Spectroscopic and biochemical analysis of regions of the cell wall of the unicellular 'mannan weed', Acetabularia acetabulum
Spectroscopic and biochemical analysis of regions of the cell wall of the unicellular 'mannan weed', Acetabularia acetabulum
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DOI：
10.1093/pcp/pcl053
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发表时间：
2007-01-01
影响因子：
4.9
通讯作者：
Mandoli, Dina F.
中科院分区：
文献类型：
--
作者：
Dunn, Erin K.;Shoue, Douglas A.;Mandoli, Dina F.
虽然人们早就知道伞藻属的伞藻（Acetabularia acetabulum）含有富含甘露聚糖的细胞壁，但对于细胞壁组成在多大程度上随该细胞精细的细胞分化而变化，以及还有哪些其他多糖与甘露聚糖共存，都尚不明确。从假根、茎、毛、毛痕、顶端隔膜、配子体和配子囊制备了细胞壁，对其进行了核磁共振和傅里叶变换红外光谱分析，并分析了单糖组成和连接方式，不过材料的局限性使得一些细胞区域无法通过某些方法进行分析。在二倍体阶段，细胞壁含有一种类结晶甘露聚糖，其他多糖占细胞壁质量的10 - 20%；在单倍体阶段，配子囊具有纤维素细胞壁，甘露聚糖和其他聚合物约占质量的四分之一。在二倍体阶段的细胞壁中，甘露聚糖的结晶度似乎比纤维素的典型结晶度低。二倍体和单倍体阶段的细胞壁都几乎不含木葡聚糖或果胶多糖，但似乎含有少量的同型鼠李聚糖、半乳甘露聚糖和葡糖半乳甘露聚糖以及分支木聚糖。这些辅助多糖在富含纤维素的配子囊中的含量与在富含甘露聚糖的二倍体阶段大致相同。在二倍体阶段，细胞的不同区域在细胞壁组成上有适度但可重复的差异。这些结果表明了绒枝藻目富含甘露聚糖的细胞壁具有独特的细胞壁结构。
Although the Dasycladalean alga Acetabularia acetabulum has long been known to contain mannan-rich walls, it is not known to what extent wall composition varies as a function of the elaborate cellular differentiation of this cell, nor has it been determined what other polysaccharides accompany the mannans. Cell walls were prepared from rhizoids, stalks, hairs, hair scars, apical septa, gametophores and gametangia, subjected to nuclear magnetic resonance and Fourier transform infrared spectroscopy, and analyzed for monosaccharide composition and linkage, although material limitations prevented some cell regions from being analyzed by some of the methods. In diplophase, walls contain a para-crystalline mannan, with other polysaccharides accounting for 10-20% of the wall mass; in haplophase, gametangia have a cellulosic wall, with mannans and other polymers representing about a quarter of the mass. In the walls of the diplophase, the mannan appears less crystalline than typical of cellulose. The walls of both diploid and haploid phases contain little if any xyloglucan or pectic polysaccharides, but appear to contain small amounts of a homorhamnan, galactomannans and glucogalactomannans, and branched xylans. These ancillary polysaccharides are approximately as abundant in the cellulose-rich gametangia as in the mannan-rich diplophase. In the diplophase, different regions of the cell differ modestly but reproducibly in the composition of the cell wall. These results suggest unique cell wall architecture for the mannan-rich cell walls of the Dasycladales.