Surface properties of SAR11 bacteria facilitate grazing avoidance
Surface properties of SAR11 bacteria facilitate grazing avoidance
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DOI：
10.1038/s41564-017-0030-5
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发表时间：
2017-12-01
影响因子：
28.3
通讯作者：
Yahel, Gitai
中科院分区：
文献类型：
--
作者：
Dadon-Pilosof, Ayelet;Conley, Keats R.;Yahel, Gitai
海洋生态系统由微小的微生物主导，这些微生物在食物网和生物地球化学循环中发挥着重要作用（1）。许多微生物在稀释环境中茁壮成长，因为它们能够定位，附着和使用营养物质和有机物质的补丁（2，3）。我们认为，一些自由生活的浮游细菌已经将它们粘附在营养丰富的有机颗粒上的能力换成了不粘的细胞表面，这有助于它们逃避粘液滤食动物的捕食。我们使用原位取样技术和下一代测序技术相结合的方法来研究生物过滤的微生物在微生物类型的水平。我们的数据表明，一些海洋细菌，最值得注意的是高度丰富的Pelagibacter ubique和大多数其他成员的SAR 11进化枝的Alphaproteobacteria，可以逃避过滤通过滑过的粘液网的远洋和底栖被囊动物。虽然0.3 μ m的聚苯乙烯珠和其他类似大小的细菌被有效地过滤，但SAR 11成员没有被捕获。反相色谱显示，大多数SAR 11细菌的细胞表面的疏水性比其他嗜热菌少得多。我们的数据要求重新考虑表面性质在生物过滤和捕食者-猎物相互作用的水生系统中的作用。
Oceanic ecosystems are dominated by minute microorganisms that play a major role in food webs and biogeochemical cycles(1). Many microorganisms thrive in the dilute environment due to their capacity to locate, attach to, and use patches of nutrients and organic matter(2,3). We propose that some free-living planktonic bacteria have traded their ability to stick to nutrient-rich organic particles for a non-stick cell surface that helps them evade predation by mucous filter feeders. We used a combination of in situ sampling techniques and next-generation sequencing to study the biological filtration of microorganisms at the phylotype level. Our data indicate that some marine bacteria, most notably the highly abundant Pelagibacter ubique and most other members of the SAR 11 clade of the Alphaproteobacteria, can evade filtration by slipping through the mucous nets of both pelagic and benthic tunicates. While 0.3 mu m polystyrene beads and other similarly-sized bacteria were efficiently filtered, SAR11 members were not captured. Reversed-phase chromatography revealed that most SAR11 bacteria have a much less hydrophobic cell surface than that of other planktonic bacteria. Our data call for a reconsideration of the role of surface properties in biological filtration and predator-prey interactions in aquatic systems.