Production of extracellular Cu complexing ligands by eucaryotic phytoplankton in response to Cu stress
Production of extracellular Cu complexing ligands by eucaryotic phytoplankton in response to Cu stress
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DOI：
10.4319/lo.2000.45.3.0619
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发表时间：
2000-05-01
影响因子：
4.5
通讯作者：
Brand, LE
中科院分区：
文献类型：
--
作者：
Croot, PL;Moffett, JW;Brand, LE
有机螯合剂被认为是最近的生物来源，控制着海水中铜的形成。以往的研究通常将这些铜结合配体分为两类，一类配体(条件稳定性常数10（12)-10(14)M-1）和二类配体(条件稳定性常数10（9)-10(12)M-L）。目前，这些螯合剂的来源和结构尚不清楚。先前的研究表明，在对铜毒性的反应中，海洋蓝藻聚藻球菌的培养产生了一种强配体，其结合强度与1类配体相似。我们通过调查一套铜胁迫海洋真核浮游植物来扩展这项工作，以生产铜结合配体。我们所研究的大多数真核生物物种都没有产生具有1类配体结合强度的配体，但许多物种产生了2类配体。发现一种海洋鞭毛藻能产生很强的配体；然而，开阔海域中鞭毛藻的低丰度可能意味着这种1类配体的来源在沿海水域更为重要。这项调查表明，铜结合配体的生物来源有很多，但在开阔的海洋中，蓝藻等原核生物比真核生物更可能是I类配体的来源。
Organic chelators that are thought to be of recent biological origin control copper speciation in seawater. Previous studies have often resolved these copper binding ligands into two classes, class 1 ligands (conditional stability constants 10(12)-10(14) M-1) and class 2 ligands (conditional stability constants 10(9)-10(12) M-L). At present the sources and structures of these chelators are unknown. Previous work has shown that in response to copper toxicity, cultures of the marine cyanobacteria Synechococcus spp. produce a strong ligand, similar in binding strength to class 1 ligands. We extended this work by surveying a suite of copper-stressed marine eucaryotic phytoplankton for the production of copper binding ligands. Most eucaryotic species we studied did not produce ligands with the binding strength of class 1 ligands, but many produced class 2 ligands. A marine dinoflagellate Amphidinium carterae was found to produce very strong ligands; however, the low abundance of dinoflagellates in the open ocean may mean that this source of class 1 ligands is more important in coastal waters. This survey shows that there are many biological sources of copper binding ligands, but that procaryotes such as cyanobacteria are more plausible sources of class I ligands in the open ocean than eucaryotes.