Ultrastructure of acidic polysaccharides from the cell walls of brown algae
Ultrastructure of acidic polysaccharides from the cell walls of brown algae
复制标题
DOI：
10.1016/j.jsb.2003.11.011
复制
发表时间：
2004-03-01
影响因子：
3
通讯作者：
Filho, GMA
中科院分区：
文献类型：
--
作者：
Andrade, LR;Salgado, LT;Filho, GMA
我们用多种电子显微镜技术研究了褐藻细胞壁酸性多糖的超微结构。木霉多糖具有自组装结构，形成小梁结构。由褐藻酸和硫酸岩藻聚糖组成的纯化组分也形成了组织良好的超微结构，但组织模式因多糖种类的不同而不同。海藻酸呈海绵状结构。硫酸岩藻聚糖硫酸酯具有多晶体结构的多角形颗粒。这些颗粒实际上是由硫酸化的岩藻糖分子组成的，因为它们被α-L岩藻糖基残基的特异性凝集素识别。X-射线微区分析表明，S是一个组成元素，这与硫酸盐化基团的预期一致。最后，完全纯化的硫酸岩藻糖胶显示出与多边形形成的相同的超微结构。此外，对酸性多糖的元素分析表明，当从污染地区收集藻类时，它们保留了锌。这一观察结果得到了生物质中重金属的直接定量以及与来自非污染地点的藻类相比的溶解多糖中重金属的直接定量支持。我们得出结论，这些分子具有特定的超微结构和元素组成；当藻类暴露在金属污染的环境中时，它们作为金属结合剂成核和沉淀重金属。(C)2003 Elsevier Inc.保留所有权利。
We have studied the ultrastructure of acidic polysaccharides from the cell walls of brown algae using a variety of electron microscopy techniques. Polysaccharides from Padina gymnospora present self assembled structures, forming trabecular patterns. Purified fractions constituted by alginic acid and sulfated fucan also form well-organized ultrastructures, but the pattern of organization varies depending on the polysaccharide species. Alginic acid presents sponge-like structures. Sulfated fucan exhibits particles with polygonal forms with a polycrystalline structure. These particles are in fact constituted by sulfated fucan molecules since they are recognized by a lectin specific for alpha-L-fucosyl residues. X-ray microanalysis reveal that S is a constituent element, as expected for sulfated groups. Finally, an exhaustive purified sulfated fucan shows the same ultrastructure formed by polygonal forms. Furthermore, elemental analyses of acidic polysaccharides indicate that they retain Zn, when algae were collected from a contaminated area. This observation is supported by direct quantification of heavy metal in the biomass and also in the solubilized polysaccharides compared with the algae from a non-contaminated site. We conclude that these molecules have specific ultrastructure and elemental composition; and act as metal binder for the nucleation and precipitation of heavy metals when the algae are exposed to a metal contaminated environment. (C) 2003 Elsevier Inc. All rights reserved.