Nitrogen fixation and transfer in open ocean diatom-cyanobacterial symbioses.
Nitrogen fixation and transfer in open ocean diatom-cyanobacterial symbioses.
复制标题
公海硅藻-蓝藻共生体中的固氮和转移。
DOI：
10.1038/ismej.2011.26
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发表时间：
2011-09
期刊：
影响因子：
--
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中科院分区：
文献类型：
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许多生活在开阔海洋低营养沃茨的硅藻与蓝细菌密切相关。其中一些协会被认为是互惠互利的，其中N2固定蓝藻共生体为硅藻提供N。利用高分辨率纳米尺度二次离子质谱法测定了自然种群中共生蓝藻的固氮率和向硅藻伴侣的氮转移率。在共生体中，固定氮的细胞特异性速率（1.15-71.5 fmol N/细胞h-1）相似，并且还测量了固定氮的快速转移（30分钟内）。硅藻和它们的共生体的类似的增长率进行了测定，共生体的增长率高于估计的自由生活的细胞。当细胞共生时，Richelia和Calothrix共生体的N2固定率估计比自由生活的细胞的固定率估计高171-420倍。当结合后，后两个结果表明，硅藻的合作伙伴影响他们的蓝藻共生体的生长和代谢。我们估计Richelia固定的氮比自身生长所需的多81-744%，高达97.3%的固定氮转移到硅藻伙伴。该研究为共生微生物控制N输入到开放海洋的机制提供了新的信息，共生微生物是广泛存在的，对海洋初级生产非常重要。此外，这是第一次证明N从N2固定剂转移到单细胞伴侣。这些共生体是共生系统中分子调节和营养交换的重要模型。
Many diatoms that inhabit low-nutrient waters of the open ocean live in close association with cyanobacteria. Some of these associations are believed to be mutualistic, where N2-fixing cyanobacterial symbionts provide N for the diatoms. Rates of N2 fixation by symbiotic cyanobacteria and the N transfer to their diatom partners were measured using a high-resolution nanometer scale secondary ion mass spectrometry approach in natural populations. Cell-specific rates of N2 fixation (1.15–71.5 fmol N per cell h−1) were similar amongst the symbioses and rapid transfer (within 30 min) of fixed N was also measured. Similar growth rates for the diatoms and their symbionts were determined and the symbiotic growth rates were higher than those estimated for free-living cells. The N2 fixation rates estimated for Richelia and Calothrix symbionts were 171–420 times higher when the cells were symbiotic compared with the rates estimated for the cells living freely. When combined, the latter two results suggest that the diatom partners influence the growth and metabolism of their cyanobacterial symbionts. We estimated that Richelia fix 81–744% more N than needed for their own growth and up to 97.3% of the fixed N is transferred to the diatom partners. This study provides new information on the mechanisms controlling N input into the open ocean by symbiotic microorganisms, which are widespread and important for oceanic primary production. Further, this is the first demonstration of N transfer from an N2 fixer to a unicellular partner. These symbioses are important models for molecular regulation and nutrient exchange in symbiotic systems.
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DOI：
10.1016/b978-0-12-372522-6.00027-x
发表时间：
2008-01-01
期刊：
NITROGEN IN THE MARINE ENVIRONMENT, 2ND EDITION
影响因子：
--
作者：
Foster, Rachel A.;O'Mullan, Gregory D.
通讯作者：
O'Mullan, Gregory D.
影响因子：
64.8
作者：
Karl, D;Letelier, R;Hebel, D
通讯作者：
Hebel, D
影响因子：
56.9
作者：
Lechene, Claude P.;Luyten, Yvette;Distel, Daniel L.
通讯作者：
Distel, Daniel L.
影响因子：
2.5
作者：
Carpenter, EJ;Montoya, JP;Capone, DG
通讯作者：
Capone, DG
影响因子：
4
作者：
Karl, D;Michaels, A;Stal, L
通讯作者：
Stal, L