Bacteria dispersal by hitchhiking on zooplankton
Bacteria dispersal by hitchhiking on zooplankton
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DOI：
10.1073/pnas.1000668107
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发表时间：
2010-06-29
影响因子：
11.1
通讯作者：
Tang, Kam W.
中科院分区：
文献类型：
--
作者：
Grossart, Hans-Peter;Dziallas, Claudia;Tang, Kam W.
微生物和浮游动物都是水生食物网的重要组成部分。虽然两者生活在同一环境中，但它们通常被视为通过营养循环和营养级联间接连接的独立功能单元。然而，对病原菌和非病原菌的研究表明，与浮游动物的直接联系对细菌的生理和生态有显着影响。我们使用分层迁移列研究垂直传播的搭便车细菌通过迁移浮游动物的密度梯度，否则无法穿透细菌在向上和向下的方向（走廊带假说）。我们实验的优势在于可以定量估计相关细菌的运输和释放：大型蚤的垂直迁移产生了1.3 × 10（5）个细胞的平均扩散率。湖泊细菌Brevundimonas sp.的迁移周期-1。另外两种细菌也显示出magna，尽管比率较低。在我们的野外研究中证实了浮游动物昼夜洄游在浅水层和浅水层获得不同的附着细菌群落的预测。在中营养型湖泊Nehmitz，D.透明藻表现出明显的昼夜垂直迁移，沿着，附着的细菌群落组成具有显著的昼夜变化。这些结果证实，搭便车迁徙动物可以迅速迁移微生物，包括病原体，使他们能够获得否则无法获得的资源的一个重要机制。
Microorganisms and zooplankton are both important components of aquatic food webs. Although both inhabit the same environment, they are often regarded as separate functional units that are indirectly connected through nutrient cycling and trophic cascade. However, research on pathogenic and nonpathogenic bacteria has shown that direct association with zooplankton has significant influences on the bacteria's physiology and ecology. We used stratified migration columns to study vertical dispersal of hitchhiking bacteria through migrating zooplankton across a density gradient that was otherwise impenetrable for bacteria in both upward and downward directions (conveyor-belt hypothesis). The strength of our experiments is to permit quantitative estimation of transport and release of associated bacteria: vertical migration of Daphnia magna yielded an average dispersal rate of 1.3 x 10(5).cells.Daphnia(-1.) migration cycle-1 for the lake bacterium Brevundimonas sp. Bidirectional vertical dispersal by migrating D. magna was also shown for two other bacterial species, albeit at lower rates. The prediction that diurnally migrating zooplankton acquire different attached bacterial communities from hypolimnion and epilimnion between day and night was subsequently confirmed in our field study. In mesotrophic Lake Nehmitz, D. hyalina showed pronounced diel vertical migration along with significant diurnal changes in attached bacterial community composition. These results confirm that hitchhiking on migrating animals can be an important mechanism for rapidly relocating microorganisms, including pathogens, allowing them to access otherwise inaccessible resources.