Use of stable isotope-labelled cells to identify active grazers of picocyanobacteria in ocean surface waters.
Use of stable isotope-labelled cells to identify active grazers of picocyanobacteria in ocean surface waters.
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DOI：
10.1111/j.1462-2920.2008.01793.x
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发表时间：
2009-02
影响因子：
5.1
通讯作者：
Chisholm SW
中科院分区：
文献类型：
--
作者：
Frias-Lopez J;Thompson A;Waldbauer J;Chisholm SW
原氯球菌和聚球藻是种类最丰富的两种海洋蓝藻。它们占世界海洋初级生产总量的很大一部分，占食性原生动物可获得的猎物生物量的很大一部分。尽管增长速度相对较快，但公海表层水域的微囊藻细胞密度保持相当稳定，这意味着由于病毒感染和捕食者的消耗，死亡率稳定。已经有一些关于特定原生生物对培养中的原氯球菌和聚球藻进行放牧的研究，以及由于田间整体放牧而导致的细胞损失率的研究。然而，这些野生初级生产者的具体死亡来源仍不清楚。在这里，我们使用一种改进的RNA稳定同位素探测技术(RNA-SIP)，包括在天然海水中添加标记细胞，以识别特定消费太平洋表层水域中的原氯球菌和聚球藻的活跃捕食者。有4个主要类群的18S rRNA被高度标记：扁藻亚纲(Haptophyta)、扁藻亚纲(Stramenopiles)、大单胞菌属(Bolidomonas)和甲藻亚纲(Dinoflagellata)。对于其中的前三个序列，所确定的最接近的序列是光合作用的有机体，这表明在苦味细菌捕食者中存在混合营养生物。我们的结论是，使用RNA-SIP是一种有用的方法来在原位识别苦味蓝杆菌的特定捕食者，并且该方法可能被用于识别在微生物食物网中重要的其他细菌捕食者。
Prochlorococcus and Synechococcus are the two most abundant marine cyanobacteria. They represent a significant fraction of the total primary production of the world oceans and comprise a major fraction of the prey biomass available to phagotrophic protists. Despite relatively rapid growth rates, picocyanobacterial cell densities in open-ocean surface waters remain fairly constant, implying steady mortality due to viral infection and consumption by predators. There have been several studies on grazing by specific protists on Prochlorococcus and Synechococcus in culture, and of cell loss rates due to overall grazing in the field. However, the specific sources of mortality of these primary producers in the wild remain unknown. Here, we use a modification of the RNA stable isotope probing technique (RNA-SIP), which involves adding labelled cells to natural seawater, to identify active predators that are specifically consuming Prochlorococcus and Synechococcus in the surface waters of the Pacific Ocean. Four major groups were identified as having their 18S rRNA highly labelled: Prymnesiophyceae (Haptophyta), Dictyochophyceae (Stramenopiles), Bolidomonas (Stramenopiles) and Dinoflagellata (Alveolata). For the first three of these, the closest relative of the sequences identified was a photosynthetic organism, indicating the presence of mixotrophs among picocyanobacterial predators. We conclude that the use of RNA-SIP is a useful method to identity specific predators for picocyanobacteria in situ, and that the method could possibly be used to identify other bacterial predators important in the microbial food-web.
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影响因子：
5.1
作者：
Countway, Peter D.;Gast, Rebecca J.;Caron, David A.
通讯作者：
Caron, David A.
影响因子：
2.2
作者：
Adl, SM;Simpson, AGB;Taylor, MFJR
通讯作者：
Taylor, MFJR
影响因子：
5.1
作者：
Christaki, U;Vázquez-Domínguez, E;Lebaron, P
通讯作者：
Lebaron, P
影响因子：
1.4
作者：
Guillou, L;Jacquet, S;Vaulot, D
通讯作者：
Vaulot, D
影响因子：
2.2
作者：
Countway, PD;Gast, RJ;Caron, DA
通讯作者：
Caron, DA