Chemical Studies on the Mechanisms of Iron Absorption in Chattonella spp.

根据斋户内海Harima Nada海水中铁浓度远低于查托纳氏菌生长所需的铁浓度的事实，本文假设查托纳氏菌对铁有积极的吸收机制。采用80%乙醇提取海马红潮中的培养的c.a antiqua和c.a marina，并对提取液进行柱层和薄层色谱处理。铁螯合物质的存在证实了古花和花花的存在。通过核磁共振和色谱技术，确定了一种螯合物质为去铁胺B。在chatonella的外膜周围也发现了糖萼层，推测糖萼层与所含的酸性多糖参与了铁的吸附。从<Na_2> <CO_3>的c.a antiqua细胞中提取酸性多糖，用DEAE纤维素柱用NaCl （0.25 ~ 2.0 M，pH 2和pH 12）逐级梯度洗脱。磺化多糖将1个铁原子结合到17个葡萄糖分子中。用等离子体光谱仪（日立300）分析了查顿菌和其他浮游植物的重金属含量。基于这些结果，我们假设铁的吸收机制如下。铁，无论是可溶性的还是颗粒状的，被吸附在糖萼层上，与酸性多糖结合，然后转移到铁螯合物质（铁载体）中，从细胞中排泄出来，运输到细胞中进行生化目的。

The facts that iron concentrations in sea water of Harima Nada, Seto Inland Sea, are much less than that required by Chattonella spp. for their growth led the present authors to assume the presence of active absorption mechanisms of iron in Chatonella spp. Cutured C.antiqua and C.marina sampled from red tide of Haima Nada were extracted with 80 % alcohol and the extracts were treated with column and thin layer chromatographies. Presence of iron chelating substances were confirmed in both C.antiqua and C.marina. One of the chelating substances of C.marina was ascertained as deferroxamine B by NMR and chromatographic techniques.Glycocalyx layer was also found around the outer membrane of Chattonella spp., and the layer was assumed to participate in iron abosorption with the acidic polysaccharides contained. Acidic polysaccharides were extracted from C.antiqua cells with <Na_2> <CO_3> and fractionated with DEAE cellulose column by stepwise gradient elution using NaCl (0.25 - 2.0 M,pH 2 and pH 12). Sulfonated polysaccharide fraction conjugates 1 atom of iron in 17 molecules of it glucose. Heavy metal contents in Chattonella spp. and other phytoplankton were also analyzed with plasma spectrometer (Hitachi 300).Based on these results, the iron absorption mechanisms are postulated to be as follows. Iron, either soluble or particulate from, is adsorbed on glycocalyx layerin conjugation with acidic polysaccharides, and, then, transferd to iron chelating substances (siderophores) excreted from cell to transport into the cell for the biochemical purposes.