Concentration-dependent patterns of leucine incorporation by coastal picoplankton
Concentration-dependent patterns of leucine incorporation by coastal picoplankton
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DOI：
10.1128/aem.72.3.2141-2147.2006
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发表时间：
2006-03-01
影响因子：
4.4
通讯作者：
Pernthaler, J
中科院分区：
文献类型：
--
作者：
Alonso, C;Pernthaler, J
沿海远洋环境被认为是功能的溶解有机碳浓度梯度在微观尺度上，它们的特点是显着的季节性差异，基质的异养微型浮游生物的可用性。因此，共存于这种生境中的微生物类群可能在不同浓度下结合底物的能力上有所不同。我们调查了亮氨酸的掺入模式在四个微生物谱系从北海沿海在0.1和100纳米之间的浓度之前和期间的春季浮游植物水华。分析了不同群体中的群体整体掺入率和亮氨酸掺入细胞的分数。除了最高浓度外，在水华之前（13 - 35%）比水华期间（23 - 47%）显著减少了细菌细胞掺入氨基酸。在预开花的情况下，每个活性细胞的掺入率是恒定的0.1 nM以上添加亮氨酸，而它急剧增加，在开花期间与底物浓度。在这两个时间点，在所有浓度下，玫瑰花属进化枝的高比例成员掺入亮氨酸（分别为55至80%和86至94%）。相比之下，亮氨酸掺入细胞的分数大幅增加，从SAR 86分支（8至31%）和DE簇2的黄杆菌-鞘氨醇杆菌（14至33%）的细菌中的底物可用性。海洋Euryarchaeota的掺入模式介于这两个极端之间（分别为30至56%和48至70%）。我们的研究结果表明，微生物类群的营业额的特定基板的贡献可能是浓度依赖性的。这可能有助于我们了解共存种群的特定生态位，这些种群似乎在争夺相同的资源。
Coastal pelagic environments are believed to feature concentration gradients of dissolved organic carbon at a microscale, and they are characterized by pronounced seasonal differences in substrate availability for the heterotrophic picoplankton. Microbial taxa that coexist in such habitats might thus differ in their ability to incorporate substrates at various concentrations. We investigated the incorporation patterns of leucine in four microbial lineages from the coastal North Sea at concentrations between 0.1 and 100 nM before and during a spring phytoplankton bloom. Community bulk incorporation rates and the fraction of leucine-incorporating cells in the different populations were analyzed. Significantly fewer bacterial cells incorporated the amino acid before (13 to 35%) than during (23 to 47%) the bloom at all but the highest concentration. The incorporation rate per active cell in the prebloom situation was constant above 0.1 nM added leucine, whereas it increased steeply with substrate concentration during the bloom. At both time points, a high proportion of members of the Roseobacter clade incorporated leucine at all concentrations (55 to 80% and 86 to 94%, respectively). In contrast, the fractions of leucine-incorporating cells increased substantially with substrate availability in bacteria from the SAR86 clade (8 to 31%) and from DE cluster 2 of the Flavobacteria-Sphingobacteria (14 to 33%). The incorporation patterns of marine Euryarchaeota were between these extremes (30 to 56% and 48 to 70%, respectively). Our results suggest that the contribution of microbial taxa to the turnover of particular substrates may be concentration dependent. This may help us to understand the specific niches of coexisting populations that appear to compete for the same resources.