Quantification of hydroxamate siderophores in soil solutions of podzolic soil profiles in Sweden
Quantification of hydroxamate siderophores in soil solutions of podzolic soil profiles in Sweden
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DOI：
10.1007/s10534-005-8418-8
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发表时间：
2006-06-01
期刊：
影响因子：
3.5
通讯作者：
Lundstrom, Ulla S.
中科院分区：
文献类型：
--
作者：
Essen, Sofia A.;Bylund, Dan;Lundstrom, Ulla S.
浓度高达2和12纳米的异羟肟酸铁载体ferrichrome和ferricrocin，分别确定在土壤溶液中的灰化森林土壤在北方和瑞典南部的四个网站。未检测到铁白杨素。与溶解的有机碳和低分子量有机酸一样，铁载体的最高浓度出现在上层，即莫尔层，残积层和上层淀积层。在南部的网站，浓度的铁色素和ferricrocin都是相似的幅度，并没有不同的两个网站之间。相比之下，在两个北方网站的土壤溶液中含有更多的ferricrocin比ferrichrome; ferricrocin浓度也高于在北方网站比在南方网站。采用高效液相色谱法，用多孔石墨碳柱分离铁色素、铁微素和铁白杨素。通过电喷雾电离质谱（ESI-MS）结合在线样品预浓缩的检测，通过柱切换，使得铁色素、铁白杨素和铁微菌素的检测限为0.1-0.2 nM。通过MS/MS碎片化进一步验证了铁载体的结构身份。铁色素、铁微素和铁白杨素的片段化主要通过肽裂解发生。最强烈的片段的代表是三个铁（III）螯合异羟肟酸残基，即N-5-酰基-N-5-羟基鸟氨酸之一的损失。
Concentrations up to 2 and 12 nM of the hydroxamate siderophores ferrichrome and ferricrocin, respectively, were identified in soil solutions of podzolic forest soils at four sites in both northern and southern Sweden. No ferrichrysin was detected. As with the dissolved organic carbon and low molecular mass organic acids, the highest concentrations of the siderophores were found in the upper layers i.e. the mor layer, the eluvial and upper illuvial horizons. At the southern sites, the concentrations of ferrichrome and ferricrocin were both of similar magnitude and did not differ between the two sites. In contrast, soil solutions at the two northern sites contained more ferricrocin than ferrichrome; the ferricrocin concentrations were also higher at the northern sites than at the southern sites. Analyses were performed by high performance liquid chromatography with a porous graphitic carbon column on which ferrichrome, ferricrocin and ferrichrysin were separated. Detection by electrospray ionization mass spectrometry (ESI-MS) combined with on-line sample pre-concentration, by means of column-switching, enabled detection limits of 0.1-0.2 nM for ferrichrome, ferrichrysin and ferricrocin. The structural identities of the siderophores were further verified by MS/MS fragmentation. Fragmentation of ferrichrome, ferricrocin and ferrichrysin occurred mainly via peptide cleavage. The most intense fragments were typified by the loss of one of the three iron(III) chelating hydroxamate residues, i.e N-5-acyl-N-5-hydroxy ornithine.