Atypical iron storage in marine brown algae: a multidisciplinary study of iron transport and storage in Ectocarpus siliculosus
Atypical iron storage in marine brown algae: a multidisciplinary study of iron transport and storage in Ectocarpus siliculosus
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DOI：
10.1093/jxb/ers225
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发表时间：
2012-10-01
影响因子：
6.9
通讯作者：
Carrano, Carl J.
中科院分区：
文献类型：
--
作者：
Boettger, Lars H.;Miller, Eric P.;Carrano, Carl J.
铁是所有生物体的必需元素，由于其在氧化还原和其他酶中的普遍作用，特别是在呼吸和光合作用的背景下。陆生/高等植物的铁吸收和储存系统现在已经得到了合理的理解，铁吸收的两种基本策略被区分开来：策略I植物使用的机制涉及诱导Fe（III）-螯合还原酶（铁还原酶）和Fe（II）转运蛋白，而策略II植物利用高亲和力，铁特异性，结合化合物称为植物铁载体。与此相反，很少有人知道在海洋，植物样谱系，特别是那些多细胞藻类（海藻）的相应系统。本文首次报道了棕叶山桐子铁吸收和贮存机制的研究。基因组数据表明，Ectocarpus可能使用的策略I的方法。短期放射性铁摄取的研究证实，铁是采取了Ectocarpus在时间和浓度依赖性的方式与积极的运输过程相一致。在长期暴露于Fe-57后，使用穆斯堡尔谱和X射线吸收光谱的组合鉴定了两种代谢物。这些包括一个铁硫簇占类似的26%的总细胞内铁池和第二个组件与典型的聚合物（Fe 3 + O 6）系统的参数类似的无定形的富磷矿物核心的细菌和植物铁蛋白的光谱。这种铁代谢产物占细胞铁库的74%，表明Ectocarpus含有非铁蛋白但基于矿物质的铁储存库。
Iron is an essential element for all living organisms due to its ubiquitous role in redox and other enzymes, especially in the context of respiration and photosynthesis. The iron uptake and storage systems of terrestrial/higher plants are now reasonably well understood, with two basic strategies for iron uptake being distinguished: strategy I plants use a mechanism involving induction of Fe(III)-chelate reductase (ferrireductase) and Fe(II) transporter proteins, while strategy II plants utilize high-affinity, iron-specific, binding compounds called phytosiderophores. In contrast, little is known about the corresponding systems in marine, plant-like lineages, particularly those of multicellular algae (seaweeds). Herein the first study of the iron uptake and storage mechanisms in the brown alga Ectocarpus siliculosus is reported. Genomic data suggest that Ectocarpus may use a strategy I approach. Short-term radio-iron uptake studies verified that iron is taken up by Ectocarpus in a time- and concentration-dependent manner consistent with an active transport process. Upon long-term exposure to Fe-57, two metabolites have been identified using a combination of Mssbauer and X-ray absorption spectroscopies. These include an ironsulphur cluster accounting for similar to 26% of the total intracellular iron pool and a second component with spectra typical of a polymeric (Fe3+O6) system with parameters similar to the amorphous phosphorus-rich mineral core of bacterial and plant ferritins. This iron metabolite accounts for similar to 74% of the cellular iron pool and suggests that Ectocarpus contains a non-ferritin but mineral-based iron storage pool.