938):20201706. doi: 10.1098/rspb.2020.1706. Epub 2020 Nov 4.
Nearly all bacteria produce narrow-spectrum antibiotics called bacteriocins. Studies have shown that bacteriocins can mediate microbial interactions, but the mechanisms underlying patterns of inhibition are less well understood. We assembled a spatially structured collection of isolates of from bathroom and kitchen sink drains in nine households. Growth inhibition of these by bacteriocins, known as pyocins in this species, was measured using pairwise inhibition assays. Carbon source usage of these isolates was measured, and genetic distance was estimated using multilocus sequencing. We found that as the distance between sites of isolation increased, there was a significantly higher probability of inhibition, and that pyocin inhibition and susceptibility vary greatly among isolates collected from different houses. We also detected support for other mechanisms influencing diversity: inhibition outcomes were influenced by the type of drain from which isolates were collected, and while we found no indication that carbon source utilization influences inhibition, inhibition was favoured at an intermediate genetic distance. Overall, these results suggest that the combined effects of dispersal limitation among sites and competitive exclusion within them maintain diversity in pyocin inhibition and susceptibility phenotypes, and that additional processes such as local adaptation and effects of phylogenetic distance could further contribute to spatial variability.
几乎所有细菌都能产生称为噬菌体的窄谱抗生素。研究表明，噬菌体可以介导微生物相互作用，但抑制模式的机制还不太清楚。我们从九个家庭的浴室和厨房水槽排水管中收集了一个具有空间结构的分离株集合。使用成对抑制测定法测量这些 对噬菌体（在该物种中称为 ）的生长抑制作用。测量了这些分离株的碳源利用情况，并使用多位点测序估计了遗传距离。我们发现，随着分离地点之间距离的增加，抑制的可能性显著增加，并且从不同房屋收集的分离株中，噬菌体抑制和敏感性差异很大。我们还检测到其他影响多样性的机制的支持：抑制结果受到分离株收集的排水管类型的影响，虽然我们没有发现碳源利用会影响抑制的迹象，但在中间遗传距离时抑制会受到青睐。总的来说，这些结果表明，在各个地点之间的扩散限制和它们内部的竞争排斥的综合作用维持了噬菌体抑制和敏感性表型的多样性，并且其他过程，如局部适应和系统发育距离的影响，可能进一步导致空间变异性。
