Fibrous matrix component of cell wall in the giant-celled green alga Valonia utricularis observed by atomic force microscopy in liquid
Fibrous matrix component of cell wall in the giant-celled green alga Valonia utricularis observed by atomic force microscopy in liquid
复制标题
原子力显微镜在液体中观察巨细胞绿藻 Valonia utricalis 细胞壁的纤维基质成分
DOI：
10.1007/s00709-018-1251-z
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发表时间：
2018
期刊：
影响因子：
2.9
通讯作者：
Sekida S
中科院分区：
文献类型：
--
作者：
Mine I;Sekida S
巨细胞绿色海藻Valonia的细胞壁呈现纤维素微纤丝（CMFs）的“交叉纤丝”排列。最近使用原子力显微镜（AFM）报道了纤维基质成分盘绕在CMF周围的存在。为了了解这种纤维壁成分的生物学作用，我们试图揭示分离自V的细胞壁的纤维结构的详细形态。利用改进的原子力显微镜方法，对人工海水中的囊泡样品进行了研究。我们还研究了在酸性环境中孵育对纤维结构形态的影响，已知酸性环境使细胞壁易于分离成层。发现薄的纤维状结构缠绕在单个CMF或多个相邻CMF周围，其厚度平均为0.85 nm。与在原始ASW（pH 8）中孵育的那些相比，在酸性ASW（pH 4）中孵育，在质量和数量上大大修改了纤维结构的形态。纤维状结构的厚度平均增加到4.63 nm，观察到显著的变形，并且通过在酸性ASW中孵育，结构的密度降低到不到一半。此外，在人工分离的细胞壁层表面观察到相同的纤维结构延伸到CMF上并形成聚集体。荧光显微镜观察细胞壁处理villosalectin与荧光素异硫氰酸酯结合表明，细胞壁区域的纤维结构存在丰富的AFM观察到的特定标记。根据这些观察，可以假定V.胞囊是细胞壁的基质成分，含有N-乙酰半乳糖胺，通过结合相邻的细胞壁层参与维持细胞壁的完整性，它们的形态和功能为V。囊状体对酸性pH敏感。
The cell walls of the giant-celled green algaValoniaexhibit the “crossed-fibril” arrangement of cellulose microfibrils (CMFs). The existence of fibrous matrix components coiling around the CMFs was recently reported using atomic force microscopy (AFM). To understand the biological role of this fibrous wall component, we attempted to reveal the detailed morphology of the fibrous structure of the cell walls isolated fromV. utricularisspecimens in artificial seawater (ASW), by using an improved method of AFM. We also investigated the effect of incubation in an acidic environment that had been known to make the cell walls liable to separate into layers, on the morphology of the fibrous structures. Thin, fibrous structures were found to entangle around a single CMF or multiple adjacent CMFs, the thickness of which was 0.85 nm on average. Incubation in acidic ASW (pH 4), greatly modified the morphology of the fibrous structures in quality and quantity, compared with those incubated in the original ASW (pH 8). Thickness of the fibrous structures was increased to 4.63 nm on average, remarkable deformations were observed, and the density of the structures was reduced to less than half by incubation in the acidic ASW. In addition, same fibrous structures extended over CMFs and forming aggregates were observed on the surface of the cell wall layers separated artificially. Fluorescence microscopy of cell walls treated withVicia villosalectin conjugated with fluorescein isothiocyanate showed specific labelling of cell wall regions where the fibrous structures were present abundantly as observed by AFM. From these observations, it can be assumed that the fibrous structures ofV. utricularisare the matrix component of the cell wall containingN-acetylgalactosamine, involved in the maintenance of the cell wall integrity through bonding the neighboring cell wall layers, and their morphology and function ofV. utricularisare sensitive to acidic pH.